Primary human muscle precursor cells obtained from young and old donors produce similar proliferative, differentiation and senescent profiles in culture

The myogenic behaviour of primary human muscle precursor cells (MPCs) obtained from young (aged 2025years) and elderly people (aged 6782years) was studied in culture. Cells were compared in terms of proliferation, DNA damage, time course and extent of myogenic marker expression during differentiation, fusion, size of the formed myotubes, secretion of the myogenic regulatory cytokine TGF-1 and sensitivity to TGF-1 treatment. No differences were observed between cells obtained from the young and elderly people. The cell populations were expanded in culture until replicative senescence. Cultures that maintained their initial proportion of myogenic cells (desmin positive) with passaging (n=5) were studied and compared with cells from the same individuals in the non-senescent state. The senescent cells exhibited a greater number of cells with DNA damage (-H2AX positive), showed impaired expression of markers of differentiation, fused less well, formed smaller myotubes and secreted more TGF-. The data strongly suggest that MPCs from young and elderly people have similar myogenic behaviour.