Myosatellite Cell - Function in Muscle Repair

Function in Muscle Repair

When muscle cells undergo injury, quiescent satellite cells are released from beneath the basement membrane. They become activated and re-enter the cell cycle. These dividing cells are known as the "transit amplifying pool" before undergoing myogenic differentiation to form new (post-mitotic) myotubes. There is also evidence suggesting that these cells are capable of fusing with existing myofibers to facilitate growth and repair.

The process of muscle regeneration involves considerable remodeling of extracellular matrix and, where extensive damage occurs, is incomplete. Fibroblasts within the muscle deposit scar tissue, which can impair muscle function, and is a significant part of the pathology of muscular dystrophies.

Satellite cells proliferate following muscle trauma and form new myofibers through a process similar to foetal muscle development. After several cell divisions, the satellite cells begin to fuse with the damaged myotubes and undergo further differentiations and maturation, with peripheral nuclei as in hallmark. One of the first roles described for IGF-1 was its involvement in the proliferation and differentiation of satellite cells. In addition, IGF-1 expression in skeletal muscle extends the capacity to activate satellite cell proliferation (Charkravarthy, et al., 2000), increasing and prolonging the beneficial effects to the aging muscle.