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We propose a new VO2max test using a progressive staged protocol on an Assault Fitness AssaultBike. Twelve healthy males performed a traditional ramp cycle ergometer test (TRAD) and a progressively staged AssaultBike protocol (AB) in a counterbalanced order. AB elicited higher immediate post-exercise lactate, absolute and relative VO2max, and maximum heart rate than TRAD (P = 0.006, P = 0.014, P = 0.007, and P = 0.001, respectively). The protocol outlined herein may provide a more accurate assessment of VO2max due to greater skeletal muscle mass recruitment that is more representative of the whole body. [ABSTRACT FROM AUTHOR]

Aim: We compared the impact of artificially- and sugar-sweetened beverages co-ingested with a mixed meal on postprandial fat and carbohydrate oxidation, blood glucose, and plasma insulin and triglyceride concentrations. Methods: Eight college-aged, healthy males completed three randomly assigned trials, which consisted of a mixed macronutrient meal test with 20oz of Diet-Coke (AS), Coca-Cola (NS), or water (CON). One week separated each trial and each participant served as his own control. Resting energy expenditure (REE) via indirect calorimetry, blood pressure, and blood samples were obtained immediately before, 5, 10, 30, 60, 120, and 180 min after meal and beverage ingestion. A two-way (treatment × time) repeated-measures ANOVA was conducted to assess REE, fat and carbohydrate oxidation rates, blood glucose, and plasma insulin and triglyceride concentrations. Results: There was a significant main effect of treatment on total fat oxidation (P = 0.006), fat oxidation was significantly higher after AS (P = 0.006) and CON (P = 0.001) compared to following NS. There was a significant main effect of treatment on total carbohydrate oxidation (P = 0.005), carbohydrate oxidation was significantly lower after AS (P = 0.014) and CON (P = 0.001) compared to following NS. Plasma insulin concentration AUC was significantly lower after AS (P = 0.019) and trended lower in CON (P = 0.054) compared to following NS. Conclusion: Ingestion of a mixed meal with an artificially-sweetened beverage does not impact postprandial metabolism, whereas a sugar-sweetened beverage suppresses fat oxidation and increases carbohydrate oxidation compared to artificially-sweetened beverage and water. [ABSTRACT FROM AUTHOR]

This study investigated the effects of a novel high-protein diet template on postprandial metabolism and body composition (e.g., waist and hip circumference, body fat (%), fat mass, fat-free mass) in recreationally resistance-trained females. Fifteen females adhered to an eight-week high-protein dietary intervention (~1.5-1.6 g·kg-1·day-1) administered via template format. Pre- and post-intervention visits included anthropometrics, measurement of body composition, and an acute high-fat meal challenge. The high-fat meal challenge (61% fat) consisted of fasting postprandial blood glucose, resting metabolic rate (RMR), fat and carbohydrate oxidation assessed at 60-, 120-, and 180-minutes. Participants were split into high (HTF; 5-6 days ·week-1 of resistance training; n = 8) and low-training frequency (LTF; 2-3 days ·week-1 of resistance training; n = 7) groups. All metabolism data were assessed as absolute (kcal or g) and relative (kcal or g·kg·FFM-1·minutes-1) to fat-free mass. Post-intervention, there was a significant reduction in HTF waist circumference (p = 0.044), LTF body fat % (p = 0.012), and LTF fat mass (p = 0.014). Post-intervention, HTF females had significantly lower absolute RMR area under the curve (AUC) than LTF females (p = 0.036). LTF females had higher absolute fat oxidation AUC compared to HTF females' pre-intervention (p = 0.048) but a significant decrease in absolute (p = 0.050) and relative (p = 0.050) fat oxidation AUC post-intervention. LTF females had a significant increase in absolute (p = 0.032) and relative (p = 0.029) carbohydrate oxidation AUC pre- to post-intervention (p = 0.032). For blood glucose, no significant differences between groups were detected (p > 0.05). These findings suggest that a novel high-protein diet template elicits a metabolic shift favoring carbohydrate oxidation in females engaging in low-frequency resistance training but did not alter fat and carbohydrate metabolism in females engaging in HTF resistance training. [ABSTRACT FROM AUTHOR]

Patients with obesity and diabetes mellitus exhibit a high prevalence of cardiac diastolic dysfunction (DD), an independent predictor of cardiovascular events for which no evidence-based treatment exists. In light of renin-angiotensinaldosterone system activation in obesity and the cardioprotective action of mineralocorticoid receptor (MR) antagonists in systolic heart failure, we examined the hypothesis that MR blockade with a blood pressure-independent low-dose spironolactone (LSp) would treat obesity-associated DD in the Zucker obese (ZO) rat. Treatment of ZO rats exhibiting established DD with LSp normalized cardiac diastolic function, assessed by echocardiography. This was associated with reduced cardiac fibrosis, but not reduced hypertrophy, and restoration of endothelium-dependent vasodilation of isolated coronary arterioles via a nitric oxide-independent mechanism. Further mechanistic studies revealed that LSp reduced cardiac oxidative stress and improved endothelial insulin signaling, with no change in arteriolar stiffness. Infusion of Sprague-Dawley rats with the MR agonist aldosterone reproduced the DD noted in ZO rats. In addition, improved cardiac function in ZO-LSp rats was associated with attenuated systemic and adipose inflammation and an anti-inflammatory shift in cardiac immune cell mRNAs. Specifically, LSp increased cardiac markers of alternatively activated macrophages and regulatory T cells. ZO-LSp rats had unchanged blood pressure, serum potassium, systemic insulin sensitivity, or obesity-associated kidney injury, assessed by proteinuria. Taken together, these data demonstrate that MR antagonism effectively treats established obesity-related DD via blood pressure-independent mechanisms. These findings help identify a particular population with DD that might benefit from MR antagonist therapy, specifically patients with obesity and insulin resistance. [ABSTRACT FROM AUTHOR]

Abstract: Background: Exercise training elevates circulating irisin and induces the expression of the FNDC5 gene in skeletal muscles of mice. Our objective was to determine whether exercise training also increases FNDC5 protein or mRNA expression in the skeletal muscles of pigs as well as plasma irisin. Methods: Castrated male pigs of the Rapacz familial hypercholesterolemic (FHM) strain and normal (Yucatan miniature) pigs were sacrificed after 16–20weeks of exercise training. Samples of cardiac muscle, deltoid and triceps brachii muscle, subcutaneous and epicardial fat were obtained and FNDC5 mRNA, along with that of 6 other genes, was measured in all tissues of FHM pigs by reverse transcription polymerase chain reaction. FNDC protein in deltoid and triceps brachii was determined by Western blotting in both FHM and normal pigs. Citrate synthase activity was measured in the muscle samples of all pigs as an index of exercise training. Irisin was measured by an ELISA assay. Results: There was no statistically significant effect of exercise training on FNDC5 gene expression in epicardial or subcutaneous fat, deltoid muscle, triceps brachii muscle or heart muscle. Exercise-training elevated circulating levels of irisin in the FHM pigs and citrate synthase activity in deltoid and triceps brachii muscle. A similar increase in citrate synthase activity was seen in muscle extracts of exercise-trained normal pigs but there was no alteration in circulating irisin. Conclusion: Exercise training in pigs does not increase FNDC5 mRNA or protein in the deltoid or triceps brachii of FHM or normal pigs while increasing circulating irisin only in the FHM pigs. These data indicate that the response to exercise training in normal pigs is not comparable to that seen in mice. [Copyright &y& Elsevier]

Abstract: Objective: There is debate as to whether fibronectin type III domain containing 5 (FNDC5) and its protein product irisin are therapeutic targets for obesity-associated maladies. Thus, we sought to examine FNDC5 mRNA within skeletal muscle of obese/diabetic-prone Otsuka Long-Evans Tokushima Fatty (OLETF) rats versus lean/healthy Long Evans Tokushima Otsuka (LETO) rats. We hypothesized that FNDC5 expression would be greater in obese (OLETF) versus lean (LETO) animals. Materials/Methods: Triceps muscle of 30–32week old OLETF and LETO rats were assayed for FNDC5 and PGC1α mRNA levels. Body composition and circulating biomarkers of the OLETF and LETO rats were also correlated with skeletal muscle FNDC5 mRNA expression patterns in order to examine potential relationships that may exist. Results: OLETF rats exhibited twice the amount of triceps FNDC5 mRNA compared to LETO rats (p<0.01). Significant positive correlations existed between triceps muscle FNDC5 mRNA expression patterns versus fat mass (r=0.70, p=0.008), as well as plasma leptin (r=0.82, p<0.001). PGC1α mRNA levels were also highly correlated with FNDC5 mRNA (r=0.85, p<0.001). In subsequent culture experiments, low and high physiological doses of leptin had no effect on PGC1α mRNA or FNDC5 mRNA levels in C2C12 myotubes. Paradoxically, circulating irisin concentrations tended to be higher in a second cohort of LETO versus OLETF rats (p=0.085). Conclusion: These results reveal a positive association between total body adiposity and skeletal muscle FNDC5 gene expression. Of interest, circulating irisin levels tended to be lower in OLETF rats. Further research is needed to examine whether other adipose tissue-derived factors up-regulate FNDC5 transcription and/or inhibit irisin biosynthesis from FNDC5. [Copyright &y& Elsevier]

The article presents a study on the effect of disturbed blood flow on the release of endothelial microparticles (EMPs) from the human vascular endothelium. It notes that geometrically irregular arterial regions tend to be in a state of disturbed blood flow and exhibit marked susceptibility to atherosclerosis development. Findings show that disturbed blood flow leads to endothelial activation and apoptosis. It adds that results provide evidence of endothelial injury due to disturbed blood flow.

Abstract: Insulin-like growth factor binding protein–1 (IGFBP-1) has metabolic effects throughout the body, and its expression is regulated in part by insulin. Circulating IGFBP-1 predicts development of cardiometabolic diseases in longitudinal studies, and low IGFBP-1 concentrations are associated with insulin resistance and consumption of a high-fat diet. Because of the favorable metabolic effects of regular aerobic exercise, we hypothesized that aerobic exercise training would increase plasma IGFBP-1 concentrations and attenuate the reduction in IGFBP-1 after a high-fat meal. Ten overweight (body mass index = 28.7 ± 0.9 kg/m2), older (61 ± 2 years) men and women underwent high-fat feeding and oral glucose tolerance tests at baseline and after 6 months of aerobic exercise training. In response to aerobic exercise training, subjects increased cardiorespiratory fitness by 13% (P < .05) and insulin sensitivity index by 28% (P < .05). Basal plasma concentrations of IGFBP-1 increased by 41% after aerobic exercise training (P < .05). The insulin response to an oral glucose tolerance test was a significant predictor of fasting plasma IGFBP-1 concentrations at baseline and after exercise training (P = .02). In response to the high-fat meal at baseline, plasma IGFBP-1 concentrations decreased by 58% (P < .001); a 61% decrease to similar postprandial concentrations was observed after exercise training (P < .001). Plasma insulin response to the high-fat meal was inversely associated with postprandial IGFBP-1 concentrations at baseline and after exercise training (P = .06 and P < .05, respectively). Although aerobic exercise training did not attenuate the response to a high-fat meal, the increase in IGFBP-1 concentrations after exercise training may be one mechanism by which exercise reduces risk for cardiometabolic diseases in older adults. [Copyright &y& Elsevier]

The article looks at the advantages of regular physical activity in enhancing the cardiovascular regenerative potentials of circulating angiogenic cells (CAC). The authors believe that exercise could influence CAC characteristics which in turn could improve vascular health and prevent cardiovascular diseases. It is also inferred that acute exercise could enhance endothelial function in patients with heart failure and contribute to vasculogenesis due to the emergence of new populations of cells.

Abstract: Fetuin-A is a liver-derived factor that may play a role in insulin resistance and age-related chronic diseases (eg, type 2 diabetes mellitus and cardiovascular [CV] disease). Regular exercise improves CV risk and insulin sensitivity; however, it is unknown whether chronic exercise training is related to circulating levels of fetuin-A. Therefore, this study examined whether plasma fetuin-A levels were related to age and chronic physical activity in men. We hypothesized that chronic physical activity would be related to lower plasma fetuin-A levels in younger and older men. In healthy high-active (HI) and low-active (LO) young (HI, n = 7; LO, n = 8) and older (HI, n = 12, LO, n = 11) men, we determined cardiorespiratory fitness (maximal oxygen uptake), plasma fetuin-A levels, plasma insulin, insulin resistance (homeostasis model assessment of insulin resistance), and the standard risk factors for CV disease. Groups were matched for body mass index. Fetuin-A was significantly higher (∼20%) in both young and older LO men compared with their HI counterparts, and fetuin-A was inversely related to maximal oxygen uptake (r = −0.40, P = .014). Plasma fetuin-A levels showed trends to be significantly correlated with insulin (r = -0.34, P = .052) and homeostasis model assessment of insulin resistance (r = 0.33, P = .058) in the older individuals. In younger participants, fetuin-A was related to blood pressure and cholesterol measures. These results indicate that low levels of fetuin-A are related to cardiorespiratory fitness and a number of conventional CV and metabolic disease risk factors independent of age and body mass index. Therefore, the maintenance of low levels of circulating fetuin-A may be a novel mechanism contributing to enhanced insulin sensitivity with regular physical activity. [ABSTRACT FROM AUTHOR]