Physical activity-induced remodeling of vasculature in skeletal muscle: role

This manuscript summarizes/discusses adaptations of skeletal muscle vasculature induced by 25 physical activity and applies this understanding to benefits of exercise in prevention and treatment of type 26 2 diabetes (T2D). Arteriolar trees of skeletal muscle are heterogeneous. Exercise training increases 27 capillary exchange and blood flow capacities. The distribution of vascular adaptation to different types of 28 exercise training are influenced by muscle fiber type composition and fiber recruitment patterns that 29 produce different modes of exercise. Thus, training-induced adaptations of vascular structure and 30 vascular control in skeletal muscle are not homogeneously distributed throughout skeletal muscle or along 31 the arteriolar tree within a muscle. Results summarized indicate that similar principles apply to vascular 32 adaptation in skeletal muscle in T2D. It is concluded that exercise training induced changes in 33 vascular gene expression differ along the arteriolar tree and by skeletal muscle fiber type 34 composition. Results suggest that it is unlikely that hemodynamic forces are the only exercise35 induced signals mediating the regulation of vascular gene expression. In patients with T2D, 36 exercise training is perhaps the most effective treatment of the many related symptoms. Training-induced 37 changes in the vasculature and in insulin signaling in the muscle fibers and vasculature augment glucose 38 and insulin delivery as well as glucose uptake. If these adaptions occur in a sufficient amount of muscle 39 mass, exposure to hyperglycemia and hyperinsulinemia will decrease along with the risk of microvascular 40 complications throughout the body. It is postulated that exercise sessions in programs of sufficient 41 duration, that engage as much skeletal muscle mass as possible and recruit as many muscle fibers within 42 each muscle as possible, will produce the greatest benefit. The added benefit of combined resistance and 43 aerobic training programs and of high intensity exercise programs is not simply “more exercise is better”. 44 45 by 10.0.33.1 on A ril 9, 2017 http://jaysiology.org/ D ow nladed fom