Augmented temperature fluctuation aggravates muscular atrophy through the gut microbiota

Area of Science:

• Environmental Health
• Gerontology
• Microbiology

Background:

• Large temperature differences pose health risks.
• Sarcopenia, characterized by muscle loss, is a common age-related condition.
• The impact of temperature fluctuations on sarcopenia remains understudied.

Purpose of the Study:

• To investigate the correlation between diurnal temperature range and sarcopenia prevalence in humans.
• To explore the effects of fluctuated temperature exposure on muscle function and gut microbiota in mice.
• To elucidate the underlying mechanisms linking temperature fluctuation, microbiota alterations, and muscle dysfunction.

Main Methods:

• Correlation analysis between diurnal temperature range and sarcopenia prevalence.
• Experimental exposure of mid-aged male mice to fluctuated temperatures (10-25°C).
• 16S rRNA sequencing to analyze gut microbiota composition.
• Microbiota transplantation experiments and in vitro assays to assess mitochondrial function and mitophagy.

Main Results:

• A positive correlation was observed between higher diurnal temperature range and increased sarcopenia prevalence.
• Fluctuated temperature exposure accelerated muscle atrophy and reduced exercise performance in mice.
• Significant alterations in gut microbiota composition were identified, including increased Parabacteroides distasonis and Duncaniella dubosii, and decreased Candidatus Amulumruptor, Roseburia, and Eubacterium.
• Transplantation of microbiota from fluctuated temperature-exposed mice replicated adverse muscle effects.
• Altered microbiota led to increased circulating aminoadipic acid, which impaired mitochondrial function by inhibiting mitophagy.
• Eubacterium supplementation mitigated muscle atrophy and dysfunction.

Conclusions:

• Fluctuated temperatures detrimentally impact muscle function and performance.
• Gut microbiota alterations play a crucial role in mediating the adverse effects of temperature fluctuation on muscle health.
• Increased aminoadipic acid resulting from microbiota changes contributes to mitochondrial dysfunction and muscle atrophy.
• Targeting the gut microbiota, specifically with Eubacterium, offers a potential therapeutic strategy for temperature-induced muscle dysfunction.