In elderly muscle MGF treatment activates “resting” cells to proliferate and fuse to donate nuclei. Cultures from neonatal, young adult, and old adult muscle were treated with the unique MGF peptide (MGF E) 24aa at a concentration of 100 ng/mL at day 0 or day 3 of differentiation. Immunofluorescence was performed on cultures with an antibody directed against Desmin (a marker of progenitor cell status). In elderly muscle there are still some muscle satellite/stem cells in a quiescent state but these are not normally activated because older muscle does not normally produce much MGF. However when the unique E peptide of the MGF was added to cultures from elderly muscle these cells replicated. The prospects of “awakening” of these resting progenitor cells appear to offer a means of enhancing muscle maintenance and repair in the elderly offers and in certain diseases such as muscular dystrophy and ALS (Kandalla et al. [29]).
