1. Morphological changes in skeletal muscles during aging in mammals.
Morphological changes in skeletal muscles during aging in mammals. Muscle aging is characterized in mammals by a decline in the regenerative capacity, caused by a reduction in the number and function of muscle satellite cells (shown in blue). A decrease in the overall muscle strength and mass due to a decrease in the number and size of type IIb fibers (pink) and, to a lesser extent, type I fibers (red), is accompanied by defects in neuromuscular junctions and innervation (black). As the muscle ages, cycles of denervation and re-innervation eventually lead to changes in fiber-type composition, with a proportional increase in type I fibers (red), and grouping (stacking of red fibers). An accumulation of interstitial adipocytes (yellow) and decreased capillarization (not shown) are also observed. In Drosophila, defects in neuromuscular junctions have been described but there is currently no evidence for the presence of age-related changes in muscle mass that are seen in mammals.
Fabio Demontis et al. Dis. Model. Mech. 2013;6:
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