Models of Sarcopenia

This chapter offers an introduction to sarcopenia and the current methods used to investigate sarcopenia both in people and experimental systems. Sarcopenia refers to the loss of muscle mass during normal aging. The medical importance of sarcopenia lies in the significant loss of muscle strength that accompanies the loss of muscle mass. The cause of sarcopenia is unknown, but there is evidence from human and experimental animals for multiple theories, including loss of motor neurons, oxidative stress, decline in catabolic hormones, increase in inflammatory cytokines, and inadequate nutrition. Changes in muscle protein synthesis and turnover could account for at least part of the loss of muscle mass and strength during aging. Although studies have suggested that there are no changes in overall muscle synthesis, there seem to be selective changes in specific muscle proteins. Vertebrate muscles contain satellite cells that are quiescent myoblasts that have the ability to proliferate, differentiate, and fuse together to form new muscle fibers.