Extended Data Figure 6: Signs of sarcopenia in muscle biopsies of geriatric individuals, and impaired myogenesis and increased senescence of human geriatric satellite cells.

a, Representative images of haematoxylin and eosin (H/E) staining in cryosections of muscles from human donors at different ages: adult (30 years), old (65 years) and geriatric (96 years). Asterisks indicate atrophic myofibres. Arrow indicates a central nucleated myofibre. b, CD56, p16^INK4a and Igfbp5 immunostaining in muscle biopsies of geriatric (83 ± 7 years) and adult (28 ± 7 years) individuals. Scale bars, 25 μm. c, Percentage of BrdU incorporation after 1 h pulse in adult and geriatric human satellite cells in proliferation conditions (growth medium). Representative pictures of BrdU immunostaining are shown. d, Representative pictures of eMHC immunostaining of adult and geriatric human satellite cells after culturing for 48 h in differentiation conditions (differentiation medium). The percentage of nuclei inside the myotubes was quantified to determine fusion capacity. Scale bars, 50 μm. Data are mean ± s.e.m. Two-sided Mann–Whitney U-test was used to assess statistical significance. P values are indicated. a, b, Representative pictures from n = 8 for adult, n = 5 for old, and n = 10 for geriatric human donors; c, d, n = 5 biological replicates. n.s., not significant.