Improvements in vascular function in response to acute lower limb heating in young healthy males and females

Author(s):  
Jem L. Cheng ◽  
Jennifer S. Williams ◽  
Sven Hoekstra ◽  
Maureen J. MacDonald

Regular exposure to passive heat stress improves vascular function, but the optimal heating prescription remains undefined. Local limb heating is more feasible than whole body heating, but the evidence demonstrating its efficacy is lacking. The purpose of this study was to determine whether acute improvements in vascular function can be achieved with lower limb heating in 16 young healthy individuals (8 female, 8 male). In separate visits, participants underwent 45-min of ankle- and knee-level hot water immersion (45 °C). A subset of 7 participants also participated in a time-control visit. Endothelial function was assessed through simultaneous brachial and superficial femoral artery flow-mediated dilation (FMD) tests. Macrovascular function was quantified by %FMD, while microvascular function was quantified by vascular conductance during reactive hyperemia. Arterial stiffness was assessed through carotid-femoral and femoral-foot pulse wave velocity (PWV). Plasma concentrations of interleukin-6 and extracellular heat shock protein-72 (eHSP72) were used as indicators of inflammation. Our findings showed that 45-min of lower limb heating - regardless of condition - acutely improved upper limb macrovascular endothelial function (i.e., brachial %FMD; Pre: 4.6±1.7 vs. Post: 5.4±2.0%; P=0.004) and lower limb arterial stiffness (i.e., femoral-foot PWV; Pre: 8.4±1.2 vs. Post: 7.7±1.1 m/s; P=0.011). However, only knee-level heating increased upper limb microvascular endothelial function (i.e., brachial peak vascular conductance; Pre: 6.3±2.7 vs. Post: 7.8±3.5 ml/min⋅mmHg; P≤0.050) and plasma eHSP72 concentration (Pre: 12.4±9.4 vs. Post: 14.8±9.8 ng/ml; P≤0.050). These findings show that local lower limb heating acutely improves vascular function in younger individuals, with knee-level heating improving more outcome measures.

2017 ◽  
Vol 312 (3) ◽  
pp. R281-R291 ◽  
Author(s):  
Kate N. Thomas ◽  
André M. van Rij ◽  
Samuel J. E. Lucas ◽  
James D. Cotter

Passive heat induces beneficial perfusion profiles, provides substantive cardiovascular strain, and reduces blood pressure, thereby holding potential for healthy and cardiovascular disease populations. The aim of this study was to assess acute responses to passive heat via lower-limb, hot-water immersion in patients with peripheral arterial disease (PAD) and healthy, elderly controls. Eleven patients with PAD (age 71 ± 6 yr, 7 male, 4 female) and 10 controls (age 72 ± 7 yr, 8 male, 2 female) underwent hot-water immersion (30-min waist-level immersion in 42.1 ± 0.6°C water). Before, during, and following immersion, brachial and popliteal artery diameter, blood flow, and shear stress were assessed using duplex ultrasound. Lower-limb perfusion was measured also using venous occlusion plethysmography and near-infrared spectroscopy. During immersion, shear rate increased ( P < 0.0001) comparably between groups in the popliteal artery (controls: +183 ± 26%; PAD: +258 ± 54%) and brachial artery (controls: +117 ± 24%; PAD: +107 ± 32%). Lower-limb blood flow increased significantly in both groups, as measured from duplex ultrasound (>200%), plethysmography (>100%), and spectroscopy, while central and peripheral pulse-wave velocity decreased in both groups. Mean arterial blood pressure was reduced by 22 ± 9 mmHg (main effect P < 0.0001, interaction P = 0.60) during immersion, and remained 7 ± 7 mmHg lower 3 h afterward. In PAD, popliteal shear profiles and claudication both compared favorably with those measured immediately following symptom-limited walking. A 30-min hot-water immersion is a practical means of delivering heat therapy to PAD patients and healthy, elderly individuals to induce appreciable systemic (chronotropic and blood pressure lowering) and hemodynamic (upper and lower-limb perfusion and shear rate increases) responses.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Georgia Siasou ◽  
Gerasimos Siasos ◽  
Marilita M Moschos ◽  
Nikolaos Gouliopoulos ◽  
Evangelos Oikonomou ◽  
...  

Introduction: Primary open-angle glaucoma (POAG) is one of the most prevalent causes of irreversible blindness and is associated with endothelial dysfunction and arterial stiffness. Pseudoexfoliative glaucoma (PEG) is another type of glaucoma observed in pseudoexfoliation syndrome. It is characterized by the deposition of pseudoexfoliative material not only to the anterior segment of the eye, but also to the vessels, heart and other organs. Hypothesis: Endothelial function and arterial stiffness are impaired in patients with POAG and PEG supporting the significant role of vascular function impairment in the progression of the disease. Methods: Forty four POAG patients, 22 PEG and 38 healthy subjects (Cl) were included in this study. All subjects were free of cardiovascular or inflammatory diseases. Endothelial function was evaluated by flow-mediated dilatation (FMD). Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) as a measure of arterial wave reflections Results: Between the three study groups CL, POAG, PEG there was no difference in age (67±10years vs. 70±9years vs. 66±12yeras, p=0.12) or prevalence of male sex (70% vs. 57% vs. 50%, p=0.21). Importantly, there was a linear impairment of FMD (7.35±2.77% vs. 6.58±3.18% vs. 4.88±3.29%, p=0.006), PWV (7.98±1.56m/sec vs. 9.20±1.84m/sec vs. 9.22±2.16m/sec, p=0.004) and AIx (21.29±8.77% vs. 25.14±5.71% vs. 28.20±8.75%, p=0.002) from CL to POAG and PEG. Interestingly post hoc test after Scheffe correction revealed also that PEG subjects had not only significantly impaired FMD, compared to control subjects, but also compared to POAG subjects (4.88±3.29% vs. 6.58±3.18%, p=0.02). Conclusions: Endothelial function and arterial stiffness are significantly impaired in patients with pseudoexfoliative glaucoma. These findings shed some light in the pathophysiology of pseudoexfoliative glaucoma and support the theory that pseudoexfoliative fibrils may also accumulate and damage the arterial wall.


Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Sangeetha D Nathaniel ◽  
Shane McGinty ◽  
David G Edwards ◽  
William B Farquhar ◽  
Melissa A Witman ◽  
...  

The mechanisms for the benefits of Angiotensin Receptor Neprilysin inhibitor (ARNi) in heart failure patients with reduced ejection fraction (HFrEF) are likely beyond blood pressure (BP) reduction. Vascular function, a prognostic marker in HFrEF, improves with ARNi in animal models. Improvements in vascular function may contribute to benefits from ARNi in HFrEF; however, this has yet to be demonstrated in humans. The purpose of the study was to test the hypothesis that arterial stiffness and endothelial function would improve after 12 weeks of ARNi in HFrEF. Methods: HFrEF participants with NYHA class II-III were enrolled from local cardiology clinics and completed experimental visits at baseline and 12 weeks later: 13 participants were prescribed ARNi by their cardiologist [62±10 years, Men: 10, BMI: 30±5 kg/m 2 , EF: 28±6 %; Non-ischemic cardiomyopathy (NICM): 8], 10 participants continued on conventional treatment [CON: 60±7 years, Men: 6, BMI: 31±6 kg/m 2 , EF: 31±5 % and NICM: 4; all P=NS]. During each experimental visit, arterial stiffness was assessed via carotid-femoral pulse wave velocity (PWV; Sphygmocor PVx system) and endothelial function by brachial artery flow-mediated dilation (FMD) using standard techniques. Statistical analyses were performed using 2x2 repeated-measures ANOVA. Results: Baseline mean BP (MAP) was similar between ARNi (93±14 mmHg) and CON (85 ± 10 mmHg; P=0.13); MAP tended to decrease after 12 weeks of ARNi (88 ± 11 mmHg; P=0.08) but not CON (90 ± 17 mmHg; P=0.14) (ANOVA interaction P=0.03). PWV tended to be higher at baseline in ARNi (8.8 ± 2.5 m/s) compared to CON (7.0 ± 2.5 m/s; P=0.09); PWV decreased after 12 weeks of ARNi (7.0 ± 1.7 m/s; P<0.01) and was unchanged in CON (7.4 ± 2.4 m/s; P=0.33) (ANOVA interaction P<0.01). When controlling for MAP, the effect of ARNi on PWV remained (P<0.01). At baseline, FMD was similar between ARNi (2.81 ± 2.05%) and CON (4.75 ± 3.75%; P=0.13); however, FMD increased after 12 weeks of ARNi (5.73 ± 1.87%; P<0.001) but not in CON (5.37 ± 3.38%; P=0.33) (ANOVA time P<0.001, interaction P=0.01). Conclusion: ARNi improves arterial stiffness and endothelial function in HFrEF. Understanding the mechanisms of ARNi in HFrEF is crucial as it may pave the way for better interventions in other cardiovascular diseases.


2019 ◽  
Vol 44 (12) ◽  
pp. 1383-1386
Author(s):  
Andrew W. D’Souza ◽  
Sean R. Notley ◽  
Robert D. Meade ◽  
Glen P. Kenny

Lower-limb intermittent sequential pneumatic compression (ISPC) improves circulation and vascular function in elderly adults. We evaluated the hypothesis that ISPC would also augment whole-body heat loss (WBHL) in elderly adults (aged 69 ± 4 years) resting in extreme heat (40 °C). While ISPC increased mean arterial pressure (91 ± 9 mm Hg) relative to no-ISPC (83 ± 5 mm Hg; P = 0.013) at the end of the exposure, no influence on WBHL was observed (81 ± 7 and 86 ± 11 W for ISPC and no-ISPC, respectively, P = 0.310). Novelty When assessed in elderly adults during an extreme heat exposure, intermittent sequential pneumatic compression augmented mean arterial pressure but did not enhance whole-body heat loss.


Temperature ◽  
2016 ◽  
Vol 3 (2) ◽  
pp. 286-297 ◽  
Author(s):  
Kate N. Thomas ◽  
André M. van Rij ◽  
Samuel J.E. Lucas ◽  
Andrew R. Gray ◽  
James D. Cotter

2017 ◽  
Vol 117 (3) ◽  
pp. 1070-1083 ◽  
Author(s):  
Catherine R. Lowrey ◽  
Joseph Y. Nashed ◽  
Stephen H. Scott

An important aspect of motor control is the ability to perform tasks with the upper limbs while maintaining whole body balance. However, little is known about the coordination of upper limb voluntary and whole body postural control after mechanical disturbances that require both upper limb motor corrections to attain a behavioral goal and lower limb motor responses to maintain whole body balance. The present study identified the temporal organization of muscle responses and center of pressure (COP) changes following mechanical perturbations during reaching. Our results demonstrate that muscle responses in the upper limb are evoked first (∼50 ms), with lower limb muscle activity occurring immediately after, in as little as ∼60 ms after perturbation. Hand motion was immediately altered by the load, while COP changes occurred after ∼100 ms, when lower limb muscle activity was already present. Our secondary findings showed that both muscle activity and COP changes were influenced by behavioral context (by altering target shape, circle vs. rectangle). Voluntary and postural actions initially directed the hand toward the center of both target types, but after the perturbation upper limb and postural responses redirected the hand toward different spatial locations along the rectangle. Muscle activity was increased for both upper and lower limbs when correcting to the circle vs. the rectangle, and these differences emerged as early as the long-latency epoch (∼75–120 ms). Our results demonstrate that postural responses are rapidly and flexibly altered to consider the behavioral goal of the upper limb. NEW & NOTEWORTHY The present work establishes that, when reaching to a target while standing, perturbations applied to the upper limb elicit a rapid response in lower limb muscles. Unlike voluntary movements, postural responses do not occur before corrections of the upper limb. We show the first evidence that corrective postural adjustments are modulated by upper limb behavioral context (target shape). Importantly, this indicates that postural responses take into account upper limb feedback for online control.


2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Andrew J. Degnan ◽  
Nandini Shah ◽  
David M. Carty ◽  
John R. Petrie ◽  
Christian Delles ◽  
...  

Background. Peripheral arterial tonometry (PAT) is a novel, non-invasive and operator-independent method for simultaneous assessment of endothelial function and arterial stiffness. We examined the repeatability of PAT in females and the influence of the estrous cycle. Methods. In 14 healthy female and five healthy male control subjects, PAT was performed on three separate occasions with 10 days between visits. Reactive hyperemia index (RHI), a measure of endothelial function, and peripheral augmentation index (AIx), a measure of arterial stiffness, were determined with the EndoPAT-2000 system. Intraclass correlation coefficient (ICC) was calculated as a measure of repeatability. Results. In both female and male groups, RHI and AIx did not differ between the three measurements (all n.s. by 1-way ANOVA). In females, reanalyzing the data after taking phase of estrous cycle into account had no effect on the results. Repeatability for RHI and AIx in females (ICC for RHI = 0.43, ICC for AIx = 0.78) was similar to that in male subjects (ICC for RHI = 0.42, ICC for AIx = 0.63). Conclusions. PAT measurements were not affected by the estrous cycle in females, and repeatability was comparable to that in males. This should facilitate inclusion of female subjects into vascular function studies using PAT.


2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 58-58
Author(s):  
Lea Tischmann ◽  
Tanja Adam ◽  
Ronald Mensink ◽  
Peter Joris

Abstract Objectives Soy foods may contribute to the beneficial effects of plant-based diets on cardiovascular disease (CVD) risk. However, their effects on vascular function have hardly been investigated. The objective was to investigate if longer-term soy nut consumption improves vascular function and cardiometabolic health in older adults. Methods Twenty-three apparently healthy participants (60–70 years; BMI between 20–30 kg/m2) participated in a randomized, controlled, single-blinded cross-over trial with an intervention (67 g of soy nuts daily providing 25.5 g soy protein) and control period (no nuts) of 16 weeks, separated by eight weeks wash-out. Volunteers followed the Dutch food-based dietary guidelines. At baseline and at 8 and 16 weeks anthropometric measurements and fasting blood samples were collected. Markers of vascular function (i.e., endothelial function, arterial stiffness, and microvascular structure) were assessed at week 16. Results No serious adverse events were reported and the soy nut regime was well tolerated. Body weight remained stable. Serum isoflavone concentrations, a marker of compliance, increased after the intervention period (daidzein: 128.3 ng/mL; 95% CI: 72.6–183.9 ng/mL; P &lt; 0.001 and genistein: 439.8 ng/mL 95% CI: 246.7–632.9 ng/mL; P &lt; 0.001). The brachial artery flow-mediated vasodilation (FMD) response increased by 1.49 pp (95% CI: 0.03–2.95 pp; P = 0.046) following the soy intervention, but no effect was found on the carotid artery reactivity (CAR) response. Arterial stiffness, assessed by carotid-to-femoral pulse wave velocity (PWVc-f), was unchanged. Retinal arteriolar calibers (CRAE), a measure for microvascular structure, tended to improve by 1.42 mm (95% CI: −0.05–2.90 mm; P = 0.059). Soy consumption also lowered serum LDL-cholesterol concentrations by 0.17 mmol/L (95% CI: 0.02–0.32 mmol/L; P = 0.027). HDL-cholesterol and triacylglycerol (TAG) did not change. Finally, office SBP and DBP decreased by 4 mmHg (95% CI: 0–8 mmHg; P = 0.034) and 2 mmHg (95% CI: 1–4 mmHg; P = 0.005), respectively. Conclusions A longer-term daily intake of soy nuts improved endothelial function, office blood pressure, and serum LDL-cholesterol concentrations, suggesting mechanisms by which an increased soy food intake beneficially affects CVD risk in older adults. Funding Sources This study was supported by a grant from the Alpro Foundation.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Nikolaos Gouliopoulos ◽  
Gerasimos Siasos ◽  
Marilita Moschos ◽  
Dimitrios Tousoulis ◽  
Evangelos Oikonomou ◽  
...  

Introduction: Diabetic Retinopathy (DR) is a complication of diabetes mellitus (DM) leading to deterioration of vision. Hypothesis: We investigated the possible association of vascular function and inflammation with visual acuity in subjects with DM. Methods: We enrolled 100 consecutive subjects with DM. Patients were divided in those with DR (53 subjects, mean age 68±9) and those with no evidence of DR (NDR) (mean age 66±6). The diagnosis of DR was made by ophthalmoscopy and best-corrected visual acuity (BCVA) was measured in both eyes. A BCVA less than 0.8 was considered as severely impaired. Endothelial function was evaluated by flow mediated dilation (FMD) in the brachial artery and arterial stiffness was evaluated by carotid femoral pulse wave velocity (PWV). C reactive protein (CRP) and interleukin 6 (IL6) levels were measured. Results: Patients with DR compared to NDR patients had impaired FMD (3.42±1.08% vs. 5.39±1.47%, p<0.001), impaired PWV (11.10±3.11m/sec vs. 9.02±2.13m/sec, p=0.001) and worse BCVA (p<0.001). Moreover in DM subjects, BCVA was positively correlated with FMD, creatinine clearance, and inversely correlated with PWV, glycosylated hemoglobin levels, C- reactive protein levels, IL6 levels, age and with duration of diabetes mellitus (p<0.01 for all). Interestingly, after adjustment for age, smoking habits and the aforementioned confounders, FMD, IL6 levels, DM duration and male gender were independently associated with BCVA (p<0.05 for all). Moreover, ROC curve analysis revealed that both impaired FMD (AUC=0.79, p<0.001) and PWV (AUC=0.8, p<0.001) have a significant diagnostic ability in detecting diabetic subjects with severely impaired BCVA. More precisely, FMD less than 4.5% has a sensitivity of 90% and a specificity of 60%, while PWV over 10.0 m/sec has a sensitivity of 83% and a specificity of 68%, for the diagnosis of severely impaired BCVA. Conclusion: Patients with DR have significantly impaired visual acuity witch is associated with impaired vascular function and inflammation. Moreover, both endothelial function and arterial stiffness were high sensitivity predictors of visual impairment highlighting their potential role on the prevention and management of the complications in diabetes mellitus.


2018 ◽  
Vol 124 (3) ◽  
pp. 573-582 ◽  
Author(s):  
I. Mark Olfert ◽  
Evan DeVallance ◽  
Hannah Hoskinson ◽  
Kayla W. Branyan ◽  
Stuart Clayton ◽  
...  

Proponents for electronic cigarettes (E-cigs) claim that they are a safe alternative to tobacco-based cigarettes; however, little is known about the long-term effects of exposure to E-cig vapor on vascular function. The purpose of this study was to determine the cardiovascular consequences of chronic E-cig exposure. Female mice (C57BL/6 background strain) were randomly assigned to chronic daily exposure to E-cig vapor, standard (3R4F reference) cigarette smoke, or filtered air ( n = 15/group). Respective whole body exposures consisted of four 1-h-exposure time blocks, separated by 30-min intervals of fresh air breaks, resulting in intermittent daily exposure for a total of 4 h/day, 5 days/wk for 8 mo. Noninvasive ultrasonography was used to assess cardiac function and aortic arterial stiffness (AS), measured as pulse wave velocity, at three times points (before, during, and after chronic exposure). Upon completion of the 8-mo exposure, ex vivo wire tension myography and force transduction were used to measure changes in thoracic aortic tension in response to vasoactive-inducing compounds. AS increased 2.5- and 2.8-fold in E-cig- and 3R4F-exposed mice, respectively, compared with air-exposed control mice ( P < 0.05). The maximal aortic relaxation to methacholine was 24% and 33% lower in E-cig- and 3R4F-exposed mice, respectively, than in controls ( P < 0.05). No differences were noted in sodium nitroprusside dilation between the groups. 3R4F exposure altered cardiac function by reducing fractional shortening and ejection fraction after 8 mo ( P < 0.05). A similar, although not statistically significant, tendency was also observed with E-cig exposure ( P < 0.10). Histological and respiratory function data support emphysema-associated changes in 3R4F-exposed, but not E-cig-exposed, mice. Chronic exposure to E-cig vapor accelerates AS, significantly impairs aortic endothelial function, and may lead to impaired cardiac function. The clinical implication from this study is that chronic use of E-cigs, even at relatively low exposure levels, induces cardiovascular dysfunction. NEW & NOTEWORTHY Electronic cigarettes (E-cigs) are marketed as safe, but there has been insufficient long-term exposure to humans to justify these claims. This is the first study to report the long-term in vivo vascular consequences of 8 mo of exposure to E-cig vapor in mice (equivalent to ~25 yr of exposure in humans). We report that E-cig exposure increases arterial stiffness and impairs normal vascular reactivity responses, similar to other risk factors, including cigarette smoking, which contribute to the development of cardiovascular disease.


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