The role of Igf-1 on Muscle Wasting: a Therapeutic Approach

While much has been learned about skeletal muscle formation in the embryo, less is known about the molecular pathways controlling skeletal myocyte survival and plasticity in the adult. Tissue remodelling is an important physiological process which allows skeletal muscle to respond to environmental demands. In particular, the complex contractile properties of skeletal muscle depend upon a heterogeneous population of myofibers that confer the functional plasticity necessary to modulate responses to a wide range of external factors, including physical activity, change in hormone levels and motor-neuron activity, oxygen and nutrients supply. Fiber type is an essential determinant of muscle function and alteration in fiber composition represents a major component in muscle wasting associated with muscle diseases. In this context, the prolongation of skeletal muscle strength in aging and neuromuscular disease has been the objective of numerous studies employing a variety of approaches. To date however, efforts to prevent or attenuate age- or disease-related muscle degeneration have been largely unsuccessful. In this context, where direct therapeutic approaches to redress the primary disease are still sub-optimal, it may be more effective to focus on strategies for improving skeletal muscle function. In this review we will discuss the potential therapeutic role of Insulin-like Growth Factor 1 (IGF-1) in treatment of muscle wasting associated with several muscle diseases.