Skeletal muscle regeneration and the mitotic clock

Regeneration of muscle fibers following damage requires activation of quies cent satellite cells, their proliferation and finally their differentiation and fusion into multinucleated myotubes, which after maturation will repla ce the damaged fiber. The regenerative potential of human skeletal muscle w ill be determined, at least partly, by the proliferative capacity of the sa tellite cells. In this study, we have measured the proliferative life span of human satellite cells until they reach senescence. These analyses were p erformed on cell populations isolated from old and young donors as well as from one child suffering from Duchenne muscular dystrophy, where extensive regeneration had occurred. In order to see if there are any age-related cha nges in the myogenic program we have also compared the program of myogenic differentiation expressed by satellite cells from these subjects at differe nt stages of their proliferative lifespan. (C) 2000 Elsevier Science Inc. A ll rights reserved.