Effects of obesity and acute resistance exercise on skeletal muscle angiogenic communication pathways.

New Findings: What is the central question of this study? Do obesity and acute resistance exercise alter the regulation of muscle intercellular communication pathways consistent with inadequate compensatory angiogenesis in response to muscle loading present in individuals with obesity? What is the main finding and its importance? Obesity is associated with differences in both pro- and anti-angiogenic signalling consistent with lower muscle capillarization. Acute resistance exercise increases the release of skeletal muscle small extracellular vesicles independent of body mass. These results identify new cellular factors associated with impaired angiogenesis in obesity and the positive effects of acute resistance exercise in lean and obese skeletal muscle.

Skeletal muscle IGF-1 is lower at rest and after resistance exercise in humans with obesity.

Purpose: Obesity is associated with numerous changes in skeletal muscle including greater muscle mass and muscle fiber cross sectional area (FCSA), yet fasted muscle protein synthesis is lower. Activation of the IGF-1/Akt/mTOR pathway is critical for muscle mass maintenance, muscle hypertrophy, and muscle protein regulation. Resistance exercise (RE) increases muscle mass, FCSA, and IGF-1.

High Incomplete Skeletal Muscle Fatty Acid Oxidation Explains Low Muscle Insulin Sensitivity in Poorly Controlled T2D.

Context: Almost 50% of type 2 diabetic (T2D) patients are poorly controlled [glycated hemoglobin (HbA1c) ≥ 7%]; however, the mechanisms responsible for progressively worsening glycemic control are poorly understood. Lower skeletal muscle mitochondrial respiratory capacity is associated with low insulin sensitivity and the development of T2D.

Objective: We investigated if skeletal muscle insulin sensitivity (SI) was different between well-controlled T2D (WCD) and poorly controlled T2D (PCD) and if the difference was associated with differences resulting from mitochondrial respiratory function.