Marcus Vinicius Machado

Structural and functional microvascular alterations in a rat model of metabolic syndrome induced by a high‐fat diet

To investigate microvascular alterations in an experimental model of metabolic syndrome induced by a high‐fat diet (HFD) associated with salt supplementation (0.5% NaCl).

Effect of 12 weeks of training on critical velocity and maximal lactate steady state in swimmers

Abstract The aim of this study was to determine the effect of 12 weeks of training on the critical velocity and maximal lactate steady state of elite swimmers. The tests to determine critical velocity and maximal lactate steady state were performed before and after 12 weeks of training. Critical velocity after 12 weeks of training was significantly higher than before training (1.45±0.10 m · s−1 vs. 1.41±0.11 m · s−1). In contrast, no significant differences in the velocity at maximal lactate steady state were observed before and after training (1.41±0.10 m · s−1 vs. 1.43±0.10 m · s−1). There was also a decrease in mean lactate concentration after 12 weeks of training. Before training, the velocity at maximal lactate steady state occurred at 100% of critical velocity, with a mean lactate concentration of 4.34 mmol · l−1. After training, the velocity at maximal lactate steady state occurred at 98% of critical velocity, with a reduced mean lactate concentration of 3.69 mmol · l−1. Based on these results, it would appear that 12 weeks of training was enough to promote an increase in critical velocity. Although no significant differences in the velocity at maximal lactate steady state were observed before and after training, the decrease in mean lactate concentration after training demonstrated greater efficiency of the aerobic system, leading to less wear during the tests.

High, but not low, exercise volume shifts the balance of renin-angiotensin system toward ACE2/Mas receptor axis in skeletal muscle in obese rats

Metabolic syndrome is a cluster of metabolic risk factors that is linked to central obesity, elevated blood pressure, insulin resistance (IR), and dyslipidemia, where the renin-angiotensin system (RAS) may provide a link among them. This study aimed to evaluate volume exercise effects comparing low vs. high volume of chronic aerobic exercise on RAS axes in skeletal muscle in a diet-induced obesity (DIO) rat model. For this, male Wistar-Kyoto rats were fed a standard chow (SC) diet or a high-fat (HF) diet for 32 wk. Animals receiving the HF diet were randomly divided into low exercise volume (LEV, 150 min/wk) and high exercise volume (HEV, 300 min/wk) at the 20th week. After 12 wk of aerobic treadmill training, the body mass and composition, blood pressure, glucose and lipid metabolism, RAS axes, insulin signaling, and inflammatory pathway were performed. HEV slowed the body mass gain, reduced intra-abdominal fat pad and leptin levels, improved total and peripheral body composition and inflammatory cytokine, reduced angiotensin II type 1 receptor expression, and increased Mas receptor protein expression compared with the HF animals. Sedentary groups (SC and HF) presented lower time to exhaustion and maximal velocity compared with the LEV and HEV groups. Both exercise training groups showed reduced resting systolic blood pressure and heart rate, improved glucose tolerance, IR, insulin signaling, and lipid profile. We conclude that the HEV, but not LEV, shifted the balance of RAS toward the ACE2/Mas receptor axis in skeletal muscle, presenting protective effects against the DIO model.

Exercise training dose differentially alters muscle and heart capillary density and metabolic functions in an obese rat with metabolic syndrome

What is the central question of this study? Regular exercise is recommended as a non‐pharmacological approach for the prevention and treatment of metabolic syndrome. However, the impact of different combinations of intensity, duration and frequency of exercise on metabolic syndrome and microvascular density has not been reported. What is the main finding and its importance? We provide evidence on the impact of aerobic exercise dose on metabolic and microvascular alterations in an experimental model of metabolic syndrome induced by high‐fat diet. We found that the exercise frequency and duration were the main factors affecting anthropometric and metabolic parameters and microvascular density in the skeletal muscle. Exercise intensity was related only to microvascular density in the heart.

Central Sympathetic Modulation Reverses Microvascular Alterations in a Rat Model of High-Fat Diet-Induced Metabolic Syndrome.

The objective of this study was to investigate the role of the SNS on hemodynamic, metabolic, and microvascular alterations in a rat model of HFD‐induced MS with salt supplementation.