Dataset for: Post-exercise essential amino acid supplementation amplifies skeletal muscle satellite cell proliferation in older men 24 hours post-exercise

Aged skeletal muscle has an attenuated and delayed ability to proliferate satellite cells in response to resistance exercise. The mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway is a focal point for cell growth, however the effect of post-exercise mTORC1 activation on human skeletal muscle satellite cell (SC) proliferation is unknown. To test the proliferative capacity of skeletal muscle SC in aging muscle to a potent mTORC1 activator (i.e., EAA; essential amino acids) we recruited older (~72y) men to conduct leg resistance exercise (8sets x10reps) without (-EAA;n=8) and with (+EAA:n=11) ingestion of 10g of EAA 1h post exercise. Muscle biopsies were taken before exercise (Pre) and 24h post-exercise (Post) for assessment of expression and fiber type-specific Pax7+ SC, Ki67+Pax7+ SC and MyoD+ SC. -EAA did not show an increase in Pax7+ satellite cells at Post (p>0.82). Although statistical significance for an increase in Pax7+ SC at 24 h post-RE was not observed in +EAA vs –EAA, we observed trends for a treatment difference (p<0.1). When examining the change from Pre to Post trends were demonstrated (#/myofiber:p=0.076; and %/ myonuclei:p=0.065) for a greater increase in +EAA vs –EAA. Notably, we found an increases SC proliferation in +EAA, but not -EAA with increases in Ki67+ SC and MyoD+ cells (p<0.05). Ki67+ SC also exhibited a significant group difference Post (p<0.010). Pax7+ SC in fast twitch myofibers did not change and was not different between groups (p>0.10). CDK2, MEF2C, RB1 mRNA only increased in +EAA (p<0.05). Acute muscle satellite cell proliferative capacity may be partially rescued with post-exercise EAA ingestion in older men.

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