Clinical Focus


  • Pulmonary Arterial Hypertension
  • Hereditary Hemorrhagic Telangiectasia
  • Chronic Right Heart Failure
  • Arteriovenous Malformations
  • Investigator Initiated Clinical Trials
  • Rare Genetic Diseases
  • Pulmonary Disease

Academic Appointments


Administrative Appointments


  • Director, HHT Center of Excellence, Stanford University (2019 - Present)

Honors & Awards


  • Mid-Career Women Faculty Leadership Seminar (MidWIMS), Association of American Medical Colleges (Dec 2022)
  • High-Potential Women Leaders Program, Stanford University Graduate School of Business (Jan-Feb 2022)
  • R01 - Understanding and targeting right ventricular adaptation and failure, NIH / NHLBI (2021 - 2025)
  • Peer Reviewed Medical Investigator-Initiated Research Award: Arteriovenous Malformations, Department of Defense (2019 -2022)
  • Peer Reviewed Medical Investigator-Initiated Research Award: BMPR2 and RV Function in CHD, Department of Defense (2017 - 2020)
  • R01 - Targeting Novel BMPR2 modifiers in Pulmonary Hypertension with Repurposed Drugs, NIH / NHLBI (2016 - 2021)
  • Young Physician Scientist Award, American Society of Clinical Investigation (April 2015)
  • K08 Career development award, NIH (2011-2016)
  • Supplemental award of the Pulmonary Hypertension Association (PHA), Pulmonary Hypertension Association (2011 - 2016)
  • Helmholtz International Research Group Award, Helmholtz Zentrum Muenchen, Germany (2013-2016)
  • Seed Grant - Phase II Clinical Trial, SPARK and Spectrum Stanford (2012-2014)
  • Seed Grant - Phase II Clinical Trial, Wall Center of Pulmonary Vascular Disease (2012-2014)
  • Seed Grant- BMP signaling in the RV, Cardiovascular Institute Stanford (2013-2014)
  • Manuscript Award, Cardiovascular Institute at Stanford (Feb 2014)
  • Poster Award, Excellence Cluster Cardio-Pulmonary System (ECCPS) and Pulmonary Vascular Research Institute (PVRI) (Jan 2014)
  • Winner of Poster competition, Cardiovascular Institute Stanford (Sept 2012)
  • Seed Grant - Small Molecule High Throughout Screen, Wall Center of Pulmonary Vascular Disease (2012)
  • Postdoctoral Research Fellowship, Pulmonary Hypertension Association (2003-2005)

Boards, Advisory Committees, Professional Organizations


  • Chair, 3CPR Early Career Committee, American Heart Association (2021 - 2023)
  • Member of Cure HHT Research Network _ CZI Rare as ONE, Cure HHT.org (2022 - Present)
  • Nominating Committee, American Thoracic Society (2020 - 2021)
  • Pulmonary Circulation Program Committee, American Thoracic Society (2013 - 2019)
  • Member, Pulmonary Vascular Research Institute (2014 - Present)
  • Member at large, European Respiratory Society (2000 - Present)
  • Member at large, American Thoracic Society (1998 - Present)

Professional Education


  • Fellowship: Stanford University Pulmonary and Critical Care Fellowship (2009) CA
  • Fellowship: Stanford University (2008) CA
  • Fellowship: Lucile Packard Children's Hospital (2006) CA
  • Residency: Medizinische Hochschule Hannover (2002) Germany
  • Medical Education: University Hospital Freiburg (1995) Germany

Patents


  • Edda Spiekerkoetter, Md Khadem Ali, Adam Andruska. "United StatesUse of Tyrosine Kinase Inhibitor for the Treatment of Hereditary Hemorrhagic Telangiectasia and Pulmonary Arterial Hypertension", Leland Stanford Junior University, Nov 22, 2022
  • Edda Spiekerkoetter, Svenja Dannewitz, Xuefei Tian, Purvesh Khatri. "United States Patent CA3064275A1 Enzastaurin and Fragile Histidine Trial (FHIT) Increasing Agents for the Treatment of Pulmonary Hypertension", Leland Stanford Junior University, May 18, 2018
  • Edda Spiekerkoetter, Marlene Rabinovitch, David Solow-Cordero, Phil Beachy. "United States Patent 61481317 Low-Dose FK506 for the treatment of Pulmonary Arterial Hypertension", Leland Stanford Junior University, May 2, 2012

Current Research and Scholarly Interests


The limited treatment options for patients with end-stage pulmonary arterial hypertension (PAH) and right heart failure that I observed as a Pulmonary and Critical Care fellow at Hannover Medical School in Germany in the early 2000s were the reason I sought out basic research training in vascular biology under the mentorship of Dr. Marlene Rabinovitch at Stanford University.

As a physician scientist I strive to better understand the pathogenesis and underlying pathobiology of pulmonary and cardiovascular diseases such as PAH, arteriovenous malformations in hereditary hemorrhagic telangiectasia (HHT) and right heart failure to develop more effective treatments for these diseases. We use 3-D deep tissue imaging, mouse mutants and lineage tracing approaches to answer questions about the molecular and anatomic structure of blood vessels in concert with the extracellular matrix in the lung and the heart in health and disease.

A particular focus in my laboratory is the involvement of the BMPR2/TGF-b pathway in vascular biology. We use High-Throughput Screening techniques, induced pluripotent stem cells and bioinformatic approaches to identify and test repurposed and repositioned drugs that modulate BMPR2 signaling. By testing compounds in vitro and in vivo models of HHT and PAH, our ultimate goal is to identify candidates that would be promising to move forward into clinical trials.

Our discoveries have led to the initiation of a phase II clinical trial to test the safety, tolerability and efficacy of low-dose FK506 in PAH at Stanford (http://www.clinicaltrials.gov NCT01647945) as well as three patents for repurposed and repositioned drugs for the treatment of PAH and HHT.

My laboratory values close collaboration of clinicians, translational as well as basic scientists to apply biological concepts to disease models, driven by the notion that we first need to understand processes in health and disease before we can intervene. The ultimate objective of the lab is to successfully realize bench-to-bedside research for our patients.

Clinical Trials


  • FK506 (Tacrolimus) in Pulmonary Arterial Hypertension Not Recruiting

    Mutations in bone morphogenetic protein receptor 2 (BMPR2) are present in \>80% of familial and \~20% of sporadic pulmonary arterial hypertension (PAH) patients. Furthermore dysfunctional BMP signaling is a general feature of pulmonary hypertension even in non-familial PAH. We therefore hypothesized that increasing BMP signaling might prevent and reverse the disease. We screened \> 3500 FDA approved drugs for their propensity to increase BMP signaling and found FK506 (Tacrolimus) to be a strong activator of BMP signaling. Tacrolimus restored normal function of pulmonary artery endothelial cells, prevented and reversed experimental PAH in mice and rats. Given that Tacrolimus is already FDA approved with a known side-effect profile, it is an ideal candidate drug to use in patients with pulmonary arterial hypertension. The aims of our trial are: 1. Establish the Safety of FK506 in patients with PAH. 2. Evaluate the Efficacy of FK506 in PAH 3. Identify ideal candidates for future FK506 phase III clinical trial.

    Stanford is currently not accepting patients for this trial. For more information, please contact Edda Spiekerkoetter, MD, 650-724-1493.

    View full details

2023-24 Courses


Stanford Advisees


All Publications


  • Cardiorenal Syndrome in Right Heart Failure Due to Pulmonary Arterial Hypertension-The Right Ventricle as a Therapeutic Target to Improve Renal Function. Cardiovascular drugs and therapy Ichimura, K., Gross, A., Mathew, R. O., Salman, L., Reddy, S., Spiekerkoetter, E., Sidhu, M. S. 2024

    Abstract

    Cardiorenal syndrome (CRS) due to right ventricular (RV) failure is a disease entity emerging as a key indicator of morbidity and mortality. The multifactorial aspects of CRS and the left-right ventricular interdependence complicate the link between RV failure and renal function. RV failure has a direct pathophysiological link to renal dysfunction by leading to systemic venous congestion in certain circumstances and low cardiac output in other situations, both leading to impaired renal perfusion. Indeed, renal dysfunction is known to be an independent predictor of mortality in patients with pulmonary arterial hypertension (PAH) and RV failure. Thus, it is important to further understand the interaction between the RV and renal function. RV adaptation is critical to long-term survival in patients with PAH. The RV is also known for its remarkable capacity to recover once the aggravating factor is addressed or mitigated. However, less is known about the renal potential for recovery following the resolution of chronic RV failure. In this review, we provide an overview of the intricate relationship between RV dysfunction and the subsequent development of CRS, with a particular emphasis on PAH. Additionally, we summarize potential RV-targeted therapies and their potential beneficial impact on renal function.

    View details for DOI 10.1007/s10557-024-07588-8

    View details for PubMedID 38847906

  • 3D Imaging Reveals Complex Microvascular Remodeling in the Right Ventricle in Pulmonary Hypertension. Circulation research Ichimura, K., Boehm, M., Andruska, A. M., Zhang, F., Schimmel, K., Bonham, S., Kabiri, A., Kheyfets, V. O., Ichimura, S., Reddy, S., Mao, Y., Zhang, T., Wang, G., Santana, E. J., Tian, X., Essafri, I., Vinh, R., Tian, W., Nicolls, M. R., Yajima, S., Shudo, Y., MacArthur, J. W., Woo, Y. J., Metzger, R. J., Spiekerkoetter, E. 2024

    Abstract

    Pathogenic concepts of right ventricular (RV) failure in pulmonary arterial hypertension focus on a critical loss of microvasculature. However, the methods underpinning prior studies did not take into account the 3-dimensional (3D) aspects of cardiac tissue, making accurate quantification difficult. We applied deep-tissue imaging to the pressure-overloaded RV to uncover the 3D properties of the microvascular network and determine whether deficient microvascular adaptation contributes to RV failure.Heart sections measuring 250-µm-thick were obtained from mice after pulmonary artery banding (PAB) or debanding PAB surgery and properties of the RV microvascular network were assessed using 3D imaging and quantification. Human heart tissues harvested at the time of transplantation from pulmonary arterial hypertension cases were compared with tissues from control cases with normal RV function.Longitudinal 3D assessment of PAB mouse hearts uncovered complex microvascular remodeling characterized by tortuous, shorter, thicker, highly branched vessels, and overall preserved microvascular density. This remodeling process was reversible in debanding PAB mice in which the RV function recovers over time. The remodeled microvasculature tightly wrapped around the hypertrophied cardiomyocytes to maintain a stable contact surface to cardiomyocytes as an adaptation to RV pressure overload, even in end-stage RV failure. However, microvasculature-cardiomyocyte contact was impaired in areas with interstitial fibrosis where cardiomyocytes displayed signs of hypoxia. Similar to PAB animals, microvascular density in the RV was preserved in patients with end-stage pulmonary arterial hypertension, and microvascular architectural changes appeared to vary by etiology, with patients with pulmonary veno-occlusive disease displaying a lack of microvascular complexity with uniformly short segments.3D deep tissue imaging of the failing RV in PAB mice, pulmonary hypertension rats, and patients with pulmonary arterial hypertension reveals complex microvascular changes to preserve the microvascular density and maintain a stable microvascular-cardiomyocyte contact. Our studies provide a novel framework to understand microvascular adaptation in the pressure-overloaded RV that focuses on cell-cell interaction and goes beyond the concept of capillary rarefaction.

    View details for DOI 10.1161/CIRCRESAHA.123.323546

    View details for PubMedID 38770652

  • Rat microbial biogeography and age-dependent lactic acid bacteria in healthy lungs. Lab animal Zhao, L., Cunningham, C. M., Andruska, A. M., Schimmel, K., Ali, M. K., Kim, D., Gu, S., Chang, J. L., Spiekerkoetter, E., Nicolls, M. R. 2024; 53 (2): 43-55

    Abstract

    The laboratory rat emerges as a useful tool for studying the interaction between the host and its microbiome. To advance principles relevant to the human microbiome, we systematically investigated and defined the multitissue microbial biogeography of healthy Fischer 344 rats across their lifespan. Microbial community profiling data were extracted and integrated with host transcriptomic data from the Sequencing Quality Control consortium. Unsupervised machine learning, correlation, taxonomic diversity and abundance analyses were performed to determine and characterize the rat microbial biogeography and identify four intertissue microbial heterogeneity patterns (P1-P4). We found that the 11 body habitats harbored a greater diversity of microbes than previously suspected. Lactic acid bacteria (LAB) abundance progressively declined in lungs from breastfed newborn to adolescence/adult, and was below detectable levels in elderly rats. Bioinformatics analyses indicate that the abundance of LAB may be modulated by the lung-immune axis. The presence and levels of LAB in lungs were further evaluated by PCR in two validation datasets. The lung, testes, thymus, kidney, adrenal and muscle niches were found to have age-dependent alterations in microbial abundance. The 357 microbial signatures were positively correlated with host genes in cell proliferation (P1), DNA damage repair (P2) and DNA transcription (P3). Our study established a link between the metabolic properties of LAB with lung microbiota maturation and development. Breastfeeding and environmental exposure influence microbiome composition and host health and longevity. The inferred rat microbial biogeography and pattern-specific microbial signatures could be useful for microbiome therapeutic approaches to human health and life quality enhancement.

    View details for DOI 10.1038/s41684-023-01322-x

    View details for PubMedID 38297075

    View details for PubMedCentralID PMC10834367

  • 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

  • Characterizing the Spatiotemporal Transcriptomic Response of the Right Ventricle to Acute Pressure Overload. International journal of molecular sciences Kheyfets, V. O., Kumar, S., Heerdt, P. M., Ichimura, K., Brown, R. D., Lucero, M., Essafri, I., Williams, S., Stenmark, K. R., Spiekerkoetter, E. 2023; 24 (11)

    Abstract

    This study analyzed microarray data of right ventricular (RV) tissue from rats exposed to pulmonary embolism to understand the initial dynamic transcriptional response to mechanical stress and compare it with experimental pulmonary hypertension (PH) models. The dataset included samples harvested from 55 rats at 11 different time points or RV locations. We performed principal component analysis (PCA) to explore clusters based on spatiotemporal gene expression. Relevant pathways were identified from fast gene set enrichment analysis using PCA coefficients. The RV transcriptomic signature was measured over several time points, ranging from hours to weeks after an acute increase in mechanical stress, and was found to be highly dependent on the severity of the initial insult. Pathways enriched in the RV outflow tracts of rats at 6 weeks after severe PE share many commonalities with experimental PH models, but the transcriptomic signature at the RV apex resembles control tissue. The severity of the initial pressure overload determines the trajectory of the transcriptomic response independent of the final afterload, but this depends on the location where the tissue is biopsied. Chronic RV pressure overload due to PH appears to progress toward similar transcriptomic endpoints.

    View details for DOI 10.3390/ijms24119746

    View details for PubMedID 37298696

  • Repetitive Schistosoma Exposure Causes Perivascular Lung Fibrosis and Persistent Pulmonary Hypertension. Clinical science (London, England : 1979) Kumar, R., Lee, M. H., Kassa, B., Fonseca Balladares, D. C., Mickael, C., Sanders, L., Andruska, A., Kumar, M., Spiekerkoetter, E., Bandeira, A., Stenmark, K. R., Tuder, R. M., Graham, B. B. 2023

    Abstract

    Pulmonary hypertension (PH) can occur as a complication of schistosomiasis. In humans, schistosomiasis-PH persists despite anti-helminthic therapy and parasite eradication. We hypothesized that persistent disease arises as a consequence of exposure repetition. Methods: Following intraperitoneal sensitization, mice were experimentally exposed to Schistosoma eggs by intravenous injection, either once or three times repeatedly. The phenotype was characterized by right heart catheterization and tissue analysis. Results: Following intraperitoneal sensitization, a single intravenous Schistosoma egg exposure resulted in a PH phenotype that peaked at 7 to 14 days, followed by spontaneous resolution. Three sequential exposures resulted in a persistent PH phenotype. Inflammatory cytokines were not significantly different between mice exposed to one or three egg doses, but there was an increase in perivascular fibrosis in those who received three egg doses. Significant perivascular fibrosis was also observed in autopsy specimens from patients who died of this condition. Conclusions: Repeatedly exposing mice to schistosomiasis causes a persistent PH phenotype, accompanied by perivascular fibrosis. Perivascular fibrosis may contribute to the persistent schistosomiasis-PH observed in humans with this disease.

    View details for DOI 10.1042/CS20220642

    View details for PubMedID 37014925

  • Novel left ventricular mechanical index in pulmonary arterial hypertension. Pulmonary circulation Ichimura, K., Santana, E. J., Kuznetsova, T., Cauwenberghs, N., Sabovčik, F., Chun, L., Francisco, N. L., Kheyfets, V. O., Salerno, M., Zamanian, R. T., Spiekerkoetter, E., Haddad, F. 2023; 13 (2): e12216

    Abstract

    Ventricular interdependence plays an important role in pulmonary arterial hypertension (PAH). It can decrease left ventricular (LV) longitudinal strain (LVLS) and lead to a leftward displacement ("transverse shortening") of the interventricular septum (sTS). For this study, we hypothesized the ratio of LVLS/sTS would be a sensitive marker of systolic ventricular interactions in PAH. In a cross-sectional cohort of patients with PAH (n = 57) and matched controls (n = 57), we quantified LVLS and septal TS in the amplitude and time domain. We then characterized LV phenotypes using upset plots, ventricular interactions using network analysis, and longitudinal analysis in a representative cohort of 45 patients. We also measured LV metrics in mice subjected to pulmonary arterial banding (PAB) using a 7 T magnetic resonance imaging at baseline, Week 1, and Week 7 post-PAB (N = 9). Patients with PAH had significantly reduced absolute LVLS (15.4 ± 3.4 vs. 20.1 ± 2.3%, p < 0.0001), higher sTS (53.0 ± 12.2 vs. 28.0 ± 6.2%, p < 0.0001) and lower LVLS/sTS (0.30 ± 0.09 vs. 0.75 ± 0.16, p < 0.0001) compared to controls. Reduced LVLS/sTS was observed in 89.5% of patients, while diastolic dysfunction, impaired LVLS (<16%), and LV atrophy were observed in 73.7%, 52.6%, and 15.8%, respectively. In the longitudinal cohort, changes in LVLS/sTS were closely associated with changes in N-terminal pro B-type natriuretic peptide (r = 0.73, p < 0.0001) as well as survival. Mice subjected to PAB showed significant RV systolic dysfunction and decreased LVLS/sTS compared to sham animals. We conclude that in PAH, LVLV/sTS is a simple ratio that can reflect ventricular systolic interactions.

    View details for DOI 10.1002/pul2.12216

    View details for PubMedID 37063750

    View details for PubMedCentralID PMC10103585

  • Decreasing ELK3 expression improves Bone Morphogenetic Protein Receptor 2 signaling and pulmonary vascular cell function in PAH. bioRxiv : the preprint server for biology Ali, M. K., Zhao, L., Perez, V. d., Nicolls, M. R., Spiekerkoetter, E. F. 2023

    Abstract

    ELK3 is upregulated in blood and pulmonary vascular cells of PAH patients and may play a significant role in PAH potentially through modulating BMPR2 signaling.

    View details for DOI 10.1101/2023.01.14.524023

    View details for PubMedID 36711443

    View details for PubMedCentralID PMC9882174

  • PTPN1 Deficiency Modulates BMPR2 Signaling and Induces Endothelial Dysfunction in Pulmonary Arterial Hypertension. Cells Ali, M. K., Tian, X., Zhao, L., Schimmel, K., Rhodes, C. J., Wilkins, M. R., Nicolls, M. R., Spiekerkoetter, E. F. 2023; 12 (2)

    Abstract

    Bone morphogenic protein receptor 2 (BMPR2) expression and signaling are impaired in pulmonary arterial hypertension (PAH). How BMPR2 signaling is decreased in PAH is poorly understood. Protein tyrosine phosphatases (PTPs) play important roles in vascular remodeling in PAH. To identify whether PTPs modify BMPR2 signaling, we used a siRNA-mediated high-throughput screening of 22,124 murine genes in mouse myoblastoma reporter cells using ID1 expression as readout for BMPR2 signaling. We further experimentally validated the top hit, PTPN1 (PTP1B), in healthy human pulmonary arterial endothelial cells (PAECs) either silenced by siRNA or exposed to hypoxia and confirmed its relevance to PAH by measuring PTPN1 levels in blood and PAECs collected from PAH patients. We identified PTPN1 as a novel regulator of BMPR2 signaling in PAECs, which is downregulated in the blood of PAH patients, and documented that downregulation of PTPN1 is linked to endothelial dysfunction in PAECs. These findings point to a potential involvement for PTPN1 in PAH and will aid in our understanding of the molecular mechanisms involved in the disease.

    View details for DOI 10.3390/cells12020316

    View details for PubMedID 36672250

  • The Human Respiratory Microbiome: Current Understandings and Future Directions. American journal of respiratory cell and molecular biology Zhao, L., Luo, J. L., Ali, M. K., Spiekerkoetter, E., Nicolls, M. R. 2022

    Abstract

    Microorganisms colonizing the human body. The lungs and respiratory tract, previously thought to be sterile, harbor diverse microbial communities and the genomes of bacteria (bacteriome), viruses (virome), and fungi (mycobiome). Recent advances in amplicon and shotgun metagenomic sequencing technologies, and data analyzing methods have greatly aided the identification and characterization of microbial populations from airways. The respiratory microbiome has been shown to play roles in human health and disease and is an area of rapidly emerging interest in pulmonary medicine. In this review we provide updated information in the field by focusing on four lung conditions including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), and idiopathic pulmonary fibrosis (IPF). We evaluate gut, oral, and upper airway microbiomes, and how they contribute to lower airway flora. The discussion is followed by a systematic review of the lower airway microbiome in health and disease. We conclude with promising research avenues and implications for evolving therapeutics.

    View details for DOI 10.1165/rcmb.2022-0208TR

    View details for PubMedID 36476129

  • The role of circular RNAs in pulmonary hypertension. The European respiratory journal Ali, M. K., Schimmel, K., Zhao, L., Chen, C. K., Dua, K., Nicolls, M. R., Spiekerkoetter, E. 2022

    Abstract

    Circular RNAs (CircRNAs) are endogenous, covalently circularized, non-protein-coding RNAs generated from back splicing. Most circRNAs are very stable, highly conserved, and expressed in a tissue-, cell- and developmental stage-specific manner. CircRNAs play a significant role in various biological processes, such as regulation of gene expression and protein translation via sponging of microRNAs and binding with RNA binding proteins. CircRNAs have become a topic of great interest in research due to their close link with the development of various diseases. Their high stability, conservation, and abundance in body fluids make them promising biomarkers for many diseases. A growing body of evidence suggests that aberrant expression of circRNAs and their targets plays a crucial role in pulmonary vascular remodeling and Group 1 pulmonary arterial hypertension (PAH) as well as other forms of pulmonary hypertension (PH) (Group 3 and 4). Here we discuss the roles and molecular mechanisms of circRNAs in the pathogenesis of pulmonary vascular remodeling and PH. We also highlight the therapeutic and biomarker potential of circRNAs in PH.

    View details for DOI 10.1183/13993003.00012-2022

    View details for PubMedID 35680145

  • Relationship between impaired BMP signalling and clinical risk factors at early-stage vascular injury in the preterm infant. Thorax Heydarian, M., Oak, P., Zhang, X., Kamgari, N., Kindt, A., Koschlig, M., Pritzke, T., Gonzalez-Rodriguez, E., Forster, K., Morty, R. E., Hafner, F., Hubener, C., Flemmer, A. W., Yildirim, A. O., Sudheendra, D., Tian, X., Petrera, A., Kirsten, H., Ahnert, P., Morrell, N., Desai, T. J., Sucre, J., Spiekerkoetter, E., Hilgendorff, A. 2022

    Abstract

    INTRODUCTION: Chronic lung disease, that is, bronchopulmonary dysplasia (BPD) is the most common complication in preterm infants and develops as a consequence of the misguided formation of the gas-exchange area undergoing prenatal and postnatal injury. Subsequent vascular disease and its progression into pulmonary arterial hypertension critically determines long-term outcome in the BPD infant but lacks identification of early, disease-defining changes.METHODS: We link impaired bone morphogenetic protein (BMP) signalling to the earliest onset of vascular pathology in the human preterm lung and delineate the specific effects of the most prevalent prenatal and postnatal clinical risk factors for lung injury mimicking clinically relevant conditions in a multilayered animal model using wild-type and transgenic neonatal mice.RESULTS: We demonstrate (1) the significant reduction in BMP receptor 2 (BMPR2) expression at the onset of vascular pathology in the lung of preterm infants, later mirrored by reduced plasma BMP protein levels in infants with developing BPD, (2) the rapid impairment (and persistent change) of BMPR2 signalling on postnatal exposure to hyperoxia and mechanical ventilation, aggravated by prenatal cigarette smoke in a preclinical mouse model and (3) a link to defective alveolar septation and matrix remodelling through platelet derived growth factor-receptor alpha deficiency. In a treatment approach, we partially reversed vascular pathology by BMPR2-targeted treatment with FK506 in vitro and in vivo.CONCLUSION: We identified impaired BMP signalling as a hallmark of early vascular disease in the injured neonatal lung while outlining its promising potential as a future biomarker or therapeutic target in this growing, high-risk patient population.

    View details for DOI 10.1136/thoraxjnl-2021-218083

    View details for PubMedID 35580897

  • Cardiac Fibrosis in the Pressure Overloaded Left and Right Ventricle as a Therapeutic Target. Frontiers in cardiovascular medicine Schimmel, K., Ichimura, K., Reddy, S., Haddad, F., Spiekerkoetter, E. 2022; 9: 886553

    Abstract

    Myocardial fibrosis is a remodeling process of the extracellular matrix (ECM) following cardiac stress. "Replacement fibrosis" is a term used to describe wound healing in the acute phase of an injury, such as myocardial infarction. In striking contrast, ECM remodeling following chronic pressure overload insidiously develops over time as "reactive fibrosis" leading to diffuse interstitial and perivascular collagen deposition that continuously perturbs the function of the left (L) or the right ventricle (RV). Examples for pressure-overload conditions resulting in reactive fibrosis in the LV are systemic hypertension or aortic stenosis, whereas pulmonary arterial hypertension (PAH) or congenital heart disease with right sided obstructive lesions such as pulmonary stenosis result in RV reactive fibrosis. In-depth phenotyping of cardiac fibrosis has made it increasingly clear that both forms, replacement and reactive fibrosis co-exist in various etiologies of heart failure. While the role of fibrosis in the pathogenesis of RV heart failure needs further assessment, reactive fibrosis in the LV is a pathological hallmark of adverse cardiac remodeling that is correlated with or potentially might even drive both development and progression of heart failure (HF). Further, LV reactive fibrosis predicts adverse outcome in various myocardial diseases and contributes to arrhythmias. The ability to effectively block pathological ECM remodeling of the LV is therefore an important medical need. At a cellular level, the cardiac fibroblast takes center stage in reactive fibrotic remodeling of the heart. Activation and proliferation of endogenous fibroblast populations are the major source of synthesis, secretion, and deposition of collagens in response to a variety of stimuli. Enzymes residing in the ECM are responsible for collagen maturation and cross-linking. Highly cross-linked type I collagen stiffens the ventricles and predominates over more elastic type III collagen in pressure-overloaded conditions. Research has attempted to identify pro-fibrotic drivers causing fibrotic remodeling. Single key factors such as Transforming Growth Factor β (TGFβ) have been described and subsequently targeted to test their usefulness in inhibiting fibrosis in cultured fibroblasts of the ventricles, and in animal models of cardiac fibrosis. More recently, modulation of phenotypic behaviors like inhibition of proliferating fibroblasts has emerged as a strategy to reduce pathogenic cardiac fibroblast numbers in the heart. Some studies targeting LV reactive fibrosis as outlined above have successfully led to improvements of cardiac structure and function in relevant animal models. For the RV, fibrosis research is needed to better understand the evolution and roles of fibrosis in RV failure. RV fibrosis is seen as an integral part of RV remodeling and presents at varying degrees in patients with PAH and animal models replicating the disease of RV afterload. The extent to which ECM remodeling impacts RV function and thus patient survival is less clear. In this review, we describe differences as well as common characteristics and key players in ECM remodeling of the LV vs. the RV in response to pressure overload. We review pre-clinical studies assessing the effect of anti-fibrotic drug candidates on LV and RV function and their premise for clinical testing. Finally, we discuss the mode of action, safety and efficacy of anti-fibrotic drugs currently tested for the treatment of left HF in clinical trials, which might guide development of new approaches to target right heart failure. We touch upon important considerations and knowledge gaps to be addressed for future clinical testing of anti-fibrotic cardiac therapies.

    View details for DOI 10.3389/fcvm.2022.886553

    View details for PubMedID 35600469

    View details for PubMedCentralID PMC9120363

  • Shunt-type plexiform lesions identified in the Sugen5416/Hypoxia rat model of pulmonary arterial hypertension using SPCT. The European respiratory journal van der Have, O., Westoo, C., Ahrne, F., Tian, X., Ichimura, K., Dreier, T., Norvik, C., Kumar, M. E., Spiekerkoetter, E., Tran-Lundmark, K. 2022

    View details for DOI 10.1183/13993003.02802-2021

    View details for PubMedID 35332070

  • Arteriovenous Malformations-Current Understanding of the Pathogenesis with Implications for Treatment. International journal of molecular sciences Schimmel, K., Ali, M. K., Tan, S. Y., Teng, J., Do, H. M., Steinberg, G. K., Stevenson, D. A., Spiekerkoetter, E. 2021; 22 (16)

    Abstract

    Arteriovenous malformations are a vascular anomaly typically present at birth, characterized by an abnormal connection between an artery and a vein (bypassing the capillaries). These high flow lesions can vary in size and location. Therapeutic approaches are limited, and AVMs can cause significant morbidity and mortality. Here, we describe our current understanding of the pathogenesis of arteriovenous malformations based on preclinical and clinical findings. We discuss past and present accomplishments and challenges in the field and identify research gaps that need to be filled for the successful development of therapeutic strategies in the future.

    View details for DOI 10.3390/ijms22169037

    View details for PubMedID 34445743

  • Role of Long Non-Coding RNAs in Pulmonary Arterial Hypertension. Cells Han, Y., Ali, M. K., Dua, K., Spiekerkoetter, E., Mao, Y. 2021; 10 (8)

    Abstract

    Pulmonary arterial hypertension (PAH) is a debilitating condition of the pulmonary circulatory system that occurs in patients of all ages and if untreated, eventually leads to right heart failure and death. Despite existing medical treatment options that improve survival and quality of life, the disease remains incurable. Thus, there is an urgent need to develop novel therapies to treat this disease. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play critical roles in pulmonary vascular remodeling and PAH. LncRNAs are implicated in pulmonary arterial endothelial dysfunction by modulating endothelial cell proliferation, angiogenesis, endothelial mesenchymal transition, and metabolism. LncRNAs are also involved in inducing different pulmonary arterial vascular smooth muscle cell phenotypes, such as cell proliferation, apoptosis, migration, regulation of the phenotypic switching, and cell cycle. LncRNAs are essential regulators of gene expression that affect various diseases at the chromatin, transcriptional, post-translational, and even post-translational levels. Here, we focus on the role of LncRNAs and their molecular mechanisms in the pathogenesis of PAH. We also discuss the current research challenge and potential biomarker and therapeutic potentials of lncRNAs in PAH.

    View details for DOI 10.3390/cells10081892

    View details for PubMedID 34440661

  • Pulmonary arterial banding in mice may be a suitable model for studies on ventricular mechanics in pediatric pulmonary arterial hypertension. Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance Dufva, M. J., Boehm, M., Ichimura, K., Truong, U., Qin, X., Tabakh, J., Hunter, K. S., Ivy, D., Spiekerkoetter, E., Kheyfets, V. O. 2021; 23 (1): 66

    Abstract

    BACKGROUND: The role of interventricular mechanics in pediatric pulmonary arterial hypertension (PAH) and its relation to right ventricular (RV) dysfunction has been largely overlooked. Here, we characterize the impact of maintained pressure overload in the RV-pulmonary artery (PA) axis on myocardial strain and left ventricular (LV) mechanics in pediatric PAH patients in comparison to a preclinical PA-banding (PAB) mouse model. We hypothesize that the PAB mouse model mimics important aspects of interventricular mechanics of pediatric PAH and may be beneficial as a surrogate model for some longitudinal and interventional studies not possible in children.METHODS: Balanced steady-state free precession (bSSFP) cardiovascular magnetic resonance (CMR) images of 18 PAH and 17 healthy (control) pediatric subjects were retrospectively analyzed using CMR feature-tracking (FT) software to compute measurements of myocardial strain. Furthermore, myocardial tagged-CMR images were also analyzed for each subject using harmonic phase flow analysis to derive LV torsion rate. Within 48h of CMR, PAH patients underwent right heart catheterization (RHC) for measurement of PA/RV pressures, and to compute RV end-systolic elastance (RV_Ees, a measure of load-independent contractility). Surgical PAB was performed on mice to induce RV pressure overload and myocardial remodeling. bSSFP-CMR, tagged CMR, and intra-cardiac catheterization were performed on 12 PAB and 9 control mice (Sham) 7 weeks after surgery with identical post-processing as in the aforementioned patient studies. RV_Ees was assessed via the single beat method.RESULTS: LV torsion rate was significantly reduced under hypertensive conditions in both PAB mice (p=0.004) and pediatric PAH patients (p<0.001). This decrease in LV torsion rate correlated significantly with a decrease in RV_Ees in PAB (r=0.91, p=0.05) and PAH subjects (r=0.51, p=0.04). In order to compare combined metrics of LV torsion rate and strain parameters principal component analysis (PCA) was used. PCA revealed grouping of PAH patients with PAB mice and control subjects with Sham mice. Similar to LV torsion rate, LV global peak circumferential, radial, and longitudinal strain were significantly (p<0.05) reduced under hypertensive conditions in both PAB mice and children with PAH.CONCLUSIONS: The PAB mouse model resembles PAH-associated myocardial mechanics and may provide a potential model to study mechanisms of RV/LV interdependency.

    View details for DOI 10.1186/s12968-021-00759-8

    View details for PubMedID 34078382

  • 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

  • Comparative analysis on the anti-inflammatory/immune effect of mesenchymal stem cell therapy for the treatment of pulmonary arterial hypertension. Scientific reports Oh, S. n., Jang, A. Y., Chae, S. n., Choi, S. n., Moon, J. n., Kim, M. n., Spiekerkoetter, E. n., Zamanian, R. T., Yang, P. C., Hwang, D. n., Byun, K. n., Chung, W. J. 2021; 11 (1): 2012

    Abstract

    Despite the advancement of targeted therapy for pulmonary arterial hypertension (PAH), poor prognosis remains a reality. Mesenchymal stem cells (MSCs) are one of the most clinically feasible alternative treatment options. We compared the treatment effects of adipose tissue (AD)-, bone marrow (BD)-, and umbilical cord blood (UCB)-derived MSCs in the rat monocrotaline-induced pulmonary hypertension (PH) model. The greatest improvement in the right ventricular function was observed in the UCB-MSCs treated group. The UCB-MSCs treated group also exhibited the greatest improvement in terms of the largest decrease in the medial wall thickness, perivascular fibrosis, and vascular cell proliferation, as well as the lowest levels of recruitment of innate and adaptive immune cells and associated inflammatory cytokines. Gene expression profiling of lung tissue confirmed that the UCB-MSCs treated group had the most notably attenuated immune and inflammatory profiles. Network analysis further revealed that the UCB-MSCs group had the greatest therapeutic effect in terms of the normalization of all three classical PAH pathways. The intravenous injection of the UCB-MSCs, compared with those of other MSCs, showed superior therapeutic effects in the PH model for the (1) right ventricular function, (2) vascular remodeling, (3) immune/inflammatory profiles, and (4) classical PAH pathways.

    View details for DOI 10.1038/s41598-021-81244-1

    View details for PubMedID 33479312

    View details for PubMedCentralID PMC7820276

  • Severe Pulmonary Arterial Hypertension is Characterized by Increased Neutrophil Elastase and Relative Elafin Deficiency. Chest Sweatt, A. J., Miyagawa, K., Rhodes, C. J., Taylor, S., Del Rosario, P. A., Hsi, A., Haddad, F., Spiekerkoetter, E., Bental-Roof, M., Bland, R. D., Swietlik, E. M., Gräf, S., Wilkins, M. R., Morrell, N. W., Nicolls, M. R., Rabinovitch, M., Zamanian, R. T. 2021

    Abstract

    Preclinical evidence implicates neutrophil elastase (NE) in PAH pathogenesis, and the NE inhibitor elafin is under early therapeutic investigation.Are circulating NE and elafin levels abnormal in PAH and associated with clinical severity?. In an observational Stanford University PAH cohort (N=249), plasma NE and elafin were measured in comparison to healthy controls (N=106) then related to clinical features and relevant ancillary biomarkers. Cox regression models were fitted with cubic spline functions to associate NE and elafin with survival. To validate prognostic relationships, we analyzed two United Kingdom cohorts (N=75, N=357). Mixed effects models evaluated NE and elafin changes during disease progression. Finally, we studied effects of NE/elafin balance on pulmonary artery endothelial cells (PAECs) from PAH patients.Relative to controls, patients had increased NE (205.1 [123.6-387.3] vs. 97.6 [74.4-126.6] ng/mL, P<0.0001) and decreased elafin (32.0 [15.3-59.1] vs. 45.5 [28.1-92.8] ng/mL, P<0.0001) independent of PAH subtype, illness duration, and therapies. Higher NE associated with worse symptom severity, shorter six-minute walk distance, higher NT-proBNP, greater right ventricular dysfunction, worse hemodynamics, increased circulating neutrophils, elevated cytokine levels, and lower blood BMPR2 expression. In Stanford patients, NE>168.5 ng/mL portended increased mortality risk after adjustment for known clinical predictors (HR 2.52, CI 1.36-4.65, P=0.003) or prognostic cytokines (HR 2.63, CI 1.42-4.87, P=0.001), and NE added incremental value to established PAH risk scores. Similar prognostic thresholds were identified in validation cohorts. Longitudinal NE changes tracked with clinical trends and outcomes. PAH-PAECs exhibited increased apoptosis and attenuated angiogenesis when exposed to NE at the level observed in patients' blood. Elafin rescued PAEC homeostasis, yet the required dose exceeded levels found in patients.NE is increased and elafin deficient across PAH subtypes. NE associates with disease severity and outcomes, and this target-specific biomarker could facilitate therapeutic development of elafin.

    View details for DOI 10.1016/j.chest.2021.06.028

    View details for PubMedID 34181952

  • Promising therapeutic approaches in pulmonary arterial hypertension. Current opinion in pharmacology Ali, M. K., Ichimura, K., Spiekerkoetter, E. 2021; 59: 127-139

    Abstract

    Pulmonary arterial hypertension (PAH) is a debilitating multifactorial disease characterized by progressive pulmonary vascular remodeling, elevated pulmonary arterial pressure, and pulmonary vascular resistance, resulting in right ventricular failure and subsequent death. Current available therapies do not reverse the disease, resulting in a persistent high morbidity and mortality. Thus, there is an urgent unmet medical need for novel effective therapies to better treat patients with PAH. Over the past few years, enthusiastic attempts have been made to identify novel effective therapies that address the essential roots of PAH with targeting key signaling pathways in both preclinical models and patients with PAH. This review aims to discuss the most emerging and promising therapeutic interventions in PAH pathogenesis.

    View details for DOI 10.1016/j.coph.2021.05.003

    View details for PubMedID 34217109

  • Novel Advances in Modifying BMPR2 Signaling in PAH. Genes Dannewitz Prosseda, S., Ali, M. K., Spiekerkoetter, E. 2020; 12 (1)

    Abstract

    Pulmonary Arterial Hypertension (PAH) is a disease of the pulmonary arteries, that is characterized by progressive narrowing of the pulmonary arterial lumen and increased pulmonary vascular resistance, ultimately leading to right ventricular dysfunction, heart failure and premature death. Current treatments mainly target pulmonary vasodilation and leave the progressive vascular remodeling unchecked resulting in persistent high morbidity and mortality in PAH even with treatment. Therefore, novel therapeutic strategies are urgently needed. Loss of function mutations of the Bone Morphogenetic Protein Receptor 2 (BMPR2) are the most common genetic factor in hereditary forms of PAH, suggesting that the BMPR2 pathway is fundamentally important in the pathogenesis. Dysfunctional BMPR2 signaling recapitulates the cellular abnormalities in PAH as well as the pathobiology in experimental pulmonary hypertension (PH). Approaches to restore BMPR2 signaling by increasing the expression of BMPR2 or its downstream signaling targets are currently actively explored as novel ways to prevent and improve experimental PH as well as PAH in patients. Here, we summarize existing as well as novel potential treatment strategies for PAH that activate the BMPR2 receptor pharmaceutically or genetically, increase the receptor availability at the cell surface, or reconstitute downstream BMPR2 signaling.

    View details for DOI 10.3390/genes12010008

    View details for PubMedID 33374819

  • Repurposing of medications for pulmonary arterial hypertension. Pulmonary circulation Toshner, M., Spiekerkoetter, E., Bogaard, H., Hansmann, G., Nikkho, S., Prins, K. W. 2020; 10 (4): 2045894020941494

    Abstract

    This manuscript on drug repurposing incorporates the broad experience of members of the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. Drug repurposing, use of a drug in a disease for which it was not originally developed, in pulmonary arterial hypertension has been a remarkable success story, as highlighted by positive large phase 3 clinical trials using epoprostenol, bosentan, iloprost, and sildenafil. Despite the availability of multiple therapies for pulmonary arterial hypertension, mortality rates have modestly changed. Moreover, pulmonary arterial hypertension patients are highly symptomatic and frequently end up on parental therapy and lung transplant waiting lists. Therefore, an unmet need for new treatments exists and drug repurposing may be an important avenue to address this problem.

    View details for DOI 10.1177/2045894020941494

    View details for PubMedID 33282182

  • The left ventricle undergoes biomechanical and gene expression changes in response to increased right ventricular pressure overload. Physiological reports Kheyfets, V. O., Dufva, M. J., Boehm, M., Tian, X., Qin, X., Tabakh, J. E., Truong, U., Ivy, D., Spiekerkoetter, E. 2020; 8 (9): e14347

    Abstract

    Pulmonary hypertension (PH) results in right ventricular (RV) pressure overload and eventual failure. Current research efforts have focused on the RV while overlooking the left ventricle (LV), which is responsible for mechanically assisting the RV during contraction. The objective of this study is to evaluate the biomechanical and gene expression changes occurring in the LV due to RV pressure overload in a mouse model. Nine male mice were divided into two groups: (a) pulmonary arterial banding (PAB, N=4) and (b) sham surgery (Sham, N=5). Tagged and steady-state free precision cardiac MRI was performed on each mouse at 1, 4, and 7weeks after surgery. At/week7, the mice were euthanized following right/left heart catheterization with RV/LV tissue harvested for histology and gene expression (using RT-PCR) studies. Compared to Sham mice, the PAB group revealed a significantly decreased LV and RV ejection fraction, and LV maximum torsion and torsion rate, within the first week after banding. In the PAB group, there was also a slight but significant increase in LV perivascular fibrosis, which suggests elevated myocardial stress. LV fibrosis was also accompanied with changes in gene expression in the hypertensive group, which was correlated with LV contractile mechanics. In fact, principal component (PC) analysis of LV gene expression effectively separated Sham and PAB mice along PC2. Changes in LV contractile mechanics were also significantly correlated with unfavorable changes in RV contractile mechanics, but a direct causal relationship was not established. In conclusion, a purely biomechanical insult of RV pressure overload resulted in biomechanical and transcriptional changes in both the RV and LV. Given that the RV relies on the LV for contractile energy assistance, considering the LV could provide prognostic and therapeutic targets for treating RV failure in PH.

    View details for DOI 10.14814/phy2.14347

    View details for PubMedID 32367677

  • The Hallmarks of Severe Pulmonary Arterial Hypertension: The Cancer Hypothesis - Ten years later. American journal of physiology. Lung cellular and molecular physiology Cool, C. D., Kuebler, W. M., Bogaard, H. J., Spiekerkoetter, E., Nicolls, M. R., Voelkel, N. F. 2020

    Abstract

    Severe forms of pulmonary arterial hypertension (PAH) are most frequently the consequence of a lumen-obliterating angiopathy. One pathobiological model is, that the initial pulmonary vascular endothelial cell injury and apoptosis is followed by the evolution of phenotypically altered, apoptosis-resistant, proliferating cells and an inflammatory vascular immune response. Although there may be a vasoconstrictive disease component, the increased pulmonary vascular shear stress in established PAH is caused largely by the vascular wall pathology. In this review, we revisit the "quasi-malignancy concept" of severe PAH and examine to what extent the hallmarks of PAH can be compared to the hallmarks of cancer. The cancer model of severe PAH, based on the growth of abnormal vascular and bone marrow-derived cells, may enable the emergence of novel cell-based PAH treatment strategies.

    View details for DOI 10.1152/ajplung.00476.2019

    View details for PubMedID 32023082

  • A Notch3-Marked Subpopulation of Vascular Smooth Muscle Cells is the Cell of Origin for Occlusive Pulmonary Vascular Lesions. Circulation Steffes, L. C., Froistad, A. A., Andruska, A. n., Boehm, M. n., McGlynn, M. n., Zhang, F. n., Zhang, W. n., Hou, D. n., Tian, X. n., Miquerol, L. n., Nadeau, K. n., Metzger, R. J., Spiekerkoetter, E. n., Kumar, M. E. 2020

    Abstract

    Background: Pulmonary arterial hypertension (PAH) is a fatal disease characterized by profound vascular remodeling in which pulmonary arteries narrow due to medial thickening and occlusion by neointimal lesions, resulting in elevated pulmonary vascular resistance and right heart failure. Therapies targeting the neointima would represent a significant advance in PAH treatment, however our understanding of the cellular events driving neointima formation, and the molecular pathways that control them, remains limited. Methods: We comprehensively map the stepwise remodeling of pulmonary arteries in a robust, chronic inflammatory mouse model of pulmonary hypertension. This model demonstrates pathologic features of the human disease, including increased right ventricular pressures, medial thickening, neointimal lesion formation, elastin breakdown, increased anastomosis within the bronchial circulation, and perivascular inflammation. Using genetic lineage tracing, clonal analysis, multiplexed in situ hybridization, immunostaining, deep confocal imaging and staged pharmacologic inhibition we define the cell behaviors underlying each stage of vascular remodeling and identify a pathway required for neointima formation. Results: Neointima arises from smooth muscle cells (SMCs) and not endothelium. Medial SMCs proliferate broadly to thicken the media, after which a small number of SMCs are selected to establish the neointima. These neointimal founder cells subsequently undergoing massive clonal expansion to form occlusive neointimal lesions. The normal pulmonary artery SMC population is heterogeneous and we identify a Notch3-marked minority subset of SMCs as the major neointimal cell of origin. Notch signaling is specifically required for the selection of neointimal founder cells, and Notch inhibition significantly improves pulmonary artery pressure in animals with pulmonary hypertension. Conclusions: This work describes the first nongenetically driven murine model of PH that generates robust and diffuse occlusive neointimal lesions across the pulmonary vascular bed and does so in a stereotyped timeframe. We uncover distinct cellular and molecular mechanisms underlying medial thickening and neointima formation and highlight novel transcriptional, behavioral and pathogenic heterogeneity within pulmonary artery SMCs. In this model, inflammation is sufficient to generate characteristic vascular pathologies and physiologic measures of human PAH. We hope that identifying the molecular cues regulating each stage of vascular remodeling will open new avenues for therapeutic advancements in the treatment of PAH.

    View details for DOI 10.1161/CIRCULATIONAHA.120.045750

    View details for PubMedID 32794408

  • Targeting BMPR2 Trafficking with Chaperones - An Important Step Towards Precision Medicine in Pulmonary Arterial Hypertension. American journal of respiratory cell and molecular biology Andruska, A. n., Ali, K. n., Spiekerkoetter, E. n. 2020

    View details for DOI 10.1165/rcmb.2020-0130ED

    View details for PubMedID 32339467

  • Targeted Proteomics of Right Heart Adaptation to Pulmonary Arterial Hypertension. The European respiratory journal Amsallem, M. n., Sweatt, A. J., Arthur Ataam, J. n., Guihaire, J. n., Lecerf, F. n., Lambert, M. n., Ghigna, M. R., Ali, M. K., Mao, Y. n., Fadel, E. n., Rabinovitch, M. n., de Jesus Perez, V. n., Spiekerkoetter, E. n., Mercier, O. n., Haddad, F. n., Zamanian, R. T. 2020

    Abstract

    No prior proteomic screening study has centered on the right ventricle (RV) in pulmonary arterial hypertension (PAH). This study investigates the circulating proteomic profile associated with right heart maladaptive phenotype (RHMP) in PAH.Plasma proteomic profiling was performed using multiplex immunoassay in 121 PAH patients (discovery cohort) and 76 patients (validation cohort). The association between proteomic markers and RHMP (defined by the Mayo right heart score [combining RV strain, New York Heart Association NYHA class and NT-proBNP] and Stanford score [RV end-systolic remodelling index, NYHA and NT-proBNP]) was assessed by partial least squares regression. Biomarkers expressions were measured in RV samples from PAH patients and controls, and pulmonary artery banding (PAB) mice.High levels of hepatic growth factor (HGF), stem cell growth factor beta, nerve growth factor and stromal derived factor-1 were associated with worse Mayo and Stanford scores independently from pulmonary resistance or pressure in both cohorts (the validation cohort had more severe disease features: lower cardiac index and higher NT-proBNP). In both cohorts, HGF added value to the REVEAL score in the prediction of death, transplant, or hospitalisation at 3 years. RV expression levels of HGF and its receptor c-Met were higher in end-stage PAH patients than controls, and in PAB mice than shams.High plasma HGF levels are associated with RHMP and predictive of 3-year clinical worsening. Both HGF and c-Met RV expression levels are increased in PAH. Assessing plasma HGF levels might identify patients at risk for heart failure who warrant closer follow-up and intensified therapy.

    View details for DOI 10.1183/13993003.02428-2020

    View details for PubMedID 33334941

  • Delineating the molecular and histological events that govern right ventricular recovery using a novel mouse model of PA de-banding. Cardiovascular research Boehm, M., Tian, X., Mao, Y., Ichimura, K., Dufva, M. J., Ali, K., Prosseda, S. D., Shi, Y., Kuramoto, K., Reddy, S., Kheyfets, V. O., Metzger, R. J., Spiekerkoetter, E. 2019

    Abstract

    AIMS: The temporal sequence of events underlying functional right ventricular (RV) recovery after improvement of pulmonary hypertension-associated pressure overload are unknown. We sought to establish a novel mouse model of gradual RV recovery from pressure overload and use it to delineate RV reverse-remodeling events.METHODS AND RESULTS: Surgical pulmonary artery banding (PAB) around a 26G needle induced RV dysfunction with increased RV pressures, reduced exercise capacity and caused liver congestion, hypertrophic, fibrotic and vascular myocardial remodeling within 5 weeks of chronic RV pressure overload in mice. Gradual reduction of the afterload burden through PA band absorption (de-PAB) - after RV dysfunction and structural remodeling were established - initiated recovery of RV function (cardiac output, exercise capacity) along with rapid normalization in RV hypertrophy (RV/LV+S, cardiomyocyte area) and RV pressures (RVSP). RV fibrotic (collagen, elastic fibers, vimentin+ fibroblasts) and vascular (capillary density) remodeling were equally reversible, however reversal occurred at a later time-point after de-PAB, when RV function was already completely restored. Microarray gene expression (ClariomS, Thermo Fisher) along with gene ontology analyses in RV tissues revealed growth factors, immune modulators and apoptosis mediators as major cellular components underlying functional RV recovery.CONCLUSIONS: We established a novel gradual de-PAB mouse model and used it to demonstrate that established pulmonary hypertension-associated RV dysfunction is fully reversible. Mechanistically, we link functional RV improvement to hypertrophic normalization that precedes fibrotic and vascular reverse-remodeling events.TRANSLATIONAL PERSPECTIVE: The right ventricle (RV) in pulmonary arterial hypertension possesses a remarkable ability to recover after lung transplantation. Yet, some transplant centers prefer a heart-lung instead of lung transplantation when the RV function is severely impaired because knowledge is lacking whether fibrotic and vascular myocardial remodeling are completely reversible once the increased afterload burden is relieved. We have developed a mouse model to study gradual unloading of the RV and identified key molecular components and the timing of RV reverse-remodeling events with the ultimate goal to understand the RV recovery process and identify ways how to support the RV during recovery.

    View details for DOI 10.1093/cvr/cvz310

    View details for PubMedID 31738411

  • Drug repositioning in pulmonary arterial hypertension: challenges and opportunities PULMONARY CIRCULATION Grinnan, D., Trankle, C., Andruska, A., Bloom, B., Spiekerkoetter, E. 2019; 9 (1)
  • EXPRESS: Drug Repositioning in Pulmonary Arterial Hypertension: Challenges and Opportunities. Pulmonary circulation Grinnan, D., Trankle, C., Andruska, A., Bloom, B., Spiekerkoetter, E. F. 2019: 2045894019832226

    View details for PubMedID 30729869

  • Hot topics in the mechanisms of pulmonary arterial hypertension disease: cancer-like pathobiology, the role of the adventitia, systemic involvement, and right ventricular failure. Pulmonary circulation Spiekerkoetter, E. n., Goncharova, E. A., Guignabert, C. n., Stenmark, K. n., Kwapiszewska, G. n., Rabinovitch, M. n., Voelkel, N. n., Bogaard, H. J., Graham, B. n., Pullamsetti, S. S., Kuebler, W. M. 2019; 9 (4): 2045894019889775

    Abstract

    In order to intervene appropriately and develop disease-modifying therapeutics for pulmonary arterial hypertension, it is crucial to understand the mechanisms of disease pathogenesis and progression. We herein discuss four topics of disease mechanisms that are currently highly debated, yet still unsolved, in the field of pulmonary arterial hypertension. Is pulmonary arterial hypertension a cancer-like disease? Does the adventitia play an important role in the initiation of pulmonary vascular remodeling? Is pulmonary arterial hypertension a systemic disease? Does capillary loss drive right ventricular failure? While pulmonary arterial hypertension does not replicate all features of cancer, anti-proliferative cancer therapeutics might still be beneficial in pulmonary arterial hypertension if monitored for safety and tolerability. It was recognized that the adventitia as a cell-rich compartment is important in the disease pathogenesis of pulmonary arterial hypertension and should be a therapeutic target, albeit the data are inconclusive as to whether the adventitia is involved in the initiation of neointima formation. There was agreement that systemic diseases can lead to pulmonary arterial hypertension and that pulmonary arterial hypertension can have systemic effects related to the advanced lung pathology, yet there was less agreement on whether idiopathic pulmonary arterial hypertension is a systemic disease per se. Despite acknowledging the limitations of exactly assessing vascular density in the right ventricle, it was recognized that the failing right ventricle may show inadequate vascular adaptation resulting in inadequate delivery of oxygen and other metabolites. Although the debate was not meant to result in a definite resolution of the specific arguments, it sparked ideas about how we might resolve the discrepancies by improving our disease modeling (rodent models, large-animal studies, studies of human cells, tissues, and organs) as well as standardization of the models. Novel experimental approaches, such as lineage tracing and better three-dimensional imaging of experimental as well as human lung and heart tissues, might unravel how different cells contribute to the disease pathology.

    View details for DOI 10.1177/2045894019889775

    View details for PubMedID 31798835

    View details for PubMedCentralID PMC6868582

  • FHIT, a Novel Modifier Gene in Pulmonary Arterial Hypertension AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Prosseda, S., Tian, X., Kuramoto, K., Boehm, M., Sudheendra, D., Miyagawa, K., Zhang, F., Solow-Cordero, D., Saldivar, J. C., Austin, E. D., Loyd, J. E., Wheeler, L., Andruska, A., Donato, M., Wang, L., Huebner, K., Metzger, R. J., Khatri, P., Spiekerkoetter, E. 2019; 199 (1): 83-98
  • EXPRESS: Myocardial Bridge - An Unrecognized Cause of Chest Pain in Pulmonary Arterial Hypertension. Pulmonary circulation Rajmohan, D. n., Sung, Y. K., Kudelko, K. n., Perez, V. i., Haddad, F. n., Tremmel, J. n., Schnittger, I. n., Zamanian, R. T., Spiekerkoetter, E. F. 2019: 2045894019860738

    View details for DOI 10.1177/2045894019860738

    View details for PubMedID 31187693

  • New and Emerging Therapies for Pulmonary Arterial Hypertension. Annual review of medicine Spiekerkoetter, E. n., Kawut, S. M., de Jesus Perez, V. A. 2019; 70: 45–59

    Abstract

    Pulmonary arterial hypertension (PAH) is a pulmonary vasculopathy that causes right ventricular dysfunction and exercise limitation and progresses to death. New findings from translational studies have suggested alternative pathways for treatment. These avenues include sex hormones, genetic abnormalities and DNA damage, elastase inhibition, metabolic dysfunction, cellular therapies, and anti-inflammatory approaches. Both novel and repurposed compounds with rationale from preclinical experimental models and human cells are now in clinical trials in patients with PAH. Findings from these studies will elucidate the pathobiology of PAH and may result in clinically important improvements in outcome.

    View details for PubMedID 30216732

  • Exome data clouds the pathogenicity of genetic variants in Pulmonary Arterial Hypertension MOLECULAR GENETICS & GENOMIC MEDICINE Abbasi, Y., Jabbari, J., Jabbari, R., Glinge, C., Izadyar, S., Spiekerkoetter, E., Zamanian, R. T., Carlsen, J., Tfelt-Hansen, J. 2018; 6 (5): 835–44

    Abstract

    We aimed to provide a set of previously reported PAH-associated missense and nonsense variants, and evaluate the pathogenicity of those variants.The Human Gene Mutation Database, PubMed, and Google Scholar were searched for previously reported PAH-associated genes and variants. Thereafter, both exome sequencing project and exome aggregation consortium as background population searched for previously reported PAH-associated missense and nonsense variants. The pathogenicity of previously reported PAH-associated missense variants evaluated by using four in silico prediction tools.In total, 14 PAH-associated genes and 180 missense and nonsense variants were gathered. The BMPR2, the most frequent reported gene, encompasses 135 of 180 missense and nonsense variants. The exome sequencing project comprised 9, and the exome aggregation consortium counted 25 of 180 PAH-associated missense and nonsense variants. The TOPBP1 and ENG genes are unlikely to be the monogenic cause of PAH pathogenesis based on allele frequency in background population and prediction analysis.This is the first evaluation of previously reported PAH-associated missense and nonsense variants. The BMPR2 identified as the major gene out of 14 PAH-associated genes. Based on findings, the ENG and TOPBP1 gene are not likely to be the monogenic cause of PAH.

    View details for PubMedID 30084161

  • Consequences of BMPR2 Deficiency in the Pulmonary Vasculature and Beyond: Contributions to Pulmonary Arterial Hypertension INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Andruska, A., Spiekerkoetter, E. 2018; 19 (9)
  • Consequences of BMPR2 Deficiency in the Pulmonary Vasculature and Beyond: Contributions to Pulmonary Arterial Hypertension. International journal of molecular sciences Andruska, A., Spiekerkoetter, E. 2018; 19 (9)

    Abstract

    Since its association with familial pulmonary arterial hypertension (PAH) in 2000, Bone Morphogenetic Protein Receptor II (BMPR2) and its related signaling pathway have become recognized as a key regulator of pulmonary vascular homeostasis. Herein, we define BMPR2 deficiency as either an inactivation of the receptor, decreased receptor expression, or an impairment of the receptor's downstream signaling pathway. Although traditionally the phenotypic consequences of BMPR2 deficiency in PAH have been thought to be limited to the pulmonary vasculature, there is evidence that abnormalities in BMPR2 signaling may have consequences in many other organ systems and cellular compartments. Revisiting how BMPR2 functions throughout health and disease in cells and organs beyond the lung vasculature may provide insight into the contribution of these organ systems to PAH pathogenesis as well as the potential systemic manifestation of PAH. Here we review our knowledge of the consequences of BMPR2 deficiency across multiple organ systems.

    View details for PubMedID 30149506

  • Fragile Histidine Triad (FHIT), a Novel Modifier Gene in Pulmonary Arterial Hypertension. American journal of respiratory and critical care medicine Dannewitz Prosseda, S., Tian, X., Kuramoto, K., Boehm, M., Sudheendra, D., Miyagawa, K., Zhang, F., Solow-Cordero, D., Saldivar, J. C., Austin, E. D., Loyd, J. E., Wheeler, L., Andruska, A., Donato, M., Wang, L., Huebner, K., Metzger, R. J., Khatri, P., Spiekerkoetter, E. 2018

    Abstract

    RATIONALE: Pulmonary arterial hypertension (PAH) is characterized by progressive narrowing of pulmonary arteries resulting in right heart failure and death. Bone Morphogenetic Protein Receptor type-2 (BMPR2) mutations account for most familial PAH (FPAH) forms while reduced BMPR2 is present in many idiopathic PAH (IPAH) forms, suggesting dysfunctional BMPR2 signaling to be a key feature of PAH. Modulating BMPR2 signaling is therapeutically promising, yet how BMPR2 is downregulated in PAH is unclear.OBJECTIVES: We intended to identify and pharmaceutically target BMPR2 modifier genes to improve PAH.METHODS: We combined siRNA High Throughput Screening (HTS) of >20,000 genes with a multi-cohort analysis of publicly available PAH RNA expression data to identify clinically relevant BMPR2-modifiers. After confirming gene dysregulation in PAH patient tissue, we determined the functional roles of BMPR2-modifiers in vitro and tested the repurposed drug Enzastaurin for its propensity to improve experimental PH.MEASUREMENTS AND MAIN RESULTS: We discovered Fragile Histidine Triad (FHIT) as a novel BMPR2-modifier. BMPR2 and FHIT expression were reduced in PAH patients. FHIT reductions were associated with endothelial and smooth muscle cell dysfunction, rescued by Enzastaurin through a dual mechanism: upregulation of FHIT as well as miR17-5 repression. Fhit-/- mice had exaggerated hypoxic PH and failed to recover in normoxia. Enzastaurin reversed PH in the Sugen5416/Hypoxia/Normoxia rat model, by improving Right Ventricular Systolic Pressure (RVSP), RV hypertrophy, cardiac fibrosis and vascular remodeling.CONCLUSIONS: This study highlights the importance of the novel BMPR2 modifier FHIT in PH and the clinical value of the repurposed drug Enzastaurin as a potential novel therapeutic strategy to improve PAH.

    View details for PubMedID 30107138

  • Update in Pulmonary Vascular Disease 2016 and 2017 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Brittain, E. L., Thennapan, T., Maron, B. A., Chan, S. Y., Austin, E. D., Spiekerkoetter, E., Bogaard, H. J., Guignabert, C., Paulin, R., Machado, R. F., Yu, P. B. 2018; 198 (1): 13–23

    View details for PubMedID 29533671

    View details for PubMedCentralID PMC6034126

  • New and Emerging Therapies for Pulmonary Arterial Hypertension Annual Reviews in medicine Spiekerkoetter, E., Kawut, S., de Jesus Perez, V. 2018
  • A Pro - Con debate: Current Controversies in PAH Pathogenesis at the American Thoracic Society International Meeting in 2017. American journal of physiology. Lung cellular and molecular physiology Kuebler, W. M., Nicolls, M. R., Olschewski, A. n., Abe, K. n., Rabinovitch, M. n., Stewart, D. J., Chan, S. Y., Morrell, N. W., Archer, S. L., Spiekerkoetter, E. n. 2018

    Abstract

    The following review summarizes the pro-con debate about current controversies regarding the pathogenesis of pulmonary arterial hypertension (PAH) that took place at the American Thoracic Society Conference in May 2017. Leaders in the field of PAH research discussed the importance of the immune system, the role of hemodynamic stress and endothelial apoptosis as well as bone morphogenetic protein receptor 2 (BMPR2) signaling in PAH pathogenesis. While this summary does not intend to resolve obvious conflicts in opinion, we hope that the presented arguments entice further discussions and draw a new generation of enthusiastic researchers into this vibrant field of science to bridge existing gaps for a better understanding and therapy of this fatal disease.

    View details for PubMedID 29877097

  • Career Development of Young Physician-Scientists in the Cardiovascular Sciences: Perspective and Advice From the Early Career Committee of the Cardiopulmonary, Critical Care, and Resuscitation Council of the American Heart Association. Circulation research Agarwal, S. n., Spiekerkoetter, E. n., Austin, E. D., de Jesus Perez, V. n., Dezfulian, C. n., Maron, B. A., Ryan, J. J., Starks, M. A., Yu, P. B., Bonnet, S. n., Perman, S. M. 2018; 122 (10): 1330–33

    View details for PubMedID 29748361

  • Randomised placebo-controlled safety and tolerability trial of FK506 (tacrolimus) for pulmonary arterial hypertension EUROPEAN RESPIRATORY JOURNAL Spiekerkoetter, E., Sung, Y. K., Sudheendra, D., Scott, V., Del Rosario, P., Bill, M., Haddad, F., Long-Boyle, J., Hedlin, H., Zamanian, R. T. 2017; 50 (3)

    Abstract

    Pulmonary arterial hypertension (PAH) is a devastating disease characterised by occlusive pulmonary vasculopathy. Activation of bone morphogenetic protein receptor 2 (BMPR2) signalling by FK506 (tacrolimus) reverses occlusive vasculopathy in rodent PAH models. Here, we determined the safety and tolerability of low-level FK506 therapy in stable PAH patients.We performed a randomised, double-blind, placebo-controlled, 16-week, single-centre, phase IIa trial in PAH patients with New York Heart Association functional class II/III symptoms using three FK506 target levels (<2, 2-3 and 3-5 ng·mL-1). 23 patients were randomised and 20 patients completed the trial.FK506 was generally well tolerated, with nausea/diarrhoea being the most commonly reported adverse event and no observation of line infections in patients on intravenous prostacyclin therapy. PAH patients had significantly lower BMPR2 expression in peripheral blood mononuclear cells versus healthy controls (n=13; p=0.005), which improved after FK506 treatment. While we observed that some patients responded with a pronounced increase in BMPR2 expression as well as improvement in 6-min walk distance, and serological and echocardiographic parameters of heart failure, these changes were not significant.Low-level FK506 is well tolerated and increases BMPR2 in subsets of PAH patients. These results support the study of FK506 in a phase IIb efficacy trial.

    View details for PubMedID 28893866

  • 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

  • Low-Dose FK506 (Tacrolimus) in End-Stage Pulmonary Arterial Hypertension. American journal of respiratory and critical care medicine Spiekerkoetter, E., Sung, Y. K., Sudheendra, D., Bill, M., Aldred, M. A., van de Veerdonk, M. C., Vonk Noordegraaf, A., Long-Boyle, J., Dash, R., Yang, P. C., Lawrie, A., Swift, A. J., Rabinovitch, M., Zamanian, R. T. 2015; 192 (2): 254-257

    View details for DOI 10.1164/rccm.201411-2061LE

    View details for PubMedID 26177174

  • Elafin Reverses Pulmonary Hypertension via Caveolin-1-Dependent Bone Morphogenetic Protein Signaling AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Nickel, N. P., Spiekerkoetter, E., Gu, M., Li, C. G., Li, H., Kaschwich, M., Diebold, I., Hennigs, J. K., Kim, K., Miyagawa, K., Wang, L., Cao, A., Sa, S., Jiang, X., Stockstill, R. W., Nicolls, M. R., Zamanian, R. T., Bland, R. D., Rabinovitch, M. 2015; 191 (11): 1273-1286

    Abstract

    Pulmonary arterial hypertension is characterized by endothelial cell dysfunction, impaired BMPR2 signaling, and increased elastase activity. Synthetic elastase inhibitors reverse experimental pulmonary hypertension but cause hepatotoxicity in clinical studies. The endogenous elastase inhibitor elafin attenuates the development of hypoxic pulmonary hypertension in mice, but its potential to improve endothelial cell function and BMPR2 signaling, and to reverse severe experimental pulmonary hypertension or vascular pathology in the human disease was unknown.To assess elafin-mediated regression of pulmonary vascular pathology in rats with pulmonary hypertension induced by VEGF receptor blockade and hypoxia (Sugen/Hypoxia), and in lung explants from pulmonary hypertension patients. To determine if elafin amplifies BMPR2 signaling in pulmonary artery endothelial cells from controls and patients, and to elucidate the underlying mechanism. Methods, Measurements and Main Results: In Sugen/Hypoxia rats, elafin reduced elastase activity and reversed pulmonary hypertension, judged by regression of right ventricular systolic pressure and hypertrophy and pulmonary artery occlusive changes. Elafin improved endothelial function by increasing apelin, a product of BMPR2 signaling. Elafin induced apoptosis in human pulmonary arterial smooth muscle cells and in lung organ culture elafin decreased neointimal lesions. In normal and patient pulmonary artery endothelial cells, elafin enhanced survival and promoted angiogenesis by increasing pSMAD dependent and independent BMPR2 signaling. This was linked mechanistically to augmented interaction of BMPR2 with caveolin-1 via elafin-mediated stabilization of caveolin-1 on endothelial surfaces.Elafin reverses obliterative changes in rat and human pulmonary arteries via elastase inhibition and caveolin-1 dependent amplification of BMPR2 signaling.

    View details for DOI 10.1164/rccm.201412-2291OC

    View details for Web of Science ID 000356105000014

    View details for PubMedID 25853696

  • Hedgehog Signaling Restrains Bladder Cancer Progression by Eliciting Stromal Production of Urothelial Differentiation Factors CANCER CELL Shin, K., Lim, A., Zhao, C., Sahoo, D., Pan, Y., Spiekerkoetter, E., Liao, J. C., Beachy, P. A. 2014; 26 (4): 521-533

    Abstract

    Hedgehog (Hh) pathway inhibitors are clinically effective in treatment of basal cell carcinoma and medulloblastoma, but fail therapeutically or accelerate progression in treatment of endodermally derived colon and pancreatic cancers. In bladder, another organ of endodermal origin, we find that despite its initial presence in the cancer cell of origin Sonic hedgehog (Shh) expression is invariably lost during progression to invasive urothelial carcinoma. Genetic blockade of stromal response to Shh furthermore dramatically accelerates progression and decreases survival time. This cancer-restraining effect of Hh pathway activity is associated with stromal expression of BMP signals, which stimulate urothelial differentiation. Progression is dramatically reduced by pharmacological activation of BMP pathway activity with low-dose FK506, suggesting an approach to management of human bladder cancer.

    View details for DOI 10.1016/j.cce11.2014.09.001

    View details for Web of Science ID 000343343800012

  • Targeting the Wnt signaling pathways in pulmonary arterial hypertension. Drug discovery today de Jesus Perez, V., Yuan, K., Alastalo, T., Spiekerkoetter, E., Rabinovitch, M. 2014; 19 (8): 1270-1276

    Abstract

    Pulmonary arterial hypertension (PAH) is a life-threatening disorder that is associated with elevated pulmonary pressures and right heart failure resulting from progressive loss and thickening of small pulmonary arteries. Despite their ability to improve symptoms, current therapies fail to prevent disease progression, leaving lung transplantation as the only therapy in end-stage PAH. To overcome the limitations of current therapies, there is an active search for disease-modifying agents capable of altering the natural history of, and improving clinical outcomes in, PAH. The Wnt signaling pathways have emerged as attractive treatment targets in PAH given their role in the preservation of pulmonary vascular homeostasis and the recent development of Wnt-specific compounds and biological therapies capable of modulating pathway activity. In this review, we summarize the literature describing the role of Wnt signaling in the pulmonary circulation and discuss promising advances in the field of Wnt therapeutics that could lead to novel clinical therapies capable of preventing and/or reversing pulmonary vascular pathology in patients with this devastating disease.

    View details for DOI 10.1016/j.drudis.2014.06.014

    View details for PubMedID 24955837

  • Current Clinical Management of Pulmonary Arterial Hypertension CIRCULATION RESEARCH Zamanian, R. T., Kudelko, K. T., Sung, Y. K., Perez, V. D., Liu, J., Spiekerkoetter, E. 2014; 115 (1): 131-147

    Abstract

    During the past 2 decades, there has been a tremendous evolution in the evaluation and care of patients with pulmonary arterial hypertension (PAH). The introduction of targeted PAH therapy consisting of prostacyclin and its analogs, endothelin antagonists, phosphodiesterase-5 inhibitors, and now a soluble guanylate cyclase activator have increased therapeutic options and potentially reduced morbidity and mortality; yet, none of the current therapies have been curative. Current clinical management of PAH has become more complex given the focus on early diagnosis, an increased number of available therapeutics within each mechanistic class, and the emergence of clinically challenging scenarios such as perioperative care. Efforts to standardize the clinical care of patients with PAH have led to the formation of multidisciplinary PAH tertiary care programs that strive to offer medical care based on peer-reviewed evidence-based, and expert consensus guidelines. Furthermore, these tertiary PAH centers often support clinical and basic science research programs to gain novel insights into the pathogenesis of PAH with the goal to improve the clinical management of this devastating disease. In this article, we discuss the clinical approach and management of PAH from the perspective of a single US-based academic institution. We provide an overview of currently available clinical guidelines and offer some insight into how we approach current controversies in clinical management of certain patient subsets. We conclude with an overview of our program structure and a perspective on research and the role of a tertiary PAH center in contributing new knowledge to the field.

    View details for DOI 10.1161/CIRCRESAHA.115.303827

    View details for Web of Science ID 000337738900016

  • Current clinical management of pulmonary arterial hypertension. Circulation research Zamanian, R. T., Kudelko, K. T., Sung, Y. K., de Jesus Perez, V., Liu, J., Spiekerkoetter, E. 2014; 115 (1): 131-47

    Abstract

    During the past 2 decades, there has been a tremendous evolution in the evaluation and care of patients with pulmonary arterial hypertension (PAH). The introduction of targeted PAH therapy consisting of prostacyclin and its analogs, endothelin antagonists, phosphodiesterase-5 inhibitors, and now a soluble guanylate cyclase activator have increased therapeutic options and potentially reduced morbidity and mortality; yet, none of the current therapies have been curative. Current clinical management of PAH has become more complex given the focus on early diagnosis, an increased number of available therapeutics within each mechanistic class, and the emergence of clinically challenging scenarios such as perioperative care. Efforts to standardize the clinical care of patients with PAH have led to the formation of multidisciplinary PAH tertiary care programs that strive to offer medical care based on peer-reviewed evidence-based, and expert consensus guidelines. Furthermore, these tertiary PAH centers often support clinical and basic science research programs to gain novel insights into the pathogenesis of PAH with the goal to improve the clinical management of this devastating disease. In this article, we discuss the clinical approach and management of PAH from the perspective of a single US-based academic institution. We provide an overview of currently available clinical guidelines and offer some insight into how we approach current controversies in clinical management of certain patient subsets. We conclude with an overview of our program structure and a perspective on research and the role of a tertiary PAH center in contributing new knowledge to the field.

    View details for DOI 10.1161/CIRCRESAHA.115.303827

    View details for PubMedID 24951763

  • Reduced BMPR2 expression induces GM-CSF translation and macrophage recruitment in humans and mice to exacerbate pulmonary hypertension. journal of experimental medicine Sawada, H., Saito, T., Nickel, N. P., Alastalo, T., Glotzbach, J. P., Chan, R., Haghighat, L., Fuchs, G., Januszyk, M., Cao, A., Lai, Y., Perez, V. d., Kim, Y., Wang, L., Chen, P., Spiekerkoetter, E., Mitani, Y., Gurtner, G. C., Sarnow, P., Rabinovitch, M. 2014; 211 (2): 263-280

    Abstract

    Idiopathic pulmonary arterial hypertension (PAH [IPAH]) is an insidious and potentially fatal disease linked to a mutation or reduced expression of bone morphogenetic protein receptor 2 (BMPR2). Because intravascular inflammatory cells are recruited in IPAH pathogenesis, we hypothesized that reduced BMPR2 enhances production of the potent chemokine granulocyte macrophage colony-stimulating factor (GM-CSF) in response to an inflammatory perturbation. When human pulmonary artery (PA) endothelial cells deficient in BMPR2 were stimulated with tumor necrosis factor (TNF), a twofold increase in GM-CSF was observed and related to enhanced messenger RNA (mRNA) translation. The mechanism was associated with disruption of stress granule formation. Specifically, loss of BMPR2 induced prolonged phospho-p38 mitogen-activated protein kinase (MAPK) in response to TNF, and this increased GADD34-PP1 phosphatase activity, dephosphorylating eukaryotic translation initiation factor (eIF2α), and derepressing GM-CSF mRNA translation. Lungs from IPAH patients versus unused donor controls revealed heightened PA expression of GM-CSF co-distributing with increased TNF and expanded populations of hematopoietic and endothelial GM-CSF receptor α (GM-CSFRα)-positive cells. Moreover, a 3-wk infusion of GM-CSF in mice increased hypoxia-induced PAH, in association with increased perivascular macrophages and muscularized distal arteries, whereas blockade of GM-CSF repressed these features. Thus, reduced BMPR2 can subvert a stress granule response, heighten GM-CSF mRNA translation, increase inflammatory cell recruitment, and exacerbate PAH.

    View details for DOI 10.1084/jem.20111741

    View details for PubMedID 24446489

  • 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

  • A case of recurrent pericardial constriction presenting with severe pulmonary hypertension. Pulmonary circulation Brunner, N. W., Ramachandran, K., Kudelko, K. T., Sung, Y. K., Spiekerkoetter, E., Yang, P. C., Zamanian, R. T., Perez, V. d. 2013; 3 (2): 436-439

    Abstract

    Chronic constrictive pericarditis (CP) is a relatively rare condition in which the pericardium becomes fibrotic and noncompliant, eventually resulting in heart failure due to impaired ventricular filling. The only curative treatment is pericardiectomy. Classically, CP does not usually cause severe pulmonary hypertension. When attempting to differentiate CP from restrictive cardiomyopathy, the presence of severely elevated pulmonary arterial pressure is used as a diagnostic criterion ruling against CP. We present a case of proven recurrent pericardial constriction following pericardiectomy presenting with severe pulmonary hypertension.

    View details for DOI 10.4103/2045-8932.114780

    View details for PubMedID 24015347

  • A case of recurrent pericardial constriction presenting with severe pulmonary hypertension PULMONARY CIRCULATION Brunner, N. W., Ramachandran, K., Kudelko, K. T., Sung, Y. K., Spiekerkoetter, E., Yang, P. C., Zamanian, R. T., Perez, V. d. 2013; 3 (2): 436-439

    Abstract

    Chronic constrictive pericarditis (CP) is a relatively rare condition in which the pericardium becomes fibrotic and noncompliant, eventually resulting in heart failure due to impaired ventricular filling. The only curative treatment is pericardiectomy. Classically, CP does not usually cause severe pulmonary hypertension. When attempting to differentiate CP from restrictive cardiomyopathy, the presence of severely elevated pulmonary arterial pressure is used as a diagnostic criterion ruling against CP. We present a case of proven recurrent pericardial constriction following pericardiectomy presenting with severe pulmonary hypertension.

    View details for DOI 10.4103/2045-8932.114780

    View details for Web of Science ID 000209981500020

    View details for PubMedCentralID PMC3757841

  • 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

  • Safety and efficacy of transition from systemic prostanoids to inhaled treprostinil in pulmonary arterial hypertension. American journal of cardiology de Jesus Perez, V. A., Rosenzweig, E., Rubin, L. J., Poch, D., Bajwa, A., Park, M., Jain, M., Bourge, R. C., Kudelko, K., Spiekerkoetter, E., Liu, J., Hsi, A., Zamanian, R. T. 2012; 110 (10): 1546-1550

    Abstract

    Pulmonary arterial hypertension (PAH) is a disease characterized by increased pulmonary pressures and chronic right heart failure. Therapies for moderate and severe PAH include subcutaneous (SQ) and intravenous (IV) prostanoids that improve symptoms and quality of life. However, treatment compliance can be limited by severe side effects and complications related to methods of drug administration. Inhaled prostanoids, which offer the advantage of direct delivery of the drug to the pulmonary circulation without need for invasive approaches, may serve as an alternative for patients unable to tolerate SQ/IV therapy. In this retrospective cohort study we collected clinical, hemodynamic, and functional data from 18 clinically stable patients with World Health Organization group I PAH seen in 6 large national PAH centers before and after transitioning to inhaled treprostinil from IV/SQ prostanoids. Before transition 15 patients had been receiving IV or SQ treprostinil (mean dose 73 ng/kg/min) and 3 patients had been on IV epoprostenol (mean dose 10 ng/kg/min) for an average duration of 113 ± 80 months. Although most patients who transitioned to inhaled treprostinil demonstrated no statistically significant worsening of hemodynamics or 6-minute walk distance, a minority demonstrated worsening of New York Heart Association functional class over a 7-month period. In conclusion, although transition of patients from IV/SQ prostanoids to inhaled treprostinil appears to be well tolerated in clinically stable patients, they should remain closely monitored for signs of clinical decompensation.

    View details for DOI 10.1016/j.amjcard.2012.07.012

    View details for PubMedID 22853986

  • Safety and Efficacy of Transition from Systemic Prostanoids to Inhaled Treprostinil in Pulmonary Arterial Hypertension AMERICAN JOURNAL OF CARDIOLOGY Perez, V. A., Rosenzweig, E., Rubin, L. J., Poch, D., Bajwa, A., Park, M., Jain, M., Bourge, R. C., Kudelko, K., Spiekerkoetter, E., Liu, J., Hsi, A., Zamanian, R. T. 2012; 110 (10): 1546-1550

    Abstract

    Pulmonary arterial hypertension (PAH) is a disease characterized by increased pulmonary pressures and chronic right heart failure. Therapies for moderate and severe PAH include subcutaneous (SQ) and intravenous (IV) prostanoids that improve symptoms and quality of life. However, treatment compliance can be limited by severe side effects and complications related to methods of drug administration. Inhaled prostanoids, which offer the advantage of direct delivery of the drug to the pulmonary circulation without need for invasive approaches, may serve as an alternative for patients unable to tolerate SQ/IV therapy. In this retrospective cohort study we collected clinical, hemodynamic, and functional data from 18 clinically stable patients with World Health Organization group I PAH seen in 6 large national PAH centers before and after transitioning to inhaled treprostinil from IV/SQ prostanoids. Before transition 15 patients had been receiving IV or SQ treprostinil (mean dose 73 ng/kg/min) and 3 patients had been on IV epoprostenol (mean dose 10 ng/kg/min) for an average duration of 113 ± 80 months. Although most patients who transitioned to inhaled treprostinil demonstrated no statistically significant worsening of hemodynamics or 6-minute walk distance, a minority demonstrated worsening of New York Heart Association functional class over a 7-month period. In conclusion, although transition of patients from IV/SQ prostanoids to inhaled treprostinil appears to be well tolerated in clinically stable patients, they should remain closely monitored for signs of clinical decompensation.

    View details for DOI 10.1016/j.amjcard.2012.07.012

    View details for Web of Science ID 000311523900026

  • Reduced BMPR2 Increases GM-CSF mRNA Translation by Inhibiting eIF2 alpha Mediated Stress Granule Formation and Propensity to Pulmonary Vascular Disease Scientific Sessions of the American-Heart-Association/Resuscitation Science Symposium Sawada, H., Alastalo, T., Glotzbach, J. P., Chan, R., Fuchs, G., Januszyk, M., Lai, Y., Perez, V. D., Saito, T., Spiekerkoetter, E., Wang, L., Gurtner, G. C., Sarnow, P., Rabinovitch, M. LIPPINCOTT WILLIAMS & WILKINS. 2011
  • Neutrophil Elastase Is Produced by Pulmonary Artery Smooth Muscle Cells and Is Linked to Neointimal Lesions AMERICAN JOURNAL OF PATHOLOGY Kim, Y., Haghighat, L., Spiekerkoetter, E., Sawada, H., Alvira, C. M., Wang, L., Acharya, S., Rodriguez-Colon, G., Orton, A., Zhao, M., Rabinovitch, M. 2011; 179 (3): 1560-1572

    Abstract

    Previously, we reported that murine gammaherpesvirus-68 (M1-MHV-68) induces pulmonary artery (PA) neointimal lesions in S100A4-overexpressing, but not in wild-type (C57), mice. Lesions were associated with heightened lung elastase activity and PA elastin degradation. We now investigate a direct relationship between elastase and PA neointimal lesions, the nature and source of the enzyme, and its presence in clinical disease. We found an association exists between the percentage of PAs with neointimal lesions and elastin fragmentation in S100A4 mice 6 months after viral infection. Confocal microscopy documented the heightened susceptibility of S100A4 versus C57 PA elastin to degradation by elastase. A transient increase in lung elastase activity occurs in S100A4 mice, 7 days after M1-MHV-68, unrelated to inflammation or viral load and before neointimal lesions. Administration of recombinant elafin, an elastase-specific inhibitor, ameliorates early increases in serine elastase and attenuates later development of neointimal lesions. Neutrophils are the source of elevated elastase (NE) in the S100A4 lung, and NE mRNA and protein levels are greater in PA smooth muscle cells (SMC) from S100A4 mice than from C57 mice. Furthermore, elevated NE is observed in cultured PA SMC from idiopathic PA hypertension versus that in control lungs and localizes to neointimal lesions. Thus, PA SMC produce NE, and heightened production and activity of NE is linked to experimental and clinical pulmonary vascular disease.

    View details for DOI 10.1016/j.ajpath.2011.05.051

    View details for PubMedID 21763677

  • BMP promotes motility and represses growth of smooth muscle cells by activation of tandem Wnt pathways JOURNAL OF CELL BIOLOGY Perez, V. A., Ali, Z., Alastalo, T., Ikeno, F., Sawada, H., Lai, Y., Kleisli, T., Spiekerkoetter, E., Qu, X., Rubinos, L. H., Ashley, E., Amieva, M., Dedhar, S., Rabinovitch, M. 2011; 192 (1): 171-188

    Abstract

    We present a novel cell-signaling paradigm in which bone morphogenetic protein 2 (BMP-2) consecutively and interdependently activates the wingless (Wnt)-β-catenin (βC) and Wnt-planar cell polarity (PCP) signaling pathways to facilitate vascular smooth muscle motility while simultaneously suppressing growth. We show that BMP-2, in a phospho-Akt-dependent manner, induces βC transcriptional activity to produce fibronectin, which then activates integrin-linked kinase 1 (ILK-1) via α4-integrins. ILK-1 then induces the Wnt-PCP pathway by binding a proline-rich motif in disheveled (Dvl) and consequently activating RhoA-Rac1-mediated motility. Transfection of a Dvl mutant that binds βC without activating RhoA-Rac1 not only prevents BMP-2-mediated vascular smooth muscle cell motility but promotes proliferation in association with persistent βC activity. Interfering with the Dvl-dependent Wnt-PCP activation in a murine stented aortic graft injury model promotes extensive neointima formation, as shown by optical coherence tomography and histopathology. We speculate that, in response to injury, factors that subvert BMP-2-mediated tandem activation of Wnt-βC and Wnt-PCP pathways contribute to obliterative vascular disease in both the systemic and pulmonary circulations.

    View details for DOI 10.1083/jcb.201008060

    View details for PubMedID 21220513

  • S100A4 and Bone Morphogenetic Protein-2 Codependently Induce Vascular Smooth Muscle Cell Migration via Phospho-Extracellular Signal-Regulated Kinase and Chloride Intracellular Channel 4 CIRCULATION RESEARCH Spiekerkoetter, E., Guignabert, C., Perez, V. D., Alastalo, T., Powers, J. M., Wang, L., Lawrie, A., Ambartsumian, N., Schmidt, A., Berryman, M., Ashley, R. H., Rabinovitch, M. 2009; 105 (7): 639-U37

    Abstract

    S100A4/Mts1 is implicated in motility of human pulmonary artery smooth muscle cells (hPASMCs), through an interaction with the RAGE (receptor for advanced glycation end products).We hypothesized that S100A4/Mts1-mediated hPASMC motility might be enhanced by loss of function of bone morphogenetic protein (BMP) receptor (BMPR)II, observed in pulmonary arterial hypertension.Both S100A4/Mts1 (500 ng/mL) and BMP-2 (10 ng/mL) induce migration of hPASMCs in a novel codependent manner, in that the response to either ligand is lost with anti-RAGE or BMPRII short interference (si)RNA. Phosphorylation of extracellular signal-regulated kinase is induced by both ligands and is required for motility by inducing matrix metalloproteinase 2 activity, but phospho-extracellular signal-regulated kinase 1/2 is blocked by anti-RAGE and not by BMPRII short interference RNA. In contrast, BMPRII short interference RNA, but not anti-RAGE, reduces expression of intracellular chloride channel (CLIC)4, a scaffolding molecule necessary for motility in response to S100A4/Mts1 or BMP-2. Reduced CLIC4 expression does not interfere with S100A4/Mts1 internalization or its interaction with myosin heavy chain IIA, but does alter alignment of myosin heavy chain IIA and actin filaments creating the appearance of vacuoles. This abnormality is associated with reduced peripheral distribution and/or delayed activation of RhoA and Rac1, small GTPases required for retraction and extension of lamellipodia in motile cells.Our studies demonstrate how a single ligand (BMP-2 or S100A4/Mts1) can recruit multiple cell surface receptors to relay signals that coordinate events culminating in a functional response, ie, cell motility. We speculate that this carefully controlled process limits signals from multiple ligands, but could be subverted in disease.

    View details for DOI 10.1161/CIRCRESAHA.109.205120

    View details for Web of Science ID 000270150800006

    View details for PubMedID 19713532

    View details for PubMedCentralID PMC2818124

  • Reactivation of gamma HV68 induces neointimal lesions in pulmonary arteries of S100A4/Mts1-overexpressing mice in association with degradation of elastin AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY Spiekerkoetter, E., Alvira, C. M., Kim, Y., Bruneau, A., Pricola, K. L., Wang, L., Ambartsumian, N., Rabinovitch, M. 2008; 294 (2): L276-L289

    Abstract

    S100A4/Mts-overexpressing mice have thick elastic laminae and mild pulmonary arterial hypertension (PAH), and the occasional older mouse develops occlusive neointimal lesions and perivascular inflammation. We hypothesized that a vasculotropic virus could induce neointimal lesions in the S100A4/Mts1 mouse by facilitating breakdown of elastin and migration and proliferation of smooth muscle cells. To test this hypothesis, we infected S100A4/Mts1 mice with gammaherpesvirus 68 (gammaHV68). We observed, 6 mo after gammaHV68 [4 x 10(3) plaque-forming units (PFU)], perivascular inflammation in 10/15 S100A4/Mts1 mice and occlusive neointimal formation in 3/10 mice, accompanied by striking degradation of elastin. We then compared the early response after high-dose gammaHV68 (4 x 10(6) PFU) in C57Bl/6 and S100A4/Mts1 mice. In S100A4/Mts1 mice only, significant PAH, muscularization of distal vessels, and elastase activity were observed 6 wk after gammaHV68. These features resolved by 3 mo without neointimal formation. We therefore infected mice with the M1-gammaHV68 strain that reactivates from latency with higher efficiency and observed neointimal lesions at 3 mo in 2/5 C57Bl/6 (5-9% of vessels) and in 5/5 S100A4/Mts1 mice (13-40% of vessels) accompanied by mild PAH, heightened lung elastase activity, and intravascular viral expression. This suggested that enhanced generation of elastin peptides in S100A4/Mts1 mice may promote increased viral entry in the vessel wall. Using S100A4/Mts1 PA organ culture, we showed, in response to elastase activity, heightened production of elastin peptides associated with invasion of inflammatory cells and intravascular viral antigen. We therefore propose that early viral access to the vessel wall may be a critical determinant of the extent of vascular pathology following reactivation.

    View details for DOI 10.1152/ajplung.00414.2007

    View details for PubMedID 18083765

  • Experience with inhaled iloprost and bosentan in portopulmonary hypertension EUROPEAN RESPIRATORY JOURNAL Hoeper, M. M., Seyfarth, H. J., Hoefflken, G., Wirtz, H., Spielkerkoetter, E., Pletz, M. W., Welte, T., Halank, M. 2007; 30 (6): 1096-1102

    Abstract

    Novel treatments, such as prostanoids or endothelin receptor antagonists, have been introduced for various forms of pulmonary arterial hypertension, but the long-term effects of these treatments on portopulmonary hypertension (PPHT) are unknown. In a retrospective analysis, the present authors assessed the safety and efficacy of inhaled iloprost, a prostacyclin analogue, and bosentan, an endothelin receptor antagonist, in patients with PPHT. In total, 31 consecutive patients with Child class A or B cirrhosis and severe PPHT were treated for up to 3 yrs with either inhaled iloprost (n = 13) or bosentan (n = 18), and the effects on exercise capacity, haemodynamics and survival were evaluated. In the iloprost group, the survival rates at 1, 2 and 3 yrs were 77, 62 and 46%, respectively. In the bosentan group, the respective survival rates were 94, 89 and 89%. Event-free survival rates, i.e. survival without transplantation, right heart failure or clinical worsening requiring the introduction of a new treatment for pulmonary hypertension, was also significantly better in the bosentan group. Bosentan had significantly better effects than inhaled iloprost on exercise capacity, as determined by the 6-min walk test, as well as on haemodynamics. Both treatments proved to be safe, especially in regards of liver function. In the present series of patients with well-preserved liver function and severe portopulmonary hypertension, treatment with both inhaled iloprost and bosentan appeared to be safe. Patients treated with bosentan had higher survival rates, but prospective controlled studies are required to confirm these findings.

    View details for DOI 10.1183/09031936.00032407

    View details for Web of Science ID 000251521800012

    View details for PubMedID 17652314

  • Bone morphogenetic protein 2 (BMP 2) and wingless 3a (Wnt 3a) stimulate human pulmonary artery smooth muscle cell (hPASMC) motility via activation of a Rho and Rac dependent non-canonical Wnt pathway de Jesus Perez, V. A., Hansmann, G., Spiekerkoetter, E., Rabinovitch, M. LIPPINCOTT WILLIAMS & WILKINS. 2006: 82
  • Mts1/S100A4 stimulates human pulmonary artery smooth muscle cell migration through multiple signaling pathways 47th Annual Thomas L Petty Aspen Lung Conference Spiekerkoetter, E., Lawrie, A., Merklinger, S., Ambartsumian, N., Lukanidin, D., Schmidt, A. A., Rabbiovitch, M. AMER COLL CHEST PHYSICIANS. 2005: 577S–577S

    View details for Web of Science ID 000234371400021

    View details for PubMedID 16373840

  • Goal-oriented treatment and combination therapy for pulmonary arterial hypertension EUROPEAN RESPIRATORY JOURNAL Hoeper, M. M., Markevych, I., Spiekerkoetter, E., Welte, T., Niedermeyer, J. 2005; 26 (5): 858-863

    Abstract

    Combination therapy may improve outcome in patients with severe pulmonary arterial hypertension (PAH). PAH patients were treated according to a goal-oriented therapeutic strategy. Patients who did not reach the treatment goals with monotherapy received combination treatment according to a predefined strategy, including bosentan, sildenafil and inhaled iloprost. Intravenous iloprost and lung transplantation were reserved for treatment failures. End points were overall survival, transplantation-free survival, and survival free from transplantation and intravenous prostanoid treatment. Between January 2002 and December 2004, 123 consecutive patients with PAH were treated according to the novel approach. Survival at 1, 2 and 3 yrs was 93.0, 83.1 and 79.9%, respectively, which was significantly better than the survival of a historical control group, as well as the expected survival. Compared to the historical control group, the use of combination treatment also significantly improved the combined end point of death, lung transplantation and need for intravenous iloprost treatment. In conclusion, a therapeutic approach utilising combinations of bosentan, sildenafil and inhaled iloprost in conjunction with a goal-oriented treatment strategy provides acceptable long-term results in patients with severe pulmonary arterial hypertension, and reduces the need for intravenous prostaglandin treatment and lung transplantation.

    View details for DOI 10.1183/09031936.05.00075305

    View details for Web of Science ID 000233224400017

    View details for PubMedID 16264047

  • Chloride intracellular channel 4 (CLIC4), a novel downstream target of bone morphogenetic protein receptor II (BMPR-II) in human pulmonary artery smooth muscle cell (PASMC) migration 78th Annual Scientific Session of the American-Heart-Association Spiekerkoetter, E., Wang, L. L., Zamanian, R., Ambartsumian, N., Schmidt, A. M., Lukanidin, E., RABINOVITCH, M. LIPPINCOTT WILLIAMS & WILKINS. 2005: U210–U210
  • 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

  • Interdependent serotonin transporter and receptor pathways regulate S100A4/Mts1, a gene associated with pulmonary vascular disease CIRCULATION RESEARCH Lawrie, A., Spiekerkoetter, E., Martinez, E. C., Ambartsumian, N., Sheward, W. J., MacLean, M. R., Harmar, A. J., Schmidt, A. M., Lukanidin, E., Rabinovitch, M. 2005; 97 (3): 227-235

    Abstract

    Heightened expression of the S100 calcium-binding protein, S100A4/Mts1, is observed in pulmonary vascular disease. Loss of serotonin (5-hydroxytryptamine [5-HT]) receptors or of the serotonin transporter (SERT) attenuates pulmonary hypertension in animals, and polymorphisms causing gain of SERT function are linked to clinical pulmonary vascular disease. Because 5-HT induces release of S100beta, we investigated the codependence of 5-HT receptors and SERT in regulating S100A4/Mts1 in human pulmonary artery smooth muscle cells (hPA-SMC). 5-HT elevated S100A4/Mts1 mRNA levels and increased S100A4/Mts1 protein in hPA-SMC lysates and culture media. S100A4/Mts1 in the culture media stimulated proliferation and migration of hPA-SMC in a manner dependent on the receptor for advanced glycation end products. Treatment with SB224289 (selective antagonist of 5-HT1B), fluoxetine (SERT inhibitor), SERT RNA-interference, and iproniazid (monoamine oxidase-A inhibitor), blocked 5-HT-induced S100A4/Mts1. 5-HT signaling mediated phosphorylation (p) of extracellular signal-regulated kinase 1/2 (pERK1/2), but pERK1/2 nuclear translocation depended on SERT, monoamine oxidase activity, and reactive oxygen species. Nuclear translocation of pERK1/2 was required for pGATA-4-mediated transcription of S100A4/Mts1. These data provide evidence for a mechanistic link between the 5-HT pathway and S100A4/Mts1 in pulmonary hypertension and explain how the 5-HT1B receptor and SERT are codependent in regulating S100A4/Mts1.

    View details for DOI 10.1161/01.RES.0000176025.57706.1e

    View details for Web of Science ID 000230995100006

    View details for PubMedID 16002749

  • Combined environmental stimuli, d-fenfluramine and hypoxia, induce severe pulmonary hypertension in S100A4/Mts1-overexpressing mice that are prone to develop pulmonary vascular obliterative disease (PVOD) Spiekerkoetter, E., Merklinger, S. L., Lawrie, A., Ambartsumian, N., Lukanidin, E., Rabinovitch, M. LIPPINCOTT WILLIAMS & WILKINS. 2004: 19
  • Bosentan treatment in patients with primary pulmonary hypertension receiving nonparenteral prostanoids EUROPEAN RESPIRATORY JOURNAL Hoeper, M. M., Taha, N., Bekjarova, A., Gatzke, R., Spiekerkoetter, E. 2003; 22 (2): 330-334

    Abstract

    Primary pulmonary hypertension (PPH) is a life-threatening disease. Nonparenteral prostanoids, i.e. aerosolised iloprost or oral beraprost sodium show beneficial therapeutic effects but are not sufficiently active in all patients with this devastating disease. The purpose of the present study was to determine whether the endothelin-receptor antagonist bosentan is safe and effective in patients with PPH already receiving nonparenteral prostanoids. The effect of bosentan as add-on medication was studied in 20 patients with PPH, who received either inhaled iloprost (n=9) or oral beraprost (n=11) for a median period of 16+/-13 months, by means of the 6-min walk test and cardiopulmonary exercise testing. After 3 months of administration of bosentan in addition to prostanoids, the walking distance in the 6-min walk test increased by 58+/-43 m. Cardiopulmonary exercise testing revealed an increase in maximal oxygen consumption from 11.0+/-2.3 to 13.8+/-3.6 mL x kg(-1) x min(-1) accompanied by significant improvements in anaerobic threshold, oxygen pulse and minute ventilation/carbon dioxide production slope. Peak systolic blood pressure increased from 120+/-17 to 139+/-21 mmHg. Combination treatment was well tolerated by all patients. It is concluded that the addition of the endothelin-receptor antagonist bosentan to inhaled iloprost or oral beraprost therapy appears to be safe for patients with primary pulmonary hypertension, resulting in a marked increase in exercise capacity. Therefore, rigorous studies should address whether combination treatment is more effective than either therapeutic intervention alone.

    View details for DOI 10.1183/09031936.03.00008003

    View details for Web of Science ID 000184865400026

    View details for PubMedID 12952269

  • Effects of inhaled salbutamol in primary pulmonary hypertension EUROPEAN RESPIRATORY JOURNAL Spiekerkoetter, E., Fabel, H., Hoeper, M. M. 2002; 20 (3): 524-528

    Abstract

    Although lung function is grossly normal in patients with primary pulmonary hypertension (PPH), mild-to-moderate peripheral airflow obstruction can be found in the majority of patients with this disease. Therefore, beta2-agonists may affect pulmonary function, blood gases and haemodynamics in patients with PPH. Pulmonary function testing, blood gas measurements and right heart catheterisation was performed in 22 patients with PPH and the acute effects of inhaled salbutamol (0.2 mg) were measured. Salbutamol caused an increase in the forced expiratory volume in one second (FEV1) from 2446+/-704 to 2550+/-776 mL. The mean expiratory flow at 50% of the vital capacity (MEF50) rose from 58+/-17 to 66+/-21% pred. The pulmonary artery pressures remained unchanged after inhalation of salbutamol, but the cardiac output increased significantly from 3.9+/-1.4 to 4.2+/-1.4 L x min(-1) accompanied by significant increases in stroke volume and mixed venous oxygen saturation as well as a significant decrease in pulmonary vascular resistance. The arterial oxygen tension rose from 9+/-2.4 kPa (68+/-18 mmHg) at baseline to 9.7+/-2.8 kPa (73+/-21 mmHg) after inhalation of salbutamol, the alveolo-arterial oxygen gradient values improved from 6+/-2.5 kPa (45+/-19 mmHg) to 5.1+/-2.9 kPa (38+/-22 mmHg), respectively. Inhaled salbutamol has beneficial acute effects on pulmonary function, blood gases and haemodynamics in patients with primary pulmonary hypertension.

    View details for DOI 10.1183/09031936.02.02572001

    View details for Web of Science ID 000178187100005

    View details for PubMedID 12358324

  • Intravenous iloprost for treatment failure of aerosolised iloprost in pulmonary arterial hypertension EUROPEAN RESPIRATORY JOURNAL Hoeper, M. M., Spiekerkoetter, E., Westerkamp, V., Gatzke, R., Fabel, H. 2002; 20 (2): 339-343

    Abstract

    Treatment with aerosolised iloprost, a prostacyclin analogue, has beneficial effects in patients with pulmonary arterial hypertension (PAH). It is unclear if patients, whose clinical condition deteriorates under treatment with aerosolised iloprost, benefit from switching to continuous intravenous iloprost. The current authors report on 16 patients with severe PAH who received continuous intravenous iloprost after primary or secondary failure of treatment with aerosolised iloprost. Determinants of efficacy were survival, New York Heart Association (NYHA) class, and walking distance in the 6-min walk test. Of 93 patients with PAH treated with aerosolised iloprost, 16 required switching to intravenous iloprost for clinical deterioration. These patients had severe right heart failure with a cardiac index of 1.6+/-0.2 L x min(-1) x m(-2) and a mixed-venous oxygen saturation of 52+/-6%. Five of these patients showed no improvement and eventually died. Three patients had further deterioration in NYHA class and exercise capacity; two of them underwent lung transplantation; the third patient is still alive. Eight patients showed marked clinical improvement; one underwent lung transplantation and the others are currently alive and stable. In the latter group of patients, the walking distance in the 6-min walk test increased from 205+/-94 to 329+/-59 m. It was not possible to identify clinical or haemodynamic factors that would predict whether switching from inhaled to intravenous iloprost would have a beneficial effect. In patients with pulmonary arterial hypertension who deteriorated while being treated with aerosolised iloprost, switching to continuous intravenous iloprost caused substantial improvement in exercise capacity in eight of 16 patients but could not prevent progression of pulmonary hypertension in the remaining eight patients. Since it was impossible to predict the individual effects of this approach, intravenous prostaglandin treatment should be considered in pulmonary arterial hypertension patients who deteriorate while receiving iloprost aerosol.

    View details for DOI 10.1183/09031936.02.02462001

    View details for Web of Science ID 000177641400017

    View details for PubMedID 12212965

  • [Long-term treatment of primary pulmonary hypertension with inhaled iloprost]. Pneumologie (Stuttgart, Germany) Hoeper, M. M., Schwarze, M., Ehlerding, S., Adler-Schuermeyer, A., Spiekerkoetter, E., Niedermeyer, J., Hamm, M., Fabel, H. 2001; 55 (1): 38-43

    Abstract

    Continuous intravenous infusion of prostacyclin is an effective treatment for primary pulmonary hypertension. This approach, however, requires the insertion of a permanent central venous catheter with the potential risk of serious complications. Recently, administration of aerosolized iloprost, a stable prostacyclin analogue, has been introduced as an alternative therapy for severe pulmonary hypertension.We evaluated the effects of treatment with aerosolized iloprost over a one-year period on exercise capacity and hemodynamic variables in patients with primary pulmonary hypertension.Twenty-four patients with primary pulmonary hypertension received aerosolized iloprost at a cumulative daily dose of 100 to 150 micrograms for at least one year. The mean (+/- SD) walking distance in the 6-min-walk test increased from 278 +/- 96 meters at base line to 363 +/- 135 meters after 12 months (P < 0.0001). During the same period, the mean pulmonary artery pressure declined from 59 +/- 10 mmHg to 52 +/- 15 mmHg (P = 0.006), the cardiac output increased from 3.8 +/- 1.4 l/min to 4.4 +/- 1.3 l/min (P = 0.02), and the pulmonary vascular resistance declined from 1.205 +/- 467 dynes.s.cm-5 to 925 +/- 469 dynes.s.cm-5 (P = 0.0003). Treatment was generally well tolerated and except for mild coughing, minor headache and jaw pain in some patients, no side effects occurred.Long-term treatment with aerosolized iloprost is safe and has sustained effects on exercise capacity and pulmonary hemodynamics in patients with primary pulmonary hypertension.

    View details for PubMedID 11236355

  • Long-term treatment of primary pulmonary hypertension with aerosolized iloprost, a prostacyclin analogue. NEW ENGLAND JOURNAL OF MEDICINE Hoeper, M. M., Schwarze, M., Ehlerding, S., Adler-Schuermeyer, A., Spiekerkoetter, E., Niedermeyer, J., Hamm, M., Fabel, H. 2000; 342 (25): 1866-1870

    Abstract

    Continuous intravenous infusion of epoprostenol (prostacyclin) is an effective treatment for primary pulmonary hypertension. This approach requires the insertion of a permanent central venous catheter, with the associated risk of serious complications. Recently, aerosolized iloprost, a stable prostacyclin analogue, has been introduced as an alternative therapy for severe pulmonary hypertension.We evaluated the effects of aerosolized iloprost on exercise capacity and hemodynamic variables over a one-year period in patients with primary pulmonary hypertension.Twenty-four patients with primary pulmonary hypertension received aerosolized iloprost at a daily dose of 100 or 150 microg for at least one year. The mean (+/-SD) distance covered in the six-minute walk test increased from 278+/-96 m at base line to 363+/-135 m after 12 months (P<0.001). During the same period, the mean pulmonary arterial pressure before the inhalation of iloprost declined from 59+/-10 mm Hg to 52+/-15 mm Hg (P=0.006), cardiac output increased from 3.8+/-1.4 liters per minute to 4.4+/-1.3 liters per minute (P=0.02), and pulmonary vascular resistance declined from 1205+/-467 dyn x sec x cm(-5) to 925+/-469 dyn x sec x cm(-5) (P<0.001). The treatment was generally well tolerated, except for mild coughing, minor headache, and jaw pain in some patients.Long-term treatment with aerosolized iloprost is safe and has sustained effects on exercise capacity and pulmonary hemodynamics in patients with primary pulmonary hypertension.

    View details for Web of Science ID 000087704700003

    View details for PubMedID 10861321

  • Prevalence of malignancies after lung transplantation International Congress on Immunosuppression Spiekerkoetter, E., Krug, N., Hoeper, M., Wiebe, K., Hamm, M., Harringer, W., Haverich, A., Fabel, H. ELSEVIER SCIENCE INC. 1998: 1523–24

    View details for Web of Science ID 000074150800245

    View details for PubMedID 9636620