near-infrared-spectroscopy-during-reactive-hyperemia-for-assessment

Near-Infrared Spectroscopy During Reactive Hyperemia for the Assessment of Lower Limb Vascular Function 

Vascular diseases of the lower limb contribute substantially to the&#160;global burden of cardiovascular disease and comorbidities such as diabetes. ...

University of the Sunshine Coast

Peripheral arterial disease (PAD) is characterised by impaired leg blood flow, which contributes to claudication and reduced exercise capacity. This study investigated to what extent vasoactive enzymes might contribute to altered blood flow in PAD (Fontaine stage II).

Vasoactive enzymes and blood flow responses to passive and active exercise in peripheral arterial disease.

Intermittent claudication (IC) is the most commonly reported symptom of peripheral arterial disease (PAD). Impaired limb blood flow is a major casual factor of lower exercise tolerance in PAD but cannot entirely explain it. We hypothesized that IC is associated with structural changes of the capillary-mitochondria interface that could contribute to the reduction of exercise tolerance in IC patients. Capillary and mitochondrial morphometry were performed after light and transmission electron microscopy using vastus lateralis muscle biopsies of 14 IC patients and 10 age-matched controls, and peak power output (PPO) was determined for all participants using an incremental single-leg knee-extension protocol. Capillary density was lower (411 ± 90 mm(-2) vs. 506 ± 95 mm(-2); P ≤ 0.05) in the biopsies of the IC patients than in those of the controls. The basement membrane (BM) around capillaries was thicker (543 ± 82 nm vs. 423 ± 97 nm; P ≤ 0.01) and the volume density of mitochondria was lower (3.51 ± 0.56% vs. 4.60 ± 0.74%; P ≤ 0.01) in the IC patients than the controls. In the IC patients, a higher proportion of capillaries appeared with collapsed slit-like lumen and/or swollen endothelium. PPO was lower (18.5 ± 9.9 W vs. 33.5 ± 9.4 W; P ≤ 0.01) in the IC patients than the controls. We suggest that several structural alterations in skeletal muscle, either collectively or separately, contribute to the reduction of exercise tolerance in IC patients.

Capillary ultrastructure and mitochondrial volume density in skeletal muscle in relation to reduced exercise capacity of patients with intermittent claudication.

Aging is often associated with reduced leg blood flow, increased arterial stiffness, and endothelial dysfunction, all of which are related to declining nitric oxide (NO) bioavailability. Flow mediated dilatation (FMD) and passive leg movement (PLM) hyperaemia are two techniques used to measure NO-dependent vascular function. We hypothesised that acute dietary nitrate (NO) supplementation would improve NO bioavailability, leg FMD, and PLM hyperaemia. Fifteen healthy older men (69 ± 4 years) attended two experiment sessions and consumed either 140 mL of concentrated beetroot juice (800 mg NO) or placebo (NO-depleted beetroot juice) in a randomised, double blind, cross-over design study. Plasma nitrite (NO) and NO, blood pressure (BP), augmentation index (AIx75), pulse wave velocity (PWV), FMD of the superficial femoral artery, and PLM hyperaemia were measured immediately before and 2.5 h after consuming NO and placebo. Placebo had no effect but NO led to an 8.6-fold increase in plasma NO, which was accompanied by an increase in FMD (NO: +1.18 ± 0.94% vs. placebo: 0.23 ± 1.13%,  = 0.002), and a reduction in AIx75 (NO: -8.7 ± 11.6% vs. placebo: -4.6 ± 5.5%,  = 0.027). PLM hyperaemia, BP, and PWV were unchanged during both trials. This study showed that a dose of dietary NO improved NO bioavailability and enhanced endothelial function as measured by femoral artery FMD. These findings provide insight into the specific central and peripheral vascular responses to dietary NO supplementation in older adults.

Acute Dietary Nitrate Supplementation Improves Flow Mediated Dilatation of the Superficial Femoral Artery in Healthy Older Males.

The benefits of exercise for patients with cancer are well-established, however, for patients with bone metastases, exercise as adjuvant therapy is underutilised due to concerns for safety, efficacy and other barriers such as the method of delivery. This scoping review explores these barriers by reviewing the results of clinical trials conducted on participants with bone metastases.

Exercise Intervention for Bone Metastasis: Safety, Efficacy and Method of Delivery.

Prostate cancer survivors treated with androgen deprivation therapy may be at increased risk of cardiovascular disease. Dietary recommendations for the prevention and/or management of cardiovascular disease for these individuals are lacking. This review synthesizes the evidence on the effect of dietary interventions on cardiometabolic biomarkers and cardiovascular disease risk in prostate cancer survivors receiving androgen deprivation therapy. A systematic review was conducted across PubMed, CINAHL, Embase, and Cochrane CENTRAL. Intervention or observational cohort studies evaluating diets, nutrients, or nutraceuticals with or without concurrent exercise interventions on cardiovascular disease, cardiovascular events, or cardiovascular disease biomarkers in those treated with androgen deprivation therapy were included. Confidence in the body of evidence was appraised using Grading of Recommendations, Assessment, Development and Evaluations. Twelve studies reported across fifteen papers were included. Interventions were heterogenous, with most studies including an exercise co-intervention (n = 8). Few significant findings for the effects of diet on cardiometabolic markers were likely due to weak methodology and sample sizes. Strongest evidence was for the effect of a healthy Western dietary pattern with exercise on improved blood pressure (Confidence: moderate). The healthy Western dietary pattern with exercise may improve high-density lipoprotein cholesterol (Confidence: Low) and flow-mediated dilation. Soy may improve total cholesterol (Confidence: Very low). A low-carbohydrate diet with physical activity may improve high-density lipoprotein cholesterol, incidence of metabolic syndrome, and Framingham cardiovascular disease risk score. Evidence of the effect of dietary interventions on cardiometabolic biomarkers and cardiovascular disease risk of prostate cancer survivors receiving androgen deprivation therapy is insufficient to inform practice. Well-designed dietary interventions aimed at improving cardiometabolic outcomes of this population are warranted to inform future dietary recommendations.

The effect of dietary interventions or patterns on the cardiometabolic health of individuals treated with androgen deprivation therapy for prostate cancer: A systematic review.

Meegan Walker

VasoActive Research Group,
School of Health,
VasoActive Research Group, School of Health

University of the Sunshine Coast

Near-Infrared Spectroscopy During Reactive Hyperemia for the Assessment of Lower Limb Vascular Function

Meegan Walker

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University of the Sunshine Coast

Near-Infrared Spectroscopy During Reactive Hyperemia for the Assessment of Lower Limb Vascular Function

VasoActive Research Group,
School of Health,
VasoActive Research Group, School of Health