Figure 1.

OPA1 Expression Is Reduced during Aging in Sarcopenic Patients

(A) Mitochondria-shaping machinery is downregulated in sarcopenia and maintained by lifelong exercise. Quantitative PCR analysis of mitochondrial dynamics transcripts from human muscle biopsies of 5 young subjects, 7 sedentary seniors, and 11 senior sportsmen is shown. Data represent mean ± SEM and are normalized for GAPDH.

(B) Densitometric analysis of OPA1/Complex II, MFN1/Complex II, and DRP1/Complex II signal ratios revealed by immunoblotting. Data represent mean ± SEM of four independent experiments (young = 5, sedentary seniors = 19, senior sportsmen = 5).

(C) Linear regression analysis including OPA1, DRP1, and MFN1 expression levels and myofiber size in elderly persons (n = 24). Red spots depict senior sportsmen.

(D) Linear regression showing that decrease of OPA1 but not of DRP1 or MFN1 levels correlates with muscle weakness in elderly persons (n = 24). Red spots depict senior sportsmen.

(E) Representative immunoblot and densitometric analysis of OPA1 in homogenates of tibialis anterior muscles from young (6 months old, n = 6), old (18 months old, n = 9) and old trained mice (18 months old, n = 6). Data are expressed as mean ± SEM; ^∗p ≤ 0.05, ^∗∗p < 0.01.