Chenyi Ling

Endothelial activation microparticles and inflammation status improve with exercise training in African Americans

African Americans have the highest prevalence of hypertension in the world which may emanate from their predisposition to heightened endothelial inflammation. The purpose of this study was to determine the effects of a 6-month aerobic exercise training (AEXT) intervention on the inflammatory biomarkers interleukin-10 (IL-10), interleukin-6 (IL-6), and endothelial microparticle (EMP) CD62E+ and endothelial function assessed by flow-mediated dilation (FMD) in African Americans. A secondary purpose was to evaluate whether changes in IL-10, IL-6, or CD62E+ EMPs predicted the change in FMD following the 6-month AEXT intervention. A pre-post design was employed with baseline evaluation including office blood pressure, FMD, fasting blood sampling, and graded exercise testing. Participants engaged in 6 months of AEXT. Following the AEXT intervention, all baseline tests were repeated. FMD significantly increased, CD62E+ EMPs and IL-6 significantly decreased, and IL-10 increased but not significantly following AEXT. Changes in inflammatory biomarkers did not significantly predict the change in FMD. The change in VO2 max significantly predicted the change in IL-10. Based on these results, AEXT may be a viable, nonpharmacological method to improve inflammation status and endothelial function and thereby contribute to risk reduction for cardiovascular disease in African Americans.

Visit-to-visit and 24-h blood pressure variability: association with endothelial and smooth muscle function in African Americans

The purpose of this study was to investigate the association of visit-to-visit and 24-h blood pressure (BP) variability with markers of endothelial injury and vascular function. We recruited 72 African Americans who were non-diabetic, non-smoking and free of cardiovascular (CV) and renal disease. Office BP was measured at three visits and 24-h ambulatory BP monitoring was conducted to measure visit-to-visit and 24-h BP variability, respectively. The 5-min time-course of brachial artery flow-mediated dilation and nitroglycerin-mediated dilation were assessed as measures of endothelial and smooth muscle function. Fasted blood samples were analyzed for circulating endothelial microparticles (EMPs). Significantly lower CD31+CD42− EMPs were found in participants with high visit-to-visit systolic blood pressure (SBP) variability or high 24-h diastolic blood pressure (DBP) variability. Participants with high visit-to-visit DBP variability had significantly lower flow-mediated dilation and higher nitroglycerin-mediated dilation at multiple time-points. When analyzed as continuous variables, 24-h mean arterial pressure variability was inversely associated with CD62+ EMPs; visit-to-visit DBP variability was inversely associated with flow-mediated dilation normalized by smooth muscle function and was positively associated with nitroglycerin-mediated dilation; and 24-h DBP variability was positively associated with nitroglycerin-mediated dilation. All associations were independent of age, gender, body mass index and mean BP. In conclusion, in this cohort of African Americans visit-to-visit and 24-h BP variability were associated with measures of endothelial injury, endothelial function and smooth muscle function. These results suggest that BP variability may influence the pathogenesis of CV disease, in part, through influences on vascular health.

Effects of Moderate Aerobic Exercise Training on Vascular Health and Blood Pressure in African Americans

As healthcare progresses toward individualized medicine, understanding how different racial groups respond to lifestyle interventions is valuable. It is established that African Americans have disproportionate levels of cardiovascular disease and impaired vascular health, and clinical practice guidelines suggest lifestyle interventions as the first line of treatment. Recently, the authors reported that 6 months of aerobic exercise improved inflammatory markers, flow‐mediated dilation (FMD), and levels of circulating endothelial microparticles (EMPs) in African American adults. This study is a subgroup analysis of the aerobic exercise–induced changes in vascular health and blood pressure (BP) measures, including carotid artery intima‐media thickness (IMT), nitroglycerin‐mediated dilation (NMD), ambulatory BP, and office BP. Sedentary African American adults (53.4±6.2 years; 21 women and 5 men) showed improved vascular health but no change in BP. Carotid artery IMT decreased 6.4%, plasma nitric oxide levels increased 76.6%, plasma EMP levels decreased, percentage of FMD increased 59.6%, and FMD/NMD ratio increased 36.2% (P<.05 for all). Six months of aerobic exercise training is sufficient to elicit improvements in vascular structure and function in African Americans, even without improvements in BP measures or NMD (ie, smooth muscle function). To our knowledge, this is the first study to report such findings in African Americans.

A standardized exercise intervention differentially affects premenopausal and postmenopausal African-American women

ObjectiveAfrican-American women represent an understudied population in menopause research yet face greater postmenopausal challenges associated with mortality than their white peers. We investigated the effects of a mild-intensity aerobic exercise training program on markers of mortality risk in both premenopausal and postmenopausal African-American women. MethodsSixteen premenopausal women and 19 postmenopausal women underwent 6 months of mild-intensity aerobic exercise training. Measurements included markers of blood lipid and glucose profile, inflammation, kidney function, vascular health, and aerobic fitness before and after the exercise intervention. ResultsBefore the exercise intervention, the premenopausal and postmenopausal groups only differed in age, low-density lipoprotein, and total cholesterol levels, with the latter two being higher in the postmenopausal group. Both triglycerides and markers of early-stage endothelial dysfunction (CD62E+ endothelial microparticles) improved in both groups with aerobic exercise training. Aerobic fitness, glomerular filtration rate, body mass index, plasma glucose levels, and markers of late-stage endothelial dysfunction (CD31+/CD42b− endothelial microparticles) only improved in the premenopausal group. ConclusionsMild-intensity aerobic exercise training succeeds in improving some markers of cardiovascular disease and mortality in postmenopausal women. Higher levels of exercise intensity or perhaps additional interventions may need to be considered to further decrease mortality risk in this population.

Chronic aerobic exercise improves blood pressure dipping status in African American nondippers.

ObjectiveThe effects of exercise training on nocturnal blood pressure (BP) dipping status remain unclear. African Americans have the highest prevalence of nondippers compared with other racial/ethnic populations. In this 6-month study we tested the hypothesis that long-term aerobic exercise training would increase the levels of nocturnal BP dipping in African American nondippers. Methods and resultsWe recruited African Americans who were nondiabetic, nonsmoking, and free from cardiovascular and renal disease. For this analysis, only African Americans with a nondipping profile, defined as those with the absence of a nocturnal decline in systolic or diastolic BP (<10% of daytime values), which was determined by ambulatory BP monitoring, were chosen. A pre–post design was used, with baseline and final evaluation including office blood pressure measurement, 24-h ambulatory blood pressure monitoring, fasted blood sampling, and graded exercise testing. Participants engaged in 6 months of supervised aerobic exercise training (AEXT). Following the AEXT intervention, there were significant increases in systolic BP dipping (baseline: 5.8±3.9% vs. final: 9.4±6.1%, P=0.0055) and pulse pressure dipping (baseline: −3.1±6.6% vs. final: 5.0±12.8%, P=0.0109). Of the 18 participants with a nondipping profile at baseline, eight were nonclassified as nondippers after the AEXT intervention. There were no significant changes in office systolic BP/diastolic BP values following the AEXT intervention. ConclusionThis study suggests that the nondipping pattern of ambulatory BP can be improved by chronic AEXT in African American nondippers, regardless of a change in the 24-h average BP. This finding may be clinically important because of the target organ implication of nondipping nocturnal BP.

Adherence to Exercise Prescription and Improvements in the Clinical and Vascular Health of African Americans

Improvements in indices of vascular health and endothelial function have been inversely associated with hypertension, a risk factor for cardiovascular disease (e.g., myocardial infarction, stroke, and heart failure), renal failure, and mortality. Aerobic exercise training (AEXT) has been positively associated with improvements in clinical health values, as well as vascular health biomarkers, and endothelial function. The purpose of this study was to evaluate whether measures of exercise adherence were related to clinical outcome measures and indices of vascular health subsequent to a 6-month AEXT intervention in a middle-to-older aged African American cohort. Following dietary stabilization, sedentary, apparently healthy, African American adults (40 - 71 y/o) underwent baseline testing including blood pressure, flow-mediated dilation (FMD) studies, fasting blood sampling, and graded exercise testing. Upon completion of a supervised 6-month AEXT intervention, participants repeated all baseline tests. Exercise adherence was measured three ways: exercise percentage, exercise volume, and exercise score. There were no significant correlations between the changes in the vascular health biomarkers of the participants and any of the adherence measures. In addition, there were no significant correlations between any of the adherence measures and the clinical values of the participants that had been significantly changed pre-post-AEXT. Participants improved their clinical and vascular health and decreased risk factors for hypertension and cardiovascular disease regardless of their level of adherence to AEXT. Future studies should continue to accurately quantify adherence in order to assess the exercise dose for improvements in vascular and clinical health.

Differential response to exercise in African Americans with high levels of inflammation

PURPOSE Systemic inflammation, measured by C-reactive protein (CRP), is an important risk factor for cardiovascular disease (CVD) and mortality. We investigated whether aerobic exercise training (AEXT) affects African Americans with high inflammation (HI) the same way it does African Americans with low inflammation (LI) in terms of CVD risk factors. METHODS 23 African Americans with CRP levels <3 mg/L (LI) and 14 African Americans with CRP ≥3 mg/L (HI) underwent six months of AEXT. Participants were sedentary, non-diabetic, non-smoking, with clinical blood pressure <160/100 mm Hg, were non-hyperlipidemic, had no signs of cardiovascular, renal, or pulmonary disease, and were not on medication. Measures included CD62E+ endothelial microparticles (EMPs), a measure of early stage endothelial dysfunction, as well as lipid and glucose profile, aerobic fitness, body composition, and blood pressure. RESULTS The LI group improved aerobic fitness by 10%, body mass index by 3%, and plasma triglycerides by 20%, with no change being observed in HI group for these variables. The HI group improved fasting plasma glucose levels by 10%, with no change occurring in the LI group. Both groups improved CD62E+ EMPs by 38% and 59% for the LI and HI group, respectively. CONCLUSIONS A standard AEXT intervention differentially affected CVD risk factors among African Americans with high and low inflammation. This may indicate that, in African Americans with high inflammation, AEXT alone may not be enough to reap the same benefits as their low-inflammation peers in terms of CVD risk modification.

191 SIX-MONTHS OF LIFESTYLE INTERVENTION IMPROVES FLOW MEDIATED DILATION IN SEDENTARY AFRICAN AMERICAN SUBJECTS

Background: African-Americans have increased morbidity and mortality rates from cardiovascular disease (CVD). Diminished flow mediated dilation (FMD) is associated with CVD. Our study aimed to assess the efficacy of 6-months of diet and exercise intervention on FMD in African-American subjects. Methods: African-American subjects (N = 20, 17F/3 M, 53 ± 6yrs) who were sedentary, non-diabetic, non-smoking, free of CVD and not on medication completed 6-months of supervised aerobic exercise training (3 days/week, 65% of VO2max, 40 min/session). 6-weeks prior to initiation of exercise training, subjects underwent dietary stabilization under the supervision of a registered dietician and were required to strictly follow an AHA low-fat, low-salt diet for the duration of the study which was regularly monitored through a 3 days/week diet log. %FMD was defined as percentage change in brachial artery diameter at 1 min after reactive hyperemia, and was evaluated by a 7.5 MHz transducer of HP SONOS 5500. Results: FMD data were checked for normality of distribution with the Wilks’ Shapiro test. On repeated measures ANCOVA, the mean %FMD were statistically significantly different (F (1, 16) = 5.582, P = 0.031) between before vs. after training (Mean ± SEM; 6.4 ± 2.6% vs. 9.4 ± 2.1%), after adjusting for changed variables (BMI, total-cholesterol and C-reactive protein) as covariates. Conclusion: Our study showed that 6-months of diet and exercise intervention enhanced FMD by ∼32% in sedentary African-Americans. Improvement in endothelial-dependent FMD may contribute to the cardiovascular health benefits of lifestyle modification strategies in preventing CVD.