Renormalized basal metabolic rate describes the human aging process and longevity

Area of Science:

• Gerontology
• Metabolic Science
• Biomarker Discovery

Background:

• Aging and mortality are central to life sciences, yet existing biomarkers lack predictive power for longevity.
• Current aging theories propose biomarkers, but their efficacy in predicting lifespan and aging trajectory remains limited.

Purpose of the Study:

• To introduce a novel biomarker for human aging based on mass-specific basal metabolic rate (msBMR).
• To validate the predictive capability of this new biomarker for mortality and survival rates.

Main Methods:

• Renormalized the mass-specific basal metabolic rate (msBMR) by incorporating body mass index, creating the renormalized msBMR (RmsBMR).
• Validated the RmsBMR using large cohorts of American, Italian, and Japanese men, analyzing mortality rates and survival curves.
• Observed mitochondrial number decay in mice, correlating it with RmsBMR decline.

Main Results:

• The RmsBMR demonstrated strong predictive power for mortality and survival rates across American, Italian, and Japanese populations.
• A plateau in mortality rates among centenarians corresponded to the lowest RmsBMR threshold, indicating the final life stage.
• RmsBMR decline with age was linked to mitochondrial decay, potentially due to fusion/fission system fluctuations.

Conclusions:

• The RmsBMR is a robust biomarker for human aging, outperforming existing measures in predicting longevity.
• The study links metabolic rate decline to aging-related mitochondrial decay, providing a mechanistic explanation.
• This approach elucidates the regulation of basal metabolic rate in mammals via algometric scaling laws.