Effect of gender and adiposity on in vivo vascular function in young African Americans

Anthropometric measurements and their association with endothelial function and arterial stiffness of eutrophic individuals and with overweight

Objective

The objective of the study was to assess the association of anthropometric measurements with endothelial function and arterial stiffness of eutrophic individuals and with overweight.

Subjects and methods

A cross-sectional study was carried out with individuals with body mass index (BMI) between 18.5 kg/m2 and < 30 kg/m2, low to intermediate global cardiovascular risk scores, and aged ≥ 18 and < 60 years. We assessed the sociodemographic data, anthropometric variables (body weight, height, circumferences of the waist [WC], neck [NC], hip [HC], sagittal abdominal diameter [SAD], [BMI], waist-to-hip ratio [WHR], and waist-to-height ratio [WHtR]), biochemical parameters (lipid profile and nitric oxide), endothelial function (flow-mediated dilation [FMD], by ultrasound), and arterial stiffness (pulse wave velocity [PWV] and the amplification index [AIx@75] by oscillometry). Thirty-six individuals were included, 18 eutrophic and 18 with overweight, with a mean age of 37.5 ± 10.2 years, mostly at low cardiovascular risk (86.1%), female (80.6%), single (52.8%), employed with formal contracts (44.4%), and with over twelve years of education (88.9%).

Results

The PWV presented positive and moderate correlation with the WC (r = 0.584; P = 0.001), WHR (r = 0.513; P = 0.001), and WHtR (r = 0.590; P = 0.001), and positive and low correlation with the NC (r = 0.372; P = 0.013) and SAD (r = 0.356; P = 0.033). Moreover, no anthropometric parameter presented a correlation with the AIx@75 or the FMD percentage in the total sample.

Conclusion

Our findings show that in eutrophic individuals and with overweight the WC, WHR, WHtR, SAD, and NC were positively correlated with the PWV but not to the endothelial function in the overall sample. These are hypothesis-generating findings and they should be replicated in other studies.

Young, non-hispanic black men and women exhibit divergent peripheral and cerebral vascular reactivity

NEW FINDINGS

What is the central question of the study? Does peripheral and cerebral vascular function differ in young, non-Hispanic Black men and women? What is the main finding and its importance? The non-Hispanic, Black women in this study presented greater peripheral conduit artery and cerebrovascular reactivity, yet similar peripheral microvascular function relative to the non-Hispanic, Black men. These preliminary findings suggest that young, Black women and men possess divergent vascular function, possibly contributing to the unique non-Hispanic Black sex differences in cardiovascular and cerebrovascular diseases.

ABSTRACT

In the U.S., cardiovascular and cerebrovascular diseases remain more prominent in the non-Hispanic Black (BL) population relative to other racial/ethnic groups. Typically, sex differences emerge in the manifestation of these diseases, though these differences may not fully materialize in the BL population. While numerous mechanisms are implicated, differences in vascular function likely contribute. Research has demonstrated blunted vasodilation in several vascular regions in BL versus non-Hispanic White individuals, though much of this work did not assess sex differences. Therefore, this study aimed to ascertain if indices of vascular function are different between young, BL women (BW) and men (BM). Eleven BW and 15 BM (22 (4) vs. 23 (3) y) participated in this study. Each participant underwent testing for brachial artery flow-mediated dilation (FMD), post-occlusive reactive hyperemia (RH), and cerebral vasomotor reactivity during rebreathing-induced hypercapnia. BW exhibited greater adjusted FMD than BM (P < 0.05 for all), but similar or lower RH when assessed as blood velocity (P > 0.39 for all) or blood flow reactivity (P < 0.05 for all), respectively. Across a range of hypercapnia, BW had greater middle cerebral artery blood velocity and cerebrovascular conductance index than BM (P < 0.001 for both). These preliminary data suggest that young, BW have greater vascular function relative to young, BM, though this was inconsistent across different indices. These findings provide insight into the divergent epidemiological findings between BM and BW. Further research is needed to elucidate possible mechanisms and relate these physiological responses to epidemiological observations. This article is protected by copyright. All rights reserved.

Dietary Sodium Restriction Results in Tissue-Specific Changes in DNA Methylation in Humans

[Figure: see text].

Sex-related differences in forearm skin microvascular reactivity of young healthy subjects

OBJECTIVE

To assess sex-related differences in forearm skin microvascular reactivity to vascular occlusion and cardiovascular health in young healthy women and men.

METHODS

203 young healthy individuals (67 men/136 women) participated in this study. Post-occlusive reactive hyperemia (PORH) in skin microcirculation following 1', 2' and 3' vascular occlusion period was assessed using laser Doppler flowmetry. Anthropometric parameters, body composition, blood pressure, heart rate and biochemical parameters were measured in all participants. Correlations between PORH and measured parameters were determined by using corresponding tests.

RESULTS

Women had significantly higher forearm PORH following 1', 2' and 3' vascular occlusion than men. Women had lower body mass index and waist-to-hip ratio, but higher fat mass than men. Men had significantly higher blood pressure and lower heart rate than women. Also, women had lower hemoglobin, urea, creatinine and serum uric acid, but higher HDL cholesterol level than men. PORH was negatively associated with waist-to-hip ratio and systolic blood pressure only in women.

CONCLUSIONS

Young healthy women exhibit higher skin microvascular reactivity to vascular occlusion compared to age-matched men. Increased systolic blood pressure or central obesity (waist-to-hip ratio) may pose greater risk to young healthy women than men by adversely affecting peripheral microvascular function.

Tipping the scales: Are females more at risk for obesity- and high-fat diet-induced hypertension and vascular dysfunction?

Obesity is a common metabolic disorder that has become a widespread epidemic in several countries. Sex and gender disparities in the prevalence of cardiovascular disease (CVD) have been well documented with premenopausal women having a lower incidence of CVD than age-matched men. However, women are more likely than men to suffer from obesity, which can predispose them to a greater risk of CVD. The mechanisms underlying high-fat diet (HFD)- or obesity-induced hypertension are not well defined, although immune system activation and inflammation have been implicated in several studies. Further, the sex of the subject can have a profound influence on the immune response to hypertensive stimuli. Therefore, the purpose of this review is to examine the effects of sex and gender on the role of the immune system in HFD-induced hypertension and vascular dysfunction. LINKED ARTICLES: This article is part of a themed section on The Importance of Sex Differences in Pharmacology Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.21/issuetoc.

Assessment of dapagliflozin effect on diabetic endothelial dysfunction of brachial artery (ADDENDA-BHS2 trial): rationale, design, and baseline characteristics of a randomized controlled trial

BACKGROUND

Endothelial dysfunction (ED) is a hallmark in type 2 diabetes mellitus (T2DM) that favor both atherogenesis and ischemia and reperfusion injury (IRI). Sodium-glucose-2 co-transporter inhibitors (SGLT2i) may hypothetically improve microvascular and macrovascular functions via a broad spectrum of mechanisms, being superior to traditional antidiabetic therapy such as sulfonylurea, even in subjects under equivalent glycemic control. Hence, the present clinical trial was designed to compare the effect of these two treatments on markers of arterial wall function and inflammation in T2DM patients as well as on the potential mediating parameters.

METHOD AND RESULTS

ADDENDA-BHS2 is a prospective, single-center, active-controlled, open, randomized trial. Ninety-eight participants (40-70 years old) with HbA1c 7-9% were randomized (1:1, stratified by gender, BMI and HbA1c levels) to either dapagliflozin 10 mg/day or glibenclamide 5 mg/day on top of metformin. The primary endpoint was the change of flow-mediated dilation (FMD) after a 12-week period of treatment evaluated at rest and after IRI between dapagliflozin and glibenclamide arms. Secondary outcomes were defined as the difference between treatments regarding: plasma nitric oxide (NO) change after FMD, plasma isoprostane, plasma levels of vascular inflammatory markers and systemic inflammatory markers, plasma levels of adipokines, anthropometric measures, glucose control parameters, office and ambulatory BP control. Safety endpoints were defined as systolic and diastolic function assessed by echocardiography and retinopathy change. Serious adverse events were recorded. The study protocol was approved by the Independent Scientific Advisory Committee.

CONCLUSION

The ADDENDA-BHS2 trial is an investigator-initiated clinical trial comparing the effect of dapagliflozin versus glibenclamide on several aspects of vascular function in high cardiovascular risk T2DM patients. Besides, a large clinical and biochemical phenotype assessment will be obtained for exploring potential mediations and associations.Trial registration Clinical trial registration: NCT02919345 (September, 2016).

Ethnic Disparities in Endothelial Function and Its Cardiometabolic Correlates: The Pathobiology of Prediabetes in A Biracial Cohort Study

BACKGROUND

Endothelial function (EF) reflects the balance between vasodilatory and vasoconstrictive factors produced by (or acting on) the innermost lining of blood vessels. Endothelial dysfunction, an imbalance between these factors that favors vasoconstriction, has been associated with increased risk for cardiovascular disease. However, the influence of race/ethnicity and glycemic status on association between EF and cardiovascular risk factors remain to be clarified.

SUBJECTS AND METHODS

We assessed EF in relation to glycemia and cardiometabolic profile in African-American (AA) and European-American (EA) offspring of parents with type 2 diabetes (T2D), who are participants in the prospective pathobiology and reversibility of prediabetes in a biracial cohort (PROP-ABC) study. Assessments at enrollment included a 75 g oral glucose tolerance test (OGTT), blood pressure, anthropometry, body composition (DEXA), and lipid profile. Other assessments were insulin sensitivity and resting energy expenditure. EF was measured using flow-mediated vasodilation (EndoPAT 2000) and expressed as reactive hyperemia index (RHI).

RESULTS

We studied 190 subjects (100 AA, 90 C), mean age (±SD) 53.1 ± 9.1 years, and body mass index 30.6 ± 6.8 kg/m2. Based on OGTT data, 96 subjects (52 AA, 44 EA) had prediabetes and 94 subjects were normoglycemic (48 AA and 46 EA). The RHI was lower in AA than EA (2.17 ± 0.55 vs. 2.36 ± 0.72, P = 0.05) and in prediabetic than normoglycemic subjects (2.14 ± 0.62 vs. 2.38 ± 0.65, P = 0.013). Using RHI ≤ 1.68 as diagnostic cut-off, 19% of participants with prediabetes and 10% of normoglycemic participants had endothelial dysfunction (P = 0.04). In univariate models, RHI was positively associated with age and HDL cholesterol levels, and inversely associated with adiposity, diastolic blood pressure, and 2hr plasma glucose. The association between RHI and adiposity was stronger in men than women. The association between RHI and age, glucose and HDL cholesterol displayed marked ethnic disparities.

CONCLUSION

In our biracial cohort comprising offspring of parents with T2D, prediabetes increased the risk of endothelial dysfunction. However, the association between EF and cardiometabolic risk factors was significantly modified by ethnicity and gender. Our findings support current understanding of endothelial dysfunction as an early sensitive indicator of cardiometabolic risk.