Regulation of myogenesis and skeletal muscle regeneration: effects of oxygen levels on satellite cell activity

Reduced oxygen (O-2) levels (hypoxia) are present during embryogenesis and exposure to altitude and in pathologic conditions. During embryogenesis, myogenic progenitor cells reside in a hypoxic microenvironment, which may regulate their activity. Satellite cells are myogenic progenitor cells localized in a local environment, suggesting that the O-2 level could affect their activity during muscle regeneration. In this review, we present the idea that O-2 levels regulate myogenesis and muscle regeneration, we elucidate the molecular mechanisms underlying myogenesis and muscle regeneration in hypoxia and depict therapeutic strategies using changes in O-2 levels to promote muscle regeneration. Severe hypoxia (<= 1% O-2) appears detrimental for myogenic differentiation in vitro, whereas a 3-6% O-2 level could promote myogenesis. Hypoxia impairs the regenerative capacity of injured muscles. Although it remains to be explored, hypoxia may contribute to the muscle damage observed in patients with pathologies associated with hypoxia (chronic obstructive pulmonary disease, and peripheral arterial disease). Hypoxia affects satellite cell activity and myogenesis through mechanisms dependent and independent of hypoxia inducible factor-1 alpha. Finally, hyperbaric oxygen therapy and transplantation of hypoxia-conditioned myoblasts are beneficial procedures to enhance muscle regeneration in animals. These therapies may be clinically relevant to treatment of patients with severe muscle damage.-Chaillou, T. Lanner, J. T. Regulation of myogenesis and skeletal muscle regeneration: effects of oxygen levels on satellite cell activity.