Hypoxic exercise training elicits the mobilization of hematopoietic progenitor cells and endothelial precursor cells into the peripheral blood compartment in healthy men

Abstract

Bone marrow‐derived, circulating endothelial progenitor cells (EPC) is contributing to the maintenance of endothelial function and organ perfusion by mechanisms ranging from endothelial repair to postnatal angiogenesis and vasculogenesis. This study investigates how hypoxic exercise training influences the mobilization of EPC subsets into the peripheral blood compartment. Fifteen sedentary healthy men cycled on an ergometer at about 60% of maximal oxygen consumption under 15%O2 condition for 40 minutes per day, 5 days per week for 5 weeks. Our results indicated that acute 12%O2 exercise increased the mobilization of hematopoietic stem cells (CD34+/KDR+/CD117+), early EPC (CD34+/KDR+/CD133+), and endothelial precursor cells (CEP, CD34+/KDR+/CD133−) into the peripheral blood compartment at pre‐training stage. Moreover, both resting and 12%O2 exercise‐mobilized circulating HSC and CEP levels were significantly elevated following 5 weeks of 15%O2 exercise training. However, no significant changes in circulating (CD34+/KDR+/CD31+) and shedding endothelial cells (KDR+/CD31+/phosphotidylserine+) levels occurred following acute or chronic hypoxic exercise. Hence, we conclude that long‐term moderate‐intensity exercise at 15%O2 environment elicits the mobilization of hematopoietic progenitor cells, especially HSC and CEP, into the peripheral blood compartment, which may facilitate angiogenesis or vasculogenesis in exercising muscles.