Exercise Training Stimulates the Release of Glutathione Peroxidase 1 (GPX1)-Enriched Extracellular Vesicles That...

An acute bout of high intensity exercise can transiently increase circulating extracellular vesicles (EVs) that possess beneficial molecular cargo. However, no studies to date have comprehensively evaluated plasma quantity, protein content, and function of EVs collected from blood after multiple bouts of endurance exercise. Here we demonstrate that 4 weeks of voluntary wheel running increases plasma EV quantity when collected immediately after the last bout of training in mice. These EVs (ExerVs) are enriched in oxidoreductases, including the antioxidant glutathione peroxidase 1 (GPX1). Repeated, systemic injections of ExerVs into sedentary recipient mice twice per week for 4 weeks did not alter mitochondrial content or function, fiber size, or fiber type, but increased capillary density and perfusion in skeletal muscle. ExerVs also stimulated tube formation and branch lengthening in vitro and improved the recovery of capillary content after a period of disuse in vivo. ExerVs isolated from GPX1^-/- mice lacked the ability to stimulate vessel formation, whereas GPX1-encapsulated liposomes robustly increased capillary growth, both in vitro and in vivo. The results from this study suggest that circulating ExerVs positively impact vascular structure and function in skeletal muscle in a manner that may be dependent on GPX1.