Skeletal muscle proteomics links mitochondrial abundance with peak fat oxidation in physically active young males.
Level 4 - case-series / case-control
Cross-sectional physiological study evaluating correlational associations in humans.
PubMed 42210546 · doi:10.1113/JP290966
What was done
Thirty-four young, lean, physically active males underwent phenotyping including aerobic capacity (VO2peak), peak fat oxidation (PFO), the exercise intensity at peak fat oxidation (Fat max), body composition, fasting blood samples, and a skeletal muscle biopsy. Liquid chromatography-mass spectrometry (LC-MS) based untargeted proteomics was performed to quantify skeletal muscle protein abundance and analyze its association with fat oxidation metrics.
What was found
Absolute PFO was positively correlated with VO2peak (r = 0.496, P = 0.003). Relative PFO and Fat max were positively associated with mitochondrial proteome abundance (r = 0.633, P < 0.001 and r = 0.595, P < 0.001, respectively), with complex V specifically associated with both metrics. Multiple regression showed that mitochondrial abundance and muscle glycogen explained 55% of the variance in relative PFO, mitochondrial abundance alone explained 43% of the variance in Fat max, and absolute PFO was explained by a combination of VO2peak, mitochondrial abundance, and muscle glycogen (r^2 = 0.562).
Why it matters
It identifies specific skeletal muscle proteomic features, particularly mitochondrial abundance and respiratory complex V, as key biological determinants explaining interindividual variability in peak fat oxidation capacity during exercise.
Limits
The study is cross-sectional and observational, preventing causal inference. The sample size is modest (n = 34) and restricted entirely to young, lean, active males, limiting generalizability to females, older adults, or sedentary/clinical populations.
Cited by
- supports Mitochondrial content largely limits or determines fat oxidation in skeletal muscle during exercise.