The effect of a 4-week, remotely administered, post-exercise passive leg heating intervention on determinants of endurance performance

PURPOSE

Post-exercise passive heating has been reported to augment adaptations associated with endurance training. The current study evaluated the effect of a 4-week remotely administered, post-exercise passive leg heating protocol, using an electrically heated layering ensemble, on determinants of endurance performance.

METHODS

Thirty recreationally trained participants were randomly allocated to either a post-exercise passive leg heating (PAH, n = 16) or unsupervised training only control group (CON, n = 14). The PAH group wore the passive heating ensemble for 90-120 min/day, completing a total of 20 (16 post-exercise and 4 stand-alone leg heating) sessions across 4 weeks. Whole-body (peak oxygen uptake, gas exchange threshold, gross efficiency and pulmonary oxygen uptake kinetics), single-leg exercise (critical torque and NIRS-derived muscle oxygenation), resting vascular characteristics (flow-mediated dilation) and angiogenic blood measures (nitrate, vascular endothelial growth factor and hypoxia inducible factor 1-α) were recorded to characterize the endurance phenotype. All measures were assessed before (PRE), at 2 weeks (MID) and after (POST) the intervention.

RESULTS

There was no effect of the intervention on test of whole-body endurance capacity, vascular function or blood markers (p > 0.05). However, oxygen kinetics were adversely affected by PAH, denoted by a slowing of the phase II time constant; τ (p = 0.02). Furthermore, critical torque-deoxygenation ratio was improved in CON relative to PAH (p = 0.03).

CONCLUSION

We have demonstrated that PAH had no ergogenic benefit but instead elicited some unfavourable effects on sub-maximal exercise characteristics in recreationally trained individuals.

Association of endothelial function and limb artery indices with coronary artery stenosis severity in patients with hypertension

BACKGROUND

Hypertension is one of the major risk factors for cardiovascular events. This study aims to analyse the association of endothelial function and limb artery indices with coronary artery stenosis (CAS) severity in hypertension based on easily accessible and detailed clinical information, and to help accurately identify high-risk groups and avoid missed diagnosis and misdiagnosis.

METHODS

Admission data of 1,375 consecutive hypertensive patients complicated with suspected coronary atherosclerotic heart disease (CHD) from September 2020 to August 2021 in China-Japan Friendship Hospital were retrospectively assessed. All candidates underwent coronary angiography for screening. A total of 600 eligible patients were classified in the CHD group (n = 359) and non-CHD group (n = 241) based on their coronary angiography results. Subjects in the CHD group were further assigned to 'high stenosis' (n = 178) and 'low stenosis' (n = 181) subgroups based on the median value of Gensini score. Endothelial function and limb artery indicators, including brachial artery flow-mediated vasodilatation (FMD), ankle-brachial index (ABI) and brachial-ankle pulse velocity (baPWV), were examined and compared between subgroups. Multivariate logistic regression analysis and multiple linear regression analysis were carried out to select independent risk factors of CAS severity in hypertension. A predictive equation was conducted according to the results of multivariate logistic regression analysis to make clinical practice easier. As the receiver operating characteristic (ROC) curve had been plotted, the predictive ability of endothelial function and limb artery indicators in CAS severity in hypertension was detected by the area under the curve (AUC).

RESULTS

In patients with hypertension, the FMD (p = 0.023), ABI (p < 0.001) and baPWV (p < 0.001) of CHD patients appeared substantially different from the non-CHD patients. Furthermore, the ABI (p < 0.001) and baPWV (p = 0.032) both independently associated with CAS severity in hypertensive patients with CHD. Based on the results of multivariate logistic regression analysis with CAS severity as a dependent variable, a predictive equation of baPWV, ABI and FMD was developed: combined coefficient = Logit(p)=5.531-0.218*FMD-7.019*ABI + 0.244*baPWV. From the combined coefficients of baPWV, ABI and FMD, the largest AUC was 0.800, suggesting a powerful predictive value of CAS severity in hypertensive patients, followed by ABI (AUC = 0.747, 95%CI 0.693-0.796), baPWV (AUC = 0.704, 95%CI 0.648-0.756) and FMD (AUC = 0.588, 95%CI 0.529-0.645).

CONCLUSION

This study shows that baPWV, ABI and FMD are independent risk factors for CHD, of which, baPWV and ABI are strongly associated with CAS severity in hypertensive patients. The predictive ability of CHD in hypertensive patients may be enhanced through combining the three endothelial function and limb artery indicators. The results may help to facilitate clinical decision-making during treatment and management of coronary artery disease.

Hemoglobin is associated with hypertension-mediated cardiovascular damages in hypertensive patients with high-altitude polycythemia

High-altitude polycythemia (HAPC) is a pathological state resulting from maladaptation to prolonged high-altitude exposure, posing significant risks to the cardiovascular health of highlanders. However, its influence on hypertension-mediated organ damages (HMODs) in hypertensive individuals remains unclear. We recruited hypertensive patients residing at altitudes above 2500 m for over 3 years. A case-control matching was conducted in a 1:1 ratio between hypertensive patients with and without HAPC, based on gender and age. Echocardiography, carotid artery ultrasound, and brachial flow-mediated dilation (FMD) were measured as HMODs. A total of 88 hypertensive patients were included in the analysis, with 44 with HAPC and 44 without HAPC. Patients with HAPC showed significantly higher hemoglobin (HGB) levels (217.82 ± 17.34 vs. 160.16 ± 13.25, P<0.001), a larger left atrium (LA) diameter (35.36 ± 4.25 vs. 33.09 ± 3.55, P = 0.008), and a higher proportion of impaired FMD (95.45% vs. 79.55%, P = 0.049) compared to those without HAPC. No significant differences were found between the two groups in diastolic function parameters, left ventricular mass index (LVMI), relative wall thickness (RWT), or intima-media thickness (IMT). After adjusting for age, gender, and other confounding factors, HGB remained significantly associated with LA diameter (β = 0.034, P = 0.023) and impaired FMD (OR = 1.034, 95% CI 1.001-1.069). After matching for age and gender, hypertensive patients with HAPC exhibited a significantly larger LA diameter and a higher prevalence of impaired FMD compared to those without HAPC. Additionally, HGB was identified as an independent risk factor for both increased LA diameter and impaired FMD in hypertensive patients with HAPC.

Dendritic cell mineralocorticoid receptor controls blood pressure by regulating T helper 17 differentiation: role of the Plcβ1/4-Stat5-NF-κB pathway

BACKGROUND AND AIMS

Dendritic cells (DCs) are closely related to blood pressure (BP) regulation. Mineralocorticoid receptor (MR) is an important drug target for antihypertensive treatment. However, the role of DC MR in the pathogenesis of hypertension has not been fully elucidated. This study aimed to determine the role of DC MR in BP regulation and to explore the mechanism.

METHODS

Renal biopsy and peripheral blood samples were collected from hypertensive patients (HTN) for immunostaining and flow cytometry. Dendritic cell MR knockout (DCMRKO) mice, DC MR overexpressing (DCMROV) mice, DCMROV/IL-17A knockout (DCMROV/IL-17AKO) mice and finerenone-treated C57BL/6 mice were infused with angiotensin II (Ang II) to establish hypertensive models. Western blotting, chromatin immunoprecipitation, co-immunoprecipitation, and in vivo DC depletion or adoptive transfer were used to delineate the functional importance of DC MR in hypertension development.

RESULTS

Mineralocorticoid receptor antagonists (spironolactone and finerenone) suppressed DC aggregation and activation, as well as hypertension in HTN and mice. Compared with littermate control (LC) mice, dendritic cell MR knockout mice had strikingly decreased BPs and attenuated target organ damage after Ang II infusion. Flow cytometry showed that DC MR deficiency mitigated Ang II-induced DC activation and T helper 17 (Th17) cell differentiation. RNA sequencing revealed that MR-deficient DCs had elevated expression of Plcβ1 and Plcβ4, knockdown of which reversed the inhibitory effect of MR deficiency on DC activation and Th17 differentiation. Adoptive transfer of MR-deficient DCs protected Ang II-induced hypertension, whereas knockdown of Plcβ1/4 eliminated the protective effects. At the molecular level, MR negatively regulated Plcβ1/4, which recruited SHP-1 to inactivate of Stat5 activity, resulting in enhanced NF-κB activation and Th17 polarization. Furthermore, DCMROV mice manifested more elevated BPs and target organ damage than control mice after Ang II infusion, and these differences were abolished in DCMROV/IL-17AKO mice. Finally, MR antagonists decreased the aggregation of Th17 in HTN and mice.

CONCLUSIONS

Dendritic cell MR plays important roles in the pathogenesis of hypertension by regulating Th17 through Plcβ1/4-Stat5-NF-κB signalling, and blockade of DC MR is beneficial for treating hypertension.

Induced blood flow oscillations at 0.1 Hz protects oxygenation of severely ischemic tissue in humans

Generating 10-s (∼0.1 Hz) fluctuations or "oscillations" in arterial pressure and blood flow blunts reductions in cerebral tissue oxygenation in response to 15%-20% reductions in cerebral blood flow. To examine the effect of 0.1 Hz hemodynamic oscillations on tissue oxygenation during severe ischemia, we developed a partial limb ischemia protocol targeting a 70%-80% reduction in blood flow. We hypothesized that 0.1 Hz hemodynamic oscillations would attenuate reductions in tissue oxygenation during severe ischemia. Thirteen healthy humans (6 M and 7 F; 27.3 ± 4.2 yr) completed two experimental protocols separated by ≥48 h. In both conditions, an upper arm cuff was used to decrease brachial artery (BA) blood velocity by ∼70%-80% from baseline. In the oscillation condition (0.1 Hz), 0.1 Hz hemodynamic oscillations were induced by intermittently inflating and deflating bilateral thigh cuffs every 5 s during forearm ischemia. In the control condition (0 Hz), the thigh cuffs were inactive. BA blood flow, forearm tissue oxygenation (SmO2), and arterial pressure were measured continuously. The initial reduction in BA blood velocity was tightly matched between protocols (0 Hz: -76.9 ± 7.9% vs. 0.1 Hz: -75.5 ± 7.4%, P = 0.49). Although 0.1 Hz oscillations during forearm ischemia had no effect on the reduction in BA velocity (0 Hz: -73.0 ± 9.9% vs. 0.1 Hz: -73.3 ± 8.2%, P = 0.91), the reduction in SmO2 was attenuated (0 Hz: -35.7 ± 8.6% vs. 0.1 Hz: -27.2 ± 8.9%, P = 0.01). These data provide further evidence for the use of 0.1 Hz hemodynamic oscillations as a potential therapeutic intervention for conditions associated with severe tissue ischemia (e.g., hemorrhage and stroke).NEW & NOTEWORTHY We investigated the effects of induced 10-s (0.1 Hz) oscillations in blood flow on forearm tissue oxygenation during severe ischemia. Intermittent inflation of bilateral thigh cuffs was used as a clinically applicable method to drive blood flow oscillations. In support of our hypothesis, 0.1 Hz oscillations in blood flow blunted reductions in forearm tissue oxygenation. These results further support the potential use of oscillatory hemodynamics as a therapeutic intervention for ischemic conditions.

Impact of moderate-intensity aerobic exercise in combined hypoxic and hot conditions on endothelial function

There is no study that has investigated the impact of exercise in a combined hypoxic and hot environment on endothelial function. Therefore, we tested whether aerobic exercise in a combined hypoxic and hot conditions induces further enhancement of endothelial function. Twelve healthy males cycled at a constant workload (50% of their maximal oxygen uptake under normoxic/thermoneutral conditions) for 30 min in four different environments: exercise under normoxic condition (NOR: fraction of inspiratory oxygen or FiO2 = 20.9%, 20°C), exercise under hypoxic condition (HYP: FiO2 = 14.5%, 20°C), exercise under hot condition (HOT: FiO2 = 20.9%, 30°C), and exercise under combined hypoxia and hot conditions (HH: FiO2 = 14.5%, 30°C). Before, during, and after exercise, cardiovascular variables (e.g., heart rate, blood flow, and shear rate), blood variables, and endothelial function evaluated by flow-mediated dilation (FMD) were assessed. Heart rates were significantly higher throughout the HH trial's experimental period than the other trials (p < 0.05). However, in the HH trial, brachial artery blood flow and shear rate did not differ from those in other trials after exercise. Plasma catecholamines (epinephrine, norepinephrine, and dopamine) elevations in response to exercise were significantly higher in the HH trial than in the other three trials (p < 0.05). No considerable differences were observed in FMD responses among trials before and after the exercise. In conclusion, aerobic exercise in a combined hot and hypoxic environment further activated sympathetic nervous activity but did not considerably enhance blood flow, shear rate, or endothelial function.

The relationship between endothelial-dependent flow-mediated dilation and diastolic function in type 2 diabetes

AIMS

Diastolic dysfunction represents the earliest and most common manifestation of diabetic cardiomyopathy. Nitric oxide (NO), a potent vasodilator and anti-inflammatory mediator released from the subendocardial and coronary endothelium, favors left ventricular distensibility and relaxation. In type 2 diabetes (T2D), the NO bioavailability is reduced due to the oxidative stress and inflammatory state of the endothelium, because of chronic hyperglycemia. The aim of the present research is to evaluate the relationship between endothelial function and diastolic function in subjects with T2D.

METHOD

Subjects with T2D and age and sex-matched healthy controls were consecutively recruited. All participants underwent flow-mediated dilation (FMD) to assess endothelial function, and echocardiography to evaluate diastolic function.

RESULTS

Thirty-five patients (6 women, 29 men) and 35 healthy controls were included in the final analysis. FMD was significantly lower in T2D than controls (4.4 ± 3.4 vs. 8.5 ± 4.3%, p = 0.001). T2D presented different abnormalities in diastolic function compared to controls: lower E/A (early to late diastolic transmitral flow velocity), lower septal and lateral e' (early diastolic myocardial tissue velocity at septum and lateral wall), and higher E/e' (surrogate of filling pressure). In subjects with T2D, we observed a significant correlation between FMD and E/e' (r = -0.63, p = 0.001), lateral e' (r = 0.44, p = 0.03), and septal e' (r = 0.39, p = 0.05).

CONCLUSIONS

Our observational study demonstrated a link between FMD and diastolic dysfunction in subjects with type 2 diabetes.

Variability of flow-mediated dilation across lower and upper limb conduit arteries

Endothelial dysfunction is an early predictor of atherosclerosis and cardiovascular disease. Flow-mediated dilation (FMD) is the gold standard to assess endothelial function in humans. FMD reproducibility has been mainly assessed in the brachial artery (BA) with limited research in lower limb arteries. The purpose of this study was to compare FMD reproducibility in the upper limb BA and lower limb superficial femoral artery (SFA) in young healthy adults.Fifteen young healthy adults (nine males; six females) underwent FMD, resting diameter, velocity, and shear rate measurements on three occasions to determine intra-and inter-day reproducibility in both BA and SFA, assessed by coefficient of variation (CV), intraclass correlation coefficient (ICC), and Bland-Altman plots.BA FMD CVs (intra-day: 4.2%; inter-day: 8.7%) and ICCs (intra-day: 0.967; inter-day: 0.903) indicated excellent reproducibility and reliability, while for SFA FMD, both CVs (intra-day: 11.6%; inter-day: 26.7%) and ICCs (intra-day: 0.898; inter-day: 0.651) showed good/moderate reproducibility and reliability. BA FMD was significantly more reproducible than SFA FMD (p < 0.05). Diameter reproducibility was excellent and similar between arteries, while resting velocity and shear rate have lower reproducibility in the BA compared to SFA. Bland-Altman plots displayed no proportional and fixed bias between measurements.In summary, SFA FMD is less reproducible than BA FMD, with identical volume of ultrasound training. Given the increasing interest in using SFA FMD to test the efficacy of interventions targeting lower limb's vascular health and as a potential biomarker for peripheral arterial disease risk, future studies should ensure higher levels of training for adequate reproducibility.

Characterizing vascular and hormonal changes in women across the life span: a cross-sectional analysis

Vascular dysfunction, marked by lower endothelial function and increased aortic stiffness, is a nontraditional risk factor that precedes the development of cardiovascular disease (CVD). However, the age at which these changes in vascular function occur in women and the degree to which reproductive hormones mediate these changes has not been characterized. Women free from major disease were enrolled across the adult life span (aged 18-70 yr, n = 140). Endothelial function was assessed as flow-mediated dilation (FMD) of the brachial artery during reactive hyperemia using duplex ultrasound and expressed as percent dilation. Aortic stiffness was measured by carotid-femoral pulse wave velocity (cfPWV). Blood samples were obtained to quantify reproductive hormone concentration. Regression models determined age-related breakpoints and mediating factors between age and vascular outcomes. FMD declined with age with a breakpoint and steeper decline occurring at 47 yr of age. Thereafter, age was independently associated with lower FMD (B = -0.13, P < 0.001). cfPWV was relatively stable until a breakpoint at age 48, and age was independently associated with higher cfPWV thereafter (B = 0.10, P < 0.001). Path analysis revealed that the association between age and FMD was partially mediated by follicle-stimulating hormone (abind = 0.051, P = 0.01) and progesterone (abind = 0.513, P < 0.001) but not estradiol (abind = -0.004, P = 0.08). No mediation was present for cfPWV. Age was associated with endothelial dysfunction and aortic stiffness in women beginning at 47 and 48 yr old, respectively, 3 to 4 yr before the average age of menopause. The association between age and endothelial dysfunction was explained in part by elevations in follicle-stimulating hormone and progesterone, but not declining estradiol.NEW & NOTEWORTHY We demonstrate that the age at which endothelial function declines and aortic stiffness increases in healthy women is 47 and 48, respectively. The inflection point in flow-mediated dilation (FMD) is 6 yr earlier than previously reported, and the association between age and FMD was mediated by follicle-stimulating hormone (FSH) and progesterone (P4) but not estradiol (E2).

TG Vascutrack: A User-Friendly and Open-Source Software for Automated Extraction of Arterial Diameter and Velocity Profile Data From Vascular Ultrasound Videos

Existing automated software for vascular ultrasound data extraction lacks free, open-source options suitable for professionals without coding experience. These programs typically include signal-cleaning algorithms, resulting in processed output without access to raw data. To address these needs, we developed TG Vascutrack, an open-source and user-friendly software tailored for non-coder professionals. It features a graphical interface, multiple functionalities, and provides access to raw data. Comparative analysis against validated software and manual extraction revealed minimal biases and standard deviations in diameter and velocity measurements. TG Vascutrack offers a free, promising solution for non-coders needing automated vascular ultrasound data extraction.

The acute effects of dietary nitrate supplementation on postmenopausal endothelial resistance to ischemia reperfusion injury: a randomized, placebo-controlled, double blind, crossover clinical trial

Postmenopausal cardiovascular health is a critical determinant of longevity. Consumption of beetroot juice (BR) and other nitrate-rich foods is a safe, effective non-pharmaceutical intervention to increase systemic bioavailability of the vasoprotective molecule, nitric oxide, through the exogenous nitrate (NO3 -)-nitrite (NO2 -)-nitric oxide (NO) pathway. We hypothesized that a single dose of nitrate-rich beetroot juice (BRnitrate 600 mg NO3 -/140 mL, BRplacebo ∼ 0 mg/140 mL) would improve resting endothelial function and resistance to ischemia-reperfusion (IR) injury to a greater extent in early-postmenopausal (1-6 years following their final menstrual period (FMP), n = 12) compared to late-postmenopausal (6+ years after FMP, n = 12) women. Analyses with general linear models revealed a significant (p < 0.05) time*treatment interaction effect for brachial artery adjusted flow-mediated dilation (FMD). Pairwise comparisons revealed that adjusted FMD was significantly lower following IR-injury in comparison to all other time points with BRplacebo (early FMD 2.51 ± 1.18%, late FMD 1.30 ± 1.10, p < 0.001) and was lower than post-IR with BRnitrate (early FMD 3.84 ± 1.21%, late FMD 3.21 ± 1.13%, p = 0.014). A single dose of BRnitrate significantly increased resting macrovascular function in the late postmenopausal group only (p = 0.005). Considering the postmenopausal stage-dependent variations in endothelial responsiveness to dietary nitrate, we predict differing mechanisms underpin macrovascular protection against IR injury.

Vascular function in multiple sclerosis: Systematic review with meta-analysis

BACKGROUND

Vascular comorbidities are prevalent in persons with multiple sclerosis (MS), yet less is known about underlying vascular function (VF). We performed a systematic review with meta-analysis of studies that compared VF in persons with MS and healthy controls and examined factors that may moderate the difference in vascular outcomes between groups.

METHODS

We conducted a systematic search using PubMed/MEDLINE, CINAHL, and Embase from inception through March 2024. The search identified studies that included comparisons of VF between MS and controls on a range of function and structure outcomes (e.g., pulse wave velocity, augmentation index, arterial diameter, intima-media thickness, flow-mediated dilation). Effect sizes were calculated as standardized mean differences (SMD) using Hedge's g with a positive effect indicating worse VF in MS than controls. The meta-analysis involved a multilevel random effects model with follow-up moderator analyses.

RESULTS

Fourteen studies met the inclusion criteria and yielded 49 effect sizes for meta-analysis. The MS subjects (N = 614) were predominantly female (72.0 %), with mean ages ranging from 29.9 to 54.4 years. There was a moderate difference in VF between persons with MS and healthy controls (SMD [95 % CI] = 0.56 [0.08, 1.03]; p = 0.02), and the effects were heterogenous (Q48=634.5, p < 0.01; I2=94.39 %). There was a greater difference in arterial stiffness between MS and controls (0.78 [0.21, 1.36], p = 0.008), but not in other arterial structure or function outcomes (p > 0.05). No significant moderators were detected (p > 0.05).

CONCLUSIONS

The cumulative evidence supports that persons with MS have worse VF, notably greater arterial stiffness, than healthy controls. Such findings support future research on the cause, consequences, and management of arterial stiffness among persons with MS.

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.

A Study of the Relationship Between Objective Tests to Diagnose Erectile Dysfunction and Markers of Cardiovascular Disease

Background: Erectile dysfunction (ED) can stem from various organic and functional causes but is often linked to vascular health and cardiovascular disease. Limited data exist on how cardiovascular disease markers correlate with objective ED tests like the Nocturnal Penile Tumescence and Rigidity (NPTR) test and Penile Color Doppler Ultrasound (PCDU). Methods: A prospective observational study was performed, and 58 men with ED were assessed using the International Index of Erectile Function-15 (IIEF-15), NPTR test, and PCDU. Peripheral vascular health was evaluated through carotid intima-media thickness (cIMT) and brachial flow-mediated dilation (FMD). Results: Out of the participants, 44 had normal NPTR results, while 14 had abnormal results. The group with abnormal NPTR results was significantly older and had higher rates of hypertension and diabetes. Although the IIEF-15 scores were similar between the two groups, those with abnormal NPTR results had a lower peak systolic velocity (PSV) and a higher prevalence of impaired PSV. Correlations between the IIEF, NPTR, PCDU, and peripheral vascular markers lost significance after the age adjustment. Conclusions: This study suggests that abnormal NPTR results, combined with cardiovascular risk factors, may signal vascular ED and generalized vasculopathy, highlighting the need for cardiovascular assessment. An accurate ED diagnosis should integrate clinical evaluation with multiple tests while considering aging as a key risk factor.

VascuFit: Aerobic exercise improves endothelial function independent of cardiovascular risk: A randomized-controlled trial

BACKGROUND AND AIMS

Endothelial dysfunction predicts elevated cardiovascular (CV) risk in healthy individuals. Aerobic exercise reduces endothelial dysfunction in part by improving CV risk factors. Yet, this explains less than 50 % of the effect and a direct influence of exercise training on the endothelium is discussed as possible contributor. The VascuFit study applied non-linear periodized aerobic exercise (NLPE) training to assess its multilevel effects on endothelial function including potential epigenetic endothelial modifications by circulating micro-ribonucleic acids (endomiRs).

METHODS

Sedentary adults with elevated CV risk between 40 and 60 years were randomized 2:1 and engaged in an eight-week ergometer-based NLPE training (n = 30) or received standard exercise recommendations (n = 14). Macro-, microvascular, cellular and molecular adaptations were assessed via brachial-arterial flow-mediated dilation (baFMD), static retinal vessel analysis (SVA), flow cytometry, and endomiRs regulating key pathways of endothelial function. Statistics included ANCOVA, Principal Component Analysis (PCA), and regression analyses.

RESULTS

baFMD improved by 2.38 % (CI:0.70-4.06, p = 0.007) independent of CV risk, whereas SVA parameters and circulating endothelial (progenitor) cells did not significantly change in the NLPE group. The mean distance between baseline and follow-up PCA loadings of the endomiR dataset explaining 44.2 % of dataset variability was higher in the NLPE-group compared to the control group (2.71 ± 2.02 vs. 1.65 ± 0.93). However, regression analyses showed no evidence of endomiRs explaining the improvement of baFMD.

CONCLUSIONS

The improvement of macrovascular endothelial function by aerobic exercise training was independent from CV risk factors. Increased heterogeneity among endomiRs did not explain this effect, but suggests an adaptive response to the exercise stimulus on the epigenetic level.

Potential preservative mechanisms of cardiac rehabilitation pathways on endothelial function in coronary heart disease

Cardiac rehabilitation, a comprehensive exercise-based lifestyle and medical management, is effective in decreasing morbidity and improving life quality in patients with coronary heart disease. Endothelial function, an irreplaceable indicator in coronary heart disease progression, is measured by various methods in traditional cardiac rehabilitation pathways, including medicinal treatment, aerobic training, and smoking cessation. Nevertheless, studies on the effect of some emerging cardiac rehabilitation programs on endothelial function are limited. This article briefly reviewed the endothelium-beneficial effects of different cardiac rehabilitation pathways, including exercise training, lifestyle modification and psychological intervention in patients with coronary heart disease, and related experimental models, and summarized both uncovered and potential cellular and molecular mechanisms of the beneficial roles of various cardiac rehabilitation pathways on endothelial function. In exercise training and some lifestyle interventions, the enhanced bioavailability of nitric oxide, increased circulating endothelial progenitor cells (EPCs), and decreased oxidative stress are major contributors to preventing endothelial dysfunction in coronary heart disease. Moreover, the preservation of endothelial-dependent hyperpolarizing factors and inflammatory suppression play roles. On the one hand, to develop more endothelium-protective rehabilitation methods in coronary heart disease, adequately designed and sized randomized multicenter clinical trials should be advanced using standardized cardiac rehabilitation programs and existing assessment methods. On the other hand, additional studies using suitable experimental models are warranted to elucidate the relationship between some new interventions and endothelial protection in both macro- and microvasculature.

The Cardiometabolic Risk in Women with Polycystic Ovarian Syndrome (PCOS): From Pathophysiology to Diagnosis and Treatment

Polycystic Ovarian Syndrome (PCOS) is a prevalent endocrine disorder affecting women of reproductive age, with significant variations in presentation characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovarian morphology. Beyond reproductive health, it may also pose crucial long-term cardiometabolic risks, especially for women with specific types of PCOS, contributing to early subclinical cardiovascular atherosclerotic alterations such as endothelial dysfunction, increased arterial stiffness, and coronary artery calcium levels, respectively. Moreover, the precise relationship between clinical cardiovascular disease (CVD) and PCOS remains debated, with studies demonstrating an elevated risk while others report no significant association. This review investigates the pathophysiology of PCOS, focusing on insulin resistance and its link to subclinical and clinical cardiovascular disease. Diagnostic challenges and novel management strategies, including lifestyle interventions, medications like metformin and glucagon-like peptide-1 receptor agonists (GLP-1RAs), hormonal contraceptives, and bariatric surgery, are further discussed. Recognizing the cardiometabolic risks associated with PCOS, a comprehensive approach and early intervention should address both the reproductive and cardiometabolic dimensions of the syndrome.

The impact of uninterrupted sitting on central and peripheral cardiovascular function in pre-menopausal and post-menopausal women

Independently, both prolonged uninterrupted sitting and the onset of menopause negatively impact markers of cardiovascular risk. Whether their combination augment these responses additively remains unknown. This study assessed whether prolonged uninterrupted sitting causes greater central and peripheral cardiovascular dysfunction in post-menopausal women compared to pre-menopausal women. To address this, 23 healthy women (13 pre-menopausal [43.77 ± 4.30 years] and 10 post-menopausal [57.20 ± 8.55 years]) sat uninterrupted for 2-h. Carotid-femoral pulse wave velocity (cf-PWV), pulse wave analysis (PWA), lower limb venous pooling (HHb), and calf circumference were assessed pre-and post-sitting using general linear mixed models, with age as a covariate. Changes in MAP over time (both between and within groups) was assessed using a two-way repeated-measures-ANOVA. There were no significant interactions for any outcome measures. However, for cf-PWV, there was a significant main effect of group (Δ = 0.854 ± 0.354 m s-1; p = 0.026, ηp2 = 0.707). For PWA, only heart rate (HR) and pressure forwards (Pf) showed significant main effects 13 of time [Δ = 6 ± 1 bts-min-1, p < 0.001, ηp2 = 0.861] and group [Δ = 3.893 ± 1.450 mmHg, p = 0.016, ηp2 = 0.271], respectively. Both HHb (Δ = 2.737 ± 0.952, p = 0.009, ηp2 = 0.742) and calf circumference (Δ = 0.812 ± 0.128 cm, p < 0.001, ηp2 = 0.863) significantly increased over time. Whilst post-menopausal women demonstrated greater overall arterial stiffness (increased cf-PWV at baseline), there was no difference in cardiovascular response (central or peripheral) to 2-h of prolonged sitting between the pre- and post-menopausal women.

Menstrual and oral contraceptive pill cycles minimally influence vascular function and associated cellular regulation in premenopausal females

Historical exclusion of females in research has been, in part, due to the perceived influence of natural menstrual (NAT) and oral contraceptive pill (OCP) cycles on vascular outcomes. NAT and OCP cycle phases may influence brachial artery (BA) endothelial function, however, findings are mixed. Minimal research has examined arterial stiffness, smooth muscle, and lower limb endothelial function. The purpose of this study was to investigate the influence of NAT and OCP cycles on cardiovascular outcomes and cellular regulation. Forty-nine premenopausal females (n = 17 NAT, n = 17 second generation OCP, n = 15 third generation OCP) participated in two randomized order visits in the low (LH, early follicular/placebo) and high (HH, midluteal/active) hormone cycle phases. BA and superficial femoral artery (SFA) endothelial function [flow-mediated dilation (FMD) test], smooth muscle function (nitroglycerine-mediated dilation test), and carotid and peripheral (pulse wave velocity) arterial stiffness were assessed. Cultured female human endothelial cells were exposed to participant serum for 24 h to examine endothelial nitric oxide synthase (eNOS) and estrogen receptor-α (ERα) protein content. BA FMD was elevated in the HH vs. LH phase, regardless of group (HH, 7.7 ± 3.5%; LH, 7.0 ± 3.3%; P = 0.02); however, allometric scaling for baseline diameter resulted in no phase effect (HH, 7.6 ± 2.6%; LH, 7.1 ± 2.6%; P = 0.052, d = 0.35). SFA FMD, BA, and SFA smooth muscle function, arterial stiffness, and eNOS and ERα protein content were unaffected. NAT and OCP phases examined have minimal influence on vascular outcomes and ERα-eNOS pathway, apart from a small effect on BA endothelial function partially explained by differences in baseline artery diameter. NEW & NOTEWORTHY Comprehensive evaluation of the cardiovascular system in naturally cycling and second and third generation OCP users indicates no major influence of hormonal phases examined on endothelial function and smooth muscle function in the arteries of the upper and lower limbs, arterial stiffness, or underlying cellular mechanisms. Study findings challenge the historical exclusion of female participants due to potentially confounding hormonal cycles; researchers are encouraged to consider the hormonal environment in future study design.

Evaluating the impact of short-term nitrate-rich dietary supplementation on endothelial function in COPD: A randomized crossover study

AIM

This study aimed to investigate the acute effects of dietary nitrate ingestion through l-arginine supplementation or dehydrated beet consumption on endothelial function in chronic obstructive pulmonary disease (COPD) patients. The secondary outcome was to analyze arterial stiffness, plasma nitrate, and nitrate/protein concentration.

METHODS

In this randomized crossover study, subjects with COPD underwent three series of supplementation: (1) l-arginine, (2) dehydrated beetroot, and (3) a placebo that appeared like the other supplements. Each intervention lasted 14 days, with a 7-day washout period between series. Participants underwent endothelial function assessment using flow-mediated dilatation (FMD), and plasma nitrate levels were measured at the end of each supplementation series.

RESULTS

Seventeen subjects (twelve male) completed the study protocol. Only five subjects presented endothelial dysfunction (RHI ≤0.51) at baseline. The mean baseline characteristics included age 66.5 ± 9.4 years, BMI 27.5 ± 4.5 kg/m2, FEV1, 0.79 (0.67-1.06) L. There were no differences (p > 0.05) between the groups or from pre-to post-interventions for RHI and arterial stiffness index (AIx) values, as well as parameters of endothelium-dependent vasodilation, such as blood flow velocity (BFV), shear stress, shear rate, FMD (mm), and FMD%. There was also no differences (p > 0.05) between the groups or from pre-to post-interventions plasma nitrate levels.

CONCLUSIONS

Acute dietary supplementation with nitrates, at the doses provided, did not show a significant improvement in endothelial function assessed by FMD, EndoPAT, or plasma nitrate levels in COPD. These findings suggest that a higher dose or prolonged supplementation might be required to achieve a therapeutic effect.

Berberine ameliorates vascular dysfunction by downregulating TMAO-endoplasmic reticulum stress pathway via gut microbiota in hypertension

The gut microbial metabolite trimethylamine N-oxide (TMAO) is regarded as a novel risk factor for hypertension. Berberine (BBR) exerts cardiovascular protective effects by regulating the gut microbiota-metabolite production pathway. However, whether and how BBR alleviates TMAO-induced vascular dysfunction in hypertension remains unclear. In the present study, we observed that plasma TMAO and related bacterial abundance were significantly elevated and negatively correlated with vascular function in 86 hypertensive patients compared with 46 normotensive controls. TMAO activated endoplasmic reticulum stress (ERS) signaling pathway to promote endothelial cell dysfunction and apoptosis in vitro. BBR (100, 200 mg · kg-1 ·d-1) for 4 weeks ameliorates TMAO-induced vascular dysfunction and ERS activation in a choline-angiotensin II hypertensive mouse model. We found that plasma TMAO levels in 15 hypertensive patients treated with BBR (0.4 g, tid) were reduced by 8.8 % and 16.7 % at months 1 and 3, respectively, compared with pretreatment baseline. The oral BBR treatment also improved vascular function and lowered blood pressure. Faecal 16 S rDNA showed that BBR altered the gut bacterial composition and reduced the abundance of CutC/D bacteria in hypertensive mice and patients. In vitro bacterial cultures and enzyme reaction systems indicated that BBR inhibited the biosynthesis of TMAO precursor in the gut microbiota by binding to and inhibiting the activity of CutC/D enzyme. Our results indicate that BBR improve vascular dysfunction at least partially by decreasing TMAO via regulation of the gut microbiota in hypertension.

Micro- and macrovascular function in the highest city in the world: a cross sectional study

Background

Since vascular responses to hypoxia in both healthy high-altitude natives and chronic mountain sickness (a maladaptive high-altitude pathology characterised by excessive erythrocytosis and the presence of symptoms-CMS) remain unclear, the role of inflammation and oxidative/nitrosative stress on the endothelium-dependent and -independent responses in both the micro- and macrocirculation, in healthy Andeans at different altitudes and in CMS patients, was examined.

Methods

94 men were included: 18 lowlanders (LL), 38 healthy highlanders permanently living at 3800 m (n = 21-HL-3800) or in La Rinconada, the highest city in the world (5100-5300 m) (n = 17-HL-5100/No CMS). Moreover, 14 participants with mild (Mild CMS) and 24 with moderate to severe CMS (Mod/Sev CMS) were recruited. All undertook two reactivity tests: i) local thermal hyperaemia (microcirculation) and ii) flow-mediated dilation (macrocirculation). Endothelium-independent function (glyceryl trinitrate) was also assessed only in La Rinconada.

Findings

Conductance and skin blood flow velocity during the microcirculation test, as well as macrocirculation progressively decreased with altitude (LL > HL-3800 > HL-5100/No CMS). CMS also induced a decrease in macrocirculation (HL-5100/No CMS > Mild CMS = Mod/Sev CMS), while glyceryl trinitrate restored vascular function. Both oxidative stress and nitric oxide metabolites increased with altitude only. Principal component analysis revealed that increasing inflammation with altitude was associated with a progressive decline in both micro- and macrovascular function in healthy highlanders.

Interpretation

Both micro and macrovascular function are affected by chronic exposure to hypoxia, the latter being further compounded by CMS.

Funding

The "Fonds de dotation AGIR pour les maladies chroniques", the "Air Liquide Foundation", and the "French National Research Agency".

Acute impact of inorganic nitrate supplementation after ischemia and during small muscle mass exercise in postmenopausal females: A pilot study

Menopause is associated with reduced endothelial-dependent vasodilation and increased cardiovascular disease (CVD) risk. Dietary nitrate, a non-pharmacological approach, may increase vasodilatory capacity consequentially reducing CVD risk. We investigated macro- and microvascular function after acute nitrate supplementation in postmenopausal females (PMF). Vascular function was studied with flow-mediated vasodilation (FMD) and near-infrared post occlusive reactive hyperemia (PORH). Incremental handgrip exercise was performed to investigate blood flow and tissue oxygenation. We hypothesized acute dietary nitrate would not impact resting endothelial measures but would increase post ischemic vasodilation and incremental exercise blood flow. Late-phase PMF (n = 12) participated in a randomized crossover design with 140 mL of nitrate-rich (NR) beetroot juice or nitrate-poor black currant juice. Testing included a 5-min FMD, a 3-min ischemic exercise FMD, and incremental exercise at 10%, 15%, and 20% maximal voluntary contraction to measure blood flow and pressure responses. A p ≤ 0.05 was considered significant. One-way ANOVA indicated lower resting pressures, but no change to FMD, or PORH in either protocol. Two-way repeated measures ANOVA indicated NR supplementation significantly reduced mean arterial pressure at rest and during incremental exercise at all intensities without changes to blood flow. Acute nitrate is effective for resting and exercising blood pressure management in PMF.

Assessing the effect of anthocyanins through diet and supplementation on cognitive function in older adults at risk for dementia: protocol for a randomised controlled trial

INTRODUCTION

Promising evidence is emerging for the procognitive, anti-inflammatory and neuroprotective properties of dietary flavonoids, particularly anthocyanins that provide red, purple and blue plant pigments.

METHODS AND ANALYSIS

The 'Food for Thought' study is a multicentre, 6-month randomised, parallel 3-arm clinical trial. Its primary aim is to investigate whether anthocyanin consumption, either through diet or supplementation, can prevent memory loss progression and improve inflammatory and cardiovascular health in older adults at risk for dementia. Eligible participants will include those aged 60-85 years with a diagnosis of amnestic mild cognitive impairment or with a self-referral of memory concerns and scoring ≤13 on the Memory Index Score within the Telephone Montreal Cognitive Assessment screening test. Participants will be randomised to one of three arms: High anthocyanin ('purple foods') diet (aiming for a target of 250 mg anthocyanins/day); freeze-dried product derived from blackcurrants (250 mg anthocyanins/day); or control (coloured maltose powder). The primary outcome is auditory anterograde memory functioning assessed by the Buschke and Grober Free and Cued Selective Reminding Test-Immediate Recall. Secondary outcomes are additional cognitive functions including processing speed, working memory, aspects of executive functioning (attentional shifting and word generativity) and premorbid estimate as well as subjective memory problems and self-reported depression symptoms. Additional secondary outcomes are blood pressure, inflammatory biomarkers, brain-derived neurotrophic factor, fatty acid profile, apolipoprotein E and polyphenol metabolites, gut microbiota composition and function and vascular and microvascular endothelial function tests. Repeated measures analysis of variance and/or mixed linear modelling will evaluate changes over time, with the inclusion of covariates.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the Greater Western Human Research Ethics Committee (2021/ETH12083). A Consumer Advisory Group was established to guide and review the protocol and dissemination strategy. The results of this trial are intended to be published in a peer-reviewed journal.

TRIAL SPONSOR

National Health and Medical Research Centre Dementia Collaborative Research Centre.Start date of clinical trial: 02 September 2022.Expected end date: 11 October 2024.

TRIAL REGISTRATION NUMBER

ACTRN12622000065796.

Identifying the Role of Flow-Mediated Dilatation Assessment in Acute Coronary Syndromes: A Systematic Review

In the context of the global burden of cardiovascular disease, the development of novel, patient-targeted diagnostic and therapeutic strategies is of paramount importance. Acute coronary syndromes (ACS) comprise a subset of cardiovascular disease, with constantly increasing prevalence requiring urgent attention. Flow-mediated dilatation (FMD), a noninvasive method for the evaluation of endothelial function, has been previously implemented in patients with ACS. A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted in order to identify all relevant studies assessing the implementation of FMD among patients with ACS. Our review reflects an effort to present all available data regarding the role of FMD to date, a valuable noninvasive and easy accessible diagnostic tool, in the prognosis of patients with ACS. FMD evaluation in patients with ACS reveals a decline in values, indicative of the presence of endothelial function among this distinct patient group. FMD has also been used to assess the response to various treatments, as well as to predict major adverse cardiovascular events. Dynamic responses to interventions highlights its potential in the evolving field of interventional cardiology.

Comparative effects of sacubitril/valsartan and ACEI/ARB on endothelial function and arterial stiffness in patients with heart failure: a protocol for systematic review and meta-analysis

INTRODUCTION

Heart failure (HF) is a complex syndrome that affects millions of people worldwide and leads to significant morbidity and mortality. Sacubitril/valsartan, a combination drug consisting of a neprilysin inhibitor and an angiotensin receptor blocker (ARB), has shown a greater improvement in the prognosis of HF than ACE inhibitors (ACEI) or ARB. Recent studies have found that ACEI/ARB or sacubitril/valsartan can increase flow-mediated dilation (FMD) and reduce pulse wave velocity (PWV), which are independent predictors of cardiovascular events and HF prognosis. The purpose of this study is to assess and compare the effect of sacubitril/valsartan and ACEI/ARB on FMD and PWV using meta-analysis and further provide a reference for the role of sacubitril/valsartan in the treatment of HF.

METHODS AND ANALYSIS

Clinical randomised controlled trials investigating the effect of sacubitril/valsartan and/or ACEI/ARB on FMD and PWV in patients with HF will be searched in the relevant database, including PubMed, Web of Science, Embase, Cochrane Library and China's National Knowledge Infrastructure up to January 2024. The outcomes of interest are changes in endothelial function assessed by FMD and changes in arterial stiffness assessed by PWV. The risk of bias was evaluated using the revised Cochrane risk of bias tool for randomised trials (RoB2.0). Review Manager V.5.3 software is used for meta-analysis data synthesis, sensitivity analysis, meta-regression analysis, subgroup analysis and risk of bias assessment. The reporting bias of studies will be evaluated using the funnel plot, in which symmetry will be assessed by Begg's and Egger's tests. The evidence quality of the included studies will be evaluated by the Grading of Recommendations Assessment, Development, and Evaluation.

ETHICS AND DISSEMINATION

This study only analyses research data from the published literature and therefore does not require ethical approval. We will submit the systematic review to a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42024538148.

Association between endothelial function and skin advanced glycation end-products (AGEs) accumulation in a sample of predominantly young and healthy adults

BACKGROUND

In populations with chronic disease, skin autofluorescence (SAF), a measure of long-term fluorescent advanced glycation end-products (AGEs) accumulation in body tissues, has been associated with vascular endothelial function, measured using flow-mediated dilation (FMD). The primary aim of this study was to quantify the relationship between endothelial function and tissue accumulation of AGEs in adults from the general population to determine whether SAF could be used as a marker to predict early impairment of the endothelium.

METHODS

A cross-sectional study was conducted with 125 participants (median age: 28.5 y, IQR: 24.4-36.0; 54% women). Endothelial function was measured by fasting FMD. Skin AGEs were measured as SAF using an AGE Reader. Participant anthropometry, blood pressure, and blood biomarkers were also measured. Associations were evaluated using multivariable regression analysis and were adjusted for significant covariates.

RESULTS

FMD was inversely correlated with SAF (ρ = -0.50, P < 0.001) and chronological age (ρ = -0.51, P < 0.001). In the multivariable analysis, SAF, chronological age, and male sex were independently associated with reduced FMD (B [95% CI]; -2.60 [-4.40, -0.80]; -0.10 [-0.16, -0.03]; 1.40 [0.14, 2.67], respectively), with the multivariable model adjusted R2 = 0.31, P < 0.001.

CONCLUSIONS

Higher skin AGE levels, as measured by SAF, were associated with lower FMD values, in a predominantly young, healthy population. Additionally, older age and male participants exhibited significantly lower FMD values, corresponding with compromised endothelial function. These results suggest that SAF, a simple and inexpensive marker, could be used to predict endothelial impairment before the emergence of any structural artery pathophysiology or classic cardiovascular disease risk markers.

TRIAL REGISTRATION

The study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12621000821897) and concurrently entered into the WHO International Clinical Trials Registry Platform under the same ID number.

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.

Acute Effects of Breaking up Sitting Time With Isometric Wall Squat Exercise on Vascular Function and Blood Pressure in Sedentary Adults: Randomized Crossover Trial

PURPOSE

The World Health Organization has recommended breaking up sitting time to improve cardiovascular health. However, whether isometric exercise can be effectively used as a strategy to break up sitting time remains unclear. Thus, the aim of this study was to analyze the acute effects of breaking up prolonged sitting with isometric wall squat exercise (IWSE) on vascular function and blood pressure (BP) in sedentary adults.

METHODS

This randomized crossover trial included 17 adults (53% male, 26 ± 6 yr, 22.4 ± 3.6 kg/m 2 ) with high sedentary behavior (≥ 6 hr/d). The participants completed 2 experimental sessions in a randomized order, both sharing a common sitting period of 180 min: Breaks (2-min breaks were incorporated into the IWSE, with participants maintaining their knees at the angle determined by the incremental test, which occurred every 30 min) and Control (sitting for 180 min continuously). Popliteal artery flow-mediated dilation (FMD) and brachial BP were measured before and at 10 and 30 min after the experimental sessions.

RESULTS

The results did not indicate significant session vs time interaction effects on popliteal FMD and brachial BP ( P > .05). A subanalysis including only participants with popliteal FMD reduction after the Control session (n = 11) revealed that Breaks enhanced popliteal FMD after 10 min (1.38 ± 6.45% vs -4.87 ± 2.95%, P = .002) and 30 min (-0.43 ± 2.48% vs -2.11 ± 5.22%, P = .047).

CONCLUSION

Breaking up prolonged sitting with IWSE mitigates impaired vascular function resulting from prolonged sitting but has no effect on BP in sedentary adults.

Acute partial sleep restriction does not impact arterial function in young and healthy humans

Habitual short sleep durations are associated with several cardiovascular diseases. Experimental research generally supports these findings as metrics of arterial function are impaired after complete deprivation of sleep and after longer periods of partial sleep restriction. The acute influence of a single instance of partial sleep restriction (PSR), however, has not been defined. We evaluated arterial structure and function among 32 university-aged participants on two occasions: once after normal habitual sleep (NS), and again the morning after an acute partial sleep restriction (PSR) intervention involving only 3 h of sleep for a single night. Endothelial function was measured using ultrasonography at the brachial artery via flow-mediated dilatation (FMD), and a ramp peak oxygen uptake test was used to evaluate cardiorespiratory fitness. Blood samples were collected from a subset of participants to investigate the influence of circulatory factors on cellular mechanisms implicated in endothelial function. Sleep duration was lower after a night of PSR compared to NS (P < 0.001); however, there were no appreciable differences in any haemodynamic outcome between conditions. FMD was not different between NS and PSR (NS: 6.5 ± 2.9%; PSR: 6.3 ± 2.9%; P = 0.668), and cardiorespiratory fitness did not moderate the haemodynamic response to PSR (all P > 0.05). Ex vivo cell culture results aligned with in vivo data, showing that acute PSR does not alter intracellular processes involved in endothelial function. No differences in arterial structure or function were observed between NS and acute PSR in healthy and young participants, and cardiorespiratory fitness does not modulate the arterial response to acute sleep restriction.

Influence of heart failure (HF) comorbidity in chronic obstructive pulmonary disease (COPD) and isolated forms of HF and COPD on cardiovascular function during hospitalization

INTRODUCTION

Coexistence of chronic obstructive pulmonary disease(COPD) and heart failure(HF) is associated with systemic inflammation, myocardial injury, and arterial stiffening, impacting cardiovascular risk and prognosis in patients. Arterial stiffness, reduced nitric oxide synthesis, and altered cardiac autonomic control further link COPD and HF pathophysiology, emphasizing the need for comprehensive cardiovascular assessment.

OBJECTIVE

To investigate a cardiovascular profile in patients hospitalized with exacerbation COPD(ECOPD) in coexistence with HF compared with isolated diseases.

METHODS

A cross-sectional study including patients diagnosed with ECOPD and decompensated HF, approached between 24 and 48 h after hospital admission. Assessments included: endothelial function by brachial artery flow-mediated vasodilation(FMD); hemodynamic through analysis of pulse wave and arterial stiffness by carotid-femoral pulse wave velocity(cfPWV) and cardiac autonomic modulation(CAM) by heart rate variability(HRV).

RESULTS

The mean FMD was 4.45 %, indicating endothelial dysfunction in all patients. Date is present in mean(confidence interval) sequency COPD(n = 12), COPD-HF(n = 21) and HF(n = 21). FMD: 5.47(3.96-6.91); 2.66(0.09-3.48); 4.60(2.30-6.43) p < 0.01. However, COPD-HF had worse FMD. Arterial stiffens (AIx: 29.0(19.0-42.6); 34.6(24.3-43.2); 14.5(8.0-24.0)p < 0.01; cfPWV: (6.5(5.4-7.2); 7.7(7.0-8.5); 6.0(5.0-6.5)); COPD-HF also showed greater activation of the sympathetic nervous system compared to patients with isolated diseases (PNS: 1.32(-2.53 to -0.62); -2.33(-2.60 to -2.12); -1.32(-1.42 to -1.01) p < 0.01; SNS: 3.50(1.40-8.55); 7.11(5.70-8.29); 2.32(1.78-5.01) p < 0.01). In addition, rMSSD, NN50, pNN50, and TINN also indicate worse CAM in the COPD-HF group compared to isolated diseases.

CONCLUSION

During hospitalization, the worst impairment in vascular function and cardiac autonomic modulation were found in patients with COPD and HF comorbidity compared to the isolated diseases(HF or COPD).

New device for assessment of endothelial function: plethysmographic flow-mediated vasodilation (pFMD)

Measurement of flow-mediated vasodilation (FMD) in the brachial artery by using ultrasound is a well-established technique for evaluating endothelial function. To make the measurement quicker and simpler than the measurements of conventional ultrasound FMD (uFMD), we have developed a new noninvasive method, plethysmographic FMD (pFMD), to assess vascular response to reactive hyperemia in the brachial artery. The aim of this study was to determine the accuracy of measurement of pFMD in comparison to that of measurement of conventional uFMD. This study was a multi-center, cross-sectional study. We compared pFMD by a new device using cuff pressure and volume with conventional uFMD using ultrasound in 50 men (mean age, 41 ± 9 years). pFMD significantly correlated with conventional uFMD (β = 0.59, P < 0.001). In Bland-Altman plot analysis of pFMD and conventional uFMD, the mean difference of pFMD and conventional uFMD was 0.78%, and limits of agreement (mean difference ±2 standard deviations of the difference) ranged from -4.53% to 6.11%. We demonstrated validity of the new method for measurement of pFMD, which can automate the evaluation of endothelial function in a short time. Measurement of pFMD is simpler than measurement of conventional uFMD and may have reduced artificial bias compared to that of conventional uFMD measurement (URL for Clinical Trial: https://ethics.hiroshima-u.ac.jp/site/wp-content/uploads/2022/12/eki_giji20221213.pdf . Registration Number for Clinical Trial: E2022-0131).

Endothelial dysfunction influences augmented aortic hemodynamic responses to metaboreflex activation in postmenopausal women

PURPOSE

Postmenopausal women experience augmented aortic hemodynamic responses to isometric handgrip (IHG) exercise and metaboreflex activation post-exercise muscle ischemia (PEMI). Relationships between endothelial function brachial artery flow-mediated dilation (FMD) and aortic stiffness carotid-femoral pulse wave velocity (cfPWV) with aortic pulsatile hemodynamics during IHG and PEMI have not been determined. The relationships between aortic hemodynamic responses to PEMI were evaluated.

METHODS

Aortic blood pressure (BP), wave reflection, and pressure of forward (Pf) and backward (Pb) waves were measured using arterial tonometry at rest, IHG at 30% maximal force, and PEMI in 30 (15/group) postmenopausal women with low (≤ 4.5%) and normal (≥ 5.5%) FMD. Hemodynamic responses were analyzed as the change (Δ) from rest to the last minute of IHG and PEMI.

RESULTS

Brachial and aortic systolic BP (SBP) responses to IHG were higher in the low vs normal FMD group (P < 0.05). Aortic SBP (Δ20 ± 8 vs Δ11 ± 7 mmHg), pulse pressure (PP) (Δ12 ± 8 vs Δ6 ± 4 mmHg), augmented pressure (AP) (Δ5 ± 3 vs Δ2 ± 2 mmHg), and Pb (Δ6 ± 4 vs Δ3 ± 2 mmHg) responses to PEMI were greater (P < 0.05) in women with low vs. normal FMD. FMD was negatively correlated with aortic SBP, PP, AP, and Pb (P < 0.05) responses to PEMI. cfPWV was not correlated with responses to PEMI.

CONCLUSION

Endothelial dysfunction relates to augmented aortic pulsatile load during metaboreflex activation, which may increase cardiovascular risk in postmenopausal women.

Oxidative stress and vascular dysfunction: Potential therapeutic targets and therapies in peripheral artery disease

Peripheral artery disease (PAD) is the manifestation of atherosclerosis characterized by the accumulation of plaques in the arteries of the lower limbs. Interestingly, growing evidence suggests that the pathology of PAD is multifaceted and encompasses both vascular and skeletal muscle dysfunctions, which contributes to blunted physical capabilities and diminished quality of life. Importantly, it has been suggested that many of these pathological impairments may stem from blunted reduction-oxidation (redox) handling. Of note, in those with PAD, excessive production of reactive oxygen species (ROS) outweighs antioxidant capabilities resulting in oxidative damage, which may have systemic consequences. It has been suggested that antioxidant supplementation may be able to assist in handling ROS. However, the activation of various ROS production sites makes it difficult to determine the efficacy of these antioxidant supplements. Therefore, this review focuses on the common cellular mechanisms that facilitate ROS production and discusses how excessive ROS may impair vascular and skeletal muscle function in PAD. Furthermore, we provide insight for current and potential antioxidant therapies, specifically highlighting activation of the Kelch-like ECH-associated protein 1 (Keap1) - Nuclear Factor Erythroid 2-related factor 2 (Nrf2) pathway as a potential pharmacological therapy to combat ROS accumulation and aid in vascular function, and physical performance in patients with PAD. Altogether, this review provides a better understanding of excessive ROS in the pathophysiology of PAD and enhances our perception of potential therapeutic targets that may improve vascular function, skeletal muscle function, walking capacity, and quality of life in patients with PAD.

A comprehensive physics-based model for the brachial Artery's full flow mediated dilation (FMD) response observed during the FMD test

In this study, a physics-based model is developed to describe the entire flow mediated dilation (FMD) response. A parameter quantifying the arterial wall's tendency to recover arises from the model, thereby providing a more elaborate description of the artery's physical state, in concert with other parameters characterizing mechanotransduction and structural aspects of the arterial wall. The arterial diameter's behavior throughout the full response is successfully reproduced by the model. Experimental FMD response data were obtained from healthy volunteers. The model's parameters are then adjusted to yield the closest match to the observed experimental response, hence delivering the parameter values pertaining to each subject. This study establishes a foundation based on which future potential clinical applications can be introduced, where endothelial function and general cardiovascular health are inexpensively and noninvasively quantified.

Flow-mediated dilation facilitates radial artery cannulation in patients undergoing intravenous general anesthesia: A prospective randomized controlled trial

BACKGROUND

Flow-mediated dilation (FMD) is commonly used as a diagnostic tool to assess endothelial function, and compared with other methods for stimulating radial artery dilation, FMD offers several advantages such as non-invasiveness, ease of execution, minimal equipment requirements, and negligible risk. The study aimed to investigate the effect of FMD in facilitating radial arterial cannulation in the context of intravenous general anesthesia.

METHODS

Eighty patients undergoing intravenous general anesthesia and requiring radial artery cannulation were randomized 1:1 to the FMD group and control group. Patients in the FMD group received an upper arm occlusion for 5 min after anesthesia induction, and the cuff was placed without inflation for the equivalent duration in the control group. The primary outcome was first-attempt success rate. Secondary outcomes were the diameter and percentage of dilation of radial artery, overall success rate, total number of attempts, cannulation time, and occurrence of procedure-related complications.

RESULTS

Intravenous anesthetic agents significantly dilated the radial artery (p < 0.05), which was further increased by FMD. An increase in both the first-attempt and overall success rate of radial artery cannulation was demonstrated with the use of FMD (67.5% vs 42.5%, p < 0.05). The total number of attempts needed to cannulate the radial artery was reduced in the FMD group as compared with the control group (p < 0.05), but no differences in cannulation time and procedure-related complications were found between the two groups (p > 0.05).

CONCLUSIONS

FMD induced by a 5-min upper arm occlusion may facilitate radial artery cannulation in patients undergoing intravenous general anesthesia.

Impaired vascular function among young users of anabolic-androgenic steroids

Supraphysiological doses of anabolic-androgenic steroids (AAS) is popular among recreational weightlifters and bodybuilders due to the performance-enhancing properties but is also associated with adverse cardiovascular effects. The knowledge about how AAS affect the vasculature is limited, although results from previous studies suggest alterations in vasoreactivity and morphology. In the present study we investigate the association between long-term use of AAS and vascular function. Hundred and twenty-three males were included in the study, 56 of them current AAS users and 67 weightlifting controls. Vascular function was evaluated by carotid artery reactivity and flow-mediated dilation. AAS users had significantly reduced carotid artery reactivity (p < 0.001) and flow-mediated dilation (p < 0.001) compared to weightlifting controls. Results from the present study indicate that long-term use of AAS affect the cardiovascular system negatively, measured as reduced carotid artery reactivity and flow-mediated dilation. These findings could partly explain sudden cardiovascular events among young long-term users of AAS.

Effects of smoking cessation on endothelial function as assessed by flow-mediated total dilation

BACKGROUND

In assessing the effects of smoking cessation on endothelial function, low-flow-mediated constriction (L-FMC) may provide complementary information to flow-mediated dilation (FMD). However, the value of flow-mediated total dilation (FMTD), an index that incorporates L-FMC into FMD, remains underreported. We aimed to evaluate the effect of smoking cessation on endothelial function, as assessed by FMD and FMTD, and clarify its associated clinical factors.

METHODS

We enrolled 118 consecutive current smokers without previous coronary artery disease (72.9% were men; age: 59 ± 11 years) who underwent smoking cessation treatment. The clinical variables %FMD, %L-FMC, and %FMTD were examined before and 20 weeks after treatment initiation. A multivariate linear regression model was used to investigate the effects of smoking cessation on %FMD and %FMTD and the interaction between smoking cessation and baseline clinical variables.

RESULTS

After 20 weeks, 85 smokers (69.4% were men; age: 59 ± 12 years) ceased smoking (abstainers), whereas 33 smokers (81.8% were men; age: 58 ± 11 years) did not (continued smokers). The estimated group differences (abstainers - continued smokers) in changes in the %FMD and %FMTD were 0.77% (95% confidence interval [CI], -0.22-1.77%; p = 0.129) and 1.17% (95% CI, 0.16-2.18%; p = 0.024), respectively. Smoking cessation-associated improvement in %FMTD was greater in women than in men (5.41% [95% CI, 3.15-7.67%] versus 0.24% [95% CI, -0.81-1.28%]; p-value for interaction, < 0.001). Additionally, a greater %FMTD improvement was observed in patients who smoked fewer cigarettes per day (p-value for interaction, 0.042) and those who had a smaller resting baseline lumen diameter (Dbase) (p-value for interaction, 0.023).

CONCLUSIONS

Smoking cessation was associated with an improvement in %FMTD. Sex, cigarettes smoked per day, and Dbase significantly affected this improvement. The FMTD may help in risk stratification after smoking cessation.

Resistance exercise breaks during prolonged sitting augment the blood flow response to a subsequent oral glucose load in sedentary adults

Sitting-induced impairments in postprandial blood flow are an important link between sedentary behaviour and cardiometabolic disease risk. The objective of this work was to examine the effects of resistance exercise breaks (REB) performed every 30 min during an otherwise sedentary 3-h period on the vasodilatory response to a subsequent oral glucose load in sedentary adults. Twenty-four sedentary adults (27 ± 7 years, 16 females) completed two conditions. Fasting blood glucose, insulin, popliteal artery blood flow (PABF) and gastrocnemius perfusion were measured immediately before standardized breakfast consumption. After breakfast, the 3-h REB or uninterrupted (SIT) intervention period commenced. Participants sat at a workstation, and popliteal artery shear rate (PASR) was measured 60 and 120 min into this period. In the REB condition, participants performed a 3-min REB (3 × [20 s squats, 20 s high knees, 20 s calf raises]) every 30 min. Following the intervention period, baseline measurements were repeated. Participants then consumed a 75 g glucose beverage, and PABF and perfusion were measured every 30-60 min for the following 120 min. Relative to SIT, REB increased PASR at 60 min (+31.4 ± 9.2/s, P = 0.037) and 120 min (+37.4 ± 10.2/s, P = 0.019) into the intervention period. Insulin and glucose increased (P < 0.001) in response to glucose consumption, with no differences between conditions (P ≥ 0.299). In response to the glucose load, perfusion (1.57 vs. 1.11 mL/100 mL/min, P = 0.023) and PABF (+45.3 ± 11.8 mL/min, P = 0.001) were greater after REB versus SIT. Performing 3-min REB every 30 min during an otherwise sedentary 3-h period augmented leg blood flow responses to an oral glucose load. HIGHLIGHTS: What is the central question of this study? Can 3-min resistance exercise breaks (REB) performed during an otherwise sedentary 3-h period augment the vasodilatory response to a subsequent oral glucose load in sedentary adults? What is the main finding and its importance? Performing 3-min REB, which included squats, high knees, and calf raises, every 30 min augmented lower limb blood flow responses to a subsequent oral glucose load compared to 3 h of uninterrupted sitting in sedentary adults. Sitting-induced impairment in postprandial vasodilatory function has been identified as a link between sedentary behaviour and cardiometabolic disease. Thus, the current study presents a potentially effective strategy to offset this risk.

Effects of Single Low-Carbohydrate, High-Fat Meal Consumption on Postprandial Lipemia and Markers of Endothelial Dysfunction: A Systematic Review of Current Evidence

CONTEXT

Postprandial lipemia (PPL) is associated with increased risk of endothelial dysfunction (ED), a precursor of atherosclerotic cardiovascular disease (ASCVD). The effects of low-carbohydrate, high-fat (LCHF) diets on ASCVD risk are uncertain; therefore, gaining a greater understanding of LCHF meals on PPL may provide valuable insights.

OBJECTIVE

The current systematic review investigated the effects of single LCHF meal consumption on PPL and markers of ED.

DATA SOURCES

CINAHL Plus, PubMed, Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for key terms related to endothelial function, cardiovascular disease, glycemia, lipemia, and the postprandial state with no restriction on date.

DATA EXTRACTION

Full-text articles were independently screened by 2 reviewers, of which 16 studies were eligible to be included in the current review. All trials reported a minimum analysis of postprandial triglycerides (PPTG) following consumption of an LCHF meal (<26% of energy as carbohydrate). Results were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

DATA ANALYSIS

Single-meal macronutrient composition was found to play a key role in determining postprandial lipid and lipoprotein responses up to 8 hours post-meal. Consumption of LCHF meals increased PPTG and may contribute to ED via reduced flow-mediated dilation and increased oxidative stress; however, energy and macronutrient composition varied considerably between studies.

CONCLUSION

Consumption of an LCHF meal had a negative impact on PPL based on some, but not all, single-meal studies; therefore, the contribution of LCHF meals to cardiometabolic health outcomes remains unclear. Further research is needed on specific categories of LCHF diets to establish a causal relationship between postprandial modulation of lipids/lipoproteins and impaired vascular endothelial function.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD 42023398774.

Flow-mediated dilation is modified by exercise training status during childhood and adolescence: preliminary evidence of the youth athlete's artery

Chronic exercise training is associated with an "athlete's artery" phenotype in young adults and an attenuated age-related decline in endothelium-dependent arterial function. Adolescence is associated with an influx of sex-specific hormones that may exert divergent effects on endothelial function, but whether training adaptations interact with biological maturation to produce a "youth athlete's artery" has not been explored. We investigated the influence of exercise-training status on endothelium-dependent arterial function during childhood and adolescence. Brachial artery flow-mediated dilation (FMD) was assessed in n = 102 exercise-trained (males, n = 25; females, n = 29) and untrained (males, n = 23; females, n = 25) youths, characterized as pre (males, n = 25; females, n = 26)- or post (males, n = 23; females, n = 28)-predicted age at peak height velocity (PHV). Baseline brachial artery diameter was larger in post- compared with pre-PHV youths (P ≤ 0.001), males compared with females (P ≤ 0.001), and trained compared with untrained youths (3.26 ± 0.51 vs. 3.11 ± 0.42 mm; P = 0.041). Brachial FMD was similar in pre- and post-PHV youths (P = 0.298), and males and females (P = 0.946). However, exercise-trained youths demonstrated higher FMD when compared with untrained counterparts (5.3 ± 3.3 vs. 3.0 ± 2.6%; P ≤ 0.001). Furthermore, brachial artery diameter (r2 = 0.142; P = 0.007 vs. r2 = 0.004; P = 0.652) and FMD (r2 = 0.138; P = 0.008 vs. r2 = 0.003; P = 0.706) were positively associated with cardiorespiratory fitness in post-, but not pre-PHV youths, respectively. Collectively, our data indicate that exercise training is associated with brachial artery remodeling and enhanced endothelial function during youth. However, arterial remodeling and endothelium-dependent function are only associated with elevated cardiorespiratory fitness during later stages of adolescence.NEW & NOTEWORTHY We report preliminary evidence of the "youth athlete's artery," characterized by training-related arterial remodeling and elevated endothelium-dependent arterial function in children and adolescents. However, training-related adaptations in brachial artery diameter and flow-mediated dilation (FMD) were associated with cardiorespiratory fitness in adolescents, but not in children. Our findings indicate that endothelium-dependent arterial function is modifiable with chronic exercise training during childhood, but the association between FMD and elevated cardiorespiratory fitness is only apparent during later stages of adolescence.

Circulating catecholamines, endothelin-1, and nitric oxide releases do not explain the preserved FMD following acute resistance exercise in strength-trained men

PURPOSE

Acute resistance exercise decreases endothelial function in sedentary individuals but not in strength-trained (ST) individuals. However, the underlying mechanism(s) of vascular protection in ST individuals remains unclear. Herein, we compared catecholamines, endothelin-1 (ET-1), and nitric oxide (NOx) releases after acute resistance exercise between sedentary and ST individuals.

METHODS

The untrained (UT) group comprised 12 male individuals with no regular training, while the ST group comprised 12 male individuals. Participants performed a session of resistance exercise, which consisted of 3 sets of 10 repetitions at 75% of one repetition maximum. Heart rate (HR) and blood pressure were measured during resistance exercise. Brachial artery flow-mediated dilation (FMD), blood pressure, HR, and blood collection were undertaken before and 10, 30, and 60 min after the resistance exercise.

RESULTS

No significant difference was found in baseline brachial artery FMD between the groups (P > 0.05). Brachial artery FMD was significantly reduced in the UT group (P < 0.05) but it was prevented in the ST group after the resistance exercise. Significant differences were found at 10, 30, and 60 min after the resistance exercise in brachial artery ΔFMD from baseline between groups (P < 0.05). Blood pressure, HR, plasma epinephrine, norepinephrine, dopamine, serum endothelin-1, and plasma NOx responses did not differ between groups throughout the experimental period.

CONCLUSION

In conclusion, preserved endothelial function in response to acute resistance exercise in ST male individuals is independent of catecholamines, ET-1, and NOx responses.

Are all sugars equal? Role of the food source in physiological responses to sugars with an emphasis on fruit and fruit juice

High (free) sugar intakes can increase self-reported energy intake and are associated with unfavourable cardiometabolic health. However, sugar source may modulate the effects of sugars due to several mechanisms including the food matrix. The aim of this review was to assess the current state of evidence in relation to food source effects on the physiological responses to dietary sugars in humans relevant to cardiometabolic health. An additional aim was to review potential mechanisms by which food sources may influence such responses. Evidence from meta-analyses of controlled intervention trials was used to establish the balance of evidence relating to the addition of sugars to the diet from sugar-sweetened beverages, fruit juice, honey and whole fruit on cardiometabolic outcomes. Subsequently, studies which have directly compared whole fruit with fruit juices, or variants of fruit juices, were discussed. In summary, the sources of sugars can impact physiological responses, with differences in glycaemic control, blood pressure, inflammation, and acute appetite. Longer-term effects and mechanisms require further work, but initial evidence implicates physical structure, energy density, fibre, potassium and polyphenol content, as explanations for some of the observed responses.

Sitting knee-flexion angle does not influence endothelial-dependent vasodilation in laboratory or free-living conditions

INTRODUCTION

Single bouts of prolonged bent-legged sitting attenuate popliteal endothelial-dependent vasodilation (as assessed via flow-mediated dilation [FMD]), which is partially attributed to arterial 'kinking'. However, the impact of knee-flexion angle on sitting-induced popliteal FMD is unknown. The objective of this study was to perform separate laboratory and free-living studies to test the hypotheses that: (1) popliteal FMD impairments would be graded between knee flexions at 90° (bent-legged sitting) > 45° > 0° (straight-legged sitting) following a 3-hour bout of sitting; and (2) more habitual time spent bent-legged sitting (< 45°) would be associated with lower FMD.

METHODS

The laboratory study included eight young, healthy adults (24 ± 2 years; four women) who underwent two sitting bouts over 2 days with one leg positioned at a knee-flexion angle of 0° or 90° and the opposite leg at 45° knee flexion. Popliteal FMD was assessed at pre- and postsitting timepoints.

RESULTS

Sitting-induced reductions in FMD were similar between all knee-flexion angles (all, p > 0.674). The free-living study included 35 young, healthy adults (23 ± 3 years; 16 women) who wore three activPAL monitors (torso, thigh, shin) to determine detailed sedentary postures. Time spent sedentary (624 ± 127 min/day), straight-legged sitting (112 ± 98 min/day), and bent-legged sitting (442 ± 106 min/day) were not related to relative FMD (5.3 ± 1.8%; all, p > 0.240).

CONCLUSION

These findings suggest that knee-flexion angle-mediated arterial 'kinking' during sitting is not a major contributor toward sitting-induced popliteal endothelial-dependent vasodilatory dysfunction.

COVID-19 in the Initiation and Progression of Atherosclerosis: Pathophysiology During and Beyond the Acute Phase

The incidence of atherosclerotic cardiovascular disease is increasing globally, especially in low- and middle-income countries, despite significant efforts to reduce traditional risk factors. Premature subclinical atherosclerosis has been documented in association with several viral infections. The magnitude of the recent COVID-19 pandemic has highlighted the need to understand the association between SARS-CoV-2 and atherosclerosis. This review examines various pathophysiological mechanisms, including endothelial dysfunction, platelet activation, and inflammatory and immune hyperactivation triggered by SARS-CoV-2 infection, with specific attention on their roles in initiating and promoting the progression of atherosclerotic lesions. Additionally, it addresses the various pathogenic mechanisms by which COVID-19 in the post-acute phase may contribute to the development of vascular disease. Understanding the overlap of these syndromes may enable novel therapeutic strategies. We further explore the need for guidelines for closer follow-up for the often-overlooked evidence of atherosclerotic cardiovascular disease among patients with recent COVID-19, particularly those with cardiometabolic risk factors.

Nadir blood pressure responses to longer consecutive cardiac cycle sequences absent of sympathetic bursts are associated with popliteal endothelial-dependent dilation

PURPOSE

The nadir pressure responses to cardiac cycles absent of muscle sympathetic nerve activity (MSNA) bursts (or non-bursts) are typically reported in studies quantifying sympathetic transduction, but the information gained by studying non-bursts is unclear. We tested the hypothesis that longer sequences of non-bursts (≥8 cardiac cycles) would be associated with a greater nadir diastolic blood pressure (DBP) and that better popliteal artery function would be associated with an augmented reduction in DBP.

METHODS

Resting beat-by-beat DBP (via finger photoplethysmography) and common peroneal nerve MSNA (via microneurography) were recorded in 39 healthy, adults (age 23.4 ± 5.3 years; 19 females). For each cardiac cycle absent of MSNA bursts, the mean nadir DBP (ΔDBP) during the 12 cardiac cycles following were determined, and separate analyses were conducted for ≥8 or < 8 cardiac cycle sequences. Popliteal artery endothelial-dependent (via flow-mediated dilation; FMD) and endothelial-independent vasodilation (via nitroglycerin-mediated dilation; NMD) were determined.

RESULTS

The nadir DBP responses to sequences ≥8 cardiac cycles were larger (-1.40 ± 1.27 mmHg) than sequences <8 (-0.38 ± 0.46 mmHg; p < 0.001). In adjusting for sex and burst frequency (14 ± 8 bursts/min), larger absolute or relative FMD (p < 0.01), but not NMD (p > 0.53) was associated with an augmented nadir DBP. This overall DBP-FMD relationship was similar in sequences ≥8 (p = 0.04-0.05), but not <8 (p > 0.72).

CONCLUSION

The DBP responses to non-bursts, particularly longer sequences, were inversely associated with popliteal endothelial function, but not vascular smooth muscle sensitivity. This study provides insight into the information gained by quantifying the DBP responses to cardiac cycles absent of MSNA.

Remote and local effects of ischemic preconditioning on vascular function: a case for cumulative benefit

Brief, repeated cycles of limb ischemia and reperfusion [ischemic preconditioning (IPC)] can protect against vascular insult. Few papers have considered the effect of IPC on resting vascular function, and no single study has simultaneously considered the local (trained arm) and remote (untrained arm) effects of a single session of IPC and following repeated sessions. We determined macrovascular [allometrically scaled flow-mediated dilation (FMD)] and microvascular [cutaneous vascular conductance (CVC)] function in healthy adults before, immediately post, 20 min post, and 24 h post a single session of IPC (4 × 5 min of single arm ischemia). These outcomes also were remeasured 24 h after six IPC sessions, performed over 2 wk. FMD and CVC increased in both arms 20 min post [FMD mean difference (MD) 1.1%, P < 0.001; CVC MD 0.08 arbitrary units (AU), P = 0.004] but not 24 h post (FMD MD -0.2%, P = 0.459; CVC MD -0.02 AU, P = 0.526] a single session of IPC, with no differences between trained and untrained arms. Although FMD did not increase 24 h after one IPC session, it was elevated in both arms 24 h after the sixth session (MD 1.2%, P = 0.009). CVC was not altered in either arm 24 h after the last IPC session. These data indicate that the local and remote effects of IPC on vascular health may be equivalent and that the benefits to FMD may be greater with sustained training compared with a single IPC exposure.

Enhancing flow-mediated dilation analysis by optimizing an open-source software with automated edge detection

Flow-mediated dilation (FMD) is a common measure of endothelial function and an indicator of vascular health. Automated software methods exist to improve the speed and accuracy of FMD analysis. Compared with commercial software, open-source software offers similar capabilities at a much lower cost while allowing for increased customization specific to users' needs. We introduced modifications to an existing open-source software, FloWave.us to better meet FMD analysis needs. The purpose of this study was to compare the repeatability and reliability of the modified FloWave.us software to the original software and to manual measurements. To assess these outcomes, duplex ultrasound imaging data from the popliteal artery in older adults were analyzed. The average percent FMD for the modified software was 6.98 ± 3.68% and 7.27 ± 3.81% for observer 1 and 2 respectively, compared with 9.17 ± 4.91% and 10.70 ± 4.47% with manual measurements and 5.07 ± 31.79% with the original software for observer 1. The modified software and manual methods demonstrated higher intraobserver intraclass correlation coefficients (ICCs) for repeated measures for baseline diameter, peak diameter, and percent FMD compared with the original software. For percent FMD, the interobserver ICC was 0.593 for manual measurements and 0.723 for the modified software. With the modified method, an average of 97.7 ± 2.4% of FMD videos frames were read, compared with only 17.9 ± 15.0% frames read with the original method when analyzed by the same observer. Overall, this work further establishes open-source software as a robust and viable tool for FMD analysis and demonstrates improved reliability compared with the original software.NEW & NOTEWORTHY This study improves edge detection capabilities and implements noise reduction strategies to optimize an existing open-source software's suitability for flow-mediated dilation (FMD) analysis. The modified software improves the precision and reliability of FMD analysis compared with the original software algorithm. We demonstrate that this modified open-source software is a robust tool for FMD analysis.

Advancements in risk stratification and management strategies in primary cardiovascular prevention

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of morbidity and mortality worldwide, highlighting the urgent need for advancements in risk assessment and management strategies. Although significant progress has been made recently, identifying and managing apparently healthy individuals at a higher risk of developing atherosclerosis and those with subclinical atherosclerosis still poses significant challenges. Traditional risk assessment tools have limitations in accurately predicting future events and fail to encompass the complexity of the atherosclerosis trajectory. In this review, we describe novel approaches in biomarkers, genetics, advanced imaging techniques, and artificial intelligence that have emerged to address this gap. Moreover, polygenic risk scores and imaging modalities such as coronary artery calcium scoring, and coronary computed tomography angiography offer promising avenues for enhancing primary cardiovascular risk stratification and personalised intervention strategies. On the other hand, interventions aiming against atherosclerosis development or promoting plaque regression have gained attention in primary ASCVD prevention. Therefore, the potential role of drugs like statins, ezetimibe, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, omega-3 fatty acids, antihypertensive agents, as well as glucose-lowering and anti-inflammatory drugs are also discussed. Since findings regarding the efficacy of these interventions vary, further research is still required to elucidate their mechanisms of action, optimize treatment regimens, and determine their long-term effects on ASCVD outcomes. In conclusion, advancements in strategies addressing atherosclerosis prevention and plaque regression present promising avenues for enhancing primary ASCVD prevention through personalised approaches tailored to individual risk profiles. Nevertheless, ongoing research efforts are imperative to refine these strategies further and maximise their effectiveness in safeguarding cardiovascular health.