Sex differences in the associations between L-arginine pathway metabolites, skeletal muscle mass and function, and their responses to resistance exercise, in old age

Da Boit, M. et al. (2018) Sex differences in the associations between L-arginine pathway metabolites, skeletal muscle mass and function, and their responses to resistance exercise, in old age. Journal of Nutrition, Health and Aging, 22(4), pp. 534-540. (doi: 10.1007/s12603-017-0964-6)

Abstract

Objectives The current study was designed to explore the associations between L-arginine metabolites and muscle mass and function in old age, which are largely unknown. Design: The study used a randomised, double-blind, placebo-controlled design. Setting: The study was carried out in a laboratory setting. Participants: 50 healthy older adults [median age 70 years (IQR 67-73); 27 males]. Intervention: Participants undertook an 18-week resistance exercise program, and a nutritional intervention (fish oil vs. placebo). Measurements: Serum homoarginine, ornithine, citrulline, asymmetric dimethylarginine (ADMA), NG-monomethyl-L-arginine (L-NMMA), and symmetric dimethylarginine (SDMA), maximal voluntary contraction (MVC) and isokinetic torque of the knee extensors at 30° s-1 (MIT), muscle cross sectional area (MCSA) and quality (MQ) were measured at baseline and after the intervention. Results: No significant exercise-induced changes were observed in metabolite concentrations. There were significant sex differences in the associations between metabolites and muscle parameters. After adjusting for age, glomerular filtration rate and fish oil intervention, citrulline (P=0.002) and ornithine (P=0.022) were negatively associated with MCSA at baseline in males but not females. However, baseline citrulline was negatively correlated with exercise-induced changes in MVC (P=0.043) and MQ (P=0.026) amongst females. Furthermore, amongst males, baseline homoarginine was positively associated with exercise-induced changes in MVC (P=0.026), ADMA was negatively associated with changes in MIT (P=0.026), L-NMMA (p=0.048) and ornithine (P<0.001) were both positively associated with changes in MCSA, and ornithine was negatively associated with changes in MQ (P=0.039). Conclusion: Therefore, barring citrulline, there are significant sex differences in the associations between L-arginine metabolites and muscle mass and function in healthy older adults. These metabolites might enhance sarcopenia risk stratification, and the success of exercise programs, in old age.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Elliott, Professor David and Gray, Professor Stuart
• Authors: Da Boit, M., Tommasi, S., Elliott, D., Zinellu, A., Sotgia, S., Sibson, R., Meakin, J.R., Aspden, R.M., Carru, C., Mangoni, A.A., and Gray, S.R.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences; College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: Journal of Nutrition, Health and Aging
• Publisher: Springer
• ISSN: 1279-7707
• ISSN (Online): 1760-4788
• Published Online: 02 September 2017
• Copyright Holders: Copyright © 2017 Serdi and Springer-Verlag International SAS, part of Springer Nature
• First Published: First published in Journal of Nutrition, Health and Aging 22(4):534-540
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher