Clinical Focus


  • Vascular Medicine
  • Cardiovascular Disease

Academic Appointments


All Publications


  • Temporal Effects of Plozasiran on Lipids and Lipoproteins in Persistent Chylomicronemia. Circulation Watts, G. F., Hegele, R. A., Rosenson, R. S., Goldberg, I. J., Gallo, A., Mertens, A., Baass, A., Zhou, R., Muhsin, M., Hellawell, J., Gaudet, D., Leeper, N. J. 2024

    View details for DOI 10.1161/CIRCULATIONAHA.124.072860

    View details for PubMedID 39549263

  • Pro-efferocytic nanotherapies reduce vascular inflammation without inducing anemia in a large animal model of atherosclerosis. Nature communications Bamezai, S., Zhang, Y., Kumari, M., Lotfi, M., Alsaigh, T., Luo, L., Kumar, G. S., Wang, F., Ye, J., Puri, M., Manchanda, R., Paluri, S., Adkar, S. S., Kojima, Y., Ingelsson, A., Bell, C. F., Lopez, N. G., Fu, C., Choi, R. B., Miller, Z., Barrios, L., Walsh, S., Ahmad, F., Maegdefessel, L., Smith, B. R., Leeper, N. J. 2024; 15 (1): 8034

    Abstract

    Atherosclerosis is an inflammatory disorder responsible for cardiovascular disease. Reactivation of efferocytosis, the phagocytic removal of cells by macrophages, has emerged as a translational target for atherosclerosis. Systemic blockade of the key 'don't-eat-me' molecule, CD47, triggers the engulfment of apoptotic vascular tissue and potently reduces plaque burden. However, it also induces red blood cell clearance, leading to anemia. To overcome this, we previously developed a macrophage-specific nanotherapy loaded with a chemical inhibitor that promotes efferocytosis. Because it was found to be safe and effective in murine studies, we aimed to advance our nanoparticle into a porcine model of atherosclerosis. Here, we demonstrate that production can be scaled without impairing nanoparticle function. At an early stage of disease, we find our nanotherapy reduces apoptotic cell accumulation and inflammation in the atherosclerotic lesion. Notably, this therapy does not induce anemia, highlighting the translational potential of targeted macrophage checkpoint inhibitors.

    View details for DOI 10.1038/s41467-024-52005-1

    View details for PubMedID 39271657

    View details for PubMedCentralID 4826466

  • Plozasiran for Managing Persistent Chylomicronemia and Pancreatitis Risk. The New England journal of medicine Watts, G. F., Rosenson, R. S., Hegele, R. A., Goldberg, I. J., Gallo, A., Mertens, A., Baass, A., Zhou, R., Muhsin, M., Hellawell, J., Leeper, N. J., Gaudet, D. 2024

    Abstract

    Persistent chylomicronemia is a genetic recessive disorder that is classically caused by familial chylomicronemia syndrome (FCS), but it also has multifactorial causes. The disorder is associated with the risk of recurrent acute pancreatitis. Plozasiran is a small interfering RNA that reduces hepatic production of apolipoprotein C-III and circulating triglycerides.In a phase 3 trial, we randomly assigned 75 patients with persistent chylomicronemia (with or without a genetic diagnosis) to receive subcutaneous plozasiran (25 mg or 50 mg) or placebo every 3 months for 12 months. The primary end point was the median percent change from baseline in the fasting triglyceride level at 10 months. Key secondary end points were the percent change in the fasting triglyceride level from baseline to the mean of values at 10 months and 12 months, changes in the fasting apolipoprotein C-III level from baseline to 10 months and 12 months, and the incidence of acute pancreatitis.At baseline, the median triglyceride level was 2044 mg per deciliter. At 10 months, the median change from baseline in the fasting triglyceride level (the primary end point) was -80% in the 25-mg plozasiran group, -78% in the 50-mg plozasiran group, and -17% in the placebo group (P<0.001). The key secondary end points showed better results in the plozasiran groups than in the placebo group, including the incidence of acute pancreatitis (odds ratio, 0.17; 95% confidence interval, 0.03 to 0.94; P = 0.03). The risk of adverse events was similar across groups; the most common adverse events were abdominal pain, nasopharyngitis, headache, and nausea. Severe and serious adverse events were less common with plozasiran than with placebo. Hyperglycemia with plozasiran occurred in some patients with prediabetes or diabetes at baseline.Patients with persistent chylomicronemia who received plozasiran had significantly lower triglyceride levels and a lower incidence of pancreatitis than those who received placebo. (Funded by Arrowhead Pharmaceuticals; PALISADE ClinicalTrials.gov number, NCT05089084.).

    View details for DOI 10.1056/NEJMoa2409368

    View details for PubMedID 39225259

  • Plozasiran, an RNA Interference Agent Targeting APOC3, for Mixed Hyperlipidemia. The New England journal of medicine Ballantyne, C. M., Vasas, S., Azizad, M., Clifton, P., Rosenson, R. S., Chang, T., Melquist, S., Zhou, R., Mushin, M., Leeper, N. J., Hellawell, J., Gaudet, D. 2024

    Abstract

    BACKGROUND: Persons with mixed hyperlipidemia are at risk for atherosclerotic cardiovascular disease due to an elevated non-high-density lipoprotein (HDL) cholesterol level, which is driven by remnant cholesterol in triglyceride-rich lipoproteins. The metabolism and clearance of triglyceride-rich lipoproteins are down-regulated through apolipoprotein C3 (APOC3)-mediated inhibition of lipoprotein lipase.METHODS: We carried out a 48-week, phase 2b, double-blind, randomized, placebo-controlled trial evaluating the safety and efficacy of plozasiran, a hepatocyte-targeted APOC3 small interfering RNA, in patients with mixed hyperlipidemia (i.e., a triglyceride level of 150 to 499 mg per deciliter and either a low-density lipoprotein [LDL] cholesterol level of ≥70 mg per deciliter or a non-HDL cholesterol level of ≥100 mg per deciliter). The participants were assigned in a 3:1 ratio to receive plozasiran or placebo within each of four cohorts. In the first three cohorts, the participants received a subcutaneous injection of plozasiran (10 mg, 25 mg, or 50 mg) or placebo on day 1 and at week 12 (quarterly doses). In the fourth cohort, participants received 50 mg of plozasiran or placebo on day 1 and at week 24 (half-yearly dose). The data from the participants who received placebo were pooled. The primary end point was the percent change in fasting triglyceride level at week 24.RESULTS: A total of 353 participants underwent randomization. At week 24, significant reductions in the fasting triglyceride level were observed with plozasiran, with differences, as compared with placebo, in the least-squares mean percent change from baseline of -49.8 percentage points (95% confidence interval [CI], -59.0 to -40.6) with the 10-mg-quarterly dose, -56.0 percentage points (95% CI, -65.1 to -46.8) with the 25-mg-quarterly dose, -62.4 percentage points (95% CI, -71.5 to -53.2) with the 50-mg-quarterly dose, and -44.2 percentage points (95% CI, -53.4 to -35.0) with the 50-mg-half-yearly dose (P<0.001 for all comparisons). Worsening glycemic control was observed in 10% of the participants receiving placebo, 12% of those receiving the 10-mg-quarterly dose, 7% of those receiving the 25-mg-quarterly dose, 20% of those receiving the 50-mg-quarterly dose, and 21% of those receiving the 50-mg-half-yearly dose.CONCLUSIONS: In this randomized, controlled trial involving participants with mixed hyperlipidemia, plozasiran, as compared with placebo, significantly reduced triglyceride levels at 24 weeks. A clinical outcomes trial is warranted. (Funded by Arrowhead Pharmaceuticals; MUIR ClinicalTrials.gov number NCT04998201.).

    View details for DOI 10.1056/NEJMoa2404143

    View details for PubMedID 38804517

  • Efferocytosis in atherosclerosis. Nature reviews. Cardiology Adkar, S. S., Leeper, N. J. 2024

    Abstract

    Cardiovascular disease is the leading cause of death worldwide, and it commonly results from atherosclerotic plaque progression. One of the increasingly recognized drivers of atherosclerosis is dysfunctional efferocytosis, a homeostatic mechanism responsible for the clearance of dead cells and the resolution of inflammation. In atherosclerosis, the capacity of phagocytes to participate in efferocytosis is hampered, leading to the accumulation of apoptotic and necrotic tissue within the plaque, which results in enlargement of the necrotic core, increased luminal stenosis and plaque inflammation, and predisposition to plaque rupture or erosion. In this Review, we describe the different forms of programmed cell death that can occur in the atherosclerotic plaque and highlight the efferocytic machinery that is normally implicated in cardiovascular physiology. We then discuss the mechanisms by which efferocytosis fails in atherosclerosis and other cardiovascular and cardiometabolic diseases, including myocardial infarction and diabetes mellitus, and discuss therapeutic approaches that might reverse this pathological process.

    View details for DOI 10.1038/s41569-024-01037-7

    View details for PubMedID 38750215

    View details for PubMedCentralID 295839

  • Risk of Cancer After Diagnosis of Cardiovascular Disease. JACC. CardioOncology Bell, C. F., Lei, X., Haas, A., Baylis, R. A., Gao, H., Luo, L., Giordano, S. H., Wehner, M. R., Nead, K. T., Leeper, N. J. 2023; 5 (4): 431-440

    Abstract

    Cardiovascular disease (CVD) and cancer share several risk factors. Although preclinical models show that various types of CVD can accelerate cancer progression, clinical studies have not determined the impact of atherosclerosis on cancer risk.The objective of this study was to determine whether CVD, especially atherosclerotic CVD, is independently associated with incident cancer.Using IBM MarketScan claims data from over 130 million individuals, 27 million cancer-free subjects with a minimum of 36 months of follow-up data were identified. Individuals were stratified by presence or absence of CVD, time-varying analysis with multivariable adjustment for cardiovascular risk factors was performed, and cumulative risk of cancer was calculated. Additional analyses were performed according to CVD type (atherosclerotic vs nonatherosclerotic) and cancer subtype.Among 27,195,088 individuals, those with CVD were 13% more likely to develop cancer than those without CVD (HR: 1.13; 95% CI: 1.12-1.13). Results were more pronounced for individuals with atherosclerotic CVD (aCVD), who had a higher risk of cancer than those without CVD (HR: 1.20; 95% CI: 1.19-1.21). aCVD also conferred a higher risk of cancer compared with those with nonatherosclerotic CVD (HR: 1.11; 95% CI: 1.11-1.12). Cancer subtype analyses showed specific associations of aCVD with several malignancies, including lung, bladder, liver, colon, and other hematologic cancers.Individuals with CVD have an increased risk of developing cancer compared with those without CVD. This association may be driven in part by the relationship of atherosclerosis with specific cancer subtypes, which persists after controlling for conventional risk factors.

    View details for DOI 10.1016/j.jaccao.2023.01.010

    View details for PubMedID 37614573

    View details for PubMedCentralID PMC10443115

  • An Alternate Explanation. The New England journal of medicine Alsaigh, T., Dhaliwal, G., Fukaya, E., Leeper, N. J., Sayed, N. 2023; 388 (14): 1318-1324

    View details for DOI 10.1056/NEJMcps2210419

    View details for PubMedID 37018496

  • Clustering cancers by shared transcriptional risk reveals novel targets for cancer therapy. Molecular cancer Gao, H., Baylis, R. A., Luo, L., Kojima, Y., Bell, C. F., Ross, E. G., Wang, F., Leeper, N. J. 2022; 21 (1): 116

    View details for DOI 10.1186/s12943-022-01592-y

    View details for PubMedID 35585548

  • The pleiotropic benefits of statins include the ability to reduce CD47 and amplify the effect of pro-efferocytic therapies in atherosclerosis. Nature cardiovascular research Jarr, K., Ye, J., Kojima, Y., Ye, Z., Gao, H., Schmid, S., Luo, L., Baylis, R. A., Lotfi, M., Lopez, N., Eberhard, A. V., Smith, B. R., Weissman, I. L., Maegdefessel, L., Leeper, N. J. 2022; 1 (3): 253-262

    Abstract

    The pleiotropic benefits of statins may result from their impact on vascular inflammation. The molecular process underlying this phenomenon is not fully elucidated. Here, RNA sequencing designed to investigate gene expression patterns following CD47-SIRPalpha inhibition identifies a link between statins, efferocytosis, and vascular inflammation. In vivo and in vitro studies provide evidence that statins augment programmed cell removal by inhibiting the nuclear translocation of NFkappaB1 p50 and suppressing the expression of the critical 'don't eat me' molecule, CD47. Statins amplify the phagocytic capacity of macrophages, and thus the anti-atherosclerotic effects of CD47-SIRPalpha blockade, in an additive manner. Analyses of clinical biobank specimens suggest a similar link between statins and CD47 expression in humans, highlighting the potential translational implications. Taken together, our findings identify efferocytosis and CD47 as pivotal mediators of statin pleiotropy. In turn, statins amplify the anti-atherosclerotic effects of pro-phagocytic therapies independently of any lipid-lowering effect.

    View details for DOI 10.1038/s44161-022-00023-x

    View details for PubMedID 35990913

  • Bench-to-Bedside in Vascular Medicine: Optimizing the Translational Pipeline for Patients With Peripheral Artery Disease. Circulation research Alsaigh, T., Di Bartolo, B. A., Mulangala, J., Figtree, G. A., Leeper, N. J. 2021; 128 (12): 1927-1943

    Abstract

    Peripheral arterial disease is a growing worldwide problem with a wide spectrum of clinical severity and is projected to consume >$21 billion per year in the United States alone. While vascular researchers have brought several therapies to the clinic in recent years, few of these approaches have leveraged advances in high-throughput discovery screens, novel translational models, or innovative trial designs. In the following review, we discuss recent advances in unbiased genomics and broader omics technology platforms, along with preclinical vascular models designed to enhance our understanding of disease pathobiology and prioritize targets for additional investigation. Furthermore, we summarize novel approaches to clinical studies in subjects with claudication and ischemic ulceration, with an emphasis on streamlining and accelerating bench-to-bedside translation. By providing a framework designed to enhance each aspect of future clinical development programs, we hope to enrich the pipeline of therapies that may prevent loss of life and limb for those with peripheral arterial disease.

    View details for DOI 10.1161/CIRCRESAHA.121.318265

    View details for PubMedID 34110900

  • Effect of CD47 Blockade on Vascular Inflammation. The New England journal of medicine Jarr, K. U., Nakamoto, R. n., Doan, B. H., Kojima, Y. n., Weissman, I. L., Advani, R. H., Iagaru, A. n., Leeper, N. J. 2021; 384 (4): 382–83

    View details for DOI 10.1056/NEJMc2029834

    View details for PubMedID 33503349

  • Knockout of the Murine Ortholog to the Human 9p21 Coronary Artery Disease Locus Leads to Smooth Muscle Cell Proliferation, Vascular Calcification, and Advanced Atherosclerosis. Circulation Kojima, Y., Ye, J., Nanda, V., Wang, Y., Flores, A. M., Jarr, K., Tsantilas, P., Guo, L., Finn, A. V., Virmani, R., Leeper, N. J. 2020; 141 (15): 1274–76

    View details for DOI 10.1161/CIRCULATIONAHA.119.043413

    View details for PubMedID 32282248

  • Pro-efferocytic nanoparticles are specifically taken up by lesional macrophages and prevent atherosclerosis. Nature nanotechnology Flores, A. M., Hosseini-Nassab, N. n., Jarr, K. U., Ye, J. n., Zhu, X. n., Wirka, R. n., Koh, A. L., Tsantilas, P. n., Wang, Y. n., Nanda, V. n., Kojima, Y. n., Zeng, Y. n., Lotfi, M. n., Sinclair, R. n., Weissman, I. L., Ingelsson, E. n., Smith, B. R., Leeper, N. J. 2020

    Abstract

    Atherosclerosis is the process that underlies heart attack and stroke. A characteristic feature of the atherosclerotic plaque is the accumulation of apoptotic cells in the necrotic core. Prophagocytic antibody-based therapies are currently being explored to stimulate the phagocytic clearance of apoptotic cells; however, these therapies can cause off-target clearance of healthy tissues, which leads to toxicities such as anaemia. Here we developed a macrophage-specific nanotherapy based on single-walled carbon nanotubes loaded with a chemical inhibitor of the antiphagocytic CD47-SIRPα signalling axis. We demonstrate that these single-walled carbon nanotubes accumulate within the atherosclerotic plaque, reactivate lesional phagocytosis and reduce the plaque burden in atheroprone apolipoprotein-E-deficient mice without compromising safety, and thereby overcome a key translational barrier for this class of drugs. Single-cell RNA sequencing analysis reveals that prophagocytic single-walled carbon nanotubes decrease the expression of inflammatory genes linked to cytokine and chemokine pathways in lesional macrophages, which demonstrates the potential of 'Trojan horse' nanoparticles to prevent atherosclerotic cardiovascular disease.

    View details for DOI 10.1038/s41565-019-0619-3

    View details for PubMedID 31988506

  • Clonally expanding smooth muscle cells promote atherosclerosis by escaping efferocytosis and activating the complement cascade. Proceedings of the National Academy of Sciences of the United States of America Wang, Y. n., Nanda, V. n., Direnzo, D. n., Ye, J. n., Xiao, S. n., Kojima, Y. n., Howe, K. L., Jarr, K. U., Flores, A. M., Tsantilas, P. n., Tsao, N. n., Rao, A. n., Newman, A. A., Eberhard, A. V., Priest, J. R., Ruusalepp, A. n., Pasterkamp, G. n., Maegdefessel, L. n., Miller, C. L., Lind, L. n., Koplev, S. n., Björkegren, J. L., Owens, G. K., Ingelsson, E. n., Weissman, I. L., Leeper, N. J. 2020

    Abstract

    Atherosclerosis is the process underlying heart attack and stroke. Despite decades of research, its pathogenesis remains unclear. Dogma suggests that atherosclerotic plaques expand primarily via the accumulation of cholesterol and inflammatory cells. However, recent evidence suggests that a substantial portion of the plaque may arise from a subset of "dedifferentiated" vascular smooth muscle cells (SMCs) which proliferate in a clonal fashion. Herein we use multicolor lineage-tracing models to confirm that the mature SMC can give rise to a hyperproliferative cell which appears to promote inflammation via elaboration of complement-dependent anaphylatoxins. Despite being extensively opsonized with prophagocytic complement fragments, we find that this cell also escapes immune surveillance by neighboring macrophages, thereby exacerbating its relative survival advantage. Mechanistic studies indicate this phenomenon results from a generalized opsonin-sensing defect acquired by macrophages during polarization. This defect coincides with the noncanonical up-regulation of so-called don't eat me molecules on inflamed phagocytes, which reduces their capacity for programmed cell removal (PrCR). Knockdown or knockout of the key antiphagocytic molecule CD47 restores the ability of macrophages to sense and clear opsonized targets in vitro, allowing for potent and targeted suppression of clonal SMC expansion in the plaque in vivo. Because integrated clinical and genomic analyses indicate that similar pathways are active in humans with cardiovascular disease, these studies suggest that the clonally expanding SMC may represent a translational target for treating atherosclerosis.

    View details for DOI 10.1073/pnas.2006348117

    View details for PubMedID 32541024

  • Clinical and Genetic Determinants of Varicose Veins Prospective, Community-Based Study of approximate to 500 000 Individuals CIRCULATION Fukaya, E., Flores, A. M., Lindholm, D., Gustafsson, S., Zanetti, D., Ingelsson, E., Leeper, N. J. 2018; 138 (25): 2869–80
  • Proefferocytic Therapy Promotes Transforming Growth Factor-beta Signaling and Prevents Aneurysm Formation CIRCULATION Kojima, Y., Werner, N., Ye, J., Nanda, V., Tsao, N., Wang, Y., Flores, A. M., Miller, C. L., Weissman, I., Deng, H., Xu, B., Dalman, R. L., Eken, S. M., Pelisek, J., Li, Y., Maegdefessel, L., Leeper, N. J. 2018; 137 (7): 750–53

    View details for PubMedID 29440201

    View details for PubMedCentralID PMC5819616

  • The Role of Efferocytosis in Atherosclerosis CIRCULATION Kojima, Y., Weissman, I. L., Leeper, N. J. 2017; 135 (5): 476-489

    Abstract

    The necrotic core has long been a hallmark of the vulnerable atherosclerotic plaque. Although apoptotic cells are cleared quickly in almost all other tissue beds, their removal appears to be significantly impaired in the diseased blood vessel. Emerging evidence indicates that this phenomenon is caused by a defect in efferocytosis, the process by which apoptotic tissue is recognized for engulfment by phagocytic cells such as macrophages. Genetic and experimental data suggest that efferocytosis is impaired during atherogenesis caused by dysregulation of so-called eat me ligands, which govern the edibility of cells undergoing programmed cell death. The following is a summary of recent data indicating that efferocytosis is a major unappreciated driver of lesion expansion but also a reversible defect that can potentially be targeted as a means to prevent plaque progression.

    View details for DOI 10.1161/CIRCULATIONAHA.116.025684

    View details for Web of Science ID 000393716200009

    View details for PubMedID 28137963

    View details for PubMedCentralID PMC5302553

  • Canagliflozin and Cardiovascular and Renal Events in Type 2 Diabetes. The New England journal of medicine Neal, B. n., Perkovic, V. n., Mahaffey, K. W., de Zeeuw, D. n., Fulcher, G. n., Erondu, N. n., Shaw, W. n., Law, G. n., Desai, M. n., Matthews, D. R. 2017; 377 (7): 644–57

    Abstract

    Background Canagliflozin is a sodium-glucose cotransporter 2 inhibitor that reduces glycemia as well as blood pressure, body weight, and albuminuria in people with diabetes. We report the effects of treatment with canagliflozin on cardiovascular, renal, and safety outcomes. Methods The CANVAS Program integrated data from two trials involving a total of 10,142 participants with type 2 diabetes and high cardiovascular risk. Participants in each trial were randomly assigned to receive canagliflozin or placebo and were followed for a mean of 188.2 weeks. The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. Results The mean age of the participants was 63.3 years, 35.8% were women, the mean duration of diabetes was 13.5 years, and 65.6% had a history of cardiovascular disease. The rate of the primary outcome was lower with canagliflozin than with placebo (occurring in 26.9 vs. 31.5 participants per 1000 patient-years; hazard ratio, 0.86; 95% confidence interval [CI], 0.75 to 0.97; P<0.001 for noninferiority; P=0.02 for superiority). Although on the basis of the prespecified hypothesis testing sequence the renal outcomes are not viewed as statistically significant, the results showed a possible benefit of canagliflozin with respect to the progression of albuminuria (hazard ratio, 0.73; 95% CI, 0.67 to 0.79) and the composite outcome of a sustained 40% reduction in the estimated glomerular filtration rate, the need for renal-replacement therapy, or death from renal causes (hazard ratio, 0.60; 95% CI, 0.47 to 0.77). Adverse reactions were consistent with the previously reported risks associated with canagliflozin except for an increased risk of amputation (6.3 vs. 3.4 participants per 1000 patient-years; hazard ratio, 1.97; 95% CI, 1.41 to 2.75); amputations were primarily at the level of the toe or metatarsal. Conclusions In two trials involving patients with type 2 diabetes and an elevated risk of cardiovascular disease, patients treated with canagliflozin had a lower risk of cardiovascular events than those who received placebo but a greater risk of amputation, primarily at the level of the toe or metatarsal. (Funded by Janssen Research and Development; CANVAS and CANVAS-R ClinicalTrials.gov numbers, NCT01032629 and NCT01989754 , respectively.).

    View details for PubMedID 28605608

  • CD47-blocking antibodies restore phagocytosis and prevent atherosclerosis. Nature Kojima, Y., Volkmer, J., McKenna, K., Civelek, M., Lusis, A. J., Miller, C. L., DiRenzo, D., Nanda, V., Ye, J., Connolly, A. J., Schadt, E. E., Quertermous, T., Betancur, P., Maegdefessel, L., Matic, L. P., Hedin, U., Weissman, I. L., Leeper, N. J. 2016; 536 (7614): 86-90

    Abstract

    Atherosclerosis is the disease process that underlies heart attack and stroke. Advanced lesions at risk of rupture are characterized by the pathological accumulation of diseased vascular cells and apoptotic cellular debris. Why these cells are not cleared remains unknown. Here we show that atherogenesis is associated with upregulation of CD47, a key anti-phagocytic molecule that is known to render malignant cells resistant to programmed cell removal, or 'efferocytosis'. We find that administration of CD47-blocking antibodies reverses this defect in efferocytosis, normalizes the clearance of diseased vascular tissue, and ameliorates atherosclerosis in multiple mouse models. Mechanistic studies implicate the pro-atherosclerotic factor TNF-α as a fundamental driver of impaired programmed cell removal, explaining why this process is compromised in vascular disease. Similar to recent observations in cancer, impaired efferocytosis appears to play a pathogenic role in cardiovascular disease, but is not a fixed defect and may represent a novel therapeutic target.

    View details for PubMedID 27437576

  • CDKN2B Regulates TGFß Signaling and Smooth Muscle Cell Investment of Hypoxic Neovessels. Circulation research Nanda, V., Downing, K. P., Ye, J., Xiao, S., Kojima, Y., Spin, J. M., DiRenzo, D., Nead, K. T., Connolly, A. J., Dandona, S., Perisic, L., Hedin, U., Maegdefessel, L., Dalman, J., Guo, L., Zhao, X., Kolodgie, F. D., Virmani, R., Davis, H. R., Leeper, N. J. 2016; 118 (2): 230-240

    Abstract

    Genetic variation at the chromosome 9p21 cardiovascular risk locus has been associated with peripheral artery disease, but its mechanism remains unknown.To determine whether this association is secondary to an increase in atherosclerosis, or it is the result of a separate angiogenesis-related mechanism.Quantitative evaluation of human vascular samples revealed that carriers of the 9p21 risk allele possess a significantly higher burden of immature intraplaque microvessels than carriers of the ancestral allele, irrespective of lesion size or patient comorbidity. To determine whether aberrant angiogenesis also occurs under nonatherosclerotic conditions, we performed femoral artery ligation surgery in mice lacking the 9p21 candidate gene, Cdkn2b. These animals developed advanced hindlimb ischemia and digital autoamputation, secondary to a defect in the capacity of the Cdkn2b-deficient smooth muscle cell to support the developing neovessel. Microarray studies identified impaired transforming growth factor β (TGFβ) signaling in cultured cyclin-dependent kinase inhibitor 2B (CDKN2B)-deficient cells, as well as TGFβ1 upregulation in the vasculature of 9p21 risk allele carriers. Molecular signaling studies indicated that loss of CDKN2B impairs the expression of the inhibitory factor, SMAD-7, which promotes downstream TGFβ activation. Ultimately, this manifests in the upregulation of a poorly studied effector molecule, TGFβ1-induced-1, which is a TGFβ-rheostat known to have antagonistic effects on the endothelial cell and smooth muscle cell. Dual knockdown studies confirmed the reversibility of the proposed mechanism, in vitro.These results suggest that loss of CDKN2B may not only promote cardiovascular disease through the development of atherosclerosis but may also impair TGFβ signaling and hypoxic neovessel maturation.

    View details for DOI 10.1161/CIRCRESAHA.115.307906

    View details for PubMedID 26596284

    View details for PubMedCentralID PMC4740238

  • The Genetic Basis of Peripheral Arterial Disease Current Knowledge, Challenges, and Future Directions CIRCULATION RESEARCH Kullo, I. J., Leeper, N. J. 2015; 116 (9): 1551-1560

    Abstract

    Several risk factors for atherosclerotic peripheral arterial disease (PAD), such as dyslipidemia, diabetes mellitus, and hypertension, are heritable. However, predisposition to PAD may be influenced by genetic variants acting independently of these risk factors. Identification of such genetic variants will provide insights into underlying pathophysiologic mechanisms and facilitate the development of novel diagnostic and therapeutic approaches. In contrast to coronary heart disease, relatively few genetic variants that influence susceptibility to PAD have been discovered. This may be, in part, because of greater clinical and genetic heterogeneity in PAD. In this review, we (1) provide an update on the current state of knowledge about the genetic basis of PAD, including results of family studies and candidate gene, linkage as well as genome-wide association studies; (2) highlight the challenges in investigating the genetic basis of PAD and possible strategies to overcome these challenges; and (3) discuss the potential of genome sequencing, RNA sequencing, differential gene expression, epigenetic profiling, and systems biology in increasing our understanding of the molecular genetics of PAD.

    View details for DOI 10.1161/CIRCRESAHA.116.303518

    View details for Web of Science ID 000353383600005

    View details for PubMedID 25908728

    View details for PubMedCentralID PMC4410432

  • Cyclin-dependent kinase inhibitor 2B regulates efferocytosis and atherosclerosis JOURNAL OF CLINICAL INVESTIGATION Kojima, Y., Downing, K., Kundu, R., Miller, C., Dewey, F., Lancero, H., Raaz, U., Perisic, L., Hedin, U., Schadt, E., Maegdefessel, L., Quertermous, T., Leeper, N. J. 2014; 124 (3): 1083-1097

    Abstract

    Genetic variation at the chromosome 9p21 risk locus promotes cardiovascular disease; however, it is unclear how or which proteins encoded at this locus contribute to disease. We have previously demonstrated that loss of one candidate gene at this locus, cyclin-dependent kinase inhibitor 2B (Cdkn2b), in mice promotes vascular SMC apoptosis and aneurysm progression. Here, we investigated the role of Cdnk2b in atherogenesis and found that in a mouse model of atherosclerosis, deletion of Cdnk2b promoted advanced development of atherosclerotic plaques composed of large necrotic cores. Furthermore, human carriers of the 9p21 risk allele had reduced expression of CDKN2B in atherosclerotic plaques, which was associated with impaired expression of calreticulin, a ligand required for activation of engulfment receptors on phagocytic cells. As a result of decreased calreticulin, CDKN2B-deficient apoptotic bodies were resistant to efferocytosis and not efficiently cleared by neighboring macrophages. These uncleared SMCs elicited a series of proatherogenic juxtacrine responses associated with increased foam cell formation and inflammatory cytokine elaboration. The addition of exogenous calreticulin reversed defects associated with loss of Cdkn2b and normalized engulfment of Cdkn2b-deficient cells. Together, these data suggest that loss of CDKN2B promotes atherosclerosis by increasing the size and complexity of the lipid-laden necrotic core through impaired efferocytosis.

    View details for DOI 10.1172/JCI70391

    View details for Web of Science ID 000332347700028

    View details for PubMedID 24531546

  • Alternative Ankle-Brachial Index Method Identifies Additional At-Risk Individuals JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Nead, K. T., Cooke, J. P., Olin, J. W., Leeper, N. J. 2013; 62 (6): 553-559

    Abstract

    OBJECTIVES: To determine whether utilization of an alternative ankle-brachial index (ABI) calculation method improves mortality risk prediction compared to traditional methods. BACKGROUND: The ABI is used to diagnose peripheral arterial disease (PAD), and to identify those at risk for cardiovascular events. Traditionally, the ABI is calculated using the higher of the dorsalis pedis and posterior tibial ankle arteries. Studies directly comparing calculation methods are limited. METHODS: The ABI was calculated at baseline in 1,413 study participants undergoing non-emergent coronary angiography subsequently followed for all-cause and cardiovascular mortality. There were 224 individuals assigned to the traditional-PAD group (ABI < 0.90) using the traditional ABI method. Of those remaining, an alternative ABI method utilizing the lower of the two ankle pressures assigned 282 patients to the alternative-PAD group. The 862 individuals not assigned to PAD by either method were the no-PAD group. RESULTS: There were 163 mortalities during a median follow-up of 5.0 years. Adjusted Cox regression models showed that the alternative-PAD group had an increased risk for all-cause (HR=1.49; 95% CI, 1.01-2.19) and cardiovascular mortality (HR=3.21; 95% CI, 1.53-6.37) versus the no-PAD group. Additionally, in the no-PAD group, there was an 11% (HR=1.11; 95% CI, 1.05-1.17) increased risk of all-cause mortality per 1mm Hg increased difference between the left and right brachial systolic pressures. CONCLUSION: The implementation of an alternative ABI method and use of the brachial difference identifies individuals at an increased risk for mortality who are currently missed using traditional ABI methods. Current ABI protocols may need to be evaluated.

    View details for DOI 10.1016/j.jacc.2013.04.061

    View details for Web of Science ID 000322524300011

    View details for PubMedID 23707317

  • Loss of CDKN2B promotes p53-dependent smooth muscle cell apoptosis and aneurysm formation. Arteriosclerosis, thrombosis, and vascular biology Leeper, N. J., Raiesdana, A., Kojima, Y., Kundu, R. K., Cheng, H., Maegdefessel, L., Toh, R., Ahn, G., Ali, Z. A., Anderson, D. R., Miller, C. L., Roberts, S. C., Spin, J. M., de Almeida, P. E., Wu, J. C., Xu, B., Cheng, K., Quertermous, M., Kundu, S., Kortekaas, K. E., Berzin, E., Downing, K. P., Dalman, R. L., Tsao, P. S., Schadt, E. E., Owens, G. K., Quertermous, T. 2013; 33 (1): e1-e10

    Abstract

    Genomewide association studies have implicated allelic variation at 9p21.3 in multiple forms of vascular disease, including atherosclerotic coronary heart disease and abdominal aortic aneurysm. As for other genes at 9p21.3, human expression quantitative trait locus studies have associated expression of the tumor suppressor gene CDKN2B with the risk haplotype, but its potential role in vascular pathobiology remains unclear.Here we used vascular injury models and found that Cdkn2b knockout mice displayed the expected increase in proliferation after injury, but developed reduced neointimal lesions and larger aortic aneurysms. In situ and in vitro studies suggested that these effects were attributable to increased smooth muscle cell apoptosis. Adoptive bone marrow transplant studies confirmed that the observed effects of Cdkn2b were mediated through intrinsic vascular cells and were not dependent on bone marrow-derived inflammatory cells. Mechanistic studies suggested that the observed increase in apoptosis was attributable to a reduction in MDM2 and an increase in p53 signaling, possibly due in part to compensation by other genes at the 9p21.3 locus. Dual inhibition of both Cdkn2b and p53 led to a reversal of the vascular phenotype in each model.These results suggest that reduced CDKN2B expression and increased smooth muscle cell apoptosis may be one mechanism underlying the 9p21.3 association with aneurysmal disease.

    View details for DOI 10.1161/ATVBAHA.112.300399

    View details for PubMedID 23162013

  • MicroRNA-21 Blocks Abdominal Aortic Aneurysm Development and Nicotine-Augmented Expansion SCIENCE TRANSLATIONAL MEDICINE Maegdefessel, L., Azuma, J., Toh, R., Deng, A., Merk, D. R., Raiesdana, A., Leeper, N. J., Raaz, U., Schoelmerich, A. M., McConnell, M. V., Dalman, R. L., Spin, J. M., Tsao, P. S. 2012; 4 (122)

    Abstract

    Identification and treatment of abdominal aortic aneurysm (AAA) remains among the most prominent challenges in vascular medicine. MicroRNAs are crucial regulators of cardiovascular pathology and represent possible targets for the inhibition of AAA expansion. We identified microRNA-21 (miR-21) as a key modulator of proliferation and apoptosis of vascular wall smooth muscle cells during development of AAA in two established murine models. In both models (AAA induced by porcine pancreatic elastase or infusion of angiotensin II), miR-21 expression increased as AAA developed. Lentiviral overexpression of miR-21 induced cell proliferation and decreased apoptosis in the aortic wall, with protective effects on aneurysm expansion. miR-21 overexpression substantially decreased expression of the phosphatase and tensin homolog (PTEN) protein, leading to increased phosphorylation and activation of AKT, a component of a pro-proliferative and antiapoptotic pathway. Systemic injection of a locked nucleic acid-modified antagomir targeting miR-21 diminished the pro-proliferative impact of down-regulated PTEN, leading to a marked increase in the size of AAA. Similar results were seen in mice with AAA augmented by nicotine and in human aortic tissue samples from patients undergoing surgical repair of AAA (with more pronounced effects observed in smokers). Modulation of miR-21 expression shows potential as a new therapeutic option to limit AAA expansion and vascular disease progression.

    View details for DOI 10.1126/scitranslmed.3003441

    View details for PubMedID 22357537

  • MicroRNA-26a Is a Novel Regulator of Vascular Smooth Muscle Cell Function JOURNAL OF CELLULAR PHYSIOLOGY Leeper, N. J., Raiesdana, A., Kojima, Y., Chun, H. J., Azuma, J., Maegdefessel, L., Kundu, R. K., Quertermous, T., Tsao, P. S., Spin, J. M. 2011; 226 (4): 1035-1043

    Abstract

    Aberrant smooth muscle cell (SMC) plasticity has been implicated in a variety of vascular disorders including atherosclerosis, restenosis, and abdominal aortic aneurysm (AAA) formation. While the pathways governing this process remain unclear, epigenetic regulation by specific microRNAs (miRNAs) has been demonstrated in SMCs. We hypothesized that additional miRNAs might play an important role in determining vascular SMC phenotype. Microarray analysis of miRNAs was performed on human aortic SMCs undergoing phenotypic switching in response to serum withdrawal, and identified 31 significantly regulated entities. We chose the highly conserved candidate miRNA-26a for additional studies. Inhibition of miRNA-26a accelerated SMC differentiation, and also promoted apoptosis, while inhibiting proliferation and migration. Overexpression of miRNA-26a blunted differentiation. As a potential mechanism, we investigated whether miRNA-26a influences TGF-β-pathway signaling. Dual-luciferase reporter assays demonstrated enhanced SMAD signaling with miRNA-26a inhibition, and the opposite effect with miRNA-26a overexpression in transfected human cells. Furthermore, inhibition of miRNA-26a increased gene expression of SMAD-1 and SMAD-4, while overexpression inhibited SMAD-1. MicroRNA-26a was also found to be downregulated in two mouse models of AAA formation (2.5- to 3.8-fold decrease, P < 0.02) in which enhanced switching from contractile to synthetic phenotype occurs. In summary, miRNA-26a promotes vascular SMC proliferation while inhibiting cellular differentiation and apoptosis, and alters TGF-β pathway signaling. MicroRNA-26a represents an important new regulator of SMC biology and a potential therapeutic target in AAA disease.

    View details for DOI 10.1002/jcp.22422

    View details for Web of Science ID 000287258800019

    View details for PubMedID 20857419

    View details for PubMedCentralID PMC3108574

  • Stem Cell Therapy for Vascular Regeneration Adult, Embryonic, and Induced Pluripotent Stem Cells CIRCULATION Leeper, N. J., Hunter, A. L., Cooke, J. P. 2010; 122 (5): 517-526
  • Apelin prevents aortic aneurysm formation by inhibiting macrophage inflammation AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Leeper, N. J., Tedesco, M. M., Kojima, Y., Schultz, G. M., Kundu, R. K., Ashley, E. A., Tsao, P. S., Dalman, R. L., Quertermous, T. 2009; 296 (5): H1329-H1335

    Abstract

    Apelin is a potent inodilator with recently described antiatherogenic properties. We hypothesized that apelin might also attenuate abdominal aortic aneurysm (AAA) formation by limiting disease-related vascular wall inflammation. C57BL/6 mice implanted with osmotic pumps filled with apelin or saline were treated with pancreatic elastase to create infrarenal AAAs. Mice were euthanized for aortic PCR analysis or followed ultrasonographically and then euthanized for histological analysis. The cellular expression of inflammatory cytokines and chemokines in response to apelin was also assessed in cultured macrophages, smooth muscle cells, and fibroblasts. Apelin treatment resulted in diminished AAA formation, with a 47% reduction in maximal cross-sectional area (0.74 vs. 1.39 mm(2), P < 0.03) and a 57% reduction in macrophage infiltrate (113 vs. 261.3 cells/high-power field, P < 0.0001) relative to the saline-treated group. Apelin infusion was also associated with significantly reduced aortic macrophage colony-stimulating factor expression and decreased monocyte chemattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha mean mRNA levels. Apelin stimulation of cultured macrophages significantly reduced MCP-1 and TNF-alpha mRNA levels relative to baseline (2.03- and 1.89-fold reduction, P < 0.03, respectively) but did not affect intimal adhesion molecule expression or medial or adventitial cell cytokine production. Apelin significantly reduces aneurysm formation in the elastase model of human AAA disease. The mechanism appears to be decreased macrophage burden, perhaps related to an apelin-mediated decrease in proinflammatory cytokine and chemokine activation.

    View details for DOI 10.1152/ajpheart.01341.2008

    View details for Web of Science ID 000265659100020

    View details for PubMedID 19304942

    View details for PubMedCentralID PMC2685356

  • Clinical problem-solving. Fool's Gold. New England journal of medicine Leeper, N. J., Dhaliwal, G., Saint, S., Witteles, R. M. 2008; 359 (19): 2035-2041

    View details for DOI 10.1056/NEJMcps0802668

    View details for PubMedID 18987372

  • Statin use in patients with extremely low low-density lipoprotein levels is associated with improved survival CIRCULATION Leeper, N. J., Ardehali, R., DeGoma, E. M., Heidenreich, P. A. 2007; 116 (6): 613-618

    Abstract

    Aggressive lipid management has recently become the standard of care for patients with coronary heart disease. The safety and effectiveness of statin usage for patients with extremely low low-density lipoprotein (LDL) levels are less clear, however. The aim of this study was to investigate the safety and clinical outcomes of statin treatment in patients with LDL cholesterol levels below 60 mg/dL.A total of 6107 consecutive patients with LDL levels less than 60 mg/dL were identified from a tertiary care medical center or affiliated community clinic. Statin therapy was defined as a prescription during the 150 days after the low LDL value was obtained. The propensity to be treated with a statin was used to adjust the association of statin therapy and survival. A total of 4295 patients (70%) had at least 1 prescription for any medication during the 150-day observation period after the low LDL value. Their mean age was 65 years, 43% had prior ischemic heart disease, and 47% had diabetes mellitus. Statins were prescribed in 2564 patients (60%) after the low LDL value was observed. During a mean follow-up of 2.0+/-1.4 years after the observation period, there were 510 deaths. After controlling for the propensity to receive a statin, statin therapy was associated with improved survival (hazard ratio [HR], 0.65; 95% CI, 0.53 to 0.80). This lower mortality was also observed for subgroups of patients already taking statins at baseline (HR, 0.58; 95% CI, 0.38 to 0.88), those with extremely low LDL levels (<40 mg/dL, n=623; HR, 0.51; 95% CI, 0.33 to 0.79), and those without a history of ischemic heart disease (n=2438; HR, 0.58; 95% CI, 0.42 to 0.80). Statin use was not associated with an increase in malignancy, transaminase elevation, or rhabdomyolysis.Statin therapy in the setting of a very low LDL level appears to be safe and is associated with improved survival.

    View details for DOI 10.1161/CIRCULATIONAHA.107.694117

    View details for Web of Science ID 000248572300010

    View details for PubMedID 17664373

  • Clinical problem-solving. One surprise after another. New England journal of medicine Leeper, N. J., Wener, L. S., Dhaliwal, G., Saint, S., Wachter, R. M. 2005; 352 (14): 1474-1479

    View details for PubMedID 15814884

  • Cloning of a unique lipase from endothelial cells extends the lipase gene family JOURNAL OF BIOLOGICAL CHEMISTRY Hirata, K., Dichek, H. L., Cioffi, J. A., Choi, S. Y., Leeper, N. J., Quintana, L., Kronmal, G. S., Cooper, A. D., Quertermous, T. 1999; 274 (20): 14170-14175

    Abstract

    A new lipoprotein lipase-like gene has been cloned from endothelial cells through a subtraction methodology aimed at characterizing genes that are expressed with in vitro differentiation of this cell type. The conceptual endothelial cell-derived lipase protein contains 500 amino acids, including an 18-amino acid hydrophobic signal sequence, and is 44% identical to lipoprotein lipase and 41% identical to hepatic lipase. Comparison of primary sequence to that of lipoprotein and hepatic lipase reveals conservation of the serine, aspartic acid, and histidine catalytic residues as well as the 10 cysteine residues involved in disulfide bond formation. Expression was identified in cultured human umbilical vein endothelial cells, human coronary artery endothelial cells, and murine endothelial-like yolk sac cells by Northern blot. In addition, Northern blot and in situ hybridization analysis revealed expression of the endothelial-derived lipase in placenta, liver, lung, ovary, thyroid gland, and testis. A c-Myc-tagged protein secreted from transfected COS7 cells had phospholipase A1 activity but no triglyceride lipase activity. Its tissue-restricted pattern of expression and its ability to be expressed by endothelial cells, suggests that endothelial cell-derived lipase may have unique functions in lipoprotein metabolism and in vascular disease.

    View details for Web of Science ID 000080322200064

    View details for PubMedID 10318835

  • ZODASIRAN SILENCES HEPATIC ANGPTL3 LEADING TO DEEP AND DURABLE REDUCTIONS IN ATHEROGENIC LIPIDS AND LIPOPROTEINS IN MIXED DYSLIPIDEMIA PATIENTS: FINAL RESULTS FROM ARCHES-2, DOUBLE-BLIND PERIOD Rosenson, R., Gaudet, D., Hegele, R., Ballantyne, C., Nicholls, S., Lucas, K., Hellawell, J., Chang, T., Fu, R., Muhsin, M., Leeper, N., Watts, G. ELSEVIER IRELAND LTD. 2024
  • Characterization of Peripheral Artery Disease and Associations with Traditional Risk Factors, Mobility, and Biomarkers in the Project Baseline Health Study. American heart journal Kercheval, J. B., Narcisse, D. I., Nguyen, M., Rao, S. V., Gutierrez, J. A., Leeper, N. J., Maron, D. J., Rodriguez, F., Hernandez, A. F., Mahaffey, K. W., Shah, S. H., Swaminathan, R. V. 2024

    Abstract

    There is a dearth of research on immunophenotyping in peripheral artery disease (PAD). This study aimed to describe the baseline characteristics, immunophenotypic profile, and quality of life (QoL) of participants with PAD in the Project Baseline Health Study (PBHS).The PBHS study is a prospective, multi-center, longitudinal cohort study that collected clinical, molecular, and biometric data from participants recruited between 2017 and 2018. In this analysis, baseline demographic, clinical, mobility, QoL, and flow cytometry data were stratified by the presence of PAD (ankle brachial index [ABI] ≤0.90).Of 2,209 participants, 58 (2.6%) had lower-extremity PAD, and only 2 (3.4%) had pre-existing PAD diagnosed prior to enrollment. Comorbid smoking (29.3% vs. 14%, p<0.001), hypertension (54% vs. 30%, p<0.001), diabetes (25% vs. 14%, p=0.031), and at least moderate coronary calcifications (Agatston score >100: 32% vs. 17%, p=0.01) were significantly higher in participants with PAD than in those with normal ABIs, as were high-sensitivity C-reactive protein levels (5.86 vs. 2.83, p<0.001). After adjusting for demographic and risk factors, participants with PAD had significantly fewer circulating CD56-high natural killer cells, IgM+ memory B cells, and CD10/CD27 double-positive B cells (p<0.05 for all).This study reinforces existing evidence that a large proportion of PAD without claudication may be underdiagnosed, particularly in female and Black or African American participants. We describe a novel immunophenotypic profile of participants with PAD that could represent a potential future screening or diagnostic tool to facilitate earlier diagnosis of PAD.NCT03154346, https://clinicaltrials.gov/ct2/show/NCT03154346.

    View details for DOI 10.1016/j.ahj.2024.06.010

    View details for PubMedID 38969081

  • Postdoctoral T32 training is correlated with obtaining an academic primarily research faculty position. PloS one Mueller, A. L., Schnirel, A., Kleppner, S., Tsao, P., Leeper, N. J. 2024; 19 (6): e0303792

    Abstract

    The mission of NIH-sponsored institutional training programs such as the T32 is to provide strong research and career training for early career scientists. One of the main avenues to pursuing health-related research is becoming research faculty at an academic institution. It is therefore important to know whether these programs are succeeding in this mission, or, if barriers exist that prevent trainees from pursuing these careers. Our institution currently trains ~ 2400 post-doctoral scholars per year, approximately 5% of whom are enrolled in one of our 33 T32 programs. In this study, we 1) compare the proximal professional career trajectories of T32 trainees with non-T32 trainees at our institution, 2) compare proximal career trajectories of trainees in a subset of cardiovascular T32 programs based on their previous training backgrounds, and 3) survey past and current T32 trainees in a subset of cardiovascular T32 programs about the barriers and enablers they experienced to pursuing research-oriented careers. We find that former T32 trainees are significantly more likely to attain appointments as primarily research faculty members, compared to other trainees. Trainees report a perceived lack of stability, the paucity of open positions, and the 'publish or perish' mentality of academia as the top barriers to pursuing careers in academia. However, they were still more likely to choose research over clinical careers after participating in a dedicated T32 program. Our results support the conclusion that structured training programs strengthen the pipeline of young scientists pursuing careers in academic research, including those from underrepresented backgrounds. However, T32 postdoctoral researchers are held back from pursuing academic careers by a perceived lack of stability and high competition for faculty positions.

    View details for DOI 10.1371/journal.pone.0303792

    View details for PubMedID 38848385

    View details for PubMedCentralID PMC11161096

  • Multiplex Imaging for Cell Phenotyping of Early Human Atherosclerosis. Journal of the American Heart Association Elishaev, M., Li, B., Zhou, A., Salim, K., Leeper, N. J., Francis, G. A., Lai, C., Wang, Y. 2024: e034990

    Abstract

    BACKGROUND: Previous studies using animal models and cultured cells suggest that vascular smooth muscle cells (SMCs) and inflammatory cytokines are important players in atherogenesis. Validating these findings in human disease is critical to designing therapeutics that target these components. Multiplex imaging is a powerful tool for characterizing cell phenotypes and microenvironments using biobanked human tissue sections. However, this technology has not been applied to human atherosclerotic lesions and needs to first be customized and validated.METHODS AND RESULTS: For validation, we created an 8-plex imaging panel to distinguish foam cells from SMC and leukocyte origins on tissue sections of early human atherosclerotic lesions (n=9). The spatial distribution and characteristics of these foam cells were further analyzed to test the association between SMC phenotypes and inflammation. Consistent with previous reports using human lesions, multiplex imaging showed that foam cells of SMC origin outnumbered those of leukocyte origin and were enriched in the deep intima, where the lipids accumulate in early atherogenesis. This new technology also found that apoptosis or the expression of pro-inflammatory cytokines were not more associated with foam cells than with nonfoam cells in early human lesions. More CD68+ SMCs were present among SMCs that highly expressed interleukin-1beta. Highly inflamed SMCs showed a trend of increased apoptosis, whereas leukocytes expressing similar levels of cytokines were enriched in regions of extracellular matrix remodeling.CONCLUSIONS: The multiplex imaging method can be applied to biobanked human tissue sections to enable proof-of-concept studies and validate theories based on animal models and cultured cells.

    View details for DOI 10.1161/JAHA.123.034990

    View details for PubMedID 38842292

  • Peripheral Artery Disease: Molecular Mechanisms and Novel Therapies. Arteriosclerosis, thrombosis, and vascular biology Athavale, A., Fukaya, E., Leeper, N. J. 2024; 44 (6): 1165-1170

    View details for DOI 10.1161/ATVBAHA.124.320195

    View details for PubMedID 38776386

  • Cancer Incidence After Diagnosis of Abdominal Aortic Aneurysm. Arteriosclerosis, thrombosis, and vascular biology Luo, L., Haas, A. M., Bell, C. F., Baylis, R. A., Adkar, S. S., Fu, C., Angelov, I., Giordano, S. H., Klarin, D., Leeper, N. J., Nead, K. T. 2024

    Abstract

    Epidemiological and mechanistic data support a potential causal link between cardiovascular disease (CVD) and cancer. Abdominal aortic aneurysms (AAAs) represent a common form of CVD with at least partially distinct genetic and biologic etiology from other forms of CVD. The risk of cancer and how this risk differs compared with other forms of CVD, is unknown among AAA patients. We conducted a retrospective cohort study using the IBM MarketScan Research Database to test whether individuals with AAA have a higher cancer risk independent of traditional shared risk factors.All individuals ≥18 years of age with ≥36 months of continuous coverage between 2008 and 2020 were enrolled. Those with potential Mendelian etiologies of AAA, aortic aneurysm with nonspecific anatomic location, or a cancer diagnosis before the start of follow-up were excluded. A subgroup analysis was performed of individuals having the Health Risk Assessment records including tobacco use and body mass index. The following groups of individuals were compared: (1) with AAA, (2) with non-AAA CVD, and (3) without any CVD.The propensity score-matched cohort included 58 993 individuals with AAA, 117 986 with non-AAA CVD, and 58 993 without CVD. The 5-year cumulative incidence of cancer was 13.1% (12.8%-13.5%) in participants with AAA, 10.1% (9.9%-10.3%) in participants with non-AAA CVD, and 9.6% (9.3%-9.9%) in participants without CVD. Multivariable-adjusted Cox proportional hazards regression models found that patients with AAA exhibited a higher cancer risk than either those with non-AAA CVD (hazard ratio, 1.28 [95% CI, 1.23-1.32]; P<0.001) or those without CVD (hazard ratio, 1.32 [95% CI, 1.26-1.38]; P<0.001). Results remained consistent after excluding common smoking-related cancers and when adjusting for tobacco use and body mass index.Patients with AAA may have a unique risk of cancer requiring further mechanistic study and investigation of the role of enhanced cancer screening.

    View details for DOI 10.1161/ATVBAHA.123.320543

    View details for PubMedID 38779853

  • Single-Cell Gene-Regulatory Networks of Advanced Symptomatic Atherosclerosis. Circulation research Mocci, G., Sukhavasi, K., Örd, T., Bankier, S., Singha, P., Arasu, U. T., Agbabiaje, O. O., Mäkinen, P., Ma, L., Hodonsky, C. J., Aherrahrou, R., Muhl, L., Liu, J., Gustafsson, S., Byandelger, B., Wang, Y., Koplev, S., Lendahl, U., Owens, G., Leeper, N. J., Pasterkamp, G., Vanlandewijck, M., Michoel, T., Ruusalepp, A., Hao, K., Ylä-Herttuala, S., Väli, M., Järve, H., Mokry, M., Civelek, M., Miller, C., Kovacic, J. C., Kaikkonen, M. U., Betsholtz, C., Björkegren, J. L. 2024

    Abstract

    While our understanding of the single-cell gene expression patterns underlying the transformation of vascular cell types during the progression of atherosclerosis is rapidly improving, the clinical and pathophysiological relevance of these changes remains poorly understood.Single-cell RNA sequencing data generated with SmartSeq2 (≈8000 genes/cell) in nearly 19 000 single cells isolated during atherosclerosis progression in Ldlr-/-Apob100/100 mice with human-like plasma lipoproteins and from humans with asymptomatic and symptomatic carotid plaques was clustered into multiple subtypes. For clinical and pathophysiological context, the advanced-stage and symptomatic subtype clusters were integrated with 135 tissue-specific (atherosclerotic aortic wall, mammary artery, liver, skeletal muscle, and visceral and subcutaneous, fat) gene-regulatory networks (GRNs) inferred from 600 coronary artery disease patients in the STARNET (Stockholm-Tartu Atherosclerosis Reverse Network Engineering Task) study.Advanced stages of atherosclerosis progression and symptomatic carotid plaques were largely characterized by 3 smooth muscle cells (SMCs), and 3 macrophage subtype clusters with extracellular matrix organization/osteogenic (SMC), and M1-type proinflammatory/Trem2-high lipid-associated (macrophage) phenotypes. Integrative analysis of these 6 clusters with STARNET revealed significant enrichments of 3 arterial wall GRNs: GRN33 (macrophage), GRN39 (SMC), and GRN122 (macrophage) with major contributions to coronary artery disease heritability and strong associations with clinical scores of coronary atherosclerosis severity (SYNTAX/Duke scores). The presence and pathophysiological relevance of GRN39 were verified in 5 independent RNAseq data sets obtained from the human coronary and aortic artery, and primary SMCs and by targeting its top-key drivers, FRZB and ALCAM, in cultured human vascular SMCs.By identifying and integrating the most gene-rich single-cell subclusters of atherosclerosis to date with a coronary artery disease framework of GRNs, GRN39 was identified and independently validated as being critical for the transformation of contractile SMCs into an osteogenic phenotype promoting advanced-stage, symptomatic atherosclerosis.

    View details for DOI 10.1161/CIRCRESAHA.123.323184

    View details for PubMedID 38639096

  • Computational protocol to identify shared transcriptional risks and mutually beneficial compounds between diseases. STAR protocols Gao, H., Zhang, M., Baylis, R. A., Wang, F., Björkegren, J. L., Kovacic, J. J., Ruusalepp, A., Leeper, N. J. 2024; 5 (1): 102883

    Abstract

    The accumulation of omics and biobank resources allows for a genome-wide understanding of the shared pathologic mechanisms between diseases and for strategies to identify drugs that could be repurposed as novel treatments. Here, we present a computational protocol, implemented as a Snakemake workflow, to identify shared transcriptional processes and screen compounds that could result in mutual benefit. This protocol also includes a description of a pharmacovigilance study designed to validate the effect of compounds using electronic health records. For complete details on the use and execution of this protocol, please refer to Gao et al.1 and Baylis et al.2.

    View details for DOI 10.1016/j.xpro.2024.102883

    View details for PubMedID 38354084

  • Generation of induced pluripotent stem cell line from a patient suffering from arterial calcification due to deficiency of CD73 (ACDC). Stem cell research Tripathi, D., Manhas, A., Noishiki, C., Wu, D., Adkar, S., Sallam, K., Fukaya, E., Leeper, N. J., Sayed, N. 2023; 75: 103285

    Abstract

    Arterial calcification due to deficiency of CD73 (ACDC) is an adult onset, rare genetic vascular disorder signified by calcium deposition in lower extremity arteries and joints of hands and feet. Mutations in NT5E gene has been shown to be responsible for the inactivation of enzyme CD73 causing calcium buildup. Here, we report a iPSC line generated from a patient showing signs of ACDC and carrying a missense mutation in NT5E (c.1126AG,p.T376A) gene. This iPSC line shows normal morphology, pluripotency, karyotype, and capability to differentiate into three germ layers, making it useful for disease modeling and investigating pathological mechanisms of ACDC.

    View details for DOI 10.1016/j.scr.2023.103285

    View details for PubMedID 38199067

  • Multi-ancestry genetic analysis of gene regulation in coronary arteries prioritizes disease risk loci. Cell genomics Hodonsky, C. J., Turner, A. W., Khan, M. D., Barrientos, N. B., Methorst, R., Ma, L., Lopez, N. G., Mosquera, J. V., Auguste, G., Farber, E., Ma, W. F., Wong, D., Onengut-Gumuscu, S., Kavousi, M., Peyser, P. A., van der Laan, S. W., Leeper, N. J., Kovacic, J. C., Björkegren, J. L., Miller, C. L. 2023: 100465

    Abstract

    Genome-wide association studies (GWASs) have identified hundreds of risk loci for coronary artery disease (CAD). However, non-European populations are underrepresented in GWASs, and the causal gene-regulatory mechanisms of these risk loci during atherosclerosis remain unclear. We incorporated local ancestry and haplotypes to identify quantitative trait loci for expression (eQTLs) and splicing (sQTLs) in coronary arteries from 138 ancestrally diverse Americans. Of 2,132 eQTL-associated genes (eGenes), 47% were previously unreported in coronary artery; 19% exhibited cell-type-specific expression. Colocalization revealed subgroups of eGenes unique to CAD and blood pressure GWAS. Fine-mapping highlighted additional eGenes, including TBX20 and IL5. We also identified sQTLs for 1,690 genes, among which TOR1AIP1 and ULK3 sQTLs demonstrated the importance of evaluating splicing to accurately identify disease-relevant isoform expression. Our work provides a patient-derived coronary artery eQTL resource and exemplifies the need for diverse study populations and multifaceted approaches to characterize gene regulation in disease processes.

    View details for DOI 10.1016/j.xgen.2023.100465

    View details for PubMedID 38190101

  • Role of vascular smooth muscle cell clonality in atherosclerosis. Frontiers in cardiovascular medicine Luo, L., Fu, C., Bell, C. F., Wang, Y., Leeper, N. J. 2023; 10: 1273596

    Abstract

    Atherosclerotic cardiovascular disease remains the leading cause of death worldwide. While many cell types contribute to the growing atherosclerotic plaque, the vascular smooth muscle cell (SMC) is a major contributor due in part to its remarkable plasticity and ability to undergo phenotype switching in response to injury. SMCs can migrate into the fibrous cap, presumably stabilizing the plaque, or accumulate within the lesional core, possibly accelerating vascular inflammation. How SMCs expand and react to disease stimuli has been a controversial topic for many decades. While early studies relying on X-chromosome inactivation were inconclusive due to low resolution and sensitivity, recent advances in multi-color lineage tracing models have revitalized the concept that SMCs likely expand in an oligoclonal fashion during atherogenesis. Current efforts are focused on determining whether all SMCs have equal capacity for clonal expansion or if a "stem-like" progenitor cell may exist, and to understand how constituents of the clone decide which phenotype they will ultimately adopt as the disease progresses. Mechanistic studies are also beginning to dissect the processes which confer cells with their overall survival advantage, test whether these properties are attributable to intrinsic features of the expanding clone, and define the role of cross-talk between proliferating SMCs and other plaque constituents such as neighboring macrophages. In this review, we aim to summarize the historical perspectives on SMC clonality, highlight unanswered questions, and identify translational issues which may need to be considered as therapeutics directed against SMC clonality are developed as a novel approach to targeting atherosclerosis.

    View details for DOI 10.3389/fcvm.2023.1273596

    View details for PubMedID 38089777

    View details for PubMedCentralID PMC10713728

  • Utilizing an induced pluripotent stem cell platform to model arterial calcification resulting from deficiency of CD73 Noishiki, C., Alsaigh, T., Wu, D., Adkar, S., Chandra, V., Klarin, D., Lee, J., Fukaya, E., Leeper, N., Sayed, N. SAGE PUBLICATIONS LTD. 2023: 499-500
  • Identifying shared transcriptional risk patterns between atherosclerosis and cancer. iScience Baylis, R. A., Gao, H., Wang, F., Bell, C. F., Luo, L., Björkegren, J. L., Leeper, N. J. 2023; 26 (9): 107513

    Abstract

    Cancer and cardiovascular disease (CVD) are the leading causes of death worldwide. Numerous overlapping pathophysiologic mechanisms have been hypothesized to drive the development of both diseases. Further investigation of these common pathways could allow for the identification of mutually detrimental processes and therapeutic targeting to derive mutual benefit. In this study, we intersect transcriptomic datasets correlated with disease severity or patient outcomes for both cancer and atherosclerotic CVD. These analyses confirmed numerous pathways known to underlie both diseases, such as inflammation and hypoxia, but also identified several novel shared pathways. We used these to explore common translational targets by applying the drug prediction software, OCTAD, to identify compounds that simultaneously reverse the gene expression signature for both diseases. These analyses suggest that certain tumor-specific therapeutic approaches may be implemented so that they avoid cardiovascular consequences, and in some cases may even be used to simultaneously target co-prevalent cancer and atherosclerosis.

    View details for DOI 10.1016/j.isci.2023.107513

    View details for PubMedID 37636064

    View details for PubMedCentralID PMC10448075

  • Combined near infrared photoacoustic imaging and ultrasound detects vulnerable atherosclerotic plaque. Biomaterials Schneider, M. K., Wang, J., Kare, A., Adkar, S. S., Salmi, D., Bell, C. F., Alsaigh, T., Wagh, D., Coller, J., Mayer, A., Snyder, S. J., Borowsky, A. D., Long, S. R., Lansberg, M. G., Steinberg, G. K., Heit, J. J., Leeper, N. J., Ferrara, K. W. 2023; 302: 122314

    Abstract

    Atherosclerosis is an inflammatory process resulting in the deposition of cholesterol and cellular debris, narrowing of the vessel lumen and clot formation. Characterization of the morphology and vulnerability of the lesion is essential for effective clinical management. Here, near-infrared auto-photoacoustic (NIRAPA) imaging is shown to detect plaque components and, when combined with ultrasound imaging, to differentiate stable and vulnerable plaque. In an ex vivo study of photoacoustic imaging of excised plaque from 25 patients, 88.2% sensitivity and 71.4% specificity were achieved using a clinically-relevant protocol. In order to determine the origin of the NIRAPA signal, immunohistochemistry, spatial transcriptomics and spatial proteomics were co-registered with imaging and applied to adjacent plaque sections. The highest NIRAPA signal was spatially correlated with bilirubin and associated blood-based residue and with the cytoplasmic contents of inflammatory macrophages bearing CD74, HLA-DR, CD14 and CD163 markers. In summary, we establish the potential to apply the NIRAPA-ultrasound imaging combination to detect vulnerable carotid plaque and a methodology for fusing molecular imaging with spatial transcriptomic and proteomic methods.

    View details for DOI 10.1016/j.biomaterials.2023.122314

    View details for PubMedID 37776766

  • A Glimpse Into the Black Box: Using Machine Learning to Prioritize Predictors of Vascular Disease. JACC. Advances Leeper, N. J., Adkar, S. S. 2023; 2 (7): 100563

    View details for DOI 10.1016/j.jacadv.2023.100563

    View details for PubMedID 38939483

    View details for PubMedCentralID PMC11198632

  • Spatial Metabolomics and the Vulnerable Atherosclerotic Plaque. Arteriosclerosis, thrombosis, and vascular biology Luo, L., Leeper, N. J. 2023

    View details for DOI 10.1161/ATVBAHA.123.319739

    View details for PubMedID 37534466

  • Leukocytes carrying Clonal Hematopoiesis of Indeterminate Potential (CHIP) Mutations invade Human Atherosclerotic Plaques. medRxiv : the preprint server for health sciences von Scheidt, M., Bauer, S., Ma, A., Hao, K., Kessler, T., Vilne, B., Wang, Y., Hodonsky, C. J., Ghosh, S. K., Mokry, M., Gao, H., Kawai, K., Sakamoto, A., Kaiser, J., Bongiovanni, D., Fleig, J., Oldenbuettel, L., Chen, Z., Moggio, A., Sager, H. B., Hecker, J. S., Bassermann, F., Maegdefessel, L., Miller, C. L., Koenig, W., Zeiher, A. M., Dimmeler, S., Graw, M., Braun, C., Ruusalepp, A., Leeper, N. J., Kovacic, J. C., Björkegren, J. L., Schunkert, H. 2023

    Abstract

    Leukocyte progenitors derived from clonal hematopoiesis of undetermined potential (CHIP) are associated with increased cardiovascular events. However, the prevalence and functional relevance of CHIP in coronary artery disease (CAD) are unclear, and cells affected by CHIP have not been detected in human atherosclerotic plaques.CHIP mutations in blood and tissues were identified by targeted deep-DNA-sequencing (DNAseq: coverage >3,000) and whole-genome-sequencing (WGS: coverage >35). CHIP-mutated leukocytes were visualized in human atherosclerotic plaques by mutaFISH™. Functional relevance of CHIP mutations was studied by RNAseq.DNAseq of whole blood from 540 deceased CAD patients of the Munich cardIovaScular StudIes biObaNk (MISSION) identified 253 (46.9%) CHIP mutation carriers (mean age 78.3 years). DNAseq on myocardium, atherosclerotic coronary and carotid arteries detected identical CHIP mutations in 18 out of 25 mutation carriers in tissue DNA. MutaFISH™ visualized individual macrophages carrying DNMT3A CHIP mutations in human atherosclerotic plaques. Studying monocyte-derived macrophages from Stockholm-Tartu Atherosclerosis Reverse Networks Engineering Task (STARNET; n=941) by WGS revealed CHIP mutations in 14.2% (mean age 67.1 years). RNAseq of these macrophages revealed that expression patterns in CHIP mutation carriers differed substantially from those of non-carriers. Moreover, patterns were different depending on the underlying mutations, e.g. those carrying TET2 mutations predominantly displayed upregulated inflammatory signaling whereas ASXL1 mutations showed stronger effects on metabolic pathways.Deep-DNA-sequencing reveals a high prevalence of CHIP mutations in whole blood of CAD patients. CHIP-affected leukocytes invade plaques in human coronary arteries. RNAseq data obtained from macrophages of CHIP-affected patients suggest that pro-atherosclerotic signaling differs depending on the underlying mutations. Further studies are necessary to understand whether specific pathways affected by CHIP mutations may be targeted for personalized treatment.

    View details for DOI 10.1101/2023.07.22.23292754

    View details for PubMedID 37546840

    View details for PubMedCentralID PMC10402238

  • Transcriptomic-based clustering of human atherosclerotic plaques identifies subgroups with different underlying biology and clinical presentation. Nature cardiovascular research Mokry, M., Boltjes, A., Slenders, L., Bel-Bordes, G., Cui, K., Brouwer, E., Mekke, J. M., Depuydt, M. A., Timmerman, N., Waissi, F., Verwer, M. C., Turner, A. W., Khan, M. D., Hodonsky, C. J., Benavente, E. D., Hartman, R. J., van den Dungen, N. A., Lansu, N., Nagyova, E., Prange, K. H., Kovacic, J. C., Bjorkegren, J. L., Pavlos, E., Andreakos, E., Schunkert, H., Owens, G. K., Monaco, C., Finn, A. V., Virmani, R., Leeper, N. J., de Winther, M. P., Kuiper, J., de Borst, G. J., Stroes, E. S., Civelek, M., de Kleijn, D. P., den Ruijter, H. M., Asselbergs, F. W., van der Laan, S. W., Miller, C. L., Pasterkamp, G. 2022; 1 (12): 1140-1155

    Abstract

    Histopathological studies have revealed key processes of atherosclerotic plaque thrombosis. However, the diversity and complexity of lesion types highlight the need for improved sub-phenotyping. Here we analyze the gene expression profiles of 654 advanced human carotid plaques. The unsupervised, transcriptome-driven clustering revealed five dominant plaque types. These plaque phenotypes were associated with clinical presentation and showed differences in cellular compositions. Validation in coronary segments showed that the molecular signature of these plaques was linked to coronary ischemia. One of the plaque types with the most severe clinical symptoms pointed to both inflammatory and fibrotic cell lineages. Further, we did a preliminary analysis of potential circulating biomarkers that mark the different plaques phenotypes. In conclusion, the definition of the plaque at risk for a thrombotic event can be fine-tuned by in-depth transcriptomic-based phenotyping. These differential plaque phenotypes prove clinically relevant for both carotid and coronary artery plaques and point to distinct underlying biology of symptomatic lesions.

    View details for DOI 10.1038/s44161-022-00171-0

    View details for PubMedID 37920851

  • Single-nucleus chromatin accessibility profiling highlights regulatory mechanisms of coronary artery disease risk. Nature genetics Turner, A. W., Hu, S. S., Mosquera, J. V., Ma, W. F., Hodonsky, C. J., Wong, D., Auguste, G., Song, Y., Sol-Church, K., Farber, E., Kundu, S., Kundaje, A., Lopez, N. G., Ma, L., Ghosh, S. K., Onengut-Gumuscu, S., Ashley, E. A., Quertermous, T., Finn, A. V., Leeper, N. J., Kovacic, J. C., Björkgren, J. L., Zang, C., Miller, C. L. 2022

    Abstract

    Coronary artery disease (CAD) is a complex inflammatory disease involving genetic influences across cell types. Genome-wide association studies have identified over 200 loci associated with CAD, where the majority of risk variants reside in noncoding DNA sequences impacting cis-regulatory elements. Here, we applied single-nucleus assay for transposase-accessible chromatin with sequencing to profile 28,316 nuclei across coronary artery segments from 41 patients with varying stages of CAD, which revealed 14 distinct cellular clusters. We mapped ~320,000 accessible sites across all cells, identified cell-type-specific elements and transcription factors, and prioritized functional CAD risk variants. We identified elements in smooth muscle cell transition states (for example, fibromyocytes) and functional variants predicted to alter smooth muscle cell- and macrophage-specific regulation of MRAS (3q22) and LIPA (10q23), respectively. We further nominated key driver transcription factors such as PRDM16 and TBX2. Together, this single-nucleus atlas provides a critical step towards interpreting regulatory mechanisms across the continuum of CAD risk.

    View details for DOI 10.1038/s41588-022-01069-0

    View details for PubMedID 35590109

  • Killing the two deadly birds of atherosclerosis and cancer with one stone NATURE CARDIOVASCULAR RESEARCH Bell, C. F., Leeper, N. J. 2022; 1 (5): 403-404
  • Killing the two deadly birds of atherosclerosis and cancer with one stone. Nature cardiovascular research Bell, C. F., Leeper, N. J. 2022; 1 (5): 403-404

    View details for DOI 10.1038/s44161-022-00068-y

    View details for PubMedID 39195942

  • 2021 Jeffrey M. Hoeg Award Lecture: Defining the Role of Efferocytosis in Cardiovascular Disease: A Focus on the CD47 (Cluster of Differentiation 47) Axis. Arteriosclerosis, thrombosis, and vascular biology Jarr, K., Kojima, Y., Weissman, I. L., Leeper, N. J. 2022: 101161ATVBAHA122317049

    Abstract

    A key feature of atherogenesis is the accumulation of diseased and dying cells within the lesional necrotic core. While the burden of intraplaque apoptotic cells may be driven in part by an increase in programmed cell death, mounting evidence suggests that their presence may primarily be dictated by a defect in programmed cell removal, or efferocytosis. In this brief review, we will summarize the evidence suggesting that inflammation-dependent changes within the plaque render target cells inedible and reduce the appetite of lesional phagocytes. We will present the genetic causation studies, which indicate these phenomena promote lesion expansion and plaque vulnerability, and the interventional data which suggest that these processes can be reversed. Particular emphasis is provided related to the antiphagocytic CD47 (cluster of differentiation 47) do not eat me axis, which has emerged as a novel antiatherosclerotic translational target that is predicted to provide benefit independent of traditional cardiovascular risk factors.

    View details for DOI 10.1161/ATVBAHA.122.317049

    View details for PubMedID 35387480

  • Plaque Evaluation by Ultrasound and Transcriptomics Reveals BCLAF1 as a Regulator of Smooth Muscle Cell Lipid Transdifferentiation in Atherosclerosis. Arteriosclerosis, thrombosis, and vascular biology Rykaczewska, U., Zhao, Q., Saliba-Gustafsson, P., Lengquist, M., Kronqvist, M., Bergman, O., Huang, Z., Lund, K., Waden, K., Pons, V. Z., Caidahl, K., Skogsberg, J., Vukojevic, V., Lindeman, J. H., Roy, J., Hansson, G. K., Treuter, E., Leeper, N. J., Eriksson, P., Ehrenborg, E., Razuvaev, A., Hedin, U., Matic, L. 2022: ATVBAHA121317018

    Abstract

    BACKGROUND: Understanding the processes behind carotid plaque instability is necessary to develop methods for identification of patients and lesions with stroke risk. Here, we investigated molecular signatures in human plaques stratified by echogenicity as assessed by duplex ultrasound.METHODS: Lesion echogenicity was correlated to microarray gene expression profiles from carotid endarterectomies (n=96). The findings were extended into studies of human and mouse atherosclerotic lesions in situ, followed by functional investigations in vitro in human carotid smooth muscle cells (SMCs).RESULTS: Pathway analyses highlighted muscle differentiation, iron homeostasis, calcification, matrix organization, cell survival balance, and BCLAF1 (BCL2 [B-cell lymphoma 2]-associated transcription factor 1) as the most significant signatures. BCLAF1 was downregulated in echolucent plaques, positively correlated to proliferation and negatively to apoptosis. By immunohistochemistry, BCLAF1 was found in normal medial SMCs. It was repressed early during atherogenesis but reappeared in CD68+ cells in advanced plaques and interacted with BCL2 by proximity ligation assay. In cultured SMCs, BCLAF1 was induced by differentiation factors and mitogens and suppressed by macrophage-conditioned medium. BCLAF1 silencing led to downregulation of BCL2 and SMC markers, reduced proliferation, and increased apoptosis. Transdifferentiation of SMCs by oxLDL was accompanied by upregulation of BCLAF1, CD36, and CD68, while oxLDL exposure with BCLAF1 silencing preserved MYH (myosin heavy chain) 11 expression and prevented transdifferentiation. BCLAF1 was associated with expression of cell differentiation, contractility, viability, and inflammatory genes, as well as the scavenger receptors CD36 and CD68. BCLAF1 expression in CD68+/BCL2+ cells of SMC origin was verified in plaques from MYH11 lineage-tracing atherosclerotic mice. Moreover, BCLAF1 downregulation associated with vulnerability parameters and cardiovascular risk in patients with carotid atherosclerosis.CONCLUSIONS: Plaque echogenicity correlated with enrichment of distinct molecular pathways and identified BCLAF1, previously not described in atherosclerosis, as the most significant gene. Functionally, BCLAF1 seems necessary for survival and transdifferentiation of SMCs into a macrophage-like phenotype. The role of BCLAF1 in plaque vulnerability should be further evaluated.

    View details for DOI 10.1161/ATVBAHA.121.317018

    View details for PubMedID 35321563

  • Development of a polygenic risk score to improve detection of peripheral artery disease. Vascular medicine (London, England) Wang, F., Ghanzouri, I., Leeper, N. J., Tsao, P. S., Ross, E. G. 2022: 1358863X211067564

    Abstract

    INTRODUCTION: Peripheral artery disease (PAD) is a major cause of cardiovascular morbidity and mortality, yet timely diagnosis is elusive. Larger genome-wide association studies (GWAS) have now provided the ability to evaluate whether genetic data, in the form of genome-wide polygenic risk scores (PRS), can help improve our ability to identify patients at high risk of having PAD.METHODS: Using summary statistic data from the largest PAD GWAS from the Million Veteran Program, we developed PRSs with genome data from UK Biobank. We then evaluated the clinical utility of adding the best-performing PRS to a PAD clinical risk score.RESULTS: A total of 487,320 participants (5759 PAD cases) were included in our final genetic analysis. Compared to participants in the lowest 10% of PRS, those in the highest decile had 3.1 higher odds of having PAD (95% CI, 3.06-3.21). Additionally, a PAD PRS was associated with increased risk of having coronary artery disease, congestive heart failure, and cerebrovascular disease. The PRS significantly improved a clinical risk model (Net Reclassification Index = 0.07, p < 0.001), with most of the performance seen in downgrading risk of controls. Combining clinical and genetic data to detect risk of PAD resulted in a model with an area under the curve of 0.76 (95% CI, 0.75-0.77).CONCLUSION: We demonstrate that a genome-wide PRS can discriminate risk of PAD and other cardiovascular diseases. Adding a PAD PRS to clinical risk models may help improve detection of prevalent, but undiagnosed disease.

    View details for DOI 10.1177/1358863X211067564

    View details for PubMedID 35287516

  • Prevention of arterial and venous thrombotic events in symptomatic peripheral arterial disease patients after lower extremity revascularization in the VOYAGER PAD trial: Dual anticoagulant/antiplatelet regimen vs antiplatelet therapy alone. Journal of thrombosis and haemostasis : JTH Berkowitz, S. D., Bauersachs, R. M., Szarek, M., Nehler, M. R., Debus, E. S., Patel, M. R., Anand, S. S., Capell, W. H., Hess, C. N., Hsia, J., Leeper, N. J., Brasil, D., Mátyás, L., Diaz, R., Brodmann, M., Muehlhofer, E., Haskell, L., Bonaca, M. P. 2022

    Abstract

    Vascular disease burden after lower extremity revascularization (LER) comprises more than the first event, more vascular beds than the local arteries, and more than one clinical event type.Assess total arterial and venous thrombotic burden after LER for symptomatic peripheral artery disease (PAD) and effect of low-dose anticoagulation added to low-dose antiplatelet therapy.VOYAGER PAD randomized 6,564 symptomatic PAD patients undergoing LER to rivaroxaban 2.5 mg twice-daily or placebo on aspirin background. Marginal proportional-hazards models used to generate treatment hazard ratios and associated 95% CIs for first and total events; non-thrombotic deaths treated as competing terminal events. Incidence rates calculated as number of events per 100 patient-years follow-up.Over 2.5 years (median), first and total thrombotic event rates: 7.1 and 10.3 events/100 patient-years, respectively, in placebo group. Two-thirds (925/1,372) of total thrombotic events (arterial 95%, venous 5%) were nonfatal first events. Nearly 1/3 of patients with first event had a second arterial or venous thrombotic event. Rivaroxaban plus aspirin reduced first and total arterial and venous thrombotic events to 5.4 and 7.9 events/100 patient-years, respectively, a reduction in total thrombotic events over aspirin of 23% (HR 0.77, 95%CI 0.67-0.89, p=0.0005), preventing 6.1 total arterial and venous thrombotic events at 3 years.Assessing total arterial and venous thrombotic events, not just first events, provides more complete information about disease burden and absolute on-treatment impact. Following LER, judicious modulation of more than one coagulation pathway can provide broader benefit than intensifying inhibition of one hemostatic system component.

    View details for DOI 10.1111/jth.15673

    View details for PubMedID 35170216

  • Unsupervised Learning for Automated Detection of Coronary Artery Disease Subgroups. Journal of the American Heart Association Flores, A. M., Schuler, A., Eberhard, A. V., Olin, J. W., Cooke, J. P., Leeper, N. J., Shah, N. H., Ross, E. G. 2021: e021976

    Abstract

    Background The promise of precision population health includes the ability to use robust patient data to tailor prevention and care to specific groups. Advanced analytics may allow for automated detection of clinically informative subgroups that account for clinical, genetic, and environmental variability. This study sought to evaluate whether unsupervised machine learning approaches could interpret heterogeneous and missing clinical data to discover clinically important coronary artery disease subgroups. Methods and Results The Genetic Determinants of Peripheral Arterial Disease study is a prospective cohort that includes individuals with newly diagnosed and/or symptomatic coronary artery disease. We applied generalized low rank modeling and K-means cluster analysis using 155 phenotypic and genetic variables from 1329 participants. Cox proportional hazard models were used to examine associations between clusters and major adverse cardiovascular and cerebrovascular events and all-cause mortality. We then compared performance of risk stratification based on clusters and the American College of Cardiology/American Heart Association pooled cohort equations. Unsupervised analysis identified 4 phenotypically and prognostically distinct clusters. All-cause mortality was highest in cluster 1 (oldest/most comorbid; 26%), whereas major adverse cardiovascular and cerebrovascular event rates were highest in cluster 2 (youngest/multiethnic; 41%). Cluster 4 (middle-aged/healthiest behaviors) experienced more incident major adverse cardiovascular and cerebrovascular events (30%) than cluster 3 (middle-aged/lowest medication adherence; 23%), despite apparently similar risk factor and lifestyle profiles. In comparison with the pooled cohort equations, cluster membership was more informative for risk assessment of myocardial infarction, stroke, and mortality. Conclusions Unsupervised clustering identified 4 unique coronary artery disease subgroups with distinct clinical trajectories. Flexible unsupervised machine learning algorithms offer the ability to meaningfully process heterogeneous patient data and provide sharper insights into disease characterization and risk assessment. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00380185.

    View details for DOI 10.1161/JAHA.121.021976

    View details for PubMedID 34845917

  • Dynamic changes in chromatin accessibility are associated with the atherogenic transitioning of vascular smooth muscle cells. Cardiovascular research Wang, Y., Gao, H., Wang, F., Ye, Z., Mokry, M., Turner, A. W., Ye, J., Koplev, S., Luo, L., Alsaigh, T., Adkar, S. S., Elishaev, M., Gao, X., Maegdefessel, L., Bjorkegren, J. L., Pasterkamp, G., Miller, C. L., Ross, E. G., Leeper, N. J. 2021

    Abstract

    AIMS: De-differentiation and activation of pro-inflammatory pathways are key transitions vascular smooth muscle cells (SMCs) make during atherogenesis. Here, we explored the upstream regulators of this 'atherogenic transition'.METHODS AND RESULTS: Genome-wide sequencing studies, including ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) and RNA-seq, were performed on cells isolated from both murine SMC-lineage tracing models of atherosclerosis and human atherosclerotic lesions. At the bulk level, alterations in chromatin accessibility were associated with the atherogenic transitioning of lesional SMCs, especially in relation to genes that govern differentiation status and complement-dependent inflammation. Using computational biology, we observed that a transcription factor previously related to coronary artery disease, ATF3 (Activating transcription factor 3), was predicted to be an upstream regulator of genes altered during the transition. At the single-cell level, our results indicated that ATF3 is a key repressor of SMC transitioning towards the subset of cells that promote vascular inflammation by activating the complement cascade. The expression of ATF3 and complement component C3 were negatively correlated in SMCs from human atherosclerotic lesions, suggesting translational relevance. Phenome-wide association studies indicated that genetic variation that results in reduced expression of ATF3 is correlated with an increased risk for atherosclerosis, and the expression of ATF3 was significantly downregulated in humans with advanced vascular disease.CONCLUSION: Our study indicates that the plasticity of atherosclerotic SMCs may in part be explained by dynamic changes in their chromatin architecture, which in turn may contribute to their maladaptive response to inflammation-induced stress.TRANSLATIONAL PERSPECTIVE: The recent CANTOS and COLCOT trials have shown that targeting inflammatory pathways lowers the risk of major adverse cardiovascular events. However, more specific targets are needed to avoid immunosuppressive side effects. Our data identify an upstream regulator of pro-inflammatory SMCs, ATF3, which is involved in the initial atherogenic transitioning of lesional SMCs. Restoring ATF3 activity may prevent the de-differentiation of SMCs and offer a novel translational approach for the suppression of complement-dependent inflammation in atherosclerotic lesions.

    View details for DOI 10.1093/cvr/cvab347

    View details for PubMedID 34849613

  • Macrophage LRP1 (Low-Density Lipoprotein Receptor-Related Protein 1) Is Required for the Effect of CD47 Blockade on Efferocytosis and Atherogenesis. Arteriosclerosis, thrombosis, and vascular biology Mueller, P. A., Kojima, Y., Huynh, K. T., Maldonado, R. A., Ye, J., Tavori, H., Pamir, N., Leeper, N. J., Fazio, S. 2021: ATVBAHA121316854

    Abstract

    OBJECTIVE: Antibody blockade of the do not eat me signal CD47 enhances efferocytosis and reduces lesion size and necrotic core formation in murine atherosclerosis. TNF (Tumor necrosis factor)-alpha expression directly enhances CD47 expression, and elevated TNF-alpha is observed in the absence of the proefferocytosis receptor LRP1 (low-density lipoprotein receptor-related protein 1), a regulator of atherogenesis and inflammation. Thus, we tested the hypothesis that CD47 blockade requires the presence of macrophage LRP1 to enhance efferocytosis, temper TNF-alpha-dependent inflammation, and limit atherosclerosis. Approach and Results: Mice lacking systemic apoE (apoE-/-), alone or in combination with the loss of macrophage LRP1 (double knockout), were fed a Western-type diet for 12 weeks while receiving anti-CD47 antibody (anti-CD47) or IgG every other day. In apoE-/- mice, treatment with anti-CD47 reduced lesion size by 25.4%, decreased necrotic core area by 34.5%, and decreased the ratio of free:macrophage-associated apoptotic bodies by 47.6% compared with IgG controls (P<0.05), confirming previous reports. Double knockout mice treated with anti-CD47 showed no differences in lesion size, necrotic core area, or the ratio of free:macrophage-associated apoptotic bodies compared with IgG controls. In vitro efferocytosis was 30% higher when apoE-/- phagocytes were incubated with anti-CD47 compared with IgG controls (P<0.05); however, anti-CD47 had no effect on efferocytosis in double knockout phagocytes. Analyses of mRNA and protein showed increased CD47 expression in anti-inflammatory IL (interleukin)-4 treated LRP1-/- macrophages compared with wild type, but no differences were observed in inflammatory lipopolysaccharide-treated macrophages.CONCLUSIONS: The proefferocytosis receptor LRP1 in macrophages is necessary for anti-CD47 blockade to enhance efferocytosis, limit atherogenesis, and decrease necrotic core formation in the apoE-/- model of atherosclerosis.

    View details for DOI 10.1161/ATVBAHA.121.316854

    View details for PubMedID 34758632

  • Ultra-selective carbon nanotubes for photoacoustic imaging of inflamed atherosclerotic plaques. Advanced functional materials Gifani, M., Eddins, D. J., Kosuge, H., Zhang, Y., Paluri, S. L., Larson, T., Leeper, N., Herzenberg, L. A., Gambhir, S. S., McConnell, M. V., Ghosn, E. E., Smith, B. R. 2021; 31 (37)

    Abstract

    Disruption of vulnerable atherosclerotic plaques often leads to myocardial infarction and stroke, the leading causes of morbidity and mortality in the United States. A diagnostic method that detects high-risk atherosclerotic plaques at early stages could prevent these sequelae. The abundance of immune cells in the arterial wall, especially inflammatory Ly-6Chi monocytes and foamy macrophages, is indicative of plaque‎ inflammation, and may be associated with plaque vulnerability. Hence, we sought to develop a new method that specifically targets these immune cells to offer clinically-relevant diagnostic information about cardiovascular disease. We combine ultra-selective nanoparticle targeting of Ly-6Chi monocytes and foamy macrophages with clinically-viable photoacoustic imaging (PAI) in order to precisely and specifically image inflamed plaques ex vivo in a mouse model that mimics human vulnerable plaques histopathologically. Within the plaques, high-dimensional single-cell flow cytometry (13-parameter) showed that our nanoparticles were almost-exclusively taken up by the Ly-6Chi monocytes and foamy macrophages that heavily infiltrate plaques. PAI identified inflamed atherosclerotic plaques that display ~6-fold greater signal compared to controls (P<0.001) six hours after intravenous injection of ultra-selective carbon nanotubes, with in vivo corroboration via optical imaging. Our highly selective strategy may provide a targeted, non-invasive imaging strategy to accurately identify and diagnose inflamed atherosclerotic lesions.

    View details for DOI 10.1002/adfm.202101005

    View details for PubMedID 34733130

    View details for PubMedCentralID PMC8559995

  • Ultraselective Carbon Nanotubes for Photoacoustic Imaging of Inflamed Atherosclerotic Plaques ADVANCED FUNCTIONAL MATERIALS Gifani, M., Eddins, D. J., Kosuge, H., Zhang, Y., Paluri, S. A., Larson, T., Leeper, N., Herzenberg, L. A., Gambhir, S., McConnell, M., Ghosn, E. B., Smith, B. 2021
  • Peripheral Vascular Disease in 2021. Circulation research Leeper, N. J., Hamburg, N. M. 2021; 128 (12): 1803-1804

    View details for DOI 10.1161/CIRCRESAHA.121.319562

    View details for PubMedID 34110903

  • Leveraging Machine Learning and Artificial Intelligence to Improve Peripheral Artery Disease Detection, Treatment, and Outcomes. Circulation research Flores, A. M., Demsas, F., Leeper, N. J., Ross, E. G. 2021; 128 (12): 1833-1850

    Abstract

    Peripheral artery disease is an atherosclerotic disorder which, when present, portends poor patient outcomes. Low diagnosis rates perpetuate poor management, leading to limb loss and excess rates of cardiovascular morbidity and death. Machine learning algorithms and artificially intelligent systems have shown great promise in application to many areas in health care, such as accurately detecting disease, predicting patient outcomes, and automating image interpretation. Although the application of these technologies to peripheral artery disease are in their infancy, their promises are tremendous. In this review, we provide an introduction to important concepts in the fields of machine learning and artificial intelligence, detail the current state of how these technologies have been applied to peripheral artery disease, and discuss potential areas for future care enhancement with advanced analytics.

    View details for DOI 10.1161/CIRCRESAHA.121.318224

    View details for PubMedID 34110911

  • Comparison of Pre-Amputation Evaluation in Patients with and without Chronic Kidney Disease. American journal of nephrology Subramanian, N., Han, J., Leeper, N. J., Ross, E. G., Montez-Rath, M. E., Chang, T. I. 2021: 1–8

    Abstract

    INTRODUCTION: Patients with chronic kidney disease (CKD) and peripheral artery disease (PAD) are more likely to undergo lower extremity amputation than patients with preserved kidney function. We sought to determine whether patients with CKD were less likely to receive pre-amputation care in the 1-year prior to lower extremity amputation compared to patients without CKD.METHODS: We conducted a retrospective observational study of patients with PAD-related lower extremity amputation between January 2014 and December 2017 using a large commercial insurance database. The primary exposure was CKD identified using billing codes and laboratory values. The primary outcomes were receipt of pre-amputation care, defined as diagnostic evaluation (ankle-brachial index, duplex ultrasound, and computed tomographic angiography), specialty care (vascular surgery, cardiology, orthopedic surgery, and podiatry), and lower extremity revascularization in the 1-year prior to amputation. We conducted separate logistic regression models to estimate the adjusted odds ratio (aOR) and 95% confidence intervals (CIs) among patients with and without CKD. We assessed for effect modification by age, sex, Black race, and diabetes status.RESULTS: We identified 8,554 patients with PAD-related amputation. In fully adjusted models, patients with CKD were more likely to receive diagnostic evaluation (aOR 1.30; 95% CI 1.17-1.44) and specialty care (aOR 1.45, 95% CI 1.27-1.64) in the 1-year prior to amputation. There was no difference in odds of revascularization by CKD status (aOR 1.03, 0.90-1.19). Age, sex, Black race, and diabetes status did not modify these associations.DISCUSSION/CONCLUSION: Patients with CKD had higher odds of receiving diagnostic testing and specialty care and similar odds of lower extremity revascularization in the 1-year prior to amputation than patients without CKD. Disparities in access to pre-amputation care do not appear to explain the higher amputation rates seen among patients with CKD.

    View details for DOI 10.1159/000516017

    View details for PubMedID 33957619

  • US National Trends in Vascular Surgical Practice During the COVID-19 Pandemic. JAMA surgery Ho, V. T., Eberhard, A. V., Asch, S. M., Leeper, N. J., Fukaya, E., Arya, S., Ross, E. G. 2021

    View details for DOI 10.1001/jamasurg.2021.1708

    View details for PubMedID 33856428

  • 2021 ACC/AHA/SVM/ACP Advanced Training Statement on Vascular Medicine (Revision of the 2004 ACC/ACP/SCAI/SVMB/SVS Clinical Competence Statement on Vascular Medicine and Catheter-Based Peripheral Vascular Interventions) JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Creager, M. A., Hamburg, N. M., Calligaro, K. D., Casanegra, A., Freeman, R., Gordon, P. A., Gornik, H. L., Kim, E. H., Leeper, N. J., Merli, G. J., Niazi, K., Olin, J. W., Quiroz, R., Kaso, E., Wasan, S., Waxler, A. R., White, C. J., Solaru, K., Williams, M. S., ACC Competency Management Comm 2021; 77 (7): 998–1020
  • 2021 ACC/AHA/SVM/ACP Advanced Training Statement on Vascular Medicine (Revision of the 2004 ACC/ACP/SCAI/SVMB/SVS Clinical Competence Statement on Vascular Medicine and Catheter-Based Peripheral Vascular Interventions) A Report of the ACC Competency Management Committee CIRCULATION-CARDIOVASCULAR INTERVENTIONS Creager, M. A., Hamburg, N. M., Calligaro, K. D., Casanegra, A., Freeman, R., Gordon, P. A., Gornik, H. L., Kim, E. H., Leeper, N. J., Merli, G. J., Niazi, K., Olin, J. W., Quiroz, R., Kaso, E., Wasan, S., Waxler, A. R., White, C. J., Solaru, K., Williams, M. S. 2021; 14 (2): e000079

    View details for DOI 10.1161/HCV.0000000000000079

    View details for Web of Science ID 000639305500001

    View details for PubMedID 33448231

  • 2021 ACC/AHA/SVM/ACP Advanced Training Statement on Vascular Medicine (Revision of the 2004 ACC/ACP/SCAI/SVMB/SVS Clinical Competence Statement on Vascular Medicine and Catheter-Based Peripheral Vascular Interventions) VASCULAR MEDICINE Creager, M. A., Hamburg, N. M., Calligaro, K. D., Casanegra, A., Freeman, R., Gordon, P. A., Gornik, H. L., Kim, E. H., Leeper, N. J., Merli, G. J., Niazi, K., Olin, J. W., Quiroz, R., Kaso, E., Wasan, S., Waxler, A. R., White, C. J., Solaru, K., Williams, M. S., Arrighi, J. A., Mendes, L. A., Day, J., Dec, G., Denktas, A., Drajpuch, D., Fernandes, S., Francis, S. A., Hahn, R. T., Housholder-Hughes, S. D., Khan, S. S., Klarich, K., Kondapaneni, M., Lee, K. S., Lin, C., Marine, J. E., McConnaughey, S., Ryan, T., Silvestry, F. E., Solomon, M. A., Spicer, R. L., Wang, A., Weissman, G., Weitz, H. H., ACC Competency Management Comm, Assoc Black Cardiologists, Soc Cardiovasc Angiography Interve, Soc Vasc Nursing, Soc Vasc Surg 2021: 91–112

    View details for DOI 10.1177/1358863X20987551

    View details for Web of Science ID 000618412700001

    View details for PubMedID 33448240

  • Chitinase 3 like 1 (CHI3L1) is a regulator of smooth muscle cell physiology and atherosclerotic lesion stability. Cardiovascular research Tsantilas, P. n., Lao, S. n., Wu, Z. n., Eberhard, A. n., Winski, G. n., Vaerst, M. n., Nanda, V. n., Wang, Y. n., Kojima, Y. n., Ye, J. n., Flores, A. n., Jarr, K. U., Pelisek, J. n., Eckstein, H. H., Matic, L. n., Hedin, U. n., Tsao, P. S., Paloschi, V. n., Maegdefessel, L. n., Leeper, N. J. 2021

    Abstract

    Atherosclerotic cerebrovascular disease underlies the majority of ischemic strokes and is a major cause of death and disability. While plaque burden is a predictor of adverse outcomes, plaque vulnerability is increasingly recognized as a driver of lesion rupture and risk for clinical events. Defining the molecular regulators of carotid instability could inform the development of new biomarkers and/or translational targets for at-risk individuals.Using two independent human endarterectomy biobanks, we found that the understudied glycoprotein, Chitinase 3 like 1 (CHI3L1), is upregulated in patients with carotid disease compared to healthy controls. Further, CHI3L1 levels were found to stratify individuals based on symptomatology and histopathological evidence of an unstable fibrous cap. Gain- and loss-of-function studies in cultured human carotid artery smooth muscle cells (SMCs) showed that CHI3L1 prevents a number of maladaptive changes in that cell type, including phenotype switching towards a synthetic and hyperproliferative state. Using two murine models of carotid remodelling and lesion vulnerability, we found that knockdown of Chil1 resulted in larger neointimal lesions comprised by de-differentiated SMCs that failed to invest within and stabilize the fibrous cap. Exploratory mechanistic studies identified alterations in potential downstream regulatory genes, including large tumor suppressor kinase 2 (LATS2), which mediates macrophage marker and inflammatory cytokine expression on SMCs, and may explain how CHI3L1 modulates cellular plasticity.CHI3L1 is upregulated in humans with carotid artery disease and appears to be a strong mediator of plaque vulnerability. Mechanistic studies suggest this change may be a context-dependent adaptive response meant to maintain vascular SMCs in a differentiated state and to prevent rupture of the fibrous cap. Part of this effect may be mediated through downstream suppression of LATS2. Future studies should determine how these changes occur at the molecular level, and whether this gene can be targeted as a novel translational therapy for subjects at risk of stroke.Taken together, CHI3L1 has the potential to become a new translational target for cardiovascular disease. With further studies to understand its full causal relationship to inflammatory pathways, it could have a role in the diagnosis and management of patients with cerebrovascular disease at risk for stroke.

    View details for DOI 10.1093/cvr/cvab014

    View details for PubMedID 33471078

  • Reduction in Acute Limb Ischemia with Rivaroxaban versus Placebo in Peripheral Artery Disease after Lower Extremity Revascularization: Insights from VOYAGER PAD. Circulation Hess, C. N., Debus, E. S., Nehler, M. R., Anand, S. S., Patel, M. R., Szarek, M., Capell, W. H., Hsia, J., Beckman, J. A., Brodmann, M., Diaz, R., Habertheuer, P., Leeper, N. J., Powell, R. J., Sillesen, H., Muehlhofer, E., Berkowitz, S. D., Haskell, L. P., Bauersachs, R. M., Bonaca, M. P. 2021

    Abstract

    Background: Patients with peripheral artery disease (PAD) are at heightened risk of acute limb ischemia (ALI), a thrombotic event associated with amputation, disability, and mortality. Prior lower extremity revascularization (LER) is associated with increased ALI risk in chronic PAD. However, the pattern of risk, clinical correlates, and outcomes after ALI early after LER are not well-studied, and effective therapies to reduce ALI post-LER are lacking. Methods: VOYAGER PAD (NCT02504216) randomized patients with PAD undergoing LER to rivaroxaban 2.5 mg twice daily or placebo on a background of low-dose aspirin. The primary outcome was a composite of ALI, major amputation of vascular cause, myocardial infarction, ischemic stroke, or cardiovascular death. ALI was prospectively ascertained and adjudicated by a blinded committee. The cumulative incidence of ALI was calculated using Kaplan Meier estimates, and Cox proportional-hazards models were used to generate hazard ratios and associated confidence intervals. Analyses were performed as intention-to-treat. Results: Among 6,564 patients followed for a median of 2.3 years, 382 (5.8%) had a total of 508 ALI events. In placebo patients, the 3-year cumulative incidence of ALI was 7.8%. After multivariable modeling, prior LER, baseline ABI <0.50, surgical LER, and longer target lesion length were associated with increased risk of ALI. Incident ALI was associated with subsequent all-cause mortality (HR 2.59, 95% CI 1.98-3.39) and major amputation (HR 24.87, 95% CI 18.68-33.12). Rivaroxaban reduced ALI relative to placebo by 33% (absolute risk reduction 2.6% at 3 years, HR 0.67, 95% CI 0.55-0.82, P=0.0001), with benefit starting early (HR 0.45, 95% CI 0.24-0.85, P=0.0068 at 30 days). Benefit was present for severe ALI (associated with death, amputation, or prolonged hospitalization and ICU stay, HR 0.58, 95% CI 0.40-0.83, P=0.003) and regardless of LER type (surgical vs endovascular revascularization, p-interaction=0.42) or clopidogrel use (p-interaction=0.59). Conclusions: After LER for symptomatic PAD, ALI is frequent, particularly early after LER, and is associated with poor prognosis. Low-dose rivaroxaban plus aspirin reduces ALI after LER, including ALI events associated with the most severe outcomes. The benefit of rivaroxaban for ALI appears early, continues over time, and is consistent regardless of revascularization approach or clopidogrel use.

    View details for DOI 10.1161/CIRCULATIONAHA.121.055146

    View details for PubMedID 34637332

  • Intradialytic Hypotension and Newly Recognized Peripheral Artery Disease in Patients Receiving Hemodialysis. American journal of kidney diseases : the official journal of the National Kidney Foundation Seong, E. Y., Liu, S., Song, S. H., Leeper, N. J., Winkelmayer, W. C., Montez-Rath, M. E., Chang, T. I. 2020

    Abstract

    RATIONALE & OBJECTIVE: Intradialytic hypotension (IDH) may decrease systemic circulation to the legs, exacerbating symptoms of peripheral artery disease (PAD). We sought to evaluate the relationship between IDH and newly recognized lower extremity PAD among hemodialysis patients STUDY DESIGN: Retrospective cohort study.SETTING & PARTICIPANTS: Linking the data from USRDS to the electronic health records of a large dialysis provider, we identified adults patients (≥18 years) with Medicare Parts A and B who initiated dialysis (2006-2011) without previously recognized PAD.EXPOSURE: Time-varying proportion of hemodialysis sessions with IDH defined as nadir intradialytic systolic blood pressure <90 mmHg. We categorized the proportion of sessions with IDH within serial 30-day intervals as 0%, >0-<15%, 15-<30%, and ≥30%.OUTCOME: Newly recognized PAD, ascertained using PAD diagnosis codes and procedure codes for amputation or revascularization, in serial 30-day intervals subsequent to each 30-day exposure interval.ANALYTIC APPROACH: To account for the competing risks of death and kidney transplantation, we estimated unadjusted and adjusted sub-distribution hazard ratios using the Kaplan-Meier multiple imputation method in combination with the extended Cox model to account for IDH as a time-varying exposure.RESULTS: Among 45,591 patients, those with more frequent baseline IDH had a higher prevalence of cardiovascular diseases. During 61,725 person-years of follow-up, 7,886 patients had newly recognized PAD. We found a graded, direct association of IDH with newly recognized PAD. For example, having IDH in ≥30% of dialysis sessions during a given 30-day interval (versus 0%) was associated with a 24% higher hazard of having newly recognized PAD (95% CI, 17% to 32%) in the subsequent 30 days.LIMITATIONS: Unmeasured confounding; ascertainment of PAD from claims CONCLUSIONS: Patients receiving hemodialysis who had more frequent IDH had higher rates of newly recognized PAD. Patients with frequent IDH may warrant careful examination for PAD.

    View details for DOI 10.1053/j.ajkd.2020.10.012

    View details for PubMedID 33316351

  • Macrophage-targeted single walled carbon nanotubes stimulate phagocytosis via pH-dependent drug release NANO RESEARCH Zhang, Y., Ye, J., Hosseini-Nassab, N., Flores, A., Kalashnikova, I., Paluri, S., Lotfi, M., Leeper, N. J., Smith, B. 2020
  • Incentivizing physical activity through activity monitoring interventions in PAD - a pilot study. VASA. Zeitschrift fur Gefasskrankheiten Fukaya, E., Welden, S., Bukari, A., Khan, Z., Leeper, N., Mohler, E. 2020: 1–6

    Abstract

    Background: There is ample evidence to show that supervised exercise is efficacious and cost effective for improving claudication symptoms in patients with peripheral artery disease (PAD). Home based exercise therapy can be an effective alternative to supervised exercise however, the results of this is variable depending on the level of motivation and engagement of the patient. Patients and methods: We performed a pilot study in 41 patients to determine whether a home based exercise program with the use of an activity tracking device with personalized feedback and financial incentives can increase daily activity, improve walking and sustain engagement in the exercise regimen in patients with PAD. In this randomized pilot study, the patients in the study group were fitted with an activity monitoring device and given behavioral monitoring, motivational updates and feedback regarding their exercise program. This study group was further divided in to two groups. One half of these patients in the study group were also given financial incentives if they reached their set targets. The control group wore the device with no feedback or ability to see their number of steps walked. Results: Results showed that at the end of the 12 week period, patients in the study groups walked more compared to the controls and the financial incentive structure resulted in an additional 38-63% increase in average daily steps. Conclusions: This pilot study revealed that a home-based exercise program with activity monitoring, feedback and financial incentives resulted increased daily steps, 6-minute walking distance and overall compliance with the program in PAD patients with claudication.

    View details for DOI 10.1024/0301-1526/a000924

    View details for PubMedID 33150850

  • 18F-Fluorodeoxyglucose-Positron Emission Tomography Imaging Detects Response to Therapeutic Intervention and Plaque Vulnerability in a Murine Model of Advanced Atherosclerotic Disease. Arteriosclerosis, thrombosis, and vascular biology Jarr, K., Ye, J., Kojima, Y., Nanda, V., Flores, A. M., Tsantilas, P., Wang, Y., Hosseini-Nassab, N., Eberhard, A. V., Lotfi, M., Kaller, M., Smith, B. R., Maegdefessel, L., Leeper, N. J. 2020: ATVBAHA120315239

    Abstract

    OBJECTIVE: This study sought to determine whether 18F-fluorodeoxyglucose-positron emission tomography/computed tomography could be applied to a murine model of advanced atherosclerotic plaque vulnerability to detect response to therapeutic intervention and changes in lesion stability. Approach and Results: To analyze plaques susceptible to rupture, we fed ApoE-/- mice a high-fat diet and induced vulnerable lesions by cast placement over the carotid artery. After 9 weeks of treatment with orthogonal therapeutic agents (including lipid-lowering and proefferocytic therapies), we assessed vascular inflammation and several features of plaque vulnerability by 18F-fluorodeoxyglucose-positron emission tomography/computed tomography and histopathology, respectively. We observed that 18F-fluorodeoxyglucose-positron emission tomography/computed tomography had the capacity to resolve histopathologically proven changes in plaque stability after treatment. Moreover, mean target-to-background ratios correlated with multiple characteristics of lesion instability, including the corrected vulnerability index.CONCLUSIONS: These results suggest that the application of noninvasive 18F-fluorodeoxyglucose-positron emission tomography/computed tomography to a murine model can allow for the identification of vulnerable atherosclerotic plaques and their response to therapeutic intervention. This approach may prove useful as a drug discovery and prioritization method.

    View details for DOI 10.1161/ATVBAHA.120.315239

    View details for PubMedID 33086865

  • Toward Automated Detection of Peripheral Artery Disease Using Electronic Health Records Vy Thuy Ho, Leeper, N., Shah, N., Ross, E. MOSBY-ELSEVIER. 2020: E41
  • Identifying dietary and nutritional risk factors for symptomatic peripheral arterial disease using the UK biobank cohort study Kaufman, A., Fukaya, E., Leeper, N., Ross, E. SAGE PUBLICATIONS LTD. 2020: NP5
  • The impact of low-dose anticoagulation therapy on peripheral artery disease: insights from the VOYAGER trial. Cardiovascular research Fukaya, E. n., Leeper, N. J. 2020; 116 (12): e156–e158

    View details for DOI 10.1093/cvr/cvaa225

    View details for PubMedID 32980875

  • Real-World Predictors of Major Adverse Cardiovascular Events and Major Adverse Limb Events Among Patients with Chronic Coronary Artery Disease and/or Peripheral Arterial Disease. Advances in therapy Berger, A., Simpson, A., Leeper, N., Murphy, B., Nordstrom, B., Ting, W., Zhao, Q., Berger, J. 2019

    Abstract

    INTRODUCTION: Collectively, coronary artery disease (CAD) and peripheral artery disease (PAD) are highly prevalent and are associated with increased risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Improved ability to identify those at highest risk of these events may help optimize secondary prevention efforts in this population.METHODS: Using the Optum Integrated Database, a healthcare claims database linked to electronic medical records (EMR), we identified patients with CAD and/or PAD between January 1, 2009, and September 30, 2016. Index date was the earliest date on which chronic and stable disease was established. Follow-up ran from index date until earliest of patient death, plan disenrollment, or end of study. We developed multivariate Cox proportional hazards models to identify predictors of MACE and/or MALE, limited to measures presumed available to clinicians during patient encounters (e.g., age, presence of selected comorbidities).RESULTS: A total of 20,932 patients met all selection criteria; 86.9% had CAD and 26.1% had PAD; 13% (n=2753) experienced MACE and/or MALE during a mean follow-up of 2.3years, for a rate of 7.1 events per 100 person-years (PYs). We identified 11 predictors of MACE and/or MALE. Most (95.1%) patients had≥1 predictors; 34.0% and 6.9% had≥4 and≥6, respectively. Incidence of MACE and/or MALE was strongly correlated with number of predictors (r2=0.98), ranging from 2.3 per 100 PYs among those without predictors (4.9% of patients) to 18.7 per 100 PYs among those with≥6 (6.9%). Patients with≥1 predictor experienced 7.4 MACE and/or MALE per 100 PYs.CONCLUSION: Readily identifiable predictors can be used to identify subgroups with chronic CAD and/or PAD at elevated risk of MACE and/or MALE. Further research is required to understand the degree to which these subgroups may benefit from early identification and treatment with secondary prevention therapies.FUNDING: Janssen Pharmaceuticals.

    View details for DOI 10.1007/s12325-019-01132-z

    View details for PubMedID 31705434

  • Resolvin D1 promotes the targeting and clearance of necroptotic cells. Cell death and differentiation Gerlach, B. D., Marinello, M., Heinz, J., Rymut, N., Sansbury, B. E., Riley, C. O., Sadhu, S., Hosseini, Z., Kojima, Y., Tang, D. D., Leeper, N. J., Spite, M., Barroso, M., Rayner, K. J., Fredman, G. 2019

    Abstract

    Inflammation-resolution is a protective response that is mediated by specialized pro-resolving mediators (SPMs). The clearance of dead cells or efferocytosis is a critical cellular program of inflammation-resolution. Impaired efferocytosis can lead to tissue damage in prevalent human diseases, like atherosclerosis. Therefore understanding mechanisms associated with swift clearance of dead cells is of utmost clinical importance. Recently, the accumulation of necroptotic cells (NCs) was observed in human plaques and we postulated that this is due to defective clearance programs. Here we present evidence that NCs are inefficiently taken up by macrophages because they have increased surface expression of a well-known "don't eat me" signal called CD47. High levels of CD47 on NCs stimulated RhoA-pMLC signaling in macrophages that promoted "nibbling", rather than whole-cell engulfment of NCs. Anti-CD47 blocking antibodies limited RhoA-p-MLC signaling and promoted whole-cell NC engulfment. Treatment with anti-CD47 blocking antibodies to Ldlr-/- mice with established atherosclerosis decreased necrotic cores, limited the accumulation of plaque NCs and increased lesional SPMs, including Resolvin D1 (RvD1) compared with IgG controls. Mechanistically, RvD1 promoted whole-cell engulfment of NCs by decreasing RhoA signaling and activating CDC42. RvD1 specifically targeted NCs for engulfment by facilitating the release of the well-known "eat me signal" called calreticulin from macrophages in a CDC42 dependent manner. Lastly, RvD1 enhanced the clearance of NCs in advanced murine plaques. Together, these results suggest new molecules and signaling associated with the clearance of NCs, provide a new paradigm for the regulation of inflammation-resolution, and offer a potential treatment strategy for diseases where NCs underpin the pathology.

    View details for DOI 10.1038/s41418-019-0370-1

    View details for PubMedID 31222041

  • Incidence and Cost of Major Adverse Cardiovascular Events and Major Adverse Limb Events in Patients With Chronic Coronary Artery Disease or Peripheral Artery Disease AMERICAN JOURNAL OF CARDIOLOGY Berger, A., Simpson, A., Bhagnani, T., Leeper, N. J., Murphy, B., Nordstrom, B., Ting, W., Zhao, Q., Berger, J. S. 2019; 123 (12): 1893–99
  • A Comprehensive Evaluation of Lifestyle and Social Factors Related to Peripheral Artery Disease Events in a Large Longitudinal Study Ross, E., Leeper, N., Ingelsson, E. MOSBY-ELSEVIER. 2019: E54–E55
  • Clonal Smooth Muscle Cell Expansion, Autophagy, and Vascular Integrity in Aortic Aneurysm Disease. Arteriosclerosis, thrombosis, and vascular biology Wang, Y., Nanda, V., Leeper, N. J. 2019; 39 (6): 982–83

    View details for DOI 10.1161/ATVBAHA.119.312739

    View details for PubMedID 31116606

  • Smooth Muscle Cells Contribute the Majority of Foam Cells in ApoE (Apolipoprotein E)-Deficient Mouse Atherosclerosis. Arteriosclerosis, thrombosis, and vascular biology Wang, Y., Dubland, J. A., Allahverdian, S., Asonye, E., Sahin, B., Jaw, J. E., Sin, D. D., Seidman, M. A., Leeper, N. J., Francis, G. A. 2019; 39 (5): 876-887

    Abstract

    Objective- Smooth muscle cells (SMCs) are the most abundant cells in human atherosclerotic lesions and are suggested to contribute at least 50% of atheroma foam cells. In mice, SMCs contribute fewer total lesional cells. The purpose of this study was to determine the contribution of SMCs to total foam cells in apolipoprotein E-deficient (ApoE-/-) mice, and the utility of these mice to model human SMC foam cell biology and interventions. Approach and Results- Using flow cytometry, foam cells in the aortic arch of ApoE-/- mice were characterized based on the expression of leukocyte-specific markers. Nonleukocyte foam cells increased from 37% of total foam cells in 27-week-old to 75% in 57-week-old male ApoE-/- mice fed a chow diet and were ≈70% in male and female ApoE-/- mice following 6 weeks of Western diet feeding. A similar contribution to total foam cells by SMCs was found using SMC-lineage tracing ApoE-/- mice fed the Western diet for 6 or 12 weeks. Nonleukocyte foam cells contributed a similar percentage of total atheroma cholesterol and exhibited lower expression of the cholesterol exporter ABCA1 (ATP-binding cassette transporter A1) when compared with leukocyte-derived foam cells. Conclusions- Consistent with previous studies of human atheromas, we present evidence that SMCs contribute the majority of atheroma foam cells in ApoE-/- mice fed a Western diet and a chow diet for longer periods. Reduced expression of ABCA1, also seen in human intimal SMCs, suggests a common mechanism for formation of SMC foam cells across species, and represents a novel target to enhance atherosclerosis regression.

    View details for DOI 10.1161/ATVBAHA.119.312434

    View details for PubMedID 30786740

  • Nanoparticle Therapy for Vascular Diseases ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Flores, A. M., Ye, J., Jarr, K., Hosseini-Nassab, N., Smith, B. R., Leeper, N. J. 2019; 39 (4): 635–46
  • Predicting Future Cardiovascular Events in Patients With Peripheral Artery Disease Using Electronic Health Record Data CIRCULATION-CARDIOVASCULAR QUALITY AND OUTCOMES Ross, E., Jung, K., Dudley, J. T., Li, L., Leeper, N. J., Shah, N. H. 2019; 12 (3)
  • Predicting Future Cardiovascular Events in Patients With Peripheral Artery Disease Using Electronic Health Record Data. Circulation. Cardiovascular quality and outcomes Ross, E. G., Jung, K., Dudley, J. T., Li, L., Leeper, N. J., Shah, N. H. 2019; 12 (3): e004741

    Abstract

    BACKGROUND: Patients with peripheral artery disease (PAD) are at risk of major adverse cardiac and cerebrovascular events. There are no readily available risk scores that can accurately identify which patients are most likely to sustain an event, making it difficult to identify those who might benefit from more aggressive intervention. Thus, we aimed to develop a novel predictive model-using machine learning methods on electronic health record data-to identify which PAD patients are most likely to develop major adverse cardiac and cerebrovascular events.METHODS AND RESULTS: Data were derived from patients diagnosed with PAD at 2 tertiary care institutions. Predictive models were built using a common data model that allowed for utilization of both structured (coded) and unstructured (text) data. Only data from time of entry into the health system up to PAD diagnosis were used for modeling. Models were developed and tested using nested cross-validation. A total of 7686 patients were included in learning our predictive models. Utilizing almost 1000 variables, our best predictive model accurately determined which PAD patients would go on to develop major adverse cardiac and cerebrovascular events with an area under the curve of 0.81 (95% CI, 0.80-0.83).CONCLUSIONS: Machine learning algorithms applied to data in the electronic health record can learn models that accurately identify PAD patients at risk of future major adverse cardiac and cerebrovascular events, highlighting the great potential of electronic health records to provide automated risk stratification for cardiovascular diseases. Common data models that can enable cross-institution research and technology development could potentially be an important aspect of widespread adoption of newer risk-stratification models.

    View details for PubMedID 30857412

  • Nanoparticle Therapy for Vascular Diseases. Arteriosclerosis, thrombosis, and vascular biology Flores, A. M., Ye, J., Jarr, K., Hosseini-Nassab, N., Smith, B. R., Leeper, N. J. 2019: ATVBAHA118311569

    Abstract

    Nanoparticles promise to advance strategies to treat vascular disease. Since being harnessed by the cancer field to deliver safer and more effective chemotherapeutics, nanoparticles have been translated into applications for cardiovascular disease. Systemic exposure and drug-drug interactions remain a concern for nearly all cardiovascular therapies, including statins, antithrombotic, and thrombolytic agents. Moreover, off-target effects and poor bioavailability have limited the development of completely new approaches to treat vascular disease. Through the rational design of nanoparticles, nano-based delivery systems enable more efficient delivery of a drug to its therapeutic target or even directly to the diseased site, overcoming biological barriers and enhancing a drug's therapeutic index. In addition, advances in molecular imaging have led to the development of theranostic nanoparticles that may simultaneously act as carriers of both therapeutic and imaging payloads. The following is a summary of nanoparticle therapy for atherosclerosis, thrombosis, and restenosis and an overview of recent major advances in the targeted treatment of vascular disease.

    View details for PubMedID 30786744

  • Incidence and Cost of Major Adverse Cardiovascular Events and Major Adverse Limb Events in Patients With Chronic Coronary Artery Disease or Peripheral Artery Disease. The American journal of cardiology Berger, A. n., Simpson, A. n., Bhagnani, T. n., Leeper, N. J., Murphy, B. n., Nordstrom, B. n., Ting, W. n., Zhao, Q. n., Berger, J. S. 2019

    Abstract

    Chronic coronary artery disease (CAD) and peripheral artery disease (PAD) are both associated with elevated risks of major adverse cardiovascular events (MACE) and major adverse limb events (MALE). The frequency of these events in patients with CAD or PAD, and their corresponding costs, are not well understood. Accordingly, we describe the incidence and cost of both MACE and MALE in patients with CAD or PAD. Using a database that included healthcare claims linked to electronic medical records, we identified patients with evidence of chronic CAD and PAD, respectively, between January 1, 2009, and September 30, 2016. We assessed the occurrence of MACE (defined as myocardial infarction, stroke, or cardiovascular-related death) and MALE (critical limb ischemia, amputation, or peripheral artery disease-related revascularization). A total of 99,730 patients met all selection criteria: 86.0% had CAD, 25.8% had PAD, and 11.8% had both. Mean (±standard deviation) age was 67.7 (±11.5) years and 59.8% were male. During follow-up (mean: 1.8 years), 13.6% experienced MACE or MALE (6.3 per 100 person-years [PYs]), predominantly MACE (9.6% [4.3 per 100 PYs]). Adjusted 1-year healthcare costs were $44,495 greater in patients who experienced MACE or MALE (mean [95% confidence interval]: $64,099 [$33,254 to $123,557] vs $19,604 [$10,175 to $37,771]; p < 0.001). In conclusion, approximately 1 in 7 patients with chronic CAD or PAD experiences additional MACE or MALE within approximately 2 years of follow-up; the relatively high risk and cost of these events highlight the need for new secondary prevention therapies that may improve outcomes in these patients.

    View details for PubMedID 31014542

  • Smooth muscle cells contribute the majority of foam cells in apolipoprotein E-deficient mouse atherosclerosis Arteriosclerosis, Thrombosis, and Vascular Biology (In press) Wang, Y., Dubland, J., Allahverdian, S., Asonye, E., Sahin, B., Jaw, J., Sin, D., Seidman, M., Leeper, N., Francis, G. 2019 : 876–87

    Abstract

    Objective- Smooth muscle cells (SMCs) are the most abundant cells in human atherosclerotic lesions and are suggested to contribute at least 50% of atheroma foam cells. In mice, SMCs contribute fewer total lesional cells. The purpose of this study was to determine the contribution of SMCs to total foam cells in apolipoprotein E-deficient (ApoE-/-) mice, and the utility of these mice to model human SMC foam cell biology and interventions. Approach and Results- Using flow cytometry, foam cells in the aortic arch of ApoE-/- mice were characterized based on the expression of leukocyte-specific markers. Nonleukocyte foam cells increased from 37% of total foam cells in 27-week-old to 75% in 57-week-old male ApoE-/- mice fed a chow diet and were ≈70% in male and female ApoE-/- mice following 6 weeks of Western diet feeding. A similar contribution to total foam cells by SMCs was found using SMC-lineage tracing ApoE-/- mice fed the Western diet for 6 or 12 weeks. Nonleukocyte foam cells contributed a similar percentage of total atheroma cholesterol and exhibited lower expression of the cholesterol exporter ABCA1 (ATP-binding cassette transporter A1) when compared with leukocyte-derived foam cells. Conclusions- Consistent with previous studies of human atheromas, we present evidence that SMCs contribute the majority of atheroma foam cells in ApoE-/- mice fed a Western diet and a chow diet for longer periods. Reduced expression of ABCA1, also seen in human intimal SMCs, suggests a common mechanism for formation of SMC foam cells across species, and represents a novel target to enhance atherosclerosis regression.

    View details for DOI 10.1161/ATVBAHA.119.312434

  • Clinical and Genetic Determinants of Varicose Veins. Circulation Fukaya, E., Flores, A. M., Lindholm, D., Gustafsson, S., Zanetti, D., Ingelsson, E., Leeper, N. J. 2018; 138 (25): 2869–80

    Abstract

    BACKGROUND: Varicose veins are a common problem with no approved medical therapies. Although it is believed that varicose vein pathogenesis is multifactorial, there is limited understanding of the genetic and environmental factors that contribute to their formation. Large-scale studies of risk factors for varicose veins may highlight important aspects of pathophysiology and identify groups at increased risk for disease.METHODS: We applied machine learning to agnostically search for risk factors of varicose veins in 493519 individuals in the UK Biobank. Predictors were further studied with univariable and multivariable Cox regression analyses (2441 incident events). A genome-wide association study of varicose veins was also performed among 337536 unrelated individuals (9577 cases) of white British descent, followed by expression quantitative loci and pathway analyses. Because height emerged as a new candidate risk factor, we performed mendelian randomization analyses to assess a potential causal role for height in varicose vein development.RESULTS: Machine learning confirmed several known (age, sex, obesity, pregnancy, history of deep vein thrombosis) and identified several new risk factors for varicose vein disease, including height. After adjustment for traditional risk factors in Cox regression, greater height remained independently associated with varicose veins (hazard ratio for upper versus lower quartile, 1.74; 95% CI, 1.51-2.01; P<0.0001). A genome-wide association study identified 30 new genome-wide significant loci, identifying pathways involved in vascular development and skeletal/limb biology. Mendelian randomization analysis provided evidence that increased height is causally related to varicose veins (inverse-variance weighted: odds ratio, 1.26; P=2.07*10-16).CONCLUSIONS: Using data from nearly a half-million individuals, we present a comprehensive genetic and epidemiological study of varicose veins. We identified novel clinical and genetic risk factors that provide pathophysiological insights and could help future improvements of treatment of varicose vein disease.

    View details for PubMedID 30566020

  • Functional regulatory mechanism of smooth muscle cell-restricted LMOD1 coronary artery disease locus PLOS GENETICS Nanda, V., Wang, T., Pjanic, M., Liu, B., Trieu Nguyen, Matic, L., Hedin, U., Koplev, S., Ma, L., Franzen, O., Ruusalepp, A., Schadt, E. E., Bjorkegren, J. M., Montgomery, S. B., Snyder, M. P., Quertermous, T., Leeper, N. J., Miller, C. L. 2018; 14 (11)
  • Association of Blood Pressure Measurements With Peripheral Artery Disease Events: Reanalysis of the ALLHAT Data CIRCULATION Itoga, N. K., Tawfik, D. S., Lee, C. K., Maruyama, S., Leeper, N. J., Chang, T. I. 2018; 138 (17): 1805–14
  • Loss of CDKN2B Promotes Fibrosis via Increased Fibroblast Differentiation Rather Than Proliferation AMERICAN JOURNAL OF RESPIRATORY CELL AND MOLECULAR BIOLOGY Scruggs, A. M., Koh, H. B., Tripathi, P., Leeper, N. J., White, E. S., Huang, S. K. 2018; 59 (2): 200–214

    Abstract

    Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease characterized by excessive scarring and fibroblast activation. We previously showed that fibroblasts from patients with IPF are hypermethylated at the CDKN2B gene locus, resulting in decreased CDKN2B expression. Here, we examine how diminished CDKN2B expression in normal and IPF fibroblasts affect fibroblast function, and how loss of CDKN2B contributes to IPF pathogenesis. We first confirmed that protein expression of CDKN2B was diminished in IPF lungs in situ. Loss of CDKN2B was especially notable in regions of increased myofibroblasts and fibroblastic foci. The degree of CDKN2B hypermethylation was particularly elevated in patients with radiographic honeycombing, a marker of more advanced fibrosis, and increased DNA methylation correlated with decreased expression. Although CDKN2B is traditionally considered a cell cycle inhibitor, loss of CDKN2B did not result in an increase in fibroblast proliferation, but instead was associated with an increase in myofibroblast differentiation. An increase in myofibroblast differentiation was not observed when CDKN2A was silenced. Loss of CDKN2B was associated with an increase in the transcription factors serum response factor and myocardin-related transcription factor A, and overexpression of CDKN2B in IPF fibroblasts inhibited myofibroblast differentiation. Finally, decreased CDKN2B expression was noted in fibroblasts from a murine model of fibrosis, and Cdkn2b-/- mice developed greater histologic fibrosis after bleomycin injury. These findings identify a novel function for CDKN2B that differs from its conventional designation as a cell cycle inhibitor and demonstrate the importance of this protein in pulmonary fibrosis.

    View details for PubMedID 29420051

  • Trends in Rates of Lower Extremity Amputation Among Patients With End-stage Renal Disease Who Receive Dialysis. JAMA internal medicine Franz, D., Zheng, Y., Leeper, N. J., Chandra, V., Montez-Rath, M., Chang, T. I. 2018

    Abstract

    Patients with end-stage renal disease (ESRD) who receive dialysis are at high risk of lower extremity amputation. Recent studies indicate decreasing rates of lower extremity amputation in non-ESRD populations, but contemporary data for patients with ESRD who receive dialysis are lacking.To assess rates of lower extremity amputation among patients with ESRD who receive dialysis during a recent 15-year period; to analyze whether those rates differed by age, sex, diabetes, or geographic region; and to determine 1-year mortality rates in this population after lower extremity amputation.This retrospective study of 3 700 902 records obtained from a US national registry of patients with ESRD who receive dialysis assessed cross-sectional cohorts for each calendar year from 2000 through 2014. Adult patients with prevalent ESRD treated with hemodialysis or peritoneal dialysis covered by Medicare Part A and B on January 1 of each cohort year were included. Data analysis was conducted from August 2017 to April 2018.Age, sex, diabetes, and hospital referral region.Annual rates per 100 person-years of nontraumatic major (above- or below-knee) and minor (below-ankle) amputations.For each annual cohort, there were fewer women (47.5% in 2000, 46.2% in 2005, 44.9% in 2010, and 44.0% in 2014) than men, more than half the patients were white individuals (58.1% in 2000, 56.9% in 2005, 56.9% in 2010, and 56.7% in 2014), and a small proportion were employed (13.9% in 2000, 15.1% in 2005, 16.1% in 2010, and 16.5% in 2014). The rate of lower extremity amputations for patients with ESRD who receive dialysis decreased by 51.0% from 2000 to 2014, driven primarily by a decrease in the rate of major amputations (5.42 [95% CI, 5.28-5.56] in 2000 vs 2.66 [95% CI, 2.59-2.72] per 100 person-years in 2014). Patients with diabetes had amputation rates more than 5 times as high as patients without diabetes. Patients younger than 65 years had higher adjusted amputation rates than older patients, and men had consistently higher adjusted amputation rates than women. Adjusted 1-year mortality rates after lower extremity amputation for patients with ESRD who receive dialysis decreased from 52.2% (95% CI, 50.9%-53.4%) in 2000 to 43.6% (95% CI, 42.5%-44.8%) in 2013. In general, amputation rates decreased among all regions from 2000 to 2014, but regional variability persisted across time despite adjustment for differences in patient demographics and comorbid conditions.Although rates of lower extremity amputations among US patients with ESRD who receive dialysis decreased by 51% during a recent 15-year period, mortality rates remained high, with nearly half of patients dying within a year after lower extremity amputation. Our results highlight the need for more research on ways to prevent lower extremity amputation in this extremely high-risk population.

    View details for DOI 10.1001/jamainternmed.2018.2436

    View details for PubMedID 29987332

  • Bioimpedance and New-Onset Heart Failure: A Longitudinal Study of >500 000 Individuals From the General Population JOURNAL OF THE AMERICAN HEART ASSOCIATION Lindholm, D., Fukaya, E., Leeper, N. J., Ingelsson, E. 2018; 7 (13)

    Abstract

    Heart failure constitutes a high burden on patients and society, but although lifetime risk is high, it is difficult to predict without costly or invasive testing. We aimed to establish new risk factors of heart failure, which potentially could enable early diagnosis and preemptive treatment.We applied machine learning in the UK Biobank in an agnostic search of risk factors for heart failure in 500 451 individuals, excluding individuals with prior heart failure. Novel factors were then subjected to several in-depth analyses, including multivariable Cox models of incident heart failure, and assessment of discrimination and calibration. Machine learning confirmed many known and putative risk factors for heart failure and identified several novel candidates. Mean reticulocyte volume appeared as one novel factor and leg bioimpedance another, the latter appearing as the most important new marker. Leg bioimpedance was lower in those who developed heart failure during an up to 9.8-year follow-up. When adjusting for known heart failure risk factors, leg bioimpedance was inversely related to heart failure (hazard ratio [95% confidence interval], 0.60 [0.48-0.73] and 0.75 [0.59-0.94], in age- and sex-adjusted and fully adjusted models, respectively, comparing the upper versus lower quartile). A model including leg bioimpedance, age, sex, and self-reported history of myocardial infarction showed good discrimination for future heart failure hospitalization (Concordance index [C-index]=0.82) and good calibration.Leg bioimpedance is inversely associated with heart failure incidence in the general population. A simple model of exclusively noninvasive measures, combining leg bioimpedance with history of myocardial infarction, age, and sex provides accurate predictive capacity.

    View details for PubMedID 29959136

  • Association of Blood Pressure Measurements with Peripheral Arterial Disease Events: A Reanalysis of the ALLHAT Data. Circulation Itoga, N. K., Tawfik, D. S., Lee, C. K., Maruyama, S., Leeper, N. J., Chang, T. I. 2018

    Abstract

    Background -Current guidelines recommend treating hypertension in patients with peripheral arterial disease (PAD) to reduce the risk of cardiac events and stroke, but the effect of reducing blood pressure on lower extremity PAD events is largely unknown. We investigated the association of blood pressure with lower extremity PAD events using data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). Methods -ALLHAT investigated the effect of different antihypertensive medication classes (chlorthalidone, amlodipine, lisinopril, or doxazosin) on cardiovascular events. Using these data, the primary outcome in our analysis was time to first lower extremity PAD event, defined as PAD-related hospitalization, procedures, medical treatment, or PAD-related death. Given the availability of longitudinal standardized blood pressure measurements, we analyzed systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (PP) as time-varying categorical variables (reference categories 120-129 mm Hg for SBP, 70-79 mm Hg for DBP, and 45-54 mm Hg for PP) in separate models. We used extended Cox regression with death as a competing risk to calculate the association of each BP component with PAD events, and report the results as sub-distribution hazard ratios (HR) and 95% confidence intervals (CI). Results -The present analysis included 33,357 patients with an average age of 67.4 years, 53.1% men, 59.7% white race, and 36.2% with diabetes mellitus. The median baseline blood pressure was 146/84 mm Hg. Participants were followed for a median of 4.3 (IQR 3.6-5.3) years, during which time 1,489 (4.5%) had a lower extremity PAD event, and 4,148 (12.4%) died. In models adjusted for demographic and clinical characteristics, SBP <120 mm Hg was associated with a 26% (CI 5-52%, P=0.015) higher hazard and SBP≥160 mm Hg was associated with a 21% (CI 0-48%, P=0.050) higher hazard for a PAD event, compared with SBP 120-129 mm Hg. In contrast, lower, but not higher, DBP was associated with higher hazard of PAD events: for DBP <60 mm Hg HR = 1.72 (CI 1.38 - 2.16). PP had a U-shaped association with PAD events. Conclusions -In this re-analysis of data from ALLHAT, we found a higher rate of lower extremity PAD events with higher and lower SBP and PP, and with lower DBP. Given the recent revised blood pressure guidelines advocating lower SBP targets for overall cardiovascular risk reduction, further refinement of optimal blood pressure targets specific to PAD is needed. Clinical Trial Registration -URL: www.clinicaltrials.gov Unique identifier: NCT00000542.

    View details for PubMedID 29930023

  • Clinical and genetic determinants of varicose veins: a prospective, community-based prospective study of similar to 500,000 individuals Fukaya, E., Flores, A., Lindholm, D., Gustafsson, S., Ingelsson, E., Leeper, N. SAGE PUBLICATIONS LTD. 2018: 300
  • Thrombotic Regulation From the Endothelial Cell Perspectives ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Wang, M., Hao, H., Leeper, N. J., Zhu, L., Early Career Comm 2018; 38 (6): E90–E95

    View details for PubMedID 29793992

  • Non-coding RNAs: key regulators of smooth muscle cell fate in vascular disease CARDIOVASCULAR RESEARCH Leeper, N. J., Maegdefessel, L. 2018; 114 (4): 611–21

    Abstract

    The vascular smooth muscle cell (SMC) is one of the most plastic cells in the body. Understanding how non-coding RNAs (ncRNAs) regulate SMC cell-fate decision making in the vasculature has significantly enhanced our understanding of disease development, and opened up exciting new avenues for potential therapeutic applications. Recent studies on SMC physiology have in addition challenged our traditional view on their role and contribution to vascular disease, mainly in the setting of atherosclerosis as well as aneurysm disease, and restenosis after angioplasties. The impact of SMC behaviour on vascular disease is now recognized to be context dependent; SMC proliferation and migration can be harmful or beneficial, whereas their apoptosis, senescence, and switching into a more macrophage-like phenotype can promote inflammation and disease progression. This is in particular true for atherosclerosis-related diseases, where proliferation of SMCs was believed to promote lesion formation, but may also prevent plaque rupture by stabilizing the fibrous cap. Based on newer findings of genetic lineage tracing studies, it was revealed that SMC phenotypic switching can result in less-differentiated forms that lack classical SMC markers while exhibiting functions more related to macrophage-like cells. This switching can directly promote atherogenesis. The aim of this current review is to summarize and discuss how ncRNAs (mainly microRNAs and long ncRNAs) are involved in SMC plasticity, and how they directly affect vascular disease development and progression. Finally, we want to critically assess where potential future therapies could be useful to influence the burden of vascular diseases.

    View details for PubMedID 29300828

    View details for PubMedCentralID PMC5852528

  • Consideration of Sex Differences in Design and Reporting of Experimental Arterial Pathology Studies-Statement From ATVB Council ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Robinet, P., Milewicz, D. M., Cassis, L. A., Leeper, N. J., Lu, H. S., Smith, J. D. 2018; 38 (2): 292–303

    Abstract

    There are many differences in arterial diseases between men and women, including prevalence, clinical manifestations, treatments, and prognosis. The new policy of the National Institutes of Health, which requires the inclusion of sex as a biological variable for preclinical studies, aims to foster new mechanistic insights and to enhance our understanding of sex differences in human diseases. The purpose of this statement is to suggest guidelines for designing and reporting sex as a biological variable in animal models of atherosclerosis, thoracic and abdominal aortic aneurysms, and peripheral arterial disease. We briefly review sex differences of these human diseases and their animal models, followed by suggestions on experimental design and reporting of animal studies for these vascular pathologies.

    View details for PubMedID 29301789

    View details for PubMedCentralID PMC5785439

  • Trends in Rates of Lower Extremity Amputation Among Patients With End-Stage Renal Disease Who Receive Dialysis JAMA Internal Medicine Franz, D., Zheng, Y., Leeper, N. J., Chandra, V., Montez-Rath, M., Chang, T. I. 2018
  • Functional regulatory mechanism of smooth muscle cell-restricted LMOD1 coronary artery disease locus. PLoS genetics Nanda, V. n., Wang, T. n., Pjanic, M. n., Liu, B. n., Nguyen, T. n., Matic, L. P., Hedin, U. n., Koplev, S. n., Ma, L. n., Franzén, O. n., Ruusalepp, A. n., Schadt, E. E., Björkegren, J. L., Montgomery, S. B., Snyder, M. P., Quertermous, T. n., Leeper, N. J., Miller, C. L. 2018; 14 (11): e1007755

    Abstract

    Recent genome-wide association studies (GWAS) have identified multiple new loci which appear to alter coronary artery disease (CAD) risk via arterial wall-specific mechanisms. One of the annotated genes encodes LMOD1 (Leiomodin 1), a member of the actin filament nucleator family that is highly enriched in smooth muscle-containing tissues such as the artery wall. However, it is still unknown whether LMOD1 is the causal gene at this locus and also how the associated variants alter LMOD1 expression/function and CAD risk. Using epigenomic profiling we recently identified a non-coding regulatory variant, rs34091558, which is in tight linkage disequilibrium (LD) with the lead CAD GWAS variant, rs2820315. Herein we demonstrate through expression quantitative trait loci (eQTL) and statistical fine-mapping in GTEx, STARNET, and human coronary artery smooth muscle cell (HCASMC) datasets, rs34091558 is the top regulatory variant for LMOD1 in vascular tissues. Position weight matrix (PWM) analyses identify the protective allele rs34091558-TA to form a conserved Forkhead box O3 (FOXO3) binding motif, which is disrupted by the risk allele rs34091558-A. FOXO3 chromatin immunoprecipitation and reporter assays show reduced FOXO3 binding and LMOD1 transcriptional activity by the risk allele, consistent with effects of FOXO3 downregulation on LMOD1. LMOD1 knockdown results in increased proliferation and migration and decreased cell contraction in HCASMC, and immunostaining in atherosclerotic lesions in the SMC lineage tracing reporter mouse support a key role for LMOD1 in maintaining the differentiated SMC phenotype. These results provide compelling functional evidence that genetic variation is associated with dysregulated LMOD1 expression/function in SMCs, together contributing to the heritable risk for CAD.

    View details for PubMedID 30444878

  • A Missing LNC in Vascular Diseases CIRCULATION RESEARCH Cooke, J. P., Leeper, N. J. 2017; 121 (4): 320–22

    View details for PubMedID 28775007

    View details for PubMedCentralID PMC5637485

  • MiRNA-210 Enhances Fibrous Cap Stability in Advanced Atherosclerotic Lesions Eken, S. M., Jin, H., Chernogubova, E., Li, Y., Simon, N., Sun, C., Korzunowicz, G., Busch, A., Backlund, A., Osterholm, C., Razuvaev, A., Renne, T., Eckstein, H. H., Pelisek, J., Eriksson, P., Diez, M., Perisic, L., Schellinger, I. N., Raaz, U., Leeper, N. J., Hansson, G. K., Paulsson-Berne, G., Hedin, U., Maegdefessel, L. LIPPINCOTT WILLIAMS & WILKINS. 2017
  • A CD47-associated super-enhancer links pro-inflammatory signalling to CD47 upregulation in breast cancer NATURE COMMUNICATIONS Betancur, P. A., Abraham, B. J., Yiu, Y. Y., Willingham, S. B., Khameneh, F., Zarnegar, M., Kuo, A. H., McKenna, K., Kojima, Y., Leeper, N. J., Ho, P., Gip, P., Swigut, T., Sherwood, R. I., Clarke, M. F., Somlo, G., Young, R. A., Weissman, I. L. 2017; 8

    Abstract

    CD47 is a cell surface molecule that inhibits phagocytosis of cells that express it by binding to its receptor, SIRPα, on macrophages and other immune cells. CD47 is expressed at different levels by neoplastic and normal cells. Here, to reveal mechanisms by which different neoplastic cells generate this dominant 'don't eat me' signal, we analyse the CD47 regulatory genomic landscape. We identify two distinct super-enhancers (SEs) associated with CD47 in certain cancer cell types. We show that a set of active constituent enhancers, located within the two CD47 SEs, regulate CD47 expression in different cancer cell types and that disruption of CD47 SEs reduces CD47 gene expression. Finally we report that the TNF-NFKB1 signalling pathway directly regulates CD47 by interacting with a constituent enhancer located within a CD47-associated SE specific to breast cancer. These results suggest that cancers can evolve SE to drive CD47 overexpression to escape immune surveillance.

    View details for DOI 10.1038/ncomms14802

    View details for Web of Science ID 000398343600001

    View details for PubMedID 28378740

  • The Intersection of Genome-Wide Association Studies and High-Throughput Small Interfering Ribonucleic Acid Screens Allows for the Identification of Novel Pathways Relevant to Atherosclerosis. JACC. Basic to translational science Nanda, V., Xiao, S., Ye, J., Leeper, N. J. 2017; 2 (2): 209–11

    Abstract

    It is now known that the internalization and transcytosis of low density lipoprotein (LDL) in the vessel wall occurs through molecular pathways independent of the LDL receptor. In a study recently published in Nature Communications, investigators cross-referenced results from a genome-wide ribonucleic acid interference screen with targets identified in publicly-available genome-wide association studies datasets to identify activin-like kinase 1 as a novel driver of this process. This approach has relevance to the field of atherosclerosis, and could be used as a model for the prioritization of future "hits" in large-scale genomic screens.

    View details for PubMedID 30167568

  • "Attack of the Clones": Commonalities Between Cancer and Atherosclerosis. Circulation research DiRenzo, D., Owens, G. K., Leeper, N. J. 2017; 120 (4): 624-626

    View details for DOI 10.1161/CIRCRESAHA.116.310091

    View details for PubMedID 28209794

  • Evaluation of Cell Therapy on Exercise Performance and Limb Perfusion in Peripheral Artery Disease: The CCTRN Patients with Intermittent Claudication Injected with ALDH Bright Cells (PACE) Trial. Circulation Perin, E. C., Murphy, M. P., March, K. L., Bolli, R., Loughran, J., Yang, P. C., Leeper, N. J., Dalman, R. L., Alexander, J. Q., Henry, T. D., Traverse, J. H., Pepine, C. J., Anderson, R. D., Berceli, S., Willerson, J. T., Muthupillai, R., Gahremanpour, A. A., Raveendran, G., Velazquez, O. C., Hare, J. M., Schulman, I. H., Kasi, V. S., Hiatt, W. R., Ambale-Venkatesh, B., Lima, J. A., Taylor, D. A., Resende, M. M., Gee, A. P., Durett, A. G., Bloom, J., Richman, S., G'Sell, P., Williams, S., Khan, F., Ross, E. G., Santoso, M. R., Goldman, J., Leach, D., Handberg, E., Cheong, B. Y., Piece, N. A., Difede, D., Bruhn-Ding, B., Caldwell, E., Bettencourt, J., Lai, D., Piller, L. B., Simpson, L. M., Cohen, M., Sayre, S. L., Vojvodic, R. W., Moyé, L., Ebert, R. F., Simari, R. D., Hirsch, A. T. 2017

    Abstract

    Atherosclerotic peripheral artery disease affects 8% to 12% of Americans >65 years of age and is associated with a major decline in functional status, increased myocardial infarction and stroke rates, and increased risk of ischemic amputation. Current treatment strategies for claudication have limitations. PACE (Patients With Intermittent Claudication Injected With ALDH Bright Cells) is a National Heart, Lung, and Blood Institute-sponsored, randomized, double-blind, placebo-controlled, phase 2 exploratory clinical trial designed to assess the safety and efficacy of autologous bone marrow-derived aldehyde dehydrogenase bright (ALDHbr) cells in patients with peripheral artery disease and to explore associated claudication physiological mechanisms.All participants, randomized 1:1 to receive ALDHbr cells or placebo, underwent bone marrow aspiration and isolation of ALDHbr cells, followed by 10 injections into the thigh and calf of the index leg. The coprimary end points were change from baseline to 6 months in peak walking time (PWT), collateral count, peak hyperemic popliteal flow, and capillary perfusion measured by magnetic resonance imaging, as well as safety.A total of 82 patients with claudication and infrainguinal peripheral artery disease were randomized at 9 sites, of whom 78 had analyzable data (57 male, 21 female patients; mean age, 66±9 years). The mean±SEM differences in the change over 6 months between study groups for PWT (0.9±0.8 minutes; 95% confidence interval [CI] -0.6 to 2.5; P=0.238), collateral count (0.9±0.6 arteries; 95% CI, -0.2 to 2.1; P=0.116), peak hyperemic popliteal flow (0.0±0.4 mL/s; 95% CI, -0.8 to 0.8; P=0.978), and capillary perfusion (-0.2±0.6%; 95% CI, -1.3 to 0.9; P=0.752) were not significant. In addition, there were no significant differences for the secondary end points, including quality-of-life measures. There were no adverse safety outcomes. Correlative relationships between magnetic resonance imaging measures and PWT were not significant. A post hoc exploratory analysis suggested that ALDHbr cell administration might be associated with an increase in the number of collateral arteries (1.5±0.7; 95% CI, 0.1-2.9; P=0.047) in participants with completely occluded femoral arteries.ALDHbr cell administration did not improve PWT or magnetic resonance outcomes, and the changes in PWT were not associated with the anatomic or physiological magnetic resonance imaging end points. Future peripheral artery disease cell therapy investigational trial design may be informed by new anatomic and perfusion insights.URL: http://www.clinicaltrials.gov. Unique identifier: NCT01774097.

    View details for DOI 10.1161/CIRCULATIONAHA.116.025707

    View details for PubMedID 28209728

  • High-Density Lipoprotein Nanoparticle Imaging in Atherosclerotic Vascular Disease. JACC. Basic to translational science Leeper, N. J., Park, S. M., Smith, B. R. 2017; 2 (1): 98-100

    Abstract

    Nanoparticles promise to advance the field of cardiovascular theranostics. However, their sustained and targeted delivery remains an important obstacle. The body synthesizes some "natural" nanoparticles, including high-density lipoprotein (HDL), which may home to the atherosclerotic plaque and promote cholesterol efflux. In a recent article published in JACC: Cardiovascular Imaging, investigators generated modified, radiolabeled HDL nanoparticles and confirmed they accumulated in atherosclerotic lesions from several different species. These approaches hold promise for the noninvasive diagnosis of vulnerable plaque and in the stratification of patients in whom HDL-mimetic therapy may have a clinical benefit.

    View details for DOI 10.1016/j.jacbts.2017.01.005

    View details for PubMedID 30167557

    View details for PubMedCentralID PMC6113536

  • MicroRNA-210 Enhances Fibrous Cap Stability in Advanced Atherosclerotic Lesions CIRCULATION RESEARCH Eken, S. M., Jin, H., Chernogubova, E., Li, Y., Simon, N., Sun, C., Korzunowicz, G., Busch, A., Backlund, A., Osterholm, C., Razuvaev, A., Renne, T., Eckstein, H. H., Pelisek, J., Eriksson, P., Diez, M. G., Matic, L. P., Schellinger, I. N., Raaz, U., Leeper, N. J., Hansson, G. K., Paulsson-Berne, G., Hedin, U., Maegdefessel, L. 2017; 120 (4): 633-?

    Abstract

    In the search for markers and modulators of vascular disease, microRNAs (miRNAs) have emerged as potent therapeutic targets.To investigate miRNAs of clinical interest in patients with unstable carotid stenosis at risk of stroke.Using patient material from the BiKE (Biobank of Karolinska Endarterectomies), we profiled miRNA expression in patients with stable versus unstable carotid plaque. A polymerase chain reaction-based miRNA array of plasma, sampled at the carotid lesion site, identified 8 deregulated miRNAs (miR-15b, miR-29c, miR-30c/d, miR-150, miR-191, miR-210, and miR-500). miR-210 was the most significantly downregulated miRNA in local plasma material. Laser capture microdissection and in situ hybridization revealed a distinct localization of miR-210 in fibrous caps. We confirmed that miR-210 directly targets the tumor suppressor gene APC (adenomatous polyposis coli), thereby affecting Wnt (Wingless-related integration site) signaling and regulating smooth muscle cell survival, as well as differentiation in advanced atherosclerotic lesions. Substantial changes in arterial miR-210 were detectable in 2 rodent models of vascular remodeling and plaque rupture. Modulating miR-210 in vitro and in vivo improved fibrous cap stability with implications for vascular disease.An unstable carotid plaque at risk of stroke is characterized by low expression of miR-210. miR-210 contributes to stabilizing carotid plaques through inhibition of APC, ensuring smooth muscle cell survival. We present local delivery of miR-210 as a therapeutic approach for prevention of atherothrombotic vascular events.

    View details for DOI 10.1161/CIRCRESAHA.116.309318

    View details for Web of Science ID 000394446200016

    View details for PubMedID 27895035

  • Baseline assessment and comparison of arterial anatomy, hyperemic flow, and skeletal muscle perfusion in peripheral artery disease: The Cardiovascular Cell Therapy Research Network "Patients with Intermittent Claudication Injected with ALDH Bright Cells" (CCTRN PACE) study AMERICAN HEART JOURNAL Venkatesh, B. A., Nauffal, V., Noda, C., Fujii, T., Yang, P. C., Bettencourt, J., Ricketts, E. P., Murphy, M., Leeper, N. J., Moye, L., Ebert, R. F., Muthupillai, R., Bluemke, D. A., Perin, E. C., Hirsch, A. T., Lima, J. A. 2017; 183: 24-34

    Abstract

    Peripheral artery disease (PAD) is important to public health as a major contributor to cardiovascular morbidity and mortality. Recent developments in magnetic resonance imaging (MRI) techniques permit improved assessment of PAD anatomy and physiology, and may serve as surrogate end points after proangiogenic therapies.The PACE study is a randomized, double-blind, placebo-controlled clinical trial designed to assess the physiologic impact and potential clinical efficacy of autologous bone marrow-derived ALDH(br) stem cells. The primary MRI end points of the study are as follows: (1) total collateral count, (2) calf muscle plasma volume (a measure of capillary perfusion) by dynamic contrast-enhanced MRI, and (3) peak hyperemic popliteal flow by phase-contrast MRI (PC-MRI).The interreader and intrareader and test-retest results demonstrated good-to-excellent reproducibility (interclass correlation coefficient range 0.61-0.98) for all magnetic resonance measures. The PAD participants (n=82) had lower capillary perfusion measured by calf muscle plasma volume (3.8% vs 5.6%) and peak hyperemic popliteal flow (4.1 vs 13.5mL/s) as compared with the healthy participants (n=16), with a significant level of collateralization.Reproducibility of the MRI primary end points in PACE was very good to excellent. The PAD participants exhibited decreased calf muscle capillary perfusion as well as arterial flow reserve when compared with healthy participants. The MRI tools used in PACE may advance PAD science by enabling accurate measurement of PAD microvascular anatomy and perfusion before and after stem cell or other PAD therapies.

    View details for DOI 10.1016/j.ahj.2016.09.013

    View details for PubMedID 27979038

  • High-Density Lipoprotein Nanoparticle Imaging in Atherosclerotic Vascular Disease JACC: Basic to Translational Science Leeper, N. J., Park, S., Smith, B. R. 2017; 2 (1): 98-100
  • Association Between Androgen Deprivation Therapy and Risk of Dementia JAMA ONCOLOGY Nead, K. T., Gaskin, G., Chester, C., Swisher-McClure, S., Leeper, N. J., Shah, N. H. 2017; 3 (1): 49-55

    Abstract

    A growing body of evidence supports a link between androgen deprivation therapy (ADT) and cognitive dysfunction, including Alzheimer disease. However, it is currently unknown whether ADT may contribute to the risk of dementia more broadly.To use an informatics approach to examine the association of ADT as a treatment for prostate cancer with the subsequent development of dementia (eg, senile dementia, vascular dementia, frontotemporal dementia, and Alzheimer dementia).In this cohort study, a text-processing method was used to analyze electronic medical record data from an academic medical center from 1994 to 2013, with a median follow-up of 3.4 years (interquartile range, 1.0-7.2 years). We identified 9455 individuals with prostate cancer who were 18 years or older at diagnosis with data recorded in the electronic health record and follow-up after diagnosis. We excluded 183 patients with a previous diagnosis of dementia. Our final cohort comprised 9272 individuals with prostate cancer, including 1826 men (19.7%) who received ADT.We tested the effect of ADT on the risk of dementia using propensity score-matched Cox proportional hazards regression models and Kaplan-Meier survival analysis.Among 9272 men with prostate cancer (mean [SD] age, 66.9 [10.9] years; 5450 [58.8%] white), there was a statistically significant association between use of ADT and risk of dementia (hazard ratio, 2.17; 95% CI, 1.58-2.99; P < .001). In sensitivity analyses, results were similar when excluding patients with Alzheimer disease (hazard ratio, 2.32; 95% CI, 1.73-3.12; P < .001). The absolute increased risk of developing dementia among those who received ADT was 4.4% at 5 years (7.9% among those who received ADT vs 3.5% in those who did not receive ADT). Analyses stratified by duration of ADT found that individuals with at least 12 months of ADT use had the greatest absolute increased risk of dementia (hazard ratio, 2.36; 95% CI, 1.64-3.38; P < .001). Kaplan-Meier analysis demonstrated that ADT users 70 years or older had the lowest cumulative probability of remaining dementia free (log-rank P < .001).Androgen deprivation therapy in the treatment of prostate cancer may be associated with an increased risk of dementia. This finding should be further evaluated in prospective studies.

    View details for DOI 10.1001/jamaoncol.2016.3662

    View details for Web of Science ID 000394257300011

  • Administration of ALDH Bright Cells to Patients With Intermittent Claudication: The NHLBI CCTRN PACE Trial Perin, E. C., Murphy, M., March, K., Bolli, R., Leeper, N. J., Yang, P. C., Alexander, J., Henry, T. D., Traverse, J. H., Pepine, C. J., Willerson, J. T., Velasquez, O., Hare, J. M., Kasi, V. S., Lima, J. A., Hiatt, W. R., Taylor, D. A., Gee, A. P., Moye, L., Ebert, R. F., Simari, R. D., Hirsch, A. T. LIPPINCOTT WILLIAMS & WILKINS. 2016: E709
  • Genome-Wide Association Studies Candidate Gene to Dual Modifier of Nonalcoholic Steatohepatitis and Atherosclerosis. JACC. Basic to translational science Miller, C. L., Leeper, N. J. 2016; 1 (7): 680–83

    Abstract

    Non-alcoholic steatohepatitis (NASH) is a common disease involving chronic accumulation of fat and inflammation in the liver, often leading to advanced fibrosis, cirrhosis and cancer. It is known that NASH shares many features with atherosclerosis, however, there are still no effective therapeutics. In a recent study published in Nature, investigators demonstrate that mice lacking a high-density lipoprotein (HDL)-associated gene were surprisingly protected from both steatohepatitis and atherosclerosis through the stabilization of the liver X receptor (LXR). This work reveals a timely candidate target for two highly prevalent cardiovascular diseases.

    View details for PubMedID 28603781

  • The use of machine learning for the identification of peripheral artery disease and future mortality risk. Journal of vascular surgery Ross, E. G., Shah, N. H., Dalman, R. L., Nead, K. T., Cooke, J. P., Leeper, N. J. 2016; 64 (5): 1515-1522 e3

    Abstract

    A key aspect of the precision medicine effort is the development of informatics tools that can analyze and interpret "big data" sets in an automated and adaptive fashion while providing accurate and actionable clinical information. The aims of this study were to develop machine learning algorithms for the identification of disease and the prognostication of mortality risk and to determine whether such models perform better than classical statistical analyses.Focusing on peripheral artery disease (PAD), patient data were derived from a prospective, observational study of 1755 patients who presented for elective coronary angiography. We employed multiple supervised machine learning algorithms and used diverse clinical, demographic, imaging, and genomic information in a hypothesis-free manner to build models that could identify patients with PAD and predict future mortality. Comparison was made to standard stepwise linear regression models.Our machine-learned models outperformed stepwise logistic regression models both for the identification of patients with PAD (area under the curve, 0.87 vs 0.76, respectively; P = .03) and for the prediction of future mortality (area under the curve, 0.76 vs 0.65, respectively; P = .10). Both machine-learned models were markedly better calibrated than the stepwise logistic regression models, thus providing more accurate disease and mortality risk estimates.Machine learning approaches can produce more accurate disease classification and prediction models. These tools may prove clinically useful for the automated identification of patients with highly morbid diseases for which aggressive risk factor management can improve outcomes.

    View details for DOI 10.1016/j.jvs.2016.04.026

    View details for PubMedID 27266594

    View details for PubMedCentralID PMC5079774

  • Influence of age on androgen deprivation therapy-associated Alzheimer's disease SCIENTIFIC REPORTS Nead, K. T., Gaskin, G., Chester, C., Swisher-McClure, S., Dudley, J. T., Leeper, N. J., Shah, N. H. 2016; 6

    Abstract

    We recently found an association between androgen deprivation therapy (ADT) and Alzheimer's disease. As Alzheimer's disease is a disease of advanced age, we hypothesize that older individuals on ADT may be at greatest risk. We conducted a retrospective multi-institutional analysis among 16,888 individuals with prostate cancer using an informatics approach. We tested the effect of ADT on Alzheimer's disease using Kaplan-Meier age stratified analyses in a propensity score matched cohort. We found a lower cumulative probability of remaining Alzheimer's disease-free between non-ADT users age ≥70 versus those age <70 years (p < 0.001) and between ADT versus non-ADT users ≥70 years (p = 0.034). The 5-year probability of developing Alzheimer's disease was 2.9%, 1.9% and 0.5% among ADT users ≥70, non-ADT users ≥70 and individuals <70 years, respectively. Compared to younger individuals older men on ADT may have the greatest absolute Alzheimer's disease risk. Future work should investigate the ADT Alzheimer's disease association in advanced age populations given the greater potential clinical impact.

    View details for DOI 10.1038/srep35695

    View details for Web of Science ID 000385588200002

    View details for PubMedID 27752112

    View details for PubMedCentralID PMC5067668

  • Association Between Androgen Deprivation Therapy and Risk of Dementia. JAMA oncology Nead, K. T., Gaskin, G., Chester, C., Swisher-McClure, S., Leeper, N. J., Shah, N. H. 2016

    Abstract

    A growing body of evidence supports a link between androgen deprivation therapy (ADT) and cognitive dysfunction, including Alzheimer disease. However, it is currently unknown whether ADT may contribute to the risk of dementia more broadly.To use an informatics approach to examine the association of ADT as a treatment for prostate cancer with the subsequent development of dementia (eg, senile dementia, vascular dementia, frontotemporal dementia, and Alzheimer dementia).In this cohort study, a text-processing method was used to analyze electronic medical record data from an academic medical center from 1994 to 2013, with a median follow-up of 3.4 years (interquartile range, 1.0-7.2 years). We identified 9455 individuals with prostate cancer who were 18 years or older at diagnosis with data recorded in the electronic health record and follow-up after diagnosis. We excluded 183 patients with a previous diagnosis of dementia. Our final cohort comprised 9272 individuals with prostate cancer, including 1826 men (19.7%) who received ADT.We tested the effect of ADT on the risk of dementia using propensity score-matched Cox proportional hazards regression models and Kaplan-Meier survival analysis.Among 9272 men with prostate cancer (mean [SD] age, 66.9 [10.9] years; 5450 [58.8%] white), there was a statistically significant association between use of ADT and risk of dementia (hazard ratio, 2.17; 95% CI, 1.58-2.99; P < .001). In sensitivity analyses, results were similar when excluding patients with Alzheimer disease (hazard ratio, 2.32; 95% CI, 1.73-3.12; P < .001). The absolute increased risk of developing dementia among those who received ADT was 4.4% at 5 years (7.9% among those who received ADT vs 3.5% in those who did not receive ADT). Analyses stratified by duration of ADT found that individuals with at least 12 months of ADT use had the greatest absolute increased risk of dementia (hazard ratio, 2.36; 95% CI, 1.64-3.38; P < .001). Kaplan-Meier analysis demonstrated that ADT users 70 years or older had the lowest cumulative probability of remaining dementia free (log-rank P < .001).Androgen deprivation therapy in the treatment of prostate cancer may be associated with an increased risk of dementia. This finding should be further evaluated in prospective studies.

    View details for DOI 10.1001/jamaoncol.2016.3662

    View details for PubMedID 27737437

  • The Promise and Challenge of Induced Pluripotent Stem Cells for Cardiovascular Applications. JACC. Basic to translational science Youssef, A. A., Ross, E. G., Bolli, R., Pepine, C. J., Leeper, N. J., Yang, P. C. 2016; 1 (6): 510-523

    Abstract

    The recent discovery of human-induced pluripotent stem cells (iPSCs) has revolutionized the field of stem cells. iPSCs have demonstrated that biological development is not an irreversible process and that mature adult somatic cells can be induced to become pluripotent. This breakthrough is projected to advance our current understanding of many disease processes and revolutionize the approach to effective therapeutics. Despite the great promise of iPSCs, many translational challenges still remain. In this article, we review the basic concept of induction of pluripotency as a novel approach to understand cardiac regeneration, cardiovascular disease modeling and drug discovery. We critically reflect on the current results of preclinical and clinical studies using iPSCs for these applications with appropriate emphasis on the challenges facing clinical translation.

    View details for DOI 10.1016/j.jacbts.2016.06.010

    View details for PubMedID 28580434

  • The role of necroptosis in atherosclerotic disease. JACC. Basic to translational science Leeper, N. J. 2016; 1 (6): 548–50

    Abstract

    It is now known that cells don't always die by apoptosis, but can also undergo a process known as programmed cell necrosis, or necroptosis. In a study recently published in Science Advances, investigators reported that this pro-inflammatory process is active in human atherosclerosis, may promote growth of the necrotic core, and may serve as a novel molecular imaging and translational therapeutic target. These findings represent a major step in our goal to reduce coronary disease and stroke.

    View details for PubMedID 28480338

  • Use of Predictive Analytics for the Identification of Latent Vascular Disease and Future Adverse Cardiac Events Ross, E. G., Shah, N., Dalman, R. L., Nead, K., Leeper, N. J. MOSBY-ELSEVIER. 2016: 28S–29S
  • Use of Machine Learning to Accurately Predict Adverse Events in Patients with Peripheral Artery Disease Using Electronic Health Record Data Ross, E. G., Shah, N., Leeper, N. SAGE PUBLICATIONS LTD. 2016: 290
  • Statin Intensity or Achieved LDL? Practice-based Evidence for the Evaluation of New Cholesterol Treatment Guidelines PLOS ONE Ross, E. G., Shah, N., Leeper, N. 2016; 11 (5)

    Abstract

    The recently updated American College of Cardiology/American Heart Association cholesterol treatment guidelines outline a paradigm shift in the approach to cardiovascular risk reduction. One major change included a recommendation that practitioners prescribe fixed dose statin regimens rather than focus on specific LDL targets. The goal of this study was to determine whether achieved LDL or statin intensity was more strongly associated with major adverse cardiac events (MACE) using practice-based data from electronic health records (EHR).We analyzed the EHR data of more than 40,000 adult patients on statin therapy between 1995 and 2013. Demographic and clinical variables were extracted from coded data and unstructured clinical text. To account for treatment selection bias we performed propensity score stratification as well as 1:1 propensity score matched analyses. Conditional Cox proportional hazards modeling was used to identify variables associated with MACE.We identified 7,373 adults with complete data whose cholesterol appeared to be actively managed. In a stratified propensity score analysis of the entire cohort over 3.3 years of follow-up, achieved LDL was a significant predictor of MACE outcome (Hazard Ratio 1.1; 95% confidence interval, 1.05-1.2; P < 0.0004), while statin intensity was not. In a 1:1 propensity score matched analysis performed to more aggressively control for covariate balance between treatment groups, achieved LDL remained significantly associated with MACE (HR 1.3; 95% CI, 1.03-1.7; P = 0.03) while treatment intensity again was not a significant predictor.Using EHR data we found that on-treatment achieved LDL level was a significant predictor of MACE. Statin intensity alone was not associated with outcomes. These findings imply that despite recent guidelines, achieved LDL levels are clinically important and LDL titration strategies warrant further investigation in clinical trials.

    View details for DOI 10.1371/journal.pone.0154952

    View details for Web of Science ID 000376882500009

    View details for PubMedID 27227451

    View details for PubMedCentralID PMC4881915

  • Androgen Deprivation Therapy and Future Alzheimer's Disease Risk. Journal of clinical oncology Nead, K. T., Gaskin, G., Chester, C., Swisher-McClure, S., Dudley, J. T., Leeper, N. J., Shah, N. H. 2016; 34 (6): 566-571

    Abstract

    To test the association of androgen deprivation therapy (ADT) in the treatment of prostate cancer with subsequent Alzheimer's disease risk.We used a previously validated and implemented text-processing pipeline to analyze electronic medical record data in a retrospective cohort of patients at Stanford University and Mt. Sinai hospitals. Specifically, we extracted International Classification of Diseases-9th revision diagnosis and Current Procedural Terminology codes, medication lists, and positive-present mentions of drug and disease concepts from all clinical notes. We then tested the effect of ADT on risk of Alzheimer's disease using 1:5 propensity score-matched and traditional multivariable-adjusted Cox proportional hazards models. The duration of ADT use was also tested for association with Alzheimer's disease risk.There were 16,888 individuals with prostate cancer meeting all inclusion and exclusion criteria, with 2,397 (14.2%) receiving ADT during a median follow-up period of 2.7 years (interquartile range, 1.0-5.4 years). Propensity score-matched analysis (hazard ratio, 1.88; 95% CI, 1.10 to 3.20; P = .021) and traditional multivariable-adjusted Cox regression analysis (hazard ratio, 1.66; 95% CI, 1.05 to 2.64; P = .031) both supported a statistically significant association between ADT use and Alzheimer's disease risk. We also observed a statistically significant increased risk of Alzheimer's disease with increasing duration of ADT (P = .016).Our results support an association between the use of ADT in the treatment of prostate cancer and an increased risk of Alzheimer's disease in a general population cohort. This study demonstrates the utility of novel methods to analyze electronic medical record data to generate practice-based evidence.

    View details for DOI 10.1200/JCO.2015.63.6266

    View details for PubMedID 26644522

  • Reply. Gastroenterology Shah, N. H., Cooke, J. P., Leeper, N. J. 2016; 150 (2): 528-?

    View details for DOI 10.1053/j.gastro.2015.12.017

    View details for PubMedID 26721609

  • Proton pump inhibitors and vascular function: A prospective cross-over pilot study VASCULAR MEDICINE Ghebremariam, Y. T., Cooke, J. P., Khan, F., Thakker, R. N., Chang, P., Shah, N. H., Nead, K. T., Leeper, N. J. 2015; 20 (4): 309-316

    Abstract

    Proton pump inhibitors (PPIs) are commonly used drugs for the treatment of gastric reflux. Recent retrospective cohorts and large database studies have raised concern that the use of PPIs is associated with increased cardiovascular (CV) risk. However, there is no prospective clinical study evaluating whether the use of PPIs directly causes CV harm. We conducted a controlled, open-label, cross-over pilot study among 21 adults aged 18 and older who are healthy (n=11) or have established clinical cardiovascular disease (n=10). Study subjects were assigned to receive a PPI (Prevacid; 30 mg) or a placebo pill once daily for 4 weeks. After a 2-week washout period, participants were crossed over to receive the alternate treatment for the ensuing 4 weeks. Subjects underwent evaluation of vascular function (by the EndoPAT technique) and had plasma levels of asymmetric dimethylarginine (ADMA, an endogenous inhibitor of endothelial function previously implicated in PPI-mediated risk) measured prior to and after each treatment interval. We observed a marginal inverse correlation between the EndoPAT score and plasma levels of ADMA (r = -0.364). Subjects experienced a greater worsening in plasma ADMA levels while on PPI than on placebo, and this trend was more pronounced amongst those subjects with a history of vascular disease. However, these trends did not reach statistical significance, and PPI use was also not associated with an impairment in flow-mediated vasodilation during the course of this study. In conclusion, in this open-label, cross-over pilot study conducted among healthy subjects and coronary disease patients, PPI use did not significantly influence vascular endothelial function. Larger, long-term and blinded trials are needed to mechanistically explain the correlation between PPI use and adverse clinical outcomes, which has recently been reported in retrospective cohort studies.

    View details for DOI 10.1177/1358863X14568444

    View details for Web of Science ID 000359414300001

    View details for PubMedID 25835348

    View details for PubMedCentralID PMC4572842

  • Text-mining methods applied to clinical records support an association between androgen deprivation therapy and subsequent cardiometabolic disease Nead, K. T., Gaskin, G. L., Chester, C., Shah, N. H., Leeper, N. J. AMER ASSOC CANCER RESEARCH. 2015
  • Proton Pump Inhibitor Usage and the Risk of Myocardial Infarction in the General Population PLOS ONE Shah, N. H., LePendu, P., Bauer-Mehren, A., Ghebremariam, Y. T., Iyer, S. V., Marcus, J., Nead, K. T., Cooke, J. P., Leeper, N. J. 2015; 10 (6)

    Abstract

    Proton pump inhibitors (PPIs) have been associated with adverse clinical outcomes amongst clopidogrel users after an acute coronary syndrome. Recent pre-clinical results suggest that this risk might extend to subjects without any prior history of cardiovascular disease. We explore this potential risk in the general population via data-mining approaches.Using a novel approach for mining clinical data for pharmacovigilance, we queried over 16 million clinical documents on 2.9 million individuals to examine whether PPI usage was associated with cardiovascular risk in the general population.In multiple data sources, we found gastroesophageal reflux disease (GERD) patients exposed to PPIs to have a 1.16 fold increased association (95% CI 1.09-1.24) with myocardial infarction (MI). Survival analysis in a prospective cohort found a two-fold (HR = 2.00; 95% CI 1.07-3.78; P = 0.031) increase in association with cardiovascular mortality. We found that this association exists regardless of clopidogrel use. We also found that H2 blockers, an alternate treatment for GERD, were not associated with increased cardiovascular risk; had they been in place, such pharmacovigilance algorithms could have flagged this risk as early as the year 2000.Consistent with our pre-clinical findings that PPIs may adversely impact vascular function, our data-mining study supports the association of PPI exposure with risk for MI in the general population. These data provide an example of how a combination of experimental studies and data-mining approaches can be applied to prioritize drug safety signals for further investigation.

    View details for DOI 10.1371/journal.pone.0124653

    View details for Web of Science ID 000355979500007

    View details for PubMedID 26061035

    View details for PubMedCentralID PMC4462578

  • What Matters Most, Statin Intensity or Achieved LDL? - Evaluating Concordance of AHA/ACC Guidelines for Statin Use with Practice Outcomes at Stanford Hospital & Clinics Gyang, E., Shah, N., Leeper, N. SAGE PUBLICATIONS LTD. 2015: 295
  • Cyclin-Dependent Kinase Inhibitor 2B Regulates Transforming Growth Factor Beta 1 Mediated Smooth Muscle Cell Recruitment to Ischemic Blood Vessels Nanda, V., Downing, K., Kojima, Y., DiRenzo, D., Dalman, J., Connolly, A. J., Maegdefessel, L., Perisic, L., Dandona, S., Guo, L., Davis, H. R., Virmani, R., Spin, J., Leeper, N. SAGE PUBLICATIONS LTD. 2015: 274
  • Using clinical data text-mining analysis to examine the association between androgen deprivation therapy and depression. Nead, K. T., Gaskin, G. L., Chester, C., Leeper, N. J., Shah, N. H. AMER SOC CLINICAL ONCOLOGY. 2015
  • Improved Reclassification of Mortality Risk by Assessment of Physical Activity in Patients Referred for Exercise Testing AMERICAN JOURNAL OF MEDICINE Myers, J., Nead, K. T., Chang, P., Abella, J., Kokkinos, P., Leeper, N. J. 2015; 128 (4): 396-402

    Abstract

    Inability to meet minimal guidelines on physical activity is associated with poor health outcomes, but quantifying activity can be complex. We studied whether a simple question regarding participation in regular activity improves risk classification for all-cause mortality.Maximal exercise testing was performed in 6962 patients (mean age, 58.9 ± 11 years) for clinical reasons. Subjects also were assessed for participation in regular activity using a simple yes/no response to meeting minimal recommendations on activity. The incremental value of adding a simple physical activity assessment to clinical, demographic, and exercise test information to predict mortality was determined using Cox proportional hazards models, net reclassification improvement, and integrated discrimination index during a mean follow-up of 9.7 ± 4 years.Subjects who did not meet the minimal guidelines on activity had a lower exercise capacity (7.4 ± 4.3 vs 9.1 ± 3.6 metabolic equivalents, P < .0001) and a higher annual mortality rate (2.42% vs 1.71%, P < .001). Not meeting activity guidelines was associated with an age-adjusted 36% higher risk of mortality (hazard ratio, 1.36; 95% confidence interval, 1.22-1.51, P < .0001). Among clinical and exercise test variables, fitness had the highest C-index for predicting mortality (0.72, P < .001). The addition of physical activity classification to a model including traditional risk factors resulted in a net reclassification improvement of 22.8% (P < .001); adding fitness to the traditional risk factor model resulted in a net reclassification improvement of 43.5% (P < .001).The addition of a simple assessment of physical activity status significantly improves reclassification of risk for all-cause mortality among patients who are referred for exercise testing.

    View details for DOI 10.1016/j.amjmed.2014.10.061

    View details for Web of Science ID 000351365600029

    View details for PubMedID 25511076

  • Effect of physical activity assessment on prognostication for peripheral artery disease and mortality. Mayo Clinic proceedings Chang, P., Nead, K. T., Olin, J. W., Myers, J., Cooke, J. P., Leeper, N. J. 2015; 90 (3): 339-345

    Abstract

    To examine whether a simple question about the performance of regular vigorous activity is associated with peripheral artery disease (PAD) and mortality.A total of 1288 individuals undergoing nonemergency coronary angiography were assessed for participation in regular vigorous activity by questionnaire. Data on demographic characteristics, ankle-brachial indexes, and cardiovascular outcomes were prospectively collected.Compared with those who denied participation in regular vigorous activity, those who reported participation were less likely to have PAD (odds ratio, 0.58; 95% CI, 0.39-0.86), had higher ankle-brachial indexes, had better Walking Impairment Questionnaire scores (P<.001), and experienced reduced all-cause mortality rates (hazard ratio, 0.48; 95% CI, 0.31-0.74). When added to the Framingham Risk Score, the response improved the net reclassification index for all-cause (32.6%) and cardiovascular (32.0%) mortality.Among at-risk individuals, regular vigorous activity is associated with decreased PAD and all-cause mortality. Simple and readily available, a single yes/no query about participation in regular vigorous exercise could be used to improve risk stratification.

    View details for DOI 10.1016/j.mayocp.2014.12.016

    View details for PubMedID 25649965

  • Proton Pump Inhibitor Usage and the Risk of Myocardial Infarction in the General Population. PloS one Shah, N. H., LePendu, P., Bauer-Mehren, A., Ghebremariam, Y. T., Iyer, S. V., Marcus, J., Nead, K. T., Cooke, J. P., Leeper, N. J. 2015; 10 (6)

    Abstract

    Proton pump inhibitors (PPIs) have been associated with adverse clinical outcomes amongst clopidogrel users after an acute coronary syndrome. Recent pre-clinical results suggest that this risk might extend to subjects without any prior history of cardiovascular disease. We explore this potential risk in the general population via data-mining approaches.Using a novel approach for mining clinical data for pharmacovigilance, we queried over 16 million clinical documents on 2.9 million individuals to examine whether PPI usage was associated with cardiovascular risk in the general population.In multiple data sources, we found gastroesophageal reflux disease (GERD) patients exposed to PPIs to have a 1.16 fold increased association (95% CI 1.09-1.24) with myocardial infarction (MI). Survival analysis in a prospective cohort found a two-fold (HR = 2.00; 95% CI 1.07-3.78; P = 0.031) increase in association with cardiovascular mortality. We found that this association exists regardless of clopidogrel use. We also found that H2 blockers, an alternate treatment for GERD, were not associated with increased cardiovascular risk; had they been in place, such pharmacovigilance algorithms could have flagged this risk as early as the year 2000.Consistent with our pre-clinical findings that PPIs may adversely impact vascular function, our data-mining study supports the association of PPI exposure with risk for MI in the general population. These data provide an example of how a combination of experimental studies and data-mining approaches can be applied to prioritize drug safety signals for further investigation.

    View details for DOI 10.1371/journal.pone.0124653

    View details for PubMedID 26061035

    View details for PubMedCentralID PMC4462578

  • Therapeutic Potential of Modulating MicroRNA in Peripheral Artery Disease CURRENT VASCULAR PHARMACOLOGY Hamburg, N. M., Leeper, N. J. 2015; 13 (3): 316–23

    Abstract

    Peripheral artery disease (PAD) produces significant disability attributable to lower extremity ischemia. Limited treatment modalities exist to ameliorate clinical symptoms in patients with PAD. Growing evidence links microRNAs to key processes that govern disease expression in PAD including angiogenesis, endothelial function, inflammation, vascular regeneration, vascular smooth muscle cell function, restenosis, and mitochondrial function. MicroRNAs have been identified in circulation and may serve as novel biomarkers in PAD. This article reviews the potential contribution of microRNA to key pathways of disease development in PAD that may lead to microRNA-based diagnostic and therapeutic approaches.

    View details for DOI 10.2174/15701611113119990014

    View details for Web of Science ID 000357694900005

    View details for PubMedID 23713861

    View details for PubMedCentralID PMC4886469

  • MicroRNA Regulation of Vascular Smooth Muscle Function and Phenotype Early Career Committee Contribution ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Maegdefessel, L., Rayner, K. J., Leeper, N. J. 2015; 35 (1): 2-6

    View details for DOI 10.1161/ATVBAHA.114.304877

    View details for Web of Science ID 000346561100003

    View details for PubMedID 25520518

  • Oxido-reductive regulation of vascular remodeling by receptor tyrosine kinase ROS1 JOURNAL OF CLINICAL INVESTIGATION Ali, Z. A., Perez, V. D., Yuan, K., Orcholski, M., Pan, S., Qi, W., Chopra, G., Adams, C., Kojima, Y., Leeper, N. J., Qu, X., Zaleta-Rivera, K., Kato, K., Yamada, Y., Oguri, M., Kuchinsky, A., Hazen, S. L., Jukema, J. W., Ganesh, S. K., Nabe, E. G., Channon, K., Leon, M. B., Charest, A., Quertermous, T., Ashley, E. A. 2014; 124 (12): 5159-5174

    Abstract

    Angioplasty and stenting is the primary treatment for flow-limiting atherosclerosis; however, this strategy is limited by pathological vascular remodeling. Using a systems approach, we identified a role for the network hub gene glutathione peroxidase-1 (GPX1) in pathological remodeling following human blood vessel stenting. Constitutive deletion of Gpx1 in atherosclerotic mice recapitulated this phenotype of increased vascular smooth muscle cell (VSMC) proliferation and plaque formation. In an independent patient cohort, gene variant pair analysis identified an interaction of GPX1 with the orphan protooncogene receptor tyrosine kinase ROS1. A meta-analysis of the only genome-wide association studies of human neointima-induced in-stent stenosis confirmed the association of the ROS1 variant with pathological remodeling. Decreased GPX1 expression in atherosclerotic mice led to reductive stress via a time-dependent increase in glutathione, corresponding to phosphorylation of the ROS1 kinase activation site Y2274. Loss of GPX1 function was associated with both oxidative and reductive stress, the latter driving ROS1 activity via s-glutathiolation of critical residues of the ROS1 tyrosine phosphatase SHP-2. ROS1 inhibition with crizotinib and deglutathiolation of SHP-2 abolished GPX1-mediated increases in VSMC proliferation while leaving endothelialization intact. Our results indicate that GPX1-dependent alterations in oxido-reductive stress promote ROS1 activation and mediate vascular remodeling.

    View details for DOI 10.1172/JCI77484

    View details for Web of Science ID 000345677200011

    View details for PubMedID 25401476

  • Rationale and Design for PACE: Patients with Intermittent Claudication Injected with ALDH Bright Cells AMERICAN HEART JOURNAL Perin, E. C., Murphy, M., Cooke, J. P., Moye, L., Henry, T. D., Bettencourt, J., Gahremanpour, A., Leeper, N., Anderson, R. D., Hiatt, W. R., Lima, J. A., Venkatesh, B., Sayre, S. L., Vojvodic, R. W., Taylor, D. A., Ebert, R. F., Hirsch, A. T. 2014; 168 (5): 667-673

    Abstract

    Peripheral artery disease (PAD) is recognized as a public health issue because of its prevalence, functional limitations, and increased risk of systemic ischemic events. Current treatments for claudication, the primary symptom in patients with PAD, have limitations. Cells identified using cytosolic enzyme aldehyde dehydrogenase (ALDH) may benefit patients with severe PAD but has not been studied in patients with claudication. PACE is a randomized, double-blind, placebo-controlled clinical trial conducted by the Cardiovascular Cell Therapy Research Network to assess the safety and efficacy of autologous bone marrow-derived ALDH(br) cells delivered by direct intramuscular injections in 80 patients with symptom-limiting intermittent claudication. Eligible patients will have a significant stenosis or occlusion of infrainguinal arteries and a resting ankle-brachial index less than 0.90 and will be randomized 1:1 to cell or placebo treatment with a 1-year follow-up. The primary end points are the change in peak walking time and leg collateral arterial anatomy, calf muscle blood flow, and tissue perfusion as determined by magnetic resonance imaging at 6 months compared with baseline. The latter 3 measurements are new physiologic lower extremity tissue perfusion and PAD imaging-based end points that may help to quantify the biologic and mechanistic effects of cell therapy. This trial will collect important mechanistic and clinical information on the safety and efficacy of ALDH(br) cells in patients with claudication and provide valuable insight into the utility of advanced magnetic resonance imaging end points.

    View details for DOI 10.1016/j.ahj.2014.07.021

    View details for Web of Science ID 000344434300008

    View details for PubMedCentralID PMC4254580

  • Rationale and design for PACE: patients with intermittent claudication injected with ALDH bright cells. American heart journal Perin, E. C., Murphy, M., Cooke, J. P., Moyé, L., Henry, T. D., Bettencourt, J., Gahremanpour, A., Leeper, N., Anderson, R. D., Hiatt, W. R., Lima, J. A., Venkatesh, B., Sayre, S. L., Vojvodic, R. W., Taylor, D. A., Ebert, R. F., Hirsch, A. T. 2014; 168 (5): 667-673

    Abstract

    Peripheral artery disease (PAD) is recognized as a public health issue because of its prevalence, functional limitations, and increased risk of systemic ischemic events. Current treatments for claudication, the primary symptom in patients with PAD, have limitations. Cells identified using cytosolic enzyme aldehyde dehydrogenase (ALDH) may benefit patients with severe PAD but has not been studied in patients with claudication. PACE is a randomized, double-blind, placebo-controlled clinical trial conducted by the Cardiovascular Cell Therapy Research Network to assess the safety and efficacy of autologous bone marrow-derived ALDH(br) cells delivered by direct intramuscular injections in 80 patients with symptom-limiting intermittent claudication. Eligible patients will have a significant stenosis or occlusion of infrainguinal arteries and a resting ankle-brachial index less than 0.90 and will be randomized 1:1 to cell or placebo treatment with a 1-year follow-up. The primary end points are the change in peak walking time and leg collateral arterial anatomy, calf muscle blood flow, and tissue perfusion as determined by magnetic resonance imaging at 6 months compared with baseline. The latter 3 measurements are new physiologic lower extremity tissue perfusion and PAD imaging-based end points that may help to quantify the biologic and mechanistic effects of cell therapy. This trial will collect important mechanistic and clinical information on the safety and efficacy of ALDH(br) cells in patients with claudication and provide valuable insight into the utility of advanced magnetic resonance imaging end points.

    View details for DOI 10.1016/j.ahj.2014.07.021

    View details for PubMedID 25440794

  • Clinical and socioeconomic factors associated with unrecognized peripheral artery disease VASCULAR MEDICINE Chang, P., Nead, K. T., Olin, J. W., Cooke, J. P., Leeper, N. J. 2014; 19 (4): 289-296

    Abstract

    Peripheral artery disease (PAD) is a highly prevalent condition that frequently goes undetected and untreated. Socioeconomic factors associated with unrecognized PAD are not known. The ankle-brachial index (ABI) was calculated in 1656 study participants undergoing non-emergent coronary angiography with PAD defined as an ABI <0.9. Subjects were followed for mortality and cardiovascular outcomes. Compared to those without PAD, those with unrecognized PAD at enrollment were older, had higher rates of cardiovascular comorbidities, and had higher major adverse cardiovascular events (MACE) (p<0.03 for all). Among those enrolling without a reported history of PAD, there was a higher prevalence of PAD with decreasing income (p=0.004), education level (p<0.001), social isolation (p=0.027) and depression (p=0.034); 50% of these individuals reported symptoms suggestive of claudication. In conclusion, the prevalence of unrecognized PAD is high amongst a cohort of high-risk individuals referred for coronary angiography. A profile of lower socioeconomic status is associated with unrecognized PAD. These subjects will report symptoms suggestive of claudication and impaired walking ability when directly queried.

    View details for DOI 10.1177/1358863X14535475

    View details for Web of Science ID 000340161000006

  • Clinical and socioeconomic factors associated with unrecognized peripheral artery disease. Vascular medicine (London, England) Chang, P., Nead, K. T., Olin, J. W., Cooke, J. P., Leeper, N. J. 2014; 19 (4): 289-296

    Abstract

    Peripheral artery disease (PAD) is a highly prevalent condition that frequently goes undetected and untreated. Socioeconomic factors associated with unrecognized PAD are not known. The ankle-brachial index (ABI) was calculated in 1656 study participants undergoing non-emergent coronary angiography with PAD defined as an ABI <0.9. Subjects were followed for mortality and cardiovascular outcomes. Compared to those without PAD, those with unrecognized PAD at enrollment were older, had higher rates of cardiovascular comorbidities, and had higher major adverse cardiovascular events (MACE) (p<0.03 for all). Among those enrolling without a reported history of PAD, there was a higher prevalence of PAD with decreasing income (p=0.004), education level (p<0.001), social isolation (p=0.027) and depression (p=0.034); 50% of these individuals reported symptoms suggestive of claudication. In conclusion, the prevalence of unrecognized PAD is high amongst a cohort of high-risk individuals referred for coronary angiography. A profile of lower socioeconomic status is associated with unrecognized PAD. These subjects will report symptoms suggestive of claudication and impaired walking ability when directly queried.

    View details for DOI 10.1177/1358863X14535475

    View details for PubMedID 24872403

  • Coronary heart disease-associated variation in TCF21 disrupts a miR-224 binding site and miRNA-mediated regulation. PLoS genetics Miller, C. L., Haas, U., Diaz, R., Leeper, N. J., Kundu, R. K., Patlolla, B., Assimes, T. L., Kaiser, F. J., Perisic, L., Hedin, U., Maegdefessel, L., Schunkert, H., Erdmann, J., Quertermous, T., Sczakiel, G. 2014; 10 (3)

    Abstract

    Genome-wide association studies (GWAS) have identified chromosomal loci that affect risk of coronary heart disease (CHD) independent of classical risk factors. One such association signal has been identified at 6q23.2 in both Caucasians and East Asians. The lead CHD-associated polymorphism in this region, rs12190287, resides in the 3' untranslated region (3'-UTR) of TCF21, a basic-helix-loop-helix transcription factor, and is predicted to alter the seed binding sequence for miR-224. Allelic imbalance studies in circulating leukocytes and human coronary artery smooth muscle cells (HCASMC) showed significant imbalance of the TCF21 transcript that correlated with genotype at rs12190287, consistent with this variant contributing to allele-specific expression differences. 3' UTR reporter gene transfection studies in HCASMC showed that the disease-associated C allele has reduced expression compared to the protective G allele. Kinetic analyses in vitro revealed faster RNA-RNA complex formation and greater binding of miR-224 with the TCF21 C allelic transcript. In addition, in vitro probing with Pb2+ and RNase T1 revealed structural differences between the TCF21 variants in proximity of the rs12190287 variant, which are predicted to provide greater access to the C allele for miR-224 binding. miR-224 and TCF21 expression levels were anti-correlated in HCASMC, and miR-224 modulates the transcriptional response of TCF21 to transforming growth factor-β (TGF-β) and platelet derived growth factor (PDGF) signaling in an allele-specific manner. Lastly, miR-224 and TCF21 were localized in human coronary artery lesions and anti-correlated during atherosclerosis. Together, these data suggest that miR-224 interaction with the TCF21 transcript contributes to allelic imbalance of this gene, thus partly explaining the genetic risk for coronary heart disease associated at 6q23.2. These studies implicating rs12190287 in the miRNA-dependent regulation of TCF21, in conjunction with previous studies showing that this variant modulates transcriptional regulation through activator protein 1 (AP-1), suggests a unique bimodal level of complexity previously unreported for disease-associated variants.

    View details for DOI 10.1371/journal.pgen.1004263

    View details for PubMedID 24676100

    View details for PubMedCentralID PMC3967965

  • Coronary heart disease-associated variation in TCF21 disrupts a miR-224 binding site and miRNA-mediated regulation. PLoS genetics Miller, C. L., Haas, U., Diaz, R., Leeper, N. J., Kundu, R. K., Patlolla, B., Assimes, T. L., Kaiser, F. J., Perisic, L., Hedin, U., Maegdefessel, L., Schunkert, H., Erdmann, J., Quertermous, T., Sczakiel, G. 2014; 10 (3)

    View details for DOI 10.1371/journal.pgen.1004263

    View details for PubMedID 24676100

  • Transcriptional activation of hypoxia-inducible factor-1 (HIF-1) in myeloid cells promotes angiogenesis through VEGF and S100A8 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Ahn, G., Seita, J., Hong, B., Kim, Y., Bok, S., Lee, C., Kim, K. S., Lee, J. C., Leeper, N. J., Cooke, J. P., Kim, H. J., Kim, I. H., Weissman, I. L., Brown, J. M. 2014; 111 (7): 2698-2703

    Abstract

    Emerging evidence indicates that myeloid cells are essential for promoting new blood vessel formation by secreting various angiogenic factors. Given that hypoxia-inducible factor (HIF) is a critical regulator for angiogenesis, we questioned whether HIF in myeloid cells also plays a role in promoting angiogenesis. To address this question, we generated a unique strain of myeloid-specific knockout mice targeting HIF pathways using human S100A8 as a myeloid-specific promoter. We observed that mutant mice where HIF-1 is transcriptionally activated in myeloid cells (by deletion of the von Hippel-Lindau gene) resulted in erythema, enhanced neovascularization in matrigel plugs, and increased production of vascular endothelial growth factor (VEGF) in the bone marrow, all of which were completely abrogated by either genetic or pharmacological inactivation of HIF-1. We further found that monocytes were the major effector producing VEGF and S100A8 proteins driving neovascularization in matrigel. Moreover, by using a mouse model of hindlimb ischemia we observed significantly improved blood flow in mice intramuscularly injected with HIF-1-activated monocytes. This study therefore demonstrates that HIF-1 activation in myeloid cells promotes angiogenesis through VEGF and S100A8 and that this may become an attractive therapeutic strategy to treat diseases with vascular defects.

    View details for DOI 10.1073/pnas.1320243111

    View details for Web of Science ID 000331396500062

    View details for PubMedID 24497508

    View details for PubMedCentralID PMC3932909

  • The combination of 9p21.3 genotype and biomarker profile improves a peripheral artery disease risk prediction model. Vascular medicine Downing, K. P., Nead, K. T., Kojima, Y., Assimes, T., Maegdefessel, L., Quertermous, T., Cooke, J. P., Leeper, N. J. 2014; 19 (1): 3-8

    Abstract

    Peripheral artery disease (PAD) is a highly morbid condition affecting more than 8 million Americans. Frequently, PAD patients are unrecognized and therefore do not receive appropriate therapies. Therefore, new methods to identify PAD have been pursued, but have thus far had only modest success. Here we describe a new approach combining genomic and metabolic information to enhance the diagnosis of PAD. We measured the genotype of the chromosome 9p21 cardiovascular-risk polymorphism rs10757269 as well as the biomarkers C-reactive protein, cystatin C, β2-microglobulin, and plasma glucose in a study population of 393 patients undergoing coronary angiography. The rs10757269 allele was associated with PAD status (ankle-brachial index < 0.9) independent of biomarkers and traditional cardiovascular risk factors (odds ratio=1.92; 95% confidence interval, 1.29-2.85). Importantly, compared to a previously validated risk factor-based PAD prediction model, the addition of biomarkers and rs10757269 significantly and incrementally improved PAD risk prediction as assessed by the net reclassification index (NRI=33.5%; p=0.001) and integrated discrimination improvement (IDI=0.016; p=0.017). In conclusion, a model including a panel of biomarkers, which includes both genomic information (which is reflective of heritable risk) and metabolic information (which integrates environmental exposures), predicts the presence or absence of PAD better than established risk models, suggesting clinical utility for the diagnosis of PAD.

    View details for DOI 10.1177/1358863X13514791

    View details for PubMedID 24323119

  • Self-reported history of childhood smoking is associated with an increased risk for peripheral arterial disease independent of lifetime smoking burden. PloS one Priest, J. R., Nead, K. T., Wehner, M. R., Cooke, J. P., Leeper, N. J. 2014; 9 (2)

    Abstract

    Atherosclerotic disorders are well known to be associated with obesity, lipid profile, smoking, hypertension and other medical comorbidities, and large cohort studies have explored the childhood correlates to these adult risk factors. However, there has been little investigation into the childhood risk factors for peripheral arterial disease (PAD). We endeavored to better understand the role of smoking in childhood in the risk for PAD in a well described cohort of 1,537 adults at high risk for cardiovascular disease. In a multivariate regression model, we observed an increased risk of PAD among those who reported a history of smoking during childhood (OR = 2.86; 95% CI, 1.99-4.11; P<0.001), which remained statistically significant after controlling for lifetime smoking burden (OR = 1.55; 95% CI, 1.00-2.41; P = 0.049). Our novel observation of disproportionate risk of PAD conferred by a history of childhood smoking may reflect an unrecognized biological mechanism such as a unique susceptibility to vascular injury or an unaccounted for covariate such as secondhand smoke exposure in childhood. This observation suggests further investigation is required into the pathophysiology of smoking in the developing vasculature and the need for detailed clinical data about patterns of childhood smoking and smoke exposure.

    View details for DOI 10.1371/journal.pone.0088972

    View details for PubMedID 24558458

  • Association of lower extremity performance with cardiovascular and all-cause mortality in patients with peripheral artery disease: a systematic review and meta-analysis. Journal of the American Heart Association Morris, D. R., Rodriguez, A. J., Moxon, J. V., Cunningham, M. A., McDermott, M. M., Myers, J., Leeper, N. J., Jones, R. E., Golledge, J. 2014; 3 (4)

    Abstract

    Peripheral artery disease (PAD) is associated with impaired mobility and a high rate of mortality. The aim of this systematic review was to investigate whether reduced lower extremity performance was associated with an increased incidence of cardiovascular and all-cause mortality in people with PAD.A systematic search of the MEDLINE, EMBASE, SCOPUS, Web of Science, and Cochrane Library databases was conducted. Studies assessing the association between measures of lower extremity performance and cardiovascular or all-cause mortality in PAD patients were included. A meta-analysis was conducted combining data from commonly assessed performance tests. The 10 identified studies assessed lower extremity performance by strength tests, treadmill walking performance, 6-minute walk, walking velocity, and walking impairment questionnaire (WIQ). A meta-analysis revealed that shorter maximum walking distance was associated with increased 5-year cardiovascular (unadjusted RR=2.54, 95% CI 1.86 to 3.47, P<10(-5), n=1577, fixed effects) and all-cause mortality (unadjusted RR=2.23 95% CI 1.85 to 2.69, P<10(-5), n=1710, fixed effects). Slower 4-metre walking velocity, a lower WIQ stair-climbing score, and poor hip extension, knee flexion, and plantar flexion strength were also associated with increased mortality. No significant associations were found for hip flexion strength, WIQ distance score, or WIQ speed score with mortality.A number of lower extremity performance measures are prognostic markers for mortality in PAD and may be useful clinical tools for identifying patients at higher risk of death. Further studies are needed to determine whether interventions that improve measures of lower extremity performance reduce mortality.

    View details for DOI 10.1161/JAHA.114.001105

    View details for PubMedID 25122666

  • Self-reported history of childhood smoking is associated with an increased risk for peripheral arterial disease independent of lifetime smoking burden. PloS one Priest, J. R., Nead, K. T., Wehner, M. R., Cooke, J. P., Leeper, N. J. 2014; 9 (2)

    View details for DOI 10.1371/journal.pone.0088972

    View details for PubMedID 24558458

  • Socioeconomic Barriers to the Diagnosis of Peripheral Arterial Disease Chang, P., Nead, K. T., Thakker, R., Cooke, J. P., Olin, J. W., Leeper, N. J. LIPPINCOTT WILLIAMS & WILKINS. 2013
  • Disease-Related Growth Factor and Embryonic Signaling Pathways Modulate an Enhancer of TCF21 Expression at the 6q23.2 Coronary Heart Disease Locus PLOS GENETICS Miller, C. L., Anderson, D. R., Kundu, R. K., Raiesdana, A., Nuernberg, S. T., Diaz, R., Cheng, K., Leeper, N. J., Chen, C., Chang, I., Schadt, E. E., Hsiung, C. A., Assimes, T. L., Quertermous, T. 2013; 9 (7)

    Abstract

    Coronary heart disease (CHD) is the leading cause of mortality in both developed and developing countries worldwide. Genome-wide association studies (GWAS) have now identified 46 independent susceptibility loci for CHD, however, the biological and disease-relevant mechanisms for these associations remain elusive. The large-scale meta-analysis of GWAS recently identified in Caucasians a CHD-associated locus at chromosome 6q23.2, a region containing the transcription factor TCF21 gene. TCF21 (Capsulin/Pod1/Epicardin) is a member of the basic-helix-loop-helix (bHLH) transcription factor family, and regulates cell fate decisions and differentiation in the developing coronary vasculature. Herein, we characterize a cis-regulatory mechanism by which the lead polymorphism rs12190287 disrupts an atypical activator protein 1 (AP-1) element, as demonstrated by allele-specific transcriptional regulation, transcription factor binding, and chromatin organization, leading to altered TCF21 expression. Further, this element is shown to mediate signaling through platelet-derived growth factor receptor beta (PDGFR-β) and Wilms tumor 1 (WT1) pathways. A second disease allele identified in East Asians also appears to disrupt an AP-1-like element. Thus, both disease-related growth factor and embryonic signaling pathways may regulate CHD risk through two independent alleles at TCF21.

    View details for DOI 10.1371/journal.pgen.1003652

    View details for Web of Science ID 000322321100049

    View details for PubMedID 23874238

    View details for PubMedCentralID PMC3715442

  • A hybrid genomic and proteomic biomarker panel accurately predicts peripheral arterial disease status Nead, K. T., Putnam, K., Cooke, J. P., Olin, J. W., Leeper, N. J. SAGE PUBLICATIONS LTD. 2013: 165–65
  • Walking impairment questionnaire improves mortality risk prediction models in a high-risk cohort independent of peripheral arterial disease status. Circulation. Cardiovascular quality and outcomes Nead, K. T., Zhou, M., Caceres, R. D., Olin, J. W., Cooke, J. P., Leeper, N. J. 2013; 6 (3): 255-261

    Abstract

    Background- The Walking Impairment Questionnaire (WIQ) is a subjective measure of patient-reported walking performance developed for peripheral arterial disease. The purpose of this study is to examine whether this simple tool can improve the predictive capacity of established risk models and whether the WIQ can be used in patients without peripheral arterial disease. Methods and Results- At baseline we assessed the walking distance, stair-climbing, and walking speed WIQ category scores among individuals who were undergoing coronary angiography. During a median follow-up of 5.0 years, there were 172 mortalities among 1417 study participants. Adjusted Cox proportional hazards models showed that all 3 WIQ categories independently predicted future all-cause and cardiovascular mortality, including among individuals without peripheral arterial disease (P<0.001). Compared with the cardiovascular risk factors model, we observed significantly increased risk discrimination with a C-index of 0.741 (change in C-index, 0.040; 95% confidence interval, 0.011-0.068) and 0.832 (change in C-index, 0.080; 95% confidence interval, 0.034-0.126) for all-cause and cardiovascular mortality, respectively. Examination of risk reclassification using the net reclassification improvement index showed a 48.4% (P<0.001) improvement for all-cause mortality and a 77.4% (P<0.001) improvement for cardiovascular mortality compared with the cardiovascular risk factors model. Conclusions- All 3 WIQ categories independently predicted future all-cause and cardiovascular mortality. Importantly, we found that this subjective measure of walking ability could be extended to patients without peripheral arterial disease. The addition of the WIQ scores to established cardiovascular risk models significantly improved risk discrimination and reclassification, suggesting broad clinical use for this simple, inexpensive test.

    View details for DOI 10.1161/CIRCOUTCOMES.111.000070

    View details for PubMedID 23633217

  • Usefulness of the Addition of Beta-2-Microglobulin, Cystatin C and C-Reactive Protein to an Established Risk Factors Model to Improve Mortality Risk Prediction in Patients Undergoing Coronary Angiography AMERICAN JOURNAL OF CARDIOLOGY Nead, K. T., Zhou, M. J., Caceres, R. D., Sharp, S. J., Wehner, M. R., Olin, J. W., Cooke, J. P., Leeper, N. J. 2013; 111 (6): 851-856

    Abstract

    Evidence-based therapies are available to reduce the risk for death from cardiovascular disease, yet many patients go untreated. Novel methods are needed to identify those at highest risk for cardiovascular death. In this study, the biomarkers β2-microglobulin, cystatin C, and C-reactive protein were measured at baseline in a cohort of participants who underwent coronary angiography. Adjusted Cox proportional-hazards models were used to determine whether the biomarkers predicted all-cause and cardiovascular mortality. Additionally, improvements in risk reclassification and discrimination were evaluated by calculating the net reclassification improvement, C-index, and integrated discrimination improvement with the addition of the biomarkers to a baseline model of risk factors for cardiovascular disease and death. During a median follow-up period of 5.6 years, there were 78 deaths among 470 participants. All biomarkers independently predicted future all-cause and cardiovascular mortality. A significant improvement in risk reclassification was observed for all-cause (net reclassification improvement 35.8%, p = 0.004) and cardiovascular (net reclassification improvement 61.9%, p = 0.008) mortality compared to the baseline risk factors model. Additionally, there was significantly increased risk discrimination with C-indexes of 0.777 (change in C-index 0.057, 95% confidence interval 0.016 to 0.097) and 0.826 (change in C-index 0.071, 95% confidence interval 0.010 to 0.133) for all-cause and cardiovascular mortality, respectively. Improvements in risk discrimination were further supported using the integrated discrimination improvement index. In conclusion, this study provides evidence that β2-microglobulin, cystatin C, and C-reactive protein predict mortality and improve risk reclassification and discrimination for a high-risk cohort of patients who undergo coronary angiography.

    View details for DOI 10.1016/j.amjcard.2012.11.055

    View details for Web of Science ID 000316537700013

    View details for PubMedID 23290308

    View details for PubMedCentralID PMC3594484

  • AN ALTERNATIVE ANKLE-BRACHIAL INDEX METHOD IDENTIFIES INDIVIDUALS AT HIGH-RISK FOR CARDIOVASCULAR MORTALITY THAT ARE CURRENTLY OVERLOOKED 62nd Annual Scientific Session of the American-College-of-Cardiology Nead, K. T., Cooke, J. P., Leeper, N. J. ELSEVIER SCIENCE INC. 2013: E2124–E2124
  • Exercise capacity is the strongest predictor of mortality in patients with peripheral arterial disease JOURNAL OF VASCULAR SURGERY Leeper, N. J., Myers, J., Zhou, M., Nead, K. T., Syed, A., Kojima, Y., Caceres, R. D., Cooke, J. P. 2013; 57 (3): 728-733

    Abstract

    The objective of this study was to assess the predictive value of clinical and exercise test variables in patients with peripheral arterial disease (PAD).A customized symptom-limited ramp treadmill protocol was used to assess 725 PAD patients referred for exercise testing at the Palo Alto Veterans Hospital between 1997 and 2011. Detailed clinical and exercise test data were collected at baseline, and patients were followed up for a mean of 11.3 ± 6.3 years.During follow-up, there were 364 deaths. Baseline exercise capacity was 7.0 ± 2.6 metabolic equivalents (METs) among survivors and 5.5 ± 2.4 METs in those who died (P < .001). Although several physiologic parameters differed between survivors and nonsurvivors, age-adjusted Cox regression revealed that exercise capacity was the strongest independent predictor of death. Each additional MET achieved was associated with age-adjusted 18% and 20% reductions in all-cause and cardiovascular mortality, respectively (P < .001 for both). This variable surpassed all classical risk factors (including smoking and history of congestive heart failure) and all measured exercise test responses (including symptoms and electrocardiograph abnormalities).Among PAD patients, reduced exercise capacity is the most powerful harbinger of long-term mortality. This factor has predictive power beyond traditional risk factors and confirms the critical importance of fitness in this cohort.

    View details for DOI 10.1016/j.jvs.2012.07.051

    View details for Web of Science ID 000315944400019

    View details for PubMedID 23044259

    View details for PubMedCentralID PMC3543469

  • Disease-related growth factor and embryonic signaling pathways modulate an enhancer of TCF21 expression at the 6q23.2 coronary heart disease locus. PLoS genetics Miller, C. L., Anderson, D. R., Kundu, R. K., Raiesdana, A., Nürnberg, S. T., Diaz, R., Cheng, K., Leeper, N. J., Chen, C., Chang, I., Schadt, E. E., Hsiung, C. A., Assimes, T. L., Quertermous, T. 2013; 9 (7)

    Abstract

    Coronary heart disease (CHD) is the leading cause of mortality in both developed and developing countries worldwide. Genome-wide association studies (GWAS) have now identified 46 independent susceptibility loci for CHD, however, the biological and disease-relevant mechanisms for these associations remain elusive. The large-scale meta-analysis of GWAS recently identified in Caucasians a CHD-associated locus at chromosome 6q23.2, a region containing the transcription factor TCF21 gene. TCF21 (Capsulin/Pod1/Epicardin) is a member of the basic-helix-loop-helix (bHLH) transcription factor family, and regulates cell fate decisions and differentiation in the developing coronary vasculature. Herein, we characterize a cis-regulatory mechanism by which the lead polymorphism rs12190287 disrupts an atypical activator protein 1 (AP-1) element, as demonstrated by allele-specific transcriptional regulation, transcription factor binding, and chromatin organization, leading to altered TCF21 expression. Further, this element is shown to mediate signaling through platelet-derived growth factor receptor beta (PDGFR-β) and Wilms tumor 1 (WT1) pathways. A second disease allele identified in East Asians also appears to disrupt an AP-1-like element. Thus, both disease-related growth factor and embryonic signaling pathways may regulate CHD risk through two independent alleles at TCF21.

    View details for DOI 10.1371/journal.pgen.1003652

    View details for PubMedID 23874238

    View details for PubMedCentralID PMC3715442

  • Practice-based evidence: profiling the safety of cilostazol by text-mining of clinical notes. PloS one Leeper, N. J., Bauer-Mehren, A., Iyer, S. V., LePendu, P., Olson, C., Shah, N. H. 2013; 8 (5)

    View details for DOI 10.1371/journal.pone.0063499

    View details for PubMedID 23717437

  • Network analysis of unstructured EHR data for clinical research. AMIA Summits on Translational Science proceedings AMIA Summit on Translational Science Bauer-Mehren, A., LePendu, P., Iyer, S. V., Harpaz, R., Leeper, N. J., Shah, N. H. 2013; 2013: 14-18

    Abstract

    In biomedical research, network analysis provides a conceptual framework for interpreting data from high-throughput experiments. For example, protein-protein interaction networks have been successfully used to identify candidate disease genes. Recently, advances in clinical text processing and the increasing availability of clinical data have enabled analogous analyses on data from electronic medical records. We constructed networks of diseases, drugs, medical devices and procedures using concepts recognized in clinical notes from the Stanford clinical data warehouse. We demonstrate the use of the resulting networks for clinical research informatics in two ways-cohort construction and outcomes analysis-by examining the safety of cilostazol in peripheral artery disease patients as a use case. We show that the network-based approaches can be used for constructing patient cohorts as well as for analyzing differences in outcomes by comparing with standard methods, and discuss the advantages offered by network-based approaches.

    View details for PubMedID 24303229

  • Practice-based evidence: profiling the safety of cilostazol by text-mining of clinical notes. PloS one Leeper, N. J., Bauer-Mehren, A., Iyer, S. V., LePendu, P., Olson, C., Shah, N. H. 2013; 8 (5)

    Abstract

    Peripheral arterial disease (PAD) is a growing problem with few available therapies. Cilostazol is the only FDA-approved medication with a class I indication for intermittent claudication, but carries a black box warning due to concerns for increased cardiovascular mortality. To assess the validity of this black box warning, we employed a novel text-analytics pipeline to quantify the adverse events associated with Cilostazol use in a clinical setting, including patients with congestive heart failure (CHF).We analyzed the electronic medical records of 1.8 million subjects from the Stanford clinical data warehouse spanning 18 years using a novel text-mining/statistical analytics pipeline. We identified 232 PAD patients taking Cilostazol and created a control group of 1,160 PAD patients not taking this drug using 1∶5 propensity-score matching. Over a mean follow up of 4.2 years, we observed no association between Cilostazol use and any major adverse cardiovascular event including stroke (OR = 1.13, CI [0.82, 1.55]), myocardial infarction (OR = 1.00, CI [0.71, 1.39]), or death (OR = 0.86, CI [0.63, 1.18]). Cilostazol was not associated with an increase in any arrhythmic complication. We also identified a subset of CHF patients who were prescribed Cilostazol despite its black box warning, and found that it did not increase mortality in this high-risk group of patients.This proof of principle study shows the potential of text-analytics to mine clinical data warehouses to uncover 'natural experiments' such as the use of Cilostazol in CHF patients. We envision this method will have broad applications for examining difficult to test clinical hypotheses and to aid in post-marketing drug safety surveillance. Moreover, our observations argue for a prospective study to examine the validity of a drug safety warning that may be unnecessarily limiting the use of an efficacious therapy.

    View details for DOI 10.1371/journal.pone.0063499

    View details for PubMedID 23717437

    View details for PubMedCentralID PMC3662653

  • Loss of CDKN2B Promotes p53-Dependent Smooth Muscle Cell Apoptosis and Aneurysm Formation ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Leeper, N. J., Raiesdana, A., Kojima, Y., Kundu, R. K., Cheng, H., Maegdefessel, L., Toh, R., Ahn, G., Ali, Z. A., Anderson, D. R., Miller, C. L., Roberts, S. C., Spin, J. M., de Almeida, P. E., Wu, J. C., Xu, B., Cheng, K., Quertermous, M., Kundu, S., Kortekaas, K. E., Berzin, E., Downing, K. P., Dalman, R. L., Tsao, P. S., Schadt, E. E., Owens, G. K., Quertermous, T. 2013; 33 (1): E1-?

    Abstract

    Genomewide association studies have implicated allelic variation at 9p21.3 in multiple forms of vascular disease, including atherosclerotic coronary heart disease and abdominal aortic aneurysm. As for other genes at 9p21.3, human expression quantitative trait locus studies have associated expression of the tumor suppressor gene CDKN2B with the risk haplotype, but its potential role in vascular pathobiology remains unclear.Here we used vascular injury models and found that Cdkn2b knockout mice displayed the expected increase in proliferation after injury, but developed reduced neointimal lesions and larger aortic aneurysms. In situ and in vitro studies suggested that these effects were attributable to increased smooth muscle cell apoptosis. Adoptive bone marrow transplant studies confirmed that the observed effects of Cdkn2b were mediated through intrinsic vascular cells and were not dependent on bone marrow-derived inflammatory cells. Mechanistic studies suggested that the observed increase in apoptosis was attributable to a reduction in MDM2 and an increase in p53 signaling, possibly due in part to compensation by other genes at the 9p21.3 locus. Dual inhibition of both Cdkn2b and p53 led to a reversal of the vascular phenotype in each model.These results suggest that reduced CDKN2B expression and increased smooth muscle cell apoptosis may be one mechanism underlying the 9p21.3 association with aneurysmal disease.

    View details for DOI 10.1161/ATVBAHA.112.300399

    View details for Web of Science ID 000312392500001

    View details for PubMedID 23162013

    View details for PubMedCentralID PMC3569043

  • The Walking Impairment Questionnaire Predicts Total and Cardiovascular Mortality Independent of Peripheral Artery Disease Status Nead, K. T., Zhou, M., Diaz-Caceres, R., Roberts, S. E., Lee, W. L., Phan, N. H., Roberts, S. C., Garcia, K., Chhor, B., Luong, D. N., Cooke, J. P., Leeper, N. J. LIPPINCOTT WILLIAMS & WILKINS. 2012
  • Genetics of Peripheral Artery Disease CIRCULATION Leeper, N. J., Kullo, I. J., Cooke, J. P. 2012; 125 (25): 3220-3228
  • Exercise capacity is the strongest predictor of mortality in patients with peripheral arterial disease Zhou, M., Leeper, N. J., Nead, K. T., Syed, A., Abella, J., Kojima, Y., Panchal, S. N., Cooke, J. P., Myers, J. SAGE PUBLICATIONS LTD. 2012: 204–5
  • The Effect of Angiotensin-Converting Enzyme Inhibitors and Statins on the Progression of Aortic Sclerosis and Mortality JOURNAL OF HEART VALVE DISEASE Ardehali, R., Leeper, N. J., Wilson, A. M., Heidenreich, P. A. 2012; 21 (3): 337-343

    Abstract

    Although aortic sclerosis has been associated with an increase in adverse cardiovascular outcomes, no proven therapy has been shown to slow its progression to overt aortic stenosis (AS). Thus, the hypothesis was assessed that treatment with angiotensin-converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers (ARBs) or statins may be associated with an improvement in the clinical outcome of these patients.A total of 4,105 patients with evidence of aortic sclerosis seen on transthoracic echocardiography (defined as thickening or calcification with a mean valve gradient < or = 15 mmHg) was identified. Patients with a sclerotic valve who were treated with ACE-Is/ARBs or statins were followed for a mean period of 1,078 +/- 615 days. After adjustment for the propensity to receive ACE-Is/ARBs or statins, mortality, hemodynamic progression to AS, hospitalization for ischemic heart disease (IHD), and congestive heart failure (CHF) were assessed and related to the medical treatment.At baseline, patients with aortic sclerosis who were treated with an ACE-I/ARB or a statin suffered significantly more from comorbidities such as IHD, CHF, hypertension, diabetes, and peripheral arterial disease, when compared to subjects with sclerotic valves not treated with these drugs. After adjustment for confounding factors, treatment with statins was associated with a significant reduction in mortality (odds ratio [OR] 0.73, 95% CI 0.56-0.98, p = 0.001), admission for IHD (OR 0.81, 95% CI 0.66-0.99, p = 0.03), admission for CHF (OR 0.68, 95% CI 0.55-0.85, p = 0.01) and progression to AS (OR 0.64, 95% CI 0.42-0.97, p = 0.03). While ACE-I treatment resulted in a significant reduction in admission for IHD (OR 0.80, 95% CI 0.65-0.98, p = 0.03) and CHF (OR 0.76, 95% CI 0.62-0.94, p = 0.01), the beneficial trend towards reduced mortality and delayed progression to AS was not significant.Treatment of this patient population with statins led to a significant reduction in mortality and also slowed the progression to AS--an effect that was not statistically significant with ACE-I treatment.

    View details for Web of Science ID 000306675500011

    View details for PubMedID 22808835

  • Inhibition of microRNA-29b reduces murine abdominal aortic aneurysm development JOURNAL OF CLINICAL INVESTIGATION Maegdefessel, L., Azuma, J., Toh, R., Merk, D. R., Deng, A., Chin, J. T., Raaz, U., Schoelmerich, A. M., Raiesdana, A., Leeper, N. J., McConnell, M. V., Dalman, R. L., Spin, J. M., Tsao, P. S. 2012; 122 (2): 497-506

    Abstract

    MicroRNAs (miRs) regulate gene expression at the posttranscriptional level and play crucial roles in vascular integrity. As such, they may have a role in modifying abdominal aortic aneurysm (AAA) expansion, the pathophysiological mechanisms of which remain incompletely explored. Here, we investigate the role of miRs in 2 murine models of experimental AAA: the porcine pancreatic elastase (PPE) infusion model in C57BL/6 mice and the AngII infusion model in Apoe-/- mice. AAA development was accompanied by decreased aortic expression of miR-29b, along with increased expression of known miR-29b targets, Col1a1, Col3a1, Col5a1, and Eln, in both models. In vivo administration of locked nucleic acid anti-miR-29b greatly increased collagen expression, leading to an early fibrotic response in the abdominal aortic wall and resulting in a significant reduction in AAA progression over time in both models. In contrast, overexpression of miR-29b using a lentiviral vector led to augmented AAA expansion and significant increase of aortic rupture rate. Cell culture studies identified aortic fibroblasts as the likely vascular cell type mediating the profibrotic effects of miR-29b modulation. A similar pattern of reduced miR-29b expression and increased target gene expression was observed in human AAA tissue samples compared with that in organ donor controls. These data suggest that therapeutic manipulation of miR-29b and its target genes holds promise for limiting AAA disease progression and protecting from rupture.

    View details for DOI 10.1172/JCI61598

    View details for PubMedID 22269326

  • Network Analysis Identifies the Orphan Receptor Tyrosine Kinase Ros1 as a Determinant of Glutathione Peroxidase-1 Mediated Vascular Remodeling Scientific Sessions of the American-Heart-Association/Resuscitation Science Symposium Ali, Z. A., Perez, V. D., Raiesdana, A., Leeper, N. J., Pan, S., Qu, X., Ali, A., Haghighat, R., Kato, K., Channon, K. M., Rabinovitch, M., Quertermous, T., Ashley, E. A. LIPPINCOTT WILLIAMS & WILKINS. 2011
  • Microrna-21 Regulates Expansion of Abdominal Aortic Aneurysms Through the PTEN/PI3K/AKT Pathway Scientific Sessions of the American-Heart-Association/Resuscitation Science Symposium Maegdefessel, L., Azuma, J., Deng, A., Toh, R. M., Merk, D. R., Raiesdana, A., Leeper, N. J., Spin, J. M., Tsao, P. S. LIPPINCOTT WILLIAMS & WILKINS. 2011
  • Two Decades of Progress in Vascular Medicine AMERICAN JOURNAL OF MEDICINE Leeper, N. J., Lee, J. T., Cooke, J. P. 2011; 124 (9): 791-792

    View details for DOI 10.1016/j.amjmed.2011.03.017

    View details for PubMedID 21683936

  • MicroRNA and Mechanisms of Impaired Angiogenesis in Diabetes Mellitus CIRCULATION Leeper, N. J., Cooke, J. P. 2011; 123 (3): 236-238
  • CDKN2B Regulates Cell Fate Decisions in Human Vascular Smooth Muscle Cells Leeper, N. J., Raiesdana, A., Cheng, H., Kundu, R. K., Kojima, Y., Cheng, K., Schadt, E., Quertermous, T. LIPPINCOTT WILLIAMS & WILKINS. 2010
  • The Role of CDKN2B in Vascular Disease Cheng, H. G., Leeper, N. J., Raisedana, A., Kundu, R., Kojima, Y., Quertermous, T. LIPPINCOTT WILLIAMS & WILKINS. 2010
  • Microarray Analysis Identifies miRNA-26a as a Regulator of Vascular Smooth Muscle Cell Phenotypic Modulation Scientific Sessions on Arteriosclerosis, Thrombosis and Vascular Biology Leeper, N. J., Raiesdana, A., Kojima, Y., Chun, H. J., Azuma, J., Kundu, R. K., Quertermous, T., Tsao, P. S., Spin, J. M. LIPPINCOTT WILLIAMS & WILKINS. 2010: E244–E244
  • Upregulation of the apelin-APJ pathway promotes neointima formation in the carotid ligation model in mouse CARDIOVASCULAR RESEARCH Kojima, Y., Kundu, R. K., Cox, C. M., Leeper, N. J., Anderson, J. A., Chun, H. J., Ali, Z. A., Ashley, E. A., Krieg, P. A., Quertermous, T. 2010; 87 (1): 156-165

    Abstract

    To investigate apelin-APJ (angiotensin receptor-like 1) signalling in vascular remodelling, we have examined the pathophysiological response to carotid ligation in apelin knockout mice.Apelin null animals compared with wild-type mice had significantly decreased neointimal lesion area (1.17 +/- 0.17 vs. 3.33 +/- 1.04 x 10(4) microm(2), P < 0.05) and intima/media ratio (0.81 +/- 0.23 vs. 1.49 +/- 0.44, P < 0.05), averaged over four sites 0.5-2 mm from the ligation. Exogenous apelin infusion rescued the apelin-KO phenotype, promoting neointima formation in the null animals. Apelin null animals showed decreased smooth muscle positive area in the neointima (82.3 +/- 2.4 vs. 63.9 +/- 8.4, P < 0.05), and a smaller percentage BrdU positive cells in the neointima and media (11.06 +/- 1.00 vs. 6.53 +/- 0.86, P < 0.05). Apelin mRNA expression increased initially (5.2-fold, P < 0.01) followed by increased apelin receptor expression (10.1-fold, P < 0.05) in the ligated artery. Cytochemistry studies localized apelin expression to luminal endothelial cells and apelin receptor upregulation to smooth muscle cells (SMC) in the media and neointima. In vitro experiments with cultured rat aortic SMC revealed that apelin stimulation increased migration. In contrast to the increased expression of apelin and apelin receptor in carotid remodelling, expression was not upregulated in the apoE high fat model, and correlated with the known disease-inhibitory effect in this model.These data suggest that increased apelin receptor expression by SMC provides a paracrine pathway in injured vessels that allows endothelial-derived apelin to stimulate their division and migration into the neointima.

    View details for DOI 10.1093/cvr/cvq052

    View details for PubMedID 20176814

  • Apelin Modulates Adipocyte and Inflammatory Cell Processes to Inhibit Atherosclerosis Kojima, Y., Kundu, R., Leeper, N. J., Chun, H. J., Quertermous, T. LIPPINCOTT WILLIAMS & WILKINS. 2009: S1064
  • Endogenous regulation of cardiovascular function by apelin-APJ AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY Charo, D. N., Ho, M., Fajardo, G., Kawana, M., Kundu, R. K., Sheikh, A. Y., Finsterbach, T. P., Leeper, N. J., Ernst, K. V., Chen, M. M., Ho, Y. D., Chun, H. J., Bernstein, D., Ashley, E. A., Quertermous, T. 2009; 297 (5): H1904-H1913

    Abstract

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

    View details for DOI 10.1152/ajpheart.00686.2009

    View details for Web of Science ID 000271143400045

    View details for PubMedID 19767528

    View details for PubMedCentralID PMC2781363

  • Apelin Regulates Vascular Remodeling In The Mouse Carotid Artery Ligation Model Kojima, Y., Kundu, R., Leeper, N. J., Anderson, J., Quertermous, T. LIPPINCOTT WILLIAMS & WILKINS. 2008: S574
  • Apelin Prevents Aortic Aneurysm Formation by Inhibiting Macrophage Inflammation and Infiltration Leeper, N. J., Tedesco, M. M., Kojima, Y., Schultz, G., Ho, M. Y., Kundu, R. K., Anderson, J. P., Tsao, P. S., Dolman, R. L., Quedermous, T. LIPPINCOTT WILLIAMS & WILKINS. 2008: S451
  • Atherosclerosis Development is Increased in Apelin/Apoe Double Knockout Mice Kojima, Y., Kundu, R., Leeper, N. J., Quortermous, T. LIPPINCOTT WILLIAMS & WILKINS. 2008: S481
  • Apelin signaling antagonizes Ang II effects in mouse models of atherosclerosis JOURNAL OF CLINICAL INVESTIGATION Chun, H. J., Ali, Z. A., Kojima, Y., Kundu, R. K., Sheikh, A. Y., Agrawal, R., Zheng, L., Leeper, N. J., Pearl, N. E., Patterson, A. J., Anderson, J. P., Tsao, P. S., Lenardo, M. J., Ashley, E. A., Quertermous, T. 2008; 118 (10): 3343-3354

    Abstract

    Apelin and its cognate G protein-coupled receptor APJ constitute a signaling pathway with a positive inotropic effect on cardiac function and a vasodepressor function in the systemic circulation. The apelin-APJ pathway appears to have opposing physiological roles to the renin-angiotensin system. Here we investigated whether the apelin-APJ pathway can directly antagonize vascular disease-related Ang II actions. In ApoE-KO mice, exogenous Ang II induced atherosclerosis and abdominal aortic aneurysm formation; we found that coinfusion of apelin abrogated these effects. Similarly, apelin treatment rescued Ang II-mediated increases in neointimal formation and vascular remodeling in a vein graft model. NO has previously been implicated in the vasodepressor function of apelin; we found that apelin treatment increased NO bioavailability in ApoE-KO mice. Furthermore, infusion of an NO synthase inhibitor blocked the apelin-mediated decrease in atherosclerosis and aneurysm formation. In rat primary aortic smooth muscle cells, apelin inhibited Ang II-mediated transcriptional regulation of multiple targets as measured by reporter assays. In addition, we demonstrated by coimmunoprecipitation and fluorescence resonance energy transfer analysis that the Ang II and apelin receptors interacted physically. Taken together, these findings indicate that apelin signaling can block Ang II actions in vascular disease by increasing NO production and inhibiting Ang II cellular signaling.

    View details for DOI 10.1172/JCI34871

    View details for PubMedID 18769630

  • Response to letter regarding article, "Statin use in patients with extremely low low-density lipoprotein levels is associated with improved survival" CIRCULATION Leeper, N. J., Ardehali, R., DeGoma, E. M., Heidenreich, P. A. 2008; 117 (9): E175-E175
  • Clinical significance of high-density lipoprotein cholesterol in patients with low low-density lipoprotein cholesterol JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY deGoma, E. M., Leeper, N. J., Heidenreich, P. A. 2008; 51 (1): 49-55

    Abstract

    We sought to evaluate the significance of high-density lipoprotein cholesterol (HDL-C) in the context of low low-density lipoprotein cholesterol (LDL-C).Earlier studies support an inverse correlation between circulating HDL-C and coronary risk in patients with normal or elevated LDL-C.This study involved 4,188 patients attending the Palo Alto Veterans Administration Medical Center or affiliated clinics with LDL-C levels below 60 mg/dl. Outcomes were examined 1 year after the index LDL-C date. The combined primary end point was myocardial injury or hospitalization from ischemic heart disease. The secondary end point was all-cause mortality.Mean HDL-C levels (mg/dl) by quartile (Q) were: Q1 28 mg/dl, Q2 36 mg/dl, Q3 43 mg/dl, and Q4 63 mg/dl. The rate of myocardial injury or hospitalization for ischemic heart disease showed an inverse relationship to HDL-C (adjusted odds ratios: Q1 1.59 [95% confidence interval (CI) 1.16 to 2.19], Q2 1.39 [95% CI 1.01 to 1.92], Q3 1.33 [95% CI 0.96 to 1.84], and Q4 reference) that persisted regardless of statin use or recent myocardial injury. Analyzing HDL-C as a continuous variable revealed a 10% [95% CI 3% to 17%] increase in the combined end point of myocardial injury or hospitalization for ischemic heart disease for every 10-mg/dl decrease in HDL-C. The unadjusted and adjusted incidence of all-cause mortality demonstrated a U-shaped relationship to HDL-C (adjusted odds ratios: Q1 1.13 [95% CI 0.79 to 1.62], Q2 0.97 [95% CI 0.67 to 1.40], Q3 0.74 [95% CI 0.50 to 1.09], and Q4 reference).The inverse relationship between HDL-C and coronary risk persists even among patients with LDL-C below 60 mg/dl, although a U-shaped relationship is observed between HDL-C and all-cause mortality.

    View details for DOI 10.1016/j.jacc.2007.07.086

    View details for Web of Science ID 000252510300008

    View details for PubMedID 18174036

  • Prognostic value of heart rate increase at onset of exercise testing CIRCULATION Leeper, N. J., Dewey, F. E., Ashley, E. A., Sandri, M., Tan, S. Y., Hadley, D., Myers, J., Froelicher, V. 2007; 115 (4): 468-474

    Abstract

    The initial response of heart rate to dynamic exercise has been proposed as having prognostic value in limited studies that have used modalities other than the treadmill. Our aim was to evaluate the prognostic value of early heart rate parameters in patients referred for routine clinical treadmill testing.The heart rate rise at the onset of exercise was measured in 1959 patients referred for clinical treadmill testing at the Palo Alto (Calif) Veterans Affairs Medical Center from 1997 to 2004. Multivariable Cox survival analysis was performed for 197 all-cause and 74 cardiovascular deaths that accrued during a mean follow-up of 5.4+/-2.1 years. Decreased heart rate changes at all initial relative exercise workloads were associated with significantly increased all-cause mortality. The heart rate rise at one-third total exercise capacity, however, was the only early heart rate variable that significantly predicted both all-cause and cardiovascular risk after adjustment for confounders. Failing to reach 1 SD in the heart rate rise at one-third total exercise capacity was associated with a 28% increased all-cause mortality rate (hazard ratio, 0.72; 95% CI, 0.61 to 0.85; P<0.001) and a 35% cardiovascular mortality rate (hazard ratio, 0.65; 95% CI, 0.49 to 0.86; P=0.003). Of all heart rate measurements considered (initial and recovery), the heart rate increase at peak exercise was the most powerful predictor of cardiovascular prognosis after adjustment for potential confounders. The Duke treadmill score, however, was superior to all heart rate measurements in the prediction of cardiovascular mortality.In the present study population, a rapid initial heart rate rise was associated with improved survival, but the heart rate increase at peak exercise and other conventional measurements such as exercise capacity and the Duke treadmill score were more powerful predictors of prognosis.

    View details for DOI 10.1161/CIRCULATIONAHA.106.666388

    View details for PubMedID 17242274

  • Clinical dilemmas in treating left ventricular thrombus. International journal of cardiology Leeper, N. J., Gupta, A., Schnittger, I., Wu, J. C. 2007; 114 (3): e118-9

    View details for PubMedID 17049652

  • Clinical significance of HDL-c levels among patients with LDL-c less than 60 mg/dl deGoma, E., Leeper, N. J., Heidenreich, P. A. LIPPINCOTT WILLIAMS & WILKINS. 2006: 899
  • Statin use in patients with extremely low LDL levels is associated with improved survival Leeper, N. J., Ardehali, R., DeGoma, E. M., Heidenreich, P. A. LIPPINCOTT WILLIAMS & WILKINS. 2006: 827–28
  • Right coronary cameral fistula resulting from surgery of double chamber right ventricle. Journal of the American Society of Echocardiography Leeper, N. J., Gupta, A., Murphy, D. J., Wu, J. C. 2006; 19 (9): 1191 e9-11

    View details for PubMedID 16950481

  • The effect of preoperative statin therapy on cardiovascular outcomes in patients undergoing infrainguinal vascular surgery INTERNATIONAL JOURNAL OF CARDIOLOGY Ward, R. P., Leeper, N. J., Kirkpatrick, J. N., Lang, R. M., Sorrentino, M. J., Williams, K. A. 2005; 104 (3): 264-268

    Abstract

    Patients undergoing vascular surgery are at increased risk for perioperative cardiovascular (CV) complications. Our goal was to determine the effect of preoperative statin therapy on perioperative cardiac and vascular outcomes, and long-term survival in patients undergoing infrainguinal vascular bypass surgery.We retrospectively reviewed consecutive infrainguinal vascular bypass surgeries on 446 patients performed between 1995-2001 at the University of Chicago Medical Center. Information was collected on preoperative statin and beta-blocker use, baseline characteristics, perioperative cardiac and major vascular complications, and length of stay (LOS). Long-term survival was assessed using the Social Security Death Index (SSDI).Thirty day perioperative complications included all-cause mortality (2.5%), CV mortality (1.8%), myocardial infarction (MI) (4.7%), stroke (1.1%), and major peripheral vascular complications (12.8%), and the composite of cardiac and vascular complications [combined CV complications] (17.9%). Statin therapy was associated with fewer combined CV complications (6.9% vs 20.1%, p=0.008), and a shorter LOS (6.4 vs 9.7 days, p=0.007). On multivariate logistic regression analysis, adjusting for significant baseline characteristics including beta-blocker use, statin therapy was independently associated fewer combined CV complications (odds ratio (OR) 0.36, 95% confidence interval (CI) 0.14-0.93, p=0.035) and a shorter LOS (OR 1.49, 95% CI 1.14-1.95, p=0.003). In a mean follow up period of 5.5 years, 215 deaths (48%) occurred. Statin therapy was independently associated with improved long-term survival (OR 0.52, 95% CI 0.32-0.84, p<0.004), after adjusting for significant baseline characteristics.Preoperative statin therapy is associated with fewer combined perioperative cardiac and major vascular complications, a shorter length of stay, and improved long-term survival in patients undergoing infrainguinal vascular bypass surgery.

    View details for DOI 10.1016/j.ijcard.2004.10.030

    View details for Web of Science ID 000232752700004

    View details for PubMedID 16186054

  • One surprise after another NEW ENGLAND JOURNAL OF MEDICINE Leeper, N. J., Wener, L. S., Dhaliwal, G., Saint, S., Wachter, R. M. 2005; 352 (14): 1474-1479
  • Interleukin-6 causes endothelial barrier dysfunction via the protein kinase C pathway 35th Annual Meeting of the Association-for-Academic-Surgery Desai, T. R., Leeper, N. J., Hynes, K. L., Gewertz, B. L. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2002: 118–23

    Abstract

    Elevated levels of interleukin-6 (IL-6) have been identified in a variety of systemic inflammatory states that are associated with endothelial barrier dysfunction, but the specific effect of IL-6 on endothelial permeability and the mechanism of action have not been fully examined. The current study evaluated the effect of IL-6 on endothelial permeability and on the distribution of the tight junctional protein ZO-1 and cytoskeletal actin. We also assessed the role of protein kinase C (PKC) in this process.Confluent monolayers of human umbilical vein endothelial cells (n = 6) were exposed to IL-6 (50-500 ng/ml) in the presence or absence of the PKC inhibitor Gö6976 (0.1 microM). Transendothelial electrical resistance (TEER) was measured at the onset of exposure and at 6-h intervals and compared with that of control cells using ANOVA with a Bonferroni multiple comparison test. Additional monolayers were exposed to IL-6, stained for ZO-1 and F-actin, and evaluated via fluorescence microscopy.Interleukin-6 increased endothelial permeability as measured by TEER in a dose- and time-dependent manner. In the presence of PKC inhibitor, the IL-6-mediated increase in permeability was attenuated (18-h TEER 73% of control with IL-6 exposure vs 95% of control with IL-6 + Gö6976 inhibitor, P < 0.01). Microscopy revealed that permeability changes were accompanied by a redistribution of the tight junctional protein ZO-1 and cytoskeletal actin, increased cell contraction, and disorganization of the intercellular borders. Conclusions. The inflammatory cytokine IL-6 is an important mediator of increased endothelial permeability via alterations in the ultrastructural distribution of tight junctions and morphologic changes in cell shape. PKC is a critical intracellular messenger in these IL-6-mediated changes. A better understanding of this mechanism should allow the determination of rational treatment strategies for endothelial barrier dysfunction which occurs in inflammatory states.

    View details for DOI 10.1006/jsre.2002.6415

    View details for Web of Science ID 000176074300008

    View details for PubMedID 12020130

  • Gender does not influence outcomes after iliac angioplasty 26th Annual Meeting of the Peripheral-Vascular-Surgery-Society Orr, J. D., Leeper, N. J., Funaki, B., Leef, J., Gewertz, B. L., Desai, T. R. ELSEVIER SCIENCE INC. 2002: 55–60

    Abstract

    The current study was undertaken to evaluate the potential influence of gender on iliac angioplasty outcomes. All iliac angioplasty procedures performed at a tertiary care center from 1994 to 1999 were reviewed. One hundred four angioplasties with or without stenting were performed in 44 women (56 limbs) and 40 men (48 limbs). Age and atherosclerotic risk factors were similar in men and women. Iliac angioplasty was performed for limb salvage in 41% of patients (39% female vs. 44% male; p = 0.65). There were no differences in degree of stenosis, lesion length, or initial angioplasty site. Female iliac arteries were more likely to be occluded (21% vs. 6%; p = 0.03); mean iliac artery luminal diameter was smaller in women than in men (6.5 +/- 0.5 mm vs. 8.2 +/- 0.6 mm; p < 0.001). After a median follow-up of 13 months, there were no significant differences in 2-year primary patency, endovascular primary-assisted patency, or limb salvage rates between women and men. Despite having smaller iliac arteries and a higher incidence of arterial occlusion before treatment, women had outcomes similar to those of men after iliac angioplasty. The current results support the initial use of angioplasty to treat common and external iliac artery occlusive disease in both women and men.

    View details for DOI 10.1007/s10016-001-0131-7

    View details for Web of Science ID 000174307700010

    View details for PubMedID 11904805

  • Regulated expression of a unique lipase in endothelial cells suggests a local role in disease-associated lipid metabolism in the blood vessel wall Hirata, K., Dichek, H. L., Choi, S. Y., Leeper, N. J., Cooper, A. D., Quertermous, T. LIPPINCOTT WILLIAMS & WILKINS. 1999: 610–10
  • Tetracycline-regulatable expression vectors tightly regulate in vitro gene expression of secreted proteins GENE Sturtz, F. G., Cioffi, L., Wittmer, S., Sonk, M. J., Shafer, A., Li, Y. S., Leeper, N. J., Smith-Gbur, J., Shulok, J., Platika, D. 1998; 221 (2): 279-285

    Abstract

    The regulation of gene expression by the tetracycline system has attracted a high level of interest in the recent past. However, expression of secreted proteins has not been evaluated precisely. In this study, we constructed two versions of a one-plasmid system containing the elements necessary for the regulation of gene expression. The regulatable elements and the selectable marker (Neor) were set up in two different configurations, pTRIN31 and pTRIN76. With these two regulatable versions, the levels of protein expression after transfection into the NIH/3T3 cell line were measured by insertion of three different genes encoding the secreted proteins (hGH, ApoE3, hGM-CSF). The maximum levels of gene expression obtained with the pTRIN76-derived plasmids were 100ng/24h/106 cells for hGH, 427ng/24h/106 cells for ApoE3 and 108ng/24h/106 cells for hGM-CSF. For the pTRIN31-derived plasmids the maximum levels were 2.7ng/24h/106 cells for hGH and 47ng/24h/106 for ApoE3. Both plasmids give rise to an expression of the transfected gene that can be tightly regulated by three different molecules: tetracycline, minocycline and doxycycline. The levels of the secreted proteins are below the detectable level when the reporter genes are repressed. This repression is reversible within 48h after the regulator has been removed from the medium.

    View details for Web of Science ID 000077027300013

    View details for PubMedID 9795241