What makes vessels grow with exercise training?
Exercise and muscle contractions create a powerful stimulus for structural remodeling of the vasculature. An increase in flow velocity through a vessel increases shear stress, a major stimulus for enlargement of conduit vessels. This leads to an endothelial-dependent, nitric oxide-dependent enlargement of the vessel. Increased flow within muscle, in the absence of contractions, leads to an enhanced capillarity by intussusceptive angiogenesis, a process of capillary splitting by intraluminal longitudinal divide. In contrast, sprouting angiogenesis requires extensive endothelial cell proliferation, with degradation of the extracellular matrix to permit migration and tube formation. This occurs during muscle adaptations to chronic contractions and/or muscle overload. The angiogenic growth factor VEGF appears to be an important element in angiogenesis. Recent advances in research have identified hemodynamic and mechanical stimuli that upregulate angiogenic processes, demonstrated a complexity of potent growth factors and interactions with their corresponding receptors, detected an interaction of cellular signaling events, and identified important tissue reorganization processes that must be coordinated to effect vascular remodeling. It is likely that much of this information is applicable to the vascular remodeling that occurs in response to exercise and/or muscle contractions.
Prior
Barry M
BM
Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri 65211, USA.
Yang
H T
HT
Terjung
Ronald L
RL
D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D001808:Blood Vessels / Q000254:growth & development*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D040542:Mechanotransduction, Cellular / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000502:physiology*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010806:Physical Education and Training / Q000379:methods; D010809:Physical Fitness / Q000502:physiology*; D013314:Stress, Mechanical