The impact of a plant-based diet on indices of cardiovascular health in African Americans: a cross-sectional study.

African-American (AA) individuals are disproportionately affected by cardiovascular diseases. Plant-based diets (PBD) may be cardioprotective in part through their high antioxidant capacity and low inflammatory load. We tested the hypothesis that AA individuals adhering to a 100% PBD would have better vascular health than AA individuals following a typical American diet (TAD). Eighteen AA individuals participated; 9 (24 ± 4 years; 6 females) were following a PBD for 2.4 ± 0.8 years and 9 (21 ± 2 years; 5 females) were following a TAD. Blood lipids and C-reactive protein (CRP) were assessed. Peripheral and central blood pressure (BP) were measured, and vascular function tests included cerebrovascular reactivity to hypercapnia, brachial artery flow-mediated dilation and reactive hyperemia, and local heating-induced cutaneous hyperemia. Total (TC) and low-density lipoprotein (LDL-C) serum cholesterol was lower (TC: 142 ± 30 vs. 174 ± 36 mg/dL; LDL-C: 76 ± 17 vs. 106 ± 33 mg/dL; p < 0.05 and d > 0.80 for both) and serum CRP tended to be lower (0.38 ± 0.18 mg/L vs. 0.96 ± 0.89 mg/L; p = 0.05, d = 0.91) in the PBD cohort. Brachial (b) and central (c) mean arterial BP (MAP) were lower in the PBD cohort (bMAP: 86 ± 5 vs. 91 ± 7 mm Hg; cMAP: 81 ± 5 vs. 87 ± 7 mm Hg; p < 0.05 and d > 0.80 for both). All indices of vascular function were similar between groups (p > 0.05 for all). A PBD was associated with more optimal blood lipid concentrations and decreased peripheral and central BP in AA individuals, but this association was not present in the various indices of vascular function. Registered at ClinicalTrials.gov: NCT05344287.

Young, non-Hispanic Black men and women exhibit divergent peripheral and cerebral vascular reactivity.

NEW FINDINGS: What is the central question of the study? Do peripheral and cerebral vascular function differ between 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 USA, 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 vasodilatation 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) years) participated in this study. Each participant underwent testing for brachial artery flow-mediated dilatation (FMD), post-occlusive reactive hyperaemia and cerebral vasomotor reactivity during rebreathing-induced hypercapnia. BW exhibited greater adjusted FMD than BM (P < 0.05 for all), but similar or lower reactive hyperaemia 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.

Contributions of endothelin-1 and l-arginine to blunted cutaneous microvascular function in young, black women.

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.

Blunted hyperemic response to mental stress in young, non-Hispanic black men is not impacted by acute dietary nitrate supplementation.

Non-Hispanic black individuals suffer from an elevated prevalence of hypertension and cardiovascular disease (CVD) relative to other populations. This elevated disease risk is, in large part, related to impaired vascular function, secondary to reduced nitric oxide (NO) bioavailability. Emerging evidence suggests that dietary nitrate supplementation improves several cardiovascular parameters, including vascular function, in part by increased NO bioavailability. However, whether these findings extend to a population of black individuals is unknown. This study tested the hypothesis that forearm blood flow responses in young, non-Hispanic, black (BL) men during a mental stress challenge would be blunted relative to young, non-Hispanic, white (WH) men. We further hypothesized that acute dietary nitrate supplementation would improve this response in BL men. This study comprised two parts (phase 1 and phase 2). Phase 1 investigated the difference in blood flow responses between young, BL, and WH men. In contrast, phase 2 investigated the effect of acute nitrate supplementation on the responses in a subset of the BL men from phase 1. Eleven (nine for phase 2) BL and eight WH men (23 ± 3 vs. 24 ± 4 yr, respectively) participated in this double-blind, placebo-controlled, randomized, crossover study. During each visit, hemodynamic responses during 3 min of mental stress were assessed in the brachial artery using duplex Doppler ultrasound. Phase 1 was completed in one visit, whereas phase 2 was completed over two visits separated by ∼1 wk. During phase 2, data were collected before and 2-h postconsumption of a beverage either high in nitrate content or nitrate depleted. In phase 1, peak forearm blood flow (FBF; P < 0.001), total FBF (P < 0.01), and forearm vascular conductance (FVC; P < 0.001) were blunted in the BL. During phase 2, prebeverage responses were similar to phase 1 and were unaffected following beverage consumption (P > 0.05 vs. prebeverage for all variables). These data indicate that young, BL men have blunted microvascular vasodilatory responses to acute mental stress, which may not be altered following acute nitrate supplementation.NEW & NOTEWORTHY This study tested the hypothesis that non-Hispanic black (BL) men have a blunted forearm hyperemic response to mental stress, which would be augmented following acute nitrate supplementation. The increase in forearm blood flow during mental stress was attenuated in BL men and was not impacted by nitrate supplementation. This supports findings of altered vascular function in this population. This is especially important as BL experience a higher prevalence of stress, which contributes to CVD risk.

Impact of daily strawberry consumption on blood pressure and arterial stiffness in pre- and stage 1-hypertensive postmenopausal women: a randomized controlled trial.

Growing evidence indicates that strawberries are cardioprotective. We conducted an eight-week randomized, double-blind, placebo-controlled, parallel arm clinical trial to investigate the effects of daily consumption of freeze-dried strawberry powder (FDSP) on blood pressure (BP) and arterial stiffness in pre- and stage 1-hypertensive postmenopausal women. Sixty postmenopausal women were randomly assigned to one of three groups: (1) control, (2) 25 g FDSP and (3) 50 g FDSP (n = 20 per group). Assessments of body weight, BP, arterial stiffness as measured by pulse wave velocity (PWV), and collection of blood samples for analyses of vasoactive and antioxidant molecules were performed at baseline, four and eight weeks. After eight weeks, systolic BP, as well as brachial- and femoral-ankle PWV were lower than baseline in the 25 g FDSP group (141 ± 3 to 135 ± 3 mmHg, P = 0.02; 15.5 ± 0.5 to 14.8 ± 0.4 m s-1, P = 0.03, and 11.0 ± 0.2 to 10.4 ± 0.2 m s-1, P = 0.02, respectively), whereas no statistically significant changes were observed in the control or 50 g FDSP groups. Plasma nitric oxide metabolite levels increased at four and eight weeks in the 50 g FDSP group compared to baseline (8.5 ± 1.2 to 13.6 ± 1.3 and 13.3 ± 1.5, respectively, P = 0.01), whereas no significant changes were observed in the control or 25 g FDSP groups. Serum levels of superoxide dismutase increased at four weeks returning to baseline levels at eight weeks in all three groups. Significant differences among groups were not detected for any of the parameters. Although BP and arterial stiffness improved in the 25 g FDSP group over time, a treatment effect was not observed. Thus, it would be premature to affirm that daily consumption of FDSP improves BP or vascular function in pre- and stage 1-hypertensive postmenopausal women. This trial was registered at as NCT02099578.

Benefits of whole-body vibration training on arterial function and muscle strength in young overweight/obese women.

The early arterial dysfunction linked with obesity and a sedentary lifestyle heightens the likelihood of suffering from future cardiovascular events. Whole-body vibration training (WBVT) may improve systemic arterial stiffness (brachial-ankle pulse wave velocity (baPWV)) and muscle strength in pre- and post-menopausal women. However, the effectiveness of WBVT to impact the arterial segments included in baPWV is unknown. The aim of this study was to investigate the effects of WBVT on aortic and leg arterial stiffness in young sedentary overweight/obese women. Thirty-eight young (21 years) overweight/obese women were randomized to WBVT (n=25) or a nonexercising control (CON, n=13) groups for 6 weeks. PWV, brachial and aortic blood pressures (BP), wave reflection (augmentation index (AIx)) and leg muscle strength measurements were acquired before and after 6 weeks. WBVT significantly reduced carotid-femoral PWV (aortic stiffness, P<0.05), femoral-ankle (leg arterial stiffness, P<0.01) and baPWV (systemic arterial stiffness, P<0.01) compared with CON. The reduction in brachial systolic BP (SBP), heart rate, aortic SBP, aortic diastolic BP, AIx normalized to a heart rate of 75 beats per min (AIx@75; P<0.01) and AIx (P<0.05) following WBVT was significant compared with CON (P<0.05). WBVT increased leg muscle strength compared with CON (P<0.001). There was a significant negative correlation between changes in relative muscle strength and aortic stiffness (r=-0.41, P<0.05). WBVT led to reductions in arterial stiffness, central BP and wave reflection in young obese women. WBVT may be an effective intervention toward vascular health promotion and prevention in young overweight/obese women (ClinicalTrials.gov identifier: NCT02679898).

Influence of low and normal appendicular lean mass on central blood pressure and wave reflection responses to muscle metaboreflex activation in postmenopausal women.

Sarcopenia, defined by reduced appendicular skeletal muscle mass (ASM)/height2 (ASMI), is associated with increased arterial stiffness (brachial-ankle pulse wave velocity, baPWV) and wave reflection (augmentation index, AIx). Blood pressure (BP) responses to metaboreflex activation (post-exercise muscle ischemia, PEMI) are exaggerated in older prehypertensives and hypertensives. We examined peripheral and aortic haemodynamics at rest and during PEMI in postmenopausal women with low-ASMI and normal-ASMI. Resting radial AIx and baPWV as well as brachial and aortic systolic BP, pulse pressure, systolic time index, and subendocardial viability ratio (SEVR) responses to PEMI were greater in women with low-ASMI than normal-ASMI. Increased baPWV associated with low-ASMI may play a major role in the exaggerated pulse pressure and SEVR responses to PEMI in postmenopausal women.

Impact of age on aortic wave reflection responses to metaboreflex activation and its relationship with leg lean mass in post-menopausal women.

Wave reflection (augmentation pressure [AP] and index [AIx]) is greater in older women than men. Resting AP is a better wave reflection index than AIx in older adults. The negative relationship between wave reflection and lean mass (LM) has been inconsistent. We investigated the impact of age and LM on aortic hemodynamic responses to metaboreflex activation in post-menopausal women. Post-menopausal women, younger and older (n=20 per group) than 60 years, performed 2-min isometric handgrip at 30% of maximal force followed by 3-min post-exercise muscle ischemia (PEMI). We measured carotid-femoral pulse wave velocity (cfPWV) and femoral-ankle PWV (faPWV) at rest, and aortic systolic blood pressure (aSBP), pulse pressure (aPP), AP, AIx, and AIx-adjusted for heart rate (AIx@75) at rest and during PEMI using tonometry. Arm and leg LM were measured by DEXA. Resting cfPWV, aSBP, and aPP were higher, while AIx@75 and leg LM were lower in older than younger women. aSBP and aPP increased similarly during PEMI in both groups. Increases in AP (P<0.05), AIx (P<0.05), and AIx@75 (P<0.01) during PEMI were greater in older than younger women. From these responses, only AP during PEMI was correlated (P<0.05) positively with aSBP and aPP responses, and negatively with leg LM. Resting faPWV, but not cfPWV, was correlated (P<0.01) with AP, aSBP, and aPP during PEMI. Therefore, PEMI induces greater wave reflection responses in older than younger post-menopausal women. Our findings suggest that the increased AP response to PEMI is related to leg arterial stiffness and muscle loss in older women.

Aortic Hemodynamics and Arterial Stiffness Responses to Muscle Metaboreflex Activation With Concurrent Cold Pressor Test.

BACKGROUND: Overweight/obese young men have increased sympatho-excitation to cold and pain stress-induced by the cold pressor test (CPT) that may lead to abnormal hemodynamic responses. Concurrent CPT and exercise may augment the sympathetic-induced increases in aortic blood pressure (BP), pressure wave reflection (augmentation index, AIx), and arterial stiffness (pulse wave velocity, PWV). Since obesity is related with hypertension and sympathetic activity, we evaluated the aortic hemodynamic and PWV responses to muscle metaboreflex activation imposed by postexercise muscle ischemia (PEMI) concurrent with CPT in overweight/obese men. METHODS: In 16 healthy (body mass index >25 and <40kg/m(2)) men (24±2 years), heart rate (HR), brachial BP, aortic BP, augmented pressure (AP), AIx, AIx adjusted to 75 beats/min (AIx@75), reflection time (Tr), first (P1) and second systolic peak (P2, wave reflection magnitude), and PWV (brachial-ankle PWV, baPWV) were evaluated at baseline, during isometric-handgrip exercise (IHG), and PEMI with (PEMI + CPT) and without CPT. RESULTS: During IHG, brachial BP, aortic BP, AP, AIx, AIx@75, P1, and P2 increased ( P < 0.01) while Tr decreased ( P < 0.05) compared with baseline. During PEMI, all hemodynamic parameters remained elevated ( P < 0.05) and baPWV increased (P < 0.05) while Tr and HR returned to baseline. Compared with PEMI, the increases in HR, brachial BP, aortic BP, AIx@75, P1, P2, and baPWV were greater ( P < 0.05) during PEMI + CPT. During PEMI + CPT, Tr remained lower ( P < 0.05) than baseline. CONCLUSIONS: Cold exposure with concurrent metaboreflex activation induces a significant increase in aortic hemodynamics and arterial stiffness, which may explain the high risk of adverse cardiovascular events during physiological stress. CLINICAL TRIALS REGISTRATION: Trial Number NCT02104375.

Impact of L-citrulline supplementation and whole-body vibration training on arterial stiffness and leg muscle function in obese postmenopausal women with high blood pressure.

Aging is associated with increased arterial stiffness (pulse wave velocity, PWV) and muscle strength/mass loss. Exercise training alone is not always effective to improve PWV and lean mass (LM) in older women. To investigate the independent and combined effects of whole-body vibration training (WBVT) and L-citrulline supplementation on PWV and muscle function in women, forty-one postmenopausal women aged 58 ± 3 years and body mass index (34 ± 2 kg/m(2)) were randomly assigned to the following groups: WBVT, L-citrulline, and WBVT + L-citrulline for 8 weeks. WBVT consisted of four leg exercises three times weekly. Aortic (cfPWV) and leg (faPWV) PWV, leg LM index, leg strength, and body fat percentage (BF%) were measured before and after the interventions. WBVT + L-citrulline decreased cfPWV (-0.91 ± 0.21 m/s, P < 0.01) compared to both groups. All interventions decreased faPWV (P < 0.05) similarly. Leg LM index increased (2.7 ± 0.5%, P < 0.001) after WBVT + L-citrulline compared with L-citrulline. Both WBVT interventions increased leg strength (~37%, P < 0.001) compared to L-citrulline while decreased BF% (~2.0%, P < 0.01). Reductions in cfPWV were correlated with increases in leg LM index (r = -0.63, P < 0.05). Our findings suggest that leg muscle strength and arterial stiffness can be improved after WBVT, but its combination with L-citrulline supplementation enhanced benefits on aortic stiffness and leg LM. Therefore, WBVT + L-citrulline could be an intervention for improving arterial stiffness and leg muscle function in obese postmenopausal women with prehypertension or hypertension, thereby reducing their cardiovascular and disability risk.

Vasodilation to PTH (1-84) in bone arteries is dependent upon the vascular endothelium and is mediated partially via VEGF signaling.

BACKGROUND: Intermittent PTH administration directly stimulates osteoblasts; however, mechanisms of bone accrual that are independent of the direct actions on osteoblasts may be under-appreciated. Our aims were to decipher (1) whether PTH 1-84 augments vasodilation of the femoral principal nutrient artery (PNA), (2) whether 15 days of intermittent PTH 1-84 augments endothelium-dependent and/or -independent vasodilation of the femoral PNA, and (3) the signaling mechanisms involved. METHODS: Experiment 1: Femoral PNAs from male Wistar rats were exposed to cumulative doses of PTH 1-84 with and without an anti-vascular endothelial growth factor antibody and/or the endothelial NO synthase inhibitor l-NAME. Experiment 2: Male Wistar rats were administered PTH and/or the anti-VEGF antibody for 2 weeks. Subsequently, endothelium-dependent vasodilation to acetylcholine and endothelium-independent vasodilation to sodium nitroprusside were assessed. In addition, endothelium-dependent signaling pathways were analyzed by use of l-NAME and/or and the cyclooxygenase inhibitor indomethacin. RESULTS: Cumulative doses of PTH 1-84 induced vasodilation of the femoral PNA, which was reduced by 38% and 87% with the anti-VEGF antibody and l-NAME, respectively. Secondly, 2 weeks of intermittent PTH 1-84 administration doubled trabecular bone volume, augmented bone formation parameters and reduced osteoclast activity. In addition, PTH enhanced endothelium-dependent vasodilation via up-regulation of NO. Co-administration of the anti-VEGF antibody (1) inhibited the PTH-induced increase in bone volume and remodeling parameters and (2) blunted the augmented vasodilator responsiveness of the PNA. Finally, endothelium-dependent vasodilation in PTH-treated rats was highly correlated with trabecular bone volume. CONCLUSION: As hypothesized, PTH enhanced endothelium-dependent vasodilation of the femoral PNA via augmented NO production and was mediated partially through VEGF signaling. Further, vasodilation to PTH appears independent of vascular smooth muscle cell participation. More importantly, the strong association between vasodilation and bone volume suggests that bone arteriolar function is critical for PTH-induced bone anabolism.