Regulation of muscle atrophy: wasting away from the outside in: an introduction

Whereas it is clear that periods of detraining, disuse, injury and aging are marked by losses in skeletal muscle mass and function, the emerging literature suggests that there are unique molecular signaling alterations depending on the perturbation. Understanding the phenotypical adaptations in skeletal muscle and factors that are thought to promote or inhibit genes involved in the atrophy program will elucidate how the muscular system responds to decreases in activity. Recent advances in the discipline have identified specific and innovative methods to promote skeletal muscle hypertrophy including gene therapy, pharmacological, and nutritional interventions. The same success has not been met concerning attenuating skeletal muscle atrophy. If novel approaches are to be implemented in humans to mitigate disuse- and age-related skeletal muscle loss, it is imperative that we evaluate critical regulators of skeletal muscle atrophy from a system to the cellular level. The symposium "Regulation of Muscle Atrophy: Wasting Away from the Outside In" was presented at the ACSM Annual Meeting in Indianapolis on May 29, 2008, to provide an overview of the skeletal muscle atrophy literature and our current understanding of the atrophy program from the whole system to the molecular level. In addition, this symposium addressed the feasibility of intervening with specific countermeasures to attenuate atrophy. This introduction identifies the scope of the symposium, which evaluates our current understanding of the atrophy program and how this information can facilitate the development of effective countermeasures.