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Abstract
PURPOSE OF REVIEW African Americans are over-burdened with hypertension resulting in excess morbidity and mortality. We highlight the health impact of hypertension in this population, review important observations regarding disease pathogenesis, and outline evidence-based treatment, current treatment guidelines, and management approaches. RECENT FINDINGS Hypertension accounts for 50% of the racial differences in mortality between Blacks and Whites in the USA. Genome-wide association studies have not clearly identified distinct genetic causes for the excess burden in this population as yet. Pathophysiology is complex likely involving interaction of genetic, biological, and social factors prevalent among African Americans. Non-pharmacologic and pharmacologic therapy is required and specific treatment guidelines for this population are varied. Combination therapy is most often necessary and single-pill formulations are most successful in achieving BP targets. Racial health disparities related to hypertension in African Americans are a serious public health concern that warrants greater attention. Multi-disciplinary research to understand the inter-relationship between biological and social factors is needed to guide successful treatments. Comprehensive care strategies are required to successfully address and eliminate the hypertension burden.
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Affiliation(s)
- Nomsa Musemwa
- Department of Medicine, Division of Nephrology, Hypertension and Kidney Transplantation, Temple University School of Medicine, Kresge West, Suite 100, 3440 North Broad Street, Philadelphia, PA, 19140, USA
| | - Crystal A Gadegbeku
- Department of Medicine, Division of Nephrology, Hypertension and Kidney Transplantation, Temple University School of Medicine, Kresge West, Suite 100, 3440 North Broad Street, Philadelphia, PA, 19140, USA.
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Chen TK, Estrella MM. APOL1 risk variants and death among African American hemodialysis patients: survival of the fittest? Kidney Int 2017; 90:249-252. [PMID: 27418089 DOI: 10.1016/j.kint.2016.03.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 03/24/2016] [Indexed: 11/16/2022]
Abstract
Recent studies have focused on associations of the APOL1 risk variants with outcomes beyond kidney disease, including cardiovascular disease and mortality. Ma and colleagues now expand on this growing but contradicting body of work. Their analysis of a prevalent cohort of African American hemodialysis patients shows that the risk variants are associated with a survival benefit among nondiabetics. Whether this simply reflects a healthier status at hemodialysis initiation among those carrying 2 risk variants or whether these variants truly confer a survival advantage is unclear.
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Affiliation(s)
- Teresa K Chen
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Michelle M Estrella
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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Chen TK, Estrella MM, Vittinghoff E, Lin F, Gutierrez OM, Kramer H, Lewis CE, Kopp JB, Allen NB, Winkler CA, Bibbins-Domingo KB, Peralta CA. APOL1 genetic variants are not associated with longitudinal blood pressure in young black adults. Kidney Int 2017; 92:964-971. [PMID: 28545715 PMCID: PMC5610603 DOI: 10.1016/j.kint.2017.03.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/08/2017] [Accepted: 03/16/2017] [Indexed: 01/13/2023]
Abstract
Whether APOL1 polymorphisms contribute to the excess risk of hypertension among blacks is unknown. To assess this we evaluated whether self-reported race and, in blacks, APOL1 risk variants (high-risk [2 risk alleles] versus low-risk [0-1 risk allele]) were associated with longitudinal blood pressure. Blood pressure trajectories were determined using linear mixed-effects (slope) and latent class models (5 distinct groups) during 25 years of follow-up in the Coronary Artery Risk Development in Young Adults Study. Associations of race and APOL1 genotypes with blood pressure change, separately, using linear mixed-effects and multinomial logistic regression models, adjusting for demographic, socioeconomic, and traditional hypertension risk factors, anti-hypertensive medication use, and kidney function were evaluated. Among 1700 whites and 1330 blacks (13% APOL1 high-risk, mean age 25 years; 46% male) mean mid-, ([systolic + diastolic blood pressure]/2), systolic, and diastolic blood pressures were 89, 110, and 69 mm Hg, respectively. One percent of participants used anti-hypertensive medications at baseline. Compared to whites, blacks, regardless of APOL1 genotype, had significantly greater increases in mid-blood pressure and were more likely to experience significantly increasing mid-blood pressure trajectories with adjusted relative risk ratios of 5.21 and 7.27 for moderate-increasing and elevated-increasing versus low-stable blood pressure, respectively. Among blacks, longitudinal mid-blood pressure changes and mid-blood pressure trajectory classification were similar by APOL1 risk status. Modeling systolic and diastolic blood pressure as outcomes yielded similar findings. From young adulthood to mid-life, blacks have greater blood pressure increases versus whites that are not fully explained by traditional risk factors. Thus APOL1 variants are not associated with longitudinal blood pressure in blacks.
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Affiliation(s)
- Teresa K Chen
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | - Michelle M Estrella
- Kidney Health Research Collaborative, Department of Medicine, University of California, San Francisco, California, USA; San Francisco VA Medical Center, San Francisco, California, USA
| | - Eric Vittinghoff
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
| | - Feng Lin
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
| | - Orlando M Gutierrez
- Division of Preventative Medicine, Department of Medicine, University of Alabama at Birmingham, Alabama, USA
| | - Holly Kramer
- Division of Nephrology, Department of Medicine, Loyola University, Maywood, Illinois, USA
| | - Cora E Lewis
- Division of Preventative Medicine, Department of Medicine, University of Alabama at Birmingham, Alabama, USA
| | - Jeffrey B Kopp
- Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA
| | - Norrina B Allen
- Division of Epidemiology, Department of Preventative Medicine, Northwestern University, Chicago, Illinois, USA
| | - Cheryl A Winkler
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical Research, Frederick National Laboratory, Frederick, Maryland, USA
| | - Kirsten B Bibbins-Domingo
- Kidney Health Research Collaborative, Department of Medicine, University of California, San Francisco, California, USA
| | - Carmen A Peralta
- Kidney Health Research Collaborative, Department of Medicine, University of California, San Francisco, California, USA; San Francisco VA Medical Center, San Francisco, California, USA
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Rotimi CN, Bentley AR, Doumatey AP, Chen G, Shriner D, Adeyemo A. The genomic landscape of African populations in health and disease. Hum Mol Genet 2017; 26:R225-R236. [PMID: 28977439 PMCID: PMC6075021 DOI: 10.1093/hmg/ddx253] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 06/19/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022] Open
Abstract
A deeper appreciation of the complex architecture of African genomes is critical to the global effort to understand human history, biology and differential distribution of disease by geography and ancestry. Here, we report on how the growing engagement of African populations in genome science is providing new insights into the forces that shaped human genomes before and after the Out-of-Africa migrations. As a result of this human evolutionary history, African ancestry populations have the greatest genomic diversity in the world, and this diversity has important ramifications for genomic research. In the case of pharmacogenomics, for instance, variants of consequence are not limited to those identified in other populations, and diversity within African ancestry populations precludes summarizing risk across different African ethnic groups. Exposure of Africans to fatal pathogens, such as Plasmodium falciparum, Lassa Virus and Trypanosoma brucei rhodesiense, has resulted in elevated frequencies of alleles conferring survival advantages for infectious diseases, but that are maladaptive in modern-day environments. Illustrating with cardiometabolic traits, we show that while genomic research in African ancestry populations is still in early stages, there are already many examples of novel and African ancestry-specific disease loci that have been discovered. Furthermore, the shorter haplotypes in African genomes have facilitated fine-mapping of loci discovered in other human ancestry populations. Given the insights already gained from the interrogation of African genomes, it is imperative to continue and increase our efforts to describe genomic risk in and across African ancestry populations.
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Affiliation(s)
- Charles N. Rotimi
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Amy R. Bentley
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Ayo P. Doumatey
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Guanjie Chen
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Daniel Shriner
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Adebowale Adeyemo
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, Bethesda, MD 20892, USA
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Apolipoprotein L1 risk variants associate with prevalent atherosclerotic disease in African American systemic lupus erythematosus patients. PLoS One 2017; 12:e0182483. [PMID: 28850570 PMCID: PMC5574561 DOI: 10.1371/journal.pone.0182483] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 07/19/2017] [Indexed: 12/30/2022] Open
Abstract
Objective Atherosclerosis is exaggerated in African American (AA) systemic lupus erythematosus (SLE) patients, with doubled cardiovascular disease (CVD) risk compared to White patients. The extent to which common Apolipoprotein L1 (APOL1) risk alleles (RA) contribute to this trend is unknown. This retrospective cohort study assessed prevalent atherosclerotic disease across APOL1 genotypes in AA SLE patients. Methods One hundred thirteen AA SLE subjects were APOL1-genotyped and stratified as having: zero risk alleles, one risk allele, or two risk alleles. Chart review assessed CVD manifestations including abdominal aortic aneurysm, angina, carotid artery disease, coronary artery disease, myocardial infarction, peripheral vascular disease, stroke, and vascular calcifications. Associations between the genotypes and a composite endpoint defined as one or more CVD manifestations were calculated using logistic regression. Symptomatic atherosclerotic disease, excluding incidental vascular calcifications, was also assessed. Results The 0-risk-allele, 1-risk-allele and 2-risk-allele groups, respectively, comprised 34%, 53%, and 13% of the cohort. Respectively, 13.2%, 41.7%, and 60.0% of the 0-risk allele, 1-risk-allele, and 2-risk-allele groups met the composite endpoint of atherosclerotic CVD (p = 0.001). Adjusting for risk factors–including smoking, ESRD, BMI >25 and hypertension–we observed an association between carrying one or more RA and atherosclerotic CVD (OR = 7.1; p = 0.002). For symptomatic disease, the OR was 3.5 (p = 0.02). In a time-to-event analysis, the proportion of subjects free from the composite primary endpoint, symptomatic atherosclerotic CVD, was higher in the 0-risk-allele group compared to the 1-risk-allele and 2-risk-allele groups (χ2 = 6.5; p = 0.04). Conclusions Taken together, the APOL1 RAs associate with prevalent atherosclerotic CVD in this cohort of AA SLE patients, perhaps reflecting a potentiating effect of SLE on APOL1-related cardiovascular phenotypes.
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Hughson MD, Hoy WE, Mott SA, Bertram JF, Winkler CA, Kopp JB. APOL1 Risk Variants Independently Associated With Early Cardiovascular Disease Death. Kidney Int Rep 2017; 3:89-98. [PMID: 29340318 PMCID: PMC5762961 DOI: 10.1016/j.ekir.2017.08.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/05/2017] [Accepted: 08/14/2017] [Indexed: 01/13/2023] Open
Abstract
Introduction The relationship of APOL1 renal risk variants to cardiovascular disease (CVD) is controversial and was the subject of this investigation. Methods Age, cause of death, and nephrosclerosis (the latter defined by glomerulosclerosis) were analyzed in the autopsies of 162 African Americans and 136 whites genotyped for APOL1 risk alleles. Results Sudden deaths represented >75% of CVD autopsies for both races and all-risk genotypes. The average ages of CVD deaths for African Americans with 1 and 2 APOL1 risk alleles were, respectively, 7.0 years (P = 0.02) and 12.2 years (P < 0.01) younger than African Americans with 0 risk alleles and 8.7 years (P = 0.01) and 13.9 years (P = 0.01) younger than whites. Age differences were not significant between African Americans and whites with 0 risk alleles (P = 0.61). The younger CVD deaths of African Americans were associated with less severe glomerulosclerosis with 2 (P = 0.01), although not 1 (P = 0.09), compared with 0 APOL1 risk alleles. Cardiomyopathy was found in 23% of African Americans with 1 and 2 risk alleles and significantly contributed to the lower age (P = 0.01). For non-CVD deaths, age differences were not seen by race (P = 0.28) or among African Americans by risk allele status (P = 0.38). Conclusion Carriage of 1 or 2 APOL1 risk alleles in African Americans was associated with earlier age deaths due to coronary artery disease and cardiomyopathy. For 2 risk alleles, the early age was independent of nephrosclerosis.
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Affiliation(s)
- Michael D Hughson
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Wendy E Hoy
- Centre for Chronic Disease, The University of Queensland, Brisbane, Queensland, Australia
| | - Susan A Mott
- Centre for Chronic Disease, The University of Queensland, Brisbane, Queensland, Australia
| | - John F Bertram
- Cardiovascular Program Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Monash University, Melbourne, Victoria, Australia
| | - Cheryl A Winkler
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, Leidos Biomedical Inc., Frederick National Laboratory, Frederick, Maryland, USA
| | - Jeffrey B Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, Bethesda, Maryland, USA
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Peng T, Wang L, Li G. The analysis of APOL1 genetic variation and haplotype diversity provided by 1000 Genomes project. BMC Nephrol 2017; 18:267. [PMID: 28800731 PMCID: PMC5553676 DOI: 10.1186/s12882-017-0675-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/19/2017] [Indexed: 11/20/2022] Open
Abstract
Background The APOL1 gene variants has been shown to be associated with an increased risk of multiple kinds of diseases, particularly in African Americans, but not in Caucasians and Asians. In this study, we explored the single nucleotide polymorphism (SNP) and haplotype diversity of APOL1 gene in different races provided by 1000 Genomes project. Methods Variants of APOL1 gene in 1000 Genome Project were obtained and SNPs located in the regulatory region or coding region were selected for genetic variation analysis. Total 2504 individuals from 26 populations were classified as four groups that included Africa, Europe, Asia and Admixed populations. Tag SNPs were selected to evaluate the haplotype diversities in the four populations by HaploStats software. Results APOL1 gene was surrounded by some of the most polymorphic genes in the human genome, variation of APOL1 gene was common, with up to 613 SNP (1000 Genome Project reported) and 99 of them (16.2%) with MAF ≥ 1%. There were 79 SNPs in the URR and 92 SNPs in 3’UTR. Total 12 SNPs in URR and 24 SNPs in 3’UTR were considered as common variants with MAF ≥ 1%. It is worth noting that URR-1 was presents lower frequencies in European populations, while other three haplotypes taken an opposite pattern; 3’UTR presents several high-frequency variation sites in a short segment, and the differences of its haplotypes among different population were significant (P < 0.01), UTR-1 and UTR-5 presented much higher frequency in African population, while UTR-2, UTR-3 and UTR-4 were much lower. APOL1 coding region showed that two SNP of G1 with higher frequency are actually pull down the haplotype H-1 frequency when considering all populations pooled together, and the diversity among the four populations be widen by the G1 two mutation (P1 = 3.33E-4 vs P2 = 3.61E-30). Conclusions The distributions of APOL1 gene variants and haplotypes were significantly different among the different populations, in either regulatory or coding regions. It could provide clues for the future genetic study of APOL1 related diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12882-017-0675-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ting Peng
- Renal Division and Institute of Nephrology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, No. 32, West 2nd Duan, 1st Circle Road, Qingyang District, Chengdu, Sichuan, People's Republic of China, 610072
| | - Li Wang
- Renal Division and Institute of Nephrology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, No. 32, West 2nd Duan, 1st Circle Road, Qingyang District, Chengdu, Sichuan, People's Republic of China, 610072
| | - Guisen Li
- Renal Division and Institute of Nephrology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, No. 32, West 2nd Duan, 1st Circle Road, Qingyang District, Chengdu, Sichuan, People's Republic of China, 610072.
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McLean NO, Robinson TW, Freedman BI. APOL1 Gene Kidney Risk Variants and Cardiovascular Disease: Getting to the Heart of the Matter. Am J Kidney Dis 2017; 70:281-289. [PMID: 28143671 PMCID: PMC5526726 DOI: 10.1053/j.ajkd.2016.11.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 11/01/2016] [Indexed: 12/12/2022]
Abstract
Apolipoprotein L1 gene (APOL1) renal risk variants exhibit strong genetic associations with a spectrum of nondiabetic kidney diseases in individuals with recent African ancestry. Relationships between APOL1 kidney risk variants and cardiovascular disease (CVD) susceptibility and CVD-related death remain controversial. Some studies detected an increased risk for CVD, whereas others support protection from death and subclinical CVD and cerebrovascular disease. Because treatments for nondiabetic kidney disease may target this gene and its protein products, it remains critical to clarify the potential extrarenal effects of APOL1 kidney risk variants. This review addresses the current literature on APOL1 associations with CVD, cerebrovascular disease, and death. Potential causes of disparate results between studies are discussed.
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Affiliation(s)
- Nicholas O McLean
- Section on Nephrology, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC
| | - Todd W Robinson
- Section on Nephrology, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC
| | - Barry I Freedman
- Section on Nephrology, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC.
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Robinson TW, Freedman BI. The Apolipoprotein L1 Gene and Cardiovascular Disease. Methodist Debakey Cardiovasc J 2017; 12:2-5. [PMID: 28298955 DOI: 10.14797/mdcj-12-4s1-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Relative to those with European ancestry, African Americans have an excess incidence of nondiabetic chronic kidney disease predominantly due to two coding renal-risk variants in the apolipoprotein L1 gene (APOL1). This APOL1-kidney disease association is independent of systemic hypertension or blood pressure. Recent reports describe extra-renal effects of the APOL1 G1 and G2 renal-risk variants on cardiovascular disease (CVD), subclinical atherosclerosis, lipoprotein particle concentrations, and survival. However, results have been less consistent than those seen in kidney disease, and the observed APOL1 associations with CVD vary from risk to protective. This manuscript reviews the relationships between APOL1 renal-risk variants and CVD, with an emphasis on study-specific factors that may have contributed to disparate observations. It is possible that APOL1 renal-risk variants impact the systemic vasculature, not only the kidneys. As novel therapies for APOL1-associated nephropathy are developed, APOL1 variant protein effects on large blood vessels and risk of CVD will need to be considered.
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Affiliation(s)
- Todd W Robinson
- Wake Forest School of Medicine, Winston-Salem, North Carolina
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Abstract
PURPOSE OF REVIEW The prevalence of cardiovascular disease differs among ethnic groups and along geographic boundaries. At present, most of the projected increase in mortality from cardiovascular disease occurs in sub-Saharan African, Chinese and Southeast Asian populations. Ethnic disparities in the prevalence of cardiovascular disease coincide with quantitative and qualitative differences in risk factors for cardiovascular disease. High plasma cholesterol is one of the most important preventable causes of ischemic heart disease. RECENT FINDINGS The current review summarizes recent evidence on ethnic differences in ischemic heart disease and its correlates with genetic and acquired differences in plasma lipid and lipoprotein levels. The nature of ethnic differences in plasma lipid levels, apolipoprotein L1 en lipoprotein(a) [Lp(a)] is outlined, and the effects of lipid-lowering therapy and future efforts and challenges regarding implementation are discussed. SUMMARY Ethnic differences in HDL-cholesterol (HDL-C), triglyceride levels and Lp(a) may impact ethnic differences in cardiovascular disease and result in higher residual risk during lipid-lowering therapy. Further efforts should be made to stimulate the use of statins in both high-income and low-income countries and study their effects in individuals with different ethnic backgrounds.
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Affiliation(s)
- Katia Gazzola
- aDepartment of Medical Sciences, University of Ferrara, Ferrara, Italy bDepartment of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands
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Chen TK, Appel LJ, Grams ME, Tin A, Choi MJ, Lipkowitz MS, Winkler CA, Estrella MM. APOL1 Risk Variants and Cardiovascular Disease: Results From the AASK (African American Study of Kidney Disease and Hypertension). Arterioscler Thromb Vasc Biol 2017; 37:1765-1769. [PMID: 28572159 DOI: 10.1161/atvbaha.117.309384] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/22/2017] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Among African Americans, the apolipoprotein L1 (APOL1) risk variants have been associated with various types of kidney disease and chronic kidney disease progression. We aimed to determine whether these same risk variants also confer an increased risk for cardiovascular disease. APPROACH AND RESULTS In a cohort of African Americans with hypertension-attributed chronic kidney disease followed for up to 12 years, we used Cox proportional hazards models to estimate the relative hazard of a composite cardiovascular disease outcome (cardiovascular death or hospitalization for myocardial infarction, cardiac revascularization procedure, heart failure, or stroke) for the APOL1 high- (2 risk variants) versus low-risk (0-1 risk variant) genotypes. We adjusted for age, sex, ancestry, smoking, heart disease history, body mass index, cholesterol, randomized treatment groups, and baseline and longitudinal estimated glomerular filtration rate, systolic blood pressure, and proteinuria. Among 693 participants with APOL1 genotyping available (23% high risk), the high-risk group had lower mean estimated glomerular filtration rate (44.7 versus 50.1 mL/min per 1.73 m2) and greater proteinuria (median 0.19 versus 0.06) compared with the low-risk group at baseline. There was no significant association between APOL1 genotypes and the composite cardiovascular disease outcome in both unadjusted (hazard ratio=1.23; 95% confidence interval: 0.83-1.81) and fully adjusted (hazard ratio=1.16; 95% confidence interval: 0.77-1.76) models; however, in using an additive model, APOL1 high-risk variants were associated with increased cardiovascular mortality. CONCLUSIONS Among African Americans with hypertension-attributed chronic kidney disease, APOL1 risk variants were not associated with an overall risk for cardiovascular disease although some signals for cardiovascular mortality were noted.
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Affiliation(s)
- Teresa K Chen
- From the Divisions of Nephrology (T.K.C., M.E.G., M.J.C.) and General Internal Medicine (L.J.A.), Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (L.J.A., M.E.G., A.T.); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.T.); Division of Nephrology and Hypertension, Department of Medicine, Georgetown University School of Medicine, Washington, DC (M.S.L.); Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical, Frederick National Laboratory, MD (C.A.W.); and Kidney Health Research Collaborative, Department of Medicine, San Francisco VA Medical Center and University of California (M.M.E.).
| | - Lawrence J Appel
- From the Divisions of Nephrology (T.K.C., M.E.G., M.J.C.) and General Internal Medicine (L.J.A.), Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (L.J.A., M.E.G., A.T.); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.T.); Division of Nephrology and Hypertension, Department of Medicine, Georgetown University School of Medicine, Washington, DC (M.S.L.); Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical, Frederick National Laboratory, MD (C.A.W.); and Kidney Health Research Collaborative, Department of Medicine, San Francisco VA Medical Center and University of California (M.M.E.)
| | - Morgan E Grams
- From the Divisions of Nephrology (T.K.C., M.E.G., M.J.C.) and General Internal Medicine (L.J.A.), Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (L.J.A., M.E.G., A.T.); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.T.); Division of Nephrology and Hypertension, Department of Medicine, Georgetown University School of Medicine, Washington, DC (M.S.L.); Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical, Frederick National Laboratory, MD (C.A.W.); and Kidney Health Research Collaborative, Department of Medicine, San Francisco VA Medical Center and University of California (M.M.E.)
| | - Adrienne Tin
- From the Divisions of Nephrology (T.K.C., M.E.G., M.J.C.) and General Internal Medicine (L.J.A.), Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (L.J.A., M.E.G., A.T.); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.T.); Division of Nephrology and Hypertension, Department of Medicine, Georgetown University School of Medicine, Washington, DC (M.S.L.); Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical, Frederick National Laboratory, MD (C.A.W.); and Kidney Health Research Collaborative, Department of Medicine, San Francisco VA Medical Center and University of California (M.M.E.)
| | - Michael J Choi
- From the Divisions of Nephrology (T.K.C., M.E.G., M.J.C.) and General Internal Medicine (L.J.A.), Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (L.J.A., M.E.G., A.T.); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.T.); Division of Nephrology and Hypertension, Department of Medicine, Georgetown University School of Medicine, Washington, DC (M.S.L.); Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical, Frederick National Laboratory, MD (C.A.W.); and Kidney Health Research Collaborative, Department of Medicine, San Francisco VA Medical Center and University of California (M.M.E.)
| | - Michael S Lipkowitz
- From the Divisions of Nephrology (T.K.C., M.E.G., M.J.C.) and General Internal Medicine (L.J.A.), Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (L.J.A., M.E.G., A.T.); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.T.); Division of Nephrology and Hypertension, Department of Medicine, Georgetown University School of Medicine, Washington, DC (M.S.L.); Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical, Frederick National Laboratory, MD (C.A.W.); and Kidney Health Research Collaborative, Department of Medicine, San Francisco VA Medical Center and University of California (M.M.E.)
| | - Cheryl A Winkler
- From the Divisions of Nephrology (T.K.C., M.E.G., M.J.C.) and General Internal Medicine (L.J.A.), Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (L.J.A., M.E.G., A.T.); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.T.); Division of Nephrology and Hypertension, Department of Medicine, Georgetown University School of Medicine, Washington, DC (M.S.L.); Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical, Frederick National Laboratory, MD (C.A.W.); and Kidney Health Research Collaborative, Department of Medicine, San Francisco VA Medical Center and University of California (M.M.E.)
| | - Michelle M Estrella
- From the Divisions of Nephrology (T.K.C., M.E.G., M.J.C.) and General Internal Medicine (L.J.A.), Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD (L.J.A., M.E.G., A.T.); Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (A.T.); Division of Nephrology and Hypertension, Department of Medicine, Georgetown University School of Medicine, Washington, DC (M.S.L.); Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health and Leidos Biomedical, Frederick National Laboratory, MD (C.A.W.); and Kidney Health Research Collaborative, Department of Medicine, San Francisco VA Medical Center and University of California (M.M.E.)
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Freedman BI, Rocco MV, Bates JT, Chonchol M, Hawfield AT, Lash JP, Papademetriou V, Sedor JR, Servilla K, Kimmel PL, Wall BM, Pajewski NM. APOL1 renal-risk variants do not associate with incident cardiovascular disease or mortality in the Systolic Blood Pressure Intervention Trial. Kidney Int Rep 2017; 2:713-720. [PMID: 28758155 PMCID: PMC5527675 DOI: 10.1016/j.ekir.2017.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Introduction Relationships between apolipoprotein L1 gene (APOL1) renal-risk variants (RRVs) and cardiovascular disease (CVD) remain controversial. To clarify associations between APOL1 and CVD, a total of 2568 African American Systolic Blood Pressure Intervention Trial (SPRINT) participants were assessed for the incidence of CVD events (primary composite including nonfatal myocardial infarction, acute coronary syndrome not resulting in myocardial infarction, nonfatal stroke, nonfatal acute decompensated heart failure, and CVD death), renal outcomes, and all-cause mortality. Methods Cox proportional hazards regression models were used, adjusting for age, sex, African ancestry proportion, and treatment group (systolic blood pressure target of <120 mm Hg vs. <140 mm Hg). Results Of the participants, 14% had 2 APOL1 RRVs; these individuals also had lower baseline estimated GFR and higher levels of albuminuria and BMI. After a median follow-up of 39 months, no significant association was observed between APOL1 RRVs and the primary composite CVD outcome, any of its components, or all-cause mortality (recessive or additive genetic models). APOL1 demonstrated a trend toward association with sustained 30% reduction in estimated GFR to <60 ml/min/1.73 m2 in those with normal kidney function at baseline (hazard ratio 1.64; 95% confidence interval = 0.85−2.93; P = 0.114, recessive model). Discussion APOL1 RRVs were not associated with incident CVD in high-risk hypertensive, nondiabetic African American participants in SPRINT.
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Affiliation(s)
- Barry I Freedman
- Department of Internal Medicine, Section on Nephrology; Wake Forest School of Medicine, Winston-Salem, NC
| | - Michael V Rocco
- Department of Internal Medicine, Section on Nephrology; Wake Forest School of Medicine, Winston-Salem, NC
| | - Jeffrey T Bates
- Michael E. DeBakey Veterans Administration Medical Center and Baylor College of Medicine, Houston, TX
| | - Michel Chonchol
- Department of Medicine, Division of Renal Diseases and Hypertension; University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Amret T Hawfield
- Department of Internal Medicine, Section on Nephrology; Wake Forest School of Medicine, Winston-Salem, NC
| | - James P Lash
- Department of Medicine, Division of Nephrology; University of Illinois, Chicago, IL
| | - Vasilios Papademetriou
- Center for Hypertension, Kidney & Vascular Research; Georgetown University Medical Center, Washington, DC
| | - John R Sedor
- Department of Medicine; MetroHealth Medical Center and Department of Physiology and Biophysics; Case Western Reserve University, Cleveland, OH
| | - Karen Servilla
- Internal Medicine, Renal Section; New Mexico Veterans Administration Health Care System, Albuquerque, NM
| | - Paul L Kimmel
- National Institute of Diabetes and Digestive and Kidney Diseases; Bethesda, MD
| | - Barry M Wall
- Department of Nephrology; University of Tennessee Health Science Center and Veterans Affairs Medical Center, Memphis, TN
| | - Nicholas M Pajewski
- Department of Biostatistical Sciences, Division of Public Health Sciences; Wake Forest School of Medicine, Winston-Salem, NC
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Abstract
PURPOSE OF REVIEW Systemic lupus erythematosus (SLE) confers up to a 50-fold increased risk of cardiovascular disease (CVD), and African Americans with SLE experience accelerated damage accrual and doubled cardiovascular risk when compared to their European American counterparts. RECENT FINDINGS Genome-wide association studies have identified a substantial signal at 22q13, now assigned to variation at apolipoprotein L1 (APOL1), which has associated with progressive nondiabetic nephropathy, cardiovascular disease, and many immune-associated renal diseases, including lupus nephritis. We contend that alterations in crucial APOL1 intracellular pathways may underpin associated disease states based on structure-functional differences between variant and ancestral forms. While ancestral APOL1 may be a key driver of autophagy, nonconserved primary structure changes result in a toxic gain of function with attenuation of autophagy and an unsupervised pore-forming feature. Thus, the divergent intracellular biological pathways of ancestral and variant APOL1 may explain a worsened prognosis as demonstrated in SLE.
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64
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Mouton CP, Hayden M, Southerland JH. Cardiovascular Health Disparities in Underserved Populations. Prim Care 2017; 44:e37-e71. [DOI: 10.1016/j.pop.2016.09.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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65
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Ku E, Lipkowitz MS, Appel LJ, Parsa A, Gassman J, Glidden DV, Smogorzewski M, Hsu CY. Strict blood pressure control associates with decreased mortality risk by APOL1 genotype. Kidney Int 2017; 91:443-450. [PMID: 27927600 PMCID: PMC5237400 DOI: 10.1016/j.kint.2016.09.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 09/14/2016] [Accepted: 09/15/2016] [Indexed: 02/06/2023]
Abstract
Although APOL1 high-risk genotype partially accounts for the increased susceptibility of blacks to chronic kidney disease (CKD), whether APOL1 associates differentially with mortality risk remains controversial. Here we evaluate the association between APOL1 genotype and risk of death and determine whether APOL1 status modifies the association between strict versus usual blood pressure control and mortality risk. We performed a retrospective analysis of the African American Study of Kidney Disease and Hypertension trial that randomized black participants with CKD to strict versus usual blood pressure control from 1995 to 2001. This included 682 participants with known APOL1 genotype (157 with high-risk genotype) previously assigned to either strict (mean arterial pressure [MAP] 92 mm Hg or less) versus usual blood pressure control (MAP 102-107 mm Hg) during the trial. During a median follow-up of 14.5 years, risk of death did not differ between individuals with high- versus low-risk APOL1 genotypes (unadjusted hazard ratio 1.00 [95% confidence interval 0.76-1.33]). However, a significant interaction was detected between the APOL1 risk group and blood pressure control strategy. In the APOL1 high-risk group, the risk of death was 42% lower comparing strict versus usual blood pressure control (0.58 [0.35-0.97]). In the APOL1 low-risk group, the risk of death comparing strict versus usual blood pressure control was not significantly different (1.09 [0.84-1.43]). Thus, strict blood pressure control during CKD associates with a lower risk of death in blacks with the high-risk CKD APOL1 genotype. Knowledge of APOL1 status could inform selection of blood pressure treatment targets in black CKD patients.
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Affiliation(s)
- Elaine Ku
- Division of Nephrology, Department of Medicine, University of California, San Francisco, San Francisco, California, USA; Division of Pediatric Nephrology, Department of Pediatrics, University of California, San Francisco, San Francisco, California, USA.
| | - Michael S Lipkowitz
- Division of Nephrology, Department of Medicine, Georgetown University, Washington, DC, USA
| | - Lawrence J Appel
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, Maryland, USA
| | - Afshin Parsa
- Division of Nephrology, Department of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Medicine, Baltimore VA Medical Center, Baltimore, Maryland, USA
| | - Jennifer Gassman
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio, USA
| | - David V Glidden
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, USA
| | - Miroslaw Smogorzewski
- Division of Nephrology and Hypertension, Department of Medicine, University of Southern California, Los Angeles, California, USA
| | - Chi-Yuan Hsu
- Division of Nephrology, Department of Medicine, University of California, San Francisco, San Francisco, California, USA
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66
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Buraczynska M, Ksiazek K, Zukowski P, Grzebalska A. Interleukin-18 gene polymorphism and risk of CVD in older patients with type 2 diabetes mellitus. Diabetes Res Clin Pract 2016; 121:178-183. [PMID: 27741477 DOI: 10.1016/j.diabres.2016.09.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/13/2016] [Accepted: 09/22/2016] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Interleukin-18 (IL-18), a proinflammatory cytokine, plays a key role in the acute and chronic inflammatory processes. It is associated with risk of developing cardiovascular disease (CVD). The aim of this study was to evaluate association between G(-137)C polymorphism (rs187238) in the IL-18 gene and risk of diabetes and CVD in type 2 diabetes patients. METHODS We examined 1548 T2DM patients and 590 controls. All subjects were genotyped for the G(-137)C promoter region polymorphism by polymerase chain reaction (PCR-SSP). RESULTS Genotype distribution of the G(-137)C polymorphism showed no significant difference between T2DM patients and controls (p=0.115). An association with CVD was analyzed in two age groups: ⩾65 and <65years. In patients younger than 65years there was a tendency to association of CC genotype with CAD (OR 1.87, 95% CI 1.0-3, p=0.051). In contrast, in subjects aged 65 or older, the C allele and CC genotype showed the significant association with the presence of CVD, with the OR 1.99, p=0.001 and OR 5.31, p=0.006, respectively. The C allele carriers showed the higher prevalence of CVD compared to non-carriers (61% vs. 39%, p<0.0001). CONCLUSION Older T2DM patients carrying the C allele of IL-18 G(-137)C polymorphism have a significantly increased risk of CVD.
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Affiliation(s)
| | - Katarzyna Ksiazek
- Department of Nephrology, Medical University of Lublin, Lublin, Poland
| | - Pawel Zukowski
- Department of Nephrology, Medical University of Lublin, Lublin, Poland
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Pharmacogenomic implications of the evolutionary history of infectious diseases in Africa. THE PHARMACOGENOMICS JOURNAL 2016; 17:112-120. [PMID: 27779243 PMCID: PMC5380847 DOI: 10.1038/tpj.2016.78] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/06/2016] [Accepted: 07/19/2016] [Indexed: 12/20/2022]
Abstract
As the common birthplace of all human populations, modern humans have lived longer on the African continent than in any other geographical region of the world. This long history, along with the evolutionary need to adapt to environmental challenges such as exposure to infectious agents, has led to greater genetic variation in Africans. The vast genetic variation in Africans also extends to genes involved in the absorption, distribution, metabolism and excretion of pharmaceuticals. Ongoing cataloging of these clinically relevant variants reveals huge allele-frequency differences within and between African populations. Here, we examine Africa's large burden of infectious disease, discuss key examples of known genetic variation modulating disease risk, and provide examples of clinically relevant variants critical for establishing dosing guidelines. We propose that a more systematic characterization of the genetic diversity of African ancestry populations is required if the current benefits of precision medicine are to be extended to these populations.
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68
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Rotimi CN, Tekola-Ayele F, Baker JL, Shriner D. The African diaspora: history, adaptation and health. Curr Opin Genet Dev 2016; 41:77-84. [PMID: 27644073 DOI: 10.1016/j.gde.2016.08.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 06/30/2016] [Accepted: 08/02/2016] [Indexed: 01/13/2023]
Abstract
The trans-Atlantic slave trade brought millions of Africans to the New World. Advances in genomics are providing novel insights into the history and health of Africans and the diasporan populations. Recent examples reviewed here include the unraveling of substantial hunter-gatherer and 'Eurasian' admixtures across sub-Saharan Africa, expanding our understanding of ancestral African genetics; the global ubiquity of mixed ancestry; the revealing of African ancestry in Latin Americans that likely derived from the slave trade; and understanding of the ancestral backgrounds of APOL1 and LPL found to influence kidney disease and lipid levels, respectively, providing specific insights into disease etiology and health disparities.
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Affiliation(s)
- Charles N Rotimi
- Center for Research on Genomics and Global Health National Human Genome Research Institute, Building 12A, Room 4047 12 South Drive, Bethesda, MD 20892, USA.
| | - Fasil Tekola-Ayele
- Center for Research on Genomics and Global Health National Human Genome Research Institute, Building 12A, Room 4047 12 South Drive, Bethesda, MD 20892, USA
| | - Jennifer L Baker
- Center for Research on Genomics and Global Health National Human Genome Research Institute, Building 12A, Room 4047 12 South Drive, Bethesda, MD 20892, USA
| | - Daniel Shriner
- Center for Research on Genomics and Global Health National Human Genome Research Institute, Building 12A, Room 4047 12 South Drive, Bethesda, MD 20892, USA
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69
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Babintseva YD, Camont L, Chapman J, Lhomme M, Karagodin VP, Kontush A, Orekhov AN. The biological activity of high-density lipoprotein fractions and their role in the development of cardiovascular diseases. TERAPEVT ARKH 2016. [DOI: 10.17116/terarkh2016889111-118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Increasing the human plasma concentration of high-density lipoproteins (HDL) may be part of strategy for control of cardiovascular diseases (CVD). HDL particles vary in their structure, metabolism, and biological activity. The review describes major HDL fractions (subpopulations) and discusses new findings on the antiatherogenic properties of HDL particles. The whole spectrum of HDL fractions, small, dense, protein-rich lipoproteins, has atheroprotective properties that are determined by the presence of specialized groups of proteins and lipids; however, this activity may be decreased in atherogenic lesion. Comprehensive structural and compositional analysis of HDL may provide key information to identify the fractions that have characteristic biological properties and lose their functionality in CVD. These fractions may be also biomarkers for the risk of CVD and hence represent pharmacological targets.
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70
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Ma L, Langefeld CD, Comeau ME, Bonomo JA, Rocco MV, Burkart JM, Divers J, Palmer ND, Hicks PJ, Bowden DW, Lea JP, Krisher JO, Clay MJ, Freedman BI. APOL1 renal-risk genotypes associate with longer hemodialysis survival in prevalent nondiabetic African American patients with end-stage renal disease. Kidney Int 2016; 90:389-395. [PMID: 27157696 PMCID: PMC4946964 DOI: 10.1016/j.kint.2016.02.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/24/2016] [Accepted: 02/25/2016] [Indexed: 01/13/2023]
Abstract
Relative to European Americans, evidence supports that African Americans with end-stage renal disease (ESRD) survive longer on dialysis. Renal-risk variants in the apolipoprotein L1 gene (APOL1), associated with nondiabetic nephropathy and less subclinical atherosclerosis, may contribute to dialysis outcomes. Here, APOL1 renal-risk variants were assessed for association with dialytic survival in 450 diabetic and 275 nondiabetic African American hemodialysis patients from Wake Forest and Emory School of Medicine outpatient facilities. Outcomes were provided by the ESRD Network 6-Southeastern Kidney Council Standardized Information Management System. Dates of death, receipt of a kidney transplant, and loss to follow-up were recorded. Outcomes were censored at the date of transplantation or through 1 July 2015. Multivariable Cox proportional hazards models were computed separately in patients with nondiabetic and diabetic ESRD, adjusting for the covariates age, gender, comorbidities, ancestry, and presence of an arteriovenous fistula or graft at dialysis initiation. In nondiabetic ESRD, patients with 2 (vs. 0/1) APOL1 renal-risk variants had significantly longer dialysis survival (hazard ratio 0.57), a pattern not observed in patients with diabetes-associated ESRD (hazard ratio 1.29). Thus, 2 APOL1 renal-risk variants are associated with longer dialysis survival in African Americans without diabetes, potentially relating to presence of renal-limited disease or less atherosclerosis.
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Affiliation(s)
- Lijun Ma
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Carl D Langefeld
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Division of Public Health Sciences, Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Mary E Comeau
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Division of Public Health Sciences, Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Jason A Bonomo
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Michael V Rocco
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - John M Burkart
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Jasmin Divers
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Division of Public Health Sciences, Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Nicholette D Palmer
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Center for Genomics and Personalized Medicine Research, Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Pamela J Hicks
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Donald W Bowden
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Center for Genomics and Personalized Medicine Research, Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Janice P Lea
- Division of Renal Medicine, Department of Internal Medicine, Emory School of Medicine, Atlanta, Georgia, USA
| | - Jenna O Krisher
- Southeastern Kidney Council Inc.-ESRD Network 6, Raleigh, North Carolina, USA
| | - Margo J Clay
- Southeastern Kidney Council Inc.-ESRD Network 6, Raleigh, North Carolina, USA
| | - Barry I Freedman
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA; Center for Genomics and Personalized Medicine Research, Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
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71
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Friedman DJ, Pollak MR. Apolipoprotein L1 and Kidney Disease in African Americans. Trends Endocrinol Metab 2016; 27:204-215. [PMID: 26947522 PMCID: PMC4811340 DOI: 10.1016/j.tem.2016.02.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 02/06/2023]
Abstract
Genetic variants in the Apolipoprotein L1 (APOL1) gene cause high rates of kidney disease in African Americans. These variants, found only in individuals with recent African ancestry, confer enhanced innate immunity against African trypanosomes. Although they are among the most powerful disease-causing common variants discovered to date, we are just beginning to understand how they promote kidney injury. Since APOL1 is present in only a few primate species, much of our current knowledge has come from natural experiments in humans and in vitro studies while awaiting the development of transgenic animal models. Understanding more about the function of ApoL1 and how the high-risk variants behave differently from other ApoL1 molecules is a high priority in kidney disease research.
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Affiliation(s)
- David J. Friedman
- Beth Israel Deaconess Medical Center, Harvard Medical School, 99 Brookline Avenue, RN301, Boston, MA. 02215, 617 667 0253
| | - Martin R. Pollak
- Beth Israel Deaconess Medical Center, Harvard Medical School, 99 Brookline Avenue, RN325E, Boston, MA. 02215, 617 667 0461
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72
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Sharma AK, Friedman DJ, Pollak MR, Alper SL. Structural characterization of the C-terminal coiled-coil domains of wild-type and kidney disease-associated mutants of apolipoprotein L1. FEBS J 2016; 283:1846-62. [PMID: 26945671 DOI: 10.1111/febs.13706] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 01/25/2016] [Accepted: 03/02/2016] [Indexed: 01/08/2023]
Abstract
Trypanosomes that cause sleeping sickness endocytose apolipoprotein L1 (APOL1)-containing trypanolytic factors from human serum, leading to trypanolytic death through generation of APOL1-associated lytic pores in trypanosomal membranes. The trypanosome Trypanosoma brucei rhodesiense counteracts trypanolysis by expressing the surface protein serum response-associated (SRA), which can bind APOL1 common variant G0 to block its trypanolytic activity. However, two missense variants in the C terminal predicted coiled-coil (CC) domains of human APOL1 G1 (S342G/I384M) and G2 (ΔN388Y389) decrease or abrogate APOL1 binding to T. brucei rhodesiense SRA, thus preserving APOL1 trypanolytic activity. These evolutionarily selected APOL1 missense variants, found at a high frequency in some populations of African descent, also confer elevated risk of kidney disease. Understanding the SRA-APOL1 interaction and the role of APOL1 G1 and G2 variants in kidney disease demands structural characterization of the APOL1 CC domain. Using CD, heteronuclear NMR, and molecular dynamics (MD) simulation on structural homology models, we report here unique and dynamic solution conformations of nephropathy variants G1 and G2 as compared with the common variant G0. Conformational plasticity in G1 and G2 CC domains led to interhelical α1-α2 approximation coupled with secondary structural changes and delimited motional properties absent in the G0 CC domain. The G1 substitutions conferred local structural changes principally along helix α1, whereas the G2 deletion altered the structure of both helix α2 and helix α1. These dynamic features of APOL1 CC variants likely reflect their intrinsic structural properties, and should help interpret future APOL1 structural studies and define the contribution of APOL1 risk variants to kidney disease.
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Affiliation(s)
- Alok K Sharma
- Nephrology Division, Harvard Medical School, Boston, MA, USA.,Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - David J Friedman
- Nephrology Division, Harvard Medical School, Boston, MA, USA.,Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Martin R Pollak
- Nephrology Division, Harvard Medical School, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Seth L Alper
- Nephrology Division, Harvard Medical School, Boston, MA, USA.,Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
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