Ageing is thought to participate to the pathogenesis of sporadic inclusion-body myositis (s-
IBM). Although the regenerative potential of s-IBM muscle is reduced in vivo, age-related
abnormalities of satellite cells possibly accounting for the decline of muscle repair have not
been demonstrated. Here we show that proliferation rate and clonogenicity of s-IBM
myoblasts are significantly lower and doubling time is longer than normal age-matched
controls, indicating that proliferative capacity of s-IBM muscles becomes exhausted earlier …