Aged skeletal muscle undergoes metabolic and structural alterations eventually resulting in a loss of muscle strength and mass, i.e. age-related sarcopenia. Therefore, novel targets for muscle growth purposes in elderly are needed. Here, we explored the role of the cannabinoid system in muscle plasticity through the expression of muscle cannabinoid receptors (CBs) in young and old humans. The CB1 expression was higher (+ 25%; p = 0.04) in muscle of old (≥ 65 years) vs. young adults (20-27 years), whereas CB2 was not differently expressed. Furthermore, resistance exercise tended to increase the CB1 (+ 11%; p = 0.055) and CB2 (+ 37%; p = 0.066) expression in muscle of older adults. Interestingly, increases in the expression of CB2 following resistance exercise positively correlated with changes in key mechanisms of muscle homeostasis, such as catabolism (FOXO3a) and regenerative capacity (Pax7, MyoD). This study for the first time shows that CB1 is differentially expressed with aging and that changes in CB2 expression upon resistance exercise training correlate with changes in mediators that play a central role in muscle plasticity. These data confirm earlier work in cells and mice showing that the cannabinoid system might orchestrate muscle growth, which is an incentive to further explore CB-based strategies that might counteract sarcopenia.
© 2021. The Author(s).
- Cruz-Jentoft, A. J. et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing 48, 16–31 (2019). – DOI
- Liao, C. D., Chen, H. C., Huang, S. W. & Liou, T. H. The role of muscle mass gain following protein supplementation plus exercise therapy in older adults with sarcopenia and frailty risks: A systematic review and meta-regression analysis of randomized trials. Nutrients 11, 1713 (2019). – DOI
- Dalle, S. et al. Omega-3 supplementation improves isometric strength but not muscle anabolic and catabolic signaling in response to resistance exercise in healthy older adults. J. Gerontol. A Biol. Sci. Med. Sci. 76, 406–414 (2021). – DOI
- Dupont, J., Dedeyne, L., Dalle, S., Koppo, K. & Gielen, E. The role of omega-3 in the prevention and treatment of sarcopenia. Aging Clin. Exp. Res. 31, 825–836 (2019). – DOI
- Antoniak, A. E. & Greig, C. A. The effect of combined resistance exercise training and Vitamin D 3 supplementation on musculoskeletal health and function in older adults: A systematic review and meta-analysis. BMJ Open 7, e014619 (2017). – DOI