OxPhos defects cause hypermetabolism and reduce lifespan in cells and in patients with mitochondrial diseases.
Level 3 - non-randomized controlled study
Multi-cohort observational data synthesis (17 cohorts) paired with in vitro laboratory mechanistic investigations
PubMed 36635485 · doi:10.1038/s42003-022-04303-x
What was done
The authors integrated data from 17 clinical cohorts of patients with primary mitochondrial oxidative phosphorylation (OxPhos) defects (total n = 690) to evaluate resting energy expenditure. They also longitudinally characterized patient-derived human fibroblasts subjected to genetic or pharmacological OxPhos disruption, assessing cellular energy expenditure, OxPhos coupling efficiency, mitochondrial DNA stability, integrated stress response activation, secretome alterations (including GDF15), telomere erosion, epigenetic aging, and longitudinal RNA sequencing and DNA methylation profiles.
What was found
OxPhos defects increased resting energy expenditure (hypermetabolism) in patients across the 17 cohorts. In patient-derived fibroblasts, genetic or pharmacological disruption of OxPhos approximately doubled cellular energy expenditure while maintaining near-normal coupling efficiency. Hypermetabolism was linked to mtDNA instability, integrated stress response activation, increased secretion of GDF15 and other age-related cytokines/metabokines, and accelerated telomere erosion and epigenetic aging per cell division. Specific numerical effect sizes, confidence intervals, and p-values were not reported in the abstract.
Why it matters
The findings indicate that primary OxPhos deficiencies increase the basal energetic cost of living (hypermetabolism), suggesting an energetic mechanism linking mitochondrial dysfunction to accelerated biological aging.
Limits
The abstract omits quantitative effect sizes, variance estimates, and p-values for both the clinical meta-cohort and the in vitro experiments. The clinical evidence relies on pooled observational cohort data, and mechanistic links between hypermetabolism, telomere erosion, and epigenetic aging were demonstrated in cell culture rather than directly in longitudinal patient outcomes.
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