Daniel Bernstein

All Publications

• Epstein-Barr virus-associated post-transplant lymphoproliferative disorders in pediatric transplantation: A prospective multicenter study in the United States. Pediatric transplantation Tajima, T., Martinez, O. M., Bernstein, D., Boyd, S. D., Gratzinger, D., Lum, G., Sasaki, K., Tan, B., Twist, C. J., Weinberg, K., Armstrong, B., Desai, D. M., Mazariegos, G. V., Chin, C., Fishbein, T. M., Tekin, A., Venick, R. S., Krams, S. M., Esquivel, C. O. 2024; 28 (4): e14763

  Abstract

  Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorders (PTLD) is the most common malignancy in children after transplant; however, difficulties for early detection may worsen the prognosis.The prospective, multicenter, study enrolled 944 children (≤21 years of age). Of these, 872 received liver, heart, kidney, intestinal, or multivisceral transplants in seven US centers between 2014 and 2019 (NCT02182986). In total, 34 pediatric EBV+ PTLD (3.9%) were identified by biopsy. Variables included sex, age, race, ethnicity, transplanted organ, EBV viral load, pre-transplant EBV serology, immunosuppression, response to chemotherapy and rituximab, and histopathological diagnosis.The uni-/multivariable competing risk analyses revealed the combination of EBV-seropositive donor and EBV-naïve recipient (D+R-) was a significant risk factor for PTLD development (sub-hazard ratio: 2.79 [1.34-5.78], p = .006) and EBV DNAemia (2.65 [1.72-4.09], p < .001). Patients with D+R- were significantly more associated with monomorphic/polymorphic PTLD than those with the other combinations (p = .02). Patients with monomorphic/polymorphic PTLD (n = 21) had significantly more EBV DNAemia than non-PTLD patients (p < .001) and an earlier clinical presentation of PTLD than patients with hyperplasias (p < .001), within 6-month post-transplant. Among non-liver transplant recipients, monomorphic/polymorphic PTLD were significantly more frequent than hyperplasias in patients ≥5 years of age at transplant (p = .01).D+R- is a risk factor for PTLD and EBV DNAemia and associated with the incidence of monomorphic/polymorphic PTLD. Intensive follow-up of EBV viral load within 6-month post-transplant, especially for patients with D+R- and/or non-liver transplant recipients ≥5 years of age at transplant, may help detect monomorphic/polymorphic PTLD early in pediatric transplant.

  View details for DOI 10.1111/petr.14763

  View details for PubMedID 38682750

• Incomplete-penetrant hypertrophic cardiomyopathy MYH7 G256E mutation causes hypercontractility and elevated mitochondrial respiration. Proceedings of the National Academy of Sciences of the United States of America Lee, S., Vander Roest, A. S., Blair, C. A., Kao, K., Bremner, S. B., Childers, M. C., Pathak, D., Heinrich, P., Lee, D., Chirikian, O., Mohran, S. E., Roberts, B., Smith, J. E., Jahng, J. W., Paik, D. T., Wu, J. C., Gunawardane, R. N., Ruppel, K. M., Mack, D. L., Pruitt, B. L., Regnier, M., Wu, S. M., Spudich, J. A., Bernstein, D. 2024; 121 (19): e2318413121

  Abstract

  Determining the pathogenicity of hypertrophic cardiomyopathy-associated mutations in the β-myosin heavy chain (MYH7) can be challenging due to its variable penetrance and clinical severity. This study investigates the early pathogenic effects of the incomplete-penetrant MYH7 G256E mutation on myosin function that may trigger pathogenic adaptations and hypertrophy. We hypothesized that the G256E mutation would alter myosin biomechanical function, leading to changes in cellular functions. We developed a collaborative pipeline to characterize myosin function across protein, myofibril, cell, and tissue levels to determine the multiscale effects on structure-function of the contractile apparatus and its implications for gene regulation and metabolic state. The G256E mutation disrupts the transducer region of the S1 head and reduces the fraction of myosin in the folded-back state by 33%, resulting in more myosin heads available for contraction. Myofibrils from gene-edited MYH7WT/G256E human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) exhibited greater and faster tension development. This hypercontractile phenotype persisted in single-cell hiPSC-CMs and engineered heart tissues. We demonstrated consistent hypercontractile myosin function as a primary consequence of the MYH7 G256E mutation across scales, highlighting the pathogenicity of this gene variant. Single-cell transcriptomic and metabolic profiling demonstrated upregulated mitochondrial genes and increased mitochondrial respiration, indicating early bioenergetic alterations. This work highlights the benefit of our multiscale platform to systematically evaluate the pathogenicity of gene variants at the protein and contractile organelle level and their early consequences on cellular and tissue function. We believe this platform can help elucidate the genotype-phenotype relationships underlying other genetic cardiovascular diseases.

  View details for DOI 10.1073/pnas.2318413121

  View details for PubMedID 38683993

• PEDSQL, EXERCISE CAPACITY, AND ENDOTHELIAL FUNCTION IN PEDIATRIC FONTAN PATIENTS Jose, J., Bernstein, D., Palaniappan, L. P., Leonard, M., Long, J., Desai, M., Lui, M., Davila, T., Cooke, J. P., Olson, I. L., Myers, J. N., Schneider, L., Tierney, E. ELSEVIER SCIENCE INC. 2024: 2407

  View details for Web of Science ID 001324901502441

• MicroRNA-34a-Dependent Attenuation of Angiogenesis in Right Ventricular Failure. Journal of the American Heart Association Reddy, S., Hu, D. Q., Zhao, M., Ichimura, S., Barnes, E. A., Cornfield, D. N., Alejandre Alcázar, M. A., Spiekerkoetter, E., Fajardo, G., Bernstein, D. 2024: e029427

  Abstract

  The right ventricle (RV) is at risk in patients with complex congenital heart disease involving right-sided obstructive lesions. We have shown that capillary rarefaction occurs early in the pressure-loaded RV. Here we test the hypothesis that microRNA (miR)-34a, which is induced in RV hypertrophy and RV failure (RVF), blocks the hypoxia-inducible factor-1α-vascular endothelial growth factor (VEGF) axis, leading to the attenuated angiogenic response and increased susceptibility to RV failure.Mice underwent pulmonary artery banding to induce RV hypertrophy and RVF. Capillary rarefaction occurred immediately. Although hypoxia-inducible factor-1α expression increased (0.12±0.01 versus 0.22±0.03, P=0.05), VEGF expression decreased (0.61±0.03 versus 0.22±0.05, P=0.01). miR-34a expression was most upregulated in fibroblasts (4-fold), but also in cardiomyocytes and endothelial cells (2-fold). Overexpression of miR-34a in endothelial cells increased cell senescence (10±3% versus 22±2%, P<0.05) by suppressing sirtulin 1 expression, and decreased tube formation by 50% via suppression of hypoxia-inducible factor-1α, VEGF A, VEGF B, and VEGF receptor 2. miR-34a was induced by stretch, transforming growth factor-β1, adrenergic stimulation, and hypoxia in cardiac fibroblasts and cardiomyocytes. In mice with RVF, locked nucleic acid-antimiR-34a improved RV shortening fraction and survival half-time and restored capillarity and VEGF expression. In children with congenital heart disease-related RVF, RV capillarity was decreased and miR-34a increased 5-fold.In summary, miR-34a from fibroblasts, cardiomyocytes, and endothelial cells mediates capillary rarefaction by suppressing the hypoxia-inducible factor-1α-VEGF axis in RV hypertrophy/RVF, raising the potential for anti-miR-34a therapeutics in patients with at-risk RVs.

  View details for DOI 10.1161/JAHA.123.029427

  View details for PubMedID 38293915

• Filamin A heart valve disease as a genetic cause of inherited bicuspid and tricuspid aortic valve disease. Heart (British Cardiac Society) Delwarde, C., Toquet, C., Boureau, A. S., Le Ruz, R., Le Scouarnec, S., Mérot, J., Kyndt, F., Bernstein, D., Bernstein, J. A., Aalberts, J. J., Le Marec, H., Schott, J. J., Roussel, J. C., Le Tourneau, T., Capoulade, R. 2023

  Abstract

  Variants in the FLNA gene have been associated with mitral valve dystrophy (MVD), and even polyvalvular disease has been reported. This study aimed to analyse the aortic valve and root involvement in FLNA-MVD families and its impact on outcomes.262 subjects (37 (18-53) years, 140 male, 79 carriers: FLNA+) from 4 FLNA-MVD families were included. Echocardiography was performed in 185 patients and histological analysis in 3 explanted aortic valves. The outcomes were defined as aortic valve surgery or all-cause mortality.Aortic valve alterations were found in 58% of FLNA+ compared with 6% of FLNA- (p<0.001). 9 (13.4%) FLNA+ had bicuspid aortic valve compared with 4 (3.4%) FLNA- (p=0.03). Overall, the transvalvular mean gradient was slightly increased in FLNA+ (4.8 (4.1-6.1) vs 4.0 (2.9-4.9) mm Hg, p=0.02). The sinuses of Valsalva and sinotubular junction diameters were enlarged in FLNA+ subjects (all p<0.05). 8 FLNA+ patients underwent aortic valve surgery (0 in relatives; p<0.001). Myxomatous remodelling with an infiltration of immune cells was observed. Overall survival was similar between FLNA+ versus FLNA- subjects (86±5% vs 85±6%, p=0.36). There was no statistical evidence for an interaction between genetic status and sex (p=0.15), but the survival tended to be impaired in FLNA+ men (p=0.06) whereas not in women (p=0.71).The patients with FLNA variants present frequent aortic valve disease and worse outcomes. Bicuspid aortic valve is more frequent in patients carrying the FLNA-MVD variants. These unique features should be factored into the management of patients with dystrophic and/or bicuspid aortic valve.

  View details for DOI 10.1136/heartjnl-2023-323491

  View details for PubMedID 38148157

• Corrigendum to "Drp1/Fis1 interaction mediates mitochondrial dysfunction in septic cardiomyopathy" [Journal: Molecular of and Cellular Cardiology (2019) May 130;160-169]. Journal of molecular and cellular cardiology Haileselassie, B., Mukherjee, R., Joshi, A. U., Napier, B. A., Massis, L. M., Ostberg, N. P., Queliconi, B. B., Monack, D., Bernstein, D., Mochly-Rosen, D. 2023

  View details for DOI 10.1016/j.yjmcc.2023.11.004

  View details for PubMedID 38000978

• Cryo-electron tomography reveals the structural diversity of cardiac proteins in their cellular context. bioRxiv : the preprint server for biology Woldeyes, R. A., Nishiga, M., Vander Roest, A. S., Engel, L., Giri, P., Montenegro, G. C., Wu, A. C., Dunn, A. R., Spudich, J. A., Bernstein, D., Schmid, M. F., Wu, J. C., Chiu, W. 2023

  Abstract

  Cardiovascular diseases are a leading cause of death worldwide, but our understanding of the underlying mechanisms is limited, in part because of the complexity of the cellular machinery that controls the heart muscle contraction cycle. Cryogenic electron tomography (cryo-ET) provides a way to visualize diverse cellular machinery while preserving contextual information like subcellular localization and transient complex formation, but this approach has not been widely applied to the study of heart muscle cells (cardiomyocytes). Here, we deploy a platform for studying cardiovascular disease by combining cryo-ET with human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). After developing a cryo-ET workflow for visualizing macromolecules in hiPSC-CMs, we reconstructed sub-nanometer resolution structures of the human thin filament, a central component of the contractile machinery. We also visualized a previously unobserved organization of a regulatory complex that connects muscle contraction to calcium signaling (the troponin complex), highlighting the value of our approach for interrogating the structures of cardiac proteins in their cellular context.

  View details for DOI 10.1101/2023.10.26.564098

  View details for PubMedID 37961228

  View details for PubMedCentralID PMC10634850

• Improved Cardiac Performance and Decreased Arrhythmia in Hypertrophic Cardiomyopathy With Non-β-Blocking R-Enantiomer Carvedilol. Circulation Seo, K., Yamamoto, Y., Kirillova, A., Kawana, M., Yadav, S., Huang, Y., Wang, Q., Lane, K. V., Pruitt, B. L., Perez, M. V., Bernstein, D., Wu, J. C., Wheeler, M. T., Parikh, V. N., Ashley, E. A. 2023

  Abstract

  Hypercontractility and arrhythmia are key pathophysiologic features of hypertrophic cardiomyopathy (HCM), the most common inherited heart disease. β-Adrenergic receptor antagonists (β-blockers) are the first-line therapy for HCM. However, β-blockers commonly selected for this disease are often poorly tolerated in patients, where heart-rate reduction and noncardiac effects can lead to reduced cardiac output and fatigue. Mavacamten, myosin ATPase inhibitor recently approved by the US Food and Drug Administration, has demonstrated the ability to ameliorate hypercontractility without lowering heart rate, but its benefits are so far limited to patients with left ventricular (LV) outflow tract obstruction, and its effect on arrhythmia is unknown.We screened 21 β-blockers for their impact on myocyte contractility and evaluated the antiarrhythmic properties of the most promising drug in a ventricular myocyte arrhythmia model. We then examined its in vivo effect on LV function by hemodynamic pressure-volume loop analysis. The efficacy of the drug was tested in vitro and in vivo compared with current therapeutic options (metoprolol, verapamil, and mavacamten) for HCM in an established mouse model of HCM (Myh6R403Q/+ [myosin heavy chain 6]) and iPSC cardiomyocytes derived from patients with HCM (MYH7R403Q/+) [myosin heavy chain 7]).We identified that carvedilol, a β-blocker not commonly used in HCM, suppresses contractile function and arrhythmia by inhibiting RyR2 (ryanodine receptor type 2). Unlike metoprolol (a β1-blocker), carvedilol markedly reduced LV contractility through RyR2 inhibition, while maintaining stroke volume through α1-adrenergic receptor inhibition in vivo. Clinically available carvedilol is a racemic mixture, and the R-enantiomer, devoid of β-blocking effect, retains the ability to inhibit both α1-receptor and RyR2, thereby suppressing contractile function and arrhythmias without lowering heart rate and cardiac output. In Myh6R403Q/+ mice, R-carvedilol normalized hyperdynamic contraction, suppressed arrhythmia, and increased cardiac output better than metoprolol, verapamil, and mavacamten. The ability of R-carvedilol to suppress contractile function was well retained in MYH7R403Q/+ induced pluripotent stem cell cardiomyocytes.R-enantiomer carvedilol attenuates hyperdynamic contraction, suppresses arrhythmia, and at the same time, improves cardiac output without lowering heart rate by dual blockade of α1-adrenergic receptor and RyR2 in mouse and human models of HCM. This combination of therapeutic effects is unique among current therapeutic options for HCM and may particularly benefit patients without LV outflow tract obstruction.

  View details for DOI 10.1161/CIRCULATIONAHA.123.065017

  View details for PubMedID 37850394

• 311.2: Risk factors for Epstein-Barr virus DNAemia in pediatric transplantation: A multicenter study in the United States. Transplantation Tajima, T., Bernstein, D., Boyd, S. D., Gratzinger, D., Lum, G., Sasaki, K., Tan, B., Weinberg, K., Armstrong, B., Brown, M., Chin, C., Desai, D., Fishbein, T. M., Mazariegos, G., Robien, M. A., Tekin, A., Twist, C. J., Venick, R. S., Krams, S. M., Martinez, O. M., Esquivel, C. O. 2023; 107 (10S1): 71-72

  View details for DOI 10.1097/01.tp.0000993400.94644.c0

  View details for PubMedID 37845955

• Genetic and clinical variables act synergistically to impact neurodevelopmental outcomes in children with single ventricle heart disease. Communications medicine Miller, T. A., Hernandez, E. J., Gaynor, J. W., Russell, M. W., Newburger, J. W., Chung, W., Goldmuntz, E., Cnota, J. F., Zyblewski, S. C., Mahle, W. T., Zak, V., Ravishankar, C., Kaltman, J. R., McCrindle, B. W., Clarke, S., Votava-Smith, J. K., Graham, E. M., Seed, M., Rudd, N., Bernstein, D., Lee, T. M., Yandell, M., Tristani-Firouzi, M. 2023; 3 (1): 127

  Abstract

  Recent large-scale sequencing efforts have shed light on the genetic contribution to the etiology of congenital heart defects (CHD); however, the relative impact of genetics on clinical outcomes remains less understood. Outcomes analyses using genetics are complicated by the intrinsic severity of the CHD lesion and interactions with conditionally dependent clinical variables.Bayesian Networks were applied to describe the intertwined relationships between clinical variables, demography, and genetics in a cohort of children with single ventricle CHD.As isolated variables, a damaging genetic variant in a gene related to abnormal heart morphology and prolonged ventilator support following stage I palliative surgery increase the probability of having a low Mental Developmental Index (MDI) score at 14 months of age by 1.9- and 5.8-fold, respectively. However, in combination, these variables act synergistically to further increase the probability of a low MDI score by 10-fold. The absence of a damaging variant in a known syndromic CHD gene and a shorter post-operative ventilator support increase the probability of a normal MDI score 1.7- and 2.4-fold, respectively, but in combination increase the probability of a good outcome by 59-fold.Our analyses suggest a modest genetic contribution to neurodevelopmental outcomes as isolated variables, similar to known clinical predictors. By contrast, genetic, demographic, and clinical variables interact synergistically to markedly impact clinical outcomes. These findings underscore the importance of capturing and quantifying the impact of damaging genomic variants in the context of multiple, conditionally dependent variables, such as pre- and post-operative factors, and demography.

  View details for DOI 10.1038/s43856-023-00361-2

  View details for PubMedID 37758840

  View details for PubMedCentralID PMC10533527

• Impact of Induction Therapy on Rejection in Pediatric Transplantation: A Multicenter Study in the United States Tajima, T., Gallo, A., Bernstein, D., Bonham, C., Boyd, S., Gratzinger, D., Krams, S. M., Lum, G., Sasaki, K., Tan, B., Weinberg, K., Armstrong, B., Brown, M., Chin, C., Desai, D., Fishbein, T., Mazariegos, G., Robien, M., Tekin, A., Twist, C., Venick, R., Martinez, O. M., Esquivel, C. O. ELSEVIER SCIENCE INC. 2023: S1015

  View details for Web of Science ID 001087126904251

• Epstein-Barr Virus-Associated Post-Transplant Lymphoproliferative Disorders in Pediatric Transplantation: A Prospective Multicenter Study in the United States Tajima, T., Bernstein, D., Boyd, S., Gratzinger, D., Lum, G., Sasaki, K., Tan, B., Twist, C., Weinberg, K., Robien, M., Brown, M., Armstrong, B., Desai, D., Mazariegos, G., Chin, C., Fishbein, T., Tekin, A., Venick, R., Martinez, O. M., Krams, S. M., Esquivel, C. O. ELSEVIER SCIENCE INC. 2023: S590

  View details for Web of Science ID 001087126901240

• Contribution of Previously Unrecognized RNA Splice-Altering Variants to Congenital Heart Disease. Circulation. Genomic and precision medicine Young Jang, M., Patel, P. N., Pereira, A. C., Willcox, J. A., Haghighi, A., Tai, A. C., Ito, K., Morton, S. U., Gorham, J. M., McKean, D. M., DePalma, S. R., Bernstein, D., Brueckner, M., Chung, W. K., Giardini, A., Goldmuntz, E., Kaltman, J. R., Kim, R., Newburger, J. W., Shen, Y., Srivastava, D., Tristani-Firouzi, M., Gelb, B. D., Porter, G. A., Seidman, C. E., Seidman, J. G. 2023: e003924

  Abstract

  BACKGROUND: Known genetic causes of congenital heart disease (CHD) explain <40% of CHD cases, and interpreting the clinical significance of variants with uncertain functional impact remains challenging. We aim to improve diagnostic classification of variants in patients with CHD by assessing the impact of noncanonical splice region variants on RNA splicing.METHODS: We tested de novo variants from trio studies of 2649 CHD probands and their parents, as well as rare (allele frequency, <2*10-6) variants from 4472 CHD probands in the Pediatric Cardiac Genetics Consortium through a combined computational and in vitro approach.RESULTS: We identified 53 de novo and 74 rare variants in CHD cases that alter splicing and thus are loss of function. Of these, 77 variants are in known dominant, recessive, and candidate CHD genes, including KMT2D and RBFOX2. In 1 case, we confirmed the variant's predicted impact on RNA splicing in RNA transcripts from the proband's cardiac tissue. Two probands were found to have 2 loss-of-function variants for recessive CHD genes HECTD1 and DYNC2H1. In addition, SpliceAI-a predictive algorithm for altered RNA splicing-has a positive predictive value of 93% in our cohort.CONCLUSIONS: Through assessment of RNA splicing, we identified a new loss-of-function variant within a CHD gene in 78 probands, of whom 69 (1.5%; n=4472) did not have a previously established genetic explanation for CHD. Identification of splice-altering variants improves diagnostic classification and genetic diagnoses for CHD.REGISTRATION: URL: https://clinicaltrials.gov; Unique identifier: NCT01196182.

  View details for DOI 10.1161/CIRCGEN.122.003924

  View details for PubMedID 37165897

• Improved Right Ventricular Energy Efficiency by 4-Dimensional Flow Magnetic Resonance Imaging After Harmony Valve Implantation. JACC. Advances Woo, J. P., Dong, M. L., Kong, F., McElhinney, D. B., Schiavone, N., Chan, F., Lui, G. K., Haddad, F., Bernstein, D., Marsden, A. 2023; 2 (3)

  View details for DOI 10.1016/j.jacadv.2023.100284

  View details for PubMedID 37691969

  View details for PubMedCentralID PMC10487049

• Cardiogenic control of affective behavioural state. Nature Hsueh, B., Chen, R., Jo, Y., Tang, D., Raffiee, M., Kim, Y. S., Inoue, M., Randles, S., Ramakrishnan, C., Patel, S., Kim, D. K., Liu, T. X., Kim, S. H., Tan, L., Mortazavi, L., Cordero, A., Shi, J., Zhao, M., Ho, T. T., Crow, A., Yoo, A. W., Raja, C., Evans, K., Bernstein, D., Zeineh, M., Goubran, M., Deisseroth, K. 2023

  Abstract

  Emotional states influence bodily physiology, as exemplified in the top-down process by which anxiety causes faster beating of the heart1-3. However, whether an increased heart rate might itself induce anxiety or fear responses is unclear3-8. Physiological theories of emotion, proposed over a century ago, have considered that in general, there could be an important and even dominant flow of information from the body to the brain9. Here, to formally test this idea, we developed a noninvasive optogenetic pacemaker for precise, cell-type-specific control of cardiac rhythms of up to 900beats per minute in freely moving mice, enabled by a wearable micro-LED harness and the systemic viral delivery of a potent pump-like channelrhodopsin. We found that optically evoked tachycardia potently enhanced anxiety-like behaviour, but crucially only in risky contexts, indicating that both central (brain) and peripheral (body) processes may be involved in the development of emotional states. To identify potential mechanisms, we used whole-brain activity screening and electrophysiology to find brain regions that wereactivated by imposed cardiac rhythms. We identified the posterior insular cortex as a potential mediator of bottom-up cardiac interoceptive processing, and found that optogenetic inhibition of this brain region attenuated the anxiety-like behaviour that was induced by optical cardiac pacing. Together, these findings reveal that cells of both the body and the brain must be considered together to understand the origins of emotional or affective states. More broadly, our results define a generalizable approach for noninvasive, temporally precise functional investigations of joint organism-wide interactions among targeted cells during behaviour.

  View details for DOI 10.1038/s41586-023-05748-8

  View details for PubMedID 36859543

• Epstein-Barr virus-associated post-transplant lymphoproliferative disorders in pediatric transplantation: A prospective multicenter study in the United States Tajima, T., Bernstein, D., Boyd, S. D., Gratzinger, D., Lum, G., Sasaki, K., Tan, B., Twist, C. J., Weinberg, K., Robien, M. A., Brown, M., Armstrong, B., Desai, D., Mazariegos, G., Chin, C., Fishbein, T. M., Tekin, A., Venick, R. S., Martinez, O. M., Krams, S. M., Esquivel, C. O. WILEY. 2023

  View details for Web of Science ID 001002465500078

• Drp1/p53 interaction mediates p53 mitochondrial localization and dysfunction in septic cardiomyopathy. Journal of molecular and cellular cardiology Mukherjee, R., Tetri, L. H., Li, S. J., Fajardo, G., Ostberg, N. P., Tsegay, K. B., Gera, K., Cornell, T. T., Bernstein, D., Mochly-Rosen, D., Haileselassie, B. 2023; 177: 28-37

  Abstract

  Previous studies have implicated p53-dependent mitochondrial dysfunction in sepsis induced end organ injury, including sepsis-induced myocardial dysfunction (SIMD). However, the mechanisms behind p53 localization to the mitochondria have not been well established. Dynamin-related protein 1 (Drp1), a mediator of mitochondrial fission, may play a role in p53 mitochondrial localization. Here we examined the role of Drp1/p53 interaction in SIMD using in vitro and murine models of sepsis.H9c2 cardiomyoblasts and BALB/c mice were exposed to lipopolysaccharide (LPS) to model sepsis phenotype. Pharmacologic inhibitors of Drp1 activation (ψDrp1) and of p53 mitochondrial binding (pifithrin μ, PFTμ) were utilized to assess interaction between Drp1 and p53, and the subsequent downstream impact on mitochondrial morphology and function, cardiomyocyte function, and sepsis phenotype.Both in vitro and murine models demonstrated an increase in physical Drp1/p53 interaction following LPS treatment, which was associated with increased p53 mitochondrial localization, and mitochondrial dysfunction. This Drp1/p53 interaction was inhibited by ΨDrp1, suggesting that this interaction is dependent on Drp1 activation. Treatment of H9c2 cells with either ΨDrp1 or PFTμ inhibited the LPS mediated localization of Drp1/p53 to the mitochondria, decreased oxidative stress, improved cellular respiration and ATP production. Similarly, treatment of BALB/c mice with either ΨDrp1 or PFTμ decreased LPS-mediated mitochondrial localization of p53, mitochondrial ROS in cardiac tissue, and subsequently improved cardiomyocyte contractile function and survival.Drp1/p53 interaction and mitochondrial localization is a key prodrome to mitochondrial damage in SIMD and inhibiting this interaction may serve as a therapeutic target.

  View details for DOI 10.1016/j.yjmcc.2023.01.008

  View details for PubMedID 36841153

• Mutations In Latent Membrane Protein 1 of Epstein-Barr Virus are Associated with Increased Risk for Post-Transplant Lymphoproliferative Disorder in Children. American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons Martinez, O. M., Krams, S. M., Robien, M. A., Lapasaran, M. G., Arvedson, M. P., Reitsma, A., Balachandran, Y., Harris-Arnold, A., Weinberg, K., Boyd, S. D., Armstrong, B., Trickey, A., Twist, C. J., Gratzinger, D., Tan, B., Brown, M., Chin, C., Desai, D. M., Fishbein, T. M., Mazariegos, G. V., Tekin, A., Venick, R. S., Bernstein, D., Esquivel, C. O. 2023

  Abstract

  Epstein-Barr virus (EBV)+ post-transplant lymphoproliferative disorder (PTLD) results in significant morbidity and mortality in pediatric transplant recipients. Identifying individuals at increased risk of EBV+ PTLD could influence clinical management of immunosuppression and other therapies, improving post-transplant outcomes. A seven-center prospective, observational clinical trial of 872 pediatric transplant recipients evaluated the presence of mutations at position 212 and 366 of EBV latent membrane protein 1 (LMP1) as an indicator of risk for EBV+ PTLD (Clinical Trials: NCT02182986). DNA was isolated from peripheral blood of EBV+ PTLD cases and matched controls (1:2 nested case-control), and the cytoplasmic tail of LMP1 sequenced. Thirty-four participants reached the primary endpoint of biopsy-proven EBV+ PTLD. DNA was sequenced from 32 PTLD cases and 62 matched controls. Both LMP1 mutations were present in 31/32 PTLD cases (96.9%) and in 45/62 matched controls (72.6%) (p=0.005, OR=11.7, 95% CI 1.5, 92.6). The presence of both G212S and S366T carries a nearly 12-fold increased risk for development of EBV+ PTLD. Conversely, transplant recipients without both LMP1 mutations carry a very low risk of PTLD. Analysis of mutations at positions 212 and 366 of LMP1 can be informative in stratifying patients for risk of EBV+ PTLD.

  View details for DOI 10.1016/j.ajt.2023.02.014

  View details for PubMedID 36796762

• Design and Rationale of RE-ENERGIZE FONTAN: RandomizEd Exercise iNtERvention desiGned to maximIZE fitness in FONTAN patients. American heart journal Tierney, E. S., Palaniappan, L., Leonard, M., Long, J., Myers, J., Dávila, T., Lui, M. C., Kogan, F., Olson, I., Punn, R., Desai, M., Schneider, L. M., Wang, C. H., Cooke, J. P., Bernstein, D. 2023

  Abstract

  In this manuscript, we describe the design and rationale of a randomized controlled trial in pediatric Fontan patients to test the hypothesis that a live-video-supervised exercise (aerobic+resistance) intervention will improve cardiac and physical capacity; muscle mass, strength, and function; and endothelial function. Survival of children with single ventricles beyond the neonatal period has increased dramatically with the staged Fontan palliation. Yet, long-term morbidity remains high. By age 40, 50% of Fontan patients will have died or undergone heart transplantation. Factors that contribute to onset and progression of heart failure in Fontan patients remain incompletely understood. However, it is established that Fontan patients have poor exercise capacity which is associated with a greater risk of morbidity and mortality. Furthermore, decreased muscle mass, abnormal muscle function, and endothelial dysfunction in this patient population is known to contribute to disease progression. In adult patients with two ventricles and heart failure, reduced exercise capacity, muscle mass, and muscle strength are powerful predictors of poor outcomes, and exercise interventions can not only improve exercise capacity and muscle mass, but also reverse endothelial dysfunction. Despite these known benefits of exercise, pediatric Fontan patients do not exercise routinely due to their chronic condition, perceived restrictions to exercise, and parental overprotection. Limited exercise interventions in children with congenital heart disease have demonstrated that exercise is safe and effective; however, these studies have been conducted in small, heterogeneous groups, and most had few Fontan patients. Critically, adherence is a major limitation in pediatric exercise interventions delivered on-site, with adherence rates as low as 10%, due to distance from site, transportation difficulties, and missed school or workdays. To overcome these challenges, we utilize live-video conferencing to deliver the supervised exercise sessions. Our multidisciplinary team of experts will assess the effectiveness of a live-video-supervised exercise intervention, rigorously designed to maximize adherence, and improve key and novel measures of health in pediatric Fontan patients associated with poor long-term outcomes. Our ultimate goal is the translation of this model to clinical application as an "exercise prescription" to intervene early in pediatric Fontan patients and decrease long-term morbidity and mortality.

  View details for DOI 10.1016/j.ahj.2023.02.006

  View details for PubMedID 36796574

• The Z-disc: Mechanosensor at the interface between myosin biomechanics and hypertrophic signaling Giri, P., Roest, A., Lee, S., Heinrich, P., Dunn, A. R., Wu, S., Bernstein, D. CELL PRESS. 2023: 404A

  View details for Web of Science ID 000989629702211

• Changes in myosin biomechanics influence growth and maturation of iPSC-cardiomyocytes. Biophysical journal Bernstein, D., Vander Roest, A. S., Wu, S., Pruitt, B., Zhao, M., Fajardo, G., Ruppel, K., Spudich, J. A. 2023; 122 (3S1): 148a

  View details for DOI 10.1016/j.bpj.2022.11.1014

  View details for PubMedID 36782680

• The Z-disc: Mechanosensor at the interface between myosin biomechanics and hypertrophic signaling. Biophysical journal Giri, P., Vander Roest, A. S., Lee, S., Heinrich, P., Dunn, A. R., Wu, S., Bernstein, D. 2023; 122 (3S1): 404a

  View details for DOI 10.1016/j.bpj.2022.11.2198

  View details for PubMedID 36784062

• Sarcomere dynamics simulations to uncover mechanisms in hypertrophic cardiomyopathy Vander Roest, A. S., Spudich, J. A., Ruppel, K., Regnier, M., Bernstein, D. CELL PRESS. 2023: 148A-149A

  View details for Web of Science ID 000989629700725

• Changes in myosin biomechanics influence growth and maturation of iPSC-cardiomyocytes Bernstein, D., Vander Roest, A. S., Wu, S., Pruitt, B., Zhao, M., Fajardo, G., Ruppel, K., Spudich, J. A. CELL PRESS. 2023: 148A

  View details for Web of Science ID 000989629700722

• Sarcomere dynamics simulations to uncover mechanisms in hypertrophic cardiomyopathy. Biophysical journal Roest, A. S., Spudich, J. A., Ruppel, K., Regnier, M., Bernstein, D. 2023; 122 (3S1): 148a-149a

  View details for DOI 10.1016/j.bpj.2022.11.1017

  View details for PubMedID 36782679

• DRP1/P53 INTERACTION PLAYS A KEY ROLE IN MITOCHONDRIAL DYSFUNCTION OF SEPTIC CARDIOMYOPATHY Tetri, L., Mukherjee, R., Li, S., Fajardo, G., Ostberg, N., Tsegay, K., Gera, K., Cornell, T., Bernstein, D., Mochly-Rosen, D., Haileselassie, B. LIPPINCOTT WILLIAMS & WILKINS. 2023: 617

  View details for Web of Science ID 000921450901535

• Improved Right Ventricular Energy Efficiency by 4-Dimensional Flow Magnetic Resonance Imaging After Harmony Valve Implantation JACC:Advances Woo, J. P., Dong, M. L., Kong, F., McElhinney, D. B., Schiavone, N., Chan, F., Lui, G. K., Haddad, F., Bernstein, D., Marsden, A. 2023; 2 (3)

  View details for DOI 10.1016/j.jacadv.2023.100284

• Increased risk of infections in pediatric Fontan patients after heart transplantation. Pediatric transplantation Ahmed, H., Lee, J., Bernstein, D., Rosenthal, D., Dykes, J., Lee, D., Barkoff, L., Weinberg, K., Hollander, S. A., Chen, S. 2022: e14421

  Abstract

  BACKGROUND: Infectious complications are a major cause of morbidity and mortality after HT. Fontan patients may be more susceptible to post-HT infections.METHODS: This was a single-center, retrospective cohort analysis of pediatric patients undergoing HT for FF physiology or DCM, who underwent induction with ATG. The primary endpoint was an infection in the first 180days post-HT, defined as positive (1) blood/urine/respiratory culture; (2) viral PCR; (3) skin or wound infection; and/or (4) culture-negative infection if ≥5days of antibiotics were completed. Secondary endpoints included (1) cell counts after ATG; (2) PTLD; and (3) rejection (≥Grade 2R ACR or pAMR2) in the first 180days post-HT.RESULTS: A total of 59 patients (26 FF, 33 DCM) underwent HT at 14.7 (IQR 10.6, 19.5) and 11.7 (IQR 1.4, 13.6) years of age, respectively. The median total ATG received was 7.4 (IQR 4.9, 7.7) vs 7.5 (IQR 7.3, 7.6) mg/kg (p=NS) for FF and DCM patients, respectively. Twenty-three patients (39%) developed an infection 180days post-HT, with a higher rate of infection in FF patients (54% vs 27%, p=.03). Adjusted for pre-transplant absolute lymphocyte count, FF patients had a higher risk of infection at 30days post-HT (OR 7.62, 95% CI 1.13-51.48, p=.04). There was no difference in the incidence of PTLD (12% vs 0%; p=.08) or rejection (12% vs 21%; p=.49).CONCLUSION: Compared to DCM patients, FF patients have a higher risk of infection. Modifications to induction therapy for FF patients should be considered.

  View details for DOI 10.1111/petr.14421

  View details for PubMedID 36303275

• Blood flow modeling reveals improved collateral artery performance during the regenerative period in mammalian hearts. Nature cardiovascular research Anbazhakan, S., Rios Coronado, P. E., Sy-Quia, A. N., Seow, L. W., Hands, A. M., Zhao, M., Dong, M. L., Pfaller, M. R., Amir, Z. A., Raftrey, B. C., Cook, C. K., D'Amato, G., Fan, X., Williams, I. M., Jha, S. K., Bernstein, D., Nieman, K., Pașca, A. M., Marsden, A. L., Horse, K. R. 2022; 1 (8): 775-790

  Abstract

  Collateral arteries bridge opposing artery branches, forming a natural bypass that can deliver blood flow downstream of an occlusion. Inducing coronary collateral arteries could treat cardiac ischemia, but more knowledge on their developmental mechanisms and functional capabilities is required. Here we used whole-organ imaging and three-dimensional computational fluid dynamics modeling to define spatial architecture and predict blood flow through collaterals in neonate and adult mouse hearts. Neonate collaterals were more numerous, larger in diameter and more effective at restoring blood flow. Decreased blood flow restoration in adults arose because during postnatal growth coronary arteries expanded by adding branches rather than increasing diameters, altering pressure distributions. In humans, adult hearts with total coronary occlusions averaged 2 large collaterals, with predicted moderate function, while normal fetal hearts showed over 40 collaterals, likely too small to be functionally relevant. Thus, we quantify the functional impact of collateral arteries during heart regeneration and repair-a critical step toward realizing their therapeutic potential.

  View details for DOI 10.1038/s44161-022-00114-9

  View details for PubMedID 37305211

  View details for PubMedCentralID PMC10256232

• Fatal nocardiosis infection in a pediatric patient with an immunodeficiency after heart re-transplantation. Pediatric transplantation Mai, D. H., Sedler, J., Weinberg, K., Bernstein, D., Schroeder, A., Mathew, R., Chen, S., Lee, D., Dykes, J. C., Hollander, S. A. 2022: e14344

  Abstract

  BACKGROUND: Nocardia infections are rare opportunistic infections in SOT recipients, with few reported pediatric cases. Pediatric patients with single ventricle congenital heart defects requiring HT may be more susceptible to opportunistic infections due to a decreased T-cell repertoire from early thymectomy and potential immunodeficiencies related to their congenital heart disease. Other risk factors in SOT recipients include the use of immunosuppressive medications and the development of persistent lymphopenia, delayed count recovery and/or lymphocyte dysfunction.METHODS: We report the case of a patient with hypoplastic left heart syndrome who underwent neonatal congenital heart surgery (with thymectomy) prior to palliative surgery and 2 HTs.RESULTS: After developing respiratory and neurological symptoms, the patient was found to be positive for Nocardia farcinica by BAL culture and cerebrospinal fluid PCR. Immune cell phenotyping demonstrated an attenuated T and B-cell repertoire. Despite antibiotic and immunoglobulin therapy, his symptoms worsened and he was subsequently discharged with hospice care.CONCLUSION: Pediatric patients with a history of congenital heart defects who undergo neonatal thymectomy prior to heart transplantation and a long-term history of immunosuppression should undergo routine immune system profiling to evaluate for T- and B-cell deficiency as risk factors for opportunistic infection. Such patients could benefit from long-term therapy with TMP/SMX for optimal antimicrobial prophylaxis, with desensitization as needed for allergies. Disseminated nocardiosis should be considered when evaluating acutely ill SOT recipients, especially those with persistent lymphopenia and known or suspected secondary immunodeficiencies.

  View details for DOI 10.1111/petr.14344

  View details for PubMedID 35726843

• Mitochondrial Quality Control in the Heart: The Balance between Physiological and Pathological Stress. Biomedicines Fajardo, G., Coronado, M., Matthews, M., Bernstein, D. 2022; 10 (6)

  Abstract

  Alterations in mitochondrial function and morphology are critical adaptations to cardiovascular stress, working in concert in an attempt to restore organelle-level and cellular-level homeostasis. Processes that alter mitochondrial morphology include fission, fusion, mitophagy, and biogenesis, and these interact to maintain mitochondrial quality control. Not all cardiovascular stress is pathologic (e.g., ischemia, pressure overload, cardiotoxins), despite a wealth of studies to this effect. Physiological stress, such as that induced by aerobic exercise, can induce morphologic adaptations that share many common pathways with pathological stress, but in this case result in improved mitochondrial health. Developing a better understanding of the mechanisms underlying alterations in mitochondrial quality control under diverse cardiovascular stressors will aid in the development of pharmacologic interventions aimed at restoring cellular homeostasis.

  View details for DOI 10.3390/biomedicines10061375

  View details for PubMedID 35740401

• EBV plus PTLD Tumor MicroRNAs Detected in Circulating Extracellular Vesicles Are Decreased in Pediatric Transplant Recipients with EBV plus PTLD. Sen, A., Enriquez, J., Rao, M., Glass, M., Balachandran, Y., Syed, S., Twist, C., Weinberg, K., Boyd, S. D., Bernstein, D., Trickey, A., Gratzinger, D., Tan, B., Lapasaran, M. G., Robien, M. A., Brown, M., Armstrong, B., Sever, M., Desai, D., Mazariegos, G., Chin, C., Fishbein, T., Venick, R. S., Tekin, A., Zimmermann, H., Trappe, R. U., Esquivel, C. O., Martinez, O. M., Krams, S. M. WILEY. 2022: 360

  View details for Web of Science ID 000842606302062

• Hybrid management of dysphagia lusoria in a boy with Duchenne's muscular dystrophy. Cardiology in the young Chiu, P., Perry, S., Bernstein, D., Maeda, K. 2022: 1-3

  Abstract

  We present a case of dysphagia lusoria in a wheelchair-bound 9-year-old boy with Duchenne's muscular dystrophy. Due to the patient's limited mobility and restrictive ventilatory defect, the patient was too high risk for open repair, and hybrid revascularisation with carotid-to-subclavian bypass and endovascular occlusion of the proximal right subclavian was undertaken. The patient has been followed up for 18 months with no residual symptoms.

  View details for DOI 10.1017/S1047951122000452

  View details for PubMedID 35414368

• Neither cardiac mitochondrial DNA variation or copy number contribute to congenital heart disease risk. American journal of human genetics Willcox, J. A., Geiger, J. T., Morton, S. U., McKean, D., Quiat, D., Gorham, J. M., Tai, A. C., DePalma, S., Bernstein, D., Brueckner, M., Chung, W. K., Giardini, A., Goldmuntz, E., Kaltman, J. R., Kim, R., Newburger, J. W., Shen, Y., Srivastava, D., Tristani-Firouzi, M., Gelb, B., Porter, G. A., Seidman, J. G., Seidman, C. E. 2022

  Abstract

  The well-established manifestation of mitochondrial mutations in functional cardiac disease (e.g., mitochondrial cardiomyopathy) prompted the hypothesis that mitochondrial DNA (mtDNA) sequence and/or copy number (mtDNAcn) variation contribute to cardiac defects in congenital heart disease (CHD). MtDNAcns were calculated and rare, non-synonymous mtDNA mutations were identified in 1,837 CHD-affected proband-parent trios, 116 CHD-affected singletons, and 114 paired cardiovascular tissue/blood samples. The variant allele fraction (VAF) of heteroplasmic variants in mitochondrial RNA from 257 CHD cardiovascular tissue samples was also calculated. On average, mtDNA from blood had 0.14 rare variants and 52.9 mtDNA copies per nuclear genome per proband. No variation with parental age at proband birth or CHD-affected proband age was seen. mtDNAcns in valve/vessel tissue (320 ± 70) were lower than in atrial tissue (1,080 ± 320, p= 6.8E-21), which were lower than in ventricle tissue (1,340 ± 280, p= 1.4E-4). The frequency of rare variants in CHD-affected individual DNA was indistinguishable from the frequency in an unaffected cohort, and proband mtDNAcns did not vary from those of CHD cohort parents. In both the CHD and the comparison cohorts, mtDNAcns were significantly correlated between mother-child, father-child, and mother-father. mtDNAcns among people with European (mean= 52.0), African (53.0), and Asian haplogroups (53.5) were calculated and were significantly different for European and Asian haplogroups (p= 2.6E-3). Variant heteroplasmic fraction (HF) in blood correlated well with paired cardiovascular tissue HF (r= 0.975) and RNA VAF (r= 0.953), which suggests blood HF is a reasonable proxy for HF in heart tissue. We conclude that mtDNA mutations and mtDNAcns are unlikely to contribute significantly to CHD risk.

  View details for DOI 10.1016/j.ajhg.2022.03.011

  View details for PubMedID 35397206

• Mutations in latent membrane protein 1 of Epstein Barr virus are associated with increased risk of post-transplant lymphoproliferative disorder Martinez, O. M., Krams, S. M., Robien, M., Lapasaran, M. M., Arvedson, M., Reitsma, A., Weinberg, K., Boyd, S., Armstrong, B., Twist, C., Gratzinger, D., Tan, B., Trickey, A., Sever, M., Brown, M., Bernstein, D., Esquivel, C., CTOC 06 Investigators WILEY. 2022

  View details for Web of Science ID 000783167500008

• Memory B Cell Deficiency and Disseminated Nocardiosis in a Pediatric Patient with Congenital Single Ventricle Physiology and Heart Transplantation Sedler, J., Schroeder, A. R., Mathew, R., Chen, S., Weinberg, K. I., Bernstein, D., Lee, D., Dykes, J., Hollander, S. A. ELSEVIER SCIENCE INC. 2022: S513

  View details for Web of Science ID 000780119701524

• Genome-Wide De Novo Variants in Congenital Heart Disease Are Not Associated With Maternal Diabetes or Obesity. Circulation. Genomic and precision medicine Morton, S. U., Pereira, A. C., Quiat, D., Richter, F., Kitaygorodsky, A., Hagen, J., Bernstein, D., Brueckner, M., Goldmuntz, E., Kim, R. W., Lifton, R. P., Porter, G. A., Tristani-Firouzi, M., Chung, W. K., Roberts, A., Gelb, B. D., Shen, Y., Newburger, J. W., Seidman, J. G., Seidman, C. E. 2022: CIRCGEN121003500

  Abstract

  BACKGROUND: Congenital heart disease (CHD) is the most common anomaly at birth, with a prevalence of 1%. While infants born to mothers with diabetes or obesity have a 2- to 3-fold increased incidence of CHD, the cause of the increase is unknown. Damaging de novo variants (DNV) in coding regions are more common among patients with CHD, but genome-wide rates of coding and noncoding DNVs associated with these prenatal exposures have not been studied in patients with CHD.METHODS: DNV frequencies were determined for 1812 patients with CHD who had whole-genome sequencing and prenatal history data available from the Pediatric Cardiac Genomics Consortium's CHD GENES study. The frequency of DNVs was compared between subgroups using t test or linear model.RESULTS: DNV frequencies were compared for 1812 patients with CHD and prenatal history data who were recruited to the Pediatric Cardiac Genomics Consortium's CHD GENES study. The number of DNVs per CHD patient was higher with exposure to maternal diabetes (76.5 versus 72.1, t test P=3.03*10-11), but the difference was no longer significant after including parental ages in a linear model (paternal and maternal correction P=0.42). No interaction was observed between diabetes risk and parental age (paternal and maternal interaction P=0.80 and 0.68, respectively). No difference was seen in DNV count per patient based on maternal obesity (72.0 versus 72.2 for maternal body mass index <25 versus maternal body mass index >30, t test P=0.86).CONCLUSIONS: After accounting for parental age, the offspring of diabetic or obese mothers have no increase in DNVs compared with other children with CHD. These results emphasize the role for other mechanisms in the cause of CHD associated with these prenatal exposures.REGISTRATION: URL: https://clinicaltrials.gov; NCT01196182.

  View details for DOI 10.1161/CIRCGEN.121.003500

  View details for PubMedID 35130025

• Host microRNAs are decreased in pediatric solid-organ transplant recipients during EBV+ Post-transplant Lymphoproliferative Disorder. Frontiers in immunology Sen, A., Enriquez, J., Rao, M., Glass, M., Balachandran, Y., Syed, S., Twist, C. J., Weinberg, K., Boyd, S. D., Bernstein, D., Trickey, A. W., Gratzinger, D., Tan, B., Lapasaran, M. G., Robien, M. A., Brown, M., Armstrong, B., Desai, D., Mazariegos, G., Chin, C., Fishbein, T. M., Venick, R. S., Tekin, A., Zimmermann, H., Trappe, R. U., Anagnostopoulos, I., Esquivel, C. O., Martinez, O. M., Krams, S. M. 2022; 13: 994552

  Abstract

  Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of solid organ transplantation. Predisposing factors include primary Epstein-Barr virus (EBV) infection, reactivation of EBV in recipient B cells, and decreased T cell immunity due to immunosuppression. In our previous studies EBV infection was demonstrated to markedly alter the expression of host B cell microRNA (miR). Specifically, miR-194 expression was uniquely suppressed in EBV+ B cell lines from PTLD patients and the 3'untranslated region of IL-10 was determined to be targeted by miR-194. Although EBV has been shown to regulate host miR expression in B cell lymphoma cell lines, the expression of miRs in the circulation of patients with EBV-associated PTLD has not been studied. The objective of this study was to determine if changes in miR expression are associated with EBV+ PTLD. In this study, we have shown that miR-194 is significantly decreased in EBV+PTLD tumors and that additional miRs, including miRs-17, 19 and 106a are also reduced in EBV+PTLD as compared to EBV-PTLD. We quantitated the levels of miRs-17, 19, 106a, 155, and 194 in the plasma and extracellular vesicles (EV; 50-70 nm as determined by nanoparticle tracking analysis) from pediatric recipients of solid organ transplants with EBV+ PTLD+ that were matched 1:2 with EBV+ PTLD- pediatric transplant recipients as part of the NIH-sponsored Clinical Trials in Organ Transplantation in Children, (CTOTC-06) study. Levels of miRs-17, 19, 106a, and 194 were reduced in the plasma and extracellular vesicles (EV) of EBV+ PTLD+ group compared to matched controls, with miRs-17 (p = 0.034; plasma), miRs-19 (p = 0.029; EV) and miR-106a (p = 0.007; plasma and EV) being significantly reduced. Similar levels of miR-155 were detected in the plasma and EV of all pediatric SOT recipients. Importantly, ~90% of the cell-free miR were contained within the EV supporting that EBV+ PTLD tumor miR are detected in the circulation and suggesting that EVs, containing miRs, may have the potential to target and regulate cells of the immune system. Further development of diagnostic, mechanistic and potential therapeutic uses of the miRs in PTLD is warranted.

  View details for DOI 10.3389/fimmu.2022.994552

  View details for PubMedID 36304469

• Coronary blood vessels from distinct origins converge to equivalent states during mouse and human development. eLife Phansalkar, R., Krieger, J., Zhao, M., Kolluru, S. S., Jones, R. C., Quake, S. R., Weissman, I., Bernstein, D., Winn, V. D., D'Amato, G., Red-Horse, K. 1800; 10

  Abstract

  Most cell fate trajectories during development follow a diverging, tree-like branching pattern, but the opposite can occur when distinct progenitors contribute to the same cell type. During this convergent differentiation, it is unknown if cells 'remember' their origins transcriptionally or whether this influences cell behavior. Most coronary blood vessels of the heart develop from two different progenitor sources-the endocardium (Endo) and sinus venosus (SV)-but whether transcriptional or functional differences related to origin are retained is unknown. We addressed this by combining lineage tracing with single-cell RNA sequencing (scRNAseq) in embryonic and adult mouse hearts. Shortly after coronary development begins, capillary endothelial cells (ECs) transcriptionally segregated into two states that retained progenitor-specific gene expression. Later in development, when the coronary vasculature is well established but still remodeling, capillary ECs again segregated into two populations, but transcriptional differences were primarily related to tissue localization rather than lineage. Specifically, ECs in the heart septum expressed genes indicative of increased local hypoxia and decreased blood flow. Adult capillary ECs were more homogeneous with respect to both lineage and location. In agreement, SV- and Endo-derived ECs in adult hearts displayed similar responses to injury. Finally, scRNAseq of developing human coronary vessels indicated that the human heart followed similar principles. Thus, over the course of development, transcriptional heterogeneity in coronary ECs is first influenced by lineage, then by location, until heterogeneity declines in the homeostatic adult heart. These results highlight the plasticity of ECs during development, and the validity of the mouse as a model for human coronary development.

  View details for DOI 10.7554/eLife.70246

  View details for PubMedID 34910626

• Coronary blood vessels from distinct origins converge to equivalent states during mouse and human development ELIFE Phansalkar, R., Krieger, J., Zhao, M., Kolluru, S., Jones, R. C., Quake, S. R., Weissman, I., Bernstein, D., Winn, V. D., D'Amato, G., Red-Horse, K. 2021; 10

  View details for DOI 10.7554/eLife.70246.sa2

  View details for Web of Science ID 000730934300001

• Identification of Drug Transporter Genomic Variants and Inhibitors that Protect Against Doxorubicin-Induced Cardiotoxicity. Circulation Magdy, T., Jouni, M., Kuo, H., Weddle, C. J., Lyra-Leite, D., Fonoudi, H., Romero-Tejeda, M., Gharib, M., Javed, H., Fajardo, G., Ross, C. J., Carleton, B. C., Bernstein, D., Burridge, P. W. 2021

  Abstract

  Background: Multiple pharmacogenomic studies have identified the synonymous genomic variant rs7853758 (G>A, L461L) and the intronic variant rs885004 in SLC28A3 as statistically associated with a lower incidence of anthracycline-induced cardiotoxicity (AIC). However, the true causal variant(s), the cardioprotective mechanism of this locus, the role of SLC28A3 and other solute carrier (SLC) transporters in AIC, and the suitability of SLC transporters as targets for cardioprotective drugs has not been investigated. Methods: Six well-phenotyped, doxorubicin-treated pediatric patients from the original association study cohort were re-recruited and human induced pluripotent stem cell-derived cardiomyocytes were generated. Patient-specific doxorubicin-induced cardiotoxicity (DIC) was then characterized using assays of cell viability, activated caspase 3/7, and doxorubicin uptake. The role of SLC28A3 in DIC was then queried using overexpression and knockout of SLC28A3 in isogenic hiPSCs using a CRISPR/Cas9. Fine-mapping of the SLC28A3 locus was then completed after SLC28A3 resequencing and an extended in silico haplotype and functional analysis. Genome editing of potential causal variant was done using cytosine base editor. SLC28A3-AS1 overexpression was done using a lentiviral plasmid-based transduction and was validated using stranded RNA-Seq after ribosomal RNA depletion. Drug screening was done using the Prestwick drug library (n = 1200) followed by in vivo validation in mice. The effect of desipramine on DOX cytotoxicity was also investigated in eight cancer cell lines. Results: Here, using the most commonly used anthracycline, doxorubicin, we demonstrate that patient-derived cardiomyocytes recapitulate the cardioprotective effect of the SLC28A3 locus and that SLC28A3 expression influences the severity of DIC. Using Nanopore-based fine-mapping and base editing we identify a novel cardioprotective SNP rs11140490 in the SLC28A3 locus which exerts its effect by regulating an antisense long noncoding-RNA (SLC28A3-AS1) that overlaps with SLC28A3. Using high-throughput drug screening in patient-derived cardiomyocytes and whole organism validation in mice, we identify the SLC competitive inhibitor desipramine as protective against DIC. Conclusions: This work demonstrates the power of the human induced pluripotent stem cell model to take a SNP from a statistical association through to drug discovery, providing human cell-tested data for clinical trials to attenuate DIC.

  View details for DOI 10.1161/CIRCULATIONAHA.121.055801

  View details for PubMedID 34874743

• Altered Cardiac Energetics and Mitochondrial Dysfunction in Hypertrophic Cardiomyopathy. Circulation Ranjbarvaziri, S., Kooiker, K. B., Ellenberger, M., Fajardo, G., Zhao, M., Vander Roest, A. S., Woldeyes, R. A., Koyano, T. T., Fong, R., Ma, N., Tian, L., Traber, G. M., Chan, F., Perrino, J., Reddy, S., Chiu, W., Wu, J. C., Woo, J. Y., Ruppel, K. M., Spudich, J. A., Snyder, M. P., Contrepois, K., Bernstein, D. 2021

  Abstract

  Background: Hypertrophic cardiomyopathy (HCM) is a complex disease partly explained by the effects of individual gene variants on sarcomeric protein biomechanics. At the cellular level, HCM mutations most commonly enhance force production, leading to higher energy demands. Despite significant advances in elucidating sarcomeric structure-function relationships, there is still much to be learned about the mechanisms that link altered cardiac energetics to HCM phenotypes. In this work, we test the hypothesis that changes in cardiac energetics represent a common pathophysiologic pathway in HCM. Methods: We performed a comprehensive multi-omics profile of the molecular (transcripts, metabolites, and complex lipids), ultrastructural, and functional components of HCM energetics using myocardial samples from 27 HCM patients and 13 normal controls (donor hearts). Results: Integrated omics analysis revealed alterations in a wide array of biochemical pathways with major dysregulation in fatty acid metabolism, reduction of acylcarnitines, and accumulation of free fatty acids. HCM hearts showed evidence of global energetic decompensation manifested by a decrease in high energy phosphate metabolites [ATP, ADP, and phosphocreatine (PCr)] and a reduction in mitochondrial genes involved in creatine kinase and ATP synthesis. Accompanying these metabolic derangements, electron microscopy showed an increased fraction of severely damaged mitochondria with reduced cristae density, coinciding with reduced citrate synthase (CS) activity and mitochondrial oxidative respiration. These mitochondrial abnormalities were associated with elevated reactive oxygen species (ROS) and reduced antioxidant defenses. However, despite significant mitochondrial injury, HCM hearts failed to upregulate mitophagic clearance. Conclusions: Overall, our findings suggest that perturbed metabolic signaling and mitochondrial dysfunction are common pathogenic mechanisms in patients with HCM. These results highlight potential new drug targets for attenuation of the clinical disease through improving metabolic function and reducing mitochondrial injury.

  View details for DOI 10.1161/CIRCULATIONAHA.121.053575

  View details for PubMedID 34672721

• RARG variant predictive of doxorubicin-induced cardiotoxicity identifies a cardioprotective therapy. Cell stem cell Magdy, T., Jiang, Z., Jouni, M., Fonoudi, H., Lyra-Leite, D., Jung, G., Romero-Tejeda, M., Kuo, H., Fetterman, K. A., Gharib, M., Burmeister, B. T., Zhao, M., Sapkota, Y., Ross, C. J., Carleton, B. C., Bernstein, D., Burridge, P. W. 2021

  Abstract

  Doxorubicin is an anthracycline chemotherapy agent effective in treating a wide range of malignancies, but its use is limited by dose-dependent cardiotoxicity. A recent genome-wide association study identified a SNP (rs2229774) in retinoic acid receptor-gamma (RARG) as statistically associated with increased risk of anthracycline-induced cardiotoxicity. Here, we show that human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from patients with rs2229774 and who suffered doxorubicin-induced cardiotoxicity (DIC) are more sensitive to doxorubicin. We determine that the mechanism of this RARG variant effect is mediated via suppression of topoisomerase 2beta (TOP2B) expression and activation of the cardioprotective extracellular regulated kinase (ERK) pathway. We use patient-specific hiPSC-CMs as a drug discovery platform, determining that the RARG agonist CD1530 attenuates DIC, and we confirm this cardioprotective effect in an established invivo mouse model of DIC. This study provides a rationale for clinical prechemotherapy genetic screening for rs2229774 and a foundation for the clinical use of RARG agonist treatment to protect cancer patients from DIC.

  View details for DOI 10.1016/j.stem.2021.08.006

  View details for PubMedID 34525346

• Clinical and hemodynamic characteristics of the pediatric failing Fontan. The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation Dykes, J. C., Rosenthal, D. N., Bernstein, D., McElhinney, D. B., Chrisant, M. R., Daly, K. P., Ameduri, R. K., Knecht, K., Richmond, M. E., Lin, K. Y., Urschel, S., Simmonds, J., Simpson, K. E., Albers, E. L., Khan, A., Schumacher, K., Almond, C. S., Chen, S., Pediatric Heart Transplant Society 2021

  Abstract

  AIM: To describe the clinical and hemodynamic characteristics of Fontan failure in children listed for heart transplant.METHODS: In a nested study of the Pediatric Heart Transplant Society, 16 centers contributed information on Fontan patients listed for heart transplant between 2005and 2013.Patients were classified into four mutually exclusive phenotypes: Fontan with abnormal lymphatics (FAL), Fontan with reduced systolic function (FRF), Fontan with preserved systolic function (FPF), and Fontan with "normal" hearts (FNH). Primary outcome was waitlist and post-transplant mortality.RESULTS: 177 children listed for transplant were followed over a median 13 (IQR 4-31) months, 84 (47%) were FAL, 57 (32%) FRF, 22 (12%) FNH, and 14 (8%) FPF. Hemodynamic characteristics differed between the 4 groups: Fontan pressure (FP) was most elevated with FPF (median 22, IQR 18-23, mmHg) and lowest with FAL (16, 14-20, mmHg); cardiac index (CI) was lowest with FRF (2.8, 2.3-3.4, L/min/m2). In the entire cohort, 66% had FP >15 mmHg, 21% had FP >20 mmHg, and 10% had CI <2.2 L/min/m2. FRF had the highest risk of waitlist mortality (21%) and FNH had the highest risk of post-transplant mortality (36%).CONCLUSIONS: Elevated Fontan pressure is more common than low cardiac output in pediatric failing Fontan patients listed for transplant. Subtle hemodynamic differences exist between the various phenotypes of pediatric Fontan failure. Waitlist and post-transplant mortality risks differ by phenotype.

  View details for DOI 10.1016/j.healun.2021.07.017

  View details for PubMedID 34412962

• Hypertrophic cardiomyopathy beta-cardiac myosin mutation (P710R) leads to hypercontractility by disrupting super relaxed state. Proceedings of the National Academy of Sciences of the United States of America Vander Roest, A. S., Liu, C., Morck, M. M., Kooiker, K. B., Jung, G., Song, D., Dawood, A., Jhingran, A., Pardon, G., Ranjbarvaziri, S., Fajardo, G., Zhao, M., Campbell, K. S., Pruitt, B. L., Spudich, J. A., Ruppel, K. M., Bernstein, D. 2021; 118 (24)

  Abstract

  Hypertrophic cardiomyopathy (HCM) is the most common inherited form of heart disease, associated with over 1,000 mutations, many in beta-cardiac myosin (MYH7). Molecular studies of myosin with different HCM mutations have revealed a diversity of effects on ATPase and load-sensitive rate of detachment from actin. It has been difficult to predict how such diverse molecular effects combine to influence forces at the cellular level and further influence cellular phenotypes. This study focused on the P710R mutation that dramatically decreased in vitro motility velocity and actin-activated ATPase, in contrast to other MYH7 mutations. Optical trap measurements of single myosin molecules revealed that this mutation reduced the step size of the myosin motor and the load sensitivity of the actin detachment rate. Conversely, this mutation destabilized the super relaxed state in longer, two-headed myosin constructs, freeing more heads to generate force. Micropatterned human induced pluripotent derived stem cell (hiPSC)-cardiomyocytes CRISPR-edited with the P710R mutation produced significantly increased force (measured by traction force microscopy) compared with isogenic control cells. The P710R mutation also caused cardiomyocyte hypertrophy and cytoskeletal remodeling as measured by immunostaining and electron microscopy. Cellular hypertrophy was prevented in the P710R cells by inhibition of ERK or Akt. Finally, we used a computational model that integrated the measured molecular changes to predict the measured traction forces. These results confirm a key role for regulation of the super relaxed state in driving hypercontractility in HCM with the P710R mutation and demonstrate the value of a multiscale approach in revealing key mechanisms of disease.

  View details for DOI 10.1073/pnas.2025030118

  View details for PubMedID 34117120

• Gain of Function Mutations in Latent Membrane Protein 1 of Epstein Barr Virus are Associated with Increased Risk of Post-Transplant Lymphoproliferative Disorder Martinez, O. M., Krams, S. M., Robien, M., Lapasaran, M., Arvedson, M., Weinberg, K., Boyd, S., Armstrong, B., Twist, C., Gratzinger, D., Tan, B., Trickey, A., Sever, M., Brown, M., Bernstein, D., Esquivel, C. O. WILEY. 2021: 349-350

  View details for Web of Science ID 000705310101135

• Impact of institutional routine surveillance endomyocardial biopsy frequency in the first year on rejection and graft survival in pediatric heart transplantation. Pediatric transplantation Duong, S. Q., Zhang, Y., Hall, M., Hollander, S. A., Thurm, C. W., Bernstein, D., Feingold, B., Godown, J., Almond, C. 2021: e14035

  Abstract

  BACKGROUND: Routine surveillance biopsy (RSB) is performed to detect asymptomatic acute rejection (AR) after heart transplantation (HT). Variation in pediatric RSB across institutions is high. We examined center-based variation in RSB and its relationship to graft loss, AR, coronary artery vasculopathy (CAV), and cost of care during the first year post-HT.METHODS: We linked the Pediatric Health Information System (PHIS) and Scientific Registry of Transplant Recipients (SRTR, 2002-2016), including all primary-HT aged 0-21years. We characterized centers by RSB frequency (defined as median biopsies performed among recipients aged ≥12months without rejection in the first year). We adjusted for potential confounders and center effects with mixed-effects regression analysis.RESULTS: We analyzed 2867 patients at 29 centers. After adjusting for patient and center differences, increasing RSB frequency was associated with diagnosed AR (OR 1.15 p=0.004), a trend toward treated AR (OR 1.09 p=0.083), and higher hospital-based cost (US$390315 vs. $313248, p<0.001) but no difference in graft survival (HR 1.00, p=0.970) or CAV (SHR 1.04, p=0.757) over median follow-up 3.9years. Center RSB-frequency threshold of ≥2/year was associated with increased unadjusted rates of treated AR, but no association was found at thresholds greater than this.CONCLUSION: Center RSB frequency is positively associated with increased diagnosis of AR at 1year post-HT. Graft survival and CAV appear similar at medium-term follow-up. We speculate that higher frequency RSB centers may have increased detection of clinically less important AR, though further study of the relationship between center RSB frequency and differences in treated AR is necessary.

  View details for DOI 10.1111/petr.14035

  View details for PubMedID 34003559

• Improving Right Ventricular Function by Increasing BMP Signaling with FK506. American journal of respiratory cell and molecular biology Boehm, M., Tian, X., Ali, M. K., Mao, Y., Ichimura, K., Zhao, M., Kuramoto, K., Dannewitz Prosseda, S., Fajardo, G., Dufva, M. J., Qin, X., Kheyfets, V. O., Bernstein, D., Reddy, S., Metzger, R. J., Zamanian, R. T., Haddad, F., Spiekerkoetter, E. 2021

  Abstract

  Right Ventricular (RV) function is the predominant determinant of survival in patients suffering from pulmonary arterial hypertension (PAH). In pre-clinical models, pharmacological activation of bone morphogenetic protein (BMP) signaling with FK506 (Tacrolimus) improved RV function by decreasing RV afterload. FK506 therapy further stabilized three end-stage PAH patients. Whether FK506 has direct effects on the pressure overloaded RV is yet unknown. We hypothesized that increasing cardiac BMP signaling with FK506 improves RV structure and function in a model of fixed RV afterload after pulmonary artery banding (PAB). Direct cardiac effects of FK506 on the microvasculature and RV fibrosis were studied after surgical PAB in wildtype and heterozygous Bmpr2 mutant mice. Right ventricular function and strain were assessed longitudinally via cardiac magnetic resonance (CMR) imaging during continuous FK506 infusion. Genetic lineage tracing of endothelial cells (ECs) was performed to assess the contribution of ECs to fibrosis. Molecular mechanistic studies were performed in human cardiac fibroblasts (hCFs) and endothelial cells. In mice, low BMP signaling in the RV exaggerated PAB-induced RV fibrosis. FK506 therapy restored cardiac BMP signaling, reduced RV fibrosis in a BMP-dependent manner independent from its immunosuppressive effect, preserved RV capillarization and improved RV function and strain over the time-course of disease. Endothelial mesenchymal transition was a rare event and did not significantly contribute to cardiac fibrosis after PAB. Mechanistically, FK506 required ALK1 in hCFs as BMPR2 co-receptor to reduce TGFbeta1-induced proliferation and collagen production. Our study demonstrates that increasing cardiac BMP signaling with FK506 improves RV structure and function independent from its previously described beneficial effects on pulmonary vascular remodeling.

  View details for DOI 10.1165/rcmb.2020-0528OC

  View details for PubMedID 33938785

• Impact of Institutional Routine Endomyocardial Surveillance Biopsy Practices on Rejection and Graft Survival in Pediatric Heart Transplantation Duong, S. Q., Zhang, Y., Hall, M., Hollander, S., Thurm, C. W., Bernstein, D., Feingold, B., Godown, J., Almond, C. ELSEVIER SCIENCE INC. 2021: S121–S122

  View details for Web of Science ID 000631254400265

• Induction and Increased Risk of Infections in Pediatric Fontan Patients after Heart Transplantation Ahmed, H., Lee, J., Bernstein, D., Weinberg, K., Rosenthal, D. N., Lee, D., Barkoff, L., Hollander, S., Chen, S. ELSEVIER SCIENCE INC. 2021: S120

  View details for Web of Science ID 000631254400262

• Molecular Mechanisms and Cellular Models of Hypertrophic Cardiomyopathy: Insights from a Surprising Mutation Vander Roest, A. S., Liu, C., Kooiker, K. B., Morck, M. M., Pruitt, B., Campbell, K. S., Ruppel, K., Spudich, J. A., Bernstein, D. CELL PRESS. 2021: 253A

  View details for Web of Science ID 000629601401473

• Transcriptomic and Functional Analyses of Mitochondrial Dysfunction in Pressure Overload-Induced Right Ventricular Failure. Journal of the American Heart Association Hwang, H. V., Sandeep, N., Nair, R. V., Hu, D., Zhao, M., Lan, I. S., Fajardo, G., Matkovich, S. J., Bernstein, D., Reddy, S. 2021: e017835

  Abstract

  Background In complex congenital heart disease patients such as those with tetralogy of Fallot, the right ventricle (RV) is subject to pressure overload, leading to RV hypertrophy and eventually RV failure. The mechanisms that promote the transition from stable RV hypertrophy to RV failure are unknown. We evaluated the role of mitochondrial bioenergetics in the development of RV failure. Methods and Results We created a murine model of RV pressure overload by pulmonary artery banding and compared with sham-operated controls. Gene expression by RNA-sequencing, oxidative stress, mitochondrial respiration, dynamics, and structure were assessed in pressure overload-induced RV failure. RV failure was characterized by decreased expression of electron transport chain genes and mitochondrial antioxidant genes (aldehyde dehydrogenase 2 and superoxide dismutase 2) and increased expression of oxidant stress markers (heme oxygenase, 4-hydroxynonenal). The activities of all electron transport chain complexes decreased with RV hypertrophy and further with RV failure (oxidative phosphorylation: sham 552.3±43.07 versus RV hypertrophy 334.3±30.65 versus RV failure 165.4±36.72pmol/(s*mL), P<0.0001). Mitochondrial fission protein DRP1 (dynamin 1-like) trended toward an increase, while MFF (mitochondrial fission factor) decreased and fusion protein OPA1 (mitochondrial dynamin like GTPase) decreased. In contrast, transcription of electron transport chain genes increased in the left ventricle of RV failure. Conclusions Pressure overload-induced RV failure is characterized by decreased transcription and activity of electron transport chain complexes and increased oxidative stress which are associated with decreased energy generation. An improved understanding of the complex processes of energy generation could aid in developing novel therapies to mitigate mitochondrial dysfunction and delay the onset of RV failure.

  View details for DOI 10.1161/JAHA.120.017835

  View details for PubMedID 33522250

• Dach1 Extends Artery Networks and Protects Against Cardiac Injury. Circulation research Raftrey, B., Williams, I. M., Rios Coronado, P. E., Fan, X., Chang, A. H., Zhao, M., Roth, R. K., Trimm, E., Racelis, R., D'Amato, G., Phansalkar, R., Nguyen, A., Chai, T., Gonzalez, K. M., Zhang, Y., Ang, L. T., Loh, K., Bernstein, D., Red-Horse, K. 2021

  Abstract

  Rationale: Coronary artery disease (CAD) is the leading cause of death worldwide, but there are currently no methods to stimulate artery growth or regeneration in diseased hearts. Studying how arteries are built during development could illuminate strategies for re-building these vessels during ischemic heart disease. We previously found that Dach1 deletion in mouse embryos resulted in small coronary arteries. However, it was not known whether Dach1 gain-of-function would be sufficient to increase arterial vessels and whether this could benefit injury responses. Objective: We investigated how Dach1 overexpression in endothelial cells affected transcription and artery differentiation, and how it influenced recovery from myocardial infarction (MI). Methods and Results: Dach1 was genetically overexpressed in coronary endothelial cells (ECs) in either developing or adult hearts using ApjCreER. This increased the length and number of arterial end branches expanded arteries during development, in both the heart and retina, by inducing capillary ECs to differentiate and contribute to growing arteries. Single-cell RNA sequencing (scRNAseq) of ECs undergoing Dach1-induced arterial specification indicated that it potentiated normal artery differentiation, rather than functioning as a master regulator of artery cell fate. ScRNAseq also showed that normal arterial differentiation is accompanied by repression of lipid metabolism genes, which were also repressed by Dach1. In adults, Dach1 overexpression did not cause a statistically significant change artery structure prior to injury, but increased the number of perfused arteries in the injury zone post-MI. Conclusions: Our data demonstrate that increasing Dach1 is a novel method for driving artery specification and extending arterial branches, which could be explored as a means of mitigating the effects of CAD.

  View details for DOI 10.1161/CIRCRESAHA.120.318271

  View details for PubMedID 34383559

• β2-Adrenergic Signaling Modulates Mitochondrial Function and Morphology in Skeletal Muscle in Response to Aerobic Exercise. Cells Azevedo Voltarelli, V. n., Coronado, M. n., Gonçalves Fernandes, L. n., Cruz Campos, J. n., Jannig, P. R., Batista Ferreira, J. C., Fajardo, G. n., Chakur Brum, P. n., Bernstein, D. n. 2021; 10 (1)

  Abstract

  The molecular mechanisms underlying skeletal muscle mitochondrial adaptations induced by aerobic exercise (AE) are not fully understood. We have previously shown that AE induces mitochondrial adaptations in cardiac muscle, mediated by sympathetic stimulation. Since direct sympathetic innervation of neuromuscular junctions influences skeletal muscle homeostasis, we tested the hypothesis that β2-adrenergic receptor (β2-AR)-mediated sympathetic activation induces mitochondrial adaptations to AE in skeletal muscle. Male FVB mice were subjected to a single bout of AE on a treadmill (80% Vmax, 60 min) under β2-AR blockade with ICI 118,551 (ICI) or vehicle, and parameters of mitochondrial function and morphology/dynamics were evaluated. An acute bout of AE significantly increased maximal mitochondrial respiration in tibialis anterior (TA) isolated fiber bundles, which was prevented by β2-AR blockade. This increased mitochondrial function after AE was accompanied by a change in mitochondrial morphology towards fusion, associated with increased Mfn1 protein expression and activity. β2-AR blockade fully prevented the increase in Mfn1 activity and reduced mitochondrial elongation. To determine the mechanisms involved in mitochondrial modulation by β2-AR activation in skeletal muscle during AE, we used C2C12 myotubes, treated with the non-selective β-AR agonist isoproterenol (ISO) in the presence of the specific β2-AR antagonist ICI or during protein kinase A (PKA) and Gαi protein blockade. Our in vitro data show that β-AR activation significantly increases mitochondrial respiration in myotubes, and this response was dependent on β2-AR activation through a Gαs-PKA signaling cascade. In conclusion, we provide evidence for AE-induced β2-AR activation as a major mechanism leading to alterations in mitochondria function and morphology/dynamics. β2-AR signaling is thus a key-signaling pathway that contributes to skeletal muscle plasticity in response to exercise.

  View details for DOI 10.3390/cells10010146

  View details for PubMedID 33450889

• Comparison of combined heart‒liver vs heart-only transplantation in pediatric and young adult Fontan recipients. The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation Sganga, D., Hollander, S. A., Vaikunth, S., Haeffele, C., Bensen, R., Navaratnam, M., McDonald, N., Profita, E., Maeda, K., Concepcion, W., Bernstein, D., Chen, S. 2020

  Abstract

  BACKGROUND: Indications for a heart‒liver transplantation (HLT) for Fontan recipients are not well defined. We compared listing characteristics, post-operative complications, and post-transplant outcomes of Fontan recipients who underwent HLT with those of patients who underwent heart-only transplantation (HT). We hypothesized that patients who underwent HLT have increased post-operative complications but superior survival outcomes compared with patients who underwent HT.METHODS: We performed a retrospective review of Fontan recipients who underwent HLT or HT at a single institution. Characteristics at the time of listing, including the extent of liver disease determined by laboratory, imaging, and biopsy data, were compared. Post-operative complications were assessed, and the Kaplan‒Meier survival method was used to compare post-transplant survival. Univariate regression analyses were performed to identify the risk factors for increased mortality and morbidity among patients who underwent HT.RESULTS: A total of 47 patients (9 for HLT, 38 for HT) were included. Patients who underwent HLT were older, were more likely to be on dual inotrope therapy, and had evidence of worse liver disease. Whereas ischemic time was longer for the group who underwent HLT, post-operative complications were similar. Over a median post-transplant follow-up of 17 (interquartile range: 5-52) months, overall mortality for the cohort was 17%; only 1 patient who underwent HLT died (11%) vs 7 patients who underwent HT (18%) (p = 0.64). Among patients who underwent HT, cirrhosis on pre-transplant imaging was associated with worse outcomes.CONCLUSIONS: Despite greater inotrope need and more severe liver disease at the time of listing, Fontan recipients undergoing HLT have post-transplant outcomes comparable with those of patients undergoing HT. HLT may offer a survival benefit for Fontan recipients with liver disease.

  View details for DOI 10.1016/j.healun.2020.12.008

  View details for PubMedID 33485775

• Association of Damaging Variants in Genes With Increased Cancer Risk Among Patients With Congenital Heart Disease. JAMA cardiology Morton, S. U., Shimamura, A., Newburger, P. E., Opotowsky, A. R., Quiat, D., Pereira, A. C., Jin, S. C., Gurvitz, M., Brueckner, M., Chung, W. K., Shen, Y., Bernstein, D., Gelb, B. D., Giardini, A., Goldmuntz, E., Kim, R. W., Lifton, R. P., Porter, G. A., Srivastava, D., Tristani-Firouzi, M., Newburger, J. W., Seidman, J. G., Seidman, C. E. 2020

  Abstract

  Importance: Patients with congenital heart disease (CHD), the most common birth defect, have increased risks for cancer. Identification of the variables that contribute to cancer risk is essential for recognizing patients with CHD who warrant longitudinal surveillance and early interventions.Objective: To compare the frequency of damaging variants in cancer risk genes among patients with CHD and control participants and identify associated clinical variables in patients with CHD who have cancer risk variants.Design, Setting, and Participants: This multicenter case-control study included participants with CHD who had previously been recruited to the Pediatric Cardiac Genomics Consortium based on presence of structural cardiac anomaly without genetic diagnosis at the time of enrollment. Permission to use published sequencing data from unaffected adult participants was obtained from 2 parent studies. Data were collected for this study from December 2010 to April 2019.Exposures: Presence of rare (allele frequency, <1*10-5) loss-of-function (LoF) variants in cancer risk genes.Main Outcomes and Measures: Frequency of LoF variants in cancer risk genes (defined in the Catalogue of Somatic Mutations in Cancer-Cancer Gene Consensus database), were statistically assessed by binomial tests in patients with CHD and control participants.Results: A total of 4443 individuals with CHD (mean [range] age, 13.0 [0-84] years; 2225 of 3771 with reported sex [59.0%] male) and 9808 control participants (mean [range] age, 52.1 [1-92] years; 4967 of 9808 [50.6%] male) were included. The frequency of LoF variants in regulatory cancer risk genes was significantly higher in patients with CHD than control participants (143 of 4443 [3.2%] vs 166 of 9808 [1.7%]; odds ratio [OR], 1.93 [95% CI, 1.54-2.42]; P=1.38*10-12), and among CHD genes previously associated with cancer risk (58 of 4443 [1.3%] vs 18 of 9808 [0.18%]; OR, 7.2 [95% CI, 4.2-12.2]; P<2.2*10-16). The LoF variants were also nominally increased in 14 constrained cancer risk genes with high expression in the developing heart. Seven of these genes (ARHGEF12, CTNNB1, LPP, MLLT4, PTEN, TCF12, and TFRC) harbored LoF variants in multiple patients with unexplained CHD. The highest rates for LoF variants in cancer risk genes occurred in patients with CHD and extracardiac anomalies (248 of 1482 individuals [16.7%]; control: 1099 of 9808 individuals [11.2%]; OR, 1.59 [95% CI, 1.37-1.85]; P=1.3*10-10) and/or neurodevelopmental delay (209 of 1393 individuals [15.0%]; control: 1099 of 9808 individuals [11.2%]; OR, 1.40 [95% CI, 1.19-1.64]; P=9.6*10-6).Conclusions and Relevance: Genotypes of CHD may account for increased cancer risks. In this cohort, damaging variants were prominent in the 216 genes that predominantly encode regulatory proteins. Consistent with their fundamental developmental functions, patients with CHD and damaging variants in these genes often had extracardiac manifestations. These data may also implicate cancer risk genes that are repeatedly varied in patients with unexplained CHD as CHD genes.

  View details for DOI 10.1001/jamacardio.2020.4947

  View details for PubMedID 33084842

• Patient-Specific Induced Pluripotent Stem Cells Implicate Intrinsic Impaired Contractility in Hypoplastic Left Heart Syndrome. Circulation Paige, S. L., Galdos, F. X., Lee, S., Chin, E. T., Ranjbarvaziri, S., Feyen, D. A., Darsha, A. K., Xu, S., Ryan, J. A., Beck, A. L., Qureshi, M. Y., Miao, Y., Gu, M., Bernstein, D., Nelson, T. J., Mercola, M., Rabinovitch, M., Ashley, E. A., Parikh, V. N., Wu, S. M. 2020; 142 (16): 1605–8

  View details for DOI 10.1161/CIRCULATIONAHA.119.045317

  View details for PubMedID 33074758

• GATA6 mutations in hiPSCs inform mechanisms for maldevelopment of the heart, pancreas, and diaphragm. eLife Sharma, A., Wasson, L. K., Willcox, J. A., Morton, S. U., Gorham, J. M., DeLaughter, D. M., Neyazi, M., Schmid, M., Agarwal, R., Jang, M. Y., Toepfer, C. N., Ward, T., Kim, Y., Pereira, A. C., DePalma, S. R., Tai, A., Kim, S., Conner, D., Bernstein, D., Gelb, B. D., Chung, W. K., Goldmuntz, E., Porter, G., Tristani-Firouzi, M., Srivastava, D., Seidman, J. G., Seidman, C. E. 2020; 9

  Abstract

  Damaging GATA6 variants cause cardiac outflow tract defects, sometimes with pancreatic and diaphragmic malformations. To define molecular mechanisms for these diverse developmental defects, we studied transcriptional and epigenetic responses to GATA6 loss of function and missense variants during cardiomyocyte differentiation of isogenic human induced pluripotent stem cells. We show that GATA6 is a pioneer factor in cardiac development, regulating SMYD1 that activates HAND2, and KDR that with HAND2 orchestrates outflow tract formation. Loss of function variants perturbed cardiac genes and also endoderm lineage genes that direct PDX1 expression and pancreatic development. Remarkably, an exon 4 GATA6 missense variant, highly associated with extra-cardiac malformations, caused ectopic pioneer activities, profoundly diminishing GATA4, FOXA1/2 and PDX1 expression and increasing normal retinoic acid signaling that promotes diaphragm development. These aberrant epigenetic and transcriptional signatures illuminate the molecular mechanisms for cardiovascular malformations, pancreas and diaphragm dysgenesis that arise in patients with distinct GATA6 variants.

  View details for DOI 10.7554/eLife.53278

  View details for PubMedID 33054971

• Noncanonical WNT Activation in Human Right Ventricular Heart Failure FRONTIERS IN CARDIOVASCULAR MEDICINE Edwards, J. J., Brandimarto, J., Hu, D., Jeong, S., Yucel, N., Li, L., Bedi, K. C., Wada, S., Murashige, D., Hwang, H. V., Zhao, M., Margulies, K. B., Bernstein, D., Reddy, S., Arany, Z. 2020; 7: 582407

  Abstract

  Background: No medical therapies exist to treat right ventricular (RV) remodeling and RV failure (RVF), in large part because molecular pathways that are specifically activated in pathologic human RV remodeling remain poorly defined. Murine models have suggested involvement of Wnt signaling, but this has not been well-defined in human RVF. Methods: Using a candidate gene approach, we sought to identify genes specifically expressed in human pathologic RV remodeling by assessing the expression of 28 WNT-related genes in the RVs of three groups: explanted nonfailing donors (NF, n = 29), explanted dilated and ischemic cardiomyopathy, obtained at the time of cardiac transplantation, either with preserved RV function (pRV, n = 78) or with RVF (n = 35). Results: We identified the noncanonical WNT receptor ROR2 as transcriptionally strongly upregulated in RVF compared to pRV and NF (Benjamini-Hochberg adjusted P < 0.05). ROR2 protein expression correlated linearly to mRNA expression (R2 = 0.41, P = 8.1 × 10-18) among all RVs, and to higher right atrial to pulmonary capillary wedge ratio in RVF (R2 = 0.40, P = 3.0 × 10-5). Utilizing Masson's trichrome and ROR2 immunohistochemistry, we identified preferential ROR2 protein expression in fibrotic regions by both cardiomyocytes and noncardiomyocytes. We compared RVF with high and low ROR2 expression, and found that high ROR2 expression was associated with increased expression of the WNT5A/ROR2/Ca2+ responsive protease calpain-μ, cleavage of its target FLNA, and FLNA phosphorylation, another marker of activation downstream of ROR2. ROR2 protein expression as a continuous variable, correlated strongly to expression of calpain-μ (R2 = 0.25), total FLNA (R2 = 0.67), calpain cleaved FLNA (R2 = 0.32) and FLNA phosphorylation (R2 = 0.62, P < 0.05 for all). Conclusion: We demonstrate robust reactivation of a fetal WNT gene program, specifically its noncanonical arm, in human RVF characterized by activation of ROR2/calpain mediated cytoskeleton protein cleavage.

  View details for DOI 10.3389/fcvm.2020.582407

  View details for Web of Science ID 000579825800001

  View details for PubMedID 33134326

  View details for PubMedCentralID PMC7575695

• Diagnosis and treatment of right ventricular dysfunction in congenital heart disease CARDIOVASCULAR DIAGNOSIS AND THERAPY Santens, B., Van de Bruaene, A., De Meester, P., D'Alto, M., Reddy, S., Bernstein, D., Koestenberger, M., Hansmann, G., Budts, W. 2020; 10 (5): 1625–45

  Abstract

  Right ventricular (RV) function is important for clinical status and outcomes in children and adults with congenital heart disease (CHD). In the normal RV, longitudinal systolic function is the major contributor to global RV systolic function. A variety of factors contribute to RV failure including increased pressure- or volume-loading, electromechanical dyssynchrony, increased myocardial fibrosis, abnormal coronary perfusion, restricted filling capacity and adverse interactions between left ventricle (LV) and RV. We discuss the different imaging techniques both at rest and during exercise to define and detect RV failure. We identify the most important biomarkers for risk stratification in RV dysfunction, including abnormal NYHA class, decreased exercise capacity, low blood pressure, and increased levels of NTproBNP, troponin T, galectin-3 and growth differentiation factor 15. In adults with CHD (ACHD), fragmented QRS is independently associated with heart failure (HF) symptoms and impaired ventricular function. Furthermore, we discuss the different HF therapies in CHD but given the broad clinical spectrum of CHD, it is important to treat RV failure in a disease-specific manner and based on the specific alterations in hemodynamics. Here, we discuss how to detect and treat RV dysfunction in CHD in order to prevent or postpone RV failure.

  View details for DOI 10.21037/cdt-20-370

  View details for Web of Science ID 000582467900038

  View details for PubMedID 33224777

  View details for PubMedCentralID PMC7666946

• Stanford University School of Medicine ACADEMIC MEDICINE Bernstein, D., Irvine, C. A., Basaviah, P., Lau, J. N., Austin, B., Utz, P. J., Gesundheit, N. 2020; 95 (9): S50–S53

  View details for DOI 10.1097/ACM.0000000000003493

  View details for Web of Science ID 000619186200013

  View details for PubMedID 33626643

• 4HNE Impairs Myocardial Bioenergetics in Congenital Heart DiseaseInduced Right Ventricular Failure. Circulation Hwang, H. V., Sandeep, N., Paige, S. L., Ranjbarvaziri, S., Hu, D., Zhao, M., Lan, I. S., Coronado, M., Kooiker, K. B., Wu, S. M., Fajardo, G., Bernstein, D., Reddy, S. 2020

  Abstract

  Background: In patients with complex congenital heart disease, such as those with tetralogy of Fallot, the right ventricle (RV) is subject to pressure overload stress, leading to RV hypertrophy and eventually RV failure. The role of lipid peroxidation, a potent form of oxidative stress, in mediating RV hypertrophy and failure in congenital heart disease is unknown. Methods: Lipid peroxidation and mitochondrial function and structure were assessed in RV myocardium collected from patients with RV hypertrophy with normal RV systolic function (RV FAC 47.3±3.8%) and in patients with RV failure showing decreased RV systolic function (RV FAC 26.6±3.1%). The mechanism of the effect of lipid peroxidation, mediated by 4-hydroxynonenal (4HNE; a byproduct of lipid peroxidation) on mitochondrial function and structure was assessed in HL1 murine cardiomyocytes and human induced pluripotent stem cellderived cardiomyocytes. Results: RV failure was characterized by an increase in 4HNE adduction of metabolic and mitochondrial proteins (16/27 identified proteins), in particular electron transport chain proteins. Sarcomeric (myosin) and cytoskeletal proteins (desmin, tubulin) also underwent 4HNEadduction. RV failure showed lower oxidative phosphorylation [moderate RV hypertrophy 287.6±19.75 vs. RV failure 137.8±11.57 pmol/(sec*ml), p=0.0004], and mitochondrial structural damage. Using a cell model, we show that 4HNE decreases cell number and oxidative phosphorylation (control 388.1±23.54 vs. 4HNE 143.7±11.64 pmol/(sec*ml), p<0.0001). Carvedilol, a known antioxidant did not decrease 4HNE adduction of metabolic and mitochondrial proteins and did not improve oxidative phosphorylation. Conclusions: Metabolic, mitochondrial, sarcomeric and cytoskeletal proteins are susceptible to 4HNE-adduction in patients with RV failure. 4HNE decreases mitochondrial oxygen consumption by inhibiting electron transport chain complexes. Carvedilol did not improve the 4HNE-mediated decrease in oxygen consumption. Strategies to decrease lipid peroxidation could improve mitochondrial energy generation and cardiomyocyte survival and improve RV failure in patients with congenital heart disease.

  View details for DOI 10.1161/CIRCULATIONAHA.120.045470

  View details for PubMedID 32806952

• De Novo Damaging Variants, Clinical Phenotypes, and Post-Operative Outcomes in Congenital Heart Disease. Circulation. Genomic and precision medicine Boskovski, M. T., Homsy, J., Nathan, M., Sleeper, L. A., Morton, S., Manheimer, K. B., Tai, A., Gorham, J., Lewis, M., Swartz, M., Alfieris, G. M., Bacha, E. A., Karimi, M., Meyer, D., Nguyen, K., Bernstein, D., Romano-Adesman, A., Porter, G. A., Goldmuntz, E., Chung, W. K., Srivastava, D., Kaltman, J. R., Tristani-Firouzi, M., Lifton, R., Roberts, A. E., Gaynor, J. W., Gelb, B. D., Kim, R., Seidman, J. G., Brueckner, M., Mayer, J. E., Newburger, J. W., Seidman, C. E. 2020; 13 (4): e002836

  Abstract

  BACKGROUND: De novo genic and copy number variants are enriched in patients with congenital heart disease, particularly those with extra-cardiac anomalies. The impact of de novo damaging variants on outcomes following cardiac repair is unknown.METHODS: We studied 2517 patients with congenital heart disease who had undergone whole-exome sequencing as part of the CHD GENES study (Congenital Heart Disease Genetic Network).RESULTS: Two hundred ninety-four patients (11.7%) had clinically significant de novo variants. Patients with de novo damaging variants were 2.4 times more likely to have extra-cardiac anomalies (P=5.63*10-12). In 1268 patients (50.4%) who had surgical data available and underwent open-heart surgery exclusive of heart transplantation as their first operation, we analyzed transplant-free survival following the first operation. Median follow-up was 2.65 years. De novo variants were associated with worse transplant-free survival (hazard ratio, 3.51; P=5.33*10-04) and longer times to final extubation (hazard ratio, 0.74; P=0.005). As de novo variants had a significant interaction with extra-cardiac anomalies for transplant-free survival (P=0.003), de novo variants conveyed no additional risk for transplant-free survival for patients with these anomalies (adjusted hazard ratio, 1.96; P=0.06). By contrast, de novo variants in patients without extra-cardiac anomalies were associated with worse transplant-free survival during follow-up (hazard ratio, 11.21; P=1.61*10-05) than that of patients with no de novo variants. Using agnostic machine-learning algorithms, we identified de novo copy number variants at 15q25.2 and 15q11.2 as being associated with worse transplant-free survival and 15q25.2, 22q11.21, and 3p25.2 as being associated with prolonged time to final extubation.CONCLUSIONS: In patients with congenital heart disease undergoing open-heart surgery, de novo variants were associated with worse transplant-free survival and longer times on the ventilator. De novo variants were most strongly associated with adverse outcomes among patients without extra-cardiac anomalies, suggesting a benefit for preoperative genetic testing even when genetic abnormalities are not suspected during routine clinical practice. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01196182.

  View details for DOI 10.1161/CIRCGEN.119.002836

  View details for PubMedID 32812804

• Hypertrophic Cardiomyopathy, a Disease of Altered Cardiac Energetics Ranjbarvaziri, S., Ellenberger, M., Kooiker, K., Fajardo, G., Zhao, M., Schroer, A., Woo, Y. Y., Ruppel, K. M., Spudich, J. A., Snyder, M., Contrepois, K., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2020

  View details for DOI 10.1161/res.127.suppl_1.235

  View details for Web of Science ID 000606541500028

• Noncanonical WNT Activation in Human Right Ventricular Heart Failure Edwards, J., Brandimarto, J. A., Hu, D., Yucel, N., Li, L., Jeong, S., Bedi, K. C., Hwang, H., Zhao, M., Margulies, K. B., Bernstein, D., Reddy, S., Arany, Z. LIPPINCOTT WILLIAMS & WILKINS. 2020

  View details for DOI 10.1161/res.127.suppl_1.237

  View details for Web of Science ID 000606541500030

• Genomic analyses implicate noncoding de novo variants in congenital heart disease. Nature genetics Richter, F., Morton, S. U., Kim, S. W., Kitaygorodsky, A., Wasson, L. K., Chen, K. M., Zhou, J., Qi, H., Patel, N., DePalma, S. R., Parfenov, M., Homsy, J., Gorham, J. M., Manheimer, K. B., Velinder, M., Farrell, A., Marth, G., Schadt, E. E., Kaltman, J. R., Newburger, J. W., Giardini, A., Goldmuntz, E., Brueckner, M., Kim, R., Porter, G. A., Bernstein, D., Chung, W. K., Srivastava, D., Tristani-Firouzi, M., Troyanskaya, O. G., Dickel, D. E., Shen, Y., Seidman, J. G., Seidman, C. E., Gelb, B. D. 2020

  Abstract

  A genetic etiology is identified for one-third of patients with congenital heart disease (CHD), with 8% of cases attributable to coding de novo variants (DNVs). To assess the contribution of noncoding DNVs to CHD, we compared genome sequences from 749 CHD probands and their parents with those from 1,611 unaffected trios. Neural network prediction of noncoding DNV transcriptional impact identified a burden of DNVs in individuals with CHD (n=2,238 DNVs) compared to controls (n=4,177; P=8.7*10-4). Independent analyses of enhancers showed an excess of DNVs in associated genes (27 genes versus 3.7 expected, P=1*10-5). We observed significant overlap between these transcription-based approaches (odds ratio (OR)=2.5, 95% confidence interval (CI) 1.1-5.0, P=5.4*10-3). CHD DNVs altered transcription levels in 5 of 31 enhancers assayed. Finally, we observed a DNV burden in RNA-binding-protein regulatory sites (OR=1.13, 95% CI 1.1-1.2, P=8.8*10-5). Our findings demonstrate an enrichment of potentially disruptive regulatory noncoding DNVs in a fraction of CHD at least as high as that observed for damaging coding DNVs.

  View details for DOI 10.1038/s41588-020-0652-z

  View details for PubMedID 32601476

• Transplant Monitoring and PTLD Detection with B Cell Receptor Repertoire Analysis in a Large Prospective Pediatric Cohort Jackson, K., Martinez, O., Krams, S., Robien, M., Lapasaran, M., Armstrong, B., Twist, C., Weinberg, K., Gratzinger, D., Tam, B., Sever, M., Brown, M., Bernstein, D., Esquivel, C., Boyd, S. D. WILEY. 2020: 321

  View details for Web of Science ID 000546629501153

• Waitlist Mortality in US Children Listed for Heart Transplant - Where are We Now? Power, A., Sweat, K. R., Hollander, S. A., Schmidt, J., Dykes, J. C., Profita, E. L., Bernstein, D., Almond, C. S. ELSEVIER SCIENCE INC. 2020: S86

  View details for Web of Science ID 000522637200187

• Outcomes of Heart and Combined Heart-Liver Transplant in Pediatric Fontan Patients Chen, S., Bensen, R., Profita, E., McDonald, N., Lui, G., Haeffele, C., Rosenthal, D. N., Bernstein, D., Maeda, K., Concepcion, W., Hollander, S. ELSEVIER SCIENCE INC. 2020: S453–S454

  View details for Web of Science ID 000522637203137

• Heightened Immune Response and Increased Risk of Infections in Pediatric Fontan Patients after Heart Transplantation Ahmed, H., Lee, J., Profita, E., Dykes, J., Hollander, S., Kaufman, B., Bernstein, D., Rosenthal, D. N., Barkoff, L., Lee, D., Chen, S. ELSEVIER SCIENCE INC. 2020: S452–S453

  View details for Web of Science ID 000522637203134

• Impact of High- vs. Low-Frequency Surveillance Endomyocardial Biopsy Strategy in Pediatric Heart Transplantation Duong, S., Hall, M., Hollander, S. A., Thurm, C., Bernstein, D., Feingold, B. D., Godown, J., Almond, C. ELSEVIER SCIENCE INC. 2020: S456

  View details for Web of Science ID 000522637203144

• Systems Analysis Implicates WAVE2Complex in the Pathogenesis ofDevelopmental Left-Sided ObstructiveHeart Defects. JACC. Basic to translational science Edwards, J. J., Rouillard, A. D., Fernandez, N. F., Wang, Z., Lachmann, A., Shankaran, S. S., Bisgrove, B. W., Demarest, B., Turan, N., Srivastava, D., Bernstein, D., Deanfield, J., Giardini, A., Porter, G., Kim, R., Roberts, A. E., Newburger, J. W., Goldmuntz, E., Brueckner, M., Lifton, R. P., Seidman, C. E., Chung, W. K., Tristani-Firouzi, M., Yost, H. J., Ma'ayan, A., Gelb, B. D. 2020; 5 (4): 376–86

  Abstract

  Genetic variants are the primary driver of congenital heart disease (CHD) pathogenesis. However, our ability to identify causative variants is limited. To identify causal CHD genes that are associated with specific molecular functions, the study used prior knowledge to filter de novo variants from 2,881 probands with sporadic severe CHD. This approach enabled the authors to identify an association between left ventricular outflow tract obstruction lesions and genes associated with the WAVE2 complex and regulation of small GTPase-mediated signal transduction. Using CRISPR zebrafish knockdowns, the study confirmed that WAVE2 complex proteins brk1, nckap1, and wasf2 and the regulators of small GTPase signaling cul3a and racgap1 are critical to cardiac development.

  View details for DOI 10.1016/j.jacbts.2020.01.012

  View details for PubMedID 32368696

• Metabolic Maturation Media Improve Physiological Function of Human iPSC-Derived Cardiomyocytes. Cell reports Feyen, D. A., McKeithan, W. L., Bruyneel, A. A., Spiering, S. n., Hörmann, L. n., Ulmer, B. n., Zhang, H. n., Briganti, F. n., Schweizer, M. n., Hegyi, B. n., Liao, Z. n., Pölönen, R. P., Ginsburg, K. S., Lam, C. K., Serrano, R. n., Wahlquist, C. n., Kreymerman, A. n., Vu, M. n., Amatya, P. L., Behrens, C. S., Ranjbarvaziri, S. n., Maas, R. G., Greenhaw, M. n., Bernstein, D. n., Wu, J. C., Bers, D. M., Eschenhagen, T. n., Metallo, C. M., Mercola, M. n. 2020; 32 (3): 107925

  Abstract

  Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) have enormous potential for the study of human cardiac disorders. However, their physiological immaturity severely limits their utility as a model system and their adoption for drug discovery. Here, we describe maturation media designed to provide oxidative substrates adapted to the metabolic needs of human iPSC (hiPSC)-CMs. Compared with conventionally cultured hiPSC-CMs, metabolically matured hiPSC-CMs contract with greater force and show an increased reliance on cardiac sodium (Na+) channels and sarcoplasmic reticulum calcium (Ca2+) cycling. The media enhance the function, long-term survival, and sarcomere structures in engineered heart tissues. Use of the maturation media made it possible to reliably model two genetic cardiac diseases: long QT syndrome type 3 due to a mutation in the cardiac Na+ channel SCN5A and dilated cardiomyopathy due to a mutation in the RNA splicing factor RBM20. The maturation media should increase the fidelity of hiPSC-CMs as disease models.

  View details for DOI 10.1016/j.celrep.2020.107925

  View details for PubMedID 32697997

• Advances in Pediatric Cardiology 2020. Current opinion in pediatrics Bernstein, D. n. 2020

  View details for DOI 10.1097/MOP.0000000000000944

  View details for PubMedID 32833800

• FK506 Requires ALK1 to Attenuate Stimulus-Induced Collagen Production in Human Cardiac Fibroblasts Ali, M., Tian, X., Boehm, M., Andruska, A. M., Zhao, M., Kuramoto, K., Bernstein, D., Metzger, R., Reddy, S., Spiekerkoetter, E. F. AMER THORACIC SOC. 2020

  View details for Web of Science ID 000556393501501

• Rare genetic variation at transcription factor binding sites modulates local DNA methylation profiles. PLoS genetics Martin-Trujillo, A. n., Patel, N. n., Richter, F. n., Jadhav, B. n., Garg, P. n., Morton, S. U., McKean, D. M., DePalma, S. R., Goldmuntz, E. n., Gruber, D. n., Kim, R. n., Newburger, J. W., Porter, G. A., Giardini, A. n., Bernstein, D. n., Tristani-Firouzi, M. n., Seidman, J. G., Seidman, C. E., Chung, W. K., Gelb, B. D., Sharp, A. J. 2020; 16 (11): e1009189

  Abstract

  Although DNA methylation is the best characterized epigenetic mark, the mechanism by which it is targeted to specific regions in the genome remains unclear. Recent studies have revealed that local DNA methylation profiles might be dictated by cis-regulatory DNA sequences that mainly operate via DNA-binding factors. Consistent with this finding, we have recently shown that disruption of CTCF-binding sites by rare single nucleotide variants (SNVs) can underlie cis-linked DNA methylation changes in patients with congenital anomalies. These data raise the hypothesis that rare genetic variation at transcription factor binding sites (TFBSs) might contribute to local DNA methylation patterning. In this work, by combining blood genome-wide DNA methylation profiles, whole genome sequencing-derived SNVs from 247 unrelated individuals along with 133 predicted TFBS motifs derived from ENCODE ChIP-Seq data, we observed an association between the disruption of binding sites for multiple TFs by rare SNVs and extreme DNA methylation values at both local and, to a lesser extent, distant CpGs. While the majority of these changes affected only single CpGs, 24% were associated with multiple outlier CpGs within ±1kb of the disrupted TFBS. Interestingly, disruption of functionally constrained sites within TF motifs lead to larger DNA methylation changes at nearby CpG sites. Altogether, these findings suggest that rare SNVs at TFBS negatively influence TF-DNA binding, which can lead to an altered local DNA methylation profile. Furthermore, subsequent integration of DNA methylation and RNA-Seq profiles from cardiac tissues enabled us to observe an association between rare SNV-directed DNA methylation and outlier expression of nearby genes. In conclusion, our findings not only provide insights into the effect of rare genetic variation at TFBS on shaping local DNA methylation and its consequences on genome regulation, but also provide a rationale to incorporate DNA methylation data to interpret the functional role of rare variants.

  View details for DOI 10.1371/journal.pgen.1009189

  View details for PubMedID 33216750

• EM-mosaic detects mosaic point mutations that contribute to congenital heart disease. Genome medicine Hsieh, A. n., Morton, S. U., Willcox, J. A., Gorham, J. M., Tai, A. C., Qi, H. n., DePalma, S. n., McKean, D. n., Griffin, E. n., Manheimer, K. B., Bernstein, D. n., Kim, R. W., Newburger, J. W., Porter, G. A., Srivastava, D. n., Tristani-Firouzi, M. n., Brueckner, M. n., Lifton, R. P., Goldmuntz, E. n., Gelb, B. D., Chung, W. K., Seidman, C. E., Seidman, J. G., Shen, Y. n. 2020; 12 (1): 42

  Abstract

  The contribution of somatic mosaicism, or genetic mutations arising after oocyte fertilization, to congenital heart disease (CHD) is not well understood. Further, the relationship between mosaicism in blood and cardiovascular tissue has not been determined.We developed a new computational method, EM-mosaic (Expectation-Maximization-based detection of mosaicism), to analyze mosaicism in exome sequences derived primarily from blood DNA of 2530 CHD proband-parent trios. To optimize this method, we measured mosaic detection power as a function of sequencing depth. In parallel, we analyzed our cohort using MosaicHunter, a Bayesian genotyping algorithm-based mosaic detection tool, and compared the two methods. The accuracy of these mosaic variant detection algorithms was assessed using an independent resequencing method. We then applied both methods to detect mosaicism in cardiac tissue-derived exome sequences of 66 participants for which matched blood and heart tissue was available.EM-mosaic detected 326 mosaic mutations in blood and/or cardiac tissue DNA. Of the 309 detected in blood DNA, 85/97 (88%) tested were independently confirmed, while 7/17 (41%) candidates of 17 detected in cardiac tissue were confirmed. MosaicHunter detected an additional 64 mosaics, of which 23/46 (50%) among 58 candidates from blood and 4/6 (67%) of 6 candidates from cardiac tissue confirmed. Twenty-five mosaic variants altered CHD-risk genes, affecting 1% of our cohort. Of these 25, 22/22 candidates tested were confirmed. Variants predicted as damaging had higher variant allele fraction than benign variants, suggesting a role in CHD. The estimated true frequency of mosaic variants above 10% mosaicism was 0.14/person in blood and 0.21/person in cardiac tissue. Analysis of 66 individuals with matched cardiac tissue available revealed both tissue-specific and shared mosaicism, with shared mosaics generally having higher allele fraction.We estimate that ~ 1% of CHD probands have a mosaic variant detectable in blood that could contribute to cardiac malformations, particularly those damaging variants with relatively higher allele fraction. Although blood is a readily available DNA source, cardiac tissues analyzed contributed ~ 5% of somatic mosaic variants identified, indicating the value of tissue mosaicism analyses.

  View details for DOI 10.1186/s13073-020-00738-1

  View details for PubMedID 32349777

• De novo and recessive forms of congenital heart disease have distinct genetic and phenotypic landscapes. Nature communications Watkins, W. S., Hernandez, E. J., Wesolowski, S., Bisgrove, B. W., Sunderland, R. T., Lin, E., Lemmon, G., Demarest, B. L., Miller, T. A., Bernstein, D., Brueckner, M., Chung, W. K., Gelb, B. D., Goldmuntz, E., Newburger, J. W., Seidman, C. E., Shen, Y., Yost, H. J., Yandell, M., Tristani-Firouzi, M. 2019; 10 (1): 4722

  Abstract

  The genetic architecture of sporadic congenital heart disease (CHD) is characterized by enrichment in damaging de novo variants in chromatin-modifying genes. To test the hypothesis that gene pathways contributing to de novo forms of CHD are distinct from those for recessive forms, we analyze 2391 whole-exome trios from the Pediatric Cardiac Genomics Consortium. We deploy a permutation-based gene-burden analysis to identify damaging recessive and compound heterozygous genotypes and disease genes, controlling for confounding effects, such as background mutation rate and ancestry. Cilia-related genes are significantly enriched for damaging rare recessive genotypes, but comparatively depleted for de novo variants. The opposite trend is observed for chromatin-modifying genes. Other cardiac developmental gene classes have less stratification by mode of inheritance than cilia and chromatin-modifying gene classes. Our analyses reveal dominant and recessive CHD are associated with distinct gene functions, with cilia-related genes providing a reservoir of rare segregating variation leading to CHD.

  View details for DOI 10.1038/s41467-019-12582-y

  View details for PubMedID 31624253

• Editorial introductions CURRENT OPINION IN PEDIATRICS Bernstein, D., Barth, B., Bernstein, H. H. 2019; 31 (5): V-VI

  View details for DOI 10.1097/MOP.0000000000000821

  View details for Web of Science ID 000507290000001

• Hypertrophic Cardiomyopathy Mutations With Opposite Effects on [latin sharp s]-myosin Biomechanics Show Similar Structural and Biomechanical Phenotypes in Human Induced Pluripotent Stem Cell Derived Cardiomyocytes (hipsc-cms) Schroer, A., Jung, G., Kooiker, K., Adhikari, A., Song Linda, Liu Chao, Ruppel, K., Wu Sean, Pruitt, B., Spudich, J., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2019

  View details for Web of Science ID 000511467800091

• Role of Telomere Dysfunction in Duchenne Muscular Dystrophy Cardiomyopathy Eguchi, A., Chang, A. C., Pardon, G., Pruitt, B. L., Bernstein, D., Blau, H. M. LIPPINCOTT WILLIAMS & WILKINS. 2019

  View details for Web of Science ID 000511467800276

• Gene-based genome-wide association studies and meta-analyses of conotruncal heart defects PLOS ONE Sewda, A., Agopian, A. J., Goldmuntz, E., Hakonarson, H., Morrow, B. E., Taylor, D., Mitchell, L. E., Kim, R., Srivastava, D., Bernstein, D., Brueckner, M., Lifton, R., Newburger, J., Roberts, A., Seidman, C., Seidman, J., Tennstedt, S., Dandreo, K., Miller, J., Romano-Adesman, A., Gelb, B., Chung, W., Porter, G., King, E. C., Goldmuntz, E., Tristani-Firouzi, M., Yost, H., Pediat Cardiac Genomics Consortium 2019; 14 (7): e0219926

  Abstract

  Conotruncal heart defects (CTDs) are among the most common and severe groups of congenital heart defects. Despite evidence of an inherited genetic contribution to CTDs, little is known about the specific genes that contribute to the development of CTDs. We performed gene-based genome-wide analyses using microarray-genotyped and imputed common and rare variants data from two large studies of CTDs in the United States. We performed two case-parent trio analyses (N = 640 and 317 trios), using an extension of the family-based multi-marker association test, and two case-control analyses (N = 482 and 406 patients and comparable numbers of controls), using a sequence kernel association test. We also undertook two meta-analyses to combine the results from the analyses that used the same approach (i.e. family-based or case-control). To our knowledge, these analyses are the first reported gene-based, genome-wide association studies of CTDs. Based on our findings, we propose eight CTD candidate genes (ARF5, EIF4E, KPNA1, MAP4K3, MBNL1, NCAPG, NDFUS1 and PSMG3). Four of these genes (ARF5, KPNA1, NDUFS1 and PSMG3) have not been previously associated with normal or abnormal heart development. In addition, our analyses provide additional evidence that genes involved in chromatin-modification and in ribonucleic acid splicing are associated with congenital heart defects.

  View details for DOI 10.1371/journal.pone.0219926

  View details for Web of Science ID 000482331900052

  View details for PubMedID 31314787

  View details for PubMedCentralID PMC6636758

• beta-Cardiac myosin hypertrophic cardiomyopathy mutations release sequestered heads and increase enzymatic activity. Nature communications Adhikari, A. S., Trivedi, D. V., Sarkar, S. S., Song, D., Kooiker, K. B., Bernstein, D., Spudich, J. A., Ruppel, K. M. 2019; 10 (1): 2685

  Abstract

  Hypertrophic cardiomyopathy (HCM) affects 1 in 500 people and leads to hyper-contractility of the heart. Nearly 40 percent of HCM-causing mutations are found in human beta-cardiac myosin. Previous studies looking at the effect of HCM mutations on the force, velocity and ATPase activity of the catalytic domain of human beta-cardiac myosin have not shown clear trends leading to hypercontractility at the molecular scale. Here we present functional data showing that four separate HCM mutations located at the myosin head-tail (R249Q, H251N) and head-head (D382Y, R719W) interfaces of a folded-back sequestered state referred to as the interacting heads motif (IHM) lead to a significant increase in the number of heads functionally accessible for interaction with actin. These results provide evidence that HCM mutations can modulate myosin activity by disrupting intramolecular interactions within the proposed sequestered state, which could lead to hypercontractility at the molecular level.

  View details for DOI 10.1038/s41467-019-10555-9

  View details for PubMedID 31213605

• Drp1/Fis1 interaction mediates mitochondrial dysfunction in septic cardiomyopathy JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY Haileselassie, B., Mukherjee, R., Joshi, A. U., Napier, B. A., Massis, L. M., Ostberg, N., Queliconi, B. B., Monack, D., Bernstein, D., Mochly-Rosen, D. 2019; 130: 160–69

  View details for DOI 10.1016/j.yjmcc.2019.04.006

  View details for Web of Science ID 000468257200016

• Compassionate deactivation of ventricular assist devices in children: A survey of pediatric ventricular assist device clinicians' perspectives and practices PEDIATRIC TRANSPLANTATION Kaufman, B. D., Hollander, S. A., Zhang, Y., Chen, S., Bernstein, D., Rosenthal, D. N., Almond, C. S., Murray, J. M., Burgart, A. M., Cohen, H. J., Kirkpatrick, J. N., Blume, E. D. 2019; 23 (3)

  View details for DOI 10.1111/petr.13359

  View details for Web of Science ID 000476931300005

• Substantial Cardiovascular Morbidity in Adults With Lower-Complexity Congenital Heart Disease CIRCULATION Saha, P., Potiny, P., Rigdon, J., Morello, M., Tcheandjieu, C., Romfh, A., Fernandes, S. M., McElhinney, D. B., Bernstein, D., Lui, G. K., Shaw, G. M., Ingelsson, E., Priest, J. R. 2019; 139 (16): 1889–99

  View details for DOI 10.1161/CIRCULATIONAHA.118.037064

  View details for Web of Science ID 000469321500006

• IMPAIRED BIOENERGETICS IN RIGHT VENTRICULAR FAILURE IS ASSOCIATED WITH LIPID PEROXIDATION AND DECREASED MITOCHONDRIAL DYNAMICS Hwang, H., Sandeep, N., Zhao, M., Hu, D., Lan, I., Coronado, M., Kooiker, K., Fajardo, G., Bernstein, D., Reddy, S. ELSEVIER SCIENCE INC. 2019: 648

  View details for Web of Science ID 000460565900648

• Substantial Cardiovascular Morbidity in Adults with Lower-Complexity Congenital Heart Disease. Circulation Saha, P., Potiny, P., Rigdon, J., Morello, M., Tcheandjieu, C., Romfh, A., Fernandes, S. M., McElhinney, D. B., Bernstein, D., Lui, G. K., Shaw, G. M., Ingelsson, E., Priest, J. R. 2019

  Abstract

  BACKGROUND: Although lower-complexity cardiac malformations constitute the majority of adult congenital heart disease (ACHD), the long-term risks of adverse cardiovascular events and relationship with conventional risk factors in this population are poorly understood. We aimed to quantify the risk of adverse cardiovascular events associated with lower-complexity ACHD that is unmeasured by conventional risk factors.METHODS: A multi-tiered classification algorithm was used to select individuals with lower-complexity ACHD and individuals without ACHD for comparison amongst >500,000 British adults in the UK Biobank (UKB). ACHD diagnoses were sub-classified as "isolated aortic valve (AoV)" and "non-complex" defects. Time-to-event analyses were conducted for primary endpoints of fatal or non-fatal acute coronary syndrome (ACS), ischemic stroke, heart failure (HF), and atrial fibrillation, and a secondary combined endpoint for major adverse cardiovascular event (MACE). Maximum follow-up time for the study period was 22 years using retrospectively and prospectively collected data from the UKB.RESULTS: We identified 2,006 individuals with lower-complexity ACHD and 497,983 unexposed individuals in the UKB (median [IQR] age at enrollment 58 [51,63]). Of the ACHD-exposed group, 59% were male; 51% were current or former smokers; 30% were obese; 69%, 41%, and 7% were diagnosed or treated for hypertension, hyperlipidemia, and diabetes respectively. After adjustment for 12 measured cardiovascular risk factors, ACHD remained strongly associated with the primary endpoints, with hazard ratios (HR) ranging from 2.0 (95% confidence interval [CI] 1.5-2.8, p<0.001) for ACS to 13.0 (95% CI 9.4-18.1, p<0.001) for HF. ACHD-exposed individuals with ≤2 cardiovascular risk factors had a 29% age-adjusted incidence rate of MACE in contrast to 13% in non-ACHD individuals with ≥5 risk factors.CONCLUSIONS: Individuals with lower-complexity ACHD had higher burden of adverse cardiovascular events relative to the general population that was unaccounted for by conventional cardiovascular risk factors. These findings highlight the need for closer surveillance of patients with mild to moderate ACHD and further investigation into management and mechanisms of cardiovascular risk unique to this growing population of high-risk adults.

  View details for PubMedID 30813762

• On the Functional Assessment of Hypertrophic Cardiomyopathy-Causing Mutations in Human beta-Cardiac Myosin and the Role of Myosin Binding Protein-C Trivedi, D. V., Sarkar, S. S., Adhikari, A. S., Morck, M. M., Kooiker, K. B., Bernstein, D., Ruppel, K. M., Spudich, J. A. CELL PRESS. 2019: 466A–467A

  View details for DOI 10.1016/j.bpj.2018.11.2520

  View details for Web of Science ID 000460779802344

• Compassionate deactivation of ventricular assist devices in children: A survey of pediatric ventricular assist device clinicians' perspectives and practices. Pediatric transplantation Kaufman, B. D., Hollander, S. A., Zhang, Y., Chen, S., Bernstein, D., Rosenthal, D. N., Almond, C. S., Murray, J. M., Burgart, A. M., Cohen, H. J., Kirkpatrick, J. N., Blume, E. D. 2019: e13359

  Abstract

  OBJECTIVES: This study's objective was to investigate compassionate ventricular assist device deactivation (VADdeact) in children from the perspective of the pediatric heart failure provider.BACKGROUND: Pediatric VAD use is a standard therapy for advanced heart failure. Serious adverse events may affect relative benefit of continued support, leading to consideration of VADdeact. Perspectives and practices regarding VADdeact have been studied in adults but not in children.METHODS: A web-based anonymous survey of clinicians for pediatric VAD patients (<18years) was sent to list-serves for the ISHLT Pediatric Council, the International Consortium of Circulatory Assist Clinicians Pediatric Taskforce, and the Pediatric Cardiac Intensivist Society.RESULTS: A total of 106 respondents met inclusion criteria of caring for pediatric VAD patients. Annual VAD volume per clinician ranged from <4 (33%) to >9 (20%). Seventy percent of respondents had performed VADdeact of a child. Response varied to VADdeact requests by parent or patient and was influenced by professional degree and region of practice. Except for the scenario of intractable suffering, no consensus on VADdeact appropriateness was reported. Age of child thought capable of making informed requests for VADdeact varied by subspecialty. The majority of respondents (62%) do not feel fully informed of relevant legal issues; 84% reported that professional society supported guidelines for VADdeact in children had utility.CONCLUSION: There is limited consensus regarding indications for VADdeact in children reported by pediatric VAD provider survey respondents. Knowledge gaps related to legal issues are evident; therefore, professional guidelines and educational resources related to pediatric VADdeact are needed.

  View details for PubMedID 30734422

• Drp1/Fis1 interaction mediates mitochondrial dysfunction in septic cardiomyopathy. Journal of molecular and cellular cardiology Haileselassie, B. n., Mukherjee, R. n., Joshi, A. U., Napier, B. A., Massis, L. M., Ostberg, N. P., Queliconi, B. B., Monack, D. n., Bernstein, D. n., Mochly-Rosen, D. n. 2019

  Abstract

  Mitochondrial dysfunction is a key contributor to septic cardiomyopathy. Although recent literature implicates dynamin related protein 1 (Drp1) and its mitochondrial adaptor fission 1 (Fis1) in the development of pathologic fission and mitochondrial failure in neurodegenerative disease, little is known about the role of Drp1/Fis1 interaction in the context of sepsis-induced cardiomyopathy. Our study tests the hypothesis that Drp1/Fis1 interaction is a major driver of sepsis-mediated pathologic fission, leading to mitochondrial dysfunction in the heart.H9C2 cardiomyocytes were treated with lipopolysaccharide (LPS) to evaluate changes in mitochondrial membrane potential, oxidative stress, cellular respiration, and mitochondrial morphology. Balb/c mice were treated with LPS, cardiac function was measured by echocardiogaphy, and mitochondrial morphology determined by electron microscopy (EM). Drp1/Fis1 interaction was inhibited by P110 to determine whether limiting mitochondrial fission can reduce LPS-induced oxidative stress and cardiac dysfunction.LPS-treated H9C2 cardiomyocytes demonstrated a decrease in mitochondrial respiration followed by an increase in mitochondrial oxidative stress and a reduction in membrane potential. Inhibition of Drp1/Fis1 interaction with P110 attenuated LPS-mediated cellular oxidative stress and preserved membrane potential. In vivo, cardiac dysfunction in LPS-treated mice was associated with increased mitochondrial fragmentation. Treatment with P110 reduced cardiac mitochondrial fragmentation, prevented decline in cardiac function, and reduced mortality.Sepsis decreases cardiac mitochondrial respiration and membrane potential while increasing oxidative stress and inducing pathologic fission. Treatment with P110 was protective in both in vitro and in vivo models of septic cardiomyopathy, suggesting a key role of Drp1/Fis1 interaction, and a potential target to reduce its morbidity and mortality.

  View details for PubMedID 30981733

• Pathologic gene network rewiring implicates PPP1R3A as a central regulator in pressure overload heart failure. Nature communications Cordero, P., Parikh, V. N., Chin, E. T., Erbilgin, A., Gloudemans, M. J., Shang, C., Huang, Y., Chang, A. C., Smith, K. S., Dewey, F., Zaleta, K., Morley, M., Brandimarto, J., Glazer, N., Waggott, D., Pavlovic, A., Zhao, M., Moravec, C. S., Tang, W. H., Skreen, J., Malloy, C., Hannenhalli, S., Li, H., Ritter, S., Li, M., Bernstein, D., Connolly, A., Hakonarson, H., Lusis, A. J., Margulies, K. B., Depaoli-Roach, A. A., Montgomery, S. B., Wheeler, M. T., Cappola, T., Ashley, E. A. 2019; 10 (1): 2760

  Abstract

  Heart failure is a leading cause of mortality, yet our understanding of the genetic interactions underlying this disease remains incomplete. Here, we harvest 1352 healthy and failing human hearts directly from transplant center operating rooms, and obtain genome-wide genotyping and gene expression measurements for a subset of 313. We build failing and non-failing cardiac regulatory gene networks, revealing important regulators and cardiac expression quantitative trait loci (eQTLs). PPP1R3A emerges as a regulator whose network connectivity changes significantly between health and disease. RNA sequencing after PPP1R3A knockdown validates network-based predictions, and highlights metabolic pathway regulation associated with increased cardiomyocyte size and perturbed respiratory metabolism. Mice lacking PPP1R3A are protected against pressure-overload heart failure. We present a global gene interaction map of the human heart failure transition, identify previously unreported cardiac eQTLs, and demonstrate the discovery potential of disease-specific networks through the description of PPP1R3A as a central regulator in heart failure.

  View details for DOI 10.1038/s41467-019-10591-5

  View details for PubMedID 31235787

• Stem cells: will they cure pediatric heart failure? Current opinion in pediatrics Bernstein, D. n. 2019

  Abstract

  The purpose of this review is to provide an overview of the state of cardiac regenerative medicine, including the unique opportunities and challenges in its application to pediatric patients.There has been a rapid proliferation of clinical studies using stem cells in adults with heart failure, yet little convincing evidence of clinically significant improvement. Readers will develop an understanding of the current limitations of stem cell treatments and the challenges to be overcome before they can achieve successful clinical translation.Clinical trials in cardiac regeneration using stem cells are advancing rapidly despite clear knowledge of mechanism and rigorous evidence in animal models. The potential for cardiac regeneration in children may be greater than in adults, given the smaller degree of scar present in nonischemic heart disease and the greater potential of the younger heart for repair. However, similar to adult trials, there has yet to be convincing evidence of a positive effect in pediatric patients, and rigorous controlled studies are still lacking. There is still much biology to be learned in cardiac regeneration; future clinical trials in children should be based on solid evidence in animal models of both efficacy and safety.

  View details for DOI 10.1097/MOP.0000000000000801

  View details for PubMedID 31335749

• Macrophage de novo NAD(+) synthesis specifies immune function in aging and inflammation NATURE IMMUNOLOGY Minhas, P. S., Liu, L., Moon, P. K., Joshi, A. U., Dove, C., Mhatre, S., Contrepois, K., Wang, Q., Lee, B. A., Coronado, M., Bernstein, D., Snyder, M. P., Migaud, M., Majeti, R., Mochly-Rosen, D., Rabinowitz, J. D., Andreasson, K. I. 2019; 20 (1): 50-+

  View details for DOI 10.1038/s41590-018-0255-3

  View details for Web of Science ID 000456273900014

• ROLE OF DRP1/FIS1-MEDIATED MITOCHONDRIAL FRAGMENTATION IN SEPSIS-INDUCED MYOCARDIAL DYSFUNCTION Haileselassie, B., Joshi, A., Mukherjee, R., Napier, B., Massis, L., Ostberg, N., Monack, D., Bernstein, D., Mochly-Rosen, D. LIPPINCOTT WILLIAMS & WILKINS. 2019

  View details for Web of Science ID 000498593400042

• Macrophage de novo NAD+ synthesis specifies immune function in aging and inflammation. Nature immunology Minhas, P. S., Liu, L., Moon, P. K., Joshi, A. U., Dove, C., Mhatre, S., Contrepois, K., Wang, Q., Lee, B. A., Coronado, M., Bernstein, D., Snyder, M. P., Migaud, M., Majeti, R., Mochly-Rosen, D., Rabinowitz, J. D., Andreasson, K. I. 2018

  Abstract

  Recent advances highlight a pivotal role for cellular metabolism in programming immune responses. Here, we demonstrate that cell-autonomous generation of nicotinamide adenine dinucleotide (NAD+) via the kynurenine pathway (KP) regulates macrophage immune function in aging and inflammation. Isotope tracer studies revealed that macrophage NAD+ derives substantially from KP metabolism of tryptophan. Genetic or pharmacological blockade of de novo NAD+ synthesis depleted NAD+, suppressed mitochondrial NAD+-dependent signaling and respiration, and impaired phagocytosis and resolution of inflammation. Innate immune challenge triggered upstream KP activation but paradoxically suppressed cell-autonomous NAD+ synthesis by limiting the conversion of downstream quinolinate to NAD+, a profile recapitulated in aging macrophages. Increasing de novo NAD+ generation in immune-challenged or aged macrophages restored oxidative phosphorylation and homeostatic immune responses. Thus, KP-derived NAD+ operates as a metabolic switch to specify macrophage effector responses. Breakdown of de novo NAD+ synthesis may underlie declining NAD+ levels and rising innate immune dysfunction in aging and age-associated diseases.

  View details for PubMedID 30478397

• Aortic valve phenotype associated with filamin-A mutations: a comprehensive echocardiographic and outcomes analyses Capoulade, R., Cueff, C., Piriou, N., Toquet, C., Blandin, S., Guimbretiere, G., Omen, T., Aalberts, J., Bernstein, D., Bernstein, J., Trochu, J. N., Le Marec, H., Merot, J., Schott, J. J., Le Tourneau, T. OXFORD UNIV PRESS. 2018: 1123

  View details for Web of Science ID 000459824003532

• Advances in pediatric cardiology 2018. Current opinion in pediatrics Bernstein, D. 2018

  View details for PubMedID 29979238

• Prospective Analysis of EBV plus PTLD in a Multi-Center Study of Pediatric Transplant Recipients Martinez, O. M., Krams, S. M., Lapasaran, M., Boyd, S. D., Bernstein, D., Twist, C., Weinberg, K., Gratzinger, D., Tan, B., Armstrong, B., Ikle, D., Brown, M., Robien, M., Esquivel, C. O. LIPPINCOTT WILLIAMS & WILKINS. 2018: S319

  View details for Web of Science ID 000444541200511

• Post-transplant outcomes in pediatric ventricular assist device patients: A PediMACS-Pediatric Heart Transplant Study linkage analysis JOURNAL OF HEART AND LUNG TRANSPLANTATION Sutcliffe, D. L., Pruitt, E., Cantor, R. S., Godown, J., Lane, J., Turrentine, M. W., Law, S. P., Lantz, J. L., Kirklin, J. K., Bernstein, D., Blume, E. D. 2018; 37 (6): 715–22

  Abstract

  Pediatric ventricular assist device (VAD) support as bridge to transplant has improved waitlist survival, but the effects of pre-implant status and VAD-related events on post-transplant outcomes have not been assessed. This study is a linkage analysis between the PediMACS and Pediatric Heart Transplant Study databases to determine the effects of VAD course on post-transplant outcomes.Database linkage between October 1, 2012 and December 31, 2015 identified 147 transplanted VAD patients, the primary study group. The comparison cohort was composed of 630 PHTS patients without pre-transplant VAD support. The primary outcome was post-transplant survival, with secondary outcomes of post-transplant length of stay, freedom from infection and freedom from rejection.At implant, the VAD cohort was INTERMACS Profile 1 in 33 (23%), Profile 2 in 89 (63%) and Profile 3 in 14 (10%) patients. The VAD cohort was older, larger, and less likely to have congenital heart disease (p < 0.0001). However, they had greater requirements for inotrope and ventilator support and increased liver and renal dysfunction (p < 0.0001), both of which normalized at transplant after device support. Importantly, there were no differences in 1-year post-transplant survival (96% vs 93%, p = 0.3), freedom from infection (81% vs 79%, p = 0.9) or freedom from rejection (71% vs 74%, p = 0.87) between cohorts.Pediatric VAD patients have post-transplant outcomes equal to that of medically supported patients, despite greater pre-implant illness severity. Post-transplant survival, hospital length of stay, infection and rejection were not affected by patient acuity at VAD implantation or VAD-related complications. Therefore, VAD as bridge to transplant mitigates severity of illness in children.

  View details for PubMedID 29373179

• Prospective Analysis of EBV plus PTLD Incidence in Pediatric Transplant Recipients in the Modern Era. Martinez, O., Krams, S., Lapasaran, M., Boyd, S., Bernstein, D., Twist, C., Weinberg, K., Gratzinger, D., Tan, B., Armstrong, B., Ikle, D., Brown, M., Robien, M., Esquivel, C., CTOTC-06 Investigators WILEY. 2018: 352–53

  View details for Web of Science ID 000431965401270

• Apelin and APJ orchestrate complex tissue-specific control of cardiomyocyte hypertrophy and contractility in the hypertrophy-heart failure transition. American journal of physiology. Heart and circulatory physiology Parikh, V. N., Liu, J., Shang, C., Woods, C., Chang, A. C., Zhao, M., Charo, D. N., Grunwald, Z., Huang, Y., Seo, K., Tsao, P. S., Bernstein, D., Ruiz-Lozano, P., Quertermous, T., Ashley, E. A. 2018

  Abstract

  The G protein coupled receptor APJ is a promising therapeutic target for heart failure. Constitutive deletion of APJ in the mouse is protective against the hypertrophy-heart failure transition via elimination of ligand-independent, beta-arrestin dependent stretch transduction. However, the cellular origin of this stretch transduction and the details of its interaction with apelin signaling remain unknown. We generated mice with conditional elimination of APJ in the endothelium (APJendo-/-) and myocardium (APJmyo-/-). No baseline difference was observed in LV function in APJendo-/-, APJmyo-/- or controls (APJendo+/+, APJmyo+/+). After exposure to transaortic constriction (TAC), APJendo-/- animals developed left ventricular failure while APJmyo-/- were protected. At the cellular level, carbon fiber stretch of freshly isolated single cardiomyocytes demonstrated decreased contractile response to stretch in APJ-/- cardiomyocytes compared to APJ+/+ cardiomyocytes. Calcium transient did not change with stretch in either APJ-/- or APJ+/+ cardiomyocytes. Application of apelin to APJ+/+ cardiomyocytes resulted in decreased calcium transient. Further, hearts of mice treated with apelin exhibited decreased phosphorylation at Troponin I (cTnI) N-terminal residues (Ser 22,23), consistent with increased calcium sensitivity. These data establish that APJ stretch transduction is mediated specifically by myocardial APJ, that APJ is necessary for stretch-induced increases in contractility, and that apelin opposes APJ's stretch-mediated hypertrophy signaling by lowering calcium transient while maintaining contractility through myofilament calcium sensitization. These findings underscore apelin's unique potential as a therapeutic agent that can simultaneously support cardiac function and protect against the hypertrophy-heart failure transition.

  View details for PubMedID 29775410

• Renin-Angiotensin-Aldosterone System Inhibitors for Right Ventricular Dysfunction in Tetralogy of Fallot Quo Vadis? CIRCULATION Reddy, S., Bernstein, D., Newburger, J. W. 2018; 137 (14): 1472–74

  View details for PubMedID 29610128

  View details for PubMedCentralID PMC5886745

• Functional Assays to Screen and Dissect Genomic Hits: Doubling Down on the National Investment in Genomic Research. Circulation. Genomic and precision medicine Musunuru, K., Bernstein, D., Cole, F. S., Khokha, M. K., Lee, F. S., Lin, S., McDonald, T. V., Moskowitz, I. P., Quertermous, T., Sankaran, V. G., Schwartz, D. A., Silverman, E. K., Zhou, X., Hasan, A. A., Luo, X. J. 2018; 11 (4): e002178

  Abstract

  The National Institutes of Health have made substantial investments in genomic studies and technologies to identify DNA sequence variants associated with human disease phenotypes. The National Heart, Lung, and Blood Institute has been at the forefront of these commitments to ascertain genetic variation associated with heart, lung, blood, and sleep diseases and related clinical traits. Genome-wide association studies, exome- and genome-sequencing studies, and exome-genotyping studies of the National Heart, Lung, and Blood Institute-funded epidemiological and clinical case-control studies are identifying large numbers of genetic variants associated with heart, lung, blood, and sleep phenotypes. However, investigators face challenges in identification of genomic variants that are functionally disruptive among the myriad of computationally implicated variants. Studies to define mechanisms of genetic disruption encoded by computationally identified genomic variants require reproducible, adaptable, and inexpensive methods to screen candidate variant and gene function. High-throughput strategies will permit a tiered variant discovery and genetic mechanism approach that begins with rapid functional screening of a large number of computationally implicated variants and genes for discovery of those that merit mechanistic investigation. As such, improved variant-to-gene and gene-to-function screens-and adequate support for such studies-are critical to accelerating the translation of genomic findings. In this White Paper, we outline the variety of novel technologies, assays, and model systems that are making such screens faster, cheaper, and more accurate, referencing published work and ongoing work supported by the National Heart, Lung, and Blood Institute's R21/R33 Functional Assays to Screen Genomic Hits program. We discuss priorities that can accelerate the impressive but incomplete progress represented by big data genomic research.

  View details for PubMedID 29654098

• Response by Bernstein to Letter Regarding Article, "Anthracycline Cardiotoxicity: Worrisome Enough to Have You Quaking?" CIRCULATION RESEARCH Bernstein, D. 2018; 122 (7): E64–E65

  View details for PubMedID 29599280

• CONGENITAL HEART DISEASE CONFERS SUBSTANTIAL RISK OF ACQUIRED CARDIOVASCULAR DISEASE AMONGST BRITISH ADULTS Saha, P., Potiny, P., Tcheandjieu, C., Fernandes, S. M., Romfh, A., Bernstein, D., Lui, G. K., Ingelsson, E., Priest, J. ELSEVIER SCIENCE INC. 2018: 553

  View details for DOI 10.1016/S0735-1097(18)31094-5

  View details for Web of Science ID 000429659701403

• Mechanobiology of Myosin Mutations and Myofibril Remodeling in iPSC-Cardiomyocytes Schroer, A., Kooiker, K., Adhikari, A., Ruppel, K., Bernstein, D., Spudich, J., Pruitt, B. CELL PRESS. 2018: 496A–497A

  View details for Web of Science ID 000430563200233

• Anthracycline Cardiotoxicity Worrisome Enough to Have You Quaking? CIRCULATION RESEARCH Bernstein, D. 2018; 122 (2): 188–90

  View details for PubMedID 29348242

  View details for PubMedCentralID PMC5776743

• Dynamics of Viral and Host Immune Cell MicroRNA Expression during Acute Infectious Mononucleosis FRONTIERS IN MICROBIOLOGY Kaul, V., Weinberg, K. I., Boyd, S. D., Bernstein, D., Esquivel, C. O., Martinez, O. M., Krams, S. M. 2018; 8

  View details for DOI 10.3389/fmicb.2017.02666

  View details for Web of Science ID 000419879800001

• Physiological Mitochondrial Fragmentation Is a Normal Cardiac Adaptation to Increased Energy Demand. Circulation research Coronado, M. n., Fajardo, G. n., Nguyen, K. n., Zhao, M. n., Kooiker, K. n., Jung, G. n., Hu, D. Q., Reddy, S. n., Sandoval, E. n., Stotland, A. n., Gottlieb, R. A., Bernstein, D. n. 2018; 122 (2): 282–95

  Abstract

  Mitochondria play a dual role in the heart, responsible for meeting energetic demands and regulating cell death. Paradigms have held that mitochondrial fission and fragmentation are the result of pathological stresses, such as ischemia, are an indicator of poor mitochondrial health, and lead to mitophagy and cell death. However, recent studies demonstrate that inhibiting fission also results in decreased mitochondrial function and cardiac impairment, suggesting that fission is important for maintaining cardiac and mitochondrial bioenergetic homeostasis.The purpose of this study is to determine whether mitochondrial fission and fragmentation can be an adaptive mechanism used by the heart to augment mitochondrial and cardiac function during a normal physiological stress, such as exercise.We demonstrate a novel role for cardiac mitochondrial fission as a normal adaptation to increased energetic demand. During submaximal exercise, physiological mitochondrial fragmentation results in enhanced, rather than impaired, mitochondrial function and is mediated, in part, by β1-adrenergic receptor signaling. Similar to pathological fragmentation, physiological fragmentation is induced by activation of dynamin-related protein 1; however, unlike pathological fragmentation, membrane potential is maintained and regulators of mitophagy are downregulated. Inhibition of fission with P110, Mdivi-1 (mitochondrial division inhibitor), or in mice with cardiac-specific dynamin-related protein 1 ablation significantly decreases exercise capacity.These findings demonstrate the requirement for physiological mitochondrial fragmentation to meet the energetic demands of exercise, as well as providing additional support for the evolving conceptual framework, where mitochondrial fission and fragmentation play a role in the balance between mitochondrial maintenance of normal physiology and response to disease.

  View details for PubMedID 29233845

  View details for PubMedCentralID PMC5775047

• EVALUATION OF THE TEMPORAL CHANGES IN CARDIAC BIOENERGETICS IN THE SETTING OF SEPSIS Haileselassie, B., Joshi, A., Bernstein, D., Mochly-Rosen, D. LIPPINCOTT WILLIAMS & WILKINS. 2018: 742

  View details for DOI 10.1097/01.ccm.0000529519.11903.9b

  View details for Web of Science ID 000436796200681

• Human Induced Pluripotent Stem Cell (hiPSC)-Derived Cells to Assess Drug Cardiotoxicity: Opportunities and Problems. Annual review of pharmacology and toxicology Magdy, T. n., Schuldt, A. J., Wu, J. C., Bernstein, D. n., Burridge, P. W. 2018; 58: 83–103

  Abstract

  Billions of US dollars are invested every year by the pharmaceutical industry in drug development, with the aim of introducing new drugs that are effective and have minimal side effects. Thirty percent of in-pipeline drugs are excluded in an early phase of preclinical and clinical screening owing to cardiovascular safety concerns, and several lead molecules that pass the early safety screening make it to market but are later withdrawn owing to severe cardiac side effects. Although the current drug safety screening methodologies can identify some cardiotoxic drug candidates, they cannot accurately represent the human heart in many aspects, including genomics, transcriptomics, and patient- or population-specific cardiotoxicity. Despite some limitations, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a powerful and evolving technology that has been shown to recapitulate many attributes of human cardiomyocytes and their drug responses. In this review, we discuss the potential impact of the inclusion of the hiPSC-CM platform in premarket candidate drug screening.

  View details for PubMedID 28992430

• Advances in paediatric cardiology 2017: the genetics of paediatric cardiovascular disease CURRENT OPINION IN PEDIATRICS Bernstein, D. 2017; 29 (5): 511–12

  View details for PubMedID 28700418

• Induced Pluripotent Stem Cell-Derived Cardiomyocytes: A Platform for Testing For Drug Cardiotoxicity. Progress in pediatric cardiology Bernstein, D. 2017; 46: 2-6

  Abstract

  Off-target cardiotoxicity has been a significant impediment to the development of new drugs. Traditional platforms for screening for cardiotoxicity are both overly sensitive and limited in their ability to predict cardiotoxicity that is often only uncovered after years of clinical use. A major impediment has been the lack of a human cardiomyocyte cell line. The recent discovery that adult somatic human cells (white blood cells or skin fibroblasts) can be reprogrammed into pluripotent stem cells (hiPSCs) and then differentiated into beating cardiomyocytes (hiPSC-CMs) provides an exciting new platform for drug cardiotoxicity and efficacy testing. One major advantage of using patient-derived hiPSC-CMs for drug testing is their ability to recapitulate population genetic variations (single nucleotide polymorphisms) that influence drug toxicity, providing a powerful new tool in the field of pharmacogenomics and personalized medicine.

  View details for DOI 10.1016/j.ppedcard.2017.07.001

  View details for PubMedID 29200805

  View details for PubMedCentralID PMC5708578

• Induced pluripotent stem cell-derived cardiomyocytes: A platform for testing for drug cardiotoxicity PROGRESS IN PEDIATRIC CARDIOLOGY Bernstein, D. 2017; 46: 2–6

  View details for DOI 10.1016/j.ppedcard.2017.07.001

  View details for Web of Science ID 000426221300002

• miR-21 is associated with fibrosis and right ventricular failure. JCI insight Reddy, S., Hu, D., Zhao, M., Blay, E., Sandeep, N., Ong, S., Jung, G., Kooiker, K. B., Coronado, M., Fajardo, G., Bernstein, D. 2017; 2 (9)

  Abstract

  Combined pulmonary insufficiency (PI) and stenosis (PS) is a common long-term sequela after repair of many forms of congenital heart disease, causing progressive right ventricular (RV) dilation and failure. Little is known of the mechanisms underlying this combination of preload and afterload stressors. We developed a murine model of PI and PS (PI+PS) to identify clinically relevant pathways and biomarkers of disease progression. Diastolic dysfunction was induced (restrictive RV filling, elevated RV end-diastolic pressures) at 1 month after generation of PI+PS and progressed to systolic dysfunction (decreased RV shortening) by 3 months. RV fibrosis progressed from 1 month (4.4% ± 0.4%) to 3 months (9.2% ± 1%), along with TGF-β signaling and tissue expression of profibrotic miR-21. Although plasma miR-21 was upregulated with diastolic dysfunction, it was downregulated with the onset of systolic dysfunction), correlating with RV fibrosis. Plasma miR-21 in children with PI+PS followed a similar pattern. A model of combined RV volume and pressure overload recapitulates the evolution of RV failure unique to patients with prior RV outflow tract surgery. This progression was characterized by enhanced TGF-β and miR-21 signaling. miR-21 may serve as a plasma biomarker of RV failure, with decreased expression heralding the need for valve replacement.

  View details for DOI 10.1172/jci.insight.91625

  View details for PubMedID 28469078

• Pharmacogenomic screening for anthracycline-induced cardiotoxicity in childhood cancer BRITISH JOURNAL OF CLINICAL PHARMACOLOGY Aminkeng, F., Ross, C. D., Rassekh, S. R., Rieder, M. J., Bhavsar, A. P., Sanatani, S., Bernstein, D., Hayden, M. R., Amstutz, U., Carleton, B. C. 2017; 83 (5): 1143–45

  View details for PubMedID 28317142

  View details for PubMedCentralID PMC5401971

• Cancer recurrence and mortality after pediatric heart transplantation for anthracycline cardiomyopathy: A report from the Pediatric Heart Transplant Study (PHTS) group. Pediatric transplantation Bock, M. J., Pahl, E., Rusconi, P. G., Boyle, G. J., Parent, J. J., Twist, C. J., Kirklin, J. K., Pruitt, E., Bernstein, D. 2017

  Abstract

  We aimed to determine whether malignancy after pediatric HTx for ACM affects overall post-HTx survival. Patients <18y listed for HTx for ACM in the PHTS database between 1993 and 2014 were compared to those with DCM. A 2:1 matched DCM cohort was also compared. Wait-list and post-HTx survival, along with freedom from common HTx complications, were compared. Eighty subjects were listed due to ACM, whereas 1985 were listed for DCM. Although wait-list survival was higher in the ACM group, post-HTx survival was lower for the ACM cohort. Neither difference persisted in the matched cohort analysis. Primary cause of death in the ACM group was infection, which was higher than the DCM group. Malignancy rates were not different. All ACM malignancies were due to PTLD without primary cancer recurrence or SMN. Long-term graft survival after pediatric HTx for ACM is no different than for matched DCM peers, nor is there an increased risk of any malignancy. However, risk of infection and death from infection after HTx are higher in the ACM group. Further studies are needed to assess the effects of prior chemotherapy on susceptibility to infection in this group.

  View details for DOI 10.1111/petr.12923

  View details for PubMedID 28378408

• Outcomes of US Patients with Marfans Syndrome Listed for Heart Transplantation Kaufman, B. D., Tierney, S. E., Bernstein, D., Chen, S. H., Dykes, J., Hollander, S. A., Liang, D. H., Maeda, K., Priest, J., Reinhartz, O., Rosenthal, D. N., Almond, C. ELSEVIER SCIENCE INC. 2017: S393–S394

  View details for Web of Science ID 000398839801324

• Hemodynamics of the Pediatric Failing Fontan Dykes, J. C., McElhinney, D. B., Bernstein, D., Chrisant, M. R., Chen, S., Daly, K., Ameduri, R. K., Knecht, K. R., Richmond, M. E., Lin, K. Y., Urschel, S., Simmonds, J., Simpson, K. E., Almond, C. S., Chen, S. ELSEVIER SCIENCE INC. 2017: S22

  View details for Web of Science ID 000398839800036

• The miRNome of EBV plus PTLD is Distinct from EBV plus Infectious Mononucleosis Balachandran, Y., Kaul, V., Maloney, E., Harris-Arnold, A., Weinberg, K., Boyd, S., Bernstein, D., Esquivel, C., Martinez, O., Krams, S. WILEY. 2017: 402

  View details for Web of Science ID 000404515702552

• Avoidance of a C1q Positive Crossmatch Prevents Both Early and Late Antibody-Mediated Rejection in Pediatric Heart Transplant Recipients Hollander, S. A., Peng, D. M., Mills, M., Berry, G. J., Pedrigo, M., Chen, S., Tyan, D. B., Bernstein, D., Rosenthal, D. N. ELSEVIER SCIENCE INC. 2017: S268

  View details for Web of Science ID 000398839800697

• Post-Transplant Outcomes in Pediatric VAD Patients: A Pedimacs-PHTS Linkage Study Sutcliffe, D. L., Pruitt, E., Cantor, R. S., Godown, J., Lane, J., Turrentine, M. W., Law, S. P., Lantz, J. L., Naftel, D. C., Kirklin, J. K., Bernstein, D., Blume, E. D. ELSEVIER SCIENCE INC. 2017: S36

  View details for Web of Science ID 000398839800072

• Compassionate Deactivation of Ventricular Assist Devices in Children: A Survey of Pediatric VAD Clinicians' Perspectives and Practices Kaufman, B. D., Hollander, S. A., Chen, S. H., Bernstein, D., Rosenthal, D. N., Almond, C., Murray, J. M., Burgart, A. M., Cohen, H. J., Kirkpatrick, J. N., Blume, E. D. ELSEVIER SCIENCE INC. 2017: S37–S38

  View details for Web of Science ID 000398839800075

• Impact of Heart Transplantation on the Functional Status of US Children With End-Stage Heart Failure. Circulation Peng, D. M., Zhang, Y., Rosenthal, D. N., Palmon, M., Chen, S., Kaufman, B. D., Maeda, K., Hollander, S. A., McDonald, N., Smoot, L. B., Bernstein, D., Almond, C. S. 2017; 135 (10): 939-950

  Abstract

  There are limited data describing the functional status (FS) of children after heart transplant (HT). We sought to describe the FS of children surviving at least 1 year after HT, to evaluate the impact of HT on FS, and to identify factors associated with abnormal FS post-HT.Organ Procurement and Transplantation Network data were used to identify all US children <21 years of age surviving ≥1 year post-HT from 2005 to 2014 with a functional status score (FSS) available at 3 time points (listing, transplant, ≥1 year post-HT). Logistic regression and generalized estimating equations were used to identify factors associated with abnormal FS (FSS≤8) post-HT.A total of 1633 children met study criteria. At the 1-year assessment, 64% were "fully active/no limitations" (FSS=10), 21% had "minor limitations with strenuous activity" (FSS=9); and 15% scored ≤8. In comparison with listing FS, FS at 1 year post-HT increased in 91% and declined/remained unchanged in 9%. A stepwise regression procedure selected the following variables for association with abnormal FS at 1 year post-HT: ≥18 years of age (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.2-2.7), black race (OR, 1.5; 95% CI, 1.1-2.0), support with ≥inotropes at HT (OR, 1.7; 95% CI, 1.2-2.5), hospitalization status at HT (OR, 1.5; 95% CI, 1.0-2.19), chronic steroid use at HT (OR, 1.5; 95% CI, 1.0-2.2), and treatment for early rejection (OR, 2.0; 95% CI, 1.5-2.7).Among US children who survive at least 1 year after HT, FS is excellent for the majority of patients. HT is associated with substantial improvement in FS for most children. Early rejection, older age, black race, chronic steroid use, hemodynamic support at HT, and being hospitalized at HT are associated with abnormal FS post-HT.

  View details for DOI 10.1161/CIRCULATIONAHA.115.016520

  View details for PubMedID 28119383

• Rehospitalization after pediatric heart transplantation: Incidence, indications, and outcomes. Pediatric transplantation Hollander, S. A., McElhinney, D. B., Almond, C. S., McDonald, N., Chen, S., Kaufman, B. D., Bernstein, D., Rosenthal, D. N. 2017; 21 (1)

  Abstract

  We report the patterns of rehospitalization after pediatric heart transplant (Htx) at a single center. Retrospective review of 107 consecutive pediatric Htx recipients between January 22, 2007, and August 28, 2014, who survived their initial transplant hospitalization. The frequency, duration, and indications for all hospitalizations between transplant hospitalization discharge and September 30, 2015, were analyzed. A total of 444 hospitalization episodes occurred in 90 of 107 (84%) patients. The median time to first rehospitalization was 59.5 (range 1-1526) days, and the median length of stay was 2.5 (range 0-81) days. There were an average of two hospitalizations per patient in the first year following transplant hospitalization, declining to about 0.8 per patient per year starting at 3 years post-transplant. Admissions for viral infections were most common, occurring in 93 of 386 (24%), followed by rule out sepsis in 61 of 386 (16%). Admissions for suspected or confirmed rejection were less frequent, accounting for 41 of 386 (11%) and 31 of 386 (8%) of all admissions, respectively. Survival to discharge after rehospitalization was 97%. Hospitalization is common after pediatric Htx, particularly in the first post-transplant year, with the most frequent indications for hospitalization being viral illness and rule out sepsis. After the first post-transplant year, the risk for readmission falls significantly but remains constant for several years.

  View details for DOI 10.1111/petr.12857

  View details for PubMedID 27891727

• The End of Life Experience of Pediatric Heart Transplant Recipients. Journal of pain and symptom management Hollander, S. A., Dykes, J., Chen, S., Barkoff, L., Sourkes, B., Cohen, H., Rosenthal, D. N., Bernstein, D., Kaufman, B. D. 2017

  Abstract

  Despite advances in therapies, many pediatric heart transplant (Htx) recipients will die prematurely. We characterized the circumstances surrounding death in this cohort, including location of death and interventions performed in the final 24 hours.We reviewed all patients who underwent Htx at Lucile Packard Children's Hospital, Stanford, survived hospital discharge, and subsequently died between July 19, 2007 and September 13, 2015. The primary outcome studied was location of death, characterized as inpatient, outpatient, or emergency department. Circumstances of death (withdrawal of life-sustaining treatment, death during resuscitation, or death without resuscitation with/without do not resuscitate) and interventions performed in the last 24 hours of life were also analyzed.Twenty-three patients met the entry criteria. The median age at death was 12 (range 2-20) years, and the median time between transplant and death was 2.8 (range 0.8-11) years. Four (17%) died at home, and three (13%) died in the emergency department. Sixteen (70%) patients died in the hospital, 14 of 16 (88%) of whom died in an intensive care unit. Five of 23 (22%) patients experienced attempted resuscitation. Interventions performed in the last 24 hours of life included intubation (74%), mechanical support (30%), and dialysis (22%). Most patients had a recent outpatient clinical encounter with normal graft function within 60 days of dying.Death in children after Htx often occurs in the inpatient setting, particularly the intensive care unit. Medical interventions, including attempted resuscitation, are common at the end of life. Given the difficulty in anticipating life-threatening events, earlier discussions with patients regarding end-of-life wishes are appropriate, even in those with normal graft function.

  View details for DOI 10.1016/j.jpainsymman.2016.12.334

  View details for PubMedID 28063864

• Impact of the 18th birthday on waitlist outcomes among young adults listed for heart transplant: A regression discontinuity analysis. The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation Peng, D. M., Qu, Q. n., McDonald, N. n., Hollander, S. A., Bernstein, D. n., Maeda, K. n., Kaufman, B. D., Rosenthal, D. N., McElhinney, D. B., Almond, C. S. 2017; 36 (11): 1185–91

  Abstract

  Patients listed for heart transplant after their 18th birthday purportedly wait longer to receive a donor heart compared with patients listed before their 18th birthday. It is unclear whether there is an actual difference in wait times and whether any difference in wait time is associated with lower likelihood of transplant and/or higher risk of mortality.Organ procurement and transplant network data were used to identify all patients listed for heart transplant between 2006 and 2014 within a 1-year period before and after their 18th birthday. The primary study end-point was the waiting time to receive a donor heart. Secondary end-points included the probability of transplant and waitlist mortality. Regression discontinuity analysis was used to analyze the effect of age on either side of the sharp cut-off value of age 18 years (6,574 days of life), when allocation of donor hearts transitions from the pediatric to adult allocation system.A total of 360 patients met the study inclusion criteria, including 207 (57.5%) listed during the 12-month period before their 18th birthday under the pediatric allocation system, and 153 (42.5%) listed during the 12 months after their 18th birthday under the adult allocation system. The pediatric cohort was more likely to be listed Status 1A. Otherwise, the 2 groups shared similar baseline characteristics. Overall, patients listed after their 18th birthday waited 8.5 months longer to receive a transplant than adolescents listed before their 18th birthday (p = 0.01) and had a 47% lower probability of receiving a transplant (p = 0.001), but there was no difference in waitlist mortality (p = 0.37).Patients listed for heart transplant shortly after their 18th birthday have significantly longer wait-times compared with patients listed shortly before their 18th birthday and a lower probability of transplant, but no significant difference in waitlist mortality. For medically fragile adolescents at high risk of death, birth date may be a relevant factor in the timing of heart transplant listing.

  View details for PubMedID 28712678

• Reduced Bmpr2 Signaling Impairs Right Ventricular Heart Function And Exaggerates Cardiac Fibrosis Upon Chronic Pressure Overload Boehm, M., Tian, X., Zhao, M., Dannewitz, S., Kuramoto, K., Kuang, J., Reddy, S., Bernstein, D., Ashley, E., Spiekerkoetter, E. AMER THORACIC SOC. 2017

  View details for Web of Science ID 000400372504750

• Passive Stretch Induces Structural and Functional Maturation of Engineered Heart Muscle as Predicted by Computational Modeling. Stem cells (Dayton, Ohio) Abilez, O. J., Tzatzalos, E. n., Yang, H. n., Zhao, M. T., Jung, G. n., Zöllner, A. M., Tiburcy, M. n., Riegler, J. n., Matsa, E. n., Shukla, P. n., Zhuge, Y. n., Chour, T. n., Chen, V. C., Burridge, P. W., Karakikes, I. n., Kuhl, E. n., Bernstein, D. n., Couture, L. A., Gold, J. D., Zimmermann, W. H., Wu, J. C. 2017

  Abstract

  The ability to differentiate human pluripotent stem cells (hPSCs) into cardiomyocytes (CMs) makes them an attractive source for repairing injured myocardium, disease modeling, and drug testing. Although current differentiation protocols yield hPSC-CMs to >90% efficiency, hPSC-CMs exhibit immature characteristics. With the goal of overcoming this limitation, we tested the effects of varying passive stretch on engineered heart muscle (EHM) structural and functional maturation, guided by computational modeling.Human embryonic stem cells (hESCs, H7 line) or human induced pluripotent stem cells (hiPSCs, IMR-90 line) were differentiated to human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) in vitro using a small molecule based protocol. hPSC-CMs were characterized by troponin(+) flow cytometry as well as electrophysiological measurements. Afterwards, 1.2 x 10(6) hPSC-CMs were mixed with 0.4 x 10(6) human fibroblasts (IMR-90 line) (3:1 ratio) and Type-I collagen. The blend was cast into custom-made 12-mm long polydimethylsiloxane (PDMS) reservoirs to vary nominal passive stretch of EHMs to 5, 7, or 9 mm. EHM characteristics were monitored for up to 50 days, with EHMs having a passive stretch of 7 mm giving the most consistent formation. Based on our initial macroscopic observations of EHM formation, we created a computational model that predicts the stress distribution throughout EHMs, which is a function of cellular composition, cellular ratio, and geometry. Based on this predictive modeling, we show cell alignment by immunohistochemistry and coordinated calcium waves by calcium imaging. Furthermore, coordinated calcium waves and mechanical contractions were apparent throughout entire EHMs. The stiffness and active forces of hPSC-derived EHMs are comparable to rat neonatal cardiomyocyte-derived EHMs. Three-dimensional EHMs display increased expression of mature cardiomyocyte genes including sarcomeric protein troponin-T, calcium and potassium ion channels, β-adrenergic receptors, and t-tubule protein caveolin-3.Passive stretch affects the structural and functional maturation of EHMs. Based on our predictive computational modeling, we show how to optimize cell alignment and calcium dynamics within EHMs. These findings provide a basis for the rational design of EHMs, which enables future scale-up productions for clinical use in cardiovascular tissue engineering. This article is protected by copyright. All rights reserved.

  View details for PubMedID 29086457

• Angiotensin-Converting Enzyme Inhibition Early After Heart Transplantation. Journal of the American College of Cardiology Fearon, W. F., Okada, K. n., Kobashigawa, J. A., Kobayashi, Y. n., Luikart, H. n., Sana, S. n., Daun, T. n., Chmura, S. A., Sinha, S. n., Cohen, G. n., Honda, Y. n., Pham, M. n., Lewis, D. B., Bernstein, D. n., Yeung, A. C., Valantine, H. A., Khush, K. n. 2017; 69 (23): 2832–41

  Abstract

  Cardiac allograft vasculopathy (CAV) remains a leading cause of mortality after heart transplantation (HT). Angiotensin-converting enzyme inhibitors (ACEIs) may retard the development of CAV but have not been well studied after HT.This study tested the safety and efficacy of the ACEI ramipril on the development of CAV early after HT.In this prospective, multicenter, randomized, double-blind, placebo-controlled trial, 96 HT recipients were randomized to undergo ramipril or placebo therapy. They underwent coronary angiography, endothelial function testing; measurements of fractional flow reserve (FFR) and coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR); and intravascular ultrasonography (IVUS) of the left anterior descending coronary artery, within 8 weeks of HT. At 1 year, the invasive assessment was repeated. Circulating endothelial progenitor cells (EPCs) were quantified at baseline and 1 year.Plaque volumes at 1 year were similar between the ramipril and placebo groups (162.1 ± 70.5 mm(3) vs. 177.3 ± 94.3 mm(3), respectively; p = 0.73). Patients receiving ramipril had improvement in microvascular function as shown by a significant decrease in IMR (21.4 ± 14.7 to 14.4 ± 6.3; p = 0.001) and increase in CFR (3.8 ± 1.7 to 4.8 ± 1.5; p = 0.017), from baseline to 1 year. This did not occur with IMR (17.4 ± 8.4 to 21.5 ± 20.0; p = 0.72) or CFR (4.1 ± 1.8 to 4.1 ± 2.2; p = 0.60) in the placebo-treated patients. EPCs decreased significantly at 1 year in the placebo group but not in the ramipril group.Ramipril does not slow development of epicardial plaque volume but does stabilize levels of endothelial progenitor cells and improve microvascular function, which have been associated with improved long-term survival after HT. (Angiotensin Converting Enzyme [ACE] Inhibition and Cardiac Allograft Vasculopathy; NCT01078363).

  View details for PubMedID 28595700

• Thalidomide treatment prevents chronic graft rejection after aortic transplantation in rats - an experimental study. Transplant international : official journal of the European Society for Organ Transplantation Miller, K. K., Wang, D. n., Hu, X. n., Hua, X. n., Deuse, T. n., Neofytou, E. n., Renne, T. n., Velden, J. n., Reichenspurner, H. n., Schrepfer, S. n., Bernstein, D. n. 2017; 30 (11): 1181–89

  Abstract

  Cardiac allograft vasculopathy (CAV) affects approximately 30% of cardiac transplant patients at 5 years post-transplantation. To date, there are few CAV treatment or prevention options, none of which are highly effective. The aim of the study was to investigate the effect of thalidomide on the development of CAV. The effect of thalidomide treatment on chronic rejection was assessed in rat orthotopic aortic transplants in allogeneic F344 or syngeneic Lew rats (n = 6 per group). Animals were left untreated or received thalidomide for 30 days post-transplant, and evidence of graft CAV was determined by histology (trichrome and immunohistochemistry) and intragraft cytokine measurements. Animals that received thalidomide treatment post-transplant showed markedly reduced luminal obliteration, with concomitant rescue of smooth muscle cells (SMCs) in the aortic media of grafts. Thalidomide counteracted neointimal hyperplasia by preventing dedifferentiation of vascular SMCs. Measurement of intragraft cytokine levels after thalidomide treatment revealed downregulation of matrix metalloproteinase 8 and monocyte chemotactic protein 1, cytokines involved in tissue remodelling and inflammation, respectively. Importantly, no negative side effects of thalidomide were observed. Thalidomide treatment prevents CAV development in a rodent model and is therefore potentially useful in clinical applications to prevent post-transplant heart rejection.

  View details for PubMedID 28672061

• Dynamics of Viral and Host Immune Cell MicroRNA Expression during Acute Infectious Mononucleosis. Frontiers in microbiology Kaul, V. n., Weinberg, K. I., Boyd, S. D., Bernstein, D. n., Esquivel, C. O., Martinez, O. M., Krams, S. M. 2017; 8: 2666

  Abstract

  Epstein-Barr virus (EBV) is the etiological agent of acute infectious mononucleosis (IM). Since acute IM is a self-resolving disease with most patients regaining health in 1-3 weeks there have been few studies examining molecular signatures in early acute stages of the disease. MicroRNAs (miRNAs) have been shown, however, to influence immune cell function and consequently the generation of antibody responses in IM. In this study, we performed a comprehensive analysis of differentially expressed miRNAs in early stage uncomplicated acute IM. miRNAs were profiled from patient peripheral blood obtained at the time of IM diagnosis and at subsequent time points, and pathway analysis performed to identify important immune and cell signaling pathways. We identified 215 differentially regulated miRNAs at the most acute stage of infection when the patients initially sought medical help. The number of differentially expressed miRNAs decreased to 148 and 68 at 1 and 2 months post-primary infection, with no significantly changed miRNAs identified at 7 months post-infection. Interferon signaling, T and B cell signaling and antigen presentation were the top pathways influenced by the miRNAs associated with IM. Thus, a dynamic and regulated expression profile of miRNA accompanies the early acute immune response, and resolution of infection, in IM.

  View details for PubMedID 29379474

  View details for PubMedCentralID PMC5775229

• New insights into mitral valve dystrophy: a Filamin-A genotype-phenotype and outcome study. European heart journal Le Tourneau, T. n., Le Scouarnec, S. n., Cueff, C. n., Bernstein, D. n., Aalberts, J. J., Lecointe, S. n., Mérot, J. n., Bernstein, J. A., Oomen, T. n., Dina, C. n., Karakachoff, M. n., Desal, H. n., Al Habash, O. n., Delling, F. N., Capoulade, R. n., Suurmeijer, A. J., Milan, D. n., Norris, R. A., Markwald, R. n., Aikawa, E. n., Slaugenhaupt, S. A., Jeunemaitre, X. n., Hagège, A. n., Roussel, J. C., Trochu, J. N., Levine, R. A., Kyndt, F. n., Probst, V. n., Le Marec, H. n., Schott, J. J. 2017

  Abstract

  Filamin-A (FLNA) was identified as the first gene of non-syndromic mitral valve dystrophy (FLNA-MVD). We aimed to assess the phenotype of FLNA-MVD and its impact on prognosis.We investigated the disease in 246 subjects (72 mutated) from four FLNA-MVD families harbouring three different FLNA mutations. Phenotype was characterized by a comprehensive echocardiography focusing on mitral valve apparatus in comparison with control relatives. In this X-linked disease valves lesions were severe in men and moderate in women. Most men had classical features of mitral valve prolapse (MVP), but without chordal rupture. By contrast to regular MVP, mitral leaflet motion was clearly restricted in diastole and papillary muscles position was closer to mitral annulus. Valvular abnormalities were similar in the four families, in adults and young patients from early childhood suggestive of a developmental disease. In addition, mitral valve lesions worsened over time as encountered in degenerative conditions. Polyvalvular involvement was frequent in males and non-diagnostic forms frequent in females. Overall survival was moderately impaired in men (P = 0.011). Cardiac surgery rate (mainly valvular) was increased (33.3 ± 9.8 vs. 5.0 ± 4.9%, P < 0.0001; hazard ratio 10.5 [95% confidence interval: 2.9-37.9]) owing mainly to a lifetime increased risk in men (76.8 ± 14.1 vs. 9.1 ± 8.7%, P < 0.0001).FLNA-MVD is a developmental and degenerative disease with complex phenotypic expression which can influence patient management. FLNA-MVD has unique features with both MVP and paradoxical restricted motion in diastole, sub-valvular mitral apparatus impairment and polyvalvular lesions in males. FLNA-MVD conveys a substantial lifetime risk of valve surgery in men.

  View details for PubMedID 29020406

• Early-Onset Hypertrophic Cardiomyopathy Mutations Significantly Increase the Velocity, Force, and Actin-Activated ATPase Activity of Human beta-Cardiac Myosin CELL REPORTS Adhikari, A. S., Kooiker, K. B., Sarkar, S. S., Liu, C., Bernstein, D., Spudich, J. A., Ruppel, K. M. 2016; 17 (11): 2857-2864

  Abstract

  Hypertrophic cardiomyopathy (HCM) is a heritable cardiovascular disorder that affects 1 in 500 people. A significant percentage of HCM is attributed to mutations in β-cardiac myosin, the motor protein that powers ventricular contraction. This study reports how two early-onset HCM mutations, D239N and H251N, affect the molecular biomechanics of human β-cardiac myosin. We observed significant increases (20%-90%) in actin gliding velocity, intrinsic force, and ATPase activity in comparison to wild-type myosin. Moreover, for H251N, we found significantly lower binding affinity between the S1 and S2 domains of myosin, suggesting that this mutation may further increase hyper-contractility by releasing active motors. Unlike previous HCM mutations studied at the molecular level using human β-cardiac myosin, early-onset HCM mutations lead to significantly larger changes in the fundamental biomechanical parameters and show clear hyper-contractility.

  View details for DOI 10.1016/j.celrep.2016.11.040

  View details for Web of Science ID 000390894700007

  View details for PubMedID 27974200

• The Influence of Race and Common Genetic Variations on Outcomes After Pediatric Heart Transplantation. American journal of transplantation Green, D. J., Brooks, M. M., Burckart, G. J., Chinnock, R. E., Canter, C., Addonizio, L. J., Bernstein, D., Kirklin, J. K., Naftel, D. C., Girnita, D. M., Zeevi, A., Webber, S. A. 2016

  Abstract

  Significant racial disparity remains in the incidence of unfavorable outcomes following heart transplantation. We sought to determine which pediatric posttransplantation outcomes differ by race and whether these can be explained by recipient demographic, clinical, and genetic attributes. Data were collected for 80 black and 450 nonblack pediatric recipients transplanted at 1 of 6 centers between 1993 and 2008. Genotyping was performed for 20 candidate genes. Average follow-up was 6.25 years. Unadjusted 5-year rates for death (p = 0.001), graft loss (p = 0.015), acute rejection with severe hemodynamic compromise (p = 0.001), late rejection (p = 0.005), and late rejection with hemodynamic compromise (p = 0.004) were significantly higher among blacks compared with nonblacks. Black recipients were more likely to be older at the time of transplantation (p < 0.001), suffer from cardiomyopathy (p = 0.004), and have public insurance (p < 0.001), and were less likely to undergo induction therapy (p = 0.0039). In multivariate regression models adjusting for age, sex, cardiac diagnosis, insurance status, and genetic variations, black race remained a significant risk factor for all the above outcomes. These clinical and genetic variables explained only 8-19% of the excess risk observed for black recipients. We have confirmed racial differences in survival, graft loss, and several rejection outcomes following heart transplantation in children, which could not be fully explained by differences in recipient attributes.

  View details for DOI 10.1111/ajt.14153

  View details for PubMedID 27931092

• Regenerative medicine - From stem cell biology to clinical trials for pediatric heart failure PROGRESS IN PEDIATRIC CARDIOLOGY Peral, S., Bernstein, D., Nelson, T. J. 2016; 43: 87–89

  View details for DOI 10.1016/j.ppedcard.2016.07.014

  View details for Web of Science ID 000394676700014

• Nat1 Deficiency Is Associated with Mitochondrial Dysfunction and Exercise Intolerance in Mice CELL REPORTS Chennamsetty, I., Coronado, M., Contrepois, K., Keller, M. P., Carcamo-Orive, I., Sandin, J., Fajardo, G., Whittle, A. J., Fathzadeh, M., Snyder, M., Reaven, G., Attie, A. D., Bernstein, D., Quertermous, T., Knowles, J. W. 2016; 17 (2): 527-540

  Abstract

  We recently identified human N-acetyltransferase 2 (NAT2) as an insulin resistance (IR) gene. Here, we examine the cellular mechanism linking NAT2 to IR and find that Nat1 (mouse ortholog of NAT2) is co-regulated with key mitochondrial genes. RNAi-mediated silencing of Nat1 led to mitochondrial dysfunction characterized by increased intracellular reactive oxygen species and mitochondrial fragmentation as well as decreased mitochondrial membrane potential, biogenesis, mass, cellular respiration, and ATP generation. These effects were consistent in 3T3-L1 adipocytes, C2C12 myoblasts, and in tissues from Nat1-deficient mice, including white adipose tissue, heart, and skeletal muscle. Nat1-deficient mice had changes in plasma metabolites and lipids consistent with a decreased ability to utilize fats for energy and a decrease in basal metabolic rate and exercise capacity without altered thermogenesis. Collectively, our results suggest that Nat1 deficiency results in mitochondrial dysfunction, which may constitute a mechanistic link between this gene and IR.

  View details for DOI 10.1016/j.celrep.2016.09.005

  View details for Web of Science ID 000385850700019

  View details for PubMedID 27705799

  View details for PubMedCentralID PMC5097870

• iPSC-derived cardiomyocytes reveal abnormal TGF-ß signalling in left ventricular non-compaction cardiomyopathy. Nature cell biology Kodo, K., Ong, S., Jahanbani, F., Termglinchan, V., Hirono, K., Inanloorahatloo, K., Ebert, A. D., Shukla, P., Abilez, O. J., Churko, J. M., Karakikes, I., Jung, G., Ichida, F., Wu, S. M., Snyder, M. P., Bernstein, D., Wu, J. C. 2016; 18 (10): 1031-1042

  Abstract

  Left ventricular non-compaction (LVNC) is the third most prevalent cardiomyopathy in children and its pathogenesis has been associated with the developmental defect of the embryonic myocardium. We show that patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from LVNC patients carrying a mutation in the cardiac transcription factor TBX20 recapitulate a key aspect of the pathological phenotype at the single-cell level and this was associated with perturbed transforming growth factor beta (TGF-β) signalling. LVNC iPSC-CMs have decreased proliferative capacity due to abnormal activation of TGF-β signalling. TBX20 regulates the expression of TGF-β signalling modifiers including one known to be a genetic cause of LVNC, PRDM16, and genome editing of PRDM16 caused proliferation defects in iPSC-CMs. Inhibition of TGF-β signalling and genome correction of the TBX20 mutation were sufficient to reverse the disease phenotype. Our study demonstrates that iPSC-CMs are a useful tool for the exploration of pathological mechanisms underlying poorly understood cardiomyopathies including LVNC.

  View details for DOI 10.1038/ncb3411

  View details for PubMedID 27642787

• Advances in pediatric cardiology 2016 CURRENT OPINION IN PEDIATRICS Bernstein, D. 2016; 28 (5): 573–74

  View details for PubMedID 27455384

• Recommendations for genetic testing to reduce the incidence of anthracycline-induced cardiotoxicity. British journal of clinical pharmacology Aminkeng, F., Ross, C. J., Rassekh, S. R., Hwang, S., Rieder, M. J., Bhavsar, A. P., Smith, A., Sanatani, S., Gelmon, K. A., Bernstein, D., Hayden, M. R., Amstutz, U., Carleton, B. C. 2016; 82 (3): 683-695

  Abstract

  Anthracycline-induced cardiotoxicity (ACT) occurs in 57% of treated patients and remains an important limitation of anthracycline-based chemotherapy. In various genetic association studies, potential genetic risk markers for ACT have been identified. Therefore, we developed evidence-based clinical practice recommendations for pharmacogenomic testing to further individualize therapy based on ACT risk.We followed a standard guideline development process, including a systematic literature search, evidence synthesis and critical appraisal, and the development of clinical practice recommendations with an international expert group.RARG rs2229774, SLC28A3 rs7853758 and UGT1A6 rs17863783 variants currently have the strongest and the most consistent evidence for association with ACT. Genetic variants in ABCC1, ABCC2, ABCC5, ABCB1, ABCB4, CBR3, RAC2, NCF4, CYBA, GSTP1, CAT, SULT2B1, POR, HAS3, SLC22A7, SCL22A17, HFE and NOS3 have also been associated with ACT, but require additional validation. We recommend pharmacogenomic testing for the RARG rs2229774 (S427L), SLC28A3 rs7853758 (L461L) and UGT1A6*4 rs17863783 (V209V) variants in childhood cancer patients with an indication for doxorubicin or daunorubicin therapy (Level B - moderate). Based on an overall risk stratification, taking into account genetic and clinical risk factors, we recommend a number of management options including increased frequency of echocardiogram monitoring, follow-up, as well as therapeutic options within the current standard of clinical practice.Existing evidence demonstrates that genetic factors have the potential to improve the discrimination between individuals at higher and lower risk of ACT. Genetic testing may therefore support both patient care decisions and evidence development for an improved prevention of ACT.

  View details for DOI 10.1111/bcp.13008

  View details for PubMedID 27197003

• Mitochondrial remodeling: Rearranging, recycling, and reprogramming CELL CALCIUM Gottlieb, R. A., Bernstein, D. 2016; 60 (2): 88-101

  Abstract

  Mitochondria are highly dynamic and responsive organelles that respond to environmental cues with fission and fusion. They undergo mitophagy and biogenesis, and are subject to extensive post-translational modifications. Calcium plays an important role in regulating mitochondrial functions. Mitochondria play a central role in metabolism of glucose, fatty acids, and amino acids, and generate ATP with effects on redox poise, oxidative stress, pH, and other metabolites including acetyl-CoA and NAD(+) which in turn have effects on chromatin remodeling. The complex interplay of mitochondria, cytosolic factors, and the nucleus ensure a well-coordinated response to environmental stresses.

  View details for DOI 10.1016/j.ceca.2016.04.006

  View details for Web of Science ID 000383007900005

  View details for PubMedID 27130902

• Epigenetic response to environmental stress: Assembly of BRG1-G9a/GLP-DNMT3 repressive chromatin complex on Myh6 promoter in pathologically stressed hearts BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH Han, P., Li, W., Yang, J., Shang, C., Lin, C., Cheng, W., Hang, C. T., Cheng, H., Chen, C., Wong, J., Xiong, Y., Zhao, M., Drakos, S. G., Ghetti, A., Li, D. Y., Bernstein, D., Chen, H. V., Quertermous, T., Chang, C. 2016; 1863 (7): 1772-1781

  Abstract

  Chromatin structure is determined by nucleosome positioning, histone modifications, and DNA methylation. How chromatin modifications are coordinately altered under pathological conditions remains elusive. Here we describe a stress-activated mechanism of concerted chromatin modification in the heart. In mice, pathological stress activates cardiomyocytes to express Brg1 (nucleosome-remodeling factor), G9a/Glp (histone methyltransferase), and Dnmt3 (DNA methyltransferase). Once activated, Brg1 recruits G9a and then Dnmt3 to sequentially assemble repressive chromatin-marked by H3K9 and CpG methylation-on a key molecular motor gene (Myh6), thereby silencing Myh6 and impairing cardiac contraction. Disruption of Brg1, G9a or Dnmt3 erases repressive chromatin marks and de-represses Myh6, reducing stress-induced cardiac dysfunction. In human hypertrophic hearts, BRG1-G9a/GLP-DNMT3 complex is also activated; its level correlates with H3K9/CpG methylation, Myh6 repression, and cardiomyopathy. Our studies demonstrate a new mechanism of chromatin assembly in stressed hearts and novel therapeutic targets for restoring Myh6 and ventricular function. The stress-induced Brg1-G9a-Dnmt3 interactions and sequence of repressive chromatin assembly on Myh6 illustrates a molecular mechanism by which the heart epigenetically responds to environmental signals. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  View details for DOI 10.1016/j.bbamcr.2016.03.002

  View details for PubMedID 26952936

• Na+-sensitive elevation in blood pressure is ENaC independent in diet-induced obesity and insulin resistance AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY Nizar, J. M., Dong, W., McClellan, R. B., Labarca, M., Zhou, Y., Wong, J., Goens, D. G., Zhao, M., Velarde, N., Bernstein, D., Pellizzon, M., Satlin, L. M., Bhalla, V. 2016; 310 (9): F812-F820

  Abstract

  The majority of patients with obesity, insulin resistance, and metabolic syndrome have hypertension, but the mechanisms of hypertension are poorly understood. In these patients, impaired sodium excretion is critical for the genesis of Na(+)-sensitive hypertension, and prior studies have proposed a role for the epithelial Na(+) channel (ENaC) in this syndrome. We characterized high fat-fed mice as a model in which to study the contribution of ENaC-mediated Na(+) reabsorption in obesity and insulin resistance. High fat-fed mice demonstrated impaired Na(+) excretion and elevated blood pressure, which was significantly higher on a high-Na(+) diet compared with low fat-fed control mice. However, high fat-fed mice had no increase in ENaC activity as measured by Na(+) transport across microperfused cortical collecting ducts, electrolyte excretion, or blood pressure. In addition, we found no difference in endogenous urinary aldosterone excretion between groups on a normal or high-Na(+) diet. High fat-fed mice provide a model of metabolic syndrome, recapitulating obesity, insulin resistance, impaired natriuresis, and a Na(+)-sensitive elevation in blood pressure. Surprisingly, in contrast to previous studies, our data demonstrate that high fat feeding of mice impairs natriuresis and produces elevated blood pressure that is independent of ENaC activity and likely caused by increased Na(+) reabsorption upstream of the aldosterone-sensitive distal nephron.

  View details for DOI 10.1152/ajprenal.00265.2015

  View details for Web of Science ID 000375115700003

  View details for PubMedID 26841823

• Compassionate deactivation of ventricular assist devices in pediatric patients JOURNAL OF HEART AND LUNG TRANSPLANTATION Hollander, S. A., Axelrod, D. M., Bernstein, D., Cohen, H. J., Sourkes, B., Reddy, S., Magnus, D., Rosenthal, D. N., Kaufman, B. D. 2016; 35 (5): 564-567

  Abstract

  Despite greatly improved survival in pediatric patients with end-stage heart failure through the use of ventricular assist devices (VADs), heart failure ultimately remains a life-threatening disease with a significant symptom burden. With increased demand for donor organs, liberalizing the boundaries of case complexity, and the introduction of destination therapy in children, more children can be expected to die while on mechanical support. Despite this trend, guidelines on the ethical and pragmatic issues of compassionate deactivation of VAD support in children are strikingly absent. As VAD support for pediatric patients increases in frequency, the pediatric heart failure and palliative care communities must work toward establishing guidelines to clarify the complex issues surrounding compassionate deactivation. Patient, family and clinician attitudes must be ascertained and education regarding the psychological, legal and ethical issues should be provided. Furthermore, pediatric-specific planning documents for use before VAD implantation as well as deactivation checklists should be developed to assist with decision-making at critical points during the illness trajectory. Herein we review the relevant literature regarding compassionate deactivation with a specific focus on issues related to children.

  View details for DOI 10.1016/j.healun.2016.03.020

  View details for Web of Science ID 000376951900004

  View details for PubMedID 27197773

• Human induced pluripotent stem cell-derived cardiomyocytes recapitulate the predilection of breast cancer patients to doxorubicin-induced cardiotoxicity NATURE MEDICINE Burridge, P. W., Li, Y. F., Matsa, E., Wu, H., Ong, S., Sharma, A., Holmstrom, A., Chang, A. C., Coronado, M. J., Ebert, A. D., Knowles, J. W., Telli, M. L., Witteles, R. M., Blau, H. M., Bernstein, D., Altman, R. B., Wu, J. C. 2016; 22 (5): 547-556

  Abstract

  Doxorubicin is an anthracycline chemotherapy agent effective in treating a wide range of malignancies, but it causes a dose-related cardiotoxicity that can lead to heart failure in a subset of patients. At present, it is not possible to predict which patients will be affected by doxorubicin-induced cardiotoxicity (DIC). Here we demonstrate that patient-specific human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) can recapitulate the predilection to DIC of individual patients at the cellular level. hiPSC-CMs derived from individuals with breast cancer who experienced DIC were consistently more sensitive to doxorubicin toxicity than hiPSC-CMs from patients who did not experience DIC, with decreased cell viability, impaired mitochondrial and metabolic function, impaired calcium handling, decreased antioxidant pathway activity, and increased reactive oxygen species production. Taken together, our data indicate that hiPSC-CMs are a suitable platform to identify and characterize the genetic basis and molecular mechanisms of DIC.

  View details for DOI 10.1038/nm.4087

  View details for PubMedID 27089514

• Time-dependent evolution of functional vs. remodeling signaling in induced pluripotent stem cell-derived cardiomyocytes and induced maturation with biomechanical stimulation FASEB JOURNAL Jung, G., Fajardo, G., Ribeiro, A. J., Kooiker, K. B., Coronado, M., Zhao, M., Hu, D., Reddy, S., Kodo, K., Sriram, K., Insel, P. A., Wu, J. C., Pruitt, B. L., Bernstein, D. 2016; 30 (4): 1464-1479

  Abstract

  Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a powerful platform for uncovering disease mechanisms and assessing drugs for efficacy/toxicity. However, the accuracy with which hiPSC-CMs recapitulate the contractile and remodeling signaling of adult cardiomyocytes is not fully known. We used β-adrenergic receptor (β-AR) signaling as a prototype to determine the evolution of signaling component expression and function during hiPSC-CM maturation. In "early" hiPSC-CMs (less than or equal to d 30), β2-ARs are a primary source of cAMP/PKA signaling. With longer culture, β1-AR signaling increases: from 0% of cAMP generation at d 30 to 56.8 ± 6.6% by d 60. PKA signaling shows a similar increase: 15.7 ± 5.2% (d 30), 49.8 ± 0.5% (d 60), and 71.0 ± 6.1% (d 90). cAMP generation increases 9-fold from d 30 to 60, with enhanced coupling to remodeling pathways (e.g., Akt and Ca(2+)/calmodulin-dependent protein kinase type II) and development of caveolin-mediated signaling compartmentalization. By contrast, cardiotoxicity induced by chronic β-AR stimulation, a major component of heart failure, develops much later: 5% cell death at d 30 vs. 55% at d 90. Moreover, β-AR maturation can be accelerated by biomechanical stimulation. The differential maturation of β-AR functional vs. remodeling signaling in hiPSC-CMs has important implications for their use in disease modeling and drug testing. We propose that assessment of signaling be added to the indices of phenotypic maturation of hiPSC-CMs.-Jung, G., Fajardo, G., Ribeiro, A. J. S., Kooiker, K. B., Coronado, M., Zhao, M., Hu, D.-Q., Reddy, S., Kodo, K., Sriram, K., Insel, P. A., Wu, J. C., Pruitt, B. L., Bernstein, D. Time-dependent evolution of functional vs. remodeling signaling in induced pluripotent stem cell-derived cardiomyocytes and induced maturation with biomechanical stimulation.

  View details for DOI 10.1096/fj.15-280982

  View details for Web of Science ID 000372629100009

• Thalidomide Treatment Prevents Chronic Graft Rejection after Transplantation in Rats Miller, K. K., Hua, X., Deuse, T., Hu, X., Neofytou, E., Renne, T., Reichenspurner, H., Schrepfer, S., Bernstein, D. ELSEVIER SCIENCE INC. 2016: S48

  View details for DOI 10.1016/j.healun.2016.01.132

  View details for Web of Science ID 000374718100108

• Poverty Is an Independent Socioeconomic Risk Factor for Death Following Pediatric Heart Transplant Dykes, J. C., Peng, D. M., Almond, C. S., Barkoff, L. M., Kaufman, B., Bernstein, D., Rosenthal, D. N., Hollander, S. A. ELSEVIER SCIENCE INC. 2016: S403–S404

  View details for DOI 10.1016/j.healun.2016.01.1165

  View details for Web of Science ID 000374718101479

• Circulating Cell-Free DNA as a Non-Invasive Marker of Pediatric Heart Transplant Rejection and Immunosuppressive Treatment Khush, K. K., Grskovic, M., Luikart, H., Cohen, G., Strehl, C., Wylie, J., Thompson, K., Christie, B., Collins, J., Hiller, D., Yee, J., Bernstein, D. ELSEVIER SCIENCE INC. 2016: S75

  View details for DOI 10.1016/j.healun.2016.01.205

  View details for Web of Science ID 000374718100181

• Cancer Recurrence and Mortality After Pediatric Heart Transplantation for Anthracycline Cardiomyopathy Bock, M. J., Pahl, E., Rusconi, P. G., Boyle, G. J., Parent, J. J., Twist, C. J., Kirklin, J. K., Pruitt, E., Bernstein, D. ELSEVIER SCIENCE INC. 2016: S20–S21

  View details for DOI 10.1016/j.healun.2016.01.057

  View details for Web of Science ID 000374718100035

• The End-of-Life Experience in Pediatric Heart Transplant Recipients Hollander, S. A., Dykes, J. C., Chen, S., Barkoff, L. M., Rosenthal, D. N., Bernstein, D., Kaufman, B. D. ELSEVIER SCIENCE INC. 2016: S410

  View details for DOI 10.1016/j.healun.2016.01.1184

  View details for Web of Science ID 000374718101497

• De Novo and Rare Variants at Multiple Loci Support the Oligogenic Origins of Atrioventricular Septal Heart Defects. PLoS genetics Priest, J. R., Osoegawa, K., Mohammed, N., Nanda, V., Kundu, R., Schultz, K., Lammer, E. J., Girirajan, S., Scheetz, T., Waggott, D., Haddad, F., Reddy, S., Bernstein, D., Burns, T., Steimle, J. D., Yang, X. H., Moskowitz, I. P., Hurles, M., Lifton, R. P., Nickerson, D., Bamshad, M., Eichler, E. E., Mital, S., Sheffield, V., Quertermous, T., Gelb, B. D., Portman, M., Ashley, E. A. 2016; 12 (4)

  Abstract

  Congenital heart disease (CHD) has a complex genetic etiology, and recent studies suggest that high penetrance de novo mutations may account for only a small fraction of disease. In a multi-institutional cohort surveyed by exome sequencing, combining analysis of 987 individuals (discovery cohort of 59 affected trios and 59 control trios, and a replication cohort of 100 affected singletons and 533 unaffected singletons) we observe variation at novel and known loci related to a specific cardiac malformation the atrioventricular septal defect (AVSD). In a primary analysis, by combining developmental coexpression networks with inheritance modeling, we identify a de novo mutation in the DNA binding domain of NR1D2 (p.R175W). We show that p.R175W changes the transcriptional activity of Nr1d2 using an in vitro transactivation model in HUVEC cells. Finally, we demonstrate previously unrecognized cardiovascular malformations in the Nr1d2tm1-Dgen knockout mouse. In secondary analyses we map genetic variation to protein-interaction networks suggesting a role for two collagen genes in AVSD, which we corroborate by burden testing in a second replication cohort of 100 AVSDs and 533 controls (p = 8.37e-08). Finally, we apply a rare-disease inheritance model to identify variation in genes previously associated with CHD (ZFPM2, NSD1, NOTCH1, VCAN, and MYH6), cardiac malformations in mouse models (ADAM17, CHRD, IFT140, PTPRJ, RYR1 and ATE1), and hypomorphic alleles of genes causing syndromic CHD (EHMT1, SRCAP, BBS2, NOTCH2, and KMT2D) in 14 of 59 trios, greatly exceeding variation in control trios without CHD (p = 9.60e-06). In total, 32% of trios carried at least one putatively disease-associated variant across 19 loci,suggesting that inherited and de novo variation across a heterogeneous group of loci may contribute to disease risk.

  View details for DOI 10.1371/journal.pgen.1005963

  View details for PubMedID 27058611

• The Effect of Pediatric Specific Hypertrophic Cardiomyopathy Mutations on the Biomechanics of Beta Cardiac Myosin Adhikari, A. S., Kooiker, K., Sutton, S., Bernstein, D., Leinwand, L. A., Ruppel, K. M., Spudich, J. A. CELL PRESS. 2016: 295A

  View details for DOI 10.1016/j.bpj.2015.11.1592

  View details for Web of Science ID 000375141600430

• Infection-resistant MRI-visible scaffolds for tissue engineering applications. BioImpacts : BI Mahmoudi, M., Zhao, M., Matsuura, Y., Laurent, S., Yang, P. C., Bernstein, D., Ruiz-Lozano, P., Serpooshan, V. 2016; 6 (2): 111-115

  Abstract

  Tissue engineering utilizes porous scaffolds as template to guide the new tissue growth. Clinical application of scaffolding biomaterials is hindered by implant-associated infection and impaired in vivo visibility of construct in biomedical imaging modalities. We recently demonstrated the use of a bioengineered type I collagen patch to repair damaged myocardium. By incorporating superparamagnetic iron oxide nanoparticles into this patch, here, we developed an MRI-visible scaffold. Moreover, the embedded nanoparticles impeded the growth of Salmonella bacteria in the patch. Conferring anti-infection and MRI-visible activities to the engineered scaffolds can improve their clinical outcomes and reduce the morbidity/mortality of biomaterial-based regenerative therapies.

  View details for DOI 10.15171/bi.2016.16

  View details for PubMedID 27525229

• SHORT DURATION TREATMENT WITH SOFOSBUVIR/VELPATASVIR PLUS GS-9857 IN TREATMENT-NAIVE GENOTYPE 1-6 HCV-INFECTED PATIENTS WITH OR WITHOUT CIRRHOSIS Gane, E. J., Nguyen, M., Kwo, P., Kowdley, K., Reau, N., Jacobson, I., Curry, M., Pearlman, B., Khalid, O., Everson, G., Gordon, S., Poulos, J., Sheikh, A., Bernstein, D., Yang, J. C., Stamm, L. M., An, D., Dvory-Sobol, H., Brainard, D. M., McHutchison, J. G., Tong, M., Tsai, N., Beavers, K. L., Rabinovitz, M., Shiffman, M., Stedman, C., Lawitz, E. ELSEVIER SCIENCE BV. 2016: S758–S759

  View details for Web of Science ID 000399133800063

• Early onset HCM mutations H251N and D239N significantly increase the fundamental biomechanical parameters of human beta-cardiac myosin. Adhikari, A. S., Kooiker, K. B., Liu, C., Sarkar, S. S., Bernstein, D., Spudich, J. A., Ruppel, K. M. AMER SOC CELL BIOLOGY. 2016

  View details for Web of Science ID 000396046900942

• Fk506 Reduces Right Ventricular Cardiac Fibrosis In A Bmp Dependent Manner Spiekerkoetter, E. F., Tian, X., Kuang, J., Sudheendra, D., Reddy, S., Zhao, M., Bernstein, D. AMER THORACIC SOC. 2016

  View details for Web of Science ID 000390749603681

• Time-dependent evolution of functional vs. remodeling signaling in induced pluripotent stem cell-derived cardiomyocytes and induced maturation with biomechanical stimulation. FASEB journal : official publication of the Federation of American Societies for Experimental Biology Jung, G., Fajardo, G., Ribeiro, A. J., Kooiker, K. B., Coronado, M., Zhao, M., Hu, D. Q., Reddy, S., Kodo, K., Sriram, K., Insel, P. A., Wu, J. C., Pruitt, B. L., Bernstein, D. 2015

  Abstract

  Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a powerful platform for uncovering disease mechanisms and assessing drugs for efficacy/toxicity. However, the accuracy with which hiPSC-CMs recapitulate the contractile and remodeling signaling of adult cardiomyocytes is not fully known. We used β-adrenergic receptor (β-AR) signaling as a prototype to determine the evolution of signaling component expression and function during hiPSC-CM maturation. In "early" hiPSC-CMs (less than or equal to d 30), β2-ARs are a primary source of cAMP/PKA signaling. With longer culture, β1-AR signaling increases: from 0% of cAMP generation at d 30 to 56.8 ± 6.6% by d 60. PKA signaling shows a similar increase: 15.7 ± 5.2% (d 30), 49.8 ± 0.5% (d 60), and 71.0 ± 6.1% (d 90). cAMP generation increases 9-fold from d 30 to 60, with enhanced coupling to remodeling pathways (e.g., Akt and Ca(2+)/calmodulin-dependent protein kinase type II) and development of caveolin-mediated signaling compartmentalization. By contrast, cardiotoxicity induced by chronic β-AR stimulation, a major component of heart failure, develops much later: 5% cell death at d 30 vs. 55% at d 90. Moreover, β-AR maturation can be accelerated by biomechanical stimulation. The differential maturation of β-AR functional vs. remodeling signaling in hiPSC-CMs has important implications for their use in disease modeling and drug testing. We propose that assessment of signaling be added to the indices of phenotypic maturation of hiPSC-CMs.-Jung, G., Fajardo, G., Ribeiro, A. J. S., Kooiker, K. B., Coronado, M., Zhao, M., Hu, D.-Q., Reddy, S., Kodo, K., Sriram, K., Insel, P. A., Wu, J. C., Pruitt, B. L., Bernstein, D. Time-dependent evolution of functional vs. remodeling signaling in induced pluripotent stem cell-derived cardiomyocytes and induced maturation with biomechanical stimulation.

  View details for DOI 10.1096/fj.15-280982

  View details for PubMedID 26675706

• Physiologic Mitochondrial Fragmentation is a Cardiac Adaptation to Increased Energy Demand Coronado, M., Fajardo, G., Nguyen, K., Zhao, M., Kooiker, K., Jung, G., Hu, D., Reddy, S., Sandoval, E., Stotland, A., Gottlieb, R., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2015: E123

  View details for Web of Science ID 000371324900007

• Mitochondria shape cardiac metabolism SCIENCE Gottlieb, R. A., Bernstein, D. 2015; 350 (6265): 1162–63

  View details for PubMedID 26785456

• Molecular Mechanisms of Right Ventricular Failure. Circulation Reddy, S., Bernstein, D. 2015; 132 (18): 1734-1742

  Abstract

  An abundance of data has provided insight into the mechanisms underlying the development of left ventricular (LV) hypertrophy and its progression to LV failure. In contrast, there is minimal data on the adaptation of the right ventricle (RV) to pressure and volume overload and the transition to RV failure. This is a critical clinical question, because the RV is uniquely at risk in many patients with repaired or palliated congenital heart disease and in those with pulmonary hypertension. Standard heart failure therapies have failed to improve function or survival in these patients, suggesting a divergence in the molecular mechanisms of RV versus LV failure. Although, on the cellular level, the remodeling responses of the RV and LV to pressure overload are largely similar, there are several key differences: the stressed RV is more susceptible to oxidative stress, has a reduced angiogenic response, and is more likely to activate cell death pathways than the stressed LV. Together, these differences could explain the more rapid progression of the RV to failure versus the LV. This review will highlight known molecular differences between the RV and LV responses to hemodynamic stress, the unique stressors on the RV associated with congenital heart disease, and the need to better understand these molecular mechanisms if we are to develop RV-specific heart failure therapeutics.

  View details for DOI 10.1161/CIRCULATIONAHA.114.012975

  View details for PubMedID 26527692

  View details for PubMedCentralID PMC4635965

• The vulnerable right ventricle. Current opinion in pediatrics Reddy, S., Bernstein, D. 2015; 27 (5): 563-568

  Abstract

  The right ventricle (RV) is uniquely at risk in many patients with repaired or palliated congenital heart disease (CHD) such as tetralogy of Fallot, corrected transposition, single right ventricle, and in those with pulmonary hypertension. These patients live with abnormal cardiac loading conditions throughout their life, predisposing them to right heart failure.Standard heart failure therapies, developed to treat left ventricular failure, have failed to improve function or survival in patients with RV failure, suggesting a divergence in the molecular mechanisms of right versus left ventricular failure. As surgical techniques for repair of the most complex forms of RV-affecting CHDs continue to improve, more children with CHD will survive into adulthood. Long-term survival and quality of life will ultimately depend on our ability to preserve RV function.The purpose of this review is to highlight the differences between the right and left ventricular responses to stress, our current knowledge of how the RV adapts to the unique hemodynamic stressors experienced by patients with CHD, and the need to better understand the molecular mechanisms of RV failure, providing new targets for the development of RV-specific heart failure therapeutics.

  View details for DOI 10.1097/MOP.0000000000000268

  View details for PubMedID 26262580

• Long-term challenges in congenital heart disease CURRENT OPINION IN PEDIATRICS Bernstein, D. 2015; 27 (5): 545–47

  View details for PubMedID 26281037

• Epicardial FSTL1 reconstitution regenerates the adult mammalian heart. Nature Wei, K., Serpooshan, V., Hurtado, C., Diez-Cuñado, M., Zhao, M., Maruyama, S., Zhu, W., Fajardo, G., Noseda, M., Nakamura, K., Tian, X., Liu, Q., Wang, A., Matsuura, Y., Bushway, P., Cai, W., Savchenko, A., Mahmoudi, M., Schneider, M. D., van den Hoff, M. J., Butte, M. J., Yang, P. C., Walsh, K., Zhou, B., Bernstein, D., Mercola, M., Ruiz-Lozano, P. 2015; 525 (7570): 479-485

  Abstract

  The elucidation of factors that activate the regeneration of the adult mammalian heart is of major scientific and therapeutic importance. Here we found that epicardial cells contain a potent cardiogenic activity identified as follistatin-like 1 (Fstl1). Epicardial Fstl1 declines following myocardial infarction and is replaced by myocardial expression. Myocardial Fstl1 does not promote regeneration, either basally or upon transgenic overexpression. Application of the human Fstl1 protein (FSTL1) via an epicardial patch stimulates cell cycle entry and division of pre-existing cardiomyocytes, improving cardiac function and survival in mouse and swine models of myocardial infarction. The data suggest that the loss of epicardial FSTL1 is a maladaptive response to injury, and that its restoration would be an effective way to reverse myocardial death and remodelling following myocardial infarction in humans.

  View details for DOI 10.1038/nature15372

  View details for PubMedID 26375005

• Epicardial FSTL1 reconstitution regenerates the adult mammalian heart NATURE Wei, K., Serpooshan, V., Hurtado, C., Diez-Cunado, M., Zhao, M., Maruyama, S., Zhu, W., Fajardo, G., Noseda, M., Nakamura, K., Tian, X., Liu, Q., Wang, A., Matsuura, Y., Bushway, P., Cai, W., Savchenko, A., Mahmoudi, M., Schneider, M. D., van den Hoff, M. J., Butte, M. J., Yang, P. C., Walsh, K., Zhou, B., Bernstein, D., Mercola, M., Ruiz-Lozano, P. 2015; 525 (7570): 479-?

  Abstract

  The elucidation of factors that activate the regeneration of the adult mammalian heart is of major scientific and therapeutic importance. Here we found that epicardial cells contain a potent cardiogenic activity identified as follistatin-like 1 (Fstl1). Epicardial Fstl1 declines following myocardial infarction and is replaced by myocardial expression. Myocardial Fstl1 does not promote regeneration, either basally or upon transgenic overexpression. Application of the human Fstl1 protein (FSTL1) via an epicardial patch stimulates cell cycle entry and division of pre-existing cardiomyocytes, improving cardiac function and survival in mouse and swine models of myocardial infarction. The data suggest that the loss of epicardial FSTL1 is a maladaptive response to injury, and that its restoration would be an effective way to reverse myocardial death and remodelling following myocardial infarction in humans.

  View details for DOI 10.1038/nature15372

  View details for Web of Science ID 000361599900042

  View details for PubMedID 26375005

• Changes in Risk Profile Over Time in the Population of a Pediatric Heart Transplant Program. Annals of thoracic surgery Reinhartz, O., Maeda, K., Reitz, B. A., Bernstein, D., Luikart, H., Rosenthal, D. N., Hollander, S. A. 2015; 100 (3): 989-994

  Abstract

  Single-center data on pediatric heart transplantation spanning long time frames is sparse. We attempted to analyze how risk profile and pediatric heart transplant survival outcomes at a large center changed over time.We divided 320 pediatric heart transplants done at Stanford University between 1974 and 2014 into three groups by era: the first 20 years (95 transplants), the subsequent 10 years (87 transplants), and the most recent 10 years (138 transplants). Differences in age at transplant, indication, mechanical support, and survival were analyzed.Follow-up was 100% complete. Average age at time of transplantation was 10.4 years, 11.9 years, and 5.6 years in eras 1, 2, and 3, respectively. The percentage of infants who received transplants by era was 21%, 7%, and 18%, respectively. The indication of end-stage congenital heart disease vs cardiomyopathy was 24%, 22%, and 49%, respectively. Only 1 patient (1%) was on mechanical support at transplant in era 1 compared with 15% in era 2 and 30% in era 3. Overall survival was 72% at 5 years and 57% at 10 years. Long-term survival increased significantly with each subsequent era. Patients with cardiomyopathy generally had a survival advantage over those with congenital heart disease.The risk profile of pediatric transplant patients in our institution has increased over time. In the last 10 years, median age has decreased and ventricular assist device support has increased dramatically. Transplantation for end-stage congenital heart disease is increasingly common. Despite this, long-term survival has significantly and consistently improved.

  View details for DOI 10.1016/j.athoracsur.2015.05.111

  View details for PubMedID 26228604

• A coding variant in RARG confers susceptibility to anthracycline-induced cardiotoxicity in childhood cancer NATURE GENETICS Aminkeng, F., Bhavsar, A. P., Visscher, H., Rassekh, S. R., Li, Y., Lee, J. W., Brunham, L. R., Caron, H. N., van Dalen, E. C., Kremer, L. C., van der Pal, H. J., Amstutz, U., Rieder, M. J., Bernstein, D., Carleton, B. C., Hayden, M. R., Ross, C. J. 2015; 47 (9): 1079-?

  Abstract

  Anthracyclines are used in over 50% of childhood cancer treatment protocols, but their clinical usefulness is limited by anthracycline-induced cardiotoxicity (ACT) manifesting as asymptomatic cardiac dysfunction and congestive heart failure in up to 57% and 16% of patients, respectively. Candidate gene studies have reported genetic associations with ACT, but these studies have in general lacked robust patient numbers, independent replication or functional validation. Thus, the individual variability in ACT susceptibility remains largely unexplained. We performed a genome-wide association study in 280 patients of European ancestry treated for childhood cancer, with independent replication in similarly treated cohorts of 96 European and 80 non-European patients. We identified a nonsynonymous variant (rs2229774, p.Ser427Leu) in RARG highly associated with ACT (P = 5.9 × 10(-8), odds ratio (95% confidence interval) = 4.7 (2.7-8.3)). This variant alters RARG function, leading to derepression of the key ACT genetic determinant Top2b, and provides new insight into the pathophysiology of this severe adverse drug reaction.

  View details for DOI 10.1038/ng.3374

  View details for Web of Science ID 000360394100020

  View details for PubMedID 26237429

  View details for PubMedCentralID PMC4552570

• Changes in Risk Profile Over Time in the Population of a Pediatric Heart Transplant Program. Annals of thoracic surgery Reinhartz, O., Maeda, K., Reitz, B. A., Bernstein, D., Luikart, H., Rosenthal, D. N., Hollander, S. A. 2015; 100 (3): 989-995

  Abstract

  Single-center data on pediatric heart transplantation spanning long time frames is sparse. We attempted to analyze how risk profile and pediatric heart transplant survival outcomes at a large center changed over time.We divided 320 pediatric heart transplants done at Stanford University between 1974 and 2014 into three groups by era: the first 20 years (95 transplants), the subsequent 10 years (87 transplants), and the most recent 10 years (138 transplants). Differences in age at transplant, indication, mechanical support, and survival were analyzed.Follow-up was 100% complete. Average age at time of transplantation was 10.4 years, 11.9 years, and 5.6 years in eras 1, 2, and 3, respectively. The percentage of infants who received transplants by era was 21%, 7%, and 18%, respectively. The indication of end-stage congenital heart disease vs cardiomyopathy was 24%, 22%, and 49%, respectively. Only 1 patient (1%) was on mechanical support at transplant in era 1 compared with 15% in era 2 and 30% in era 3. Overall survival was 72% at 5 years and 57% at 10 years. Long-term survival increased significantly with each subsequent era. Patients with cardiomyopathy generally had a survival advantage over those with congenital heart disease.The risk profile of pediatric transplant patients in our institution has increased over time. In the last 10 years, median age has decreased and ventricular assist device support has increased dramatically. Transplantation for end-stage congenital heart disease is increasingly common. Despite this, long-term survival has significantly and consistently improved.

  View details for DOI 10.1016/j.athoracsur.2015.05.111

  View details for PubMedID 26228604

• Task Force 8: Pediatric Cardiology Fellowship Training in Research and Scholarly Activity. SPCTPD/ACC/AAP/AHA. Circulation Mahle, W. T., Murphy, A. M., Li, J. S., Law, Y. M., Newburger, J. W., Daniels, S. R., Bernstein, D., Marino, B. S., Ross, R. D. 2015; 132 (6): e107-13

  View details for DOI 10.1161/CIR.0000000000000199

  View details for PubMedID 25769630

• Task Force 8: Pediatric Cardiology Fellowship Training in Research and Scholarly Activity JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Mahle, W. T., Murphy, A. M., Li, J. S., Law, Y. M., Newburger, J. W., Daniels, S. R., Bernstein, D., Marino, B. S., Ross, R. D. 2015; 66 (6): 740-747

  View details for DOI 10.1016/j.jacc.2015.03.006

  View details for Web of Science ID 000359139600019

  View details for PubMedID 25777636

• Task Force 8: Pediatric Cardiology Fellowship Training in Research and Scholarly Activity CIRCULATION Mahle, W. T., Murphy, A. M., Li, J. S., Law, Y. M., Newburger, J. W., Daniels, S. R., Bernstein, D., Marino, B. S., Ross, R. D. 2015; 132 (6): E107-E113

  View details for DOI 10.1161/CIR.0000000000000199

  View details for Web of Science ID 000359666700011

  View details for PubMedID 25769630

• RNA Sequencing Analysis Detection of a Novel Pathway of Endothelial Dysfunction in Pulmonary Arterial Hypertension AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Rhodes, C. J., Im, H., Cao, A., Hennigs, J. K., Wang, L., Sa, S., Chen, P., Nickel, N. P., Miyagawa, K., Hopper, R. K., Tojais, N. F., Li, C. G., Gu, M., Spiekerkoetter, E., Xian, Z., Chen, R., Zhao, M., Kaschwich, M., del Rosario, P. A., Bernstein, D., Zamanian, R. T., Wu, J. C., Snyder, M. P., Rabinovitch, M. 2015; 192 (3): 356-366

  Abstract

  Pulmonary arterial hypertension is characterized by endothelial dysregulation, but global changes in gene expression have not been related to perturbations in function.RNA sequencing was utilized to discriminate changes in transcriptomes of endothelial cells cultured from lungs of patients with idiopathic pulmonary arterial hypertension vs. controls and to assess the functional significance of major differentially expressed transcripts.The endothelial transcriptomes from seven control and six idiopathic pulmonary arterial hypertension patients' lungs were analyzed. Differentially expressed genes were related to BMPR2 signaling. Those downregulated were assessed for function in cultured cells, and in a transgenic mouse.Fold-differences in ten genes were significant (p<0.05), four increased and six decreased in patients vs.No patient was mutant for BMPR2. However, knockdown of BMPR2 by siRNA in control pulmonary arterial endothelial cells recapitulated six/ten patient-related gene changes, including decreased collagen IV (COL4A1, COL4A2) and ephrinA1 (EFNA1). Reduction of BMPR2 regulated transcripts was related to decreased β-catenin. Reducing COL4A1, COL4A2 and EFNA1 by siRNA inhibited pulmonary endothelial adhesion, migration and tube formation. In mice null for the EFNA1 receptor, EphA2, vs. controls, VEGF receptor blockade and hypoxia caused more severe pulmonary hypertension, judged by elevated right ventricular systolic pressure, right ventricular hypertrophy and loss of small arteries.The novel relationship between BMPR2 dysfunction and reduced expression of endothelial COL4 and EFNA1 may underlie vulnerability to injury in pulmonary arterial hypertension.

  View details for DOI 10.1164/rccm.201408-1528OC

  View details for PubMedID 26030479

• Protein Corona Influences Cell-Biomaterial Interactions in Nanostructured Tissue Engineering Scaffolds ADVANCED FUNCTIONAL MATERIALS Serpooshan, V., Mahmoudi, M., Zhao, M., Wei, K., Sivanesan, S., Motamedchaboki, K., Malkovskiy, A. V., Goldstone, A. B., Cohen, J. E., Yang, P. C., Rajadas, J., Bernstein, D., Woo, Y. J., Ruiz-Lozano, P. 2015; 25 (28): 4379-4389

  Abstract

  Biomaterials are extensively used to restore damaged tissues, in the forms of implants (e.g. tissue engineered scaffolds) or biomedical devices (e.g. pacemakers). Once in contact with the physiological environment, nanostructured biomaterials undergo modifications as a result of endogenous proteins binding to their surface. The formation of this macromolecular coating complex, known as 'protein corona', onto the surface of nanoparticles and its effect on cell-particle interactions are currently under intense investigation. In striking contrast, protein corona constructs within nanostructured porous tissue engineering scaffolds remain poorly characterized. As organismal systems are highly dynamic, it is conceivable that the formation of distinct protein corona on implanted scaffolds might itself modulate cell-extracellular matrix interactions. Here, we report that corona complexes formed onto the fibrils of engineered collagen scaffolds display specific, distinct, and reproducible compositions that are a signature of the tissue microenvironment as well as being indicative of the subject's health condition. Protein corona formed on collagen matrices modulated cellular secretome in a context-specific manner ex-vivo, demonstrating their role in regulating scaffold-cellular interactions. Together, these findings underscore the importance of custom-designing personalized nanostructured biomaterials, according to the biological milieu and disease state. We propose the use of protein corona as in situ biosensor of temporal and local biomarkers.

  View details for DOI 10.1002/adfm.201500875

  View details for Web of Science ID 000358504000001

  View details for PubMedCentralID PMC4978190

• High-throughput Single Cell Tracking of Mitochondrial Function in Cardiomyocytes Fajardo, G., Bezold, K., Meyer, T., Mochly-Rosen, D., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2015

  View details for Web of Science ID 000374552800339

• Aberrant TGF beta Signaling as an Etiology of Left Ventricular Non-compaction Cardiomyopathy Kodo, K., Ong, S., Jahanbani, F., Termglinchan, V., InanlooRahatloo, K., Ebert, A. D., Shukla, P., Abilez, O. J., Churko, J. M., Karakikes, I., Jung, G., Snyder, M. P., Bernstein, D., Wu, J. C. LIPPINCOTT WILLIAMS & WILKINS. 2015

  View details for Web of Science ID 000374552800221

• Innovative tools in the individualized medical therapy for children with heart muscle disease PROGRESS IN PEDIATRIC CARDIOLOGY Khalil, F., Luepkena, R., Laeer, S., Bernstein, D. 2015; 39 (1): 37–41

  View details for DOI 10.1016/j.ppedcard.2015.01.007

  View details for Web of Science ID 000213532400008

• Does the OPTN cPRA Calculator Accurately Predict HLA Antigen Frequencies in Pediatric Donors? Hollander, S. A., Tyan, D., Fernandez-Vina, M. A., Rosenthal, D. N., Bernstein, D., Kaufman, B. D., Chen, S., Barkoff, L., Maeda, K., Almond, C. S. ELSEVIER SCIENCE INC. 2015: S161

  View details for DOI 10.1016/j.healun.2015.01.437

  View details for Web of Science ID 000353251500415

• United Stated Trends in Pediatric Heart Transplantation: Are We Busier or Does It Just Feel That Way? Maeda, K., Rosenthal, D. N., Liu, E., McDonald, N., Kaufman, B., Jensen, K., Barkoff, L., Doan, L. N., Burge, M. E., Schneider, L., Bernstein, D., Almond, C. ELSEVIER SCIENCE INC. 2015: S22

  View details for DOI 10.1016/j.healun.2015.01.047

  View details for Web of Science ID 000353251500037

• Center-Specific Variations in Donor Antigen Frequency: Does the OPTN cPRA Calculator Apply to Your Center? Hollander, S. A., Tyan, D. B., Fernandez-Vina, M., Bernstein, D., McDonald, N., Maeda, K., Kaufman, B. D., May, L. J., Rosenthal, D. N., Almond, C. S. ELSEVIER SCIENCE INC. 2015: S169

  View details for DOI 10.1016/j.healun.2015.01.459

  View details for Web of Science ID 000353251500437

• Quality of life and metrics of achievement in long-term adult survivors of pediatric heart transplant. Pediatric transplantation Hollander, S. A., Chen, S., Luikart, H., Burge, M., Hollander, A. M., Rosenthal, D. N., Maeda, K., Hunt, S. A., Bernstein, D. 2015; 19 (1): 76-81

  Abstract

  Many children who undergo heart transplantation will survive into adulthood. We sought to examine the QOL and capacity for achievement in long-term adult survivors of pediatric heart transplantation. Adults >18 yr of age who received transplants as children (≤18 yr old) and had survived for at least 10 yr post-transplant completed two self-report questionnaires: (i) Ferrans & Powers QLI, in which life satisfaction is reported as an overall score and in four subscale domains and is then indexed from 0 (very dissatisfied) to 1 (very satisfied); and (ii) a "Metrics of Life Achievement" questionnaire regarding income, education, relationships, housing status, and access to health care. A total of 20 subjects completed the survey. The overall mean QLI score was 0.77 ± 0.16. Subjects were most satisfied in the family domain (0.84 ± 0.21) and least satisfied in the psychological/spiritual domain (0.7 ± 0.28). Satisfaction in the domains of health/functioning and socioeconomic were intermediate at 0.78 and 0.76, respectively. Most respondents had graduated from high school, reported a median annual income >$50 000/yr, and lived independently. Adult survivors of pediatric heart transplant report a good QOL and demonstrate the ability to obtain an education, work, and live independently.

  View details for DOI 10.1111/petr.12384

  View details for PubMedID 25388808

• [Pyr-1]-Apelin-13 delivery via nano-liposomal encapsulation attenuates pressure overload-induced cardiac dysfunction BIOMATERIALS Serpooshan, V., Sivanesan, S., Huang, X., Mahmoudi, M., Malkovskiy, A. V., Zhao, M., Inayathullah, M., Wagh, D., Zhang, X. J., Metzler, S., Bernstein, D., Wu, J. C., Ruiz-Lozano, P., Rajadas, J. 2015; 37: 289-298

  Abstract

  Nanoparticle-mediated sustained delivery of therapeutics is one of the highly effective and increasingly utilized applications of nanomedicine. Here, we report the development and application of a drug delivery system consisting of polyethylene glycol (PEG)-conjugated liposomal nanoparticles as an efficient in vivo delivery approach for [Pyr1]-apelin-13 polypeptide. Apelin is an adipokine that regulates a variety of biological functions including cardiac hypertrophy and hypertrophy-induced heart failure. The clinical use of apelin has been greatly impaired by its remarkably short half-life in circulation. Here, we investigate whether [Pyr1]-apelin-13 encapsulation in liposome nanocarriers, conjugated with PEG polymer on their surface, can prolong apelin stability in the blood stream and potentiate apelin beneficial effects in cardiac function. Atomic force microscopy and dynamic light scattering were used to assess the structure and size distribution of drug-laden nanoparticles. [Pyr1]-apelin-13 encapsulation in PEGylated liposomal nanocarriers resulted in sustained and extended drug release both in vitro and in vivo. Moreover, intraperitoneal injection of [Pyr1]-apelin-13 nanocarriers in a mouse model of pressure-overload induced heart failure demonstrated a sustainable long-term effect of [Pyr1]-apelin-13 in preventing cardiac dysfunction. We concluded that this engineered nanocarrier system can serve as a delivery platform for treating heart injuries through sustained bioavailability of cardioprotective therapeutics.

  View details for DOI 10.1016/j.biomaterials.2014.08.045

  View details for Web of Science ID 000346541100028

  View details for PubMedID 25443792

• HLA desensitization with bortezomib in a highly sensitized pediatric patient PEDIATRIC TRANSPLANTATION May, L. J., Yeh, J., Maeda, K., Tyan, D. B., Chen, S., Kaufman, B. D., Bernstein, D., Rosenthal, D. N., Hollander, S. A. 2014; 18 (8): E280-E282

  Abstract

  The proteasome inhibitor bortezomib has been used with variable success in the treatment of AMR following heart transplant. There is limited experience with this agent as a pretransplant desensitizing therapy. We report a case of successful HLA desensitization with a bortezomib-based protocol prior to successful heart transplantation. A nine-yr-old boy with dilated cardiomyopathy, not initially sensitized to HLA (cPRA of zero), required three days of ECMO, followed by implantation of a Heartmate II LVAD. Within six wk, the patient developed de novo class I IgG and C1q complement-fixing HLA antibodies with a cPRA of 100%. Two doses of IVIG (2 g/kg) failed to reduce antibody levels, although two courses of a novel desensitization protocol consisting of rituximab (375 mg/m(2) ), bortezomib (1.3 mg/m(2)  × 5 doses), and plasmapheresis reduced his cPRA to 0% and 87% by the C1q and IgG assays, respectively. He underwent heart transplantation nearly two months later. The patient is now >one yr post-transplant, is free of both AMR and ACR, and has no detectable donor-specific antibodies by IgG or C1q. Proteasome inhibition with bortezomib and plasmapheresis may be an effective therapy for HLA desensitization pretransplant.

  View details for DOI 10.1111/petr.12347

  View details for Web of Science ID 000344360500006

• HLA desensitization with bortezomib in a highly sensitized pediatric patient. Pediatric transplantation May, L. J., Yeh, J., Maeda, K., Tyan, D. B., Chen, S., Kaufman, B. D., Bernstein, D., Rosenthal, D. N., Hollander, S. A. 2014; 18 (8): E280-2

  Abstract

  The proteasome inhibitor bortezomib has been used with variable success in the treatment of AMR following heart transplant. There is limited experience with this agent as a pretransplant desensitizing therapy. We report a case of successful HLA desensitization with a bortezomib-based protocol prior to successful heart transplantation. A nine-yr-old boy with dilated cardiomyopathy, not initially sensitized to HLA (cPRA of zero), required three days of ECMO, followed by implantation of a Heartmate II LVAD. Within six wk, the patient developed de novo class I IgG and C1q complement-fixing HLA antibodies with a cPRA of 100%. Two doses of IVIG (2 g/kg) failed to reduce antibody levels, although two courses of a novel desensitization protocol consisting of rituximab (375 mg/m(2) ), bortezomib (1.3 mg/m(2)  × 5 doses), and plasmapheresis reduced his cPRA to 0% and 87% by the C1q and IgG assays, respectively. He underwent heart transplantation nearly two months later. The patient is now >one yr post-transplant, is free of both AMR and ACR, and has no detectable donor-specific antibodies by IgG or C1q. Proteasome inhibition with bortezomib and plasmapheresis may be an effective therapy for HLA desensitization pretransplant.

  View details for DOI 10.1111/petr.12347

  View details for PubMedID 25174602

• Patient-Specific Pluripotent Stem Cells in Doxorubicin Cardiotoxicity: A New Window Into Personalized Medicine. Progress in pediatric cardiology Bernstein, D., Burridge, P. 2014; 37 (1-2): 23-27

  View details for PubMedID 25530693

• A long noncoding RNA protects the heart from pathological hypertrophy NATURE Han, P., Li, W., Lin, C., Yang, J., Shang, C., Nurnberg, S. T., Jin, K. K., Xu, W., Lin, C., Lin, C., Xiong, Y., Chien, H., Zhou, B., Ashley, E., Bernstein, D., Chen, P., Chen, H. V., Quertermous, T., Chang, C. 2014; 514 (7520): 102-?

  Abstract

  The role of long noncoding RNA (lncRNA) in adult hearts is unknown; also unclear is how lncRNA modulates nucleosome remodelling. An estimated 70% of mouse genes undergo antisense transcription, including myosin heavy chain 7 (Myh7), which encodes molecular motor proteins for heart contraction. Here we identify a cluster of lncRNA transcripts from Myh7 loci and demonstrate a new lncRNA-chromatin mechanism for heart failure. In mice, these transcripts, which we named myosin heavy-chain-associated RNA transcripts (Myheart, or Mhrt), are cardiac-specific and abundant in adult hearts. Pathological stress activates the Brg1-Hdac-Parp chromatin repressor complex to inhibit Mhrt transcription in the heart. Such stress-induced Mhrt repression is essential for cardiomyopathy to develop: restoring Mhrt to the pre-stress level protects the heart from hypertrophy and failure. Mhrt antagonizes the function of Brg1, a chromatin-remodelling factor that is activated by stress to trigger aberrant gene expression and cardiac myopathy. Mhrt prevents Brg1 from recognizing its genomic DNA targets, thus inhibiting chromatin targeting and gene regulation by Brg1. It does so by binding to the helicase domain of Brg1, a domain that is crucial for tethering Brg1 to chromatinized DNA targets. Brg1 helicase has dual nucleic-acid-binding specificities: it is capable of binding lncRNA (Mhrt) and chromatinized--but not naked--DNA. This dual-binding feature of helicase enables a competitive inhibition mechanism by which Mhrt sequesters Brg1 from its genomic DNA targets to prevent chromatin remodelling. A Mhrt-Brg1 feedback circuit is thus crucial for heart function. Human MHRT also originates from MYH7 loci and is repressed in various types of myopathic hearts, suggesting a conserved lncRNA mechanism in human cardiomyopathy. Our studies identify a cardioprotective lncRNA, define a new targeting mechanism for ATP-dependent chromatin-remodelling factors, and establish a new paradigm for lncRNA-chromatin interaction.

  View details for DOI 10.1038/nature13596

  View details for Web of Science ID 000342420800044

  View details for PubMedCentralID PMC4184960

• A long noncoding RNA protects the heart from pathological hypertrophy. Nature Han, P., Li, W., Lin, C., Yang, J., Shang, C., Nurnberg, S. T., Jin, K. K., Xu, W., Lin, C., Lin, C., Xiong, Y., Chien, H., Zhou, B., Ashley, E., Bernstein, D., Chen, P., Chen, H. V., Quertermous, T., Chang, C. 2014; 514 (7520): 102-106

  Abstract

  The role of long noncoding RNA (lncRNA) in adult hearts is unknown; also unclear is how lncRNA modulates nucleosome remodelling. An estimated 70% of mouse genes undergo antisense transcription, including myosin heavy chain 7 (Myh7), which encodes molecular motor proteins for heart contraction. Here we identify a cluster of lncRNA transcripts from Myh7 loci and demonstrate a new lncRNA-chromatin mechanism for heart failure. In mice, these transcripts, which we named myosin heavy-chain-associated RNA transcripts (Myheart, or Mhrt), are cardiac-specific and abundant in adult hearts. Pathological stress activates the Brg1-Hdac-Parp chromatin repressor complex to inhibit Mhrt transcription in the heart. Such stress-induced Mhrt repression is essential for cardiomyopathy to develop: restoring Mhrt to the pre-stress level protects the heart from hypertrophy and failure. Mhrt antagonizes the function of Brg1, a chromatin-remodelling factor that is activated by stress to trigger aberrant gene expression and cardiac myopathy. Mhrt prevents Brg1 from recognizing its genomic DNA targets, thus inhibiting chromatin targeting and gene regulation by Brg1. It does so by binding to the helicase domain of Brg1, a domain that is crucial for tethering Brg1 to chromatinized DNA targets. Brg1 helicase has dual nucleic-acid-binding specificities: it is capable of binding lncRNA (Mhrt) and chromatinized--but not naked--DNA. This dual-binding feature of helicase enables a competitive inhibition mechanism by which Mhrt sequesters Brg1 from its genomic DNA targets to prevent chromatin remodelling. A Mhrt-Brg1 feedback circuit is thus crucial for heart function. Human MHRT also originates from MYH7 loci and is repressed in various types of myopathic hearts, suggesting a conserved lncRNA mechanism in human cardiomyopathy. Our studies identify a cardioprotective lncRNA, define a new targeting mechanism for ATP-dependent chromatin-remodelling factors, and establish a new paradigm for lncRNA-chromatin interaction.

  View details for DOI 10.1038/nature13596

  View details for PubMedID 25119045

• hiPSC Modeling of Inherited Cardiomyopathies. Current treatment options in cardiovascular medicine Jung, G., Bernstein, D. 2014; 16 (7): 320-?

  Abstract

  Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) represent a powerful new model system to study the basic mechanisms of inherited cardiomyopathies. hiPSC-CMs have been utilized to model several cardiovascular diseases, achieving the most success in the inherited arrhythmias, including long QT and Timothy syndromes (Moretti et al. N Engl J Med. 363:1397-409, 2010; Yazawa et al. Nature. 471:230-4, 2011) and arrhythmogenic right ventricular dysplasia (ARVD) (Ma et al. Eur Heart J. 34:1122-33, 2013). Recently, studies have applied hiPSC-CMs to the study of both dilated (DCM) (Sun et al. Sci Transl Med. 4:130ra47, 2012) and hypertrophic (HCM) cardiomyopathies (Lan et al. Cell Stem Cell. 12:101-13, 2013; Carvajal-Vergara et al. Nature. 465:808-12, 2010), providing new insights into basic mechanisms of disease. However, hiPSC-CMs do not recapitulate many of the structural and functional aspects of mature human cardiomyocytes, instead mirroring an immature - embryonic or fetal - phenotype. Much work remains in order to better understand these differences, as well as to develop methods to induce hiPSC-CMs into a fully mature phenotype. Despite these limitations, hiPSC-CMs represent the best current in vitro correlate of the human heart and an invaluable tool in the search for mechanisms underlying cardiomyopathy and for screening new pharmacologic therapies.

  View details for DOI 10.1007/s11936-014-0320-7

  View details for PubMedID 24838688

• Circulating Cell-Free DNA Enables Noninvasive Diagnosis of Heart Transplant Rejection SCIENCE TRANSLATIONAL MEDICINE De Vlaminck, I., Valantine, H. A., Snyder, T. M., Strehl, C., Cohen, G., Luikart, H., Neff, N. F., Okamoto, J., Bernstein, D., Weisshaar, D., Quake, S. R., Khush, K. K. 2014; 6 (241)

  Abstract

  Monitoring allograft health is an important component of posttransplant therapy. Endomyocardial biopsy is the current gold standard for cardiac allograft monitoring but is an expensive and invasive procedure. Proof of principle of a universal, noninvasive diagnostic method based on high-throughput screening of circulating cell-free donor-derived DNA (cfdDNA) was recently demonstrated in a small retrospective cohort. We present the results of a prospective cohort study (65 patients, 565 samples) that tested the utility of cfdDNA in measuring acute rejection after heart transplantation. Circulating cell-free DNA was purified from plasma and sequenced (mean depth, 1.2 giga-base pairs) to quantify the fraction of cfdDNA. Through a comparison with endomyocardial biopsy results, we demonstrate that cfdDNA enables diagnosis of acute rejection after heart transplantation, with an area under the receiver operating characteristic curve of 0.83 and sensitivity and specificity that are comparable to the intrinsic performance of the biopsy itself. This noninvasive genome transplant dynamics approach is a powerful and informative method for routine monitoring of allograft health without incurring the risk, discomfort, and expense of an invasive biopsy.

  View details for DOI 10.1126/scitranslmed.3007803

  View details for Web of Science ID 000338711700003

• Circulating cell-free DNA enables noninvasive diagnosis of heart transplant rejection. Science translational medicine De Vlaminck, I., Valantine, H. A., Snyder, T. M., Strehl, C., Cohen, G., Luikart, H., Neff, N. F., Okamoto, J., Bernstein, D., Weisshaar, D., Quake, S. R., Khush, K. K. 2014; 6 (241): 241ra77-?

  Abstract

  Monitoring allograft health is an important component of posttransplant therapy. Endomyocardial biopsy is the current gold standard for cardiac allograft monitoring but is an expensive and invasive procedure. Proof of principle of a universal, noninvasive diagnostic method based on high-throughput screening of circulating cell-free donor-derived DNA (cfdDNA) was recently demonstrated in a small retrospective cohort. We present the results of a prospective cohort study (65 patients, 565 samples) that tested the utility of cfdDNA in measuring acute rejection after heart transplantation. Circulating cell-free DNA was purified from plasma and sequenced (mean depth, 1.2 giga-base pairs) to quantify the fraction of cfdDNA. Through a comparison with endomyocardial biopsy results, we demonstrate that cfdDNA enables diagnosis of acute rejection after heart transplantation, with an area under the receiver operating characteristic curve of 0.83 and sensitivity and specificity that are comparable to the intrinsic performance of the biopsy itself. This noninvasive genome transplant dynamics approach is a powerful and informative method for routine monitoring of allograft health without incurring the risk, discomfort, and expense of an invasive biopsy.

  View details for DOI 10.1126/scitranslmed.3007803

  View details for PubMedID 24944192

• Use of bio-mimetic three-dimensional technology in therapeutics for heart disease BIOENGINEERED Serpooshan, V., Zhao, M., Metzler, S. A., Wei, K., Shah, P. B., Wang, A., Mahmoudi, M., Malkovskiy, A. V., Rajadas, J., Butte, M. J., Bernstein, D., Ruiz-Lozano, P. 2014; 5 (3)

  Abstract

  Due to the limited self-renewal capacity of cardiomyocytes, the mammalian heart exhibits impaired regeneration and insufficient ability to restore heart function after injury. Cardiovascular tissue engineering is currently considered as a promising alternative therapy to restore the structure and function of the failing heart. Recent evidences suggest that the epicardium may play critical roles in regulation of myocardial development and regeneration. One of the mechanisms has been proposed for the restorative effect of the epicardium is the specific physiomechanical cues that this layer provides to the cardiac cells. In this article we explore whether a new generation of epicardium-mimicking, acellular matrices can be utilized to enhance cardiac healing after injury. The matrix consists of a dense collagen scaffold, with optimized biomechanical properties approaching those of embryonic epicardium. Grafting the epicardial patch onto the ischemic myocardium, promptly post the incidence of infarct, resulted in preserved contractility, attenuated ventricular remodeling, diminished fibrosis, and vascularization within the injured tissue in the adult murine heart.

  View details for DOI 10.4161/bioe.27751

  View details for Web of Science ID 000338494200008

• Use of bio-mimetic three-dimensional technology in therapeutics for heart disease. Bioengineered Serpooshan, V., Zhao, M., Metzler, S. A., Wei, K., Shah, P. B., Wang, A., Mahmoudi, M., Malkovskiy, A. V., Rajadas, J., Butte, M. J., Bernstein, D., Ruiz-Lozano, P. 2014; 5 (3): 193-197

  Abstract

  Due to the limited self-renewal capacity of cardiomyocytes, the mammalian heart exhibits impaired regeneration and insufficient ability to restore heart function after injury. Cardiovascular tissue engineering is currently considered as a promising alternative therapy to restore the structure and function of the failing heart. Recent evidences suggest that the epicardium may play critical roles in regulation of myocardial development and regeneration. One of the mechanisms has been proposed for the restorative effect of the epicardium is the specific physiomechanical cues that this layer provides to the cardiac cells. In this article we explore whether a new generation of epicardium-mimicking, acellular matrices can be utilized to enhance cardiac healing after injury. The matrix consists of a dense collagen scaffold, with optimized biomechanical properties approaching those of embryonic epicardium. Grafting the epicardial patch onto the ischemic myocardium, promptly post the incidence of infarct, resulted in preserved contractility, attenuated ventricular remodeling, diminished fibrosis, and vascularization within the injured tissue in the adult murine heart.

  View details for DOI 10.4161/bioe.27751

  View details for PubMedID 24637710

• Quality of Life and Metrics of Achievement in Long-Term Adult Survivors of Pediatric Heart Transplant Hollander, S. A., Chen, S., Luikart, H., Burge, M., Rosenthal, D. N., Maeda, K., Hunt, S. A., Bernstein, D. ELSEVIER SCIENCE INC. 2014: S110

  View details for DOI 10.1016/j.healun.2014.01.329

  View details for Web of Science ID 000333866700287

• Circulating Cell-Free DNA Is a Non-Invasive Marker of Heart Transplant Rejection De Vlaminck, I., Valantine, H. A., Luikart, H., Weisshaar, D., Bernstein, D., Quake, S. R., Khush, K. K. ELSEVIER SCIENCE INC. 2014: S84

  View details for DOI 10.1016/j.healun.2014.01.261

  View details for Web of Science ID 000333866700218

• Introduction to the Series Challenges and Opportunities in Pediatric Heart Failure and Transplantation CIRCULATION Bernstein, D. 2014; 129 (1): 112–14

  View details for PubMedID 24396014

  View details for PubMedCentralID PMC3893708

• Multi-institutional Study of Outcomes After Pediatric Heart Transplantation: Candidate Gene Polymorphism Analysis of ABCC2. The journal of pediatric pharmacology and therapeutics : JPPT : the official journal of PPAG Burckart, G. J., Figg, W. D., Brooks, M. M., Green, D. J., Troutman, S. M., Ferrell, R., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D., Price, D. K., Sissung, T. M., Girnita, D. M., Zeevi, A., Webber, S. A. 2014; 19 (1): 16-24

  Abstract

  Earlier studies have indicated that the pharmacokinetics of mycophenolic acid (MPA) is influenced by polymorphisms of ABCC2, which encodes for the membrane transporter MRP2. The ABCC2 rs717620 A allele has been associated with enterohepatic recirculation of MPA, and our previous work had correlated the discontinuance of MPA with this allele in pediatric heart transplant patients. Therefore, we hypothesized that the ABCC2 rs717620 A allele would be associated with poorer outcomes including rejection with hemodynamic compromise (RHC), graft failure, and death in the pediatric heart transplant (PHTx) population receiving MPA.PHTx recipients from 6 institutions in the Pediatric Heart Transplantation Study (PHTS) from the period of 1993-2009, receiving MPA therapy, were genotyped for ABCC2 rs717620. Genotyping was accomplished by direct sequencing. Demographic and outcome data were limited to the data routinely collected as part of the PHTS and included RHC and mortality.Two hundred ninety patients were identified who received MPA at some point post transplantation, of which 200 carried the GG genotype, 81 carried the AG genotype, and 9 carried the AA genotype. Follow-up time after transplantation was 6 years. RHC occurred in 76 patients and 18 patients died. In the 281 patients followed up more than 1 year, late RHC (>1 year post transplantation) occurred in 42 patients. While both RHC and late RHC were associated with the ABCC2 rs717620 GG genotype (hazard ratios: 1.80 and 4.57, respectively, p<0.05) in all patients, this association was not significant in PHTx patients receiving only MPA as the antiproliferative agent from the time of transplant (n=142).ABCC2 rs717620 polymorphisms varied within racial groups. As a candidate gene assessment, the ABCC2 rs717620 AG and AA genotypes may be associated with improved, rather than poorer, RHC in PHTx patients receiving MPA therapy. ABCC2 rs717620 polymorphisms should be included in any expanded pharmacogenomic analysis of outcomes after pediatric heart transplantation.

  View details for DOI 10.5863/1551-6776-19.1.16

  View details for PubMedID 24782687

  View details for PubMedCentralID PMC3998963

• Fk506 Prevents Endothelial Mesenchymal Transition In Coronary Artery Endothelial Cells Tian, X., Kuang, J., Sudheendra, D., Campbell, A., Zhao, M., Bernstein, D., Reddy, S., Spiekerkoetter, E. F. AMER THORACIC SOC. 2014

  View details for Web of Science ID 000209838204317

• The effect of bioengineered acellular collagen patch on cardiac remodeling and ventricular function post myocardial infarction. Biomaterials Serpooshan, V., Zhao, M., Metzler, S. A., Wei, K., Shah, P. B., Wang, A., Mahmoudi, M., Malkovskiy, A. V., Rajadas, J., Butte, M. J., Bernstein, D., Ruiz-Lozano, P. 2013; 34 (36): 9048-9055

  Abstract

  Regeneration of the damaged myocardium is one of the most challenging fronts in the field of tissue engineering due to the limited capacity of adult heart tissue to heal and to the mechanical and structural constraints of the cardiac tissue. In this study we demonstrate that an engineered acellular scaffold comprising type I collagen, endowed with specific physiomechanical properties, improves cardiac function when used as a cardiac patch following myocardial infarction. Patches were grafted onto the infarcted myocardium in adult murine hearts immediately after ligation of left anterior descending artery and the physiological outcomes were monitored by echocardiography, and by hemodynamic and histological analyses four weeks post infarction. In comparison to infarcted hearts with no treatment, hearts bearing patches preserved contractility and significantly protected the cardiac tissue from injury at the anatomical and functional levels. This improvement was accompanied by attenuated left ventricular remodeling, diminished fibrosis, and formation of a network of interconnected blood vessels within the infarct. Histological and immunostaining confirmed integration of the patch with native cardiac cells including fibroblasts, smooth muscle cells, epicardial cells, and immature cardiomyocytes. In summary, an acellular biomaterial with specific biomechanical properties promotes the endogenous capacity of the infarcted myocardium to attenuate remodeling and improve heart function following myocardial infarction.

  View details for DOI 10.1016/j.biomaterials.2013.08.017

  View details for PubMedID 23992980

• Genetic Variation Near HCRTR2 Associates With Dramatic Improvement of Heart Function in Patients With Heart Failure Perez, M. V., Pavlovic, A., Wheeler, M. T., Miller, C. L., Thanaporn, P., Dewey, F. E., Pan, S., Absher, D., Cretti, E., Southwick, A., Heidenreich, P., Sedehi, D., Brandimarto, J., Kao, D., Salisbury, H., Chan, K., Rosenthal, D., Bernstein, D., Fowler, M. B., Robbins, R. C., Meyers, R., Meyers, R., Quertermous, T., Cappola, T., Ashley, E. LIPPINCOTT WILLIAMS & WILKINS. 2013

  View details for Web of Science ID 000332162905323

• Temporal response of the human virome to immunosuppression and antiviral therapy. Cell De Vlaminck, I., Khush, K. K., Strehl, C., Kohli, B., Luikart, H., Neff, N. F., Okamoto, J., Snyder, T. M., Cornfield, D. N., Nicolls, M. R., Weill, D., Bernstein, D., Valantine, H. A., Quake, S. R. 2013; 155 (5): 1178-1187

  Abstract

  There are few substantive methods to measure the health of the immune system, and the connection between immune strength and the viral component of the microbiome is poorly understood. Organ transplant recipients are treated with posttransplant therapies that combine immunosuppressive and antiviral drugs, offering a window into the effects of immune modulation on the virome. We used sequencing of cell-free DNA in plasma to investigate drug-virome interactions in a cohort of organ transplant recipients (656 samples, 96 patients) and find that antivirals and immunosuppressants strongly affect the structure of the virome in plasma. We observe marked virome compositional dynamics at the onset of the therapy and find that the total viral load increases with immunosuppression, whereas the bacterial component of the microbiome remains largely unaffected. The data provide insight into the relationship between the human virome, the state of the immune system, and the effects of pharmacological treatment and offer a potential application of the virome state to predict immunocompetence.

  View details for DOI 10.1016/j.cell.2013.10.034

  View details for PubMedID 24267896

• Orthotopic heart transplantation in two infants with histiocytoid cardiomyopathy and left ventricular non-compaction PEDIATRIC TRANSPLANTATION Siehr, S. L., Bernstein, D., Yeh, J., Berry, G. J., Rosenthal, D. N., Hollander, S. A. 2013; 17 (7): E165-E167

  Abstract

  HC is a rare cause of congestive heart failure that typically presents with malignant ventricular arrhythmias in infants, often requiring urgent intervention. Successful heart transplantation in a patient with HC has only been reported once (J Heart Lung Transplant 2004: 23: 902). The combination of HC with concurrent LVNC has only been described three times (Int J Legal Med 2009: 123: 47; Hum Pathol 2005: 36: 403; Pediatr Dev Pathol 2012: 15: 397). We report two rare cases of HC with LVNC in two infants presenting with cardiogenic shock, one requiring ECMO support who was successfully bridged to orthotopic heart transplantation with a Berlin Heart LVAD.

  View details for DOI 10.1111/petr.12141

  View details for Web of Science ID 000325369400004

  View details for PubMedID 24099092

• Deletion of the beta 2-adrenergic receptor prevents the development of cardiomyopathy in mice JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY Fajardo, G., Zhao, M., Urashima, T., Farahani, S., Hu, D., Reddy, S., Bernstein, D. 2013; 63: 155-164

  Abstract

  Beta adrenergic receptor (β-AR) subtypes act through diverse signaling cascades to modulate cardiac function and remodeling. Previous in vitro studies suggest that β1-AR signaling is cardiotoxic whereas β2-AR signaling is cardioprotective, and may be the case during ischemia/reperfusion in vivo. The objective of this study was to assess whether β2-ARs also play a cardioprotective role in the pathogenesis of non-ischemic forms of cardiomyopathy. To dissect the role of β1 vs β2-ARs in modulating MLP (Muscle LIM Protein) cardiomyopathy, we crossbred MLP-/- with β1-/- or β2-/- mice. Deletion of the β2-AR improved survival, cardiac function, exercise capacity and myocyte shortening; by contrast haploinsufficency of the β1-AR reduced survival. Pathologic changes in Ca(2+) handling were reversed in the absence of β2-ARs: peak Ca(2+) and SR Ca(2+) were decreased in MLP-/- and β1+/-/MLP-/- but restored in β2-/-MLP-/-. These changes were associated with reversal of alterations in troponin I and phospholamban phosphorylation. Gi inhibition increased peak and baseline Ca(2+), recapitulating changes observed in the β2-/-/MLP-/-. The L-type Ca(2+) blocker verapamil significantly decreased cardiac function in β2-/-MLP-/- vs WT. We next tested if the protective effects of β2-AR ablation were unique to the MLP model using TAC-induced heart failure. Similar to MLP, β2-/- mice demonstrated delayed progression of heart failure with restoration of myocyte shortening and peak Ca(2+) and Ca(2+) release. Deletion of β2-ARs prevents the development of MLP-/- cardiomyopathy via positive modulation of Ca(2+) due to removal of inhibitory Gi signaling and increased phosphorylation of troponin I and phospholamban. Similar effects were seen after TAC. Unlike previous models where β2-ARs were found to be cardioprotective, in these two models, β2-AR signaling appears to be deleterious, potentially through negative regulation of Ca(2+) dynamics.

  View details for DOI 10.1016/j.yjmcc.2013.07.016

  View details for Web of Science ID 000325387300017

  View details for PubMedID 23920331

  View details for PubMedCentralID PMC3791213

• Lower socioeconomic status is associated with worse outcomes after both listing and transplanting children with heart failure PEDIATRIC TRANSPLANTATION Davies, R. R., Russo, M. J., Reinhartz, O., Maeda, K., Rosenthal, D. N., Chin, C., Bernstein, D., Mallidi, H. R. 2013; 17 (6): 573-581

  Abstract

  The relationship between SES and outcomes surrounding pediatric cardiac transplantation is complex and influenced by recipient race. Broad-based studies of SES have not been performed. A retrospective review of all 5125 primary pediatric heart transplants performed in the United States between 2000 and 2011. Patients were stratified by SES based on zip code of residence and U.S. census data (low SES: 1637; mid-SES: 2253; high SES: 1235). Survival following listing and transplantation was compared across strata. Risk-adjusted long-term mortality on the waitlist was higher among low SES patients (hazard 1.32, CI 1.07-1.63). The relationship between SES and outcomes varied by race. Early risk-adjusted post-transplant outcomes were worst among high SES patients (10.8% vs. low SES: 8.9%, p < 0.05). The incidence of non-compliance was higher among low SES patients (p < 0.0001). Long-term risk-adjusted patient survival was poorer among low (hazard 1.41, CI 1.10-1.80) and mid-SES (1.29, 1.04-1.59) groups. Low SES is associated with worse outcomes on both the waitlist and late following transplantation. Higher SES patients had more complex transplants with higher early mortality. Further research should be directed at identifying and addressing underlying causal factors for these disparities.

  View details for DOI 10.1111/petr.12117

  View details for Web of Science ID 000322317700015

  View details for PubMedID 23834560

• Role of telomere dysfunction in cardiac failure in Duchenne muscular dystrophy. Nature cell biology Mourkioti, F., Kustan, J., Kraft, P., Day, J. W., Zhao, M., Kost-Alimova, M., Protopopov, A., DePinho, R. A., Bernstein, D., Meeker, A. K., Blau, H. M. 2013; 15 (8): 895-904

  Abstract

  Duchenne muscular dystrophy (DMD), the most common inherited muscular dystrophy of childhood, leads to death due to cardiorespiratory failure. Paradoxically, mdx mice with the same genetic deficiency of dystrophin exhibit minimal cardiac dysfunction, impeding the development of therapies. We postulated that the difference between mdx and DMD might result from differences in telomere lengths in mice and humans. We show here that, like DMD patients, mice that lack dystrophin and have shortened telomeres (mdx/mTR(KO)) develop severe functional cardiac deficits including ventricular dilation, contractile and conductance dysfunction, and accelerated mortality. These cardiac defects are accompanied by telomere erosion, mitochondrial fragmentation and increased oxidative stress. Treatment with antioxidants significantly retards the onset of cardiac dysfunction and death of mdx/mTR(KO) mice. In corroboration, all four of the DMD patients analysed had 45% shorter telomeres in their cardiomyocytes relative to age- and sex-matched controls. We propose that the demands of contraction in the absence of dystrophin coupled with increased oxidative stress conspire to accelerate telomere erosion culminating in cardiac failure and death. These findings provide strong support for a link between telomere length and dystrophin deficiency in the etiology of dilated cardiomyopathy in DMD and suggest preventive interventions.

  View details for DOI 10.1038/ncb2790

  View details for PubMedID 23831727

  View details for PubMedCentralID PMC3774175

• FK506 activates BMPR2, rescues endothelial dysfunction, and reverses pulmonary hypertension. journal of clinical investigation Spiekerkoetter, E., Tian, X., Cai, J., Hopper, R. K., Sudheendra, D., Li, C. G., El-Bizri, N., Sawada, H., Haghighat, R., Chan, R., Haghighat, L., de Jesus Perez, V., Wang, L., Reddy, S., Zhao, M., Bernstein, D., Solow-Cordero, D. E., Beachy, P. A., Wandless, T. J., ten Dijke, P., Rabinovitch, M. 2013; 123 (8): 3600-3613

  Abstract

  Dysfunctional bone morphogenetic protein receptor-2 (BMPR2) signaling is implicated in the pathogenesis of pulmonary arterial hypertension (PAH). We used a transcriptional high-throughput luciferase reporter assay to screen 3,756 FDA-approved drugs and bioactive compounds for induction of BMPR2 signaling. The best response was achieved with FK506 (tacrolimus), via a dual mechanism of action as a calcineurin inhibitor that also binds FK-binding protein-12 (FKBP12), a repressor of BMP signaling. FK506 released FKBP12 from type I receptors activin receptor-like kinase 1 (ALK1), ALK2, and ALK3 and activated downstream SMAD1/5 and MAPK signaling and ID1 gene regulation in a manner superior to the calcineurin inhibitor cyclosporine and the FKBP12 ligand rapamycin. In pulmonary artery endothelial cells (ECs) from patients with idiopathic PAH, low-dose FK506 reversed dysfunctional BMPR2 signaling. In mice with conditional Bmpr2 deletion in ECs, low-dose FK506 prevented exaggerated chronic hypoxic PAH associated with induction of EC targets of BMP signaling, such as apelin. Low-dose FK506 also reversed severe PAH in rats with medial hypertrophy following monocrotaline and in rats with neointima formation following VEGF receptor blockade and chronic hypoxia. Our studies indicate that low-dose FK506 could be useful in the treatment of PAH.

  View details for DOI 10.1172/JCI65592

  View details for PubMedID 23867624

• FK506 activates BMPR2, rescues endothelial dysfunction, and reverses pulmonary hypertension. journal of clinical investigation Spiekerkoetter, E., Tian, X., Cai, J., Hopper, R. K., Sudheendra, D., Li, C. G., El-Bizri, N., Sawada, H., Haghighat, R., Chan, R., Haghighat, L., de Jesus Perez, V., Wang, L., Reddy, S., Zhao, M., Bernstein, D., Solow-Cordero, D. E., Beachy, P. A., Wandless, T. J., ten Dijke, P., Rabinovitch, M. 2013; 123 (8): 3600-3613

  Abstract

  Dysfunctional bone morphogenetic protein receptor-2 (BMPR2) signaling is implicated in the pathogenesis of pulmonary arterial hypertension (PAH). We used a transcriptional high-throughput luciferase reporter assay to screen 3,756 FDA-approved drugs and bioactive compounds for induction of BMPR2 signaling. The best response was achieved with FK506 (tacrolimus), via a dual mechanism of action as a calcineurin inhibitor that also binds FK-binding protein-12 (FKBP12), a repressor of BMP signaling. FK506 released FKBP12 from type I receptors activin receptor-like kinase 1 (ALK1), ALK2, and ALK3 and activated downstream SMAD1/5 and MAPK signaling and ID1 gene regulation in a manner superior to the calcineurin inhibitor cyclosporine and the FKBP12 ligand rapamycin. In pulmonary artery endothelial cells (ECs) from patients with idiopathic PAH, low-dose FK506 reversed dysfunctional BMPR2 signaling. In mice with conditional Bmpr2 deletion in ECs, low-dose FK506 prevented exaggerated chronic hypoxic PAH associated with induction of EC targets of BMP signaling, such as apelin. Low-dose FK506 also reversed severe PAH in rats with medial hypertrophy following monocrotaline and in rats with neointima formation following VEGF receptor blockade and chronic hypoxia. Our studies indicate that low-dose FK506 could be useful in the treatment of PAH.

  View details for DOI 10.1172/JCI65592

  View details for PubMedID 23867624

• Altered ubiquitin-proteasome signaling in right ventricular hypertrophy and failure. American journal of physiology. Heart and circulatory physiology Rajagopalan, V., Zhao, M., Reddy, S., Fajardo, G., Wang, X., Dewey, S., Gomes, A. V., Bernstein, D. 2013; 305 (4): H551-62

  Abstract

  Alterations in the ubiquitin-proteasome system (UPS) have been described in left ventricular hypertrophy and failure, although results have been inconsistent. The role of the UPS in right ventricular (RV) hypertrophy (RVH) and RV failure (RVF) is unknown. Given the greater percent increase in RV mass associated with RV afterload stress, as present in many congenital heart lesions, we hypothesized that alterations in the UPS could play an important role in RVH/RVF. UPS expression and activity were measured in the RV from mice with RVH/RVF secondary to pulmonary artery constriction (PAC). Epoxomicin and MG132 were used to inhibit the proteasome, and overexpression of the 11S PA28α subunit was used to activate the proteasome. PAC mice developed RVH (109.3% increase in RV weight to body weight), RV dilation with septal shift, RV dysfunction, and clinical RVF. Proteasomal function (26S β5 chymotrypsin-like activity) was decreased 26% (P < 0.05). Protein expression of 19S subunit Rpt5 (P < 0.05), UCHL1 deubiquitinase (P < 0.0001), and Smurf1 E3 ubiquitin ligase (P < 0.01) were increased, as were polyubiquitinated proteins (P < 0.05) and free-ubiquitins (P = 0.05). Pro-apoptotic Bax was increased (P < 0.0001), whereas anti-apoptotic Bcl-2 decreased (P < 0.05), resulting in a sixfold increase in the Bax/Bcl-2 ratio. Proteasomal inhibition did not accelerate RVF. However, proteasome enhancement by cardiac-specific proteasome overexpression partially improved survival. Proteasome activity is decreased in RVH/RVF, associated with upregulation of key UPS regulators and pro-apoptotic signaling. Enhancement of proteasome function partially attenuates RVF, suggesting that UPS dysfunction contributes to RVF.

  View details for DOI 10.1152/ajpheart.00771.2012

  View details for PubMedID 23729213

• Role of telomere dysfunction in cardiac failure in Duchenne muscular dystrophy NATURE CELL BIOLOGY Mourkioti, F., Kustan, J., Kraft, P., Day, J. W., Zhao, M., Kost-Alimova, M., Protopopov, A., DePinho, R. A., Bernstein, D., Meeker, A. K., Blau, H. M. 2013; 15 (8): 895-U300

  Abstract

  Duchenne muscular dystrophy (DMD), the most common inherited muscular dystrophy of childhood, leads to death due to cardiorespiratory failure. Paradoxically, mdx mice with the same genetic deficiency of dystrophin exhibit minimal cardiac dysfunction, impeding the development of therapies. We postulated that the difference between mdx and DMD might result from differences in telomere lengths in mice and humans. We show here that, like DMD patients, mice that lack dystrophin and have shortened telomeres (mdx/mTR(KO)) develop severe functional cardiac deficits including ventricular dilation, contractile and conductance dysfunction, and accelerated mortality. These cardiac defects are accompanied by telomere erosion, mitochondrial fragmentation and increased oxidative stress. Treatment with antioxidants significantly retards the onset of cardiac dysfunction and death of mdx/mTR(KO) mice. In corroboration, all four of the DMD patients analysed had 45% shorter telomeres in their cardiomyocytes relative to age- and sex-matched controls. We propose that the demands of contraction in the absence of dystrophin coupled with increased oxidative stress conspire to accelerate telomere erosion culminating in cardiac failure and death. These findings provide strong support for a link between telomere length and dystrophin deficiency in the etiology of dilated cardiomyopathy in DMD and suggest preventive interventions.

  View details for DOI 10.1038/ncb2790

  View details for Web of Science ID 000322570900006

  View details for PubMedID 23831727

  View details for PubMedCentralID PMC3774175

• Physiologic and molecular characterization of a murine model of right ventricular volume overload. American journal of physiology. Heart and circulatory physiology Reddy, S., Zhao, M., Hu, D., Fajardo, G., Katznelson, E., Punn, R., Spin, J. M., Chan, F. P., Bernstein, D. 2013; 304 (10): H1314-27

  Abstract

  Pulmonary insufficiency (PI) is a common long-term sequel after repair of tetralogy of Fallot, causing progressive right ventricular (RV) dilation and failure. We describe the physiologic and molecular characteristics of the first murine model of RV volume overload. PI was created by entrapping the pulmonary valve leaflets with sutures. Imaging, catheterization, and exercise testing were performed at 1, 3, and 6 mo and compared with sham controls. RNA from the RV free wall was hybridized to Agilent whole genome oligonucleotide microarrays. Volume overload resulted in RV enlargement, decreased RV outflow tract shortening fraction at 1 mo followed by normalization at 3 and 6 mo (39 ± 2, 44 ± 2, and 41 ± 2 vs. 46 ± 3% in sham), early reversal of early and late diastolic filling velocities (E/A ratio) followed by pseudonormalization (0.87 ± 0.08, 0.82 ± 0.08, and 0.96 ± 0.08 vs. 1.04 ± 0.03; P < 0.05), elevated end-diastolic pressure (7.6 ± 0.7, 6.9 ± 0.8, and 7 ± 0.5 vs. 2.7 ± 0.2 mmHg; P < 0.05), and decreased exercise duration (26 ± 0.4, 26 ± 1, and 22 ± 1.3 vs. 30 ± 1.1 min; P < 0.05). Subendocardial RV fibrosis was evident by 1 mo. At 1 mo, 372 genes were significantly downregulated. Mitochondrial pathways and G protein-coupled receptor signaling were the most represented categories. At 3 mo, 434 genes were upregulated and 307 downregulated. While many of the same pathways continued to be downregulated, TNF-α, transforming growth factor-β(1) (TGF-β(1)), p53-signaling, and extracellular matrix (ECM) remodeling transitioned from down- to upregulated. We describe a novel murine model of chronic RV volume overload recapitulating aspects of the clinical disease with gene expression changes suggesting early mitochondrial bioenergetic dysfunction, enhanced TGF-β signaling, ECM remodeling, and apoptosis.

  View details for DOI 10.1152/ajpheart.00776.2012

  View details for PubMedID 23504182

• Physiologic and molecular characterization of a murine model of right ventricular volume overload. American journal of physiology. Heart and circulatory physiology Reddy, S., Zhao, M., Hu, D., Fajardo, G., Katznelson, E., Punn, R., Spin, J. M., Chan, F. P., Bernstein, D. 2013; 304 (10): H1314-27

  View details for DOI 10.1152/ajpheart.00776.2012

  View details for PubMedID 23504182

• Abdominal complaints as a common first presentation of heart failure in adolescents with dilated cardiomyopathy AMERICAN JOURNAL OF EMERGENCY MEDICINE Hollander, S. A., Addonizio, L. J., Chin, C., Lamour, J. M., Hsu, D. T., Bernstein, D., Rosenthal, D. N. 2013; 31 (4): 684-686

  Abstract

  We hypothesized that isolated gastrointestinal complaints (abdominal pain, nausea, anorexia, weight loss), in the absence of other symptoms, were a common mode of initial presentation in children with congestive heart failure (CHF).Ninety-eight patients younger than 18 years hospitalized with dilated cardiomyopathy at a single institution between January 1, 2000, and December 31, 2009, were included. Retrospective review of their presenting complaints was recorded and analyzed according to 3 age groups: 0 to 1 year (infants), 1 to 10 years (children), and 11 to 18 years (adolescents) of age.Respiratory symptoms were common in all age groups (range, 56%-63%). Gastrointestinal complaints were also common in all age groups (42%, 28%, and 65%, respectively) and were more frequent than respiratory complaints in adolescents. Adolescents were likely to present with abdominal pain as their only complaint (10/43, 23%). Chest pain, syncope, or cardiac arrest occurred rarely.Abdominal complaints are a common component of the presenting symptom complex of CHF in pediatric dilated cardiomyopathy in all age groups. In adolescents, abdominal complaints occur more frequently than respiratory complaints and often in the absence of any other symptoms. Unlike CHF in adults, chest pain, arrhythmia, or cardiac arrest occurs rarely at presentation in pediatric patients. Recognition of the different presenting symptoms of heart failure in children by primary providers is crucial to ensuring prompt diagnosis and timely initiation of therapy.

  View details for DOI 10.1016/j.ajem.2012.12.009

  View details for Web of Science ID 000316723400010

  View details for PubMedID 23380118

• Intermediate-term outcomes after combined heart-liver transplantation in children with a univentricular heart JOURNAL OF HEART AND LUNG TRANSPLANTATION Hollander, S. A., Reinhartz, O., Maeda, K., Hurwitz, M., Rosenthal, D. N., Bernstein, D. 2013; 32 (3): 368-370

  Abstract

  For patients with end-stage hepatic failure secondary to failing hemodynamics, combined heart-liver transplant (H-LT) remains the only option for long-term survival. We report a series of three pediatric patients who successfully underwent orthotopic H-LT for failed single-ventricle palliation. All three patients are currently living, now two, three, and five years post-transplant, and remain completely free of cardiac cellular allograft rejection despite reduced immunosuppression protocols. One patient, however, did develop acute antibody-mediated rejection in the immediate post-transplant period, suggesting that this protective effect may be less effective in attenuating humoral mechanisms of rejection.

  View details for DOI 10.1016/j.healun.2012.11.023

  View details for Web of Science ID 000315664600014

  View details for PubMedID 23415318

• Sacrificial layer technique for axial force post assay of immature cardiomyocytes BIOMEDICAL MICRODEVICES Taylor, R. E., Kim, K., Sun, N., Park, S., Sim, J. Y., Fajardo, G., Bernstein, D., Wu, J. C., Pruitt, B. L. 2013; 15 (1): 171-181

  Abstract

  Immature primary and stem cell-derived cardiomyocytes provide useful models for fundamental studies of heart development and cardiac disease, and offer potential for patient specific drug testing and differentiation protocols aimed at cardiac grafts. To assess their potential for augmenting heart function, and to gain insight into cardiac growth and disease, tissue engineers must quantify the contractile forces of these single cells. Currently, axial contractile forces of isolated adult heart cells can only be measured by two-point methods such as carbon fiber techniques, which cannot be applied to neonatal and stem cell-derived heart cells because they are more difficult to handle and lack a persistent shape. Here we present a novel axial technique for measuring the contractile forces of isolated immature cardiomyocytes. We overcome cell manipulation and patterning challenges by using a thermoresponsive sacrificial support layer in conjunction with arrays of widely separated elastomeric microposts. Our approach has the potential to be high-throughput, is functionally analogous to current gold-standard axial force assays for adult heart cells, and prescribes elongated cell shapes without protein patterning. Finally, we calibrate these force posts with piezoresistive cantilevers to dramatically reduce measurement error typical for soft polymer-based force assays. We report quantitative measurements of peak contractile forces up to 146 nN with post stiffness standard error (26 nN) far better than that based on geometry and stiffness estimates alone. The addition of sacrificial layers to future 2D and 3D cell culture platforms will enable improved cell placement and the complex suspension of cells across 3D constructs.

  View details for DOI 10.1007/s10544-012-9710-3

  View details for Web of Science ID 000313517800018

  View details for PubMedID 23007494

  View details for PubMedCentralID PMC3545035

• Brg1 governs distinct pathways to direct multiple aspects of mammalian neural crest cell development PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Li, W., Xiong, Y., Shang, C., Twu, K. Y., Hang, C. T., Yang, J., Han, P., Lin, C., Lin, C., Tsai, F., Stankunas, K., Meyer, T., Bernstein, D., Pan, M., Chang, C. 2013; 110 (5): 1738-1743

  Abstract

  Development of the cerebral vessels, pharyngeal arch arteries (PAAs). and cardiac outflow tract (OFT) requires multipotent neural crest cells (NCCs) that migrate from the neural tube to target tissue destinations. Little is known about how mammalian NCC development is orchestrated by gene programming at the chromatin level, however. Here we show that Brahma-related gene 1 (Brg1), an ATPase subunit of the Brg1/Brahma-associated factor (BAF) chromatin-remodeling complex, is required in NCCs to direct cardiovascular development. Mouse embryos lacking Brg1 in NCCs display immature cerebral vessels, aberrant PAA patterning, and shortened OFT. Brg1 suppresses an apoptosis factor, Apoptosis signal-regulating kinase 1 (Ask1), and a cell cycle inhibitor, p21(cip1), to inhibit apoptosis and promote proliferation of NCCs, thereby maintaining a multipotent cell reservoir at the neural crest. Brg1 also supports Myosin heavy chain 11 (Myh11) expression to allow NCCs to develop into mature vascular smooth muscle cells of cerebral vessels. Within NCCs, Brg1 partners with chromatin remodeler Chromodomain-helicase-DNA-binding protein 7 (Chd7) on the PlexinA2 promoter to activate PlexinA2, which encodes a receptor for semaphorin to guide NCCs into the OFT. Our findings reveal an important role for Brg1 and its downstream pathways in the survival, differentiation, and migration of the multipotent NCCs critical for mammalian cardiovascular development.

  View details for DOI 10.1073/pnas.1218072110

  View details for Web of Science ID 000314558100038

  View details for PubMedID 23319608

  View details for PubMedCentralID PMC3562770

• Loss of adenomatous poliposis coli-a3 integrin interaction promotes endothelial apoptosis in mice and humans. Circulation research de Jesus Perez, V. A., Yuan, K., Orcholski, M. E., Sawada, H., Zhao, M., Li, C. G., Tojais, N. F., Nickel, N., Rajagopalan, V., Spiekerkoetter, E., Wang, L., Dutta, R., Bernstein, D., Rabinovitch, M. 2012; 111 (12): 1551-1564

  Abstract

  Pulmonary hypertension (PH) is characterized by progressive elevation in pulmonary pressure and loss of small pulmonary arteries. As bone morphogenetic proteins promote pulmonary angiogenesis by recruiting the Wnt/β-catenin pathway, we proposed that β-catenin activation could reduce loss and induce regeneration of small pulmonary arteries (PAs) and attenuate PH.This study aims to establish the role of β-catenin in protecting the pulmonary endothelium and stimulating compensatory angiogenesis after injury.To assess the impact of β-catenin activation on chronic hypoxia-induced PH, we used the adenomatous polyposis coli (Apc(Min/+)) mouse, where reduced APC causes constitutive β-catenin elevation. Surprisingly, hypoxic Apc(Min/+) mice displayed greater PH and small PA loss compared with control C57Bl6J littermates. PA endothelial cells isolated from Apc(Min/+) demonstrated reduced survival and angiogenic responses along with a profound reduction in adhesion to laminin. The mechanism involved failure of APC to interact with the cytoplasmic domain of the α3 integrin, to stabilize focal adhesions and activate integrin-linked kinase-1 and phospho Akt. We found that PA endothelial cells from lungs of patients with idiopathic PH have reduced APC expression, decreased adhesion to laminin, and impaired vascular tube formation. These defects were corrected in the cultured cells by transfection of APC.We show that APC is integral to PA endothelial cells adhesion and survival and is reduced in PA endothelial cells from PH patient lungs. The data suggest that decreased APC may be a cause of increased risk or severity of PH in genetically susceptible individuals.

  View details for DOI 10.1161/CIRCRESAHA.112.267849

  View details for PubMedID 23011394

  View details for PubMedCentralID PMC3821702

• Loss of Adenomatous Poliposis Coli-alpha 3 Integrin Interaction Promotes Endothelial Apoptosis in Mice and Humans CIRCULATION RESEARCH Perez, V. A., Yuan, K., Orcholski, M. E., Sawada, H., Zhao, M., Li, C. G., Tojais, N. F., Nickel, N., Rajagopalan, V., Spiekerkoetter, E., Wang, L., Dutta, R., Bernstein, D., Rabinovitch, M. 2012; 111 (12): 1551-?

  View details for DOI 10.1161/CIRCRESAHA.112.267849

  View details for Web of Science ID 000311994700047

• Renal function and genetic polymorphisms in pediatric heart transplant recipients JOURNAL OF HEART AND LUNG TRANSPLANTATION Feingold, B., Brooks, M. M., Zeevi, A., Ohmann, E. L., Burckart, G. J., Ferrell, R. E., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D. C., Webber, S. A. 2012; 31 (9): 1003-1008

  Abstract

  Common genetic variations influence rejection, infection, drug metabolism, and side effect profiles after pediatric heart transplantation. Reports in adults suggest that genetic background may influence post-transplant renal function. In this multicenter study, we investigated the association of genetic polymorphisms (GPs) in a panel of candidate genes on renal function in 453 pediatric heart transplant recipients.We performed genotyping for functional GPs in 19 candidate genes. Renal function was determined annually after transplantation by calculation of the estimated glomerular filtration rate (eGFR). Mixed-effects and Cox proportional hazard models were used to assess recipient characteristics and the effect of GPs on longitudinal eGFR and time to eGFR < 60 mL/min/1.73m(2).Mean age at transplantation was 6.2 ± 6.1 years. Mean follow-up was 5.1 ± 2.5 years. Older age at transplant and black race were independently associated with post-transplant renal dysfunction. Univariate analyses showed FASL (C-843T) T allele (p = 0.014) and HO-1 (A326G) G allele (p = 0.0017) were associated with decreased renal function. After adjusting for age and race, these associations were attenuated (FASL, p = 0.075; HO-1, p = 0.053). We found no associations of other GPs with post-transplant renal function, including GPs in TGFβ1, CYP3A5, ABCB1, and ACE.In this multicenter, large, sample of pediatric heart transplant recipients, we found no strong associations between GPs in 19 candidate genes and post-transplant renal function. Our findings contradict reported associations of CYP3A5 and TGFβ1 with renal function and suggest that genotyping for these GPs will not facilitate individualized immunosuppression for the purpose of protecting renal function after pediatric heart transplantation.

  View details for DOI 10.1016/j.healun.2012.05.010

  View details for Web of Science ID 000308120200011

  View details for PubMedID 22789135

  View details for PubMedCentralID PMC3428223

• Murine Model of Chronic Right Ventricular Diastolic Heart Failure Is Associated with Energetic Alterations and Extracellular Matrix Remodeling Basic Cardiovascular Sciences Scientific Session Reddy, S., Zhao, M., Hu, D., Fajardo, G., Katznelson, E., Spin, J., Chan, F. P., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2012

  View details for Web of Science ID 000312506400316

• Ca2+ and Calmodulin-Dependent Protein Kinase II Mediate a Temporal Switch Between Cardiotoxic and Cardioprotective Signaling by beta 2-Adrenergic Receptors Rajagopalan, V., Fajardo, G., Zhao, M., Urashima, T., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2012

  View details for Web of Science ID 000312506400069

• Differential Regulation of Ubiquitin-Proteasomal System in Right Ventricular Versus Left Ventricular Hypertrophy and Failure Basic Cardiovascular Sciences Scientific Session Rajagopalan, V., Zhao, M., Reddy, S., Fajardo, G., Dewey, S., Gomes, A., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2012

  View details for Web of Science ID 000312506400197

• Outcomes of Children Following a First Hospitalization for Dilated Cardiomyopathy CIRCULATION-HEART FAILURE Hollander, S. A., Bernstein, D., Yeh, J., Dao, D., Sun, H. Y., Rosenthal, D. 2012; 5 (4): 437-443

  Abstract

  We hypothesized that children with dilated cardiomyopathy who require hospital admission are at increased risk for death or transplantation during their first hospitalization and in the first year that follows. We also assessed the value of routine data collected during that time to predict death or the need for transplantation prior to discharge and within 1 year of admission.We conducted a retrospective review of 83 pediatric patients with dilated cardiomyopathy whose initial hospitalization fell between 2004 and 2009. The mean age at hospitalization was 7 years. The majority of patients demonstrated moderate or severe left ventricular dysfunction on initial echocardiogram (80%) and/or the need for intravenous inotropes within 7 days of hospital admission (69%). Five patients (6%) died, and 15 (18%) were transplanted in the initial hospitalization. At 1 year, 11/71 (15%) had died, and 27/71 (38%) were transplanted. The overall freedom from death, transplantation, or rehospitalization at 1 year following admission was 21%. Fractional shortening, left ventricular ejection fraction, serum cholesterol, uric acid, mixed venous saturation, and atrial filling pressures were all predictive of death or transplantation during the initial hospitalization. Left ventricular ejection fraction was predictive of death or transplantation at 1 year.The first hospitalization for dilated cardiomyopathy marks a period of high risk for clinical decline, end stage heart failure, and the need for cardiac transplantation. Echocardiographic function and hemodynamic and serum measurements may aid in predicting outcomes. Despite medical management, most patients will be rehospitalized and/or require cardiac transplantation within 1 year of admission.

  View details for DOI 10.1161/CIRCHEARTFAILURE.111.964510

  View details for Web of Science ID 000313578100013

  View details for PubMedID 22570362

• Dynamic microRNA expression during the transition from right ventricular hypertrophy to failure PHYSIOLOGICAL GENOMICS Reddy, S., Zhao, M., Hu, D., Fajardo, G., Hu, S., Ghosh, Z., Rajagopalan, V., Wu, J. C., Bernstein, D. 2012; 44 (10): 562-575

  Abstract

  MicroRNAs (miRs) are small, noncoding RNAs that are emerging as crucial regulators of cardiac remodeling in left ventricular hypertrophy (LVH) and failure (LVF). However, there are no data on their role in right ventricular hypertrophy (RVH) and failure (RVF). This is a critical question given that the RV is uniquely at risk in patients with congenital right-sided obstructive lesions and in those with systemic RVs. We have developed a murine model of RVH and RVF using pulmonary artery constriction (PAC). miR microarray analysis of RV from PAC vs. control demonstrates altered miR expression with gene targets associated with cardiomyocyte survival and growth during hypertrophy (miR 199a-3p) and reactivation of the fetal gene program during heart failure (miR-208b). The transition from hypertrophy to heart failure is characterized by apoptosis and fibrosis (miRs-34, 21, 1). Most are similar to LVH/LVF. However, there are several key differences between RV and LV: four miRs (34a, 28, 148a, and 93) were upregulated in RVH/RVF that are downregulated or unchanged in LVH/LVF. Furthermore, there is a corresponding downregulation of their putative target genes involving cell survival, proliferation, metabolism, extracellular matrix turnover, and impaired proteosomal function. The current study demonstrates, for the first time, alterations in miRs during the process of RV remodeling and the gene regulatory pathways leading to RVH and RVF. Many of these alterations are similar to those in the afterload-stressed LV. miRs differentially regulated between the RV and LV may contribute to the RVs increased susceptibility to heart failure.

  View details for DOI 10.1152/physiolgenomics.00163.2011

  View details for Web of Science ID 000304367600003

  View details for PubMedID 22454450

  View details for PubMedCentralID PMC3426410

• A Multi-Institutional Study of Outcomes after Pediatric Heart Transplantation: Effect of ABCC2 Polymorphisms Burckart, G. J., Figg, W. D., Brooks, M. M., Green, D., Girnita, D. M., Troutman, S., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D., Price, D. K., Zeevi, A., Webber, S. A. WILEY-BLACKWELL. 2012: 270

  View details for Web of Science ID 000303235502041

• Complement Fixation by C1q vs MFI: Detection of Clinically Relevant Antibodies 32nd Annual Meeting and Scientific Sessions of the International-Society-for-Heart-and-Lung-Transplantation / Meeting of the ISHLT Academy - Core Competencies in Mechanical Circulatory Support Castleberry, C. D., Chin, C., Rosenthal, D., Bernstein, D., HOLLANDER, S. A., Tyan, D. ELSEVIER SCIENCE INC. 2012: S139–S140

  View details for Web of Science ID 000302207900392

• Association between Renal Function and Genetic Polymorphisms in Pediatric Heart Transplant Recipients Feingold, B., Brooks, M. M., Zeevi, A., Ohmann, E. L., Burckart, G. J., Ferrell, R. E., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D. C., Webber, S. A. ELSEVIER SCIENCE INC. 2012: S55–S56

  View details for DOI 10.1016/j.healun.2012.01.143

  View details for Web of Science ID 000302207900139

• A Reduced Immunosuppressive Protocol in Highly Sensitized Pediatric Heart Transplant Patients with a C1q Negative Virtual Crossmatch 32nd Annual Meeting and Scientific Sessions of the International-Society-for-Heart-and-Lung-Transplantation / Meeting of the ISHLT Academy - Core Competencies in Mechanical Circulatory Support HOLLANDER, S. A., ANDERSON, M. W., Tyan, D., Castleberry, C., Bernstein, D., Chin, C. ELSEVIER SCIENCE INC. 2012: S209–S210

  View details for Web of Science ID 000302207900606

• Use of the Impella 5.0 as a bridge from ECMO to implantation of the HeartMate II left ventricular assist device in a pediatric patient PEDIATRIC TRANSPLANTATION Hollander, S. A., Reinhartz, O., Chin, C., Yeh, J., Maeda, K., Mallidi, H., Bernstein, D., Rosenthal, D. 2012; 16 (2): 205-206

  View details for DOI 10.1111/j.1399-3046.2011.01578.x

  View details for Web of Science ID 000300709600022

  View details for PubMedID 21923883

• In Vivo Functional and Transcriptional Profiling of Bone Marrow Stem Cells After Transplantation Into Ischemic Myocardium ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Sheikh, A. Y., Huber, B. C., Narsinh, K. H., Spin, J. M., van der Bogt, K., de Almeida, P. E., Ransohoff, K. J., Kraft, D. L., Fajardo, G., Ardigo, D., Ransohoff, J., Bernstein, D., Fischbein, M. P., Robbins, R. C., Wu, J. C. 2012; 32 (1): 92-102

  Abstract

  Clinical trials of bone marrow-derived stem cell therapy for the heart have yielded variable results. The basic mechanism(s) that underlies their potential efficacy remains unknown. In the present study, we evaluated the survival kinetics, transcriptional response, and functional outcome of intramyocardial bone marrow mononuclear cell (BMMC) transplantation for cardiac repair in a murine myocardial infarction model.We used bioluminescence imaging and high-throughput transcriptional profiling to evaluate the in vivo survival kinetics and gene expression changes of transplanted BMMCs after their engraftment into ischemic myocardium. Our results demonstrate short-lived survival of cells following transplant, with less than 1% of cells surviving by 6 weeks posttransplantation. Moreover, transcriptomic analysis of BMMCs revealed nonspecific upregulation of various cell regulatory genes, with a marked downregulation of cell differentiation and maturation pathways. BMMC therapy caused limited improvement of heart function as assessed by echocardiography, invasive hemodynamics, and positron emission tomography. Histological evaluation of cell fate further confirmed findings of the in vivo cell tracking and transcriptomic analysis.Collectively, these data suggest that BMMC therapy, in its present iteration, may be less efficacious than once thought. Additional refinement of existing cell delivery protocols should be considered to induce better therapeutic efficacy.

  View details for DOI 10.1161/ATVBAHA.111.238618

  View details for Web of Science ID 000298288700014

  View details for PubMedID 22034515

  View details for PubMedCentralID PMC3241895

• Pharmacological inhibition of beta IIPKC is cardioprotective in late-stage hypertrophy JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY Ferreira, J. C., Koyanagi, T., Palaniyandi, S. s., Fajardo, G., Churchill, E. N., Budas, G., Disatnik, M., Bernstein, D., Brum, P. C., Mochly-Rosen, D. 2011; 51 (6): 980-987

  Abstract

  We previously found that in the hearts of hypertensive Dahl salt-sensitive rats, βIIPKC levels increase during the transition from compensated cardiac hypertrophy to cardiac dysfunction. Here we showed that a six-week treatment of these hypertensive rats with a βIIPKC-specific inhibitor, βIIV5-3, prolonged their survival by at least 6weeks, suppressed myocardial fibrosis and inflammation, and delayed the transition from compensated hypertrophy to cardiac dysfunction. In addition, changes in the levels of the Ca(2+)-handling proteins, SERCA2 and the Na(+)/Ca(2+) exchanger, as well as troponin I phosphorylation, seen in the control-treated hypertensive rats were not observed in the βΙΙPKC-treated rats, suggesting that βΙΙPKC contributes to the regulation of calcium levels in the myocardium. In contrast, treatment with the selective inhibitor of βIPKC, an alternative spliced form of βIIPKC, had no beneficial effects in these rats. We also found that βIIV5-3, but not βIV5-3, improved calcium handling in isolated rat cardiomyocytes and enhanced contractility in isolated rat hearts. In conclusion, our data using an in vivo model of cardiac dysfunction (late-phase hypertrophy), suggest that βIIPKC contributes to the pathology associated with heart failure and thus an inhibitor of βIIPKC may be a potential treatment for this disease.

  View details for DOI 10.1016/j.yjmcc.2011.08.025

  View details for PubMedID 21920368

• beta 2-adrenergic receptors mediate cardioprotection through crosstalk with mitochondrial cell death pathways JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY Fajardo, G., Zhao, M., Berry, G., Wong, L., Mochly-Rosen, D., Bernstein, D. 2011; 51 (5): 781-789

  Abstract

  β-adrenergic receptors (β-ARs) modulate cardiotoxicity/cardioprotection through crosstalk with multiple signaling pathways. We have previously shown that β2-ARs are cardioprotective during exposure to oxidative stress induced by doxorubicin (DOX). DOX cardiotoxicity is mediated in part through a Ca(2+)-dependent opening of the mitochondrial permeability transition (MPT), however the signals linking a cell surface receptor like the β2-AR to regulators of mitochondrial function are not clear. The objective of this study was to assess mechanisms of crosstalk between β2-ARs and mitochondrial cell death pathways. DOX administered to WT mice resulted in no acute mortality, however 85% of β2-/- mice died within 30 min. Several pro- and anti-survival pathways were altered. The pro-survival kinase, εPKC, was decreased by 64% in β2-/- after DOX vs WT (p<0.01); the εPKC activator ψεRACK partially rescued these mice (47% reduction in mortality). Activity of the pro-survival kinase Akt decreased by 76% in β2-/- after DOX vs WT (p<0.01). The α1-antagonist prazosin restored Akt activity to normal and also partially reversed the mortality (45%). Deletion of the β2-AR increased rate of Ca(2+) release by 75% and peak [Ca(2+)](i) by 20% respectively in isolated cardiomyocytes; the Ca(2+) channel blocker verapamil also partially rescued the β2-/- (26%). Mitochondrial architecture was disrupted and complex I and II activities decreased by 40.9% and 34.6% respectively after DOX only in β2-/-. The MPT blocker cyclosporine reduced DOX mortality by 41% and prazosin plus cyclosporine acted synergistically to decrease mortality by 85%. β2-ARs activate pro-survival kinases and attenuate mitochondrial dysfunction during oxidative stress; absence of β2-ARs enhances cardiotoxicity via negative regulation of survival kinases and enhancement of intracellular Ca(2+), thus predisposing the mitochondria to opening of the MPT.

  View details for DOI 10.1016/j.yjmcc.2011.06.019

  View details for PubMedID 21756913

• Cardiac pressure overload hypertrophy is differentially regulated by beta-adrenergic receptor subtypes AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Zhao, M., Fajardo, G., Urashima, T., Spin, J. M., Poorfarahani, S., Rajagopalan, V., Diem Huynh, D., Connolly, A., Quertermous, T., Bernstein, D. 2011; 301 (4): H1461-H1470

  Abstract

  In isolated myocytes, hypertrophy induced by norepinephrine is mediated via α(1)-adrenergic receptors (ARs) and not β-ARs. However, mice with deletions of both major cardiac α(1)-ARs still develop hypertrophy in response to pressure overload. Our purpose was to better define the role of β-AR subtypes in regulating cardiac hypertrophy in vivo, important given the widespread clinical use of β-AR antagonists and the likelihood that patients treated with these agents could develop conditions of further afterload stress. Mice with deletions of β(1), β(2), or both β(1)- and β(2)-ARs were subjected to transverse aortic constriction (TAC). After 3 wk, β(1)(-/-) showed a 21% increase in heart to body weight vs. sham controls, similar to wild type, whereas β(2)(-/-) developed exaggerated (49% increase) hypertrophy. Only when both β-ARs were ablated (β(1)β(2)(-/-)) was hypertrophy totally abolished. Cardiac function was preserved in all genotypes. Several known inhibitors of cardiac hypertrophy (FK506 binding protein 5, thioredoxin interacting protein, and S100A9) were upregulated in β(1)β(2)(-/-) compared with the other genotypes, whereas transforming growth factor-β(2), a positive mediator of hypertrophy was upregulated in all genotypes except the β(1)β(2)(-/-). In contrast to recent reports suggesting that angiogenesis plays a critical role in regulating cardiac hypertrophy-induced heart failure, we found no evidence that angiogenesis or its regulators (VEGF, Hif1α, and p53) play a role in compensated cardiac hypertrophy. Pressure overload hypertrophy in vivo is dependent on a coordination of signaling through both β(1)- and β(2)-ARs, mediated through several key cardiac remodeling pathways. Angiogenesis is not a prerequisite for compensated cardiac hypertrophy.

  View details for DOI 10.1152/ajpheart.00453.2010

  View details for Web of Science ID 000295360100028

  View details for PubMedID 21705675

  View details for PubMedCentralID PMC3197363

• Familial Cardiac Valvulopathy Due to Filamin A Mutation AMERICAN JOURNAL OF MEDICAL GENETICS PART A Bernstein, J. A., Bernstein, D., Hehr, U., Hudgins, L. 2011; 155A (9): 2236-2241

  Abstract

  We report on the clinical findings in siblings affected by the recently characterized X-linked form of hereditary cardiac valvular dystrophy or cardiac valve disease (OMIM 314400) due to mutations in the FLNA gene and review the literature on this condition. Although FLNA related cardiac valve disease is presumed to be a rare disorder, it is likely underdiagnosed. Several features of this condition may aid in its identification. FLNA related valvular disease can be recognized on the basis of its distinctive inheritance, early age of onset, and frequent multi-valve involvement.

  View details for DOI 10.1002/ajmg.a.34132

  View details for PubMedID 21815255

• Gene Polymorphisms Impact the Risk of Rejection With Hemodynamic Compromise: A Multicenter Study TRANSPLANTATION Girnita, D. M., Ohmann, E. L., Brooks, M. M., Webber, S. A., Burckart, G. J., Ferrell, R. E., Ranganathan, S., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D. C., Zeevi, A. 2011; 91 (12): 1326-1332

  Abstract

  Rejection with hemodynamic compromise (RHC) is associated with high mortality in heart recipients. This study investigates the association between genetic polymorphisms and RHC in pediatric heart recipients.Data from 532 pediatric heart recipients from six centers in the Pediatric Heart Transplant Study were analyzed for time to RHC by recipient race, age at transplantation, and genotype at 13 genetic polymorphisms (TNF-α A-308G, IL-6 G-174C, INF-γ T+874A, IL-10 G-1082A, C-819T, and C-592A; FAS A-670G, FASL C-843T, and ACE I/D; and VEGF A-2578C, C-1451T, C+405G, and -2549 I/D).RHC occurred in 126 (23.7%) patients during the study period. Adjusting for age and race, IL-10 G-1082A, FAS A-670G, and ACE I/D genotypes were associated with RHC. IL-10 G-1082A GG genotype was associated with decreased risk of RHC with an adjusted hazard ratio (HR) of 0.49 (95% confidence interval [CI], 0.27-0.90; P=0.020). FAS A-670G AA genotype was associated with increased risk of RHC with an adjusted HR of 1.84 (95% CI, 1.25-2.69; P=0.002). ACE II genotype was associated with decreased risk of RHC with an adjusted HR of 0.58 (95% CI, 0.36-0.95; P=0.031).Recipients with a high anti-inflammatory and immune-regulatory genetic profile (high interleukin-10) were protected from RHC. Conversely, recipients with a pro-apoptotic genetic profile (high Fas) or high angiotensin-1-converting enzyme producing genotype were at increased risk of RHC. This represents progress toward understanding the genetic risk factors of posttransplantation outcomes in pediatric heart recipients.

  View details for DOI 10.1097/TP.0b013e31821c1e10

  View details for Web of Science ID 000291430500007

  View details for PubMedID 21659963

• Calibrated micropost arrays for biomechanical characterisation of cardiomyocytes MICRO & NANO LETTERS Kim, K., Taylor, R., Sim, J. Y., Park, S., Norman, J., Fajardo, G., Bernstein, D., Pruitt, B. L. 2011; 6 (5): 317-322

  View details for DOI 10.1049/mnl.2011.0031

  View details for Web of Science ID 000290764000007

• GENETIC DETERMINANTS OF DRAMATIC IMPROVEMENT IN LEFT VENTRICULAR FUNCTION IN PATIENTS WITH HEART FAILURE 60th Annual Scientific Session and Expo of the American-College-of-Cardiology (ACC) / I2 Summit / ACCF/Herman K. Gold Young Investigator's Award in Molecular and Cellular Cardiology Perez, M. V., Pavlovic, A., Wheeler, M. T., Dewey, F. E., Bernstein, D., Fowler, M. B., Robbins, R. C., Quertermous, T., Chan, K., Absher, D., Ho, M., Cretti, E., Southwick, A., Rosenthal, D., Myers, R. M., Heidenreich, P., Garrett, L., Sedehi, D., Kao, D., Salisbury, H., Ashley, E. A. ELSEVIER SCIENCE INC. 2011: E2041–E2041

  View details for Web of Science ID 000291695102046

• Lower Socioeconomic Status Predicts Poor Waitlist and Post-Heart Transplant Survival in Children Davies, R. R., Russo, M. J., Reinhartz, O., Maeda, K., Robbins, R. C., Rosenthal, D. N., Chin, C., Bernstein, D., Mallidi, H. S. ELSEVIER SCIENCE INC. 2011: S164

  View details for DOI 10.1016/j.healun.2011.01.493

  View details for Web of Science ID 000288924300480

• Clinical usefulness of a novel C1q assay to detect immunoglobulin G antibodies capable of fixing complement in sensitized pediatric heart transplant patients JOURNAL OF HEART AND LUNG TRANSPLANTATION Chin, C., Chen, G., Sequeria, F., Berry, G., Siehr, S., Bernstein, D., Rosenthal, D., Reinhartz, O., Tyan, D. 2011; 30 (2): 158-163

  Abstract

  Donor-specific antibodies (DSA) against human leukocyte antigens complicate transplantation with the potential for acute antibody-mediated rejection (AMR). Complement-fixing antibodies are required to initiate the complement cascade. Not all DSAs, however, can fix complement.A novel C1q assay was developed to detect the sub-set of immunoglobulin G (IgG) antibodies capable of fixing complement. Sera from 18 pediatric heart transplant patients were analyzed for DSAs using a Luminex platform (Luminex Inc, Austin, TX) and commercially available single-antigen bead assay kits. Biopsy specimens were assessed for AMR using histopathologic criteria and immunohistochemical staining.During the study period, 5 patients had AMR; of these, 2 were C1q virtual crossmatch positive (VXM+) and had persistent C1q DSAs after transplant, and 3 were C1q VXM- but antibody developed immediately after transplant. A positive C1q assay in the immediate post-transplant period had a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 100%, with 100% sensitivity and 100% specificity (Fisher exact p = 0.001). Of 11 patients who were IgG VXM+, 5 had AMR; the IgG VXM had a PPV of 45% and NPV of 100%, with 100% sensitivity and 54% specificity (Fisher exact p = 0.101).The C1q assay can detect a sub-set of antibodies capable of fixing complement and predicts AMR early after transplant. Avoiding only the donor antigens that would be recognized by the C1q assay may accelerate time to transplant by expansion of the donor pool and potentially allows transplantation of previously "incompatible" organs.

  View details for DOI 10.1016/j.healun.2010.08.020

  View details for Web of Science ID 000286545200008

  View details for PubMedID 20951058

• NEW DIRECTIONS IN BASIC RESEARCH IN HYPERTROPHY AND HEART FAILURE: RELEVANCE FOR PEDIATRIC CARDIOLOGY. Progress in pediatric cardiology Bernstein, D. n., Webber, S. n. 2011; 32 (1): 5–9

  View details for PubMedID 21927547

  View details for PubMedCentralID PMC3171751

• THE ROLE OF ß-ADRENERGIC RECEPTORS IN HEART FAILURE: DIFFERENTIAL REGULATION OF CARDIOTOXICITY AND CARDIOPROTECTION. Progress in pediatric cardiology Bernstein, D., Fajardo, G., Zhao, M. 2011; 31 (1): 35-38

  Abstract

  β-adrenergic receptor blockers have demonstrated significant survival benefit and have become standard therapy for adults with dilated cardiomyopathy, although their efficacy in pediatric patients is still unproven. Recent data suggests that the two major cardiac β-adrenergic receptor subtypes (β1 and β2) couple differentially to intracellular signaling pathways regulating contractility and remodeling. This has led some to suggest that the β1 receptor is the "cardiotoxic subtype" whereas the β2 receptor is "cardioprotective." Given this paradigm, there could be situations where subtype selective β-blockade or even subtype selective β-stimulation might be beneficial. However, since most of these studies have been performed in isolated cardiomyocytes, their application to clinical practice is unclear. To better understand the roles of β1- vs. β2-receptors in the pathogenesis of clinical cardiomyopathy, we and others have taken advantage of several well-characterized murine models of cardiovascular disease. These studies demonstrate that β-receptor regulation of the balance between cardioprotection and cardiotoxicity is even more complex than previously appreciated: the role of each β-receptor subtype may vary depending on the specific cardiac stressor involved (e.g. ischemia, pressure overload, genetic mutation, cardiotoxin). Furthermore, the remodeling effects of β-receptor signaling have a temporal component, depending on whether a cardiac stress is acute vs. chronic.

  View details for PubMedID 21765627

• Association of genetic polymorphisms and risk of Late post-transplantation infection in pediatric heart recipients JOURNAL OF HEART AND LUNG TRANSPLANTATION Ohmann, E. L., Brooks, M. M., Webber, S. A., Girnita, D. M., Ferrell, R. E., Burckart, G. J., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D. C., Zeevi, A. 2010; 29 (12): 1342-1351

  Abstract

  Late infections are common causes of morbidity and mortality after pediatric heart transplantation. In this multicenter study from 6 centers, we investigated the association between genetic polymorphisms (GPs) in immune response genes and late post-transplantation infections in 524 patients.Late infection was defined as a clinical infectious process occurring >60 days after transplantation and requiring hospitalization, intravenous antimicrobial therapy, or a life-threatening infection requiring oral therapy. All patients provided a blood sample for GP analyses of 18 GPs in cytokine, growth factor, and effector molecule genes by single specific primer-polymerase chain reaction and/or sequencing. Significant associations in univariable analyses were tested in multivariable Cox regression models.Late infection was common, with 48.7% of patients experiencing ≥ 1 late infection, 25.2% had ≥ 1 late bacterial infection, and 30.5% had ≥ 1 late viral infection. Older age at transplantation was a protective factor for late infection, both bacterial and viral (hazard ratio [HR] 0.89-0.92 per 1-year age increase, p < 0.001). Adjusting for age, race, and transplant etiology, late bacterial infection was associated with HMOX1 A+326G AG and GG genotypes (HR, 2.41, 95% confidence interval [CI] 1.35-4.30; p = 0.003) and GZMB A-295G AA genotype (HR, 1.47; 95% CI; 1.03-2.1; p = 0.036). Late viral infection was associated with FAS A-670G GG genotype (HR, 1.42; 95% CI, 1.00-2.00; p = 0.050) in the adjusted model and with CTLA4 A+49G AA and AG genotypes (HR, 1.49; 95% CI, 1.02-2.19; p = 0.041) in univariable analysis.We found an association between late bacterial infection and GP of HMOX1, which may control macrophage activation. A weaker association was also found between late viral infection and GP of CTLA4, a regulator of T-cell activation. This represents progress toward understanding the clinical and genetic risk factors of outcomes after transplantation.

  View details for DOI 10.1016/j.healun.2010.07.013

  View details for Web of Science ID 000285220700004

  View details for PubMedID 20869265

• Physiologic and Molecular Characterization of a Murine Model of Pulmonary Insufficiency Reddy, S., Zhao, M., Fajardo, G., Spin, J. M., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2010

  View details for Web of Science ID 000208231602682

• Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS)-Defined Morbidity and Mortality Associated With Pediatric Ventricular Assist Device Support at a Single US Center The Stanford Experience CIRCULATION-HEART FAILURE Stein, M. L., Robbins, R., Sabati, A. A., Reinhartz, O., Chin, C., Liu, E., Bernstein, D., Roth, S., Wright, G., Reitz, B., Rosenthal, D. 2010; 3 (6): 682-688

  Abstract

  The use of ventricular assist devices (VADs) to bridge pediatric patients to heart transplantation has increased dramatically over the last 15 years. In this report, we present the largest US single-center report of pediatric VAD use to date. We present detailed descriptions of morbidity and mortality associated with VAD support, using standard Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) criteria for pediatrics to facilitate the comparison of these results to other studies.We retrospectively identified 25 patients younger than 18 years with 27 episodes of mechanical circulatory support using VADs as bridge to heart transplantation from January 1998 to December 2007. Survival to transplant for the entire cohort was 74%. The most common major morbidities, as defined by INTERMACS criteria for a pediatric population, were respiratory failure, major localized infections, major bleeding events, hepatic dysfunction, and right heart failure. Major neurological events occurred in 48% of the study population. The median time to the first occurrence of an adverse event was less than 14 days for respiratory failure, right heart failure, major localized infection, and major bleeding. Patients who died before transplantation had significantly more adverse events per day of support than did those who were successfully transplanted. Episodes of major bleeding, tamponade, acute renal failure, respiratory failure, and right heart failure were all associated with increased risk of mortality.INTERMACS criteria can be successfully used to analyze pediatric VAD outcomes. These data serve as a baseline for future studies of VAD support in children and indicate good survival rates but considerable morbidity.

  View details for DOI 10.1161/CIRCHEARTFAILURE.109.918672

  View details for PubMedID 20807863

• Behcet's disease and heart transplantation: A word of caution JOURNAL OF HEART AND LUNG TRANSPLANTATION Hollander, S. A., Yasnovsky, J. R., Reinhartz, O., Chan, F., Sandborg, C., Hunt, S., Bernstein, D., Chin, C. 2010; 29 (11): 1306-1308

  Abstract

  Behcet's disease is a rare autoimmune disease characterized by oral and genital ulcers, and by multisystem disease, including arthritis, neurologic complications and vasculitis. Large-vessel and coronary artery aneurysms are often an indication for surgery, but the return of aneurysms, thrombosis, and the tendency to exhibit an exaggerated inflammatory response at puncture sites (pathergy) complicate surgical recovery. As such, cardiac transplantation, which requires atrial and large-vessel anastomoses, has not been reported in patients with Behcet's disease. We report the first orthotopic heart transplant with >1-year survival in a patient with Behcet's disease despite major complications. The investigators remain pessimistic about cardiac transplantation in patients with Behcet's disease until advances in preventing recurrent vascular pathology ensue.

  View details for DOI 10.1016/j.healun.2010.07.010

  View details for PubMedID 20822920

• The Right Ventricular Hypertrophic Response Does Not miRror the Left Ventricle 14th Annual Scientific Meeting of the Heart-Failure-Society-of-America Reddy, S., Zhao, M., Rajagopalan, V., Fajardo, G., Ghosh, Z., Wu, J., Bernstein, D. CHURCHILL LIVINGSTONE INC MEDICAL PUBLISHERS. 2010: S9–S10

  View details for Web of Science ID 000281501800024

• THE RESUSCITATED NHBD HEART IS FUNCTIONALLY SUPERIOR TO THE BRAINSTEM DEAD DONOR HEART Ali, A., Fajardo, G., Tsuda, S., Budas, G., Ali, Z., Quertermous, T., Bernstein, D., Robbins, R., Fischbein, M., Large, S., Ashley, E. WILEY-BLACKWELL. 2010: 7

  View details for Web of Science ID 000277330800033

• The Impact of HLA-G Polymorphism on Acute Rejection in Pediatric Heart Transplant Recipients Zeevi, A., Brooks, M., Girnita, D., Ferrell, R., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J., Naftel, D., Webber, S. ELSEVIER SCIENCE INC. 2010: S106

  View details for DOI 10.1016/j.healun.2009.11.328

  View details for Web of Science ID 000274756100314

• Daclizumab Is an Efficacious Induction Agent for Highly Sensitized Pediatric Heart Transplant Recipients Auerbach, S. R., Rosenthal, D. N., Bernstein, D., Chin, C. ELSEVIER SCIENCE INC. 2010: S172

  View details for DOI 10.1016/j.healun.2009.11.544

  View details for Web of Science ID 000274756100525

• Antibody Mediated Rejection (AMR) Predicted by New C1q Assay Chin, C., Chen, G., Siehr, S., Rosenthal, D., Reinhartz, O., Bernstein, D., Sequeira, F., Tyan, D. ELSEVIER SCIENCE INC. 2010: S107

  View details for DOI 10.1016/j.healun.2009.11.332

  View details for Web of Science ID 000274756100318

• The Effect of Apelin on Single Isolated Cardiac Myocytes from Wild-Type and Apelin / APJ KO Mice Bollensdorff, C., Charo, D., Ho, M., Fajardo, G., Bernstein, D., Quertermous, T., Ashley, E., Kohl, P. CELL PRESS. 2010: 710A

  View details for DOI 10.1016/j.bpj.2009.12.3896

  View details for Web of Science ID 000208762007038

• Differential Modulation of Mitochondrial Function in Doxorubicin Cardiotoxicity by beta2-Adrenergic Receptors is Strain Dependent: Role of mtDNA 82nd National Conference and Exhibitions and Scientific Sessions of the American-Heart-Association Fajardo, G., Fan, W., Zhao, M., Wallace, D., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2009: S614–S615

  View details for Web of Science ID 000271831501478

• Endogenous regulation of cardiovascular function by apelin-APJ AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Charo, D. N., Ho, M., Fajardo, G., Kawana, M., Kundu, R. K., Sheikh, A. Y., Finsterbach, T. P., Leeper, N. J., Ernst, K. V., Chen, M. M., Ho, Y. D., Chun, H. J., Bernstein, D., Ashley, E. A., Quertermous, T. 2009; 297 (5): H1904-H1913

  Abstract

  Studies have shown significant cardiovascular effects of exogenous apelin administration, including the potent activation of cardiac contraction. However, the role of the endogenous apelin-APJ pathway is less clear. To study the loss of endogenous apelin-APJ signaling, we generated mice lacking either the ligand (apelin) or the receptor (APJ). Apelin-deficient mice were viable, fertile, and showed normal development. In contrast, APJ-deficient mice were not born in the expected Mendelian ratio, and many showed cardiovascular developmental defects. Under basal conditions, both apelin and APJ null mice that survived to adulthood manifested modest decrements in contractile function. However, with exercise stress both mutant lines demonstrated consistent and striking decreases in exercise capacity. To explain these findings, we explored the role of autocrine signaling in vitro using field stimulation of isolated left ventricular cardiomyocytes lacking either apelin or APJ. Both groups manifested less sarcomeric shortening and impaired velocity of contraction and relaxation with no difference in calcium transient. Taken together, these results demonstrate that endogenous apelin-APJ signaling plays a modest role in maintaining basal cardiac function in adult mice with a more substantive role during conditions of stress. In addition, an autocrine pathway seems to exist in myocardial cells, the ablation of which reduces cellular contraction without change in calcium transient. Finally, differences in the developmental phenotype between apelin and APJ null mice suggest the possibility of undiscovered APJ ligands or ligand-independent effects of APJ.

  View details for DOI 10.1152/ajpheart.00686.2009

  View details for Web of Science ID 000271143400045

  View details for PubMedID 19767528

  View details for PubMedCentralID PMC2781363

• Association of Left Ventricular Dilation at Listing for Heart Transplant With Postlisting and Early Posttransplant Mortality in Children With Dilated Cardiomyopathy CIRCULATION-HEART FAILURE Singh, T. P., Sleeper, L. A., Lipshultz, S., Cinar, A., Canter, C., Webber, S. A., Bernstein, D., Pahl, E., Alvarez, J. A., Wilkinson, J. D., Towbin, J. A., Colan, S. D. 2009; 2 (6): 591-U100

  Abstract

  In patients with dilated cardiomyopathy, the magnitude of cardiac remodeling often correlates with the clinical severity of heart failure. We sought to determine whether measures of left ventricular (LV) dilation and systolic dysfunction in children with dilated cardiomyopathy at the time of listing for cardiac transplantation are associated with survival while waiting for and early after transplant.We analyzed echocardiographic data obtained within 6 months of listing for heart transplant and clinical data from 261 children with dilated cardiomyopathy who were included in both the Pediatric Cardiomyopathy Registry and the Pediatric Heart Transplant Study. Median time to listing after diagnosis was 1.9 months and to transplant after listing was 0.8 months. There were 42 deaths (29 waiting and 13 within 6 months after transplant). We found a significant age-dependent association of LV end-diastolic dimension z score (n=204, 31 deaths) with death controlling for race, transplant status, and medical insurance. The association was strongest for infants younger than 6 months at diagnosis (hazard ratio 1.47, P=0.008) and was not significant in children older than 5 years at diagnosis. A similar interaction was identified between age and LV end-systolic dimension z score (P=0.04). Neither LV function nor mass was associated with death, overall, or in subgroups.The severity of LV dilation at listing for heart transplant is associated with outcome in infants and young children with dilated cardiomyopathy, whereas the severity of LV systolic dysfunction is not. These findings should be considered in risk stratification of these children at listing.

  View details for DOI 10.1161/CIRCHEARTFAILURE.108.839001

  View details for Web of Science ID 000271893100010

  View details for PubMedID 19919984

• Hypercholesterolemia impairs exercise capacity in mice VASCULAR MEDICINE Maxwell, A. J., Niebauer, J., Lin, P. S., Tsao, P. S., Bernstein, D., Cooke, J. P. 2009; 14 (3): 249-257

  Abstract

  We previously reported an attenuation of both exercise hyperemia and measures of aerobic capacity in hypercholesterolemic mice. In this study, we expanded upon the previous findings by examining the temporal and quantitative relationship of hypercholesterolemia to aerobic and anaerobic capacity and by exploring several potential mechanisms of dysfunction. Eight-week-old wild type (n = 123) and apoE knockout (n = 79) C57BL/6J mice were divided into groups with distinct cholesterol levels by feeding with regular or high-fat diets. At various ages, the mice underwent treadmill ergospirometry. To explore mechanisms, aortic ring vasodilator function and nitrate (NO(x)) activity, urinary excretion of NO(x), running muscle microvascular density and citrate synthase activity, as well as myocardial mass and histologic evidence of ischemia were measured. At 8 weeks of age, all mice had similar measures of exercise capacity. All indices of aerobic exercise capacity progressively declined at 12 and 20 weeks of age in the hypercholesterolemic mice as cholesterol levels increased while indices of anaerobic capacity remained unaffected. Across the four cholesterol groups, the degree of aerobic dysfunction was related to serum cholesterol levels; a relationship that was maintained after correcting for confounding factors. Associated with the deterioration in exercise capacity was a decline in measures of nitric oxide-mediated vascular function while there was no evidence of aberrations in functional or oxidative capacities or in other components of transport capacity. In conclusion, aerobic exercise dysfunction is observed in murine models of genetic and diet-induced hypercholesterolemia and is associated with a reduction in vascular nitric oxide production.

  View details for DOI 10.1177/1358863X08100040

  View details for Web of Science ID 000268568300008

  View details for PubMedID 19651675

  View details for PubMedCentralID PMC3140166

• THE RESUSCITATED DECEASED DONOR HEART IS FUNCTIONALLY SUPERIOR TO THE BRAINSTEM DEAD DONOR HEART Ali, A. A., Fajardo, G., Tsuda, S., Budas, G., Ali, Z., Quertermous, T., Bernstein, D., Tsui, S., Robbins, R., Fischbein, M., Large, S., Ashley, E. WILEY-BLACKWELL PUBLISHING, INC. 2009: 138

  View details for Web of Science ID 000269392800514

• The impact of HLA-G polymorphism on acute rejection in pediatric heart transplant recipients Zeevi, A., Girnita, D. M., Brooks, M. M., Ferrell, R., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D., Webber, S. WILEY-BLACKWELL PUBLISHING, INC. 2009: 90

  View details for Web of Science ID 000266876500032

• Genotypic Variation and Phenotypic Characterization of Granzyme B Gene Polymorphisms TRANSPLANTATION Girnita, D. M., Webber, S. A., Brooks, M. M., Ferrell, R., Girnita, A. L., Burckart, G. J., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D., Zeevi, A. 2009; 87 (12): 1801-1806

  Abstract

  Granzyme B has been associated with allograft rejection in solid organ transplantation. Single nucleotide polymorphisms (SNPs) in the granzyme B gene might impact its expression. The aims of this study were (1) to establish the frequency of two granzyme B SNPs (A-295G; Q-55R) in pediatric heart transplant (PHTx) recipients and (2) to determine their phenotypic expression in healthy individuals.Three hundred ninety-six PHTx patients (245 white non-Hispanic, 49 black non-Hispanic, 82 Hispanics, and 20 others) and 52 healthy controls were screened for Q-55R and A-295G. For the control samples, we assessed the frequency of granzyme B positive cells by ELISPOT assay after mitogen stimulation.Among the PHTx recipients, 57% percent of the population carried the Q/Q genotype, whereas 6% were R/R homozygotes. Seven of 49 (14%) black non-Hispanics were R/R homozygotes, whereas 13 of 245 (5%) of white non-Hispanics and 5 of 82 (6%) Hispanics carried the R/R genotype (P=0.02). The A allele frequency of granzyme B A-295G (49.6%) was similar to that of the G allele (50.4%). However, 80% of Black non-Hispanics were A allele carriers compared with 68% of White non-Hispanics (P<0.0001). After mitogen stimulation, the frequency of granzyme B positive cells was higher in the Q/Q homozygotes compared with R/R carriers (P=0.006), whereas a similar frequency of granzyme B positive cells was noticed among the genotypes of A-295G SNP.These data indicate that 55 Q/Q genotype is associated with increased in vitro expression of granzyme B.

  View details for DOI 10.1097/TP.0b013e3181a755a4

  View details for Web of Science ID 000267361000007

  View details for PubMedID 19543056

  View details for PubMedCentralID PMC2739874

• Use of INTERMACS Criteria To Assess Major Clinical Outcomes In Children Bridged to Heart Transplant Using Mechanical Circulatory Support 29th Annual Meeting and Scientific Session of the International-Society-for-Heart-and-Lung-Transplantation Stein, M. L., Robbins, R., Sabati, A., Reinhartz, O., Chin, C., Liu, E., Bernstein, D., Roth, S., Wright, G., Reitz, B. ELSEVIER SCIENCE INC. 2009: S207–S208

  View details for Web of Science ID 000263539800406

• The Resuscitated DCD Donor Heart Is Functionally Superior to the Brainstem Dead Donor Heart Ali, A., Fajardo, G., Budas, G., Tsuda, S., Ali, Z., Quertermous, T., Bernstein, D., Tsui, S., Robbins, R., Fischbein, M., Large, S., Ashley, E. ELSEVIER SCIENCE INC. 2009: S71–S72

  View details for DOI 10.1016/j.healun.2008.11.026

  View details for Web of Science ID 000263539800021

• Genetic Polymorphisms Impact the Risk of Infection in Pediatric Heart Transplantation - A Multi-center Study Girnita, D. M., Brooks, M. M., Webber, S. A., Burckart, G. J., Ferrell, R., Girnita, A. L., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D., Zeevi, A. ELSEVIER SCIENCE INC. 2009: S251

  View details for DOI 10.1016/j.healun.2008.11.539

  View details for Web of Science ID 000263539800528

• C1q and Desensitization with IVIG: Use of a Novel HLA Complement Fixing Antibody Detection Technique To Guide Desensitization Therapy for Pediatric Heart Transplantation. Chin, C., Chen, G., Vayntrub, T., Siehr, S., Rosenthal, D., Reinhartz, O., Bernstein, D., Tyan, D. WILEY-BLACKWELL PUBLISHING, INC. 2009: 653

  View details for Web of Science ID 000265068801682

• Bacterial and Viral Infections Are Impacted by Different Genetic Polymorphisms - A Multicenter Pediatric Heart Transplant Study. Girnita, D. M., Brooks, M., Webber, S., Burckart, G., Ferrell, R., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J., Naftel, D., Girnita, A. L., Zeevi, A. WILEY-BLACKWELL PUBLISHING, INC. 2009: 196

  View details for Web of Science ID 000265068800020

• Sustained Pharmacological beta IIPKC Inhibition Is Cardioprotective In Late-stage Hypertrophy And End-stage Heart Failure In Two Rat Models 81st Annual Scientific Session of the American-Heart-Association Ferreira, J. C., Koyanagi, T., Inagaki, K., Fajardo, G., Churchill, E. N., Budas, G., Disatnik, M., Tsutsui, J. M., Kihara, Y., Bernstein, D., Brum, P. C., Mochly-Rosen, D. LIPPINCOTT WILLIAMS & WILKINS. 2008: S535–S535

  View details for Web of Science ID 000262104501368

• beta 2-Adrenergic Receptor Signaling Positively Modulates Pro-Survival Kinases and Ameliorates Mitochondrial Dysfunction during Doxorubicin Cardiotoxicity 81st Annual Scientific Session of the American-Heart-Association Fajardo, G., Zhao, M., Barry, G., Mochly-Rosen, D., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2008: S485–S486

  View details for Web of Science ID 000262104501157

• Molecular and physiological characterization of RV remodeling in a murine model of pulmonary stenosis AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Urashima, T., Zhao, M., Wagner, R., Fajardo, G., Farahani, S., Quertermous, T., Bernstein, D. 2008; 295 (3): H1351-H1368

  Abstract

  Right ventricular (RV) dysfunction is a common long-term complication in patients after the repair of congenital heart disease. Previous investigators have examined the cellular and molecular mechanisms of left ventricular (LV) remodeling, but little is known about the stressed RV. Our purpose was to provide a detailed physiological characterization of a model of RV hypertrophy and failure, including RV-LV interaction, and to compare gene alterations between afterloaded RV versus LV. Pulmonary artery constriction was performed in 86 mice. Mice with mild and moderate pulmonary stenosis (PS) developed stable hypertrophy without decompensation. Mice with severe PS developed edema, decreased RV function, and high mortality. Tissue Doppler imaging demonstrated septal dyssynchrony and deleterious RV-LV interaction in the severe PS group. Microarray analysis showed 196 genes with increased expression and 1,114 with decreased expression. Several transcripts were differentially increased in the afterloaded RV but not in the afterloaded LV, including clusterin, neuroblastoma suppression of tumorigenicity 1, Dkk3, Sfrp2, formin binding protein, annexin A7, and lysyl oxidase. We have characterized a murine model of RV hypertrophy and failure, providing a platform for studying the physiological and molecular events of RV remodeling. Although the molecular responses of the RV and LV to afterload stress are mostly concordant, there are several key differences, which may represent targets for RV failure-specific therapy.

  View details for DOI 10.1152/ajpheart.91526.2007

  View details for Web of Science ID 000258949200055

  View details for PubMedID 18586894

  View details for PubMedCentralID PMC2544484

• Effect of recipient genetic polymorphisms on pediatric heart allograft rejection: a multi-institutional study Girnita, D., Brooks, M., Webber, S., Burckart, G., Ferrell, R., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J., Naftel, D., Girnita, A., Zeevi, A. WILEY-BLACKWELL. 2008: 290

  View details for Web of Science ID 000258444500158

• Evaluation of Polymorphisms in Candidate Genes in the Dramatic Response to Pharmacologic Therapy of Heart Failure Basic Cardiovascular Sciences Conference Wheeler, M. T., Pavlovic, A., Dewey, F., Perez, M., Absher, D., Ho, M. Y., Cretti, E., Southwick, A., Rosenthal, D. N., Bernstein, D., Myers, R. M., Heidenreich, P. A., Fowler, M. B., Robbins, R. C., Ashley, E. A. LIPPINCOTT WILLIAMS & WILKINS. 2008: E64–E65

  View details for Web of Science ID 000258845200165

• The Apelin-APJ Pathway Is an Endogenous Regulator of Cardiac Function Ho, M. Y., Fajardo, G., Bollensdorff, C., Anderson, J., Charo, D., Chun, H., Kundu, R., Kohl, P., Bernstein, D., Quertermous, T., Ashley, E. LIPPINCOTT WILLIAMS & WILKINS. 2008: E52

  View details for Web of Science ID 000258845200099

• Overrepresentation of neuronal development pathways in heart failure patients who dramatically responded to pharmaceutical therapy 12th Annual Scientific Meeting of the Heart-Failure-Society-of-America Pavlovic, A., Perez, M., Absher, D., Wheeler, M., Ho, M., Dewey, R., Cretti, L., Southwick, A., Rosenthal, D., Bernstein, D., Myers, R. M., Heidenreich, P., Fowler, M. B., Robbins, R., Ashley, E. CHURCHILL LIVINGSTONE INC MEDICAL PUBLISHERS. 2008: S41–S41

  View details for Web of Science ID 000258565100129

• Genetic polymorphisms impact the risk of acute rejection in pediatric heart transplantation: A multi-institutional study TRANSPLANTATION Girnita, D. M., Brooks, M. M., Webber, S. A., Burckart, G. J., Ferrell, R., Zdanowicz, G., DeCroo, S., Smith, L., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Ranganathan, S., Naftel, D., Girnita, A. L., Zeevi, A. 2008; 85 (11): 1632-1639

  Abstract

  The objective of this study was to determine the association between the genetic polymorphisms of proinflammatory and regulatory cytokines and long-term rates of repeat and late acute rejection episodes in pediatric heart transplant (PHTx) recipients.Three hundred twenty-three PHTx recipients: 205 White non-Hispanic, 43 Black non-Hispanic, and 75 Hispanic were analyzed for time to first repeat and late acute rejection episodes by race, age at transplantation, and gene polymorphism (interleukin [IL]-6, -174 G/C, IL-10, -1082 G/A, -819 C/T, 592 C/A; vascular endothelial growth factor (VEGF) -2578 C/A, -460 C/T, +405 C/G; tumor necrosis factor alpha (TNF-alpha)-308 G/A).Recipient black race and older age at transplant were risk factors for both repeat and late rejections, though black race was more significantly related to late rejection (P=0.006). Individually, TNF-alpha high, IL-6 high, VEGF high, and IL-10 low phenotypes did not impact the risk of repeat or late rejection. However, the combination VEGF high/IL-6 high and IL-10 low was associated with increased estimated risk of late rejection (P=0.0004) and only marginally with repeat rejection (P=0.051). In a multivariate analysis, adjusting for age and race, VEGF high/IL-6 high and IL-10 low still remained an independent risk factor for late acute rejection (RR=1.91, P<0.001).This is the largest multicenter study to document the impact of genetic polymorphism combinations on PHTx recipients' outcome. The high proinflammatory (VEGF high/IL-6 high) and lower regulatory (IL-10 low) cytokine gene polymorphism profile exhibited increased risk for late rejection, irrespective of age and race/ethnicity.

  View details for DOI 10.1097/TP.0b013e3181722edc

  View details for Web of Science ID 000256712900018

  View details for PubMedID 18551071

• Prevention of pediatric graft coronary artery disease: Atorvastatin PEDIATRIC TRANSPLANTATION Chin, C., Lukito, S. S., Shek, J., Bernstein, D., Perry, S. B. 2008; 12 (4): 442-446

  Abstract

  Graft coronary artery disease is a significant cause of late graft failure and death after cardiac transplantation. HMG-coenzyme A reductase inhibitors have been used safely in children but their preventative effects against GCAD are not well known. We investigated whether atorvastatin when initiated early could prevent against the development of pediatric GCAD. Pediatric patients (transplanted between October 28, 1992 and July 9, 2004) were stratified into two groups based on whether or not they received atorvastatin early after transplant. Angiograms were reviewed by a single observer blinded to the treatment strategies and clinical outcomes. Actuarial survival method and the Mantel-Cox test were used to assess statistical significance. Freedom from GCAD was higher among those treated with atorvastatin early in the post-transplant course. One, three, and five-yr freedom from GCAD was significantly greater in the early treatment group (97%, 93%, and 93% respectively) compared with the control group (72%, 65%, and 60% respectively, p < 0.005). The early treatment group was also noted for fewer rejection episodes in the first post-transplant year. The use of atorvastatin when initiated early in the post-transplant course appears protective against graft coronary artery disease.

  View details for DOI 10.1111/j.1399-3046.2007.00827.x

  View details for PubMedID 18466431

• Effect of chronic ADMA administration on cardiac function in mice and on function of isolated cardiomyocytes in vitro Kielstein, J. T., Sheikh, A. Y., Fajardo, G., Bode-Boeger, S. M., Robbins, R. C., Bernstein, D., Haller, H., Cooke, J. R. LIPPINCOTT WILLIAMS & WILKINS. 2008: S370

  View details for Web of Science ID 000257197002455

• Microsystems for biomechanical measurements PEDIATRIC RESEARCH Norman, J. J., Mukundan, V., Bernstein, D., Pruitt, B. L. 2008; 63 (5): 576-583

  Abstract

  The use of microtechnology to make biomechanical measurements allows for the study of cellular and subcellular scale mechanical forces. Forces generated by cells are in the few nanoNewton to several microNewton range and can change spatially over subcellular size scales. Transducing forces at such small size and force scales is a challenging task. Methods of microfabrication developed in the integrated circuit industry have allowed researchers to build platforms with cellular and subcellular scale parts with which individual cells can interact. These parts act as transducers of stresses and forces generated by the cell during migration or in the maintenance of physical equilibrium. Due to the size and sensitivity of such devices, quantitative studies of single cell and even single molecule biomechanics have become possible. In this review we focus on two classes of cellular force transducers: silicon-based devices and soft-polymer platforms. We concentrate on the biomechanical discoveries made with these devices and less so on the engineering behind their development because this is covered in great detail elsewhere.

  View details for Web of Science ID 000255311900018

  View details for PubMedID 18427304

• Genetic Polymorphisms impact the risk of rejection with Hemodynamic compromise and chronic allograft vasculopathy - A multi-institutional study. Girnita, D. M., Brooks, M., Webber, S., Burckart, G., Ferrell, R., Zdanowicz, G., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J., Naftel, D., Girnita, A., Zeevi, A. WILEY-BLACKWELL. 2008: 225

  View details for Web of Science ID 000255763200174

• Genotypic variation and phenotypic characterization of granzyme B gene polymorphisms Girnita, D. M., Webber, S. A., Ferrell, R., Brooks, M. A., DeCroo, S., Burckart, G., Zdanowicz, G., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D., Smith, L., Girnita, A. L., Zeevi, A. ELSEVIER SCIENCE INC. 2008: S173–S174

  View details for DOI 10.1016/j.healun.2007.11.324

  View details for Web of Science ID 000253342300315

• Mechanical circulatory support in infants, children and adolescents as bridge to heart transplantation: Current outcomes Rosenthal, D. N., Pelletier, M., Wright, G., Reinhartz, O., Bernstein, D., Chin, C., Roth, S., Liu, E., Robbins, R., Reitz, B. ELSEVIER SCIENCE INC. 2008: S189

  View details for DOI 10.1016/j.healun.2007.11.366

  View details for Web of Science ID 000253342300356

• Association of left ventricular dilation at listing for heart transplant with post-listing and early post-iransplant survival in pediatric dilated cardiomyopathy Singh, T. P., Sleeper, L. A., Lipshultz, S., Cinar, A., Canter, C., Webber, S. A., Bernstein, D., Pahl, E., Alvarez, J., Towbin, J. A., Colan, S. A. ELSEVIER SCIENCE INC. 2008: S255

  View details for DOI 10.1016/j.healun.2007.11.555

  View details for Web of Science ID 000253342300541

• IMPACT OF GENETIC POLYMORPHISMS ON REJECTION WITH HEMODYNAMIC COMPROMISE - A MULTI-INSTITUTIONAL STUDY Girnita, D. M., Webber, S. A., Brooks, M. M., Burckart, G. J., Ferrell, R., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Naftel, D., Girnita, A. L., Zeevi, A. ELSEVIER SCIENCE INC. 2008: S111

  View details for DOI 10.1016/j.humimm.2008.08.232

  View details for Web of Science ID 000260373800214

• Gene expression profiling distinguishes a molecular signature for grade 1B mild acute cellular rejection in cardiac allograft recipients JOURNAL OF HEART AND LUNG TRANSPLANTATION Bernstein, D., Williams, G. E., Eisen, H., Mital, S., Wohlgemuth, J. G., Klingler, T. M., Fang, K. C., Deng, M. C., Kobashigawa, J. 2007; 26 (12): 1270-1280

  Abstract

  Gene expression profiling distinguishes the absence or presence of moderate to severe grades of acute cellular rejection in cardiac allograft recipients using a 20-gene classifier. We explored the hypothesis that the rejection classifier also differentiates various forms of mild rejection and we performed sub-analyses based on time post-transplant and confirmatory pathology interpretations.A post hoc analysis of 265 CARGO study patients and 714 clinical encounters focused on the correlation of rejection classifier-derived gene expression (GE) scores for blood samples accompanying endomyocardial biopsies. Biopsy grades assigned by a study center pathologist (center) were re-interpreted by three pathologists (panel) in a blinded manner.Mean GE scores not only differentiated Grades >or=3A from Grade 0 (p < 0.00001, center or panel), but also from Grades 1A or 2 (p < 0.05, center or panel), based on mild rejection sub-groups defined by the ISHLT 1990 grading system. In contrast, mean GE scores for Grades 1B and >or=3A were indistinguishable, using either center or panel interpretation. Sub-group analyses of encounters from 2 to 6 months or >6 months post-transplant showed similar results for the classifier's ability to discriminate moderate to severe rejection from Grades 1A and 2 mild rejection, but indistinguishable mean GE scores for Grades >or=3A and the Grade 1B sub-group. Of the classifier's 11 informative genes, expression of MIR and WDR40 showed statistically significant increases for both Grade 1B and Grade >or=3A rejection, while expression of PDCD1 or SEMA7A showed similar directional patterns without achieving statistical significance.These data demonstrate that GE scores discriminate moderate to severe rejection from Grades 1A and 2 mild rejection. However, a sub-group of mild rejection cases, defined as Grade 1B according to the 1990 grading system, share a molecular signature more consistent with moderate to severe rejection. The clinical relevance of these data remains to be defined.

  View details for DOI 10.1016/j.healun.2007.09.017

  View details for Web of Science ID 000251993500007

  View details for PubMedID 18096478

• Molecular and physiologic characterization of RV remodeling and failure in a murine model of mild, moderate and severe pulmonary stenosis 80th Annual Scientific Session of the American-Heart-Association (AHA) Urashima, T., Zhao, M., Wagner, R., Fajardo, G., Farahani, S., Quertermous, T., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2007: 702–

  View details for Web of Science ID 000250394303226

• Both beta-1 and beta-2 adrenergic receptors (ARs) are required for pressure overload cardiac hypertrophy 80th Annual Scientific Session of the American-Heart-Association (AHA) Zhao, M., Wagner, R., Fajardo, G., Urashima, T., Farahani, S., Kobilka, B. K., Quertermous, T., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2007: 50–51

  View details for Web of Science ID 000250394300224

• Both beta-1 and beta-2-adrenergic receptors (ARs) are required for pressure overload cardiac hypertrophy 4th Annual Symposium of the American-Heart-Association-Council on Basic Cardiovascular Sciences Zhao, M., Wagner, R., Fajardo, G., Urashima, T., Farahani, S., Kobilka, B., Quertermous, T., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2007: E76–E76

  View details for Web of Science ID 000249155000130

• Indications for heart transplantation in pediatric heart disease - A scientific statement from the American Heart Association Council on Cardiovascular Disease in the Young; the Councils on Clinical Cardiology, Cardiovascular Nursing, and Cardiovascular Surgery and Anesthesia; and the Quality of Care and Outcomes Research Interdisciplinary Working Group CIRCULATION Canter, C. E., Shaddy, R. E., Bernstein, D., Hsu, D. T., Chrisant, M. R., Kirklin, J. K., Kanter, K. R., Higgins, R. S., Blume, E. D., Rosenthal, D. N., Boucek, M. M., Uzark, K. C., Friedman, A. H., Young, J. K. 2007; 115 (5): 658-676

  Abstract

  Since the initial utilization of heart transplantation as therapy for end-stage pediatric heart disease, improvements have occurred in outcomes with heart transplantation and surgical therapies for congenital heart disease along with the application of medical therapies to pediatric heart failure that have improved outcomes in adults. These events justify a reevaluation of the indications for heart transplantation in congenital heart disease and other causes of pediatric heart failure.A working group was commissioned to review accumulated experience with pediatric heart transplantation and its use in patients with unrepaired and/or previously repaired or palliated congenital heart disease (children and adults), in patients with pediatric cardiomyopathies, and in pediatric patients with prior heart transplantation. Evidence-based guidelines for the indications for heart transplantation or retransplantation for these conditions were developed.This evaluation has led to the development and refinement of indications for heart transplantation for patients with congenital heart disease and pediatric cardiomyopathies in addition to indications for pediatric heart retransplantation.

  View details for DOI 10.1161/CIRCULATIONAHA.106.180449

  View details for Web of Science ID 000244000800018

  View details for PubMedID 17261651

• Gene expression profiling distinguishes moderate to severe from mild acute cellular rejection in cardiac allograft recipients Bernstein, D., Berry, G., Billingham, M., Marboe, C. C., Deng, M. C., Mital, S., Eisen, H., Williams, G. E., Baron, H., Klingler, T. M., Wohlgemuth, J. G., Kobashigawa, J. ELSEVIER SCIENCE INC. 2007: S121–S121

  View details for Web of Science ID 000244342200171

• Disparate distribution of 16 candidate single nucleotide polymorphisms among racial and ethnic groups of pediatric heart transplant patients TRANSPLANTATION Girnita, D. M., Webber, S. A., Ferrell, R., Burckart, G. J., Brooks, M. M., McDade, K. K., Chinnock, R., Canter, C., Addonizio, L., Bernstein, D., Kirklin, J. K., Girnita, A. L., Zeevi, A. 2006; 82 (12): 1774-1780

  Abstract

  Allograft failure in African-Americans remains higher than in Caucasians. Single nucleotide polymorphisms (SNPs) have been associated with altered allograft outcomes.In this multi-center study we compared SNP frequencies in 364 pediatric heart recipients from three ethnic/racial groups: Caucasian (n = 243), African-American (n = 39), and Hispanic (n = 82). The target genes were: tumor necrosis factor-alpha, interleukin (IL)-10, IL-6, interferon (IFN)-gamma, vascular endothelial growth factor (VEGF), transforming growth factor-beta1, Fas, FasL, granzyme B, ABCB1, CYP3A5.Compared to Caucasians, African-Americans exhibited a higher prevalence of genotypes associated with low expression of IFN-gamma (24% vs. 45.7%, P < 0.001) and IL-10 (33% vs. 57.1%, P = 0.052). African-Americans also exhibited an increased prevalence of high IL-6 (82.9% vs. 38.1%; P < 0.001). VEGF -2578 C/C and -460 C/C genotypes were found more frequently in African-Americans and Hispanics as compared to Caucasians (P < 0.001). G/G genotype of Fas and T/T genotype of FasL were expressed more often by African-American recipients. The prevalence of Granzyme B (-295A/G) genotype was differentially distributed in the three groups. Compared with Caucasians, African-Americans were twice as likely to carry the ABCB1 2677 G/G genotype (78.6% vs. 33.7%, P < 0.0025), and they were more frequent carriers of the CYP3A5 *1/*1 genotype (35.7% vs. 0.6% in Caucasians and 7.2% in Hispanics; P < 0.001).African-Americans have a genetic background that may predispose to proinflammatory/lower regulatory environment, reduced drug exposure and immunosuppressive efficacy. In this ongoing multicenter study, these gene polymorphisms differences among ethnic/racial groups are being documented so that therapeutic strategies can be devised to optimize outcomes for pediatric transplant recipients.

  View details for DOI 10.1097/01.tp.0000250656.33731.08

  View details for Web of Science ID 000243178200046

  View details for PubMedID 17198275

• Apelin regulates cardiac contractility and rescues neurohormonal heart failure 79th Annual Scientific Session of the American-Heart-Association Ernst, K. V., Ashley, E. A., Charo, D., Kawana, M., Fajardo, G., Bernstein, D., Quertermous, T. LIPPINCOTT WILLIAMS & WILKINS. 2006: 66–66

  View details for Web of Science ID 000241792800321

• Apelin regulates cardiac contractility and rescues neurohormonal heart failure 10th Annual Scientific Meeting of the Heart-Failure-Society-of-America Ernst, K. V., Ashley, E. A., Charo, D., Kawana, M., Fajardo, G., Bernstein, D., Quertermous, T. CHURCHILL LIVINGSTONE INC MEDICAL PUBLISHERS. 2006: S1–S1

  View details for Web of Science ID 000240205000003

• Pediatric cardiac transplantation. Seminars in pediatric surgery Alkhaldi, A., Chin, C., Bernstein, D. 2006; 15 (3): 188-198

  Abstract

  Pediatric heart transplantation has undergone major changes over the past two decades, marked by a substantial improvement in survival, reduction in posttransplant complications, and enhancement in quality of life for transplant recipients. Actuarial survival has improved substantially in the last decade. Indications for pediatric heart transplant have changed as surgery for complex congenital heart lesions has evolved. There are now left and right ventricular assist devices that are suitable for use in infants as a bridge to transplantation. New immunosuppressive agents have reduced the risk of rejection while minimizing side effects and strategies to reduce the risk of graft coronary disease are beginning to show promise. Finally, true long-term survival for children after heart transplant has now been demonstrated and quality of life is excellent.

  View details for PubMedID 16818140

• Biological effects of the novel peptide apelin are uniquely suited to the treatment of acute heart failure 28th Congress of the European-Society-of-Cardiology/World Congress of Cardiology Ashley, E., Charo, D., Ernst, K., Chen, M., Fajardo, G., Kawana, M., Bernstein, D., Quertermous, T. OXFORD UNIV PRESS. 2006: 854–854

  View details for Web of Science ID 000240668406103

• Outcome of listing for cardiac transplantation for failed Fontan - A multi-institutional study CIRCULATION Bernstein, D., Naftel, D., Chin, C., Addonizio, L. J., Gamberg, P., Blume, E. D., Hsu, D., Canter, C. E., Kirklin, J. K., Morrow, W. R. 2006; 114 (4): 273-280

  Abstract

  The Fontan procedure is a successful palliation for children with single-ventricle physiology; however, many will eventually require heart transplantation. The purpose of this study was to determine risk factors for death awaiting transplantation and to examine results after transplantation in Fontan patients.A retrospective, multi-institutional review was performed of 97 Fontan patients <18 years of age listed at 17 Pediatric Heart Transplant Study centers from 1993 to 2001. Mean age at listing was 9.7 years (0.5 to 17.9 years); 25% were <4 years old; 53% were United Network for Organ Sharing status 1; 18% required ventilator support. Pretransplantation survival was 78% at 6 months and 74% at 12 months and was similar to 243 children with other congenital heart disease (CHD) and 747 children without congenital heart disease (No-CHD), who were also awaiting transplantation. Patients who were younger, status 1, had shorter interval since Fontan, or were on a ventilator were more likely to die while waiting. At 6 months, the probability of receiving a transplant was similar for status 1 and 2 (65% versus 68%); however, the probability of death was higher for status 1 (22% versus 5%). Seventy patients underwent transplantation. Survival was 76% at 1 year, 70% at 3 years, and 68% at 5 years, slightly less than CHD and No-CHD patients. Causes of death included infection (30%), graft failure (17%), rejection (13%), sudden death (13%), and graft coronary artery disease (9%). Protein-losing enteropathy (present in 34 patients) resolved in all who survived >30 days after transplantation.Heart transplantation is an effective therapy for pediatric patients with a failed Fontan. Although early posttransplantation survival is slightly lower than other patients with CHD, long-term results are encouraging, and protein-losing enteropathy can be expected to resolve.

  View details for DOI 10.1161/CIRCULATIONAHA.105.548016

  View details for Web of Science ID 000239237200007

  View details for PubMedID 16847155

• Neurologic events in neonates treated surgically for congenital heart disease JOURNAL OF PERINATOLOGY Chock, V. Y., Reddy, V. M., Bernstein, D., Madan, A. 2006; 26 (4): 237-242

  Abstract

  The incidence of acute neurologic events prior to discharge in neonates with congenital heart disease (CHD) was determined and peri-operative characteristics predictive of a neurologic event were identified.A retrospective chart review over 1 year was conducted of infants <1 month of age with a diagnosis of CHD. Outcomes were measured by the occurrence of an acute neurologic event defined as electroencephalogram (EEG)-proven seizure activity, significant hypertonia or hypotonia, or choreoathetosis prior to hospital discharge. Stepwise logistic regression identified variables most likely to be associated with an acute neurologic event.Surgical intervention occurred in 95 infants who were admitted with a diagnosis of CHD. The survival rate was 92%. Of the survivors, 16 (17%) had an acute neurologic event, with 19% of events occurring preoperatively. Factors associated with neurologic events included an elevated nucleated red blood cell (NRBC) count, an abnormal preoperative brain imaging study, and a 5-min Apgar score <7 (P<0.05).Neonates with CHD have a significant risk of neurologic events. Preoperative brain imaging, the 5-min Apgar score, and initial serum NRBC counts may identify infants at highest risk for central nervous system injury.

  View details for DOI 10.1038/sj.jp.7211459

  View details for Web of Science ID 000241843200006

  View details for PubMedID 16496014

• Differential cardiotoxic/cardioprotective effects of beta-adrenergic receptor subtypes in myocytes and fibroblasts in doxorubicin cardiomyopathy JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY Fajardo, G., Zhao, M. M., Powers, J., Bernstein, D. 2006; 40 (3): 375-383

  Abstract

  beta-Adrenoceptor (beta-AR) subtypes act through different signaling pathways to regulate cardiac function and remodeling. Previous in vivo data show a markedly enhanced cardiotoxic response to doxorubicin in beta2-/- mice, which is rescued by the additional deletion of the beta1-AR. We determined whether this differential response was myocyte specific by examining the effects of doxorubicin in myocytes and fibroblasts from WT and beta1, beta2 and beta1/beta2-/- mice. Cells were exposed to doxorubicin at 1-50 microM and viability and apoptosis assessed at 6, 24 and 48 h. WT myocytes showed a time and dose-dependent decrease in viability (42% decrease at 1 microM after 24 h). beta2-/- Myocytes showed a greater decrease in viability vs. WT (20.8% less at 6 h; 14% less at 24 h, P<0.05); beta1-/- and beta1/beta2-/- myocytes showed enhanced survival (beta1-/- 11%; beta1/beta2-/- 18% greater than WT, P<0.05). TUNEL staining demonstrated a similar differential susceptibility (WT 26% apoptotic nuclei, beta2-/- 45.9%, beta1/beta2-/- 16.8%, P<0.05). beta2-/- Fibroblasts also showed enhanced toxicity. Pertussis toxin pretreatment of WT cells decreased survival similar to the beta2-/-, suggesting a role for Gi signaling. JNK was differentially activated in beta2-/- myocytes after doxorubicin and its inhibition increased cardiotoxicity. In conclusion, the differential cardioprotective/cardiotoxic effects mediated by beta1 vs. beta2-AR subtypes in knockout mice are recapitulated in myocytes isolated from these mice. beta2-ARs appear to play a cardioprotective role, whereas beta1-ARs a cardiotoxic role.

  View details for DOI 10.1016/j.yjmcc.2005.12.004

  View details for Web of Science ID 000236059300006

  View details for PubMedID 16458323

  View details for PubMedCentralID PMC3140223

• Ten- and 20-year survivors of pediatric orthotopic heart transplantation JOURNAL OF HEART AND LUNG TRANSPLANTATION Ross, M., Kouretas, P., Gamberg, P., Miller, J., Burge, M., Reitz, B., Robbins, R., Chin, C., Bernstein, D. 2006; 25 (3): 261-270

  Abstract

  Pediatric heart transplantation is entering its third decade, allowing for the first time an analysis of a large group of true long-term survivors, specifically children who have survived > or =10 years post-transplantation.Fifty-two patients < or =18 years, who had undergone heart transplantation at Stanford between August 1974 and June 1993 and survived > or =10 years, were retrospectively reviewed.Forty (77%) patients are currently alive. Thirteen survived >15 years and 5 >20 years (the longest being 26 years). Actuarial survival was 79.4% at 14 years and 53.1% at 20 years. Cardiomyopathy was the reason for transplantation in 71% and congenital heart disease (CHD) in 29%. At last evaluation, 71% were on a cyclosporine-based regimen and 23% a tacrolimus-based regimen; 33% were steroid-free. Twenty-seven percent were totally free from treatable rejection, 44% developed serious infections, 69% were receiving anti-hypertensives, and 8% required renal transplantation. Neoplasms occurred in 23%, graft coronary artery disease (CAD) in 31%, and 15% required re-transplantation. Of the 12 deaths, CAD was the most common cause (n = 4), followed by non-specific late graft failure (n = 3), infection (n = 2), rejection (n = 1), non-lymphoid cancer (n = 1) and lymphoid cancer (n = 1). Physical rehabilitation and return to normal lifestyle has been nearly 100%.Heart transplantation in pediatric patients is compatible with true long-term survival with a growing cohort of children approaching their second and third decades. The gradual constant-phase decrease in survival noted in earlier studies appears to be continuing. Rejection and infection are low but persistent risks after the first years. Graft CAD and non-specific late graft dysfunction are the leading causes of death after 10 years. Rehabilitation is excellent.

  View details for DOI 10.1016/j.healun.2005.09.011

  View details for PubMedID 16507417

• Prevention of pediatric graft coronary artery disease: Atorvastatin Chin, C., Bernstein, D., SHEK, J., Gamberg, P., Perry, S. ELSEVIER SCIENCE INC. 2006: S183–S184

  View details for Web of Science ID 000203407400406

• Effect of targeted deletions of beta(1)- and beta(2)-adrenergic-receptor subtypes on heart rate variability AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Ecker, P. M., Lin, C. C., Powers, J., Kobilka, B. K., Dubin, A. M., Bernstein, D. 2006; 290 (1): H192-H199

  Abstract

  Beta-adrenergic receptors (beta-ARs) play a major role in regulating heart rate (HR) and contractility in the intact cardiovascular system. Three subtypes (beta1, beta2, and beta3) are expressed in heart tissue, and the role of each subtype in regulating cardiac function has previously been determined by using both pharmacological and gene-targeting approaches. However, previous studies have only examined the role of beta-ARs in the macrolevel regulation of HR. We employed three knockout (KO) mouse lines, beta1-KO, beta2-KO, and beta1/beta2 double KO (DL-KO), to examine the role that beta-AR subtypes play in HR variability (HRV) and in the sympathetic and parasympathetic inputs into HR control. Fast Fourier transformation (FFT) in frequency domain methods of ECG spectral analysis was used to resolve HRV into high- and low-frequency (HF and LF) powers. Resting HR (in beats/min) was decreased in beta1-KO [488 (SD 27)] and DL-KO [495 (SD 12)] mice compared with wild-type [WT; 638 (SD 30)] or beta2-KO [656 (SD 51)] (P < 0.0005) mice. Mice lacking beta1-ARs (beta1-KO and DL-KO) had increased HRV (as illustrated by the standard deviation of normal R-R intervals) and increased normalized HF and LF powers compared with mice with intact beta1-ARs (WT and beta2-KO). These results demonstrate the differential role of beta-AR subtypes in regulating autonomic signaling.

  View details for DOI 10.1152/ajpheart.00032.2005

  View details for Web of Science ID 000234148200023

  View details for PubMedID 16113068

• Differential cardioprotective/cardiotoxic effects mediated by ss-adrenergic receptor subtypes AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Bernstein, D., Fajardo, G., Zhao, M. M., Urashima, T., Powers, J., Berry, G., Kobilka, B. K. 2005; 289 (6): H2441-H2449

  Abstract

  Recent data suggest that beta-adrenergic receptor subtypes couple differentially to signaling pathways regulating cardiac function vs. cardiac remodeling. To dissect the roles of beta1- vs. beta2-receptors in the pathogenesis of cardiomyopathy, doxorubicin was administered to beta1, beta2, and beta1/beta2 knockout (-/-) and wild-type mice. Expression and activation of MAPKs were measured. Wild-type and beta1-/- mice showed no acute cardiovascular effects, whereas beta2-/- mice all died within 30 min. The additional deletion of the beta1-receptor (beta1/beta2-/-) totally rescued this toxicity. beta2-/- mice developed decreased contractile function, hypotension, QTc prolongation, and ST segment changes and a 20-fold increase in p38 MAPK activity not seen in the other genotypes. The MAPK inhibitor SB-203580 rescued beta2-/- mice from this acute toxicity. The enhanced toxicity in beta2-/- mice was also recapitulated in wild-type mice with the beta2-selective antagonist ICI-118,551, although the rescue effect of the beta1-deletion was not recapitulated using the beta1-selective antagonist metoprolol or the nonselective beta-antagonist propranolol. These data suggest that beta2-adrenergic receptors play a cardioprotective role in the pathogenesis of cardiomyopathy, whereas beta1-adrenergic receptors mediate at least some of the acute cardiotoxicity of anthracyclines. Differential activation of MAPK isoforms, previously shown in vitro to regulate beta-agonist as well as doxorubicin cardiotoxicity, appears to play a role in mediating the differential effects of these beta-adrenergic receptor subtypes in vivo.

  View details for DOI 10.1152/ajpheart.00005.2005

  View details for Web of Science ID 000233176600023

  View details for PubMedID 16040722

• Increased fibulin-5 and elastin in S100A4/Mts1 mice with pulmonary hypertension CIRCULATION RESEARCH Merklinger, S. L., Wagner, R. A., Spiekerkoetter, E., Hinek, A., Knutsen, R. H., Kabir, M. G., Desai, K., Hacker, S., Wang, L. L., Cann, G. M., Ambartsumian, N. S., Lukanidin, E., Bernstein, D., Husain, M., Mecham, R. P., Starcher, B., Yanagisawa, H., Rabinovitch, M. 2005; 97 (6): 596-604

  Abstract

  Transgenic mice overexpressing the calcium binding protein, S100A4/Mts1, occasionally develop severe pulmonary vascular obstructive disease. To understand what underlies this propensity, we compared the pulmonary vascular hemodynamic and structural features of S100A4/Mts1 with control C57Bl/6 mice at baseline, following a 2-week exposure to chronic hypoxia, and after 1 and 3 months "recovery" in room air. S100A4/Mts1 mice had greater right ventricular systolic pressure and right ventricular hypertrophy at baseline, which increased further with chronic hypoxia and was sustained after 3 months "recovery" in room air. These findings correlated with a heightened response to acute hypoxia and failure to vasodilate with nitric oxide or oxygen. S100A4/Mts1 mice, when compared with C57Bl/6 mice, also had impaired cardiac function judged by reduced ventricular elastance and decreased cardiac output. Despite higher right ventricular systolic pressures with chronic hypoxia, S100A4/Mts1 mice did not develop more severe PVD, but in contrast to C57Bl/6 mice, these features did not regress on return to room air. Microarray analysis of lung tissue identified a number of genes differentially upregulated in S100A4/Mts1 versus control mice. One of these, fibulin-5, is a matrix component necessary for normal elastin fiber assembly. Fibulin-5 was localized to pulmonary arteries and associated with thickened elastic laminae. This feature could underlie attenuation of pulmonary vascular changes in response to elevated pressure, as well as impaired reversibility.

  View details for DOI 10.1161/01.RES.00000182425.49768.8a

  View details for Web of Science ID 000231896500013

  View details for PubMedID 16109920

• Induction therapy for pediatric and adult heart transplantation: Comparison between OKT3 and daclizumab TRANSPLANTATION Chin, C., Pittson, S., Luikart, H., Bernstein, D., Robbins, R., Reitz, B., Oyer, P., Valantine, H. 2005; 80 (4): 477-481

  Abstract

  Induction therapy can reduce morbidity and early mortality in pediatric and adult heart transplant recipients. Monoclonal and polyclonal agents are most widely used; they nonspecifically deplete the T-cell pool and are thus associated with drug-induced side effects. The cytokine release syndrome is one of the most problematic events associated with induction. Daclizumab, a highly humanized, specific interleukin-2 receptor blocker, may be efficacious to the monoclonal agent, OKT3. Due to its specific action and properties, the safety profile of this agent may be superior to OKT3.Forty subjects received daclizumab and their clinical outcomes were compared against a historical group of 40 subjects who received OKT3. Three- and six-month outcome measures included survival, rejection history, steroid burden, and complications.Mortality was low between the groups with equivalent 6-month survival. No differences in rejection profile or time to the first significant rejection event were detected; no subject had severe acute rejection within the first 180 days. Steroid requirement for maintenance immunosuppression and treatment of rejection was also similar between the groups. Six-month prevalence for complications were significantly different; 55% of OKT3-treated subjects having at least one event compared to 33% of daclizumab-treated subjects (P=0.04). The likelihood of complications occurred within the first month after transplantation.Daclizumab induction therapy is as efficacious as OKT3 in the prevention of early acute rejection after heart transplantation among pediatric and adult subjects. Complications related to the induction agent are significantly lower in the humanized product.

  View details for DOI 10.1097/01.tp.0000168153.50774.30

  View details for Web of Science ID 000231566800008

  View details for PubMedID 16123721

• Experience of percutaneous coronary intervention in the management of pediatric cardiac allograft vasculopathy JOURNAL OF HEART AND LUNG TRANSPLANTATION Tham, E. B., Yeung, A. C., Cheng, C. W., Bernstein, D., Chin, C., Feinstein, J. A. 2005; 24 (6): 769-773

  Abstract

  In a retrospective study, we examined the procedural success rate and the short-, intermediate-, and long-term outcomes of coronary interventional procedures in children with cardiac allograft vasculopathy. Seven patients underwent 13 interventional procedures: balloon angioplasty alone (n = 3), angioplasty with stenting (n = 9), or angioplasty with brachytherapy (n = 1), with procedural success in all. Two major complications (cardiac arrest) and a single death occurred in the immediate postprocedural period. Five (83%) of the remaining 6 patients developed moderate to severe restenosis, diffuse disease, or progressive vasculopathy; 3 have been retransplanted, 1 died from progressive cardiac allograft vasculopathy, and 1 is awaiting retransplantation, 40 months after the procedure.

  View details for DOI 10.1016/j.healun.2004.04.009

  View details for PubMedID 15949739

• The role of beta-adrenergic receptor signaling in cardioprotection. FASEB journal Tong, H., Bernstein, D., Murphy, E., Steenbergen, C. 2005; 19 (8): 983-985

  Abstract

  This study examines the role of the beta2-adrenergic receptor (beta2-AR) in cardioprotection. The beta2-AR couples to Gs and Gi proteins. Gs activates PKA, which phosphorylates the receptor and switches beta2-AR coupling from Gs to Gi. Prior to 20 min of global ischemia, mouse hearts were either perfused for 30 min without treatment (control), treated with 10 nmol/L of isoproterenol (ISO) for 5 min followed by 5 min washout, or preconditioned with 4 cycles of 5 min ischemia and 5 min reflow (PC). Recovery of left ventricular developed pressure (LVDP) and infarct size were measured. Intermittent ISO treatment improved post-ischemic recovery of LVDP (58.5+/-4.8% vs. 22.0+/-6.3% in control) and reduced infarct size (31.0+/-2.4% vs. 53.0+/-4.6% in control). The Gi inhibitor pertussis toxin blocked the ISO-induced improvement in postischemic LVDP and infarct size. To test the role of beta2-AR in PC, we studied mice lacking beta2-AR (beta2-AR-/-) and found that PC had no effect on postischemic LVDP or infarct size in beta2-AR-/-. To test whether PKA is required for the PC and ISO-induced protection, hearts were treated with the PKA inhibitors PKI and H-89. We found that PKI and H-89 blocked the PC- and ISO-induced improvement in postischemic LVDP and infarct size. These data show an important role for beta2-AR in cardioprotection and support the novel hypothesis that preconditioning involves switching of beta2-AR coupling from Gs to Gi.

  View details for PubMedID 15802488

• The role of beta-adrenergic receptor signaling in cardioprotection FASEB JOURNAL Tong, H., Bernstein, D., Murphy, E., Steenbergen, C. 2005; 19 (3): 983-?

  View details for DOI 10.1096/fj.04-3067fje

  View details for Web of Science ID 000227901300041

• Gene expression profiling of cardiac allograft recipients with mild acute cellular rejection Bernstein, D., Mital, S., Addonizio, L., Hunt, S., Deng, M. C., Baron, H., Murali, S., Tayama, D. Y., Klingler, T. M., Wohlgemulh, J. G., Webber, S. ELSEVIER SCIENCE INC. 2005: S65–S65

  View details for Web of Science ID 000203407500073

• The endogenous peptide apelin potently improves cardiac contractility and reduces cardiac loading in vivo CARDIOVASCULAR RESEARCH Ashley, E. A., Powers, J., Chen, M., Kundu, R., Finsterbach, T., Caffarelli, A., Deng, A., Eichhorn, J., Mahajan, R., Agrawal, R., Greve, J., Robbins, R., Patterson, A. J., Bernstein, D., Quertermous, T. 2005; 65 (1): 73-82

  Abstract

  The endogenous peptide apelin is differentially regulated in cardiovascular disease but the nature of its role in cardiac function remains unclear.We investigated the functional relevance of this peptide using ECG and respiration gated magnetic resonance imaging, conductance catheter pressure-volume hemodynamic measurements, and echocardiography in vivo. In addition, we carried out histology and immunohistochemistry to assess cardiac hypertrophy and to localize apelin and APJ in the adult and embryonic mouse heart.Intraperitoneal injection of apelin (300 microg/kg) resulted in a decrease in left ventricular end diastolic area (pre: 0.122+/-0.007; post: 0.104+/-0.005 cm(2), p=0.006) and an increase in heart rate (pre: 537+/-20; post: 559+/-19 beats per minute, p=0.03). Hemodynamic measurements revealed a marked increase in ventricular elastance (pre: 3.7+/-0.9; post: 6.5+/-1.4 mm Hg/RVU, p=0.018) and preload recruitable stroke work (pre: 27.4+/-8.0; post: 51.8+/-3.1, p=0.059) with little change in diastolic parameters following acute infusion of apelin. Chronic infusion (2 mg/kg/day) resulted in significant increases in the velocity of circumferential shortening (baseline: 5.36+/-0.401; 14 days: 6.85+/-0.358 circ/s, p=0.049) and cardiac output (baseline: 0.142+/-0.019; 14 days: 0.25+/-0.019 l/min, p=0.001) as determined by 15 MHz echocardiography. Post-mortem corrected heart weights were not different between apelin and saline groups (p=0.5) and histology revealed no evidence of cellular hypertrophy in the apelin group (nuclei per unit area, p=0.9). Immunohistochemistry studies revealed APJ staining of myocardial cells in all regions of the adult mouse heart. Antibody staining, as well as quantitative real time polymerase chain reaction identified expression of both APJ and apelin in embryonic myocardium as early as embryonic day 13.5.Apelin reduces left ventricular preload and afterload and increases contractile reserve without evidence of hypertrophy. These results associate apelin with a positive hemodynamic profile and suggest it as an attractive target for pharmacotherapy in the setting of heart failure.

  View details for DOI 10.1016/j.cardiores.2004.08.018

  View details for Web of Science ID 000226477600011

  View details for PubMedID 15621035

  View details for PubMedCentralID PMC2517138

• Pharmacotherapy of hyperlipidemia in pediatric heart transplant recipients: current practice and future directions. Paediatric drugs Chin, C., Bernstein, D. 2005; 7 (6): 391-396

  Abstract

  Lipoprotein abnormalities are fairly common after pediatric heart transplantation. Graft coronary artery disease (GCAD) limits long-term survival and has been linked to elevated serum triglyceride levels and decreased high-density lipoprotein levels. Histologically, GCAD represents intimal hyperplasia of the coronary vessel and is best imaged by intravascular ultrasound.A number of pharmacologic agents are available for the management of lipid disorders but experience with these drugs has mainly been in adults. HMG-CoA reductase inhibitors (statins) are currently used by many adult transplantation centers to alter lipid profiles in the hope of reducing GCAD. The use of statins among pediatric heart transplant centers is more limited. Although rhabdomyolysis is a concern with these agents, the incidence among individuals receiving immunosuppressant therapy is low. Aside from their lipid-lowering properties, statins may also protect against graft failure and rejection.

  View details for PubMedID 16356026

• Genome-wide expression profiling of a cardiac pressure overload model identifies major metabolic and signaling pathway responses JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY Wagner, R. A., Tabibiazar, R., Powers, J., Bernstein, D., Quertermous, T. 2004; 37 (6): 1159-1170

  Abstract

  Cardiac hypertrophy is a predictor of cardiovascular morbidity and mortality independent of other risk factors. Pressure overload induces the development of left ventricular hypertrophy (LVH) and left atrial enlargement (LAE) in the mammalian heart. To systematically investigate the transcriptional changes, which mediate these processes, we have performed a genome-wide transcriptional profiling of each of the four heart chambers from mice subjected to transverse aortic constriction (TAC). A major new finding of this analysis is that during enlargement the left atrium undergoes radical changes in gene transcription that may play a significant role in pathophysiology. Structural changes in the LA and LV are correlated with significant changes in the transcriptional profile of these chambers, with thousands of differentially expressed known and novel factors. Statistical analysis of the results identified Gene Ontology biological process groups with significant group-wide changes, including angiogenesis, energy pathways, fatty acid oxidation, oxidative phosphorylation, cytoskeletal and matrix reorganization, and G-protein coupled receptor (GPCR) signaling. To facilitate future research, a searchable annotated Internet database has been constructed that allows access to the expression data presented here. Further study of these genes and processes will lead to better understanding of pathways involved in the pathophysiology of the cardiac response to pressure overload.

  View details for DOI 10.1016/j.yjmcc.2004.09.003

  View details for Web of Science ID 000225905300007

  View details for PubMedID 15572046

• International society for heart and lung transplantation: Practice guidelines for management of heart failure in children JOURNAL OF HEART AND LUNG TRANSPLANTATION Rosenthal, D., Chrisant, M. R., Edens, E., Mahony, L., Canter, C., Colan, S., Dubin, A., Lamour, J., Ross, R., Shaddy, R., Addonizio, L., Beerman, L., Berger, S., Bernstein, D., Blume, E., Boucek, M., Checchia, P., Dipchand, A., Drummond-Webb, J., Fricker, J., Friedman, R., Hallowell, S., Jaquiss, R., Mital, S., Pahl, E., Pearce, B., Rhodes, L., Rotondo, K., Rusconi, P., Scheel, J., Singh, T. P., Towbin, J. 2004; 23 (12): 1313-1333

  View details for Web of Science ID 000226087100001

  View details for PubMedID 15607659

• The mouse as a model of cardiovascular adaptations to microgravity JOURNAL OF APPLIED PHYSIOLOGY Powers, J., Bernstein, D. 2004; 97 (5): 1686-1692

  Abstract

  There are a multitude of physiological adaptations to microgravity, involving the cardiovascular, neuromuscular, and neuroendocrine systems. Some of these adaptations lead to cardiovascular deconditioning on return to normal gravity, posing a threat to human functional integrity after long-term spaceflight. Animal models of microgravity, e.g., tail suspension in rats, have yielded important information regarding the mechanism of these adaptations and have been useful in the design of countermeasures. The mouse could potentially be a useful experimental model, given its small size (smaller and lighter payload) and the powerful tools of experimental mouse genetics, which allow us to dissect mechanisms on a gene-specific basis. We show that the mouse demonstrates a wide range of cardiovascular responses to simulated microgravity, including alterations in heart rate, exercise capacity, peripheral arterial vasodilatory responsiveness, and baroreflex response. These responses are qualitatively similar to many of those demonstrated in humans during spaceflight and in rats using tail suspension, although there are some important differences. Thus the mouse has value as a model for studies of cardiovascular changes during microgravity; however, investigators must maintain an appreciation of important species differences.

  View details for DOI 10.1152/japplphysiol.00925.2003

  View details for Web of Science ID 000224361700020

  View details for PubMedID 15258130

• beta-adrenergic receptor (beta-AR) subtypes have opposing effects on survival and cardiac function in MLP cardiomyopathy 77th Scientific Meeting of the American-Heart-Association Zhao, M. M., Fajardo, G., Bernstein, D. LIPPINCOTT WILLIAMS & WILKINS. 2004: 197–97

  View details for Web of Science ID 000224783501098

• Microarray analysis of gene expression after transverse aortic constriction in mice PHYSIOLOGICAL GENOMICS Zhao, M. M., Chow, A., Powers, J., Fajardo, G., Bernstein, D. 2004; 19 (1): 93-105

  Abstract

  Cardiac hypertrophy is a compensatory response initially beneficial to heart function but can ultimately lead to cardiac decompensation. It is an integrated process involving multiple cellular signaling pathways and their cross talk. Microarray GeneChip technology is a powerful new tool to identify gene expression profiles of cardiac hypertrophy. To identify well-characterized as well as novel adaptive mechanisms, we utilized a murine model of compensated pressure overload hypertrophy (transverse aortic constriction, TAC). At 48 h, 10 days, and 3 wk, hearts were harvested and total RNA hybridized to Affymetrix U74Av2 GeneChips, which contain a 12,488-gene/EST probe set. Verification of gene expression was performed by SYBR quantitative real-time RT-PCR (QRT-PCR) for selected genes. A rigorous evaluation of the adequacy of the control condition was also performed. For statistical analysis we generated a four-step filtering criteria. Our results show an upregulation of 38 genes (48 h), 269 genes (10 days), and 203 genes (3 wk) and downregulation of 15 genes (48 h), 160 genes (10 days), and 124 genes (3 wk). Transcripts differentially expressed after TAC were categorized into 12 functional groups and revealed the presence of several intriguing transcripts, e.g., cell proliferation-related Ki-67 and several apoptosis-related genes. Overall changes in QRT-PCR were in accordance with GeneChip data, with the highest correlation for genes with the largest up- or downregulation with TAC. Thus TAC results in altered expression of genes in several pathways regulating both cardiac structure and function. However, for in vivo gene microarray experiments, it is critical to define adequate controls, perform rigorous statistical analysis, and provide validation by alternative methods.

  View details for DOI 10.1152/physiolgenomics.00040.2004

  View details for Web of Science ID 000224259700010

  View details for PubMedID 15292486

• Linearity versus cross-talk: Biological models and the role of the society for pediatric research in the 21st century Annual Meeting of the Pediatric-Academic-Societies/Society-for-Pediatric-Research Bernstein, D. NATURE PUBLISHING GROUP. 2004: 177–83

  View details for DOI 10.1203/PDR.0000132661.55523.BF

  View details for Web of Science ID 000222842200004

  View details for PubMedID 15181187

• Identifying cardiac transplant rejection in children: Diagnostic utility of echocardiography, right heart catheterization and endomyocardial biopsy data JOURNAL OF HEART AND LUNG TRANSPLANTATION Rosenthal, D. N., Chin, C., Nishimura, K., Perry, S. B., Robbins, R. C., Reitz, B., Bernstein, D., Feinstein, J. A. 2004; 23 (3): 323-329

  Abstract

  There has been a continued search for alternative diagnostic techniques that do not necessitate endomyocardial biopsy for diagnosing rejection in cardiac transplant recipients. The purpose of this study is to evaluate the role of echocardiography and hemodynamic catheterization data compared with endomyocardial biopsy results, in rejection surveillance for the pediatric heart transplant recipient.A prospective, blinded evaluation was performed utilizing echocardiographic and standard right heart catheterization parameters to predict acute rejection episodes.Forty-nine patients underwent 281 biopsies. Two groups were defined: those with Grade <2 rejection and those with grade > or =2 rejection. None of the echocardiographic variables showed significant differences between the study groups and all group data were within normal limits. Mixed venous saturation, mean right atrial pressure, right ventricular end-diastolic pressure and mean pulmonary artery pressure were found to be statistically significant between groups. Receiver-operator characteristic (ROC) curves were constructed to determine the extent to which the various parameters were clinically useful. The ROC found little clinical usefulness for all variables, including those found to be statistically significant.Differences in both echocardiographic and hemodynamic data were not clinically significant between the 2 groups of patients. Although many of the catheterization-derived parameters were statistically significant, they did not permit effective discrimination between groups. This is the only clinically relevant application of such data and may explain the conflicting previous reports. It is only through analyses such as ROC that the clinical application (or lack thereof) can be appreciated in this population.

  View details for DOI 10.1016/S1053-2498(03)00209-2

  View details for PubMedID 15019642

• Risk factors for recurrent rejection in pediatric heart transplantation: A multicenter experience JOURNAL OF HEART AND LUNG TRANSPLANTATION Chin, C., Naftel, D. C., Singh, T. P., Blume, E. D., Luikart, H., Bernstein, D., Gamberg, P., Kirklin, J. K., Morrow, W. R. 2004; 23 (2): 178-185

  Abstract

  Cardiac allograft rejection remains as a primary cause of death in the first 3 years after pediatric heart transplantation. Multiple episode of acute rejection in adult heart transplant recipients may accelerate the development of graft vasculopathy. We sought to quantify the time-related probability of recurrent rejection and identify risk factors for the development of recurrent rejection.We analyzed data from 847 pediatric recipients who underwent transplantation between January 1, 1993 and December 31, 1998 at 22 centers in the Pediatric Heart Transplant Study (PHTS). Recurrent rejection and risk factors were evaluated using univariate and multivariate analyses.Five hundred fifty two patients had 1,072 rejection events and were the subject of the analyses. The highest risk of recurrent rejection occurs within 1 month after resolution of a previous rejection episode. Risk factors for recurrent rejection include the number of previous rejection events, the elapsed time since a previous rejection episode, and subjects of either Hispanic or African-American descent. Rejection associated with hemodynamic compromise and late rejection is associated with higher mortality.Recurrent rejection is a risk factor for mortality, especially in the presence of hemodynamic compromise. This association appears independent of the time post-transplantation. Use of surveillance biopsies appears warranted throughout the life of the transplant individual. Retransplantation should be considered among these subjects with recurrent rejection.

  View details for DOI 10.1016/S1053-2498(03)00059-7

  View details for Web of Science ID 000188759100004

  View details for PubMedID 14761765

• Atrial tachyarrhythmias and permanent pacing after pediatric heart transplantation JOURNAL OF HEART AND LUNG TRANSPLANTATION Collins, K. K., Thiagarajan, R. R., Chin, C., Dubin, A. M., Van Hare, G. F., Robbins, R. C., Bernstein, D., Berul, C. I., Blume, E. D. 2003; 22 (10): 1126-1133

  Abstract

  Atrial tachyarrhythmias have been reported in as high as 50% of adult heart recipients. Limited information is available on arrhythmias in pediatric transplant patients. Our objective was to determine the prevalence and significance of atrial tachyarrhythmias and permanent pacing following pediatric heart transplantation.A retrospective review of the medical records, electrocardiograms, and Holter recordings of all consecutive patients following heart transplantation at Children's Hospital, Boston (n = 104) and Lucile Packard Children's Hospital, Stanford (n = 123) was performed. The study group consisted of 227 patients with a median age at transplant of 10.2 yrs (1 day-23.3 yrs).Atrial tachyarrhythmias occurred in 32 patients (14%) at a median of 15 days post-transplant (1 day-9.2 yrs) and included atrial flutter (n = 13), atrial fibrillation (n = 7), ectopic atrial tachycardia (n = 5), atrioventricular reciprocating tachycardia or atrioventricular node reentry (n = 5), and other (n = 2). Atrial flutter was the only tachyarrhythmia associated with allograft rejection (6/13 atrial flutter vs. 0/7 atrial fibrillation vs. 0/5 ectopic atrial tachycardia, p = 0.03). Patients with atrial fibrillation had a 2.5 fold (95%CI 1.7-3.5) higher risk of death or retransplant compared to patients without atrial fibrillation. Ectopic atrial tachycardia tended to occur in younger recipients compared to atrial fibrillation and flutter (2.7 yrs vs 18.6 yrs and 8.5 yrs respectively, p = 0.06) and was associated with a benign clinical course. There was no association between atrial tachyarrhythmias and graft ischemic time, surgical technique, or coronary artery disease. Pacemakers were required in 12 patients (5.2%), 7 with sinus node dysfunction and 5 for intermittent complete atrioventricular block. There was no consistent association between the need for permanent pacing and coronary artery disease, rejection, or surgical technique.Atrial tachyarrhythmias and permanent pacing were uncommon in this cohort of pediatric heart transplant recipients. Association with cardiac rejection, clinical course, and mortality varied depending on the tachyarrhythmia mechanism.

  View details for DOI 10.1016/S1053-2498(02)01193-2

  View details for Web of Science ID 000185764400007

  View details for PubMedID 14550822

• Exercise assessment of transgenic models of human cardiovascular disease PHYSIOLOGICAL GENOMICS Bernstein, D. 2003; 13 (3): 217-226

  Abstract

  Exercise provides one of the most severe, yet physiological, stresses to the intact cardiovascular system and is a major determinant of the utilization of metabolic substrates. The adaptations to exercise are the result of a coordinated response of multiple organ systems, including cardiovascular, pulmonary, endocrine-metabolic, immunologic, and skeletal muscle. With the proliferation of genetically altered murine models of cardiovascular disease, the importance of developing methods of accurate physiological phenotyping is critical. There are numerous examples of transgenic models in which the baseline cardiovascular phenotype is unchanged or minimally changed from the wild type, only to become manifest during the stress of exercise testing. In this review, we cover the basics of the murine cardiovascular response to exercise and the importance of attending to strain differences, compare different exercise methodologies (constant workload treadmill, incremental workload treadmill, swimming) and hemodynamic monitoring systems, and examine the murine response to exercise conditioning. Several examples where exercise studies have contributed to the elucidation of cardiovascular phenotypes are reviewed: the beta-adrenergic receptor knockouts, phospholamban knockout, dystrophin knockout (mdx), and the mutant alpha-myosin heavy chain (R403Q) transgenic.

  View details for DOI 10.1152/physiolgenomics.00188.2002

  View details for Web of Science ID 000182853000005

  View details for PubMedID 12746466

• Microarray analysis of gene expression after transverse aortic constriction in mice Annual Meeting of the Pediatric-Academic-Societies/Society-for-Pediatric-Research Zhao, M. M., Chow, A., Powers, J., Fajardo, G., Bernstein, D. NATURE PUBLISHING GROUP. 2003: 36A–36A

  View details for Web of Science ID 000181897900204

• Efficacy and safety of atorvastatin after pediatric heart transplantation JOURNAL OF HEART AND LUNG TRANSPLANTATION Chin, C., Gamberg, P., Miller, J., Luikart, H., Bernstein, D. 2002; 21 (11): 1213-1217

  Abstract

  Lipid abnormalities are prevalent after pediatric and adult heart transplantation. 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors are efficacious and safe and can lower the incidence of graft coronary artery disease after heart transplantation in adults. Given the high prevalence of lipid abnormalities and the increased recognition of graft coronary disease in children, we retrospectively investigated the efficacy and safety of atorvastatin among pediatric heart transplant recipients.Thirty-eight patients were started on atorvastatin 48.2 +/- 54.4 months after transplantation. Atorvastatin dosage was 0.2 +/- 0.1 mg/kg per day. No patient had changes in drug dose unless there was evidence for rhabdomyolysis, myositis or an asymptomatic rise in creatine kinase above normal. Laboratory studies included total cholesterol, triglycerides; high, low and very low-density lipoproteins (HDL, LDL and VLDL, respectively); creatine kinase; creatine; and serum alanine transaminase.Significant declines in total cholesterol (20%), triglyceride (18%) and LDL (26%) were observed after starting atorvastatin therapy. There were no significant changes in HDL or VLDL compared with baseline. There were also no differences in alanine transaminase pre- vs post-atorvastatin therapy. Complications included muscle pain (n = 2) and asymptomatic elevations in creatine kinase (n = 2). Two of these 4 patients developed rhabdomyolysis. Excluding these 4 patients, creatine kinase did not rise compared with baseline. No patient developed alterations in renal function.Use of atorvastatin in pediatric heart transplant recipients is effective in lowering total cholesterol, triglyceride and LDL without altering HDL levels. Complications included rhabdomyolysis, seen in 5%. Baseline and routine screening of creatine kinase should be employed in all pediatric patients undergoing HMG-CoA reductase inhibitor therapy.

  View details for Web of Science ID 000179183900006

  View details for PubMedID 12431495

• Abnormal cardiac function associated with sympathetic nervous system hyperactivity in mice AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Brum, P. C., Kosek, J., Patterson, A., Bernstein, D., Kobilka, B. 2002; 283 (5): H1838-H1845

  Abstract

  alpha(2A)-Adrenergic receptors (ARs) in the midbrain regulate sympathetic nervous system activity, and both alpha(2A)-ARs and alpha(2C)-ARs regulate catecholamine release from sympathetic nerve terminals in cardiac tissue. Disruption of both alpha(2A)- and alpha(2C)-ARs in mice leads to chronically elevated sympathetic tone and decreased cardiac function by 4 mo of age. These knockout mice have increased mortality, reduced exercise capacity, decreased peak oxygen uptake, and decreased cardiac contractility relative to wild-type controls. Moreover, we observed significant abnormalities in the ultrastructure of cardiac myocytes from alpha(2A)/alpha(2C)-AR knockout mice by electron microscopy. Our results demonstrate that chronic elevation of sympathetic tone can lead to abnormal cardiac function in the absence of prior myocardial injury or genetically induced alterations in myocardial structural or functional proteins. These mice provide a physiologically relevant animal model for investigating the role of the sympathetic nervous system in the development and progression of heart failure.

  View details for DOI 10.1152/ajpheart.01063.2001

  View details for Web of Science ID 000178625800012

  View details for PubMedID 12384461

• Cardiovascular and metabolic alterations in mice lacking beta 1- and beta 2-adrenergic receptors TRENDS IN CARDIOVASCULAR MEDICINE Bernstein, D. 2002; 12 (7): 287-294

  Abstract

  Targeted disruption of murine beta-adrenergic receptor (beta-AR) genes has helped to clarify the role of specific beta-AR subtypes in regulating cardiovascular development and function. In the mouse, the beta1-AR is primarily responsible for sympathetic regulation of both cardiac chronotropy and inotropy. In contrast, all three beta-ARs play a role in regulating peripheral vascular tone. The impact of ablation of both beta1- and beta2-ARs on cardiac development and on resting cardiovascular and metabolic parameters is remarkably minimal. However, exercise stress reveals additional important contributions of beta1- and beta2-ARs to cardiovascular performance.

  View details for Web of Science ID 000178580700002

  View details for PubMedID 12458090

• Long-term follow-up after total lymphoid irradiation in pediatric heart transplant recipients JOURNAL OF HEART AND LUNG TRANSPLANTATION Chin, C., Hunt, S., Robbins, R., Hoppe, R., Reitz, B., Bernstein, D. 2002; 21 (6): 667-673

  Abstract

  Total lymphoid irradiation (TLI) is used to treat recurrent allograft rejection. Short-term success and complication rates have been reported in pediatric and adult cardiac transplant populations. We report the long-term efficacy and safety of TLI in treating intractable rejection in pediatric patients.Eight pediatric patients were treated with TLI (7 for recurrent rejection, 1 for risk of medication non-compliance). Therapy consisted of a mid-plane dose of 8 Gy administered with a 6-MeV linear accelerator using an anterior-posterior opposed technique. We reviewed outcomes for a total of 40 patient-years of follow-up.We encountered rejection (>Grade 2 by International Society for Heart and Lung Transplantation criteria) in 56.7% +/- 34.7% of biopsies performed within 90 days before TLI. Rejection rates dropped to 3.1% +/- 8.8% within the first 90 days (p < 0.005) after therapy and remained low at 5.6% +/- 1.3% (p < 0.05) during the first year after completion of TLI. Median time from TLI to the first subsequent rejection episode was 305 days (range, 77-1,920 days). Long-term follow-up (>3 years) of 5 patients demonstrated a continuing low incidence of rejection. Non-Hodgkin's lymphoma was diagnosed in 1 of 8 patients, graft coronary artery disease in 4 of 8 patients, and restrictive cardiomyopathy in 1 of 8 patients after TLI.Total lymphoid irradiation is an effective treatment for recurrent rejection and has short- and long-term efficacy. Morbid events may include cancer, graft coronary artery disease, and restrictive cardiomyopathy.

  View details for Web of Science ID 000176074500008

  View details for PubMedID 12057700

• Infant heart transplantation at Stanford: Growth and neurodevelopmental outcome PEDIATRICS Fleisher, B. E., Baum, D., Brudos, G., Burge, M., Carson, E., Constantinou, J., Duckworth, J., Gamberg, P., Klein, P., Luikart, H., Miller, J., Stach, B., Bernstein, D. 2002; 109 (1): 1-7

  Abstract

  To evaluate the growth and neurodevelopmental outcome of 18 surviving Stanford patients who received heart transplantations before their second birthday.We compared the growth and neurodevelopmental outcome of these 18 patients with a second group of age-matched comparison patients who underwent other heart surgery requiring cardiopulmonary bypass.Difficulties with growth and development were more common in the transplant group as were neurologic abnormalities. Speech and language delays as well as hearing problems were also more common in the transplant group.Multicenter prospective longitudinal neurodevelopmental outcome studies of infant heart transplant patients should be conducted to provide a more efficient basis for evaluating management protocols and assessment of long-term outcomes and of the need for early intervention services.

  View details for Web of Science ID 000173006600019

  View details for PubMedID 11773534

• Survey of current practices in use of amiodarone and implantable cardioverter defibrillators in pediatric patients with end-stage heart failure AMERICAN JOURNAL OF CARDIOLOGY Dubin, A. M., Van Hare, G. F., Collins, K. K., Bernstein, D., Rosenthal, D. N. 2001; 88 (7): 809-?

  View details for Web of Science ID 000171374300022

  View details for PubMedID 11589857

• L-Arginine enhances aerobic exercise capacity in association with augmented nitric oxide production JOURNAL OF APPLIED PHYSIOLOGY Maxwell, A. J., Ho, H. V., Le, C. Q., Lin, P. S., Bernstein, D., Cooke, J. P. 2001; 90 (3): 933-938

  Abstract

  We tested whether supplementation with L-arginine can augment aerobic capacity, particularly in conditions where endothelium-derived nitric oxide (EDNO) activity is reduced. Eight-week-old wild-type (E(+)) and apolipoprotein E-deficient mice (E(-)) were divided into six groups; two groups (LE(+) and LE(-)) were given L-arginine (6% in drinking water), two were given D-arginine (DE(+) and DE(-)), and two control groups (NE(+) and NE(-)) received no arginine supplementation. At 12-16 wk of age, the mice were treadmill tested, and urine was collected after exercise for determination of EDNO production. NE(-) mice demonstrated a reduced aerobic capacity compared with NE(+) controls [maximal oxygen uptake (VO(2 max)) of NE(-) = 110 +/- 2 (SE) vs. NE(+) = 122 +/- 3 ml O(2). min(-1). kg(-1), P < 0.001]. This decline in aerobic capacity was associated with a diminished postexercise urinary nitrate excretion. Mice given L-arginine demonstrated an increase in postexercise urinary nitrate excretion and aerobic capacity in both groups (VO(2 max) of LE(-) = 120 +/- 1 ml O(2). min(-1). kg(-1), P < 0.05 vs. NE(-); VO(2 max) of LE(+) = 133 +/- 4 ml O(2). min(-1). kg(-1), P < 0.01 vs. NE(+)). Mice administered D-arginine demonstrated an intermediate increase in aerobic capacity in both groups. We conclude that administration of L-arginine restores exercise-induced EDNO synthesis and normalizes aerobic capacity in hypercholesterolemic mice. In normal mice, L-arginine enhances exercise-induced EDNO synthesis and aerobic capacity.

  View details for Web of Science ID 000167051400024

  View details for PubMedID 11181603

• Efficacy and safety of atorvastatin after pediatric cardiac transplantation. journal of heart and lung transplantation Chin, C., Gamberg, P., Miller, J., Luikart, H., Bernstein, D. 2001; 20 (2): 230-?

  View details for PubMedID 11250440

• Outcome while awaiting heart transplantation in children: A comparison of congenital heart disease and cardiomyopathy JOURNAL OF HEART AND LUNG TRANSPLANTATION Rosenthal, D. N., Dubin, A. M., Chin, C., Falco, D., Gamberg, P., Bernstein, D. 2000; 19 (8): 751-755

  Abstract

  Outcomes for children who undergo heart transplantation differ for children with congenital heart disease as compared to those with structurally normal hearts. Similar data have not been reported for these groups of patients for the morbidity and mortality associated with waiting for a donor. We report these data.A retrospective review was performed for all pediatric patients who were listed for heart transplantation at Stanford from 1977 to 1996, comparing mortality and major morbidity for patients with congenital heart disease and those with cardiomyopathy and structurally normal hearts.There were 96 patients who met study criteria, of whom 67 were successfully transplanted. The median waiting time was 23 days. Survival at 30 days was 93% and at 90 days was 81%, with no difference between groups. Major complications were identified in 38% of patients with structurally normal hearts, vs 9% of patients with congenital heart disease (p < 0.001).Overall mortality is similar for patients with congenital heart disease and those with structurally normal hearts while listed for heart transplantation, but patients with congenital heart disease have fewer episodes of major morbidity during this time.

  View details for Web of Science ID 000089041400005

  View details for PubMedID 10967268

• Lipoprotein abnormalities are highly prevalent in pediatric heart transplant recipients. Pediatric transplantation Chin, C., Rosenthal, D., Bernstein, D. 2000; 4 (3): 193-199

  Abstract

  The role of hyperlipidemia in graft coronary artery disease (GCAD) is controversial although hyper-triglyceridemia is an independent risk factor. Recent studies show that 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) inhibitors decrease the incidence of GCAD in adults. The incidence of GCAD in pediatric patients is lower than in adults; it is not clear whether age-related differences in lipid metabolism account for some of this protection. This study was performed to: characterize the lipoprotein profile in children after heart transplantation; demonstrate that total cholesterol (TC) is a poor marker for underlying lipoprotein abnormalities; and to compare lipid abnormalities in patients who had been converted from cyclosporin A (CsA) to tacrolimus. Seventy-one determinations of fasting lipoprotein profiles were performed in a cohort of 28 children. Each child had at least two determinations on separate occasions. TC, low-density lipoprotein (LDL), and serum triglyceride (TG) levels were categorized as abnormal if greater than the 75th percentile for age and gender. A high-density lipoprotein (HDL) level less than the 25th percentile was considered abnormal. Immunosuppression included CsA or tacrolimus, azathioprine, and prednisone. We found that 90% of the patients studied had abnormalities of either TG or HDL. In contrast, LDL tended to be normal when adjusted for age and gender. TC was a poor indicator of any underlying abnormality in TG, LDL, or HDL. In patients converted to tacrolimus, no significant differences were found in the levels of TG, LDL or HDL compared with each patient's respective values while receiving CsA. Hence, lipoprotein abnormalities among pediatric heart transplant recipients are highly prevalent. TC is a poor screening tool in the evaluation for lipid abnormalities. Lipoprotein profiles remain statistically unchanged after conversion from CsA to tacrolimus.

  View details for PubMedID 10933319

• Safety and utility of the routine surveillance biopsy in pediatric patients 2 years after heart transplantation JOURNAL OF PEDIATRICS Chin, C., Akhtar, M. J., Rosenthal, D. N., Bernstein, D. 2000; 136 (2): 238-242

  Abstract

  The standard for diagnosing allograft rejection after heart transplantation is the endomyocardial biopsy, but the value of routine surveillance biopsies after 2 years after transplant is controversial. The objective of this study was to determine the necessity and safety of surveillance biopsies and to correlate rejection with signs and symptoms beyond the second post-transplant anniversary in pediatric patients.We reviewed the results of 899 biopsies and coincident clinical histories in 56 pediatric patients, comprising 314 patient-years of follow-up. Patients were classified as having symptoms or not based on a blinded review of their clinical status and echocardiograms. Biopsies were classified as negative or positive with established criteria.After biopsies performed less than 2 years after transplant or as a follow-up for a positive biopsy were excluded, 481 biopsies were available for analysis, of which 20 (4%) were positive. Positive biopsies were found in 15 (3%) of 456 biopsies in patients without symptoms compared with 5 (20%) of 25 biopsies in patients with symptoms. Patients with symptoms were 6 times more likely to have a positive biopsy compared with patients without symptoms. Of the positive rejection episodes, 75% occurred in patients without symptoms.Although rejection is uncommon in pediatric patients greater than 2 years after transplant, episodes of treatable allograft rejection can occur in the absence of clinical signs and symptoms. This study emphasizes the safety of and the need to continue to perform routine surveillance biopsies in patients without symptoms, even after the second post-transplant year.

  View details for Web of Science ID 000085289400023

  View details for PubMedID 10657832

• The use of advanced-age donor hearts adversely affects survival in pediatric heart transplantation. Pediatric transplantation Chin, C., Miller, J., Robbins, R., Reitz, B., Bernstein, D. 1999; 3 (4): 309-314

  Abstract

  There is a limited supply of adequate donor hearts for cardiac transplantation. The safety of using advanced-age donor hearts has been debated in adult transplantation but has not been studied previously in pediatric recipients. In this retrospective study, survival of 79 pediatric heart transplant recipients was reviewed. Pediatric recipient groups were stratified based on donor age (group 1 donor age > 40 yr, n = 5; group 2 donor age < or = 40 yr, n = 74). Survival of 267 adolescent (ages 11-17) heart transplant recipients in the United Network for Organ Sharing (UNOS) database was also reviewed. Patients were likewise divided into two groups based on donor age (> 40 yr, n = 12; < or = 40 yr, n = 255). Survival at one yr was 20% in group 1 vs. 78% in group 2 (p < 0.005). Cause of death in all group 1 patients was graft failure secondary to acute rejection. Analysis of risk of death was only significantly attributable to the age of the donor. The increased risk attributable to advanced donor age was also supported by the UNOS data. The UNOS one and two-year Kaplan-Meier survival curves were significantly lower in adolescent patients who received donor hearts > 40 yr of age. One-year survival was 58% (older donors) vs. 85% (younger donors, p < 0.005) and two-year survival was 44% (older donors) vs. 79% (younger donors, p < 0.005). Advanced-age donor hearts should be contraindicated in pediatric transplantation with the exception of critically ill patients who may not be able to wait for a younger heart.

  View details for PubMedID 10562976

• Heart transplantation in children: indications. Report of the Ad Hoc Subcommittee of the Pediatric Committee of the American Society of Transplantation (AST). Pediatric transplantation Fricker, F. J., Addonizio, L., Bernstein, D., Boucek, M., Boucek, R., Canter, C., Chinnock, R., Chin, C., Kichuk, M., Lamour, J., Pietra, B., Morrow, R., Rotundo, K., Shaddy, R., Schuette, E. P., Schowengerdt, K. O., Sondheimer, H., Webber, S. 1999; 3 (4): 333-342

  Abstract

  This review details the indications for heart transplantation in children. Contraindications have evolved from absolute to relative. Controversial issues remain and this paper represents a consensus of more than a dozen centers that have programs that remain active performing pediatric heart transplants.

  View details for PubMedID 10562980

• QT dispersion predicts ventricular arrhythmia in pediatric cardiomyopathy patients referred for heart transplantation JOURNAL OF HEART AND LUNG TRANSPLANTATION Dubin, A. M., Rosenthal, D. N., Chin, C., Bernstein, D. 1999; 18 (8): 781-785

  Abstract

  QT dispersion has been used in stratifying risk for sudden death in adults with dilated cardiomyopathy, but its role in the pediatric population has not been delineated.We reviewed electrocardiograms in pediatric patients with dilated cardiomyopathy referred for heart transplantation, to evaluate the role of QT dispersion in predicting malignant arrhythmias in these patients. Three groups were defined: Group I (n = 13) had dilated cardiomyopathy and malignant ventricular arrhythmias, Group II (n = 13) had dilated cardiomyopathy with no ventricular arrhythmias and Group III (n = 30) consisted of normals. QT dispersion was defined as the duration of the shortest QT subtracted from that of the longest. In addition, the standard deviation of the QT intervals was calculated for each ECG, using 12 leads.QT dispersion was significantly prolonged in Group I (97 +/- 33 msec) compared to Group II (74 +/- 19 msec) and Group III (42 +/- 17 msec). QT standard deviation was also prolonged in Group I (30 +/- 11 msec) vs Group II (22 +/- 5 msec) and Group III (13 +/- 4 msec). Using a threshold value of 90 msec for QT dispersion or 25 msec for QT standard deviation, a sensitivity of 78% and a specificity of 70% was obtained for identifying patients who would subsequently develop ventricular arrhythmias.In pediatric heart transplant candidates with dilated cardiomyopathy, QT dispersion and QT standard deviation identify patients at higher risk for the development of malignant ventricular arrhythmia. This simple test can be helpful in the evaluation and management of these patients awaiting transplantation.

  View details for Web of Science ID 000082347500007

  View details for PubMedID 10512525

• Abnormal regulation of the sympathetic nervous system in alpha(2A)-adrenergic receptor knockout mice MOLECULAR PHARMACOLOGY Altman, J. D., Trendelenburg, A. U., MacMillan, L., Bernstein, D., Limbird, L., Starke, K., Kobilka, B. K., Hein, L. 1999; 56 (1): 154-161

  Abstract

  alpha2-Adrenergic receptors (ARs) play a key role in regulating neurotransmitter release in the central and peripheral sympathetic nervous systems. To date, three subtypes of alpha2-ARs have been cloned (alpha2A, alpha2B, and alpha2C). Here we describe the physiological consequences of disrupting the gene for the alpha2A-AR. Mice lacking functional alpha2A subtypes were compared with wild-type (WT) mice, with animals lacking the alpha2B or alpha2C subtypes, and with mice carrying a point mutation in the alpha2A-AR gene (alpha2AD79N). Deletion of the alpha2A subtype led to an increase in sympathetic activity with resting tachycardia (knockout, 581 +/- 21 min-1; WT, 395 +/- 21 min-1), depletion of cardiac tissue norepinephrine concentration (knockout, 676 +/- 31 pg/mg protein; WT, 1178 +/- 98 pg/mg protein), and down-regulation of cardiac beta-ARs (Bmax: knockout, 23 +/- 1 fmol/mg protein; WT, 31 +/- 2 fmol/mg protein). The hypotensive effect of alpha2 agonists was completely absent in alpha2A-deficient mice. Presynaptic alpha2-AR function was tested in two isolated vas deferens preparations. The nonsubtype-selective alpha2 agonist dexmedetomidine completely blocked the contractile response to electrical stimulation in vas deferens from alpha2B-AR knockout, alpha2C-AR knockout, alpha2AD79N mutant, and WT mice. The maximal inhibition of vas deferens contraction by the alpha2 agonist in alpha2A-AR knockout mice was only 42 +/- 9%. [3H]Norepinephrine release studies performed in vas deferens confirmed these findings. The results indicate that the alpha2A-AR is a major presynaptic receptor subtype regulating norepinephrine release from sympathetic nerves; however, the residual alpha2-mediated effect in the alpha2A-AR knockout mice suggests that a second alpha2 subtype (alpha2B or alpha2C) also functions as a presynaptic autoreceptor to inhibit transmitter release.

  View details for Web of Science ID 000081240600019

  View details for PubMedID 10385696

• Targeted disruption of the beta 2 adrenergic receptor gene JOURNAL OF BIOLOGICAL CHEMISTRY Chruscinski, A. J., Rohrer, D. K., Schauble, E., Desai, K. H., Bernstein, D., Kobilka, B. K. 1999; 274 (24): 16694-16700

  Abstract

  beta-Adrenergic receptors (beta-ARs) are members of the superfamily of G-protein-coupled receptors that mediate the effects of catecholamines in the sympathetic nervous system. Three distinct beta-AR subtypes have been identified (beta1-AR, beta2-AR, and beta3-AR). In order to define further the role of the different beta-AR subtypes, we have used gene targeting to inactivate selectively the beta2-AR gene in mice. Based on intercrosses of heterozygous knockout (beta2-AR +/-) mice, there is no prenatal lethality associated with this mutation. Adult knockout mice (beta2-AR -/-) appear grossly normal and are fertile. Their resting heart rate and blood pressure are normal, and they have a normal chronotropic response to the beta-AR agonist isoproterenol. The hypotensive response to isoproterenol, however, is significantly blunted compared with wild type mice. Despite this defect in vasodilation, beta2-AR -/- mice can still exercise normally and actually have a greater total exercise capacity than wild type mice. At comparable workloads, beta2-AR -/- mice had a lower respiratory exchange ratio than wild type mice suggesting a difference in energy metabolism. beta2-AR -/- mice become hypertensive during exercise and exhibit a greater hypertensive response to epinephrine compared with wild type mice. In summary, the primary physiologic consequences of the beta2-AR gene disruption are observed only during the stress of exercise and are the result of alterations in both vascular tone and energy metabolism.

  View details for Web of Science ID 000080780400007

  View details for PubMedID 10358008

• Cardiovascular and metabolic alterations in mice lacking both beta 1-and beta 2-adrenergic receptors JOURNAL OF BIOLOGICAL CHEMISTRY Rohrer, D. K., Chruscinski, A., Schauble, E. H., Bernstein, D., Kobilka, B. K. 1999; 274 (24): 16701-16708

  Abstract

  The activation state of beta-adrenergic receptors (beta-ARs) in vivo is an important determinant of hemodynamic status, cardiac performance, and metabolic rate. In order to achieve homeostasis in vivo, the cellular signals generated by beta-AR activation are integrated with signals from a number of other distinct receptors and signaling pathways. We have utilized genetic knockout models to test directly the role of beta1- and/or beta2-AR expression on these homeostatic control mechanisms. Despite total absence of beta1- and beta2-ARs, the predominant cardiovascular beta-adrenergic subtypes, basal heart rate, blood pressure, and metabolic rate do not differ from wild type controls. However, stimulation of beta-AR function by beta-AR agonists or exercise reveals significant impairments in chronotropic range, vascular reactivity, and metabolic rate. Surprisingly, the blunted chronotropic and metabolic response to exercise seen in beta1/beta2-AR double knockouts fails to impact maximal exercise capacity. Integrating the results from single beta1- and beta2-AR knockouts as well as the beta1-/beta2-AR double knock-out suggest that in the mouse, beta-AR stimulation of cardiac inotropy and chronotropy is mediated almost exclusively by the beta1-AR, whereas vascular relaxation and metabolic rate are controlled by all three beta-ARs (beta1-, beta2-, and beta3-AR). Compensatory alterations in cardiac muscarinic receptor density and vascular beta3-AR responsiveness are also observed in beta1-/beta2-AR double knockouts. In addition to its ability to define beta-AR subtype-specific functions, this genetic approach is also useful in identifying adaptive alterations that serve to maintain critical physiological setpoints such as heart rate, blood pressure, and metabolic rate when cellular signaling mechanisms are perturbed.

  View details for Web of Science ID 000080780400008

  View details for PubMedID 10358009

• American Pediatric Society Society for Pediatric Research code of responsible conduct of research PEDIATRIC RESEARCH Bernstein, D. 1999; 45 (5): 613-614

  View details for Web of Science ID 000080086700001

  View details for PubMedID 10231853

• Phospholamban deficiency does not compromise exercise capacity AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Desai, K. H., Schauble, E., Luo, W. S., Kranias, E., Bernstein, D. 1999; 276 (4): H1172-H1177

  Abstract

  Deficiency of phospholamban (PLB) results in enhancement of basal murine cardiac function and an attenuated response to beta-adrenergic stimulation. To determine whether the absence of PLB also reduces the reserve capacity of the murine cardiovascular system to respond to stress, we evaluated the heart rate (HR), blood pressure, and metabolic responses of PLB-deficient (PLB-/-) mice to graded treadmill exercise (GTE). PLB-/- mice were hypertensive at rest (125 +/- 19 vs. 109 +/- 16 mmHg, P < 0.05) but had normal tachycardic and hypotensive responses to isoproterenol. The HR response to GTE was normal; however, the hypertension in PLB-/- mice normalized at peak exercise. Their exercise capacities, as measured by duration of exercise and peak oxygen consumption (VO2), were normal. The oxygen pulse (VO2/HR) curve was also normal in PLB-/- mice, suggesting an ability to appropriately increase stroke volume and oxygen extraction during GTE, despite an inability to increase beta-adrenergically stimulated cardiac contractility. Thus deficiency of PLB, although resulting in diminished beta-adrenergic inotropic reserve, does not compromise cardiac performance during exercise.

  View details for Web of Science ID 000079554200009

  View details for PubMedID 10199840

• Impaired aerobic capacity in hypercholesterolemic mice: partial reversal by exercise training AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Niebauer, J., Maxwell, A. J., Lin, P. S., Tsao, P. S., Kosek, J., Bernstein, D., Cooke, J. P. 1999; 276 (4): H1346-H1354

  Abstract

  The present study assessed whether impaired aerobic capacity previously observed in hypercholesterolemic mice is reversible by exercise training. Seventy-two 8-wk-old female C57BL/6J wild-type (+, n = 42) and apolipoprotein E-deficient (-, n = 30) mice were assigned to the following eight interventions: normal chow, sedentary (E+, n = 17; E-, n = 8) or exercised (E+ex, n = 13; E-ex, n = 7) and high-fat chow, sedentary (E+chol, n = 6; E-chol, n = 8) or exercised (E+chol-ex, n = 6; E-chol-ex, n = 7). Mice were trained on a treadmill 2 x 1 h/day, 6 days/wk, for 4 wk. Cholesterol levels correlated inversely with maximum oxygen uptake (r = -0.35; P < 0. 02), which was blunted in all hypercholesterolemic sedentary groups (all P < 0.05). Maximum oxygen uptake improved in all training groups but failed to match E+ex (all P < 0.05). Vascular reactivity and nitric oxide (NO) synthesis correlated with anaerobic threshold (r = 0.36; P < 0.025) and maximal distance run (r = 0.59; P < 0.007). We conclude that genetically induced hypercholesterolemia impairs aerobic capacity. This adverse impact of hypercholesterolemia on aerobic capacity may be related to its impairment of vascular NO synthesis and/or vascular smooth muscle sensitivity to nitrovasodilators. Aerobic capacity is improved to the same degree by exercise training in normal and genetically hypercholesterolemic mice, although there remains a persistent difference between these groups after training.

  View details for Web of Science ID 000079554200030

  View details for PubMedID 10199861

• Limb blood flow during exercise is dependent on nitric oxide CIRCULATION Maxwell, A. J., Schauble, E., Bernstein, D., Cooke, J. P. 1998; 98 (4): 369-374

  Abstract

  We have recently reported that hypercholesterolemia reduces aerobic exercise capacity in mice and that this is associated with a reduced endothelium-dependent vasodilator function, endothelium-derived nitric oxide (EDNO) production, and urinary nitrate excretion. These findings led us to test the hypothesis that EDNO production contributes significantly to limb blood flow during exercise and to determine whether loss of EDNO production is responsible for the decline in exercise capacity observed in hypercholesterolemia.Twelve-week-old wild-type (E+; n=9) and apoE-deficient (E-; n=9) C57BL/6J mice were treadmill-tested to measure indices defining exercise capacity on a metabolic chamber-enclosed treadmill capable of measuring oxygen uptake and carbon dioxide excretion. Urine was collected before and after treadmill exercise for determination of vascular NO production assessed by urinary nitrate excretion. The wild-type mice were then given nitro-L-arginine (E+LNA) in the drinking water (6 mg/dL) for 4 days before undergoing a second treadmill testing and urinary nitrate measurement. An additional set of 12-week-old wild-type mice was divided into 2 groups: 1 receiving regular water (E+; n=8) and 1 administered LNA for 4 days (E+LNA; n=8). These mice, along with an additional set of E mice (n=8), underwent treadmill testing to determine maximal oxygen uptake (VO2max). The mice were then cannulated such that the tip of the tubing was positioned in the ascending aorta. Fluorescent microspheres (20000) were infused into the carotid cannula while the mice were sedentary and again while approaching VO2max. When the mice were euthanized, the running muscles were collected and fluorescence intensity was measured to determine the peak-exercise redistribution of blood flow to the running muscles (expressed as percentage of total cardiac output, %COrm) during both states. Both E+LNA and E- mice demonstrated a markedly reduced postexercise urinary nitrate excretion, aerobic capacity, and %COrm at VO2max compared with E+.EDNO contributes significantly to limb blood flow during exercise. Conditions that reduce EDNO production disturb the hyperemic response to exercise, resulting in a reduced exercise capacity.

  View details for Web of Science ID 000074984800014

  View details for PubMedID 9711943

• Alterations in dynamic heart rate control in the beta(1)-adrenergic receptor knockout mouse AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Rohrer, D. K., Schauble, E. H., Desai, K. H., Kobilka, B. K., Bernstein, D. 1998; 274 (4): H1184-H1193

  Abstract

  beta 1-Adrenergic receptors (beta 1-ARs) are key targets of sympathetic nervous system activity and play a major role in the beat-to-beat regulation of cardiac chronotropy and inotropy. We employed a beta 1-AR gene knockout model to test the hypothesis that beta 1-AR function is critical for maintenance of resting heart rate and baroreflex responsiveness and, on the basis of its important role in regulating chronotropy and inotropy, is also required for maximal exercise capacity. Using an awake unrestrained mouse model, we demonstrate that resting heart rate and blood pressure are normal in beta 1-AR knockouts and that the qualitative responses to baroreflex stimulation are intact. Chronotropic reserve in beta 1-AR knockouts is markedly limited, with peak heart rates approximately 200 beats/min less than wild types. During graded treadmill exercise, heart rate is significantly depressed in beta 1-AR knockouts at all work loads, but despite this limitation, there are no reductions in maximal exercise capacity or metabolic indexes. Thus, in mice, the beta 1-AR is not essential for either maintenance of resting heart rate or for maximally stressed cardiovascular performance.

  View details for Web of Science ID 000072839800015

  View details for PubMedID 9575921

• Elective transplant pneumonectomy JOURNAL OF PEDIATRIC SURGERY DeAnda, A., Cahill, J. L., Bernstein, D., Starnes, V. A., Reitz, B. A. 1998; 33 (4): 655-656

  Abstract

  The use of a single lung transplant, modified with removal of the middle lobe of the donor right lung, has been described for a term neonate with respiratory distress secondary to right-sided congenital diaphragmatic hernia. The successful transplant allowed the patient to be successfully weaned from extracorporeal membrane oxygenation. Because of the early age of the patient at transplantation (3 weeks), it was unclear how the patient's left lung would develop, and there was uncertainty regarding the risk of life-time immunosuppression. By the age of 4 years, 10 months, she was demonstrating some failure to thrive, hypertension, and hirsutism, obvious side effects of chronic immunosuppression. The question was raised as to the potential for transplant pneumonectomy. A ventilation-perfusion scan demonstrated a decrease of right lung ventilation compared with the immediate postoperative period (27% versus 43%); right heart catheterization with balloon occlusion of the right main pulmonary artery suggested that the patient would tolerate right pneumonectomy. After discussion with the family, the patient underwent transplant pneumonectomy via a right posterolateral approach. Findings at the time of operation included mild to moderate adhesions as well as recurrence of the diaphragmatic hernia. She tolerated the procedure well and was discharged home on the fifth postoperative day with cessation of her immunosuppression. The immediate and medium-term success of this procedure suggests the potential for temporizing transplantation as a palliation to promote survival until the remaining native lung can provide sufficient ventilation.

  View details for Web of Science ID 000073170200027

  View details for PubMedID 9574774

• The developmental and physiological consequences of disrupting genes encoding beta 1 and beta 2 adrenoceptors. Advances in pharmacology (San Diego, Calif.) Rohrer, D. K., Bernstein, D., Chruscinski, A., Desai, K. H., Schauble, E., Kobilka, B. K. 1998; 42: 499-501

  View details for PubMedID 9327949

• Survival and risk factors for death after cardiac transplantation in infants - A multi-institutional study CIRCULATION Canter, C., Naftel, D., Caldwell, R., Chinnock, R., Pahl, E., Frazier, E., Kirklin, J., Boucek, M., Morrow, R., Appleton, R. S., Ramaciotti, C., Fricker, F. J., Zales, V. R., Sterba, R., Latson, L., Fraser, C., Addonizio, L. J., MOSKOWITZ, W., Rossi, A., Shaddy, R., Bash, S., Bernstein, D., Towbin, J., McGiffin, D. C., Alejos, J., Boucek, M. M., Madden, M., Ring, W. S., Dodd, D. A. 1997; 96 (1): 227-231

  View details for Web of Science ID A1997XJ44200037

• Predicting outcome after listing for heart transplantation in children: Comparison of Kaplan-Meier and parametric competing risk analysis JOURNAL OF HEART AND LUNG TRANSPLANTATION McGiffin, D. C., Naftel, D. C., Kirklin, J. K., Morrow, W. R., Towbin, J., Shaddy, R., Alejos, J., Rossi, A., Frazier, E., Heilman, K. J., Pacheao, D. K., Sterba, R., Latson, L., Fraser, C., Fitzgerald, R., Platt, L., Appleton, R. S., Kurbat, M., Friedman, B., Fricker, F. J., Fleeger, T., Pahl, E., Stapleton, P., Ring, W. S., Copeland, M., Clark, B., Sands, B., Addonizio, L. J., Douglas, J., KNAUF, D., Harker, K., West, L. J., GILDNER, J., Caldwell, R. L., Flaspohler, T., Chinnock, R. E., Johnston, J., Robie, S., Mullen, G. M., Laff, M. A., McGregor, C. G., Henke, P., Suddendorf, S., Timmons, M., MOSKOWITZ, W., Flattery, M., Cabalka, A., Okane, M., Hoffman, F., SEIMERS, N., Bruhn, P., Reutzez, T., Courtney, M., Reller, M. D., Starling, R., Holt, C., Bullock, E., Zahka, K. G., Hanisch, D., Canter, C., Bash, S., Stubles, C. E., Faulkner, S., Stanstrom, M. L., Bernstein, D., Gamberg, P., Price, J., McGiffin, D. C., Boucek, M. M., Mashburn, C., Luna, M., Crowley, D., Callow, L., Boucek, R., DiSano, S., Dodd, D. A., Burger, J. 1997; 16 (7): 713-722

  View details for Web of Science ID A1997XN72100002

• Cardiovascular indexes in the mouse at rest and with exercise: New tools to study models of cardiac disease AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Desai, K. H., Sato, R., Schauble, E., Barsh, G. S., Kobilka, B. K., Bernstein, D. 1997; 272 (2): H1053-H1061

  Abstract

  Manipulations of the murine genome that alter cardiovascular function have created the need for methods to study cardiovascular physiology in genetically altered animals in vivo. We adapted chronic physiological measurement techniques to the nonanesthetized, nonrestrained murine model, established strain-specific cardiovascular and metabolic norms, and evaluated responses to anesthesia, exercise, and adrenergic stimulation. Anesthesia resulted in alterations in heart rate (HR), blood pressure (BP), and O2 consumption (V(O2)) and CO2 production (V(CO2)) for up to 6 h postoperatively. There were significant interstrain differences in resting values of HR and BP Graded treadmill exercise resulted in linear increases in HR, V(O2), V(CO2), and respiratory exchange ratio (RER) similar to those seen in larger species. Response to beta-adrenergic stimulation showed a classic sigmoidal dose-response curve; however, there was very little tachycardiac response to vagal blockade, indicating low resting vagal tone. This study demonstrates the feasibility of performing chronic cardiovascular measurements in nonanesthetized mice and stresses the importance of allowing for anesthetic recovery and strain variability. Murine cardiovascular responses to exercise can be reliably measured and are qualitatively similar to those in humans.

  View details for Web of Science ID A1997WJ80900057

  View details for PubMedID 9124413

• Developmental and afterload stress regulation of heat shock proteins in the ovine myocardium Society-for-Pediatric-Research Meeting Strandness, E., Bernstein, D. INT PEDIATRIC RESEARCH FOUNDATION, INC. 1997: 51–56

  Abstract

  Heat shock proteins (hsps) are produced in the myocardium in response to stresses such as ischemia, hyperthermia, and increased afterload. The role of these stress proteins in the developing myocardium is unknown. Expression of the inducible (hsp 72) and cognate (hsc 73) hsps was determined in the immature ovine myocardium during the perinatal transition, and their role in subsequent myocardial growth was examined. hsp synthesis was also studied during acute afterload stress in newborns by aortic banding to a gradient of 50 torr for 4 h. Expression of the inducible (hsp 72) isoform is developmentally regulated in both right and left ventricles: low levels in the fetus, increasing throughout development, and peaking in the 14-25-d newborn and adult. The cognate (hsc 73) isoform remains unchanged during development in the left ventricle but decreases with age in the right ventricle. The inducible (hsp 72) isoform is also developmentally regulated in the lung, increasing postnatally to a peak in the 14-25-d-old and adult sheep. Finally, newborn myocardium demonstrated a rapid increase in hsp expression in response to afterload stress, similar to that seen in the adult.

  View details for Web of Science ID A1997VY68500008

  View details for PubMedID 8979289

• Cardiovascular regulation in mice lacking alpha(2)-adrenergic receptor subtypes b and c SCIENCE Link, R. E., Desai, K., Hein, L., Stevens, M. E., Chruscinski, A., Bernstein, D., Barsh, G. S., Kobilka, B. K. 1996; 273 (5276): 803-805

  Abstract

  alpha2-Adrenergic receptors (alpha2ARs) are essential components of the neural circuitry regulating cardiovascular function. The role of specific alpha2AR subtypes (alpha2a, alpha2b, and alpha2c) was characterized with hemodynamic measurements obtained from strains of genetically engineered mice deficient in either alpha2b or alpha2c receptors. Stimulation of alpha2b receptors in vascular smooth muscle produced hypertension and counteracted the clinically beneficial hypotensive effect of stimulating alpha2a receptors in the central nervous system. There were no hemodynamic effects produced by disruption of the alpha2c subtype. These results provide evidence for the clinical efficacy of more subtype-selective alpha2AR drugs.

  View details for Web of Science ID A1996VB42900045

  View details for PubMedID 8670422

• Targeted disruption of the mouse beta 1-adrenergic receptor gene: Developmental and cardiovascular effects PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Rohrer, D. K., Desai, K. H., Jasper, J. R., Stevens, M. E., Regula, D. P., Barsh, G. S., Bernstein, D., Kobilka, B. K. 1996; 93 (14): 7375-7380

  Abstract

  At least three distinct beta-adrenergic receptor (beta-AR) subtypes exist in mammals. These receptors modulate a wide variety of processes, from development and behavior, to cardiac function, metabolism, and smooth muscle tone. To understand the roles that individual beta-AR subtypes play in these processes, we have used the technique of gene targeting to create homozygous beta 1-AR null mutants (beta 1-AR -/-) in mice. The majority of beta 1-AR -/- mice die prenatally, and the penetrance of lethality shows strain dependence. Beta l-AR -/- mice that do survive to adulthood appear normal, but lack the chronotropic and inotropic responses seen in wild-type mice when beta-AR agonists such as isoproterenol are administered. Moreover, this lack of responsiveness is accompanied by markedly reduced stimulation of adenylate cyclase in cardiac membranes from beta 1-AR -/- mice. These findings occur despite persistent cardiac beta 2-AR expression, demonstrating the importance of beta 1-ARs for proper mouse development and cardiac function, while highlighting functional differences between beta-AR subtypes.

  View details for Web of Science ID A1996UW79200098

  View details for PubMedID 8693001

• CARDIAC TRANSPLANTATION FOR HYPERTROPHIC CARDIOMYOPATHY ASSOCIATED WITH SENGERS-SYNDROME ANNALS OF THORACIC SURGERY Robbins, R. C., Bernstein, D., Berry, G. J., VanMeurs, K. P., Frankel, L. R., Reitz, B. A. 1995; 60 (5): 1425-1427

  Abstract

  Sengers' syndrome is a rare condition consisting of congenital cataracts, mitochondrial myopathy, and hypertrophic cardiomyopathy. The syndrome is transmitted in an autosomal recessive pattern. Progressive cardiac failure is the cause of death in most patients. This report describes cardiac transplantation for the treatment of the cardiomyopathy associated with Sengers' syndrome.

  View details for PubMedID 8526648

• COLCHICINE AND CYTOCHALASIN-B ENHANCE CYCLIC-AMP ACCUMULATION VIA POSTRECEPTOR ACTIONS JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS Jasper, J. R., Post, S. R., Desai, K. H., Insel, P. A., Bernstein, D. 1995; 274 (2): 937-942

  Abstract

  The role of cytoskeletal microtubules and microfilaments in modulating cAMP generation in S49 lymphoma cells was investigated using the agents colchicine and cytochalasin B, respectively, which are known to disrupt these structures. A 1-hr pretreatment of S49 cells with 10 microM colchicine typically enhanced maximal isoproterenol-(beta-adrenergic receptor) stimulated cAMP accumulation by 100%, whereas cytochalasin B increased isoproterenol-stimulated cAMP by 30%. The combination of colchicine and cytochalasin B synergistically enhanced agonist-stimulated cAMP to 225% over control values. A synergistic increase in cAMP accumulation was also observed in cells treated with the agonist prostaglandin E1 or cholera toxin (which activates the stimulatory guanine nucleotide regulatory (Gs) protein). Colchicine and cytochalasin B did not ablate the inhibitory effects of somatostatin or the stimulatory effect of pertussis toxin treatment on beta-receptor-stimulated cAMP accumulation, indicating that these cytoskeletal disrupting agents do not enhance responsiveness in S49 cells via alterations in the inhibitory guanine nucleotide regulatory protein pathway. Moreover, colchicine, but not cytochalasin B treatment, enhances expression of isoproterenol-promoted 3H-forskolin binding in intact cells (a measure of Gs/adenylyl cyclase coupling). Thus, colchicine and cytochalasin B appear to enhance signaling in the Gs/adenylyl cyclase pathway by alterations of components distal to hormone receptors, most likely at the Gs protein and/or via cAMP generation. These results imply that microtubules and microfilaments can interact in the regulation of this pathway and that increases in cellular cAMP may contribute to the action of drugs that alter function of these cytoskeletal elements.

  View details for Web of Science ID A1995RN98300048

  View details for PubMedID 7636757

• ARTERIAL SWITCH AND RESECTION OF HEPATIC HEMANGIOENDOTHELIOMA ANNALS OF THORACIC SURGERY Robbins, R. C., Chin, C., Yun, K. L., Berry, G. J., Bernstein, D., Reitz, B. A. 1995; 59 (6): 1575-1577

  Abstract

  We report on the management of a neonate undergoing arterial switch for transposition of the great arteries and concomitant resection of a hepatic infantile hemangioendothelioma. A preoperative aortogram demonstrated the arterial supply of the hepatic hemangioendothelioma. Pulmonary artery hypertension and myocardial ischemia were noted after separation from cardiopulmonary bypass. Resection of the hepatic malformation produced an immediate reduction in pulmonary hypertension and resolution of the myocardial ischemia. The patient had an uneventful postoperative recovery.

  View details for Web of Science ID A1995RB62100052

  View details for PubMedID 7771849

• Pediatric cardiac transplantation. The Stanford experience. Circulation Sarris, G. E., Smith, J. A., Bernstein, D., Griffin, M. L., Pitlick, P. T., Baum, D., Billingham, M. E., Oyer, P. E., Stinson, E. B., Starnes, V. A. 1994; 90 (5): II51-5

  Abstract

  Cardiac transplantation for children with endstage heart disease has become an accepted form of therapy and is being practiced with increasing frequency and improving short-term outcome.To assess the medium-term outcome of pediatric cardiac transplantation, we analyzed our experience with 72 patients under the age of 18 (range, 0.1 to 17.7 years; mean, 9 +/- 6.4 [SD]) who underwent orthotopic cardiac transplantation at Stanford University between 1977 and 1993. There were 38 male and 34 female patients. Preoperative diagnoses included congenital heart disease in 24 (33%), idiopathic cardiomyopathy in 27 (37%), viral cardiomyopathy in 12 (17%), and familial cardiomyopathy in 7 (10%) patients. Immunosuppressive management has evolved over time and has included a tapering schedule of steroids, azathioprine, rabbit antithymocyte globulin, cyclosporine in all patients after 1980, and induction with OKT3 since 1987. Operative mortality rate was 12.5 +/- 4.0% (mean +/- 70% confidence intervals). Actuarial survival estimates at 1, 5, and 10 years are 75 +/- 7.1%, 60 +/- 6.4%, and 50 +/- 8.1% (mean +/- 1 SEM), respectively. Causes of death included infection in 8 (28% of deaths), rejection in 7 (24%), graft coronary disease in 5 (17%), pulmonary hypertension in 4 (14%), and nonspecific graft failure in 2 (7%) patients. Survival rates were similar for patients over and those under age 10 years (including the infant cohort of 18 patients transplanted since 1986). Currently, there are 43 patients alive, all in New York Heart Association functional class I. Only 22 +/- 5.6% of patients were free of rejection at 1 year, but 86 +/- 5.4% were free of rejection-related death at 10 years. At 1 year, only 37 +/- 6% of patients were free from any infection, but 88 +/- 4.2% remained free of infection-related death at 5 years. Actuarial freedom from graft coronary artery disease (angiographic or autopsy proven) was 85 +/- 6.6% at 5 years and from coronary artery disease-related death was 91 +/- 4.7%.These data demonstrate satisfactory medium-term outcome of cardiac transplantation in selected pediatric patients with end-stage heart disease, but further progress is necessary to more effectively control rejection, infection, and graft coronary disease.

  View details for PubMedID 7955282

• SUCCESSFUL THROMBOLYSIS OF A THROMBOSED ST-JUDE MEDICAL MITRAL PROSTHESIS IN A 2-MONTH-OLD INFANT JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Smith, J. A., Desai, K., Bernstein, D., Reitz, B. A. 1994; 108 (1): 187-187

  View details for Web of Science ID A1994NW67700034

  View details for PubMedID 8028369

• NEOPLASTIC DISORDERS AFTER PEDIATRIC HEART-TRANSPLANTATION CIRCULATION Bernstein, D., Baum, D., Berry, G., Dahl, G., Weiss, L., Starnes, V. A., Gamberg, P., Stinson, E. B. 1993; 88 (5): 230-237

  View details for Web of Science ID A1993ME83400032

• Neoplastic disorders after pediatric heart transplantation. Circulation Bernstein, D., Baum, D., Berry, G., Dahl, G., Weiss, L., Starnes, V. A., Gamberg, P., Stinson, E. B. 1993; 88 (5): II230-7

  Abstract

  Because of their life-long requirement for immunosuppressive therapy, neoplastic disorders could represent a significant threat to long-term survival in infants and children after heart transplantation. This study determined the incidence and clinical spectrum of neoplastic disorders in 80 pediatric patients who underwent heart transplantation between 1974 and 1992.Follow-up ranged from 6 to 189 months (mean, 50.0 months). Tumors occurred in 10 patients (12.5%). Time to detection ranged from 3.3 to 139.2 months (mean, 52.7 months). Tumor incidence was greatest in 9 patients transplanted before the cyclosporine era (44%) compared with the subsequent 71 patients (8.5%, P < .05). There was no increase in risk related to sex, age, underlying disease, or blood type; however, patients with tumors received higher initial doses of cyclosporine and prednisone and had more rejection episodes in the first 3 months (P < .05). There was an increased risk associated with anti-thymocyte globulin (33%, P < .05) but not with OKT3 (6%, P = NS). There were eight lymphoproliferative disorders (four B-cell, one T-cell, three not determined) and one hepatocellular and one squamous cell carcinomas. Six cases of lymphoproliferative disorder had in situ evidence of Epstein-Barr virus. Patients were treated by reducing immunosuppression (7), radiotherapy (2), and chemotherapy (1). There were five deaths: two tumor related and the others due to rejection, renal failure, and infection. Of 5 survivors, 1 had tumor recurrence 4 years after diagnosis, and 4 are disease free.Tumors represent a small but serious long-term risk to pediatric heart transplant recipients. The incidence in children transplanted in the cyclosporine era is similar to that in adults, and the majority of tumors are lymphoproliferative disorders that often regress by reducing immunosuppression.

  View details for PubMedID 8222159

• HEART-TRANSPLANTATION IN INFANCY PROGRESS IN PEDIATRIC CARDIOLOGY Boucek, M. M., Bernstein, D. 1993; 2 (4): 20-28

  View details for Web of Science ID A1993MM33200005

• PRIMARY STRUCTURE OF THE MOUSE BETA(1)-ADRENERGIC RECEPTOR GENE BIOCHIMICA ET BIOPHYSICA ACTA Jasper, J. R., Link, R. E., Chruscinski, A. J., Kobilka, B. K., Bernstein, D. 1993; 1178 (3): 307-309

  Abstract

  The mouse beta 1-adrenergic receptor was isolated from a genomic library and cloned into pBluescript SK-. Characterization of the clone revealed an open reading frame which encodes a predicted protein of 466 amino acids. The mouse beta 1 receptor is 92.7% identical to the human sequence, 98.5% identical to the rat sequence, and contains a consensus site for N-linked glycosylation at Asn-15 and a cAMP-dependent protein kinase phosphorylation site at Ser-301.

  View details for Web of Science ID A1993LX80300011

  View details for PubMedID 8395893

• Update on cardiac transplantation in infants and children. Critical care medicine Bernstein, D. 1993; 21 (9): S354-5

  View details for PubMedID 8365223

• ALTERATION IN GS-MEDIATED SIGNAL TRANSDUCTION IN S49 LYMPHOMA-CELLS TREATED WITH INHIBITORS OF MICROTUBULES JOURNAL OF BIOLOGICAL CHEMISTRY Leiber, D., Jasper, J. R., Alousi, A. A., Martin, J., Bernstein, D., Insel, P. A. 1993; 268 (6): 3833-3837

  Abstract

  We have assessed the possible interaction between the microtubular component of the cytoskeleton and signal transducing GTP-binding (G) proteins by examining the ability of colchicine and vinblastine (two microtubule disrupters) to alter Gs and Gi protein activity in S49 lymphoma cells. Treatment of wild type S49 cells with cholchicine and vinblastine increased beta-adrenergic agonist- and prostaglandin (PG) E1-stimulated formation of cAMP. The microtubular inhibitor nocodazole also enhanced isoproterenol-stimulated cAMP accumulation, whereas the inactive analog of colchicine, beta-lumicolchicine, did not have this action. Based on data obtained with wild type, cyc-, and UNC S49 cells, we determined that enhancement in cyclic AMP accumulation is proximal to the catalytic (C) unit of adenylylcyclase, distal to hormone receptors, and seems to be located on Gs. Treatment with colchicine increased guanosine 5'-(gamma-thio)triphosphate-stimulated accumulation of cAMP in permeabilized wild type cells. The increase in activity of Gs appeared not to result from a change in the intracellular concentration of GTP. Treatment of cells with colchicine or vinblastine also increased the amount of the alpha s-C complex, as assessed by the binding of [3H]forskolin to intact cells at 37 degrees C. In contrast to the observed effect on Gs, treatment of wild type S49 cells with colchicine failed to modify the degree of inhibition of cAMP formation produced by somatostatin, which acts via the activation of Gi. These data suggest that microtubules regulate the ability of Gs to interact with and activate the catalyst of adenylylcyclase.

  View details for Web of Science ID A1993KN53300010

  View details for PubMedID 8095044

• TRANSCRIPTIONAL REGULATION OF LEFT-VENTRICULAR BETA-ADRENERGIC RECEPTORS DURING CHRONIC HYPOXIA CIRCULATION RESEARCH Bernstein, D., Doshi, R., Huang, S., Strandness, E., Jasper, J. R. 1992; 71 (6): 1465-1471

  Abstract

  beta-Adrenergic receptor downregulation is the end result of cellular adaptation to prolonged agonist exposure. The factors mediating receptor downregulation include receptor phosphorylation, receptor movement from the plasma membrane to intracellular sites, and alterations in nascent receptor synthesis. We have previously demonstrated a downregulation of the left ventricular beta-receptor during chronic hypoxia in vivo. To determine the mechanism of this downregulation, we produced chronic hypoxia in seven newborn lambs by creating right ventricular outflow obstruction and an atrial septal defect. Oxygen saturation was reduced to 65-74% for 2 weeks. Six lambs served as normoxic controls. Sarcolemmal membrane and cytosolic fractions were prepared from left ventricular free wall samples. beta-Receptor density in each fraction was determined with the radioligand [125I]iodocyanopindolol. Steady-state levels of beta-receptor mRNA were determined by Northern blot analysis using a beta 1-adrenergic receptor cDNA probe. During chronic hypoxia, left ventricular membrane beta-adrenergic receptor density decreased by 55% (153 +/- 28 fmol/mg for hypoxic lambs versus 342 +/- 79 fmol/mg for control lambs, p < 0.05). There was no corresponding increase in beta-receptor density in the cytosolic fraction (23 +/- 3 fmol/mg for hypoxic lambs versus 33 +/- 9 fmol/mg for control lambs, p = NS), nor was there a significant change in the ratio of beta 1-receptor/beta 2-receptor subtypes as assessed by radioligand binding (beta 1 subtype, 84.1 +/- 10.1% for hypoxic lambs versus 93.2 +/- 8.8% for control lambs; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

  View details for Web of Science ID A1992JZ07200019

  View details for PubMedID 1330359

• CURRENT APPROACH TO HYPOPLASTIC LEFT HEART SYNDROME - PALLIATION, TRANSPLANTATION, OR BOTH JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Starnes, V. A., Griffin, M. L., Pitlick, P. T., Gundry, S., Bernstein, D., Baum, D., Ivens, K., Shumway, N. E. 1992; 104 (1): 189-195

  Abstract

  Over the past 3 years, 35 newborn infants have been referred for surgical management of hypoplastic left heart syndrome. Surgical palliation (first-stage Norwood) or cardiac transplantation was offered. Twenty-four families (68%) chose palliation and 11 families (32%) chose cardiac transplantation. Of the 11 infants listed for cardiac transplantation, five underwent transplantation. Because of a lack of donors after an average wait of 25 days (19 to 31), the remaining six infants underwent palliation, with no perioperative deaths. Of the 30 infants undergoing palliation, including crossovers, 20 (67%) survived the first operative stage. Among the last 19 infants undergoing palliation in 1990, the early survival was 84%. Risk factors determined for poor outcome were year of operation (p less than 0.001) and circulatory arrest time greater than 50 minutes (p less than 0.001). Among the 13 infants undergoing palliation with a circulatory arrest time of less than 50 minutes, there were 12 survivors (92%); among 12 having a circulatory arrest time of more than 50 minutes, there were four survivors (33%). At intermediate follow-up, six infants have undergone second-stage procedures (Glenn), with five survivors. There were eight late deaths, four caused by respiratory infections and four caused by cardiac problems, including a thrombosed shunt in one infant. Three of five infants are alive and doing well after cardiac transplantation. Size of aorta, tricuspid regurgitation, and ventricular wall thickness did not prove to be risk factors. Given the existing data, we believe these infants should be managed selectively on the basis of donor availability and family wishes.

  View details for Web of Science ID A1992JD13800025

  View details for PubMedID 1377313

• CARDIAC GROWTH AFTER PEDIATRIC HEART-TRANSPLANTATION CIRCULATION Bernstein, D., Kolla, S., Miner, M., PITLICK, P., Griffin, M., Starnes, V., Rowan, R., Billingham, M., Baum, D. 1992; 85 (4): 1433-1439

  Abstract

  To assess whether normal cardiac growth occurs after heart transplantation in the pediatric age group, we performed a study of 13 infants and children who underwent orthotopic heart transplantation at Stanford.The echocardiographic data from a population of 93 normal children were analyzed to determine estimates of the fifth, 25th, 50th, 75th, and 95th percentiles of the normal pediatric population. Growth curves for each of the cardiac dimensions were stratified into six classes representing each of the percentile bands, and dimensions for the 13 patients were tracked between early postoperative (early) and point of maximal follow-up (late). Results were compared by Student's paired t test to determine whether normal growth was occurring. The mean age at transplant was 5.0 +/- 1.3 years (mean +/- SEM) (range, 0.4-12.8 years), duration of follow-up was 3.1 +/- 0.4 years (1.3-5.8 years), and change in body surface area was 0.24 +/- 0.03 m2 (0.12-0.50 m2). Both right ventricular (RV) and left ventricular (LV) chamber dimensions were within the normal range at both early and late time points and grew normally as assessed by a lack of class changes. Early wall thickness measurements were above the 95th percentile in seven of 13 patients (LV), 12 of 13 patients (septum), and four of 13 patients (RV). Wall thickness measurements remained above normal, and there were no significant class changes at late follow-up. Histological examination in five patients showed markedly increased septal myocyte width, indicating myocyte hypertrophy. Atrial and great vessel anastomotic sites showed no evidence of obstruction by Doppler and catheterization studies.These data demonstrate that normal cardiac chamber dimensional growth occurs at greater than 3 years' follow-up after pediatric heart transplantation. Significant LV and septal (and to a lesser extent RV) hypertrophy persists and may have implications for long-term allograft growth and function.

  View details for Web of Science ID A1992HN04900024

  View details for PubMedID 1532543

• DECREASED SERUM INSULIN-LIKE GROWTH FACTOR-I ASSOCIATED WITH GROWTH FAILURE IN NEWBORN LAMBS WITH EXPERIMENTAL CYANOTIC HEART-DISEASE JOURNAL OF CLINICAL INVESTIGATION Bernstein, D., Jasper, J. R., Rosenfeld, R. G., Hintz, R. L. 1992; 89 (4): 1128-1132

  Abstract

  To determine whether chronic hypoxemia results in alterations in endocrine function that may contribute to growth failure, we measured growth hormone (GH), somatomedins (insulin-like growth factors I and II, IGF-I and IGF-2), hepatic growth hormone receptors, and circulating IGF-binding proteins IGFBP-3 and IGFBP-2 in 12 newborn lambs with surgically created pulmonic stenosis and atrial septal defect, and in 10 controls. During chronic hypoxemia (oxygen saturation of 60-74% for 2 wk), weight gain was 60% of control (hypoxemic, 135 +/- 20 vs. control, 216 +/- 26 g/d, P less than 0.02). IGF-I was decreased by 43% (hypoxemic 253.6 +/- 29.3 SE vs. control 448.0 +/- 75.5 ng/ml, P = 0.01), whereas GH was unchanged (19.9 +/- 5.1 vs. 11.9 +/- 3.0 ng/ml, NS). The increase in IGF-1 was associated with a decrease in IGFBP-3 (hypoxemic, 5.09 +/- 1.25 vs. control, 11.2 +/- 1.08 arbitrary absorbency units per mm (Au.mm), P less than 0.01), and increase in IGFBP-2 (0.47 +/- 0.03 vs. 0.19 +/- 0.13 Au.mm, P less than 0.05), but no significant downregulation of hepatic GH receptors (hypoxemic, 106.1 +/- 20.1 vs. control, 147.3 +/- 25.9 fmol/mg, NS). Thus, chronic hypoxemia in the newborn is associated with a decrease in IGF-I and IGFBP-3 in the face of normal GH. This suggests peripheral GH unresponsiveness, similar to protein-calorie malnutrition or GH receptor deficiency dwarfism, but mediated at a level distal to the hepatic GH receptor.

  View details for Web of Science ID A1992HL84000010

  View details for PubMedID 1372914

• ALTERATIONS IN POSTNATAL INTESTINAL FUNCTION DURING CHRONIC HYPOXEMIA PEDIATRIC RESEARCH Bernstein, D., Bell, J. G., Kwong, L., Castillo, R. O. 1992; 31 (3): 234-238

  Abstract

  Growth failure is a major complication of chronic hypoxemia, as seen in infants and children with cyanotic congenital heart disease. To determine whether chronic hypoxemia during infancy affects the gastrointestinal tract, we examined small intestinal growth and digestive enzyme activities in chronically hypoxemic newborn lambs and in age-matched controls. Chronic hypoxemia was produced by placing an inflatable occluder around the main pulmonary artery and performing a balloon atrial septostomy. Aortic oxygen saturation was reduced to 60-74% for 2 wk, after which the small intestine was removed for analysis. During chronic hypoxemia, somatic growth rate was decreased to 60% of control (hypoxemic, 135 +/- 20 versus control, 216 +/- 26 g/d, p less than 0.02). No differences in caloric intake were found (hypoxemic, 129 +/- 4 versus control, 128 +/- 4 kcal/kg/d). Chronic hypoxemia did not alter small intestinal growth, as measured by jejuno-ileal weight, jejuno-ileal length, mucosal weight, or mucosal protein or DNA contents. However, sp act of lactase, the principal disaccharidase of the infant lamb intestine, were significantly decreased (hypoxemic, 0.08 +/- 0.01 versus control, 0.146 +/- 0.03 units of enzyme activity/mg DNA, p less than 0.05), as were the total small intestinal contents of lactase (hypoxemic, 61.7 +/- 7.0 versus control, 120.6 +/- 21.7 units of enzyme activity, p less than 0.01). There also were decreases in specific and total activities of other digestive enzymes such as maltase, amino-oligopeptidase, and alkaline phosphatase in hypoxemic intestine that did not achieve statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

  View details for Web of Science ID A1992HF34600007

  View details for PubMedID 1561008

• HEART, HEART-LUNG, AND LUNG TRANSPLANTATION IN THE 1ST YEAR OF LIFE ANNALS OF THORACIC SURGERY Starnes, V. A., Oyer, P. E., Bernstein, D., Baum, D., Gamberg, P., Miller, J., Shumway, N. E. 1992; 53 (2): 306-310

  Abstract

  Seventeen infants less than 1 year of age have undergone heart (12), heart-lung (3), and lung (2) transplantation for end-stage cardiopulmonary disease. The infants undergoing heart transplantation had a mean age of 4.5 months (range, 19 days to 12 months) with the diagnosis of cardiomyopathy in 4 and congenital heart disease in 8. Four of the 8 patients (50%) had hypoplastic left heart syndrome. Actuarial survival at 1 and 2 years was 74% and compared favorably with the survival of older children at 1 and 2 years of 82% and 69%. The linearized rejection rate was less in infants as compared with children more than 1 year of age (0.61 versus 1.48 episodes per 100 patient days). In intermediate follow-up, no graft atherosclerosis has been noted. Immunosuppression has included a three-drug protocol of cyclosporine, azathioprine, and prednisone. A steroid taper to alternate day steroids or off completely by 6 months has been the goal and has been accomplished in 6 of 12 infants. Heart-lung and lung transplantation has been performed in 5 infants. One infant in each group died: 1 infant secondary to airway complications and sepsis and another due to pulmonary sepsis. A pulmonary lobe from a larger and older donor was transplanted into a 4-week-old infant as a single-lung transplant with good outcome. The 3 surviving infants are well 24, 18, and 2 months after transplantation. Obliterative bronchiolitis has not been clinically apparent in this group. These data support the clinical efficacy of heart, heart-lung, and lung transplantation in the first year of life.

  View details for Web of Science ID A1992HB90700022

  View details for PubMedID 1731673

• REGULATION OF ATRIAL AUTONOMIC RECEPTORS IN EXPERIMENTAL CYANOTIC HEART-DISEASE AMERICAN JOURNAL OF PHYSIOLOGY Doshi, R., Strandness, E., Bernstein, D. 1991; 261 (4): H1135-H1140

  Abstract

  During chronic hypoxemia, left ventricular beta-adrenergic receptor density is decreased and a dissociation occurs between increased chronotropic and decreased inotropic responses to chronically elevated sympathetic tone. To determine whether this dissociation was related to alterations in autonomic receptor populations in the right atrium, we studied right atrial cholinergic and beta-adrenergic receptors in chronically hypoxemic newborn lambs and in normoxemic controls. Heart rate response was determined by infusing isoproterenol at 0.1 or 0.5 microgram.kg-1.min-1. Muscarinic receptors were quantified with [3H]quinuclidinyl benzilate and beta-adrenergic receptors with [125I]iodocyanopindolol. Competition with ICI 118,551 was used to determine beta 1- vs. beta 2-receptor subtypes. In the hypoxemic lambs, isoproterenol resulted in a lesser percentage increase in heart rate (hypoxemic, 46 +/- 6% vs. control, 89 +/- 17%, P less than 0.05); however, because baseline heart rate was higher in the hypoxemic lambs (213 +/- 7 vs. 177 +/- 12 beats/min, P less than 0.05), maximal heart rate responses were similar (310 +/- 7 vs. 326 +/- 6 beats/min, NS). There was no change in receptor density or affinity of either muscarinic or beta-adrenergic receptors and no change in the proportion of beta 1- vs. beta 2-receptor subtypes. Thus the dissociation between the chronotropic and inotropic responses to chronic hypoxemia may be in part secondary to a differential regulation of beta-adrenergic receptors between the left ventricle and the right atrium.

  View details for Web of Science ID A1991GK86900023

  View details for PubMedID 1656786

• PEDIATRIC HEART-TRANSPLANTATION AT STANFORD - RESULTS OF A 15-YEAR EXPERIENCE PEDIATRICS Baum, D., Bernstein, D., Starnes, V. A., Oyer, P., PITLICK, P., STINSON, E., Shumway, N. 1991; 88 (2): 203-214

  Abstract

  The long-term results of pediatric heart transplantation were evaluated in 53 patients, aged 0.25 to 18.94 years, who received transplants at Stanford University Medical Center between 1974 and 1989. Indications for transplantation were idiopathic cardiomyopathy (68%), congenital heart disease (21%), endocardial fibroelastosis (8%), and doxorubicin cardiomyopathy (3%). Immunosuppression was achieved with combinations of cyclosporine, prednisone, and azathioprine. Thirty-seven of 42 recipients leaving the hospital after transplantation were alive and in New York Heart Association class I at study's end. Cumulative survival was 79% at 1 year, 76% at 3 years, and 69% at 5 years. Fourteen recipients have survived more than 5 years (5.1 to 12.4 years). Hospital readmission for illness has been infrequent, decreasing from 6.8 days to 0.9 days per year over 5 years. Eleven patients have required no rehospitalization. Posttransplant deaths were due to infection (19%), rejection (4%), pulmonary hypertension (4%), coronary artery disease (2%), and lymphoproliferative disease (2%). Retransplantation was required for intractable rejection in 4 patients and advanced coronary artery disease in 2. Hypertension and elevated blood urea nitrogen and creatinine levels were common in individuals receiving cyclosporine. Growth was often impaired in prepubertal children receiving daily prednisone. Based on this 15-year experience, it is concluded that heart transplantation represents a reasonable alternative for selected young patients with end-stage cardiac disease.

  View details for Web of Science ID A1991GA16400002

  View details for PubMedID 1861916

• EBSTEINS-ANOMALY APPEARING IN THE NEONATE - A NEW SURGICAL APPROACH JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Starnes, V. A., Pitlick, P. T., Bernstein, D., Griffin, M. L., Choy, M., Shumway, N. E. 1991; 101 (6): 1082-1087

  Abstract

  Ebstein's anomaly appearing during the neonatal period carries a high mortality rate. These infants exhibit cyanosis, acidosis, and congestive heart failure. The pathophysiologic characteristics consist of severe tricuspid regurgitation and functional pulmonary atresia. As a result of the inability of the right ventricle to generate forward flow through the pulmonary arteries, these infants remain dependent on ductal patency. Since May 1988, five newborn infants with severe Ebstein's anomaly have been admitted for treatment at our institution. At initial examination, they weighed 3.6 +/- 1.8 kg and had a mean oxygen tension of 29.6 +/- 2.3 mm Hg and a mean pH of 7.20 +/- 0.05. Chest roentgenography demonstrated a mean cardiothoracic ratio of 0.81 +/- 0.02. As determined by echocardiography, the right atria were massively enlarged, severe tricuspid regurgitation was present in all patients, and the pulmonary valves were not opening. All infants were dependent on prostaglandin E1 and attempts to wean them from this drug were unsuccessful. Palliative treatment consisted of tricuspid closure with autologous pericardium and an aortopulmonary shunt of 4 mm polytetrafluoroethylene tubing. There were no operative or late deaths. At discharge, mean oxygen tension was 42.2 +/- 0.85 mm Hg and mean systemic oxygen saturation was 83.2% +/- 1.94%. Infants have grown satisfactorily during the follow-up period. Three infants have since returned for further surgical intervention. One infant, at 11 months of age, underwent a Glenn anastomosis for progressive oxygen desaturation. Two infants have returned, at ages 23 and 22 months, for Fontan procedures, which represent their definitive operative management. We believe this new procedure offers excellent palliative treatment for Ebstein's anomaly in critically ill neonates. Feasibility of later definitive correction is demonstrated by the good results obtained with the Fontan procedure in two infants.

  View details for Web of Science ID A1991FQ11100018

  View details for PubMedID 2038202

• COMPARATIVE CIRCULATORY EFFECTS OF ISOPROTERENOL AND DOPAMINE IN LAMBS WITH EXPERIMENTAL CYANOTIC HEART-DISEASE PEDIATRIC RESEARCH Bernstein, D., Crane, C. 1991; 29 (4): 323-328

  Abstract

  To determine whether the hemodynamic responses to adrenergic agonists are altered during chronic hypoxemia secondary to an intracardiac right to left shunt, we studied seven lambs with surgically created pulmonic stenosis and atrial septal defect and nine controls during infusions of isoproterenol at 0.1 and 0.5 micrograms/kg/min and dopamine at 5 and 20 micrograms/kg/min. Isoproterenol increased heart rate by 89 +/- 17% in control but only 46 +/- 6% in experimental lambs (p less than 0.05). However, because resting heart rate was higher in experimental lambs (213 +/- 7 versus 177 +/- 12 beats/min, p less than 0.05), maximal heart rates were similar (310 +/- 7 versus 326 +/- 6 beats/min; NS). Cardiac output increased during isoproterenol from 219 +/- 20 to 425 +/- 54 mL/min/kg in experimental lambs (p less than 0.05) and, similarly, from 180 +/- 20 to 425 +/- 71 in controls (p less than 0.05) (experimental versus control; NS). Dopamine also increased cardiac output similarly in both groups, at both doses, but without changing heart rate. Isoproterenol did not alter aortic oxygen saturation and increased systemic oxygen transport more than oxygen consumption. In contrast, dopamine at both doses decreased aortic oxygen saturation in experimental lambs (rest, 71 +/- 2% versus dopamine, 59 +/- 2%; p less than 0.05). With dopamine, the increase in systemic oxygen transport was equalled by an increase in oxygen consumption. Thus, circulatory responses to isoproterenol are similar in lambs with experimental cyanotic heart disease and controls, although higher resting heart rate in the experimental lambs reduces chronotropic reserve.(ABSTRACT TRUNCATED AT 250 WORDS)

  View details for Web of Science ID A1991FE03600001

  View details for PubMedID 1852523

• Pediatric heart transplantation. Advances in pediatrics Bernstein, D., Starnes, V. A., Baum, D. 1990; 37: 413-439

  Abstract

  Heart transplantation has been performed successfully in the pediatric age group for just over 10 years, yet early results are encouraging, and this procedure has moved from the realm of experimental therapy to that of accepted medical practice for certain specific conditions. In infants and children with cardiomyopathies or with congenital heart disease for which no reasonable standard surgical alternative exists, heart transplantation offers the best hope for long-term survival. Most important, in those patients surviving heart transplantation, rehabilitation has been almost universally complete. Although the long-term prospects for pediatric heart transplant patients are still unknown, we have now accumulated sufficient experience in adults suggesting the potential for decades-long survival. Future improvements in diagnosis and treatment of rejection and prevention of the complications of immunosuppressive therapy will continue to improve the prospects for lifelong survival in these patients.

  View details for PubMedID 2264535

• DIFFERENTIAL REGULATION OF RIGHT AND LEFT-VENTRICULAR BETA-ADRENERGIC RECEPTORS IN NEWBORN LAMBS WITH EXPERIMENTAL CYANOTIC HEART-DISEASE JOURNAL OF CLINICAL INVESTIGATION Bernstein, D., Voss, E., Huang, S., Doshi, R., Crane, C. 1990; 85 (1): 68-74

  Abstract

  To determine whether chronic hypoxemia secondary to an intracardiac right-to-left shunt alters regulation of the myocardial beta-adrenergic receptor/adenylate cyclase system, we produced chronic hypoxemia in nine newborn lambs by creating right ventricular outflow obstruction and an atrial septal defect. Oxygen saturation was reduced to 65-74% for 2 wk. Eight lambs served as normoxemic controls. beta-receptor density (Bmax) and ligand affinity (KD) were determined with the radio-ligand [125I]iodocyanopindolol and adenylate cyclase activity determined during stimulation with isoproterenol, sodium fluoride (NaF), and forskolin. During chronic hypoxemia, Bmax decreased 45% (hypoxemic, 180.6 +/- 31.5 vs. control, 330.5 +/- 60.1 fmol/mg) in the left ventricle (exposed to hypoxemia alone) but was unchanged in the right ventricle (exposed to hypoxemia and pressure overload). KD was not different from control in either ventricle. Left ventricular isoproterenol-stimulated adenylate cyclase activity was decreased by 39% (30.0 +/- 4.3% increase vs. 44.1 +/- 9.5% increase) whereas right ventricular adenylate cyclase activity was unchanged. Stimulation of adenylate cyclase with NaF or forskolin was not different from control in either ventricle. Circulating epinephrine was increased fourfold whereas circulating and myocardial norepinephrine were unchanged. These data demonstrate a down-regulation of the left ventricular beta-adrenergic receptor/adenylate cyclase system during chronic hypoxemia secondary to an intracardiac right-to-left shunt.

  View details for Web of Science ID A1990CH52200011

  View details for PubMedID 2153153

• HEART-TRANSPLANTATION IN CHILDREN JOURNAL OF HEART TRANSPLANTATION Starnes, V. A., Bernstein, D., Oyer, P. E., GAMBERG, P. L., Miller, J. L., Baum, D., Shumway, N. E. 1989; 8 (1): 20-26

  Abstract

  Heart transplantation in children is being performed with increasing frequency. As experience has accrued, problems of rejection, graft atherosclerosis, and growth have been noted. Seventeen children (seven boys and 10 girls) between the ages of 5 months and 14 years have undergone heart transplantation since 1981. The preoperative diagnosis was cardiomyopathy in 13 children, congenital heart disease in two, and endocardial fibroelastosis in two. Immunosuppressive therapy has included a tapering schedule of cyclosporine, azathioprine, and prednisone. There are 13 children alive, with four hospital deaths (two of infection, one of rejection, and one of graft failure). Rejection occurs as frequently in children as in adults. Two children have undergone retransplantation for rejection. Long-term hemodynamics are normal. Growth has been delayed in two of five children who are younger than age 10 years. Kidney function remains stable. Rehabilitation is 100% among the discharged patients. Heart transplantation in children represents an effective therapeutic modality. Heart transplantation in the young has emphasized morbidity caused by current immunosuppressive agents.

  View details for Web of Science ID A1989T169600004

  View details for PubMedID 2647927