Variations in endothelial function and arterial compliance during the menstrual cycle

Menstrual cycle and the protective effects of remote ischemic preconditioning against endothelial ischemia/reperfusion injury: comparison with postmenopausal women

The aim of this study was to determine whether the capacity of remote ischemic preconditioning (IPC) against endothelial ischemia/reperfusion (I/R) injury changes across the menstrual cycle in premenopausal women and to compare IPC responses to postmenopausal women. Thirty-five women were studied (22 premenopausal/13 postmenopausal). Changes in endothelial function were determined during the early follicular vs. the late follicular phase (after positive urine ovulation test; Study 1), vs. the mid-luteal phase (after positive urine progesterone test; Study 2), and vs. estrogen-deficient postmenopausal women; Study 3). Endothelium-dependent vasodilation was assessed by the forearm blood flow (FBF) to reactive hyperemia with/without I/R injury with remote IPC (3 × 5 min cycles of upper arm ischemia). In the premenopausal women, peak FBF responses during the early follicular phase were blunted 20% (P < 0.0001) with I/R injury (from baseline: 23.4 ± 6.2 to 19.5 ± 4.9 mL/100 mL tissue/min) compared with the late follicular/mid-luteal phases despite IPC. In postmenopausal women, peak FBF was diminished (from: 21.1 ± 5.1 to 17.2 ± 4.4 mL/100 mL tissue/min), and total FBF (area under the curve) was decreased a third (-32%; P < 0.001) with I/R injury. Protection from I/R injury was preserved during the late follicular (from baseline: 21.7 ± 5.3 to 24.8 ± 5.9 mL/100 mL tissue/min; P = 0.109) and mid-luteal phases (from: 25.1 ± 3.9 to 27.2 ± 5.7 mL/100 mL tissue/min; P = 0.267). Reduced estrogen during the early follicular phase and the rise in estrogen associated with ovulation and the mid-luteal phase may contribute to changes in IPC-mediated protection in premenopausal women and shed light on how cardioprotection may change with ovarian hormone deficiency with the menopause transition.NEW & NOTEWORTHY The capacity of remote ischemic preconditioning to protect against vascular endothelial ischemia/reperfusion injury varies widely across the phases of the menstrual cycle in healthy premenopausal women. Robust protection was afforded during the late follicular and mid-luteal phases. In contrast, weakened protection was demonstrated during the early follicular phase, with a level of impairment similar to estrogen-deficient postmenopausal women.

Breakfast skipping suppresses the vascular endothelial function of the brachial artery after lunch

Breakfast skipping has been suggested to be associated with cardiovascular diseases. However, whether breakfast skipping affects vascular endothelial function (VEF), a marker of cardiovascular diseases, remains unclear. This study aimed to investigate the impact of breakfast consumption (Eating trial) and skipping (Skipping trial) on brachial artery (BA) VEF in healthy breakfast eaters. A total of nine healthy individuals (4 females and 5 males) either had breakfast between 830 and 900 or skipped it and had lunch between 1200 and 1230, followed by a 3-h rest period until 1530. For BA VEF evaluation, flow-mediated dilation (FMD) was measured by ultrasound before and after breakfast and lunch. FMD was calculated as the percent change in BA diameter normalized to the shear rate area under the curve (FMD/SRAUC). Blood glucose, plasma insulin, and plasma free fatty acid levels in capillaries were measured before and after breakfast and lunch. At 1530, the Eating trial, but not the Skipping trial, significantly increased FMD/SRAUC from baseline (P = 0.006). The Skipping trial showed significantly lower changes in FMD/SRAUC from 830 than the Eating trial at 1530 (P < 0.001). We found a significant inverse correlation between changes in FMD/SRAUC between 830 and 1530 and peak glucose levels after lunch (r = -0.882, P < 0.001) and with an incremental area under the curve for glucose between 830 and 1530 (r = -0.668, P < 0.001). These results suggest that a single bout of breakfast skipping can suppress BA VEF in the afternoon because of postlunch hyperglycemia.NEW & NOTEWORTHY Skipping breakfast does not affect vascular endothelial function (VEF) before lunch. However, after lunch on normal meals (i.e., not oral glucose tolerance test), VEF was found to be lower in those who skipped breakfast than those who ate breakfast. Such reduced postlunch VEF after skipping breakfast was associated with postprandial hyperglycemia. These results provide important insight into the impact of eating breakfast on VEF and glycemic control in healthy adults.

Menstrual cycle does not impact the hypoxic ventilatory response and acute mountain sickness prediction

The relationship between the variations in ovarian hormones (i.e., estrogens and progesterone) and the hypoxic ventilatory response (HVR) remains unclear. HVR is a key adaptive mechanism to high altitude and has been proposed as a predictor for acute mountain sickness (AMS). This study aimed to explore the effects of hormonal changes across the menstrual cycle on HVR. Additionally, it assessed the predictive capacity of HVR for AMS and examined whether a particular menstrual phase could enhance its predictive accuracy. Thirteen eumenorrheic women performed a pure nitrogen breathing test near sea level, measuring HVR and cerebral oxygenation in early follicular, late follicular, and mid-luteal phases. Oxidative stress and ovarian hormone levels were also measured. AMS symptoms were evaluated after spending 14 h, including one overnight, at an altitude of 3,375 m. No differences in HVR, ventilation, peripheral oxygen saturation, or cerebral oxygenation were observed between the three menstrual cycle phases. Moreover, these parameters and the oxidative stress markers did not differ between the women with or without AMS (31% vs 69%), regardless of the menstrual cycle phase. In conclusion, ventilatory responses and cerebral oxygenation in normobaric hypoxia were consistent across the menstrual cycle. Furthermore, these parameters did not differentiate women with or without AMS.

Differences in cardiovascular risk factors associated with sex and gender identity, but not gender expression, in young, healthy cisgender adults

Background

Sex differences exist in cardiovascular disease risk factors including elevated blood pressure and arterial stiffness, and decreased endothelial function in males compared to females. Feminine gender expression may be associated with elevated risk of acute coronary syndrome. However, no study has investigated the associations between sex, gender identity, and gender expression and cardiovascular disease risk factors in young adults.

Methods

One hundred and thirty participants (22 ± 3 years) underwent assessments of hemodynamics, arterial stiffness [pulse wave velocity (PWV)], and brachial artery endothelial function (flow-mediated dilation; %FMD). Participants completed a questionnaire capturing sex category (50 male/80 female), gender identity category (49 men/79 women/2 non-binary), and aspects of gender expression assessed by the Bem Sex Role Inventory-30 (39 androgynous/33 feminine/29 masculine/29 undifferentiated). Sex/gender identity category groups were compared using unpaired t-tests and gender expression groups compared using one-way ANOVAs.

Results

Resting systolic and mean arterial pressure (p < 0.01) were elevated in males vs. females. Central PWV was elevated in males [median (interquartile range): 6.4 (1.8) vs. 5.8 (2.2) m/s, p = 0.02]; however, leg and arm PWV were not different between sexes. %FMD was elevated in males vs. females, after accounting for a larger baseline artery diameter in males (8.8 ± 3.3% vs. 7.2 ± 3.1%, p = 0.02); since the majority of participants were cisgender, the same results were found examining gender identity (men vs. women). There were no differences across gender expression groups (p > 0.05).

Conclusions

Sex/gender identity category, but not gender expression, influence cardiovascular risk factors (blood pressure, arterial stiffness, endothelial function) in cisgender adults; further research is needed in gender-diverse populations.

Uninterrupted prolonged sitting and arterial stiffness: moderating effect of prior aerobic exercise in physically active adults

PURPOSE

Prolonged sitting acutely increases arterial stiffness, with interruption strategies only providing limited success in offsetting these rises. Acute aerobic exercise is a potent stimulus to decrease arterial stiffness. However, limited information exists on the effectiveness of acute exercise to maintain arterial stiffness when performed prior to prolonged sitting, particularly within physically active individuals.

METHODS

Using a randomized crossover design, 22 young, active individuals (50% female) performed two conditions 30 min of walking at 55-65% of heart rate reserve (EX) and 30 min of standing (STAND) followed by 2.5-h of sitting. Brachial-femoral (bfPWV) and femoral-ankle pulse wave velocity (faPWV) were assessed at Baseline, post-exercise and pre-sitting (Pre), and post-sitting (Post) as estimates of central and peripheral arterial stiffness, respectively.

RESULTS

For bfPWV, no interaction, condition, or time effects were observed. For faPWV, an interaction was present (p < 0.001); compared to Baseline, there was a 6.1% decrease for EX (- 0.4 m/s, p < 0.001) and a 4.6% increase for STAND (0.3 m/s, p = 0.016) for STAND such that there was an 11.3% difference between conditions at Pre (0.7 m/s, p < 0.001). From Pre to Post, EX then increased by 11.7% (0.9 m/s p < 0.001) while STAND remained unchanged, resulting in no difference between conditions (0.1 m/s, p = 0.569).

CONCLUSIONS

While aerobic exercise resulted in a significant decrease in faPWV prior to sitting, the prior exercise bout did not confer a protective effect against the deleterious effects of uninterrupted sitting. Future work should investigate the combined effect of prior exercise and sitting interruption strategies on markers of arterial stiffness.

Jaboticaba berry (Myrciaria jaboticaba) supplementation protects against micro- and macrovascular dysfunction induced by eccentric exercise: a randomized clinical trial

Physical activities that are unaccustomed and involve eccentric muscle contractions have been demonstrated to temporarily impair macrovascular and microvascular functions, which may be caused by exercise-induced oxidative stress. Jaboticaba (Myrciaria jaboticaba) is a famous Brazilian berry that has been described to exhibit high antioxidant activity. However, no human study has investigated the protective effects of jaboticaba consumption against the vascular damage induced by eccentric exercise. Therefore, the present study aimed to assess whether supplementation with jaboticaba berry juice could positively affect macro- and microvascular functions within 48 hours after eccentric exercise. This randomized, double-blind, placebo-controlled, parallel trial enrolled 24 healthy participants consuming 250 mL per day of jaboticaba berry juice (containing ∼1,300 mg of total polyphenols) or placebo for 6 days. At the baseline, pre-exercise, and 24 h and 48 h postexercise stages, blood samples were taken for analysis of reduced glutathione (GSH) levels. Also, brachial artery flow-mediated dilation (FMD), blood flow, and tissue oxygen saturation (StO2) responses to 5-minute cuff occlusion were assessed using Doppler ultrasound and near-infrared spectroscopy, respectively. Our findings revealed significant decreases in blood GSH (P < 0.001, ES = 0.76), FMD (P = 0.005, ES = 0.48), reperfusion slope of StO2 (P = 0.018, ES = 0.42) at 24 h and blood flow (P = 0.012, ES = 0.42) at 48 h following eccentric exercise in the control group as compared to the jaboticaba berry juice group. Our results demonstrated that jaboticaba berry juice prevented the exercise-induced increase in reactive oxygen species production and protected macro- and microvascular functions against the damage caused by eccentric exercise, suggesting that jaboticaba berry consumption could protect the vascular function under conditions of imbalance in redox homeostasis.

Vascular adaptation to exercise: a systematic review and audit of female representation

Biological sex is a salient factor in exercise-induced vascular adaptation. Although a male bias is apparent in the literature, the methodological quality of available studies in females is not yet known. This systematic review with narrative synthesis aimed to assess available evidence of exercise interventions on endothelial function, measured using flow-mediated dilation, in otherwise healthy individuals and athletes. A standardized audit framework was applied to quantify the representation of female participants. Using a tiered grading system, studies that met best-practice recommendations for conducting physiological research in females were identified. A total of 210 studies in 5,997 participants were included, with 18% classified as athletes. The primary exercise mode and duration were aerobic (49%) and acute (61%), respectively. Despite 53% of studies (n = 111) including at least one female, female participants accounted for only 39% of the total study population but 49% of the athlete population. Majority (49%) of studies in females were conducted in premenopausal participants. No studies in naturally menstruating, hormonal contraceptive-users or in participants experiencing menstrual irregularities met all best-practice recommendations. Very few studies (∼5%) achieved best-practice methodological guidelines for studying females and those that did were limited to menopause and pregnant cohorts. In addition to the underrepresentation of female participants in exercise-induced vascular adaptation research, there remains insufficient high-quality evidence with acceptable methodological control of ovarian hormones. To improve the overall methodological quality of evidence, adequate detail regarding menstrual status should be prioritized when including females in vascular and exercise research contexts.

Mechanistic, participant, and movement-related factors that contribute to low-flow-mediated constriction

Endothelial function is commonly determined via the ultrasound-based flow-mediated dilation (FMD) technique which assesses arterial dilation in response to a hyperemia response following distal cuff occlusion. However, the low-flow-mediated constriction (L-FMC) response during cuff-induced ischemia is often overlooked. L-FMC provides unique information regarding endothelial function, but vascular researchers may be unclear on what this metric adds. Therefore, the objective of this review was to examine the mechanistic determinants and participant-level factors of L-FMC. Existing mechanistic studies have demonstrated that vasoreactivity to low flow may be mediated via non-nitric oxide vasodilators (i.e., endothelial hyperpolarizing factors and/or prostaglandins), inflammatory markers, and enhancement of vasoconstriction via endothelin-1. In general, participant-level factors such as aging and presence of cardiovascular conditions generally are associated with attenuated L-FMC responses. However, the influence of sex on L-FMC is unclear with divergent results between L-FMC in upper versus lower limb vessels. The ability of aerobic exercise to augment L-FMC (i.e., make more negative) is well supported, but there is a major gap in the literature concerning the mechanistic underpinnings of this observation. This review summarizes that while larger L-FMC responses are generally healthy, the impact of interventions to augment/attenuate L-FMC has not included mechanistic measures that would provide insight into non-nitric oxide-based endothelial function. Clarifications to terminology and areas of further inquiry as it relates to the specific pharmacological, individual-level factors, and lifestyle behaviors that impact L-FMC are highlighted. A greater integration of mechanistic work alongside applied lifestyle interventions is required to better understand endothelial cell function to reductions in local blood flow.

Repeated-Sprint Training at 5000-m Simulated Altitude in Preparation for the World Rugby Women's Sevens Series: Too High?

PURPOSE

The objective of this study is to investigate the effectiveness of novel repeated-sprint training in hypoxia (RSH) protocol, likely maximizing hypoxic stimulus (higher than commonly used) while preserving training quality (interset rest in normoxia).

METHODS

Twenty-three world-class female rugby sevens players performed four repeated-sprint training sessions (4 sets of 5 × 5-s cycle sprints-25-s intersprint recovery and 3-min interset rest) under normobaric hypoxia (RSH, exercise and interset rest at FiO 2 of 10.6% and 20.9%, respectively; n = 12) or normoxia (repeated-sprint training in normoxia; exercise and interset rest at FiO 2 of 20.9%; n = 11) during a 9-d training camp before international competition. Repeated-sprint ability (8 × 5-s treadmill sprints-25-s recovery), on-field aerobic capacity, and brachial endothelial function were assessed pre- and postintervention.

RESULTS

Arterial oxygen saturation (pooled data: 87.0% ± 3.1% vs 96.7% ± 2.9%, P < 0.001) and peak and mean power outputs (sets 1 to 4 average decrease: -21.7% ± 7.2% vs -12.0% ± 3.8% and -24.9% ± 8.1% vs -14.9% ± 3.5%; both P < 0.001) were lower in RSH versus repeated-sprint training in normoxia. The cumulated repeated-sprint distance covered significantly increased from pre- to postintervention (+1.9% ± 3.0%, P = 0.019), irrespective of the condition ( P = 0.149). On-field aerobic capacity did not change (all P > 0.45). There was no significant interaction (all P > 0.240) or condition main effect (all P > 0.074) for any brachial artery endothelial function variable. Only peak diameter increased ( P = 0.026), whereas baseline and peak shear stress decreased ( P = 0.014 and 0.019, respectively), from pre- to postintervention.

CONCLUSIONS

In world-class female rugby sevens players, only four additional repeated-sprint sessions before competition improve repeated-sprint ability and brachial endothelial function. However, adding severe hypoxic stress during sets of repeated sprints only did not provide supplementary benefits.

Sleep efficiency and PTSD symptom severity predict microvascular endothelial function and arterial stiffness in young, trauma-exposed women

Posttraumatic stress disorder (PTSD) is linked to sleep disturbances and significantly higher risk of developing cardiovascular disease (CVD). Furthermore, vascular dysfunction and sleep are independently associated with CVD. Uncovering the link between PTSD symptom severity, sleep disturbances, and vascular function could shine a light on mechanisms of CVD risk in trauma-exposed young women. The purpose of the present study was to investigate the individual and combined effects of sleep efficiency and PTSD symptom severity on vascular function. We recruited 60 otherwise healthy women [age, 26 ± 7 yr and body mass index (BMI), 27.7 ± 6.5 kg/m2] who had been exposed to trauma. We objectively quantified sleep efficiency (SE) using actigraphy, microvascular endothelial function via Framingham reactive hyperemia index (fRHI), and arterial stiffness via pulse-wave velocity (PWV). PTSD symptom severity was assessed using the PTSD checklist for fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) (PCL5). PWV was correlated with age (r = 0.490, P < 0.001) and BMI (r = 0.484, P < 0.001). In addition, fRHI was positively correlated with SE (r = 0.409, P = 0.001) and negatively correlated with PTSD symptoms (r = -0.382, P = 0.002). To explore the predictive value of SE and PTSD symptoms on PWV and fRHI, we conducted two multivariate linear regression models. The model predicting PWV was significant (R2 = 0.584, P < 0.001) with age, BMI, blood pressure, and SE emerging as predictors. Likewise, the model predicting fRHI was significant (R2 = 0.360, P < 0.001) with both PTSD symptoms and SE as significant predictors. Our results suggest that although PTSD symptoms mainly impact microvascular endothelial function, sleep efficiency is additionally associated with arterial stiffness in young trauma-exposed women, after controlling for age and BMI.NEW & NOTEWORTHY This is the first study to investigate the individual and combined impacts of objective sleep and PTSD symptoms severity on arterial stiffness and microvascular endothelial function in young premenopausal women. We report that in young trauma-exposed women, although low sleep efficiency is associated with overall vascular function (i.e., microvascular endothelial function and arterial stiffness), the severity of PTSD symptoms is specifically associated with microvascular endothelial function, after accounting for age and body mass index.

Endogenous estradiol contributes to vascular endothelial dysfunction in premenopausal women with type 1 diabetes

BACKGROUND

Endogenous estrogen is cardio-protective in healthy premenopausal women. Despite this favorable action of estrogen, animal models depict a detrimental effect of estradiol on vascular function in the presence of diabetes. The present study sought to determine the role of endogenous estradiol on endothelial function in women with type 1 diabetes.

METHOD

32 women with type 1 diabetes (HbA1c = 8.6 ± 1.7%) and 25 apparently healthy women (HbA1c = 5.2 ± 0.3%) participated. Flow-mediated dilation (FMD), a bioassay of nitric-oxide bioavailability and endothelial function was performed during menses (M) and the late follicular (LF) phase of the menstrual cycle to represent low and high concentrations of estrogen, respectively. In addition, a venous blood sample was collected at each visit to determine circulating concentrations of estradiol, thiobarbituric acid reactive substances (TBARS), and nitrate/nitrite (NOx), biomarkers of oxidative stress and nitric oxide, respectively. Data were collected in (1) 9 additional women with type 1 diabetes using oral hormonal birth control (HBC) (HbA1c = 8.3 ± 2.1%) during the placebo pill week and second active pill week, and (2) a subgroup of 9 demographically matched women with type 1 diabetes not using HBC (HbA1c = 8.9 ± 2.1%).

RESULTS

Overall, estradiol was significantly increased during the LF phase compared to M in both type 1 diabetes (Δestradiol = 75 ± 86 pg/mL) and controls (Δestradiol = 71 ± 76 pg/mL); however, an increase in TBARS was only observed in patients with type 1 diabetes (ΔTBARS = 3 ± 13 µM) compared to controls (ΔTBARS = 0 ± 4 µM). FMD was similar (p = 0.406) between groups at M. In addition, FMD increased significantly from M to the LF phase in controls (p = 0.024), whereas a decrease was observed in type 1 diabetes. FMD was greater (p = 0.015) in patients using HBC compared to those not on HBC, independent of menstrual cycle phase.

CONCLUSION

Endogenous estradiol increases oxidative stress and contributes to endothelial dysfunction in women with diabetes. Additionally, HBC use appears to be beneficial to endothelial function in type 1 diabetes.

Effect of aerobic and resistance exercise training on endothelial function in individuals with overweight and obesity: a systematic review with meta-analysis of randomized clinical trials

The objective of this systematic review was to examine the effects of exercise training on endothelial function in individuals with overweight and obesity. Our review study included only randomized controlled trials (RCTs) involving adults (≥ 18 years of age) with body mass index (BMI) ≥ 25.0 kg/m₂. Our search was conducted in the electronic bases MEDLINE (PubMed), Cochrane, LILACS and EMBASE and in the gray literature. We performed random-effects analyses for effect estimates and used 95% prediction intervals (95% PI) for estimating the uncertainty of the study results. There were selected 10 RCTs involving 14 groups (n = 400). The quality assessment of studies using Cochrane risk-of-bias 2 (RoB 2) tool identified some concerns. Exercise training resulted in improved flow-mediated dilation (FMD) in individuals with overweight and obesity (p < 0.001) compared to the no-exercise control group. This effect of training modalities on FMD was seen for aerobic training (p < 0.001) but not for resistance training (p = 0.051). There was no difference in FMD in response to exercise training by BMI classification (overweight, obesity, overweight + obesity), p = 0.793. The present results are consistent with the notion that aerobic exercise training elicits favorable adaptations in endothelial function in individuals with overweight and obesity. Our findings should be interpreted with caution because of the small number of studies included in this review.

Vascular Responses to Passive and Active Movement in Premenopausal Females: Comparisons across Sex and Menstrual Cycle Phase

PURPOSE

Adequate, robust vascular responses to passive and active movement represent two distinct components linked to normal, healthy cardiovascular function. Currently, limited research exists determining if these vascular responses are altered in premenopausal females (PMF) when compared across sex or menstrual cycle phase.

METHODS

Vascular responses to passive leg movement (PLM) and handgrip (HG) exercise were assessed in PMF ( n = 21) and age-matched men ( n = 21). A subset of PMF subjects ( n = 11) completed both assessments during the early and late follicular phase of their menstrual cycle. Microvascular function was assessed during PLM via changes in leg blood flow, and during HG exercise, via steady-state arm vascular conductance. Macrovascular (brachial artery [BA]) function was assessed during HG exercise via BA dilation responses as well as BA shear rate-dilation slopes.

RESULTS

Leg microvascular function, determined by PLM, was not different between sexes or across menstrual cycle phase. However, arm microvascular function, demonstrated by arm vascular conductance, was lower in PMF compared with men at rest and during HG exercise. Macrovascular function was not different between sexes or across menstrual cycle phase.

CONCLUSIONS

This study identified similar vascular function across sex and menstrual cycle phase seen in microvasculature of the leg and macrovascular (BA) of the arm. Although arm microvascular function was unaltered by menstrual cycle phase in PMF, it was revealed to be significantly lower when compared with age-matched men highlighting a sex difference in vascular/blood flow regulation during small muscle mass exercise.

Effects of biological sex and oral contraceptive pill use on cutaneous microvascular endothelial function and nitric oxide-dependent vasodilation in humans

The purpose of this study was to evaluate in vivo endothelial function and nitric oxide (NO)-dependent vasodilation between women in either menstrual or placebo pill phases of their respective hormonal exposure [either naturally cycling (NC) or using oral contraceptive pills (OCPs)] and men. A planned subgroup analysis was then completed to assess endothelial function and NO-dependent vasodilation between NC women, women using OCP, and men. Endothelium-dependent and NO-dependent vasodilation were assessed in the cutaneous microvasculature using laser-Doppler flowmetry, a rapid local heating protocol (39°C, 0.1 °C/s), and pharmacological perfusion through intradermal microdialysis fibers. Data are represented as means ± standard deviation. Men displayed greater endothelium-dependent vasodilation (plateau, men: 71 ± 16 vs. women: 52 ± 20%CVC_max, P < 0.01), but lower NO-dependent vasodilation (men: 52 ± 11 vs. women: 63 ± 17%NO, P = 0.05) compared with all women. Subgroup analysis revealed NC women had lower endothelium-dependent vasodilation (plateau, NC women: 48 ± 21%CVC_max, P = 0.01) but similar NO-dependent vasodilation (NC women: 52 ± 14%NO, P > 0.99), compared with men. Endothelium-dependent vasodilation did not differ between women using OCP and men (P = 0.12) or NC women (P = 0.64), but NO-dependent vasodilation was significantly greater in women using OCP (74 ± 11%NO) than both NC women and men (P < 0.01 for both). This study highlights the importance of directly quantifying NO-dependent vasodilation in cutaneous microvascular studies. This study also provides important implications for experimental design and data interpretation.NEW & NOTEWORTHY This study supports differences in microvascular endothelial function and nitric oxide (NO)-dependent vasodilation between women in low hormone phases of two hormonal exposures and men. However, when separated into subgroups of hormonal exposure, women during placebo pills of oral contraceptive pill (OCP) use have greater NO-dependent vasodilation than naturally cycling women in their menstrual phase and men. These data improve knowledge of sex differences and the effect of OCP use on microvascular endothelial function.

In vivo arterial stiffness, but not isolated artery endothelial function, varies with the mouse estrous cycle

With the increasing appreciation for sex as a biological variable and the inclusion of female mice in research, it is important to understand the influence of the estrous cycle on physiological function. Sex hormones are known to modulate vascular function, but the effects of the mouse estrous cycle phase on arterial stiffness, endothelial function, and arterial estrogen receptor expression remain unknown. In 23 female C57BL/6 mice (6 mo of age), we determined the estrous cycle stage via vaginal cytology and plasma hormone concentrations. Aortic stiffness, assessed by pulse wave velocity, was lower during the estrus phase compared with diestrus. In ex vivo assessment of isolated pressurized mesenteric and posterior cerebral arteries, the responses to acetylcholine, insulin, and sodium nitroprusside, as well as nitric oxide-mediated dilation, were not different between estrous cycle phases. In the aorta, expression of phosphorylated estrogen receptor-α was higher for mice in estrus compared with mice in proestrus. In the cerebral arteries, gene expression for estrogen receptor-β (Esr2) was lowest for mice in estrus compared with diestrus and proestrus. These results demonstrate that the estrus phase is associated with lower in vivo large artery stiffness in mice. In contrast, ex vivo resistance artery endothelial function is not different between estrous cycle phases. Estrogen receptor expression is modulated by the estrus cycle in an artery-dependent manner. These results suggest that the estrous cycle phase should be considered when measuring in vivo arterial stiffness in young female mice.NEW & NOTEWORTHY To design rigorous vascular research studies using young female rodents, the influence of the estrous cycle on vascular function must be known. We found that in vivo aortic stiffness was lower during estrus compared with the diestrus phase in female mice. In contrast, ex vivo mesenteric and cerebral artery endothelial function did not differ between estrous cycle stages. These results suggest that the estrous cycle stage should be accounted for when measuring in vivo arterial stiffness.

Chronic E-Cigarette Use Impairs Endothelial Function on the Physiological and Cellular Levels

BACKGROUND

The harmful vascular effects of smoking are well established, but the effects of chronic use of electronic cigarettes (e-cigarettes) on endothelial function are less understood. We hypothesized that e-cigarette use causes changes in blood milieu that impair endothelial function.

METHODS

Endothelial function was measured in chronic e-cigarette users, chronic cigarette smokers, and nonusers. We measured effects of participants' sera, or e-cigarette aerosol condensate, on NO and H2O2 release and cell permeability in cultured endothelial cells (ECs).

RESULTS

E-cigarette users and smokers had lower flow-mediated dilation (FMD) than nonusers. Sera from e-cigarette users and smokers reduced VEGF (vascular endothelial growth factor)-induced NO secretion by ECs relative to nonuser sera, without significant reduction in endothelial NO synthase mRNA or protein levels. E-cigarette user sera caused increased endothelial release of H2O2, and more permeability than nonuser sera. E-cigarette users and smokers exhibited changes in circulating biomarkers of inflammation, thrombosis, and cell adhesion relative to nonusers, but with distinct profiles. E-cigarette user sera had higher concentrations of the receptor for advanced glycation end products (RAGE) ligands S100A8 and HMGB1 (high mobility group box 1) than smoker and nonuser sera, and receptor for advanced glycation end product inhibition reduced permeability induced by e-cigarette user sera but did not affect NO production.

CONCLUSIONS

Chronic vaping and smoking both impair FMD and cause changes in the blood that inhibit endothelial NO release. Vaping, but not smoking, causes changes in the blood that increase microvascular endothelial permeability and may have a vaping-specific effect on intracellular oxidative state. Our results suggest a role for RAGE in e-cigarette-induced changes in endothelial function.

Cardiovascular deconditioning and impact of artificial gravity during 60-day head-down bed rest—Insights from 4D flow cardiac MRI

Microgravity has deleterious effects on the cardiovascular system. We evaluated some parameters of blood flow and vascular stiffness during 60 days of simulated microgravity in head-down tilt (HDT) bed rest. We also tested the hypothesis that daily exposure to 30 min of artificial gravity (1 g) would mitigate these adaptations. 24 healthy subjects (8 women) were evenly distributed in three groups: continuous artificial gravity, intermittent artificial gravity, or control. 4D flow cardiac MRI was acquired in horizontal position before (−9 days), during (5, 21, and 56 days), and after (+4 days) the HDT period. The false discovery rate was set at 0.05. The results are presented as median (first quartile; third quartile). No group or group × time differences were observed so the groups were combined. At the end of the HDT phase, we reported a decrease in the stroke volume allocated to the lower body (−30% [−35%; −22%]) and the upper body (−20% [−30%; +11%]), but in different proportions, reflected by an increased share of blood flow towards the upper body. The aortic pulse wave velocity increased (+16% [+9%; +25%]), and so did other markers of arterial stiffness (CAVI; CAVI0). In males, the time-averaged wall shear stress decreased (−13% [−17%; −5%]) and the relative residence time increased (+14% [+5%; +21%]), while these changes were not observed among females. Most of these parameters tended to or returned to baseline after 4 days of recovery. The effects of the artificial gravity countermeasure were not visible. We recommend increasing the load factor, the time of exposure, or combining it with physical exercise. The changes in blood flow confirmed the different adaptations occurring in the upper and lower body, with a larger share of blood volume dedicated to the upper body during (simulated) microgravity. The aorta appeared stiffer during the HDT phase, however all the changes remained subclinical and probably the sole consequence of reversible functional changes caused by reduced blood flow. Interestingly, some wall shear stress markers were more stable in females than in males. No permanent cardiovascular adaptations following 60 days of HDT bed rest were observed.

Effects of Diets Enriched with Conventional or High-Oleic Canola Oils on Vascular Endothelial Function: A Sub-Study of the Canola Oil Multi-Centre Intervention Trial 2 (COMIT-2), a Randomized Crossover Controlled Feeding Study

Partial replacement of saturated fatty acids (SFA) with unsaturated fatty acids is recommended to reduce cardiovascular disease (CVD) risk. Monounsaturated fatty acids (MUFA), including oleic acid, are associated with lower CVD risk. Measurement of flow-mediated dilation of the brachial artery (FMD) is the gold standard for measuring endothelial function and predicts CVD risk. This study examined the effect of partially replacing SFA with MUFA from conventional canola oil and high-oleic acid canola oil on FMD. Participants (n = 31) with an elevated waist circumference plus ≥1 additional metabolic syndrome criterion completed FMD measures as part of the Canola Oil Multi-Centre Intervention Trial 2 (COMIT-2), a multi-center, double-blind, three-period crossover, controlled feeding randomized trial. Diet periods were 6 weeks, separated by ≥4-week washouts. Experimental diets were provided during all feeding periods. Diets only differed by the fatty acid profile of the oils: canola oil (CO; 17.5% energy from MUFA, 9.2% polyunsaturated fatty acids (PUFA), 6.6% SFA), high-oleic acid canola oil (HOCO; 19.1% MUFA, 7.0% PUFA, 6.4% SFA), and a control oil blend (CON; 11% MUFA, 10% PUFA, 12% SFA). Multilevel models were used to examine the effect of the diets on FMD. No significant between-diet differences were observed for average brachial artery diameter (CO: 6.70 ± 0.15 mm, HOCO: 6.57 ± 0.15 mm, CON: 6.73 ± 0.14 mm; p = 0.72), peak brachial artery diameter (CO: 7.11 ± 0.15 mm, HOCO: 7.02 ± 0.15 mm, CON: 6.41 ± 0.48 mm; p = 0.80), or FMD (CO: 6.32 ± 0.51%, HOCO: 6.96 ± 0.49%, CON: 6.41 ± 0.48%; p = 0.81). Partial replacement of SFA with MUFA from CO and HOCO had no effect on FMD in participants with or at risk of metabolic syndrome.

Impact of prolonged sitting interruption strategies on shear rate, flow-mediated dilation and blood flow in adults: A systematic review and meta-analysis of randomized cross-over trials

Prolonged sitting has been shown to affect endothelial function. Strategies that promote interruption of sitting have shown varying results on the shear rate (SR), flow-mediated dilation (FMD) and blood flow (BF). Thus, we conducted a systematic review and meta-analysis to 1) increase the existing knowledge of the impact of sitting interruption in the prevention of endothelial dysfunction in adults and 2) determine the effect of the sitting interruption strategies on SR, FMD, BF. Literature search was carried out through 7 databases. A random effects model was used to provide the overall mean difference with a 95%CI, and forest plots were generated for pooled estimates of each study outcome. Assessment of biases was performed using ROB2 and considerations for crossover trials. Prolonged sitting interruption strategies showed a significant effect in increasing SR (MD: 7.58 s^-1; 95% CI: 3.00 to 12.17), FMD (MD: 1.74%; 95% CI: 0.55 to 2.93) and BF (MD: 12.08 ml/min; 95% CI: 7.61 to 16.55) when compared with the uninterrupted prolonged sitting condition. Prolonged sitting interruption strategies significantly increase SR, FMD and BF, therefore, they represent a considerable effective preventive method on endothelial dysfunction caused by acute exposure to uninterrupted prolonged sitting.

The acute effect of a laboratory shame induction protocol on endothelial function in young, healthy adults

NEW FINDINGS

What is the central question of this study? Shame is a form of social stress which involves internalizing social devaluations imposed by others. The aim of this study was to determine, for the first time, how acutely experiencing shame impacts endothelial function. What is the main finding and its importance? Brachial artery flow-mediated dilation, an index of endothelial function, was impaired following an intervention that acutely increased self reported shame. This occurred without increases in cortisol or tumor necrosis factor alpha receptor binding. Frequent or prolonged shame induced endothelial dysfunction could have important cardiovascular consequences.

ABSTRACT

Objective The objective of this study was to examine the impact of a shame induction protocol on endothelial function. Methods Fifteen participants (n = 7 men, n = 8 women) completed both a written shame induction and control protocol on two different experimental days. Pre- and post-protocol we assessed: 1) Endothelial function and arterial shear rate via a standard brachial artery reactive hyperemia flow-mediated dilation (FMD) test across two post-intervention time points (15 and 35-min post); 2) Perceived shame via the Experiential Shame Scale (ESS), and; 3) Cortisol and sTNFαRII (soluble tumor necrosis factor alpha receptor) through oral fluid analysis. Results Shame increased after the shame induction protocol (pre: 2.9±.6 vs. post: 3.7±.5, p<.001) but not the control protocol (pre: 3.0±.5 vs. post: 2.8±.5, p = .15) (protocol by time interaction: p<.001). When all three time points were included in the analysis, %FMD did not change over time. Considering only the lowest point, %FMD significantly decreased in response to the shame protocol (pre: 4.8±1.9 vs. post: 3.2±1.6, p<.001) but not the control protocol (4.2±1.8 vs. post: 3.8±1.5, p = .45) (protocol by time interaction: p = .035). Covariation of the shear rate stimulus for FMD did not alter the FMD results. When including both the control and shame protocol, but not the shame protocol alone, increased shame was significantly associated with decreased FMD (r = -.37, p<.046). There were no significant time by protocol interaction effects for cortisol or sTNFαRII. Conclusions Temporary increases in shame may cause transient endothelial dysfunction which, if chronically repeated, could manifest as reduced vasoprotection against atherosclerosis. This article is protected by copyright. All rights reserved.

Arterial stiffness and blood pressure are similar in naturally menstruating and oral contraceptive pill using women during the higher-hormone phases

NEW FINDINGS

What is the central question of this study? Are there differences in blood pressure, arterial stiffness and indices of pressure waveforms between young oral contraceptive pill using and naturally menstruating women during lower and higher hormone phases of their cycles? What is the main finding and its importance? Blood pressure, arterial stiffness and indices of pressure waveforms are influenced similarly by exogenous and endogenous hormones. However, lower levels of exogenous hormones moderately increase blood pressure among OCP.

ABSTRACT

Elevations in blood pressure (BP) are understood as having a bidirectional relationship with stiffening of central and peripheral arteries. Arterial stiffness is mitigated by oestrogen, which aides in arterial vasorelaxation. To evaluate whether BP, stiffness, and pressure waveforms were different between young healthy naturally menstruating (non-OCP) and oral contraceptive pill using women (OCP), we measured brachial and aortic BPs, carotid-to-femoral pulse wave velocity (cfPWV), carotid β-stiffness, elastic-modulus, central augmentation index (AIx and AIx75), and forward and backward pressure waveforms (Pf and Pb) in 22 women (22 (1) yr, OCP: n = 12). To assess phasic differences, women were studied during the early follicular (EF; ≤5 days of menstruation onset) and early luteal (EL; 4 (2) days post-ovulation) phases of non-OCP and compared to the placebo pill (PP; ≤5 days of onset) and active pill (AP; ≤5 days of highest-dose AP) phases of OCP. During the lower hormone phases, OCP have significantly higher brachial SBP (119.3 (8.3) vs. 110.2 (8.3) mmHg, P = 0.02) and aortic SBP (104.10 (7.44) vs. 96.80 (6.39) mmHg, P = 0.03) as compared to non-OCP; however, during the higher hormone phases, there are no differences in measures of brachial or aortic BP, arterial stiffness, or indices of BP waveforms between OCP and non-OCP (P≥0.05). In conclusion, exogenous and endogenous hormones have similar influences on BP and arterial stiffness; however, lower levels of exogenous hormones augment both central and peripheral BPs. This article is protected by copyright. All rights reserved.

Evidence of reduced peripheral microvascular function in young Black women across the menstrual cycle

Black women (BLW) have a higher prevalence of cardiovascular disease (CVD) morbidity and mortality compared with White women (WHW). A racial disparity in CVD risk has been identified early in life as young adult BLW demonstrate attenuated vascular function compared with WHW. Previous studies comparing vascular function between premenopausal WHW and BLW have been limited to the early follicular (EF) phase of the menstrual cycle, which may not reflect their vascular function during other menstrual phases. Therefore, we evaluated peripheral microvascular function in premenopausal WHW and BLW using passive leg movement (PLM) during three menstrual phases: EF, ovulation (OV), and mid-luteal (ML). We hypothesized that microvascular function would be augmented during the OV and ML phases compared with the EF phase in both groups, but would be attenuated in BLW compared with WHW at all three phases. PLM was performed on 26 apparently healthy premenopausal women not using hormonal contraceptives: 15 WHW (23 ± 3 yr), 11 BLW (24 ± 5 yr). There was a main effect of race on the overall change in leg blood flow (ΔLBF) (P = 0.01) and leg blood flow area under the curve (LBF AUC) (P = 0.02), such that LBF was lower in BLW. However, there was no effect of phase on ΔLBF (P = 0.69) or LBF AUC (P = 0.65), nor an interaction between race and phase on ΔLBF (P = 0.37) or LBF AUC (P = 0.75). Despite peripheral microvascular function being unchanged across the menstrual cycle, a racial disparity was apparent as microvascular function was attenuated in BLW compared with WHW across the menstrual cycle.NEW & NOTEWORTHY This is the first study to compare peripheral microvascular function between young, otherwise healthy Black women and White women at multiple phases of the menstrual cycle. Our novel findings demonstrate a significant effect of race on peripheral microvascular function such that Black women exhibit significant attenuations in microvascular function across the menstrual cycle compared with White women.

Endothelial function and concentrations of high-sensitivity C-reactive protein, interleukin-6, and tumor necrosis factor-alpha during a long agonist IVF protocol

We examined possible changes in endothelial function during a long agonist in vitro fertilization (IVF) protocol. We measured flow-mediated dilatation (FMD) and FMD percent (FMD%) from the brachial artery and plasma levels of high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-〈). We studied longitudinally three time points in 27 women undergoing a long agonist IVF treatment at Kuopio University Hospital. The first visit was at the beginning of their period (low estradiol). The other two visits were during gonadotrophin-releasing hormone (GnRH) analog downregulation (low estradiol) and at the end of follicle-stimulating hormone (FSH) stimulation (high estradiol). The first visit was used as the reference, and the women served as their own controls. During the stimulation protocol, FMD and FMD% remained. Toward the end of stimulation, hsCRP (P = 0.003), IL-6 (P = 0.04), and TNF-〈 (P = 0.008) concentrations all decreased, while estradiol levels increased (P < 0.001). Correlations between estradiol and proinflammatory factors or FMD were, however, non-significant. The only significant correlation appeared between FMD% and hsCRP at Visit 2 (r = 0.485, P = 0.01). In conclusion, IVF stimulation promoted no change in endothelial function, whereas hsCRP, IL-6, and TNF-〈 decreased. These findings indicate that estrogen may improve the cytokine profile among healthy women undergoing IVF, but this is not reflected in endothelial function.

Does aerobic fitness impact prolonged sitting-induced popliteal artery endothelial dysfunction?

PURPOSE

Acute prolonged bouts of sitting reduce popliteal artery blood flow and flow-mediated dilation (FMD). Individuals with higher aerobic fitness have enhanced popliteal FMD. Conflicting evidence regarding whether more aerobically fit individuals are protected from the negative impacts of sitting on popliteal endothelial function in male-dominated studies have been reported. We further explored the relationship between aerobic fitness and sitting-induced impairments in popliteal blood flow and FMD in a more sex-balanced cohort.

METHODS

Relative peak oxygen consumption (V̇O₂peak) was assessed using a cycling-based incremental test in 21 healthy adults (eight males; 23 ± 2 years; 23.9 ± 2.9 kg/m²). Popliteal blood flow and relative FMD (%) were measured via duplex ultrasonography before and after 3 h of uninterrupted sitting. Pearson correlations were performed separately between V̇O₂peak versus pre-sitting and sitting-induced reductions in popliteal outcomes.

RESULTS

Aerobic fitness (41.0 ± 9.7 ml/kg/min) was positively correlated with pre-sitting popliteal blood flow (65 ± 23 mL/min; R = 0.59, P = 0.005) and relative FMD (4.2 ± 1.5%; R = 0.49, P = 0.03). As expected, sitting reduced resting blood flow (19 ± 11 mL/min) and FMD (1.9 ± 0.7%) (both, P < 0.001). V̇O₂peak was inversely related to sitting-induced declines in blood flow (Δ-46 ± 23 mL/min; R = - 0.71, P < 0.001) and FMD (Δ-2.4 ± 1.5%; R = - 0.51, P = 0.02).

CONCLUSIONS

Although higher aerobic fitness was associated with more favorable popliteal endothelial-dependent vasodilator responses, it also corresponded with larger sitting-induced impairments in FMD. This suggests that being more aerobically fit does not protect against sitting-induced vascular endothelial dysfunction. As such, all young adults should minimize habitual prolonged sedentary bouts, regardless of their aerobic fitness level.

Changes in vascular function and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight

This study aimed to evaluate vascular function changes and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight. This prospective study performed in pregnant (PG) women and after delivery (not pregnant: NPG) evaluated the endothelial function (EF) and arterial stiffness (AS) by a non-invasive method. We evaluated the heart rate variability (HRV), parasympathetic nervous system (PNS), sympathetic nervous system (SNS) indexes by electrocardiogram (5 min) and the urinary nitrite excretion (NOx). PG increased EF and NOx and decreased AS and HRV. PG decreased the PNS index and augmented the SNS index. The new-born weight positively correlated with the PNS index (Pearson's r: 0.4291; p<.05), NOx, HRV and negatively correlated with AS. In summary, in pregnancy, although haemodynamically, the SNS activation plays a compensatory role, the low rates of PNS inhibition are essential to ensure normal foetal growth.Impact StatementWhat is already known on this subject? In pregnancy, there are adaptive physiological changes in the cardiovascular system that include increases of EF and decreases AS with an SNS activation. The study of HRV lets to predict the SNS and PNS balance and how they affect blood pressure and vascular function.What the results of this study add? Although it is known that SNS activation plays a compensatory role in healthy pregnancy, this study adds the critical role of PNS. Early in pregnancy, the low rates of PNS inhibition are essential to ensure normal foetal growth.What the implications are of these findings for clinical practice and/or further research? The present results show a potential predictive value of SNS and PNS activity early in pregnancy. It will provide valuable information not only on the pregnant woman's vascular function but also on the new-born weight.

Impact of hesperidin in 100% orange juice on chronic disease biomarkers: A narrative systematic review and gap analysis

Hesperidin in orange juice may affect chronic disease biomarkers. This narrative systematic review aimed to determine appropriate recommendations toward the dose and frequency of hesperidin consumption from 100% orange juice and conduct a gap analysis. The Preferred Reporting Items for Systematic Review and Meta-analysis was conducted to identify articles through September 2020, utilizing four databases: Pub-Med Central, Agricola, Embase, and MEDLINE. Twenty articles met the inclusion criteria. Results showed that overall effect sizes from the studies were considerably weak. Although higher frequencies, doses, and concentration of hesperidin in 100% orange juice had an impact on global cognitive function, cardiac, insulin, inflammatory, antioxidant/phenolic, and oxidative stress outcomes compared to lower frequencies, doses, and concentration of hesperidin. A gap analysis demonstrated there was a variability in dose and frequency of OJ and hesperidin, diet, genetics, and evaluation measures, which made the role of hesperidin in 100% OJ on chronic diseases unclear. This review revealed a trend toward improving chronic disease biomarkers following consumption of hesperidin in 100% orange juice. Steps can be taken in future research to improve the consistency of clinical study designs, methodology and outcomes.

Individual variation of follicular phase changes in endothelial function across two menstrual cycles

NEW FINDINGS

What is the central question of this study? The purpose of this study was to determine intra-individual reproducibility of follicular phase changes in endothelial function (flow-mediated dilatation) over two menstrual cycles in healthy, premenopausal women. What is the main finding and its importance? Phase changes in endothelial function were not consistent at the individual level across two menstrual cycles, which challenges the utility of interpreting individual responses over one cycle.

ABSTRACT

Evidence regarding the impact of menstrual phase on endothelial function is conflicting, and studies to date have examined responses only over a single cycle. It is unknown whether the observed inter-individual variability of phase changes in endothelial function reflects stable, inter-individual differences in responses to oestrogen (E₂ ; a primary female sex hormone). The purpose of this study was to examine changes in endothelial function from the early follicular (EF; low-E₂ ) phase to the late follicular (LF; high-E₂ ) phase over two consecutive cycles. Fourteen healthy, regularly menstruating women [22 ± 3 years of age (mean ± SD)] participated in four visits (EF_Visit 1 , LF_Visit 2 , EF_Visit 3 and LF_Visit 4 ) over two cycles. Ovulation testing was used to determine the time between the LF visit and ovulation. During each visit, endothelial function [brachial artery flow-mediated dilatation (FMD)], E₂ and progesterone were assessed. At the group level, there was no impact of phase or cycle on FMD (P = 0.48 and P = 0.65, respectively). The phase change in FMD in cycle 1 did not predict the phase change in cycle 2 (r = 0.03, P = 0.92). Using threshold-based classification (2 × typical error threshold), four of 14 participants (29%) exhibited directionally consistent phase changes in FMD across cycles. Oestrogen was not correlated between cycles, and this might have contributed to variability in the FMD response. The intra-individual variability in follicular fluctuation in FMD between menstrual cycles challenges the utility of interpreting individual responses to phase over a single menstrual cycle.

The Effects of Acute Exposure to Prolonged Sitting, With and Without Interruption, on Vascular Function Among Adults: A Meta-analysis

BACKGROUND

Exposure to acute prolonged sitting can result in vascular dysfunction, particularly within the legs. This vascular dysfunction, assessed using flow-mediated dilation (FMD), is likely the consequence of decreased blood flow-induced shear stress. With mixed success, several sitting interruption strategies have been trialled to preserve vascular function.

OBJECTIVES

The objectives of this meta-analysis were to (1) assess the effects of acute prolonged sitting exposure on vascular function in the upper- and lower-limb arteries, and (2) evaluate the effectiveness of sitting interruption strategies in preserving vascular function. Sub-group analyses were conducted to determine whether artery location or interruption modality explain heterogeneity.

DATA SOURCES

Electronic databases (PubMed, Web of Science, SPORTDiscus, and Google Scholar) were searched from inception to January 2020. Reference lists of eligible studies and relevant reviews were also checked.

STUDY SELECTION

Inclusion criteria for objective (1) were: (i) FMD% was assessed pre- and post-sitting; (ii) studies were either randomised-controlled, randomised-crossover, or quasi-experimental trials; (iii) the sitting period was ≥ 1 h; and (iv) participants were healthy non-smoking adults (≥ 18 years), and free of vascular-acting medication and disease at the time of testing. Additional inclusion criteria for objective (2) were: (i) the interruption strategy must have been during the sitting period; (ii) there was a control (uninterrupted sitting) group/arm; and (iii) the interruption strategy must have involved the participants actively moving their lower- or upper-limbs.

APPRAISAL AND SYNTHESIS METHODS

One thousand eight hundred and two articles were identified, of which 17 (22 trials, n = 269) met inclusion criteria for objective (1). Of those 17 articles, 6 studies (9 trials, n = 127) met the inclusion criteria for objective (2). Weighted mean differences (WMD), 95% confidence intervals (95% CI), and standardised mean difference (SMD) were calculated for all trials using random-effects meta-analysis modelling. SMD was used to determine the magnitude of effect, where < 0.2, 0.2, 0.5, and 0.8 was defined as trivial, small, moderate, and large respectively.

RESULTS

(1) Random-effects modelling showed uninterrupted bouts of prolonged sitting resulted in a significant decrease in FMD% (WMD = - 2.12%, 95% CI - 2.66 to - 1.59, SMD = 0.84). Subgroup analysis revealed reductions in lower- but not upper-limb FMD%. (2) Random-effects modelling showed that interrupting bouts of sitting resulted in a significantly higher FMD% compared to uninterrupted sitting (WMD = 1.91%, 95% CI 0.40 to 3.42, SMD = 0.57). Subgroup analyses failed to identify an optimum interruption strategy but revealed moderate non-significant effects for aerobic interventions (WMD = 2.17%, 95% CI - 0.34 to 4.67, SMD = 0.69) and simple resistance activities (WMD = 2.40%, 95% CI - 0.08 to 4.88, SMD = 0.55) and a trivial effect for standing interruptions (WMD = 0.24%, 95% CI - 0.90 to 1.38, SMD = 0.16).

CONCLUSIONS

Exposure to acute prolonged sitting leads to significant vascular dysfunction in arteries of the lower, but not upper, limbs. The limited available data indicate that vascular dysfunction can be prevented by regularly interrupting sitting, particularly with aerobic or simple resistance activities.

Impact of acute high-intensity interval exercise on plasma pentraxin 3 and endothelial function in obese individuals-a pilot study

PURPOSE

Pentraxin 3 (PTX3) has been shown to be a predictor of endothelial dysfunction in patients with increased risk of cardiovascular disease (CVD) (e.g., obesity). Circulating PTX3 concentrations are dysregulated in obese individuals and are elevated following acute aerobic exercise. High-intensity interval exercise (HIIE) has been demonstrated to be as effective as continuous moderate-intensity exercise in improving endothelial function, as indicated by brachial artery flow-mediated dilation (BAFMD), in patients with CVD. Therefore, the purpose of this study was to examine the effect of acute HIIE on plasma PTX3 and BAFMD responses in obese individuals.

METHODS

Eight obese and six normal-weight young males participated in acute HIIE (4 intervals of 4 min at 80-90% of VO_2max; 3 min of active recovery at 50-60% VO_2max). Plasma PTX3 and BAFMD were measured prior to, immediately following exercise, and one and 2 hours into recovery.

RESULTS

Plasma PTX3 concentrations significantly increased following HIIE, yet the PTX3 response to HIIE was significantly blunted in obese compared to normal-weight participants. While the kinetic responses of BAFMD were also significantly different in obese compared to normal-weight participants, similar increases above the baseline were observed 2 hours into recovery in both groups. Finally, plasma PTX3 concentrations were not associated with BAFMD at baseline or in response to HIIE.

CONCLUSION

The utilization of HIIE may serve as a time-efficient exercise prescription strategy to transiently improve endothelial function, independent of elevated plasma PTX3 concentrations, in obese individuals.

Ascorbic Acid Prevents Vascular Endothelial Dysfunction Induced by Electronic Hookah (Waterpipe) Vaping

Background Electronic hookah (e-hookah) vaping has increased in popularity among youth, who endorse unsubstantiated claims that flavored aerosol is detoxified as it passes through water. However, e-hookahs deliver nicotine by creating an aerosol of fine and ultrafine particles and other oxidants that may reduce the bioavailability of nitric oxide and impair endothelial function secondary to formation of oxygen-derived free radicals. Methods and Results We examined the acute effects of e-hookah vaping on endothelial function, and the extent to which increased oxidative stress contributes to the vaping-induced vascular impairment. Twenty-six healthy young adult habitual hookah smokers were invited to vape a 30-minute e-hookah session to evaluate the impact on endothelial function measured by brachial artery flow-mediated dilation (FMD). To test for oxidative stress mediation, plasma total antioxidant capacity levels were measured and the effect of e-hookah vaping on FMD was examined before and after intravenous infusion of the antioxidant ascorbic acid (n=11). Plasma nicotine and exhaled carbon monoxide levels were measured before and after the vaping session. Measurements were performed before and after sham-vaping control experiments (n=10). E-hookah vaping, which increased plasma nicotine (+4.93±0.92 ng/mL, P<0.001; mean±SE) with no changes in exhaled carbon monoxide (-0.15±0.17 ppm; P=0.479), increased mean arterial pressure (11±1 mm Hg, P<0.001) and acutely decreased FMD from 5.79±0.58% to 4.39±0.46% (P<0.001). Ascorbic acid infusion, which increased plasma total antioxidant capacity 5-fold, increased FMD at baseline (5.98±0.66% versus 9.46±0.87%, P<0.001), and prevented the acute FMD impairment by e-hookah vaping (9.46±0.87% versus 8.74±0.84%, P=0.002). All parameters were unchanged during sham studies. Conclusions E-hookah vaping has adverse effects on vascular function, likely mediated by oxidative stress, which overtime could accelerate development and progression of cardiovascular disease. Registration URL: https://ClinicalTrials.gov. Unique identifier: NCT03690427.

The effects of prolonged sitting, prolonged standing, and activity breaks on vascular function, and postprandial glucose and insulin responses: A randomised crossover trial

The objective of this study was to compare acute effects of prolonged sitting, prolonged standing and sitting interrupted with regular activity breaks on vascular function and postprandial glucose metabolism. In a randomized cross-over trial, 18 adults completed: 1. Prolonged Sitting; 2. Prolonged Standing and 3. Sitting with 2-min walking (5 km/h, 10% incline) every 30 min (Regular Activity Breaks). Flow mediated dilation (FMD) was measured in the popliteal artery at baseline and 6 h. Popliteal artery hemodynamics, and postprandial plasma glucose and insulin were measured over 6 h. Neither raw nor allometrically-scaled FMD showed an intervention effect (p = 0.285 and 0.159 respectively). Compared to Prolonged Sitting, Regular Activity Breaks increased blood flow (overall effect of intervention p<0.001; difference = 80%; 95% CI 34 to 125%; p = 0.001) and net shear rate (overall effect of intervention p<0.001; difference = 72%; 95% CI 30 to 114%; p = 0.001) at 60 min. These differences were then maintained for the entire 6 h. Prolonged Standing increased blood flow at 60 min only (overall effect of intervention p<0.001; difference = 62%; 95% CI 28 to 97%; p = 0.001). Regular Activity Breaks decreased insulin incremental area under the curve (iAUC) when compared to both Prolonged Sitting (overall effect of intervention P = 0.001; difference = 28%; 95% CI 14 to 38%; p<0.01) and Prolonged Standing (difference = 19%; 95% CI 4 to 32%, p = 0.015). There was no intervention effect on glucose iAUC or total AUC (p = 0.254 and 0.450, respectively). In normal-weight participants, Regular Activity Breaks induce increases in blood flow, shear stress and improvements in postprandial metabolism that are associated with beneficial adaptations. Physical activity and sedentary behaviour messages should perhaps focus more on the importance of frequent movement rather than simply replacing sitting with standing.

Influence of prostaglandins and endothelial-derived hyperpolarizing factors on brachial and popliteal endothelial-dependent function in young adults

Heterogeneous flow-mediated dilation (FMD) and low-flow-mediated constriction (L-FMC) responses have been reported between upper- and lower-limb arteries. Radial artery L-FMC, but not FMD, responses are blunted when endothelial-derived hyperpolarizing factors (EDHFs) or prostaglandin production is inhibited in young adults. However, it is unknown if these mechanisms similarly impact endothelial-dependent responses in the brachial (BA) and popliteal (POP) arteries. We tested whether BA- and POP-L-FMC and FMD would be influenced by independent EDHF and prostaglandin inhibition. Eighteen participants (23 ± 3 yr; 6♀) completed three randomized and double-blinded ultrasound assessments following ingestion of an opaque capsule containing maltodextrin (control), 150 mg of fluconazole (EDHF inhibition), or 500 mg of aspirin (prostaglandin inhibition). POP resting diameter was reduced following fluconazole administration (6.13 ± 0.63 mm vs. 6.19 ± 0.65 mm in control, P = 0.03). Compared with control, fluconazole also blunted the relative L-FMC responses in both the BA (-2.1 ± 0.8% vs. -0.8 ± 1.0%, P = 0.001) and POP (-1.7 ± 1.1% vs. -0.8 ± 0.9%, P = 0.009). In contrast, aspirin did not impact either the BA (-1.9 ± 0.7%) or POP-L-FMC (-1.3 ± 0.6%) responses (both, P > 0.35). The FMD response was unchanged following fluconazole or aspirin administration in either artery (both, P > 0.36). Our findings demonstrate that EDHF mediates L-FMC responses in both the brachial and popliteal arteries. Complementary to the nitric oxide-mediated FMD response, L-FMC appears to provide information regarding the EDHF pathway. Future research should uncover if these mechanisms impact older adults and/or patient populations characterized by vascular endothelial dysfunction associated with low aerobic fitness and habitual physical activity levels.NEW & NOTEWORTHY We compared changes in upper- and lower-limb artery endothelial-dependent vasodilatory and vasoconstrictor responses between control, prostaglandin inhibition, and endothelial-derived hyperpolarizing factor inhibition conditions. Neither prostaglandins nor endothelial-derived hyperpolarizing factor influenced flow-mediated dilation responses in either the brachial or popliteal artery. In contrast, endothelial-derived hyperpolarizing factor, but not prostaglandins, reduced resting brachial artery blood flow and shear rate and resting popliteal artery diameter, as well as low-flow-mediated constriction responses in both the popliteal and brachial arteries.

Associations of Sex Hormones and Hormonal Status With Arterial Stiffness in a Female Sample From Reproductive Years to Menopause

OBJECTIVE

Loss of sex hormones has been suggested to underlie menopause-associated increment in cardiovascular risk. We investigated associations of sex hormones with arterial stiffness in 19-58-years-old women. We also studied associations of specific hormonal stages, including natural menstrual cycle, cycle with combined oral contraceptives (COC) and menopausal status with or without hormone therapy (HT), with arterial stiffness.

METHODS

This study includes repeated measurements of 65 healthy women representing reproductive (n=16 natural, n=10 COC-users) and menopause (n=5 perimenopausal, n=26 postmenopausal, n=8 HT-users) stages. Arterial stiffness outcomes were aortic pulse wave velocity (PWVao) and augmentation index (AIx%) assessed using Arteriograph-device. Generalized estimating equation models were constructed to investigate associations of each hormone (wide age-range models) or hormonal stage (age-group focused models) with arterial stiffness. PWVao models with cross-sectional approach, were adjusted for age, relative fitness, fat mass and mean arterial pressure, while models with longitudinal approach were adjusted for mean arterial pressure. AIx% models used the same approach for adjustments and were also adjusted for heart rate.

RESULTS

Negative and positive associations with arterial stiffness variables were observed for estradiol and follicle-stimulating hormone, respectively, until adjustment for confounding effect of age. In naturally menstruating women, AIx% was higher at ovulation (B=3.63, p<0.001) compared to the early follicular phase. In COC-users, PWVao was lower during active (B=-0.33 - -0.57, p<0.05) than inactive pills. In menopausal women, HT-users had higher PWVao (B=1.43, p=0.03) than postmenopausal non-HT-users.

CONCLUSIONS

When using wide age-range assessments covering reproductive to menopausal lifespan it is difficult to differentiate age- and hormone-mediated associations, because age-mediated influence on arterial stiffness seemed to overrule potential hormone-mediated influences. However, hormonal status associated differentially with arterial stiffness in age-group focused analyses. Thus, the role of sex hormones cannot be excluded. Further research is warranted to resolve potential hormone-mediated mechanisms affecting arterial elasticity.

Effects of menstrual cycle and menopause on internal carotid artery shear-mediated dilation in women

This study aimed to elucidate the effects of change in estrogen during the menstrual cycle and menopause on shear-mediated dilation of the internal carotid artery (ICA), a potential index of cerebrovascular endothelial function. Shear-mediated dilation of the ICA and serum estradiol were measured in 11 premenopausal (Pre-M, 21 ± 1 yr), 13 perimenopausal (Peri-M, 49 ± 2 yr), and 10 postmenopausal (Post-M, 65 ± 7 yr) women. Measurements were made twice within the Pre-M group at their early follicular (EF, lower estradiol) and late follicular (LF, higher estradiol) phases. Shear-mediated dilation was induced by 3 min of hypercapnia (target P_ETCO₂ + 10 mmHg from individual baseline) and was calculated as the percent rise in peak diameter relative to baseline diameter. ICA diameter and blood velocity were simultaneously measured by Doppler ultrasound. In Pre-M, shear-mediated dilation was higher during the LF phase than during the EF phase (P < 0.01). Comparing all groups, shear-mediated dilation was reduced across the menopausal transition (P < 0.01), and Pre-M during the LF phase showed the highest value (8.9 ± 1.4%) compared with other groups (Pre-M in EF, 6.4 ± 1.1%; Peri-M, 5.5 ± 1.3%; Post-M, 5.2 ± 1.9%, P < 0.05 for all). Shear-mediated dilation was positively correlated with serum estradiol even after adjustment of age (P < 0.01, r = 0.55, age-adjusted; P = 0.02, r = 0.35). Collectively, these data indicate that controlling the menstrual cycle phase is necessary for the cross-sectional assessments of shear-mediated dilation of the ICA in premenopausal women. Moreover, current findings suggest that a decline in cerebrovascular endothelial function may be partly related to the reduced circulating estrogen levels in peri- and postmenopausal women.NEW & NOTEWORTHY The present study evaluated the effects of the menstrual cycle and menopause stages on the shear-mediated dilation of the ICA, a potential index of cerebrovascular endothelial function, in pre-, peri-, and postmenopausal women. Shear-mediated dilation of the ICA was increased from the low- to high-estradiol phases in naturally cycling premenopausal women and was reduced with advancing menopause stages. Furthermore, lower estradiol was associated with reduced shear-mediated dilation of the ICA, independent of age.

Endothelial function is preserved in light to moderate alcohol drinkers but is impaired in heavy drinkers in women: Flow-mediated Dilation Japan (FMD-J) study

Light to moderate alcohol consumption has protective effects on all-cause death and coronary artery disease in women. It is thought that light to moderate alcohol consumption has a beneficial effect on vascular function in women. We measured flow-mediated vasodilation (FMD) in 702 women aged 17-86 years who provided information on alcohol consumption. We divided the subjects into four groups: non-drinkers (0 g/week), light drinkers (>0 to 140 g/week), moderate drinkers (>140 to 280 g/week) and heavy drinkers (>280 g/week). There was no significant difference in FMD among the four groups. Multivariate regression analysis revealed that alcohol consumption in non-drinkers and light drinkers was not an independent predictor of FMD (β = -0.001, P = 0.98). We compared 50 moderate drinkers and 50 non-drinkers matched for age and medical histories and 22 heavy drinkers and 22 non-drinkers in matched pair analysis. There was no significant difference in FMD between moderate drinkers and non-drinkers (8.2±4.3% vs. 8.1±3.5, P = 0.91), while FMD in heavy drinkers was significantly lower than that in non-drinkers (5.9±2.5% vs. 8.9±3.5%, P = 0.002). These findings suggest that heavy alcohol consumption is associated with endothelial dysfunction but that light to moderate alcohol consumption is not associated with endothelial dysfunction in women. Clinical trial registration information This study was approved by principal authorities and ethical issues in Japan (University Hospital Medical Information Network UMIN000012952, 01/12/2009). www.umin.ac.jp/.

Impact of the menstrual cycle on peripheral vascular function in premenopausal women: systematic review and meta-analysis

Fluctuations in endogenous hormones estrogen and progesterone during the menstrual cycle may offer vasoprotection for endothelial and smooth muscle (VSM) function. While numerous studies have been published, the results are conflicting, leaving our understanding of the impact of the menstrual cycle on vascular function unclear. The purpose of this systematic review and meta-analysis was to consolidate available research exploring the role of the menstrual cycle on peripheral vascular function. A systematic search of MEDLINE, Web of Science, and EMBASE was performed for articles evaluating peripheral endothelial and VSM function across the natural menstrual cycle: early follicular (EF) phase versus late follicular (LF), early luteal, mid luteal, or late luteal. A meta-analysis examined the effect of the menstrual cycle on the standardized mean difference (SMD) of the outcome measures. Analysis from 30 studies (n = 1,363 women) observed a "very low" certainty of evidence that endothelial function increased in the LF phase (SMD: 0.45, P = 0.0001), with differences observed in the macrovasculature but not in the microvasculature (SMD: 0.57, P = 0.0003, I2 = 84%; SMD: 0.21, P = 0.17, I2 = 34%, respectively). However, these results are partially explained by differences in flow-mediated dilation [e.g., discrete (SMD: 0.86, P = 0.001) vs. continuous peak diameter assessment (SMD: 0.25, P = 0.30)] and/or menstrual cycle phase methodologies. There was a "very low" certainty that endothelial function was largely unchanged in the luteal phases, and VSM was unchanged across the cycle. The menstrual cycle appears to have a small effect on macrovascular endothelial function but not on microvascular or VSM function; however, these results can be partially attributed to methodological differences.

Female Sex Hormone Effects on the Vasculature: Considering the Validity of Restricting Study Inclusion to Low-Hormone Phases

Many studies of vascular function limit the testing of premenopausal female participants to periods when female sex hormones, either endogenous or exogenous, are at their lowest concentration. This practice, when not part of the specific research question, may limit data surrounding the predominant physiological state of premenopausal females and pose a threat to external validity. In this Perspective, we briefly review the literature on the effect of female sex hormones on vascular function and discuss when limiting experimental testing to a certain phase of the menstrual cycle (MC) or oral contraceptive (OC) use may be appropriate. The goal of this Perspective is to open a dialog that may enhance data validity and the overall understanding of vascular function in premenopausal females.

Importance of Sensitive Vascular Measurements for Evaluating Effects of Lifestyle in Premenopausal Women

Premenopausal women generally have a favorable cardiovascular risk profile, owing to young age and the protective effects of estrogen. Rates of hypertension and more advanced cardiovascular disease (CVD) are low in premenopausal women. A large body of epidemiological evidence has shown that lifestyle behaviors in midlife, i.e., cardiorespiratory fitness, physical activity, and healthy diet, are associated with lower risk of overt CVD and adverse cardiovascular outcomes in the future for men and women. Despite differences in future cardiovascular risk, brachial blood pressures might be similar between premenopausal women with favorable vs. unfavorable levels of lifestyle behaviors in early-to-mid-life. Here we make the case for deeper phenotyping by means of vascular function measurements, such as arterial stiffness, augmentation index, and endothelial function, to identify potential mechanistic pathways linking lifestyle behaviors in early-to-mid-adulthood with lifelong CVD risk in women. We describe considerations for vascular function measurement in premenopausal women and opportunities for investigators to fill in knowledge gaps to further our understanding of CVD risk assessment and CVD progression in premenopausal women.

Effects of short-term consumption of strawberry powder on select parameters of vascular health in adolescent males

Cardiovascular disease is a leading cause of death in the United States and much of the developed world, costing billions of dollars in lost work time, lower productivity and high health care expenditures. Research on foods and bioactive food components that have cardioprotective benefits may provide new insights as to how modest changes in one's diet may result in a reduced risk of vascular disease. In intervention trials, the consumption of strawberries, either fresh or freeze-dried, has been reported to improve select markers of cardiovascular health, including improved lipid profiles, microvascular function, and platelet reactivity. Consistent with the above, epidemiological studies suggest beneficial effects of strawberries on vascular function. Preliminary studies on the effects of freeze-dried strawberry powder on vascular health are reviewed in the current paper.

Popliteal flow-mediated dilatory responses to an acute bout of prolonged sitting between earlier and later phases of natural menstrual and oral contraceptive pill cycles

We compared changes in popliteal artery endothelial function to a 3-h bout of sitting in females across their natural menstrual or oral contraceptive pill cycles. Pre-sitting endothelial-dependent vasodilation was greater in females who naturally menstruate during the later versus earlier phase but unchanged among contraceptive pill phases. Neither menstrual nor oral contraceptive pill phases attenuated the robust decline in conduit artery health following an acute period of uninterrupted sitting in young females.

The Effects of a Simulated Workday of Prolonged Sitting on Seated versus Supine Blood Pressure and Pulse Wave Velocity in Adults with Overweight/Obesity and Elevated Blood Pressure

We evaluated the effects of a simulated workday of prolonged sitting on blood pressure (BP) and pulse wave velocity (PWV) and examined whether posture (seated vs. supine) affected responses. Participants (n = 25) were adults, with overweight/obesity and elevated BP, and performed seated desk work for 7.5 h. BP and PWV were measured in seated and supine postures at baseline (7:15 a.m.), midday (12:05 p.m.), and afternoon (4:45 p.m.). Generalized linear mixed models evaluated the effects of prolonged sitting on BP and PWV within each posture and interactions by posture and sex. In the recommended postures, seated BP and supine carotid-femoral pulse wave velocity (cfPWV) and carotid-ankle pulse wave velocity (caPWV), but not carotid-radial pulse wave velocity (crPWV), significantly increased over the simulated seated workday (all p < 0.05; effect sizes [d] ranged from 0.25 to 0.44). Whilst no posture-by-time interactions were observed (p > 0.05), BP, caPWV, and crPWV were higher when seated versus supine (main effects of posture p < 0.05; d ranged from 0.30 to 1.04). Exploratory analysis revealed that females had greater seated BP responses (p for interaction <0.05); seated PWV and supine BP and PWV responses were similar by sex (p for interaction >0.05). A simulated workday of prolonged sitting increased seated BP and supine cfPWV and caPWV, and posture minimally influenced these responses. These results add to the evidence suggesting a deleterious effect of prolonged sitting on cardiovascular health.

Dietary Nitrate Supplementation and Exercise-Related Performance

Over the last decade, there has been a growing interest in the utility of nitrate (NO3^-) supplementation to improve exercise-related performance. After consumption, dietary NO3^- can be reduced to nitric oxide, a free radical gas involved in numerous physiological actions including blood vessel vasodilation, mitochondrial respiration, and skeletal muscle contractile function. Emerging evidence indicates that dietary NO3^- supplementation has a small but nevertheless significant beneficial effect on endurance performance through the combined effects of enhanced tissue oxygenation and metabolic efficiency in active skeletal muscle. There is further evidence to suggest that dietary NO3^- exerts a direct influence on contractile mechanisms within the skeletal muscle through alterations in calcium availability and sensitivity. Response heterogeneity and sizeable variability in the nitrate content of beetroot juice products influence the effectiveness of dietary NO3^- for exercise performance, and so dosing and product quality, as well as training history, sex, and individual-specific characteristics, should be considered.

Blood Orange Juice Consumption Increases Flow-Mediated Dilation in Adults with Overweight and Obesity: A Randomized Controlled Trial

BACKGROUND

Epidemiological studies have indicated an inverse association between citrus fruit consumption and cardiovascular disease (CVD) risk. There is, however, a paucity of data concerning effects of blood orange juice (BOJ) intake on endothelial function and cardiovascular risk biomarkers.

OBJECTIVES

We examined short-term effects of BOJ on endothelial function, blood pressure, lipid profile, and inflammatory markers in healthy participants of European origin who were overweight or obese.

METHODS

In a randomized, controlled, single-blind, crossover trial, 15 men and women (age: 28.7 ± 6.5 y; BMI: 28.3 ± 3.1 kg/m2) consumed BOJ or a sugar-matched control drink (CD) (200 mL twice daily) for 2 wk with a washout period of 1 wk. Endothelial function, measured as flow-mediated dilation (FMD) (primary outcome), and the secondary outcomes blood pressure, anthropometric measures, lipid profile, inflammatory markers, markers of vasodilation and vasoconstriction, and urinary flavanone metabolites were evaluated prior to and at the end of each treatment period following an overnight fast. Changes between treatments over time were assessed using repeated-measures ANOVA.

RESULTS

The results demonstrate a significant increase in FMD following BOJ consumption (pre: 8.15% ± 2.92%; post: 10.2% ± 3.31%; P = 0.002) compared with CD (pre: 8.11% ± 2.52%; post: 7.77% ± 2.43%; time × treatment interaction: P = 0.001). Concurrent significant increases in urinary hesperetin-3'-glucuronide and hesperetin-7-glucuronide were observed following BOJ supplementation only (time × treatment interaction: P ≤ 0.01). Baseline blood pressure, lipid profile, high-sensitivity C-reactive protein, and endothelin-1 were generally within healthy ranges and unaffected by the intervention.

CONCLUSIONS

A 2-wk consumption of BOJ exerted favorable effects on endothelial function in healthy women and men who were overweight or obese, which is likely mediated by the combined actions of anthocyanin and flavanone metabolites on mechanisms that contribute to enhancing NO bioavailability. This trial was registered at clinicaltrials.gov as NCT03611114.

The association between menstrual symptoms and hypertension among young women: A prospective longitudinal study

OBJECTIVES

To investigate whether menstrual symptoms are associated with increased risk of hypertension among young women, and whether the relationship is bi-directional.

STUDY DESIGN

We included 7729 women participating in the Australian Longitudinal Study on Women's Health, aged 22-27 years in 2000 and who were followed up every 3 years until 2015. Premenstrual syndrome, painful (dysmenorrhoea), heavy (menorrhagia), and irregular menstrual periods over the previous 12 months were self-reported and recorded as 'never', 'rarely', 'sometimes', or 'often'. Questions regarding physician-diagnosed hypertension were asked, specifically for other than during pregnancy (defined as chronic hypertension) and during pregnancy (hypertensive disorder in pregnancy, HDP). Longitudinal data were analysed with generalised estimating equation time-lagged models to estimate relative risks (RRs) and 95 % confidence intervals (CI), adjusted for time-varying covariates.

MIAN OUTCOME MEASURES

Chronic hypertension, HDP, and menstrual disorders.

RESULTS

Over 15 years of follow-up, 757 women (9.8 %) reported having been diagnosed with chronic hypertension. Among 4473 parous women, 483 (10.8 %) reported a diagnosis of HDP. Women who often experienced heavy periods had an increased risk of incident chronic hypertension (RR 1.53, 1.13-2.09), compared with those who had not experienced heavy periods. We also found that women with chronic hypertension had an increased risk of incident heavy (RR 1.23, 1.02-1.50) and irregular periods (RR 1.42, 1.17-1.72). However, there was no apparent association between any menstrual symptoms and subsequent risk of HDP.

CONCLUSIONS

The association between heavy periods (menorrhagia) and chronic hypertension may be bi-directional in young women. Chronic hypertension may also be associated with subsequent risk of irregular periods.

Skeletal muscle microvascular insulin resistance in type 2 diabetes is not improved by eight weeks of regular walking

We aimed to examine whether individuals with type 2 diabetes (T2D) exhibit suppressed leg vascular conductance and skeletal muscle capillary perfusion in response to a hyperinsulinemic-euglycemic clamp and to test whether these two variables are positively correlated. Subsequently, we examined whether T2D-associated skeletal muscle microvascular insulin resistance, as well as overall vascular dysfunction, would be ameliorated by an 8-wk walking intervention (45 min at 60% of heart rate reserve, 5 sessions/week). We report that, relative to healthy subjects, overweight and obese individuals with T2D exhibit depressed insulin-stimulated increases in leg vascular conductance, skeletal muscle capillary perfusion, and Akt phosphorylation. Notably, we found that within individuals with T2D, those with lesser increases in leg vascular conductance in response to insulin exhibited the lowest increases in muscle capillary perfusion, suggesting that limited muscle capillary perfusion may be, in part, linked to the impaired ability of the upstream resistance vessels to dilate in response to insulin. Furthermore, we show that the 8-wk walking intervention, which did not evoke weight loss, was insufficient to ameliorate skeletal muscle microvascular insulin resistance in previously sedentary, overweight/obese subjects with T2D, despite high adherence and tolerance. However, the walking intervention did improve (P < 0.05) popliteal artery flow-mediated dilation (+4.52%) and reduced HbA1c (-0.75%). It is possible that physical activity interventions that are longer in duration, engage large muscle groups with recruitment of the maximum number of muscle fibers, and lead to a robust reduction in metabolic risk factors may be required to overhaul microvascular insulin resistance in T2D.NEW & NOTEWORTHY This report provides evidence that in sedentary subjects with type 2 diabetes diminished insulin-stimulated increases in leg vascular conductance and ensuing blunted capillary perfusion in skeletal muscle are not restorable by increased walking alone. More innovative physical activity interventions that ultimately result in a robust mitigation of metabolic risk factors may be vital for reestablishing skeletal muscle microvascular insulin sensitivity in type 2 diabetes.

Aortic stiffness is associated with changes in retinal arteriole flow pulsatility mediated by local vasodilation in healthy young/middle-age adults

Aortic stiffness is associated with augmented pressure pulsatility in large conduit arteries and remodeling of the microcirculation. However, studies in humans examining the relation between aortic stiffness and end-organ microvascular flow pulsatility are limited. Therefore, we used the retinal microvasculature as an end-organ in vivo model to examine the hypothesis that aortic stiffness would be positively associated with microvascular flow pulsatility index (PI) (flow pulse amplitude/mean flow) in humans. In 40 young/middle-age healthy adults (25-60 yr old, 50% women), aortic stiffness (carotid-femoral pulse wave velocity, CFPWV) and retinal arteriole flow (laser speckle flowgraphy) were examined at rest and during metabolic vasodilation (light flicker). CFPWV and related increases in central pulse pressure (PP) were inversely correlated with arteriole lumen diameter independent of age (CFPWV: R = -0.52, P = 0.001; Central PP: R = -0.39, P = 0.014). Accordingly, microvascular resistance was positively related to CFPWV independent of age (R = 0.35, P = 0.031). Multiple linear regression showed that CFPWV was not a significant determinant of resting arteriole flow PI (β = -0.10, P = 0.64). However, during reduced retinal microvascular resistance using light flicker (P < 0.001), CFPWV was a significant determinant of the percent change in arteriole flow PI (β = 0.58, P = 0.046), but not mean flow (β = -0.17, P = 0.54), where reductions in arteriole flow PI were associated with lower CFPWV. In summary, our findings suggest that higher aortic stiffness and the related increase in central PP in healthy young/middle-age adults are associated with retinal arteriole narrowing and smaller reductions in arteriole flow pulsatility in response to dynamic conditions such as local metabolic vasodilation.NEW & NOTEWORTHY By using the human retinal microvasculature as an end-organ in vivo model, we confirm that aortic stiffness and related increases in central pulse pressure are inversely correlated with retinal arteriole lumen diameter and increased microvascular resistance among heathy young/middle-age adults. Additionally, higher aortic stiffness is not associated with excessive flow pulsatility in the retinal microvasculature under tonic conditions but may be related to limited reductions in retinal arteriole flow pulsatility in response to local vasodilation.