Leucine supplementation attenuates the loss of skeletal muscle mass and function in older adults during bed rest. We sought to determine whether leucine could also preserve and/or restore mitochondrial function and muscle oxidative capacity during periods of disuse and rehabilitation. Healthy, older adults (69.1 ± 1.1 yr) consumed a structured diet with supplemental leucine (LEU: 0.06 g/kg body weight/meal; n = 8) or alanine (CON: 0.06 g/kg body weight/meal; n = 8) during 7 days of bed rest and 5 days of inpatient rehabilitation. A 75-g oral glucose tolerance test (OGTT) was performed at baseline (PreBR), after bed rest (PostBR), and rehabilitation (PostRehab) and used to calculate an indicator of insulin sensitivity and metabolic clearance rate (MCR). Tissue samples from the m. vastus lateralis were collected at PreBR, PostBR, and PostRehab to assess mitochondrial respiratory capacity and protein markers of the oxidative phosphorylation and a marker of the antioxidant defense systems. During bed rest, leucine tended to preserve insulin sensitivity (change in MCR, CON vs. LEU:-3.5 ± 0.82 vs. LEU: 0.98 ± 0.88, P = 0.054), but had no effect on mitochondrial respiratory capacity (change in state 3þsuccinate CON vs. LEU 8.7 ± 6.1 vs. 7.3 ± 4.1 pmol O2/s/mg tissue, P = 0.10). Following rehabilitation, leucine increased ATP-linked respiration (CON vs. LEU:-8.9 ± 6.2 vs. 15.5 ± 4.4 pmol O2/s/mg tissue, P = 0.0042). Although the expression of mitochondrial respiratory and antioxidant proteins was not impacted, leucine supplementation preserved specific pathways of mitochondrial respiration, insulin sensitivity, and a marker of oxidative stress during bed rest and rehabilitation.
|Number of pages||12|
|Journal||Journal of Applied Physiology|
|State||Published - May 2021|
Bibliographical noteFunding Information:
The study was supported by Nursing Research at the National Institutes of Health (R01 NR012973 to D.P-J) and in part by the Claude D. Pepper Older Americans Independence Center grant (P30 AG024832) and the National Center for Research Resources (1UL1RR029876). This study was conducted with the support of UTMB’s Institute for Translational Sciences, supported by Clinical and Translational Science Awards (UL1TR000071 and UL1TR001439) from the National Center for Advancing Translational Sciences.
Copyright © 2021 the American Physiological Society.
- Bed rest
- Dietary supplementation
ASJC Scopus subject areas
- Physiology (medical)