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Stephens BY, Young BE, Nandadeva D, Skow RJ, Greaney JL, Brothers RM, Fadel PJ. Sympathetic transduction at rest and during cold pressor test in young healthy non-Hispanic Black and White women. Am J Physiol Regul Integr Comp Physiol 2023; 325:R682-R691. [PMID: 37781734 DOI: 10.1152/ajpregu.00073.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 09/01/2023] [Accepted: 09/20/2023] [Indexed: 10/03/2023]
Abstract
Non-Hispanic Black (BL) individuals have the highest prevalence of hypertension and cardiovascular disease (CVD) compared with all other racial/ethnic groups. Previous work focused on racial disparities in sympathetic control and blood pressure (BP) regulation between young BL and White (WH) adults, have mainly included men. Herein, we hypothesized that BL women would exhibit augmented resting sympathetic vascular transduction and greater sympathetic and BP reactivity to cold pressor test (CPT) compared with WH women. Twenty-eight young healthy women (BL: n = 14, 22 [Formula: see text] 4 yr; WH: n = 14, 22 [Formula: see text] 4 yr) participated. Beat-to-beat BP (Finometer), common femoral artery blood flow (duplex Doppler ultrasound), and muscle sympathetic nerve activity (MSNA; microneurography) were continuously recorded. In a subset (BL n = 10, WH n = 11), MSNA and BP were recorded at rest and during a 2-min CPT. Resting sympathetic vascular transduction was quantified as changes in leg vascular conductance (LVC) and mean arterial pressure (MAP) following spontaneous bursts of MSNA using signal averaging. Sympathetic and BP reactivity were quantified as changes in MSNA and MAP during the last minute of CPT. There were no differences in nadir LVC following resting MSNA bursts between BL (-8.70 ± 3.43%) and WH women (-7.30 ± 3.74%; P = 0.394). Likewise, peak increases in MAP following MSNA bursts were not different between groups (BL: +2.80 ± 1.42 mmHg; vs. WH: +2.99 ± 1.15 mmHg; P = 0.683). During CPT, increases in MSNA and MAP were also not different between BL and WH women, with similar transduction estimates between groups (ΔMAP/ΔMSNA; P = 0.182). These findings indicate that young, healthy BL women do not exhibit exaggerated sympathetic transduction or augmented sympathetic and BP reactivity during CPT.NEW & NOTEWORTHY This study was the first to comprehensively investigate sympathetic vascular transduction and sympathetic and BP reactivity during a cold pressor test in young, healthy BL women. We demonstrated that young BL women do not exhibit exaggerated resting sympathetic vascular transduction and do not have augmented sympathetic or BP reactivity during cold stress compared with their WH counterparts. Collectively, these findings suggest that alterations in sympathetic transduction and reactivity are not apparent in young, healthy BL women.
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Affiliation(s)
- Brandi Y Stephens
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
| | - Benjamin E Young
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Damsara Nandadeva
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
- Department of Physiology, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
| | - Rachel J Skow
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
| | - Jody L Greaney
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
| | - R Matthew Brothers
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, United States
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Samils L, Henricson J, Strömberg T, Fredriksson I, Iredahl F. Workload and sex effects in comprehensive assessment of cutaneous microcirculation. Microvasc Res 2023; 148:104547. [PMID: 37192688 DOI: 10.1016/j.mvr.2023.104547] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/25/2023] [Accepted: 05/11/2023] [Indexed: 05/18/2023]
Abstract
INTRODUCTION Workload and sex-related differences have been proposed as factors of importance when evaluating the microcirculation. Simultaneous assessments with diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) enable a comprehensive evaluation of the microcirculation. The aim of the study was to compare the response between sexes in the microcirculatory parameters red blood cell (RBC) tissue fraction, RBC oxygen saturation, average vessel diameter, and speed-resolved perfusion during baseline, cycling, and recovery, respectively. METHODS In 24 healthy participants (aged 20 to 30 years, 12 females), cutaneous microcirculation was assessed by LDF and DRS at baseline, during a workload generated by cycling at 75 to 80 % of maximal age-predicted heart rate, and recovery, respectively. RESULTS Females had significantly lower RBC tissue fraction and total perfusion in forearm skin microcirculation at all phases (baseline, workload, and recovery). All microvascular parameters increased significantly during cycling, most evident in RBC oxygen saturation (34 % increase on average) and perfusion (9-fold increase in total perfusion). For perfusion, the highest speeds (>10 mm/s) increased by a factor of 31, whereas the lowest speeds (<1 mm/s) increased by a factor of 2. CONCLUSION Compared to a resting state, all studied microcirculation measures increased during cycling. For perfusion, this was mainly due to increased speed, and only to a minor extent due to increased RBC tissue fraction. Skin microcirculatory differences between sexes were seen in RBC concentration and total perfusion.
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Affiliation(s)
- Linda Samils
- Department of Health, Medicine and Caring Sciences, Division of Community Medicine, Linköping University, Linköping, Sweden
| | - Joakim Henricson
- Department of Emergency Medicine in Linköping, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Ingemar Fredriksson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Fredrik Iredahl
- Department of Health, Medicine and Caring Sciences, Division of Community Medicine, Linköping University, Linköping, Sweden.
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Kaze AD, Gao X, Musani SK, Bidulescu A, Bertoni AG, Abdalla M, Echouffo-Tcheugui JB. Association of plasma endothelin-1 with blood pressure progression among Blacks: The Jackson Heart Study. Am Heart J 2022; 246:144-151. [PMID: 34986393 PMCID: PMC8933059 DOI: 10.1016/j.ahj.2021.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 12/26/2021] [Accepted: 12/28/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Despite pathophysiological links between endothelin (ET)-1 and hypertension in Black adults, there is no population-based data appraising the association of plasma ET-1 with longitudinal blood pressure (BP) changes in Blacks. METHODS We analyzed data from 1197 Jackson Heart Study participants without hypertension (mean age 47.8 years [SD: 12.0]; 64.2% women), with plasma ET-1 available at the baseline examination (2000-2004). Poisson regression with robust variance was used to generate risk ratios (RRs) and 95% confidence intervals (CIs) of BP progression (an increase by ≥1 BP category based on the 2017 American College of Cardiology/American Heart Association classification) and incident hypertension (BP ≥ 130/80 mm Hg or use of antihypertensive medication) at follow-up (2005-2008 or 2009-2013). RESULTS Over a median follow-up of 7 years (range: 4-11), 71.2% (n = 854) progressed to a higher BP stage and 64.6% (n = 773) developed hypertension. After adjusting for possible confounders, each unit increment in baseline log (ET-1) was associated with higher risks of BP progression (RR 1.15 [95% CI 1.03-1.29], P = .016) and incident hypertension (RR 1.15 [95% CI 1.01-1.31], P = .032). Compared to those in the lowest ET-1 quartile, participants in the highest quartile had significantly higher risks of BP progression (RR 1.20 [95% CI 1.05-1.37], P = .007) and incident hypertension (RR 1.16 [95% CI 1.00-1.36], P = .052). CONCLUSIONS In a large, community-based sample of African Americans, higher plasma ET-1 concentrations were associated with higher risks of BP progression and incident hypertension.
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Affiliation(s)
| | - Xiang Gao
- Department of Epidemiology, Colorado State University, Fort Collins, CO
| | - Solomon K Musani
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS
| | - Aurelian Bidulescu
- Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN
| | - Alain G Bertoni
- Department of Epidemiology and Prevention, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Marwah Abdalla
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York, NY
| | - Justin B Echouffo-Tcheugui
- Department of Medicine, Division of Endocrinology, Diabetes & Metabolism, Johns Hopkins School of Medicine, Baltimore, MD.
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Akins JD, Richey RE, Campbell JC, Martin ZT, Olvera G, Brothers RM. Contributions of endothelin-1 and l-arginine to blunted cutaneous microvascular function in young, black women. Am J Physiol Heart Circ Physiol 2022; 322:H260-H268. [PMID: 34919455 PMCID: PMC8759956 DOI: 10.1152/ajpheart.00457.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Non-Hispanic black (BL) individuals have the greatest prevalence of cardiovascular disease (CVD), relative to other racial/ethnic groups (e.g., non-Hispanic white population; WH), which may be secondary to blunted vascular function. Although women typically present with reduced CVD relative to men of the same racial/ethnic group, the prevalence is similar between BL women and men though the mechanisms differ. This study hypothesized that reduced microvascular function in young, BL women is associated with endothelin-1 (ET-1) overactivity or insufficient l-arginine bioavailability. Nine BL and nine WH women participated (age: 20 ± 2 vs. 22 ± 2 yr). Cutaneous microvascular function was assessed during 39°C local heating, whereas lactated Ringer's (control), BQ-123 (ET-1 receptor type A antagonist), BQ-788 (ET-1 receptor type B antagonist), or l-arginine were infused via intradermal microdialysis to modify cutaneous vascular conductance (CVC). Subsequent infusion of Nω-nitro-l-arginine methyl ester allowed for quantification of the nitric oxide (NO) contribution to vasodilation, whereas combined sodium nitroprusside and 43°C heating allowed for normalization to maximal CVC (%CVCmax). BL women had blunted %CVCmax and NO contribution to dilation during the 39°C plateau (P < 0.027 for both). BQ-123 improved this response through augmented NO-mediated dilation (P < 0.048 for both). BQ-788 and l-arginine did not alter the CVC responses (P > 0.835 for both) or the NO contribution (P > 0.371 for both). Cutaneous microvascular function is reduced in BL women, and ET-1 receptor type A may contribute to this reduced function. Further research is needed to better characterize these mechanisms in young, BL women.NEW & NOTEWORTHY Cardiovascular disease remains a burden in the United States non-Hispanic black (BL) population, although its manifestation through blunted vasodilation in this population is different between men and women. Accordingly, this study determined that reduced microvascular function in young, BL women may be partially controlled by endothelin-1 (ET-1) type A receptors, although neither type B receptors nor insufficient l-arginine bioavailability seems to contribute to this response. Accordingly, further research is needed to better characterize these ET-1 related mechanisms and illuminate other pathways that may contribute to this disparate vascular function in young, BL women.
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Affiliation(s)
- John D. Akins
- 1Department of Kinesiology, The University of Texas at Arlington, Arlington, Texas
| | - Rauchelle E. Richey
- 1Department of Kinesiology, The University of Texas at Arlington, Arlington, Texas,2Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas
| | - Jeremiah C. Campbell
- 1Department of Kinesiology, The University of Texas at Arlington, Arlington, Texas
| | - Zachary T. Martin
- 1Department of Kinesiology, The University of Texas at Arlington, Arlington, Texas
| | - Guillermo Olvera
- 1Department of Kinesiology, The University of Texas at Arlington, Arlington, Texas,3Institute for Exercise and Environmental Medicine, Dallas, Texas
| | - R. Matthew Brothers
- 1Department of Kinesiology, The University of Texas at Arlington, Arlington, Texas
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Goel K, Hon SM, Farber HW, George MP. Pulmonary Arterial Hypertension: What Rare Diseases Tell Us About Disparities in Disease Registries, Clinical Trials, and Treatment Algorithms. Chest 2021; 160:1981-1983. [PMID: 34743846 DOI: 10.1016/j.chest.2021.06.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 11/26/2022] Open
Affiliation(s)
- Khushboo Goel
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado, Aurora, CO; Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, National Jewish Health, Denver, CO.
| | - Stephanie M Hon
- Division of Pulmonary, Critical Care, and Sleep Medicine, Tufts Medical Center, Boston, MA
| | - Harrison W Farber
- Division of Pulmonary, Critical Care, and Sleep Medicine, Tufts Medical Center, Boston, MA
| | - M Patricia George
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, National Jewish Health, Denver, CO
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Singh AT, Mothi SS, Li P, Sabbisetti V, Waikar SS, Mc Causland FR. Endothelin-1 and Parameters of Systolic Blood Pressure in Hemodialysis. Am J Hypertens 2021; 34:1203-1208. [PMID: 34192305 PMCID: PMC9526807 DOI: 10.1093/ajh/hpab104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 06/21/2021] [Accepted: 06/29/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Hypertension is common in hemodialysis (HD) patients. Increased blood pressure (BP) variability, particularly higher and lower extremes, is associated with adverse outcomes. We explored the association of endothelin-1 (ET-1), a potent vasoconstrictor, with different BP parameters (pre-HD, intra-HD, and post-HD) during HD in a contemporary patient cohort. METHODS This study uses the DaVita Biorepository, a longitudinal prospective cohort study with quarterly collection of clinical data and biospecimens. Unadjusted and adjusted linear mixed effects regression models were fit to determine association of pre-HD ET-1 (log-transformed and quartiles) with HD-related systolic BP (SBP) parameters (pre-HD, nadir intra-HD, and post-HD). As ET-1 was measured at baseline, analyses were restricted to 1 year of follow-up. RESULTS Among 769 participants, mean age was 52 years, 42% were females, and 41% were Black. Mean pre-HD SBP was 152 (±28) mm Hg and mean ET-1 concentration was 2.3 (±1.2) ng/ml. In fully adjusted models, each unit increase in SD of log-transformed ET-1 was associated with a 2.7 (95% confidence interval [CI] 1.5, 4.0) mm Hg higher pre-SBP; 1.6 (95% CI 0.9, 2.3) mm Hg higher nadir SBP; and 2.0 (95% CI 1.1, 2.9) mm Hg higher post-SBP. Each SD increase in log-transformed ET-1 was associated with 21% higher odds of experiencing intradialytic hypertension (odds ratio 1.21; 95% CI 1.10-1.34). CONCLUSIONS Higher baseline ET-1 levels are independently associated with higher SBP and higher odds of intradialytic hypertension. These results highlight a potential role for ET-1 in BP control in HD patients and raise the possibility of ET-1 antagonism as a therapeutic target.
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Affiliation(s)
- Anika T Singh
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA,Harvard Medical School, Boston, Massachusetts, USA,Correspondence: Anika T. Singh ()
| | - Suraj Sarvode Mothi
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA,Harvard Medical School, Boston, Massachusetts, USA
| | - Ping Li
- Department of Nephrology, State Key Laboratory of Kidney Disease, National Clinical Research Center for Kidney Disease, Chinese PLA General Hospital, Beijing, PR China
| | - Venkata Sabbisetti
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA,Harvard Medical School, Boston, Massachusetts, USA
| | - Sushrut S Waikar
- Section of Nephrology, Department of Medicine, Boston University School of Medicine and Boston Medical Center, Boston University, Boston, Massachusetts, USA
| | - Finnian R Mc Causland
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA,Harvard Medical School, Boston, Massachusetts, USA
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Feyaerts AF, Luyten W. Vitamin C as prophylaxis and adjunctive medical treatment for COVID-19? Nutrition 2020; 79-80:110948. [PMID: 32911430 PMCID: PMC7381407 DOI: 10.1016/j.nut.2020.110948] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 06/14/2020] [Accepted: 07/04/2020] [Indexed: 02/07/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 causes the potentially fatal coronavirus disease 2019 (COVID-19). Already during the outbreak of the severe acute respiratory syndrome coronavirus 1, the use of vitamin C was suggested. Many patients with severe COVID-19 have elevated levels of the mediators interleukin-6 and endothelin-1. These mediators may explain the age dependence of COVID-19 pneumonia, the preponderance of male and obese or hypertensive patients, as well as of persons of color and smokers. There is clear evidence that vitamin C in high doses can reduce these mediators. Vitamin C is cheap and safe. Hence, using a relatively low dose of vitamin C as prophylaxis, and in cases of severe COVID-19, an (intravenous) high-dose regimen may be beneficial. Ongoing clinical trials are expected to provide more definitive evidence.
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Affiliation(s)
- Adam F Feyaerts
- VIB Center for Microbiology, KU Leuven, Leuven, Belgium; Laboratory of Molecular Cell Biology, KU Leuven, Leuven, Belgium; Department of Technology, UCLL, Leuven, Belgium.
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Alcendor DJ. Dysregulation of Endothelin-1: Implications for Health Disparities in Alzheimer's Disease. J Pers Med 2020; 10:E199. [PMID: 33126567 PMCID: PMC7712547 DOI: 10.3390/jpm10040199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/24/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease (AD) and related dementias disproportionately impact racial and ethnic minorities. The racial and ethnic disparities in AD could be explained by differences in cerebral vascular disease pathology. Endothelin-1 (ET-1) is a potent vasoconstrictive peptide that regulates smooth muscle, endothelial cell, and pericyte contractions that may result in cerebral vascular constriction, leading to cerebral hypoperfusion; over time, ET-1 may result in neuronal injury contributing to the pathology of AD. Upregulation of the ET-1 system has been observed in African Americans when compared with non-Hispanic Whites. The role of the ET-1 system as a driver of ethnic disparities in AD requires further investigation. Targeting of the ET-1 system as a therapeutic intervention that could impact AD progression also needs further study. Dysregulation of ET-1 in Hispanic/Latino populations largely have been unexplored. Genetics linking ET-1 dysregulation and racial disparities in AD also needs further investigation. In this review, I examine how AD effects underserved minority populations and how dysregulation of the ET-1 system specifically predisposes ethnic minorities to AD. In addition, I examine the molecular interactions of the ET-1 system and amyloid beta, the role the ET-1 system in neurodegeneration, potential therapeutics for ET-1 dysregulation, and the impact on AD progression.
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Affiliation(s)
- Donald J Alcendor
- Center for AIDS Health Disparities Research, Department of Microbiology, Immunology and Physiology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA
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Brothers RM, Stephens BY, Akins JD, Fadel PJ. Influence of sex on heightened vasoconstrictor mechanisms in the non-Hispanic black population. FASEB J 2020; 34:14073-14082. [PMID: 32949436 DOI: 10.1096/fj.202001405r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/20/2020] [Accepted: 08/27/2020] [Indexed: 11/11/2022]
Abstract
Cardiovascular disease (CVD) affects individuals of all races and ethnicities; however, its prevalence is highest in non-Hispanic black individuals (BL) relative to other populations. While previous research has provided valuable insight into elevated CVD risk in the BL population, this work has been almost exclusively conducted in men. This is alarming given that BL women suffer from CVD at an equivalent rate to BL men and each has a greater prevalence when compared to all other ethnicities, regardless of sex. The importance of investigating sex differences in mechanisms of cardiovascular function is highlighted by the National Institute of Health requiring sex to be considered as a biological variable in research studies to better our "understanding of key sex influences on health processes and outcomes." The mechanism(s) responsible for the elevated CVD risk in BL women remains unclear and is likely multifactorial. Limited studies in BL women suggest that, while impaired vasodilator capacity is involved, heightened vasoconstrictor tone and/or responsiveness may also contribute. Within this mini-review, we will discuss potential mechanisms of elevated rates of hypertension and other CVDs in BL individuals with a particular focus on young, otherwise healthy, college-aged women. To stimulate academic thought and future research, we will also discuss potential mechanisms for impaired vascular function in BL women, as well as possible divergent mechanisms between BL men and women based on either preliminary data or plausible speculation extending from findings in the existing literature. Last, we will conclude with potential future research directions aimed at better understanding the elevated risk for hypertension and CVD in BL women.
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Affiliation(s)
| | | | - John D Akins
- Department of Kinesiology, University of Texas, Arlington, TX, USA
| | - Paul J Fadel
- Department of Kinesiology, University of Texas, Arlington, TX, USA
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10
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Barbosa TC, Young BE, Stephens BY, Nandadeva D, Kaur J, Keller DM, Fadel PJ. Functional sympatholysis is preserved in healthy young Black men during rhythmic handgrip exercise. Am J Physiol Regul Integr Comp Physiol 2020; 319:R323-R328. [PMID: 32783690 DOI: 10.1152/ajpregu.00105.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Black men have attenuated increases in forearm vascular conductance (FVC) and forearm blood flow (FBF) during moderate- and high-intensity rhythmic handgrip exercise compared with White men, but the underlying mechanisms are unclear. Here, we tested for the first time the hypothesis that functional sympatholysis (i.e., attenuation of sympathetic vasoconstriction in the exercising muscles) is impaired in Black men compared with White men. Thirteen White and 14 Black healthy young men were studied. FBF (duplex Doppler ultrasound) and mean arterial pressure (MAP; Finometer) were measured at rest and during rhythmic handgrip exercise at 30% maximal voluntary contraction. FVC was calculated as FBF/MAP. Sympathetic activation was induced via lower body negative pressure (LBNP) at -20 Torr for 2 min at rest and from the 3rd to the 5th min of handgrip. Sympathetic vasoconstriction was assessed as percent reductions in FVC during LBNP. The groups presented similar resting FVC, FBF, and MAP. During LBNP at rest, reductions in FVC were not different between White (-35 ± 10%) and Black men (-32 ± 14%, P = 0.616), indicating similar reflex-induced sympathetic vasoconstriction. During handgrip exercise, there were minimal reductions in FVC with LBNP in either group (White: -1 ± 7%; Black: +1 ± 8%; P = 0.523), indicating functional sympatholysis in both groups. Thus, contrary to our hypothesis, our findings indicate a preserved functional sympatholysis in healthy young Black men compared with White men, suggesting that this mechanism does not appear to contribute to reduced exercise hyperemia during moderate-intensity rhythmic handgrip in this population.
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Affiliation(s)
- Thales C Barbosa
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
| | - Benjamin E Young
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
| | - Brandi Y Stephens
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
| | - Damsara Nandadeva
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
| | - Jasdeep Kaur
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
| | - David M Keller
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
| | - Paul J Fadel
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
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11
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The endothelin system as target for therapeutic interventions in cardiovascular and renal disease. Clin Chim Acta 2020; 506:92-106. [DOI: 10.1016/j.cca.2020.03.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/05/2020] [Accepted: 03/05/2020] [Indexed: 12/12/2022]
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Brothers RM, Fadel PJ, Keller DM. Racial disparities in cardiovascular disease risk: mechanisms of vascular dysfunction. Am J Physiol Heart Circ Physiol 2019; 317:H777-H789. [PMID: 31397168 DOI: 10.1152/ajpheart.00126.2019] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cardiovascular disease (CVD) accounts for a third of all deaths in the United States making it the leading cause of morbidity and mortality. Although CVD affects individuals of all races/ethnicities, the prevalence of CVD is highest in non-Hispanic black (BL) individuals relative to other populations. The mechanism(s) responsible for elevated CVD risk in the BL population remains incompletely understood. However, impaired vascular vasodilator capacity and exaggerated vascular vasoconstrictor responsiveness are likely contributing factors, both of which are present even in young, otherwise healthy BL individuals. Within this review, we highlight some historical and recent data, collected from our laboratories, of impaired vascular function, in terms of reduced vasodilator capacity and heightened vasoconstrictor responsiveness, in the peripheral and cerebral circulations in BL individuals. We provide data that such impairments may be related to elevated oxidative stress and subsequent reduction in nitric oxide bioavailability. In addition, divergent mechanisms of impaired vasodilatory capacity between BL men and women are discussed. Finally, we propose several directions where future research is needed to fill in knowledge gaps, which will allow for better understanding of the mechanisms contributing to impaired vascular function in this population. Ultimately, this information will allow for better lifestyle and therapeutic approaches to be implemented in an effort to minimize the increased CVD burden in the BL population.
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Affiliation(s)
- R Matthew Brothers
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - David M Keller
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
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Yang S, Huang S, Daniels LB, Yeboah J, Lima JAC, Cannone V, Burnett JC, Beckman JA, Carr JJ, Wang TJ, Gupta DK. NT-proBNP, race and endothelial function in the Multi-Ethnic Study of Atherosclerosis. Heart 2019; 105:1590-1596. [PMID: 31152069 DOI: 10.1136/heartjnl-2019-314707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/04/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE Natriuretic peptides (NPs) are hormones with cardioprotective effects. NP levels vary by race; however, the pathophysiological consequences of lower NP levels are not well understood. We aimed to quantify the association between NPs and endothelial function as measured by flow-mediated dilation (FMD) and the contribution of NP levels to racial differences in endothelial function. METHODS In this cross-sectional study of 2938 Multi-Ethnic Study of Atherosclerosis participants (34% Caucasian, 20% African-American, 20% Asian-American and 26% Hispanic) without cardiovascular disease at baseline, multivariable linear regression models were used to examine the association between serum N-terminal pro-B-type NP (NT-proBNP) and natural log-transformed FMD. We also tested whether NT-proBNP mediated the relationship between race and FMD using the product of coefficients method. RESULTS Among African-American and Chinese-American individuals, lower NT-proBNP levels were associated with lower FMD, β=0.06 (95% CI: 0.03 to 0.09; p<0.001) and β=0.06 (95% CI: 0.02 to 0.09; p=0.002), respectively. Non-significant associations between NT-proBNP and FMD were found in Hispanic and Caucasian individuals. In multivariable models, endothelial function differed by race, with African-American individuals having the lowest FMD compared with Caucasians, p<0.001. Racial differences in FMD among African-Americans and Chinese-Americans were mediated in part by NT-proBNP levels (African-Americans, mediation effect: -0.03(95% CI: -0.05 to -0.01); Chinese-Americans, mediation effect: -0.03(95% CI: -0.05 to -0.01)). CONCLUSIONS Lower NP levels are associated with worse endothelial function among African-Americans and Chinese-Americans. A relative NP deficiency in some racial/ethnic groups may contribute to differences in vascular function.
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Affiliation(s)
- Sushan Yang
- Department of Medicine-Cardiology, University of Washington System, Seattle, Washington, USA
| | - Shi Huang
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Lori B Daniels
- Department of Medicine, UC San Diego, La Jolla, California, USA
| | - Joseph Yeboah
- Medicine-Cardiovascular, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA
| | - Joao A C Lima
- Departments of Radiology and Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Valentina Cannone
- Cardiorenal Research Laboratory, Mayo Clinic Minnesota, Rochester, Minnesota, USA.,Department of Clinical and Experimental Medicine, University of Parma Medical School, Parma, Italy
| | - John C Burnett
- Cardiorenal Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic and Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Joshua A Beckman
- Department of Medicine-Cardiology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - J Jeffrey Carr
- Department of Radiology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Thomas J Wang
- Department of Medicine-Cardiology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Deepak K Gupta
- Department of Medicine-Cardiology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Medrek SK, Sahay S. Ethnicity in Pulmonary Arterial Hypertension: Possibilities for Novel Phenotypes in the Age of Personalized Medicine. Chest 2017; 153:310-320. [PMID: 28887060 DOI: 10.1016/j.chest.2017.08.1159] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 12/18/2022] Open
Abstract
In the past decade and a half, the introduction of new therapeutic agents has revolutionized the management of pulmonary arterial hypertension (PAH). These new treatment options have improved the quality of life and survival in PAH. With an armamentarium of options available, the identification of unique phenotypes can help practitioners choose tailored treatment regimens. Experts in other cardiovascular diseases, such as congestive heart failure and hypertension, have recommended race-specific treatments in their fields based on data highlighting variations in response to therapies. With this perspective, we review evidence supporting the hypothesis that ethnicity or race plays an important role in the management of PAH. Preliminary research suggests that races/ethnicities have differences in the presentation and outcome of PAH and could respond to PAH-specific medications with varying efficacy. Genetic, physiological, and anatomic differences exist between races, particularly regarding the structure and function of the right ventricle. Unfortunately, clinical trials have not adequately included minorities, and registry data often omit inclusion of this demographic information. Further studies are needed to characterize the role that ethnicity plays in the prevalence, presentation, outcomes, and optimal treatment of PAH.
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Affiliation(s)
- Sarah K Medrek
- Division of Pulmonary, Critical Care, and Sleep Medicine, Baylor College of Medicine, Houston, TX
| | - Sandeep Sahay
- Department of Medicine, Weill Cornell Medical College and Institute of Academic Medicine, Houston Methodist Hospital, Houston, TX.
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15
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Singh R, Verma A, Aljabari S, Vasylyeva TL. Urinary biomarkers as indicator of chronic inflammation and endothelial dysfunction in obese adolescents. BMC OBESITY 2017; 4:11. [PMID: 28344817 PMCID: PMC5361775 DOI: 10.1186/s40608-017-0148-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 02/11/2017] [Indexed: 01/10/2023]
Abstract
Background Obesity is a pro-inflammatory state that may predispose patients to acute coronary syndrome characterized by chronic low grade inflammation resulting in endothelial dysfunction (ED). The aim of the study was to evaluate urinary biomarkers of inflammation and ED in adolescents with obesity. Methods Sixty three subjects were recruited for the study. Twenty healthy adolescents with normal body mass (NW), 14 overweight (OW), 29 obese (OA) subjects were selected. An EndoPat 2000 device was used to measure the reactive hyperemia index (RHI). First morning fasting urine samples were tested for interleukin 6 (IL-6), endothelin 1 (ET-1), alpha-1-acid glycoprotein (AGP), tumor necrosis factor- α (TNF-α) and corrected to urinary creatinine. Results Urinary TNF-α was significantly higher in OA group (52.4 ± 15.3 pg/mg) compared to adolescents with NW (14.1 ± 1.2 pg/mg, P = 0.04). ET-1 levels were found to be higher in OW (5.18 ± 1.6 pg/mg) compared with NW (3 · 47 ± 0.3 pg/mg, P = 0.24); and higher in OA (8.48 ± 3.1 pg/mg) compared to both NW (P = 0.19) and OW (P = 0.40). Similarly a higher AGP level was observed in OW (864.8 ± 156 ng/mg) and OA (808.3 ± 186 ng/mg) compared to NW (653 ± 69 ng/mg) (P = 0.16 & 0.49 respectively). Inflammatory markers namely, TNF-α, IL-6 and AGP significantly and positively correlated with each other and with ET-1, a marker for endothelial dysfunction. This significant correlation was also observed when tested separately in the subgroups (NW, OW and OA). There were no differences in RHI levels among the study groups. Conclusion Urinary TNF-alpha is significantly elevated in obese adolescents and correlates with urinary ET-1, which is recognized as a biomarker for endothelial dysfunction. Since obesity is a chronic inflammatory state, elevated urinary TNF-alpha might be used as a non invasive tool to monitor the level of that inflammation.
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Affiliation(s)
- Ruchi Singh
- Department of Pediatrics, Texas Tech University Health Sciences Center, 1400 S. Coulter, Amarillo, TX 79106 USA
| | - Arushi Verma
- Department of Pediatrics, Texas Tech University Health Sciences Center, 1400 S. Coulter, Amarillo, TX 79106 USA
| | - Salim Aljabari
- Department of Pediatrics, Texas Tech University Health Sciences Center, 1400 S. Coulter, Amarillo, TX 79106 USA
| | - Tetyana L Vasylyeva
- Department of Pediatrics, Texas Tech University Health Sciences Center, 1400 S. Coulter, Amarillo, TX 79106 USA
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Klassen SA, Chirico D, O'Leary DD, Cairney J, Wade TJ. Linking systemic arterial stiffness among adolescents to adverse childhood experiences. CHILD ABUSE & NEGLECT 2016; 56:1-10. [PMID: 27107504 DOI: 10.1016/j.chiabu.2016.04.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/30/2016] [Accepted: 04/06/2016] [Indexed: 05/16/2023]
Abstract
Adverse childhood experiences (ACEs) have been linked with cardiovascular disease and early mortality among adults. Most research examines this relationship retrospectively. Examining the association between ACEs and children's cardiovascular health is required to understand the time course of this association. We examined the relationship between ACEs exposure and ECG-to-toe pulse wave velocity (PWV), a measure of systemic arterial stiffness that is strongly related to cardiovascular mortality among adults. PWV (distance/transit time; m/s) was calculated using transit times from the ECG R-wave to the pulse wave contour at the toe. Transit times were collected over 15 heartbeats and the distance from the sternal notch to the left middle toe was used. A total of 221 children (119 females) aged 10-14 years participated in data collection of PWV, hemodynamic and anthropometric variables. Parents of these children completed a modified inventory of ACEs taken from the Childhood Trust Events Survey. Multivariable regression assessed the relationship between ACEs group (<4 ACEs versus ≥4 ACEs) and PWV. Analyses yielded an ACEs group by sex interaction, with males who experienced four or more ACEs having higher PWV (p<0.01). This association was independent of hemodynamic, anthropometric and sociodemographic variables (R(2)=0.346; p<0.01). Four or more ACEs is associated with greater arterial stiffness in male children aged 10-14 years. Addressing stress and trauma exposure in childhood is an important target for public health interventions to reduce early cardiovascular risk.
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Affiliation(s)
| | - Daniele Chirico
- Faculty of Applied Health Sciences, Brock University, Canada
| | - Deborah D O'Leary
- Faculty of Applied Health Sciences, Brock University, Canada; Department of Health Sciences, Brock University, Canada
| | - John Cairney
- Departments of Family Medicine, Psychiatry, and Kinesiology, McMaster University, Canada
| | - Terrance J Wade
- Faculty of Applied Health Sciences, Brock University, Canada; Department of Health Sciences, Brock University, Canada.
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Charkoudian N, Wallin BG. Sympathetic neural activity to the cardiovascular system: integrator of systemic physiology and interindividual characteristics. Compr Physiol 2014; 4:825-50. [PMID: 24715570 DOI: 10.1002/cphy.c130038] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The sympathetic nervous system is a ubiquitous, integrating controller of myriad physiological functions. In the present article, we review the physiology of sympathetic neural control of cardiovascular function with a focus on integrative mechanisms in humans. Direct measurement of sympathetic neural activity (SNA) in humans can be accomplished using microneurography, most commonly performed in the peroneal (fibular) nerve. In humans, muscle SNA (MSNA) is composed of vasoconstrictor fibers; its best-recognized characteristic is its participation in transient, moment-to-moment control of arterial blood pressure via the arterial baroreflex. This property of MSNA contributes to its typical "bursting" pattern which is strongly linked to the cardiac cycle. Recent evidence suggests that sympathetic neural mechanisms and the baroreflex have important roles in the long term control of blood pressure as well. One of the striking characteristics of MSNA is its large interindividual variability. However, in young, normotensive humans, higher MSNA is not linked to higher blood pressure due to balancing influences of other cardiovascular variables. In men, an inverse relationship between MSNA and cardiac output is a major factor in this balance, whereas in women, beta-adrenergic vasodilation offsets the vasoconstrictor/pressor effects of higher MSNA. As people get older (and in people with hypertension) higher MSNA is more likely to be linked to higher blood pressure. Skin SNA (SSNA) can also be measured in humans, although interpretation of SSNA signals is complicated by multiple types of neurons involved (vasoconstrictor, vasodilator, sudomotor and pilomotor). In addition to blood pressure regulation, the sympathetic nervous system contributes to cardiovascular regulation during numerous other reflexes, including those involved in exercise, thermoregulation, chemoreflex regulation, and responses to mental stress.
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Affiliation(s)
- N Charkoudian
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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18
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Maley MJ, Eglin CM, House JR, Tipton MJ. The effect of ethnicity on the vascular responses to cold exposure of the extremities. Eur J Appl Physiol 2014; 114:2369-79. [PMID: 25081130 DOI: 10.1007/s00421-014-2962-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/17/2014] [Indexed: 11/25/2022]
Abstract
PURPOSE Cold injuries are more prevalent in individuals of African descent (AFD). Therefore, we investigated the effect of extremity cooling on skin blood flow (SkBF) and temperature (T sk) between ethnic groups. METHODS Thirty males [10 Caucasian (CAU), 10 Asian (ASN), 10 AFD] undertook three tests in 30 °C air whilst digit T sk and SkBF were measured: (i) vasomotor threshold (VT) test--arm immersed in 35 °C water progressively cooled to 10 °C and rewarmed to 35 °C to identify vasoconstriction and vasodilatation; (ii) cold-induced vasodilatation (CIVD) test--hand immersed in 8 °C water for 30 min followed by spontaneous warming; (iii) cold sensitivity (CS) test--foot immersed in 15 °C water for 2 min followed by spontaneous warming. Cold sensory thresholds of the forearm and finger were also assessed. RESULTS In the VT test, vasoconstriction and vasodilatation occurred at a warmer finger T sk in AFD during cooling [21.2 (4.4) vs. 17.0 (3.1) °C, P = 0.034] and warming [22.0 (7.9) vs. 12.1 (4.1) °C, P = 0.002] compared with CAU. In the CIVD test, average SkBF during immersion was greater in CAU [42 (24) %] than ASN [25 (8) %, P = 0.036] and AFD [24 (13) %, P = 0.023]. Following immersion, SkBF was higher and rewarming faster in CAU [3.2 (0.4) °C min(-1)] compared with AFD [2.5 (0.7) °C min(-1), P = 0.037], but neither group differed from ASN [3.0 (0.6) °C min(-1)]. Responses to the CS test and cold sensory thresholds were similar between groups. CONCLUSION AFD experienced a more intense protracted finger vasoconstriction than CAU during hand immersion, whilst ASN experienced an intermediate response. This greater sensitivity to cold may explain why AFD are more susceptible to cold injuries.
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Affiliation(s)
- Matthew J Maley
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, PO1 2ER, UK,
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Su S, Wang X, Kapuku GK, Treiber FA, Pollock DM, Harshfield GA, McCall WV, Pollock JS. Adverse childhood experiences are associated with detrimental hemodynamics and elevated circulating endothelin-1 in adolescents and young adults. Hypertension 2014; 64:201-7. [PMID: 24777980 DOI: 10.1161/hypertensionaha.113.02755] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Growing evidence suggests that adverse childhood experiences (ACEs) increase the risks for coronary heart disease and hypertension in mid and late adulthood. We previously reported that early life stress induces a hyperreactive endothelin-dependent cardiovascular phenotype in a rat model. In the present study, we evaluated whether exposure to ACEs is associated with greater peripheral resistance, arterial stiffness, blood pressure, or elevated circulating endothelin-1 levels in humans. In 221 healthy adolescents and young adults (mean age, 21 years; range, 13-29 years), we found a graded association of ACE exposure with plasma endothelin-1 levels, of which on average 18% and 24% were higher in participants with 1 ACE and ≥2 ACEs, respectively, compared with those with no ACEs (P=0.001). Participants with moderate/severe exposure to ACEs (≥2 ACEs) had significantly higher total peripheral resistance index (+12%), diastolic blood pressure (+5%), and pulse wave velocity (+9%) compared with those who were not exposed. These associations were independent of age, race, sex, body mass index, and childhood socioeconomic status. Our results indicate that early life stress promotes cardiovascular disease risk, specifically detrimental vascular and cardiac function, detectable in young adulthood.
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Affiliation(s)
- Shaoyong Su
- From the Georgia Prevention Center (S.S., X.W., G.K.K., G.A.H.), Department of Medicine (D.M.P., J.S.P.), and Department of Psychiatry and Health Behavior (W.V.M.), Georgia Regents University, Augusta; Technology Applications Center for Healthful Lifestyles, Colleges of Nursing and Medicine, Medical University of South Carolina, Charleston (F.A.T.); and Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham (D.M.P., J.S.P.)
| | - Xiaoling Wang
- From the Georgia Prevention Center (S.S., X.W., G.K.K., G.A.H.), Department of Medicine (D.M.P., J.S.P.), and Department of Psychiatry and Health Behavior (W.V.M.), Georgia Regents University, Augusta; Technology Applications Center for Healthful Lifestyles, Colleges of Nursing and Medicine, Medical University of South Carolina, Charleston (F.A.T.); and Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham (D.M.P., J.S.P.)
| | - Gaston K Kapuku
- From the Georgia Prevention Center (S.S., X.W., G.K.K., G.A.H.), Department of Medicine (D.M.P., J.S.P.), and Department of Psychiatry and Health Behavior (W.V.M.), Georgia Regents University, Augusta; Technology Applications Center for Healthful Lifestyles, Colleges of Nursing and Medicine, Medical University of South Carolina, Charleston (F.A.T.); and Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham (D.M.P., J.S.P.)
| | - Frank A Treiber
- From the Georgia Prevention Center (S.S., X.W., G.K.K., G.A.H.), Department of Medicine (D.M.P., J.S.P.), and Department of Psychiatry and Health Behavior (W.V.M.), Georgia Regents University, Augusta; Technology Applications Center for Healthful Lifestyles, Colleges of Nursing and Medicine, Medical University of South Carolina, Charleston (F.A.T.); and Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham (D.M.P., J.S.P.)
| | - David M Pollock
- From the Georgia Prevention Center (S.S., X.W., G.K.K., G.A.H.), Department of Medicine (D.M.P., J.S.P.), and Department of Psychiatry and Health Behavior (W.V.M.), Georgia Regents University, Augusta; Technology Applications Center for Healthful Lifestyles, Colleges of Nursing and Medicine, Medical University of South Carolina, Charleston (F.A.T.); and Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham (D.M.P., J.S.P.)
| | - Gregory A Harshfield
- From the Georgia Prevention Center (S.S., X.W., G.K.K., G.A.H.), Department of Medicine (D.M.P., J.S.P.), and Department of Psychiatry and Health Behavior (W.V.M.), Georgia Regents University, Augusta; Technology Applications Center for Healthful Lifestyles, Colleges of Nursing and Medicine, Medical University of South Carolina, Charleston (F.A.T.); and Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham (D.M.P., J.S.P.)
| | - W Vaughn McCall
- From the Georgia Prevention Center (S.S., X.W., G.K.K., G.A.H.), Department of Medicine (D.M.P., J.S.P.), and Department of Psychiatry and Health Behavior (W.V.M.), Georgia Regents University, Augusta; Technology Applications Center for Healthful Lifestyles, Colleges of Nursing and Medicine, Medical University of South Carolina, Charleston (F.A.T.); and Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham (D.M.P., J.S.P.)
| | - Jennifer S Pollock
- From the Georgia Prevention Center (S.S., X.W., G.K.K., G.A.H.), Department of Medicine (D.M.P., J.S.P.), and Department of Psychiatry and Health Behavior (W.V.M.), Georgia Regents University, Augusta; Technology Applications Center for Healthful Lifestyles, Colleges of Nursing and Medicine, Medical University of South Carolina, Charleston (F.A.T.); and Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham (D.M.P., J.S.P.).
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Ozkor MA, Rahman AM, Murrow JR, Kavtaradze N, Lin J, Manatunga A, Hayek S, Quyyumi AA. Differences in vascular nitric oxide and endothelium-derived hyperpolarizing factor bioavailability in blacks and whites. Arterioscler Thromb Vasc Biol 2014; 34:1320-7. [PMID: 24675657 DOI: 10.1161/atvbaha.113.303136] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Abnormalities in nitric oxide (NO) bioavailability have been reported in blacks. Whether there are differences in endothelium-derived hyperpolarizing factor (EDHF) in addition to NO between blacks and whites and how these affect physiological vasodilation remain unknown. We hypothesized that the bioavailability of vascular NO and EDHF, at rest and with pharmacological and physiological vasodilation, varies between whites and blacks. APPROACH AND RESULTS In 74 white and 86 black subjects without known cardiovascular disease risk factors, forearm blood flow was measured using plethysmography at rest and during inhibition of NO with N(G)-monomethyl-L-arginine and of K(+) Ca channels (EDHF) with tetraethylammonium. The reduction in resting forearm blood flow was greater with N(G)-monomethyl-L-arginine (P=0.019) and similar with tetraethylammonium in whites compared with blacks. Vasodilation with bradykinin, acetylcholine, and sodium nitroprusside was lower in blacks compared with whites (all P<0.0001). Inhibition with N(G)-monomethyl-L-arginine was greater in whites compared with blacks with bradykinin, acetylcholine, and exercise. Inhibition with tetraethylammonium was lower in blacks with bradykinin, but greater during exercise and with acetylcholine. CONCLUSIONS The contribution to both resting and stimulus-mediated vasodilator tone of NO is greater in whites compared with blacks. EDHF partly compensates for the reduced NO release in exercise and acetylcholine-mediated vasodilation in blacks. Preserved EDHF but reduced NO bioavailability and sensitivity characterizes the vasculature in healthy blacks. CLINICAL TRIAL REGISTRATION URL http://clinicaltrials.gov/. Unique identifier: NCT00166166.
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Affiliation(s)
- Muhiddin A Ozkor
- From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (M.A.O., A.M.R., J.R.M., N.K., S.H., A.A.Q.); and Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA (J.L., A.M.)
| | - Ayaz M Rahman
- From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (M.A.O., A.M.R., J.R.M., N.K., S.H., A.A.Q.); and Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA (J.L., A.M.)
| | - Jonathan R Murrow
- From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (M.A.O., A.M.R., J.R.M., N.K., S.H., A.A.Q.); and Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA (J.L., A.M.)
| | - Nino Kavtaradze
- From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (M.A.O., A.M.R., J.R.M., N.K., S.H., A.A.Q.); and Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA (J.L., A.M.)
| | - Ji Lin
- From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (M.A.O., A.M.R., J.R.M., N.K., S.H., A.A.Q.); and Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA (J.L., A.M.)
| | - Amita Manatunga
- From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (M.A.O., A.M.R., J.R.M., N.K., S.H., A.A.Q.); and Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA (J.L., A.M.)
| | - Salim Hayek
- From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (M.A.O., A.M.R., J.R.M., N.K., S.H., A.A.Q.); and Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA (J.L., A.M.)
| | - Arshed A Quyyumi
- From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (M.A.O., A.M.R., J.R.M., N.K., S.H., A.A.Q.); and Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA (J.L., A.M.).
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Interactive influences of ethnicity, endothelin-1 gene, and everyday discrimination upon nocturnal ambulatory blood pressure. Ann Behav Med 2013; 45:377-86. [PMID: 23436272 DOI: 10.1007/s12160-013-9472-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND Everyday discrimination scale scores are associated with increased ambulatory blood pressure (BP) and reduced nocturnal dipping, and the endothelin-1 (ET-1)/Lys198Asn polymorphism is associated with increased resting BP and exaggerated BP reactivity among African Americans compared to European Americans. Combined influences of these factors on BP control are unknown. PURPOSE This study tested the hypothesis of a three-way interaction between ethnicity, ET-1 carrier status, and everyday discrimination upon ambulatory BP and nocturnal dipping. METHODS Baseline laboratory anthropometrics and the everyday discrimination scale were completed by 352 (175 African American) young adult normotensives, followed by 24-h ambulatory BP monitoring. RESULTS For nocturnal dipping, multiple regression models controlling for age, sex, ethnicity, and body mass index revealed significant three-way ET-1 × everyday discrimination × ethnicity interactions. Specifically, among African American ET-1 T-allele carriers, increases in everyday discrimination led to reduced nocturnal dipping. CONCLUSIONS African Americans that carry the ET-1/Lys198Asn T-allele and report higher everyday discrimination scores may be at particular risk for reduced nocturnal dipping.
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Shah AS, Dolan LM, Gao Z, Kimball TR, Urbina EM. Racial differences in arterial stiffness among adolescents and young adults with type 2 diabetes. Pediatr Diabetes 2012; 13:170-5. [PMID: 21790919 PMCID: PMC3210878 DOI: 10.1111/j.1399-5448.2011.00798.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND African-American adults demonstrate a higher prevalence of cardiovascular complications including myocardial infarction and stroke. Whether similar racial disparities are present to suggest African-Americans adolescents are at higher risk to develop cardiovascular disease is not known. Thus, we compared arterial stiffness, an early marker of cardiovascular disease, in African-American and Caucasian adolescents and young adults with type 2 diabetes. METHODS Demographic, anthropometric, laboratory data, and arterial stiffness measures including pulse wave velocity (PWV) and augmentation index (AIx) were collected in a cross-sectional study of 215 adolescents (average age 18 yr) with type 2 diabetes (55% African-American and 65% female). RESULTS Compared to Caucasians, African-Americans had increased PWV (6.21 ± 0.87 vs. 6.96 ± 1.30, p < .01) and AIx (4.44 ± 11.17 vs. 7.64 ± 12.02, p = 0.05). Regression modeling demonstrated age, lipids, blood pressure, and duration of diabetes were differently associated with arterial stiffness in each race group (p < 0.05). CONCLUSIONS African-American adolescents and young adults with type 2 diabetes have increased vascular stiffness than age-matched Caucasians. This process is mediated by different cardiovascular risk factors. These results suggest race-specific risk factor modification may be helpful to prevent early cardiovascular disease in this high risk population.
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Affiliation(s)
- Amy S Shah
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
| | - Lawrence M Dolan
- Cincinnati Children’s Hospital Medical Center, Division of Endocrinology. Cincinnati Ohio 45229
| | - Zhiqian Gao
- Cincinnati Children’s Hospital Medical Center, Division of Cardiology. Cincinnati Ohio 45229
| | - Thomas R Kimball
- Cincinnati Children’s Hospital Medical Center, Division of Cardiology. Cincinnati Ohio 45229
| | - Elaine M Urbina
- Cincinnati Children’s Hospital Medical Center, Division of Cardiology. Cincinnati Ohio 45229
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Hoffman RP. Effect of adolescent obesity on cardiometabolic risk in african-americans and Caucasians. ISRN OBESITY 2012; 2012:603205. [PMID: 24533206 PMCID: PMC3914275 DOI: 10.5402/2012/603205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 11/29/2012] [Indexed: 01/04/2023]
Abstract
African-Americans have more hypertension, stroke, and type 2 diabetes than do Caucasians. Endothelial dysfunction and insulin resistance are precursors for each. Since these diseases have origins in pediatrics and are associated with obesity, this study was designed to determine if obesity has different effects on endothelial function, insulin sensitivity, and secretion in African-American and Caucasian adolescents. Thirty-three Caucasian and 25 African-Americans (10–18 years old) were subdivided by BMI into lean, overweight, and obesity groups. Endothelial function was measured as forearm vascular resistance (FVR) over 1 min following 5 min of upper arm vascular occlusion. Insulin sensitivity and secretion were measured using intravenous glucose tolerance test and minimal model. Postocclusive FVR was significantly increased in obese African-Americans. Insulin sensitivity was reduced in obese subjects but did not differ by race. Insulin secretion was increased in African-Americans but did not differ by obesity. Subjects were subdivided into risk groups based on 20th percentile for postocclusion FVR response in lean. Seven of nine obese African-Americans were in the high risk group compared to 0 of 5 obese Caucasians. These results demonstrate that obesity significantly impairs endothelial function in African-Americans. Endothelial dysfunction likely predisposes to future cardiometabolic disease in obese African-American adolescents.
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Affiliation(s)
- Robert P Hoffman
- Division of Pediatric Endocrinology, Metabolism, and Diabetes, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
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Differential Impact of Stress Reduction Programs upon Ambulatory Blood Pressure among African American Adolescents: Influences of Endothelin-1 Gene and Chronic Stress Exposure. Int J Hypertens 2011; 2012:510291. [PMID: 22164329 PMCID: PMC3227499 DOI: 10.1155/2012/510291] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 08/17/2011] [Accepted: 09/06/2011] [Indexed: 11/17/2022] Open
Abstract
Stress-activated gene × environment interactions may contribute to individual variability in blood pressure reductions from behavioral interventions. We investigated effects of endothelin-1 (ET-1) LYS198ASN SNP and discriminatory stress exposure upon impact of 12-week behavioral interventions upon ambulatory BP (ABP) among 162 prehypertensive African American adolescents. Following genotyping, completion of questionnaire battery, and 24-hour ABP monitoring, participants were randomized to health education control (HEC), life skills training (LST), or breathing awareness meditation (BAM). Postintervention ABP was obtained. Significant three-way interactions on ABP changes indicated that among ET-1 SNP carriers, the only group to show reductions was BAM from low chronic stress environments. Among ET-1 SNP noncarriers, under low chronic stress exposure, all approaches worked, especially BAM. Among high stress exposure noncarriers, only BAM resulted in reductions. If these preliminary findings are replicated via ancillary analyses of archival databases and then via efficacy trials, selection of behavioral prescriptions for prehypertensives will be edging closer to being guided by individual's underlying genetic and environmental factors incorporating the healthcare model of personalized preventive medicine.
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Abstract
Since its discovery in 1988 as an endothelial cell-derived peptide that exerts the most potent vasoconstriction of any known endogenous compound, endothelin (ET) has emerged as an important regulator of renal physiology and pathophysiology. This review focuses on how the ET system impacts renal function in health; it is apparent that ET regulates multiple aspects of kidney function. These include modulation of glomerular filtration rate and renal blood flow, control of renin release, and regulation of transport of sodium, water, protons, and bicarbonate. These effects are exerted through ET interactions with almost every cell type in the kidney, including mesangial cells, podocytes, endothelium, vascular smooth muscle, every section of the nephron, and renal nerves. In addition, while not the subject of the current review, ET can also indirectly affect renal function through modulation of extrarenal systems, including the vasculature, nervous system, adrenal gland, circulating hormones, and the heart. As will become apparent, these pleiotropic effects of ET are of fundamental physiologic importance in the control of renal function in health. In addition, to help put these effects into perspective, we will also discuss, albeit to a relatively limited extent, how alterations in the ET system can contribute to hypertension and kidney disease.
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Affiliation(s)
- Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah, USA.
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Kohan DE, Rossi NF, Inscho EW, Pollock DM. Regulation of blood pressure and salt homeostasis by endothelin. Physiol Rev 2011; 91:1-77. [PMID: 21248162 DOI: 10.1152/physrev.00060.2009] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Endothelin (ET) peptides and their receptors are intimately involved in the physiological control of systemic blood pressure and body Na homeostasis, exerting these effects through alterations in a host of circulating and local factors. Hormonal systems affected by ET include natriuretic peptides, aldosterone, catecholamines, and angiotensin. ET also directly regulates cardiac output, central and peripheral nervous system activity, renal Na and water excretion, systemic vascular resistance, and venous capacitance. ET regulation of these systems is often complex, sometimes involving opposing actions depending on which receptor isoform is activated, which cells are affected, and what other prevailing factors exist. A detailed understanding of this system is important; disordered regulation of the ET system is strongly associated with hypertension and dysregulated extracellular fluid volume homeostasis. In addition, ET receptor antagonists are being increasingly used for the treatment of a variety of diseases; while demonstrating benefit, these agents also have adverse effects on fluid retention that may substantially limit their clinical utility. This review provides a detailed analysis of how the ET system is involved in the control of blood pressure and Na homeostasis, focusing primarily on physiological regulation with some discussion of the role of the ET system in hypertension.
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Affiliation(s)
- Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
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Clinical Characteristics, Vascular Function, and Inflammation in Women With Angina in the Absence of Coronary Atherosclerosis. JACC Cardiovasc Imaging 2011; 4:65-73. [DOI: 10.1016/j.jcmg.2010.10.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 08/11/2010] [Accepted: 10/12/2010] [Indexed: 11/22/2022]
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DeLoach S, Huan Y, Daskalakis C, Falkner B. Endothelin-1 response to glucose and insulin among African Americans. ACTA ACUST UNITED AC 2010; 4:227-35. [PMID: 20728421 DOI: 10.1016/j.jash.2010.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 07/07/2010] [Accepted: 07/31/2010] [Indexed: 11/15/2022]
Abstract
Endothelin-1 (ET-1) is implicated in the pathogenesis of hypertension. In vitro studies demonstrate that ET-1 is upregulated by insulin and glucose. The purpose of this study was to determine the effects of insulin and glucose on ET-1 levels in young adult African Americans, a population with a high burden of hypertension and diabetes. Plasma and urine ET-1 levels were measured before and after an oral glucose tolerance test (OGTT) and insulin clamp procedure in 288 participants. Subjects were classified according to glucose tolerance and blood pressure (BP) status. Plasma and urine ET-1 were not significantly different among the glucose tolerance groups. There was a trend toward increased plasma ET-1 among those with diabetes compared with impaired glucose tolerance and normal glucose tolerance; however, this was not statistically significant (P = .085). According to BP status, plasma ET-1 was highest among the high BP group compared with the normal BP group (P = .01). After glucose challenge, plasma ET-1 levels decreased and urine ET-1 increased in all three BP groups (P = .037). Our data show that plasma ET-1 is higher among young adult African Americans with hypertension compared with normotension. Urine ET-1 levels increased in response to glucose challenge, possibly indicating early renal injury.
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Affiliation(s)
- Stephanie DeLoach
- Department of Medicine, Thomas Jefferson University, Philadelphia, PA, USA
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Cooper DC, Mills PJ, Bardwell WA, Ziegler MG, Dimsdale JE. The effects of ethnic discrimination and socioeconomic status on endothelin-1 among blacks and whites. Am J Hypertens 2009; 22:698-704. [PMID: 19390511 DOI: 10.1038/ajh.2009.72] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Ethnic disparities in cardiovascular disease (CVD) may partially reflect differences in chronic stress burden that vary by social class and exposure to ethnic discrimination. Stress is associated with increased endothelin-1 (ET-1). This study examined the relationship of ET-1 to socioeconomic status (SES) and to perceived ethnic discrimination among black (n = 51) and white (n = 65) adults (mean age 36.5). METHODS The Perceived Discrimination subscale of the Scale of Ethnic Experience measured exposure to discrimination and the Hollingshead Two-Factor Index of Social Position assessed SES. Plasma ET-1 was sampled upon awakening after an overnight admission. RESULTS SES and ET-1 levels were similar across ethnic groups, but mean discrimination scores were higher among blacks than whites (P < 0.001). Multiple regressions found that the SES x ethnicity interaction was associated with ET-1 (P < 0.05), after adjustment for gender, resting mean arterial pressure (MAP), body mass index (BMI), and exercise frequency. Regressions stratified by ethnicity revealed that lower SES correlated with higher ET-1 in whites (P < 0.001), but not blacks, and accounted for 21% of the variance. Another series of regressions revealed an interaction effect of ethnicity by discrimination on ET-1 (P < 0.05). Increased discrimination correlated with increased ET-1 among blacks (P < 0.05), but not whites, and explained 11% of the variance after adjustment for SES, gender, exercise frequency, and socially desirable response bias. CONCLUSIONS Thus, ET-1 levels increased in association with different psychosocial burdens in blacks and whites. Plasma ET-1 was higher among whites with lower SES and among blacks with higher levels of perceived ethnic discrimination, regardless of SES.
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Endothelial dysfunction in African-Americans. Int J Cardiol 2008; 132:157-72. [PMID: 19004510 DOI: 10.1016/j.ijcard.2008.10.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2008] [Revised: 07/25/2008] [Accepted: 10/12/2008] [Indexed: 01/13/2023]
Abstract
The journey of atherosclerosis begins with endothelial dysfunction and culminates into its most fearful destination producing ischemia, myocardial infarction and death. The excess cardiovascular disease morbidity and mortality in African-Americans is one of the major public health problems. In this review, we discuss vascular endothelial dysfunction as a key element for excess cardiovascular disease burden in this target population. It can be logical window of future atherosclerotic outcomes, and further efforts should be made to detect it at the earliest in African American individuals even if they are appearing healthy as the therapeutic interventions if instituted early, might prevent the subsequent cardiac events.
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Abstract
Endothelins are powerful vasoconstrictor peptides that also play numerous other roles. The endothelin (ET) family consists of three peptides produced by a variety of tissues. Endothelin-1 (ET-1) is the principal isoform produced by the endothelium in the human cardiovascular system, and it exerts its actions through binding to specific receptors, the so-called type A (ET(A)) and type B (ET(B)) receptors. ET-1 is primarily a locally acting paracrine substance that appears to contribute to the maintenance of basal vascular tone. It is also activated in several diseases, including congestive heart failure, arterial hypertension, atherosclerosis, endothelial dysfunction, coronary artery diseases, renal failure, cerebrovascular disease, pulmonary arterial hypertension, and sepsis. Thus, ET-1 antagonists are promising new agents. They have been shown to be effective in the management of primary pulmonary hypertension, but disappointing in heart failure. Clinical trials are needed to determine whether manipulation of the ET system will be beneficial in other diseases.
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Affiliation(s)
- Rahman Shah
- Section of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
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Yoshida Y, Hachiya A, Sriwiriyanont P, Ohuchi A, Kitahara T, Takema Y, Visscher MO, Boissy RE. Functional analysis of keratinocytes in skin color using a human skin substitute model composed of cells derived from different skin pigmentation types. FASEB J 2007; 21:2829-39. [PMID: 17475923 DOI: 10.1096/fj.06-6845com] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Skin color is one of the most distinct features in the human race. To assess the mechanisms of skin color variation, human skin substitutes (HSS) were constructed by grafting mixtures of cultured keratinocytes and melanocytes from a combination of donor skin types, together with light skin derived fibroblasts, into chambers inserted onto the back skin of severe combined immunodeficient (SCID) mice. The resulting complexion coloration of the HSS was relatively darker and lighter when dark and light skin derived keratinocytes, respectively, were combined with melanocytes derived from either light or dark skin. The melanin content in the epidermis and the maturation stage of melanosomes in basal keratinocytes were significantly increased in the HSS composed of dark compared to light skin derived keratinocytes. In addition, the ratio of individual/clustered melanosomes in recipient keratinocytes was increased in the former as opposed to the latter HSS. The genetic expression of endothelin-1, proopiomelanocortin, microphthalmia-associated transcription factor, tyrosinase, GP100, and MART1 were increased in HSS composed of dark vs. light skin derived keratinocytes. These data suggest that our HSS is a promising melanogenic model that demonstrates the role of the keratinocyte in regulating in part both melanogenesis and distribution of transferred melanosomes.
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Affiliation(s)
- Yasuko Yoshida
- Kao Biological Science Laboratories, Haga, Tochigi, Japan
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Duck MM, Hoffman RP. Impaired endothelial function in healthy African-American adolescents compared with Caucasians. J Pediatr 2007; 150:400-6. [PMID: 17382119 PMCID: PMC1894939 DOI: 10.1016/j.jpeds.2006.12.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 10/16/2006] [Accepted: 12/11/2006] [Indexed: 01/04/2023]
Abstract
OBJECTIVE To determine whether African-American adolescents have endothelial dysfunction compared with Caucasians and whether differences are a result of differences in insulin sensitivity calculated from total glucose (S(I)) or secretion. STUDY DESIGN Thirty-three Caucasian (13.6 +/- 2.6 years of age; body mass index [BMI] 21.6 +/- 4.4 kg/m2 mean +/- SD) and 25 African-American (13.3 +/- 2.9 years of age; BMI 24.0 +/- 4.4 kg/m2) adolescents were studied. Forearm blood flow (FBF; plethysmography) was measured before and after 5 minutes of arterial occlusion. S(I) and acute insulin response to glucose (AIRG) were measured using intravenous glucose tolerance tests and minimal modeling. RESULTS Baseline FBF did not differ between races. Postocclusion FBF was lower in African-Americans (17.2 +/- 1.2 vs 22.6 +/- 1.2 mL/dL/minute, P = .006). AIRG was higher in African-Americans (6050 +/- 940 vs 2410 +/- 30 microU minute/mL, P = .001). Pubertal stage had no effect. S(I) did not differ by race or pubertal stage. In African-Americans, percent fall in FVR following arterial occlusion correlated (r = 0.67, P = .001) with log AIRG. No relationships were found between percent fall in FVR and S(I) in either race. CONCLUSION African-American adolescents have decreased endothelial function. This may be a result of increased insulin secretion. Endothelial dysfunction in African-American adolescents may predispose to cardiovascular and type II diabetes.
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Affiliation(s)
- Mary M. Duck
- University of Cincinnati College of Medicine, the Ohio State University College of Medicine and Public Health And the Children’s Research Institute, Columbus, Ohio
| | - Robert P. Hoffman
- Division of Pediatric Endocrinology Department of Pediatrics, and the Clinical Research Center of The Ohio State University College of Medicine and Public Health And the Children’s Research Institute, Columbus, Ohio
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Kanaya AM, Barrett-Connor E, Wassel Fyr CL. Endothelin-1 and prevalent coronary heart disease in older men and women (the Rancho Bernardo Study). Am J Cardiol 2007; 99:486-90. [PMID: 17293190 PMCID: PMC3947589 DOI: 10.1016/j.amjcard.2006.09.096] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 09/13/2006] [Accepted: 09/13/2006] [Indexed: 01/09/2023]
Abstract
Endothelin-1 has been implicated in atherosclerotic and ischemic heart disease. No population-based studies have examined the association of endothelin-1 with coronary heart disease (CHD). We performed a cross-sectional analysis of 961 older women and men. CHD was defined as a history of myocardial infarction, coronary surgery, angina, or major Q-wave abnormality on electrocardiography. We examined the association of endothelin-1 with CHD after adjusting for known risk factors and atherosclerosis measures. A total of 248 women and 156 men had CHD. Median endothelin-1 levels were similar by gender and higher among those with versus those without CHD (3.3 vs 3.1 pg/ml, p <0.001). After adjusting for age, smoking, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, hypertension, diabetes, alcohol use, exercise, aspirin, cholesterol-lowering medication, and hormone therapy use, endothelin-1 had a stronger association with CHD in women (odds ratio [OR] 3.02, (95% confidence interval 1.43 to 6.37) than in men (OR 1.82, 95% confidence interval 0.74 to 4.51). Age modified the effect of endothelin-1 with CHD in men (OR 0.47 for age <75 years vs 3.84 in men >or=75 years, p = 0.05 for interaction). Further adjustment for ankle-brachial index and carotid intima media thickness did not alter these results. In conclusion, higher endothelin-1 levels are independently associated with CHD in women of all ages and among older men only.
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Affiliation(s)
- Alka M Kanaya
- Division of General Internal Medicine, University of California-San Francisco, San Francisco, California, USA.
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35
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Flack JM, Shafi T, Chandra S, Ramos J, Nasser SA, Crook ED. Hypertension in African Americans. Hypertension 2007. [DOI: 10.1016/b978-1-4160-3053-9.50045-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Obineche E, Abdulle AM, Bokhari AM, Yasin JY, Gillett MPT. Circulating levels of endothelin-1 in a homogenous Gulf Arab population with untreated essential hypertension. Ann Saudi Med 2006; 26:364-9. [PMID: 17019099 PMCID: PMC6074109 DOI: 10.5144/0256-4947.2006.364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Racial variations are reported in the natural history of hypertension. For example, hypertension is significantly more prevalent in blacks than whites. Endothelial cells are important regulators of vascular tone and homeostasis, in part through secretions of vasoactive substances including endothelin-1 (ET-1), a small peptide with potent vasopressor actions. In black hypertensives, ET-1 levels are higher than in normotensive blacks and in both hypertensive and normotensive whites. Since ET-1 might play a significant role in the development and severity of hypertension in the indigenous Arab population of the United Arab Emirates, we investigated the circulating levels of ET-1 in this homogenous population. PATIENTS AND METHODS ET-1 levels were measured in plasma samples from 60 untreated hypertensive Arabs and compared with 60 age- and sex-matched normotensive controls. RESULTS ET-1 levels were significantly higher in hypertensives (mean 10.1 +/- 1 pmol/L) than normotensives (mean 2.2 +/- 0.5 pmol/L). Body mass index (BMI) was slightly higher among the hypertensives. For all subjects these levels significantly (P < 0.001) correlated with systolic blood pressure and less significantly (P < 0.05) with diastolic blood pressure and body weight. The correlation between ET-1 and both systolic and diastolic blood pressure was persistently significant after adjusting for BMI. CONCLUSION Plasma concentrations of ET-1 are significantly higher in hypertensive Gulf Arabs as compared with reported levels in white hypertensives and ET-1 could be a risk factor for cardiovascular diseases in this population. The endothelial system might be particularly important with respect to hypertension in this racial group and merits further study.
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Affiliation(s)
- Enyioma Obineche
- Department of Internal Medicine, Faculty of Medicine & Health Sciences, UAE University, Al Ain, Abu Dhabi, United Arab Emirates.
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Tharaux PL, Hagège I, Placier S, Vayssairat M, Kanfer A, Girot R, Dussaule JC. Urinary endothelin-1 as a marker of renal damage in sickle cell disease. Nephrol Dial Transplant 2005; 20:2408-13. [PMID: 16144850 DOI: 10.1093/ndt/gfi111] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Sickle cell disease (SCD) affects the kidney by acute mechanisms as well as by insidious renal medullary/papillary necrosis, resulting in tubular defects, which increase the risk of dehydration and subsequent sickle crisis. Hypoxia has been reported to stimulate endothelin-1 (ET-1) synthesis by endothelial cells and also in the renal tubule. METHODS This case-control study measured ET-1 in urine as a marker of its renal synthesis in asymptomatic SCD patients. Baseline plasma and urinary ET-1 levels were measured and followed during a water deprivation study and a subsequent administration of desmopressin. RESULTS Urine and plasma levels of ET-1 were elevated in patients with SCD, compared with carefully matched African-French and African controls, and urine ET-1 excretion was associated with a marked urine-concentrating defect. Moreover, urinary ET-1 output was correlated with microalbuminuria in SCD patients. CONCLUSIONS ET-1 is known to antagonize the tubular effects of vasopressin and to promote renal scarring; increased renal production of ET-1 could produce nephrogenic diabetes insipidus and dehydration in SCD patients through a combination of fibrosis and functional resistance to vasopressin. This study provides a rationale for trials with endothelin receptor antagonists in sickle cell disease nephropathy.
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Rabineau KM, Treiber FA, Poole J, Ludwig D. Interactive effects of anger expression and ET-1 Lys198Asn polymorphism on vasoconstriction reactivity to behavioral stress. Ann Behav Med 2005; 30:85-9. [PMID: 16097909 DOI: 10.1207/s15324796abm3001_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Ineffective anger expression has been associated with essential hypertension (EH) and with blood pressure (BP) reactivity to stress. The ET-1/Lys198Asn polymorphism has been associated with increased resting BP and exaggerated vasoconstrictive mediated BP reactivity. African Americans (AAs) are at particular risk for development of EH, report greater anger difficulties, and exhibit greater vasoconstrictive reactivity than their European American (EA) counterparts. PURPOSE The objective is to investigate a gene-environment model of stress reactivity in which anger expression, particularly in combination with ET-1 T allele carrier status and AA ethnicity, would be associated with the greatest vasoconstrictive reactivity in response to a behavioral stressor. METHODS One hundred ninety-one AA and 197 EA normotensive young adults (M age=18.8+/-2.5 years) participated in the study. Total peripheral resistance index (TPRI) reactivity was assessed during a 10-min video game challenge. Anger expression was measured using Spielberger's Anger Expression Scale. RESULTS A multiple regression model with TPRI reactivity as the dependent variable revealed a three-way interaction effect for anger management (i.e., AM=anger control minus anger out scores), ethnicity, and ET-1 polymorphism. Specifically, AA carriers of the ET-1 polymorphism with poor AM skills exhibited the greatest TPRI reactivity. CONCLUSIONS Individuals with a genetic predisposition for exaggerated vasoconstriction who also display low AM skills may be at particular risk for development of stress-induced EH. Such individuals may particularly benefit from anger management training.
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Affiliation(s)
- Kristen M Rabineau
- Department of Psychiatry, Medical College of Georgia, Georgia Prevention Institute, Augusta 30912, USA
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Sosin MD, Bhatia GS, Davis RC, Lip GYH. Heart failure-the importance of ethnicity. Eur J Heart Fail 2004; 6:831-43. [PMID: 15556044 DOI: 10.1016/j.ejheart.2003.11.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2003] [Revised: 10/31/2003] [Accepted: 11/06/2003] [Indexed: 11/20/2022] Open
Abstract
Heart failure is a major public health problem in the Western world. Aetiological factors involved in its development include hypertension, diabetes, and ischaemic heart disease--all of which differ in prevalence, and possibly mechanism, between patients of differing ethnicity. Unfortunately, epidemiological and therapeutic trials have involved almost exclusively white populations, and evidence from these trials cannot necessarily be assumed to be generalisable to populations that include high proportions of patients from other ethnic origins. This review will discuss the mechanistic and therapeutic differences that exist in heart failure between those of European origin, and patients from the major ethnic minority groups of the UK.
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Affiliation(s)
- Michael D Sosin
- University Department of Medicine, Sandwell and West Birmingham Hospitals NHS Trust, City Hospital, Birmingham B18 7QH, England, UK
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Xiang S, Denver R, Bailey M, Krum H. Physiologic determinants of endothelin concentrations in human saliva. Clin Chem 2003; 49:2012-9. [PMID: 14633872 DOI: 10.1373/clinchem.2003.020875] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Salivary endothelin (ET) concentrations have been shown to correlate with disease severity in patients with chronic heart failure (CHF). We undertook the present study to evaluate the stability of salivary ET under different handling conditions to assess its suitability as a biochemical marker in screening, diagnosis, and management of CHF. METHODS Saliva samples were collected from healthy individuals and/or CHF patients, subjected to different handling conditions, and then stored at -80 degrees C until assayed by an ELISA for ET. RESULTS Salivary ET concentrations showed a time-dependent increase during storage at room temperature. After 72 h of incubation at room temperature, ET increased approximately 2.8-fold (P = 0.03). Simultaneously, salivary big ET showed a time-dependent 11.2-fold decrease (P <0.0001). This activity was blocked by an ET-converting enzyme (ECE) inhibitor, suggesting that these changes were attributable to ECE-dependent cleavage of endogenous big ET in saliva. Ex vivo conversion was also observed when samples were stored at 4 degrees C, but the magnitude of these changes was markedly smaller (P <0.0001). Posture also affected salivary ET concentrations in CHF patients. With a change from supine to seated rest, salivary ET concentrations increased 1.5- and 1.8-fold after 20 and 40 min, respectively (P = 0.01). With a return to supine rest, salivary ET concentrations returned to baseline concentrations (P = 0.008). CONCLUSIONS These data suggest that saliva sampling and handling conditions could markedly affect measurement of salivary ET. In particular, care should be taken to minimize ECE-dependent enzymatic conversion of endogenous big ET in saliva.
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Affiliation(s)
- Sue Xiang
- Department of Medicine and Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, Victoria 3004, Australia
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Schaefer BM, Caracciolo V, Frishman WH, Charney P. Gender, ethnicity and genetics in cardiovascular disease: part 1: Basic principles. HEART DISEASE (HAGERSTOWN, MD.) 2003; 5:129-43. [PMID: 12713680 DOI: 10.1097/01.hdx.0000061694.62343.01] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Prior to 1993, most drug efficacy and safety trials were conducted in white males, although gender and racial differences in pharmacodynamics and pharmacokinetics have been documented since the early 1900s. Over the last 2 decades, supported by the FDA and legislation, attempts to include more women and minorities in clinical drug trials have been made, with limited success. Yet, there are important differences in pathophysiology and pharmacogenetics, as well as pharmacotherapeutic effectiveness. This is the first of 2 articles that review the basic scientific principles of such differences. In particular, genetic polymorphisms of cardiovascular candidate genes and drug metabolism are described. The pharmacodynamic and pharmacokinetic variations among genders and ethnicities are summarized.
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Abstract
Hypertension and diabetes mellitus are the leading contributors to end-stage renal disease. African Americans suffer higher rates of renal failure as well as other vascular morbidities associated with hypertension and diabetes. Insulin resistance is strongly associated with hypertension. Insulin resistance is a component of diabetes and also precedes the clinical expression of type 2 diabetes. The relationship of blood pressure with insulin resistance, or impaired insulin action, occurs in African Americans and can be detected at young ages prior to the clinical expression of hypertension or diabetes. Through its relationship with hypertension, diabetes, and hyperlipidemia, insulin resistance is associated with endothelial dysfunction. The interface of insulin resistance with endothelial dysfunction may begin to explain the role of insulin resistance in vascular and renal pathology. The injury process, subsequent to both hypertension and diabetes, appears to be mediated by alterations tissue regulatory factors, and include vasoactive peptides such as angiotensin II, endothelin, and growth factors. Understanding the determinants that up-regulate the aberrant pathways and the early phases of these processes will be necessary to formulate strategies to effectively achieve renal protection and reduce the rates of renal failure in African Americans.
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Affiliation(s)
- Bonita Falkner
- Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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Alaluf S, Barrett K, Blount M, Carter N. Ethnic variation in tyrosinase and TYRP1 expression in photoexposed and photoprotected human skin. PIGMENT CELL RESEARCH 2003; 16:35-42. [PMID: 12519123 DOI: 10.1034/j.1600-0749.2003.00005.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The relative expression of a number of key mediators of human pigmentation including tyrosinase, tyrosinase related protein-1 (TYRP1), endothelin-1 and adrenocorticotrophic hormone (ACTH) proteins were analysed and quantified in immunohistochemically stained skin sections using semiquantitative computer assisted image analysis. Comparisons were made between a range of different ethnic skin types including European, Chinese, Mexican, Indian and African at both chronically photoexposed and photoprotected sites. Melanocyte number varied little with ethnicity except in the European group which had 60-80% more melanocytes than other skin types (P < 0.01, n = 10; Student Neuman-Keuls). However, melanocyte number was increased approximately twofold in chronically photoexposed skin of all ethnic groups (P < 0.001, n = 48; paired t-test). Tyrosinase protein expression in melanocytes did not vary with ethnicity, but TYRP1 protein was significantly elevated (approximately 2.6-fold) in darkly pigmented African and Indian skin types compared with lightly pigmented Mexican, Chinese and European skin types. In melanocytes from chronically photoexposed skin, there was a modest but significant increase in the expression of tyrosinase protein (approximately 1.2-fold, P < 0.001, n = 48; paired t-test), together with a significant and slightly larger increase in the expression of TYRP1 protein (approximately 1.6-fold, P < 0.005, n = 48; paired t-test). In contrast, the expression of endothelin-1 and ACTH showed no significant variation with either ethnicity or photoexposure. These data are consistent with the view that maintenance of a chronically hyperpigmented phenotype in chronically photoexposed human skin is largely the result of a stable increase in the number of tyrosinase positive melanocytes at these sites. Moreover, the observed ethnic variation in TYRP1 protein expression suggests that TYRP1 may play a significant role in mediating ethnic differences in melanogenesis and constitutive skin pigmentation in vivo.
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Affiliation(s)
- Simon Alaluf
- Unilever Research, Colworth Laboratory, Sharnbrook, Bedford, UK.
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Remuzzi G, Perico N, Benigni A. New therapeutics that antagonize endothelin: promises and frustrations. Nat Rev Drug Discov 2002; 1:986-1001. [PMID: 12461520 DOI: 10.1038/nrd962] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The discovery of endothelin--a highly potent endogenous vasoconstrictor - in 1988 has led to considerable efforts to develop antagonists of endothelin receptors that could have therapeutic potential in disorders including hypertension, heart failure and renal diseases. However, in general, the results of trials in humans have not mirrored the highly promising effects in animal disease models. Here, we discuss preclinical and clinical results with endothelin antagonists, and consider possible approaches to fully realizing the potential of endothelin antagonism.
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Affiliation(s)
- Giuseppe Remuzzi
- Mario Negri Institute for Pharmacological Research, Via Gavazzeni 11, 24125 Bergamo, Italy.
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Abstract
The purpose of the present study was to determine sympathetic vascular transduction in young normotensive black and white adults. We hypothesized that blacks would demonstrate augmented transduction of muscle sympathetic nerve activity (MSNA) into vascular resistance. To test this hypothesis, MSNA, forearm blood flow, heart rate, and arterial blood pressure were measured during lower body negative pressure (LBNP). At rest, no differences existed in arterial blood pressure, heart rate, forearm blood flow, and forearm vascular resistance (FVR). Likewise, LBNP elicited comparable responses of these variables for blacks and whites. Baseline MSNA did not differ between blacks and whites, but whites demonstrated greater increases during LBNP (28 +/- 7 vs. 55 +/- 18%, 81 +/- 21 vs. 137 +/- 42%, 174 +/- 81 vs. 556 +/- 98% for -5, -15, and -40 mmHg LBNP, respectively; P < 0.001). Consistent with smaller increases in MSNA but similar FVR responses during LBNP, blacks demonstrated greater sympathetic vascular transduction (%FVR/%MSNA) than whites (0.95 +/- 0.07 vs. 0.82 +/- 0.07 U; 0.82 +/- 0.11 vs. 0.64 +/- 0.09 U; 0.95 +/- 0.37 vs. 0.35 +/- 0.09 U; P < 0.01). In summary, young whites demonstrate greater increases in MSNA during baroreceptor unloading than age-matched normotensive blacks. However, more importantly, for a given increase in MSNA, blacks demonstrate greater forearm vasoconstriction than whites. This finding may contribute to augmented blood pressure reactivity in blacks.
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Affiliation(s)
- Chester A Ray
- Department of Medicine (Cardiology), General Clinical Research Center, Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA.
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Okada M, Nishino M, Saito M, Ikeda T, Uehara S, Okada H, Niiyama K, Ohtake N, Hayama T, Nishikibe M. Marked reduction of mortality in salt-loaded Dahl salt-sensitive rats by the new, selective endothelin ETA receptor antagonist, J-105859. J Hypertens 2000; 18:1815-23. [PMID: 11132606 DOI: 10.1097/00004872-200018120-00016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To examine the chronic effects of a newly synthesized, potent and selective endothelin (ET) ETA receptor antagonist, J-1 05859, on mortality in salt-loaded Dahl salt-sensitive (DS) rats and to confirm the potential of this compound as an ETA antagonist METHODS Vehicle and J-105859 were administered to salt-loaded DS rats for 12 weeks. Throughout the experimental period, blood pressure was measured continuously using a telemetry system and the survival rate was determined. The surviving animals were subsequently sacrificed and autopsy was performed. Binding and functional assays were also carried out to characterize J-1 05859. RESULTS The Ki values of J-1 05859 for cloned human ETA and ETB were 0.025 and 48 nmol/l, respectively. J-105859 inhibited ET-1-induced contractions in rabbit iliac artery (pA2 = 10.08) and BQ-3020 (ETB agonist)-induced contractions in pulmonary artery (pA2 = 7.63). The pressor response to intravenous (i.v.) ET-1 (0.5 nmol/kg) was significantly inhibited by J-1 05859 at a dose of 0.03 mg/kg i.v. Chronic treatment with J-1 05859 [0.1 and 1 mg/kg per day orally (p.o.)] from the prehypertensive stage decreased the mortality of salt-loaded DS rats and markedly inhibited the development of brain lesions. The survival rates in the control and J-1 05859 (0.1 and 1 mg/kg per day) groups were 34, 80 and 100%, respectively. Development of hypertension was markedly inhibited at a dose of 1 mg/kg per day. CONCLUSION J-105859 is a selective, potent, orally active ETA-selective antagonist ETA antagonists may reduce morbidity as well as mortality in salt-sensitive hypertension.
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Affiliation(s)
- M Okada
- Tsukuba Research Institute, Banyu Pharmaceutical Co. Ltd, Ibaraki, Japan
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Lüscher TF, Barton M. Endothelins and endothelin receptor antagonists: therapeutic considerations for a novel class of cardiovascular drugs. Circulation 2000; 102:2434-40. [PMID: 11067800 DOI: 10.1161/01.cir.102.19.2434] [Citation(s) in RCA: 377] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The 21-amino acid peptide endothelin-1 (ET-1) is the predominant isoform of the endothelin peptide family, which includes ET-2, ET-3, and ET-4. It exerts various biological effects, including vasoconstriction and the stimulation of cell proliferation in tissues both within and outside of the cardiovascular system. ET-1 is synthesized by endothelin-converting enzymes (ECE), chymases, and non-ECE metalloproteases; it is regulated in an autocrine fashion in vascular and nonvascular cells. ET-1 acts through the activation of G(i)-protein-coupled receptors. ET(A) receptors mediate vasoconstriction and cell proliferation, whereas ET(B) receptors are important for the clearance of ET-1, endothelial cell survival, the release of nitric oxide and prostacyclin, and the inhibition of ECE-1. ET is activated in hypertension, atherosclerosis, restenosis, heart failure, idiopathic cardiomyopathy, and renal failure. Tissue concentrations more reliably reflect the activation of the ET system because increased vascular ET-1 levels occur in the absence of changes in plasma. Experimental studies using molecular and pharmacological inhibition of the ET system and the first clinical trials have demonstrated that ET-1 takes part in normal cardiovascular homeostasis. Thus, ET-1 plays a major role in the functional and structural changes observed in arterial and pulmonary hypertension, glomerulosclerosis, atherosclerosis, and heart failure, mainly through pressure-independent mechanisms. ET antagonists are promising new agents in the treatment of cardiovascular diseases.
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Affiliation(s)
- T F Lüscher
- Department of Cardiology, University Hospital Zürich, University of Zürich, Switzerland
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Ergul A. Hypertension in black patients: an emerging role of the endothelin system in salt-sensitive hypertension. Hypertension 2000; 36:62-7. [PMID: 10904013 DOI: 10.1161/01.hyp.36.1.62] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The prevalence of essential hypertension in blacks is much higher than that in whites. In addition, the pathogenesis of hypertension appears to be different in black patients. For example, black patients present with a salt-sensitive hypertension characterized by low renin levels. Racial differences in renal physiology and socioeconomic factors have been suggested as possible causes of this difference, but reasons for this difference remain unclear. Endothelial cells are important in the regulation of vascular tonus and homeostasis, in part through the secretion of vasoactive substances. One of these factors, endothelin-1 (ET-1), is a 21 amino acid residue peptide with potent vasopressor actions. In addition to its contractile effects, it has been shown to stimulate mitogenesis in a number of cell types. Moreover, ET-1 displays modulatory effects on the endocrine system, including stimulation of angiotensin II and aldosterone production and inhibition of antidiuretic hormone in the kidney. Recent data from several laboratories indicate that ET-1 is overexpressed in the vasculature in several salt-sensitive models of experimental hypertension. Moreover, circulating plasma ET-1 levels are significantly increased in black hypertensives compared with white hypertensives. Thus, the ET system might be particularly important in the development or maintenance of hypertension in this population.
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Affiliation(s)
- A Ergul
- Department of Surgery, Medical University of South Carolina, Charleston 29425, USA.
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Marks DS, Mensah GA, Kennard ED, Detre K, Holmes DR. Race, baseline characteristics, and clinical outcomes after coronary intervention: The New Approaches in Coronary Interventions (NACI) registry. Am Heart J 2000; 140:162-9. [PMID: 10874280 DOI: 10.1067/mhj.2000.106645] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND The impact of race and sex on clinical outcomes after percutaneous coronary interventions remains incompletely understood. Specific data on patient demographics, lesion characteristics, and outcomes of black versus white patients are poorly described. To further evaluate these issues, we analyzed the New Approaches in Coronary Interventions (NACI) registry. METHODS Patients (200 black, 4279 white) undergoing coronary interventions in the NACI trial were compared. A Cox proportional hazards model was used to determine which baseline demographics were independent risk factors for the combined end point of death, Q-wave myocardial infarction, and coronary artery bypass grafting at 1 year. RESULTS Black patients were significantly younger (age 59 +/- 11 vs 63 +/- 11 years; P <.001), more often obese (29.6 +/- 6 vs 27.5 +/- 4.8 kg/m(2); P <.001), female (50% vs 34%; P <.001), diabetic (34% vs 21%; P <.001), and hypertensive (71% vs 52%; P <.001). Black patients were significantly more likely to have single-vessel disease (48% vs 40%; P <.05) and less likely to have undergone coronary artery bypass grafting (26% vs 34%; P <.05). Blacks were significantly more likely to have a discrete lesion (85% vs 62%; P <. 001) with less thrombus (7% vs 12%; P <.05), tortuosity (17% vs 25%; P <.05), and an ulcerated appearance (5% vs 10%; P <.05). Despite these significant baseline differences, no significant difference was seen in the procedural success (80% vs 82%) or major adverse events (death, Q-wave myocardial infarction, any revascularization) at 1 year (39% vs 34%). Predictors of adverse events for white patients included diabetes (relative risk [RR] = 1.24; confidence intervals [CI], 1.0-1.5) and high-risk status (RR = 1.58; CI, 1.26-1. 91). Predictive characteristics of adverse events for black patients included only sex (RR = 3.45; CI, 1.27-9.35; P =.02). CONCLUSIONS There are significant differences in baseline characteristics of black patients compared with white patients. Despite these differences in traditional risk factors, they do not affect procedural success or 1-year outcome. In black patients, only sex predicted adverse events. Additional investigation is required to understand the mechanisms for this difference.
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Affiliation(s)
- D S Marks
- Adult Cardiac Catheterization Lab and Section of Cardiology, Medical College of Georgia, Augusta 30912-3105, USA.
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Treiber FA, Jackson RW, Davis H, Pollock JS, Kapuku G, Mensah GA, Pollock DM. Racial differences in endothelin-1 at rest and in response to acute stress in adolescent males. Hypertension 2000; 35:722-5. [PMID: 10720585 DOI: 10.1161/01.hyp.35.3.722] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Blacks exhibit greater vasoconstriction-mediated blood pressure (BP) increases in response to stress than do whites. Endothelin-1 (ET-1), a potent vasoconstrictive peptide, has been proposed as having a role in racial differences in stress reactivity. We evaluated the hemodynamic and plasma ET-1 levels of 41 (23 whites, 18 blacks, mean age 18.6 years) normotensive adolescent males at rest and in response to a video game challenge and forehead cold stimulation. Measurements were performed at catheter insertion and before and immediately after the 2 stressors, which were separated by 20-minute rest periods. Blacks exhibited higher absolute levels of diastolic blood pressure, total peripheral resistance index, or both in response to catheter insertion and to the video game challenge and during recovery from video game challenge and cold stimulation (P<0. 05 for all). Blacks exhibited higher absolute levels of ET-1 at every evaluation point (P<0.05 for all) and greater increases in ET-1 in response to both stressors (ps<0.05). These findings suggest that altered endothelial function may be involved in racial differences in hemodynamic reactivity to stress and possibly in the development of essential hypertension.
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Affiliation(s)
- F A Treiber
- Georgia Prevention Institute, the Vascular Biology Center, Departments of Pediatrics and Psychiatry , and Office of Biostatistics, Medical College of Georgia, Augusta, GA 30912-3710, USA.
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