Apoptosis in skeletal muscle and its relevance to atrophy.

Apoptosis is necessary for maintaining the integrity of proliferative tissues, such as epithelial cells of the gastrointestinal system. The role of apoptosis in post mitotic tissues, such as skeletal muscle, is less well defined. Apoptosis during muscle atrophy occurs in both myonuclei and other muscle cell types. Apoptosis of myonuclei likely contributes to the loss of muscle mass, but the mechanisms underlying this process are largely unknown. Caspase-dependent as well as -independent pathways have been implicated and the mode by which atrophy is induced likely determines the apoptotic mechanisms that are utilized. It remains to be determined whether a decrease in apoptosis will alleviate atrophy and distinct research strategies may be required for different causes of skeletal muscle loss.