Effects of a nutritional supplement in older individuals subject to ten days of complete bed rest.

Older individuals subjected to complete bed rest for 10 days were randomized to a complete nutritional supplement with or without hydroxymethyl butyrate (HMB). Muscle biopsies from the vastus lateralis were obtained immediately prior and at the conclusion of the bed rest. RNA-sequencing was performed to determine the gene expression changes associated with bed rest. Marked decrease in the expression of genes associated with mitochondrial energy metabolism including fatty acid oxidation, TCA cycle and the electron transport chain was observed with bed rest. These effects were partly mitigated in the subjects provided the nutritional supplement with HMB. RNA-sequencing was performed on 5 individual subjects in both the placebo and HMB groups before and after 10 days of complete bed rest.