Fecal Microbiota Transplant From Young Mice Improves Muscle and Skin in Old Mice

The gut microbiome changes with age, the balance of microbial populations shifting in ways that contribute to degenerative aging. There are more inflammatory microbes, more microbes generating harmful metabolites, and fewer microbes generating beneficial metabolites. One of the ways to address this issue is to transplant fecal matter from a young individual into the gut of the older individual. The result is a lasting improvement in the gut microbiome, and consequent improvement in health. Here, researchers look specifically at muscle and skin function in aged mice following fecal microbiota transplant from young mice, and find improvements.

Aging is a natural process that an organism gradually loses its physical fitness and functionality. Great efforts have been made to understand and intervene in this deteriorating process. The gut microbiota affects host physiology, and dysbiosis of the microbial community often underlies the pathogenesis of host disorders. The commensal microbiota also changes with aging; however, the interplay between the microbiota and host aging remains largely unexplored. Here, we systematically examined the ameliorating effects of the gut microbiota derived from the young on the physiology and phenotypes of the aged.

As the fecal microbiota was transplanted from young mice at 5 weeks after birth into 12-month-old ones, the thickness of the muscle fiber and grip strength were increased, and the water retention ability of the skin was enhanced with thickened stratum corneum. Muscle thickness was also marginally increased in 25-month-old mice after transferring the gut microbiota from the young. Bacteria enriched in 12-month-old mice that received the young-derived microbiota significantly correlated with the improved host fitness and altered gene expression. In the dermis of these mice, transcription of Dbn1 was most upregulated and DBN1-expressing cells increased twice.

We revealed that the young-derived gut microbiota rejuvenates the physical fitness of the aged by altering the microbial composition of the gut and gene expression in muscle and skin. Dbn1, for the first time, was found to be induced by the young microbiota and to modulate skin hydration. Our results provide solid evidence that the gut microbiota from the young improves the vitality of the aged.

Link: https://doi.org/10.1186/s40168-022-01386-w