Effects of essential amino acid supplementation on muscle structure before and after eccentric exercise

(In-Person) Poster Presentation 

We have recently shown in older adults that daily ingestion of essential amino acids (EAAs) for seven consecutive days can increase muscle stem cells (satellite cells). We want to see if we can measure a similar increase in satellite cells in younger adults. Satellite cells are important for muscle maintenance and repair. One way to stimulate muscle repair is to perform eccentric-type contractions (muscle lengthens and is damaged under tension). As such, we gave subjects EAA or placebo 3x/ day for 7 days before and after a single bout of damaging exercise to test the following hypotheses compared to placebo: 1) EAAs for 7 days will increase satellite cell numbers, 2) cause more satellite cells to be activated/proliferate 24 hours after damaging exercise, and 3) lead to more robust repair (less damage) 7 days after damaging exercise (14 days after EAAs began). Tissue samples from eight subjects have been processed. Additional subjects are in various stages of recruitment/consenting. Immunohistochemical methods will be used to measure muscle satellite cell and myonuclei numbers associated with type I, IIa and IIx fibers, satellite cell distance to nearest capillaries, and muscle fiber denervation and immune cell responses. Our overarching objective is to devise ways to boost resilience of muscle tissues in active and inactive young and older adults.