|Lustgarten, Michael - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
|Price, Lori Lyn - Tufts - New England Medical Center|
|Fielding, Roger - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
Submitted to: Medicine and Science in Sports and Exercise
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2014
Publication Date: 8/1/2015
Citation: Lustgarten, M., Price, L., Fielding, R.A. 2015. Analytes and metabolites associated with muscle quality in young, healthy adults. Medicine and Science in Sports and Exercise. 47(8):1659-1664. doi: 10.1249/mss.0000000000000578.
Interpretive Summary: Identification of mechanisms that underlie lower extremity muscle quality (leg press one repetition maximum/total lean mass; LP/Lean) may be important for individuals interested in optimizing fitness and sport performance. The purpose of the current study was to characterize the association between 303 circulating metabolites and analytes with LP/Lean in young, healthy adults. Metabolites or analytes related to dietary protein intake, excitation contraction coupling, gut bacterial metabolism and peroxisome proliferator activated receptor alpha (PPAR a) activation were associated with LP/Lean. Future studies aimed at investigating the causative role of these pathways on lower extremity muscle quality are of interest.
Technical Abstract: Purpose: Identification of mechanisms that underlie lower extremity muscle quality (leg press one repetition maximum/total lean mass; LP/Lean) may be important for individuals interested in optimizing fitness and sport performance. The purpose of the current study was to provide observational insight into mechanisms that may underlie muscle quality by characterizing the association between 286 mass spectrometry metabolites and 17 chemistry screen analytes with LP/Lean in young, healthy adults (N = 77 (49 women and 28 men); mean age, 24.4 +/- 4.2 yr; BMI, 23.5 +/- 2.6 kgIm(-2)). Methods: Principal components analysis (PCA) was used to reduce the 286 metabolites into 73 metabolite-containing PCA factors. Sex-adjusted linear regression was used to examine the association between PCA factors and chemistry screen analytes with LP/Lean. Q values were computed to account for multiple comparison testing. Stepwise linear regression and leave-one-out cross validation were used to identify a predictor set representative of LP/Lean and to assess internal validity, respectively. Results: Metabolites or analytes related to dietary protein intake (albumin, branched-chain amino acids (BCAA)) and excitation-contraction coupling (calcium and magnesium) were positively associated, whereas metabolites related to gut bacterial metabolism (cinnamoylglycine, hydrocinnamate, hippurate, indolepropionate) and peroxisome proliferator–activated receptor-alpha (PPAR-alpha) (methylglutarylcarnitine and cinnamoylglycine) activation were negatively associated with LP/Lean. Use of leave-one-out cross validation identified magnesium, sex, and the PCA factors containing BCAAs and methionine and methylglutarylcarnitine to be present in more than 90% of the stepwise regression models, thereby explaining 26.7% of the variance (adjusted R(2)) inherent in muscle quality. Conclusion: Collectively, these data suggest that mechanisms related to dietary protein intake, excitation-contraction coupling, gut microbial metabolism, and PPAR-alpha activation may underlie lower extremity muscle quality in young, healthy adults.