Microbial shifts in the aging mouse gut

Abstract

BackgroundThe changes that occur in the microbiome of aging individuals are unclear, especially in light of the imperfect correlation of frailty with age. Studies in older human subjects have reported subtle effects, but these results may be confounded by other variables that often change with age such as diet and place of residence. To test these associations in a more controlled model system, we examined the relationship between age, frailty, and the gut microbiome of female C57BL/6 J mice.ResultsThe frailty index, which is based on the evaluation of 31 clinical signs of deterioration in mice, showed a near-perfect correlation with age. We observed a statistically significant relationship between age and the taxonomic composition of the corresponding microbiome. Consistent with previous human studies, the Rikenellaceae family, which includes the Alistipes genus, was the most significantly overrepresented taxon within middle-aged and older mice.The functional profile of the mouse gut microbiome also varied with host age and frailty. Bacterial-encoded functions that were underrepresented in older mice included cobalamin (B12) and biotin (B7) biosynthesis, and bacterial SOS genes associated with DNA repair. Conversely, creatine degradation, associated with muscle wasting, was overrepresented within the gut microbiomes of the older mice, as were bacterial-encoded β-glucuronidases, which can influence drug-induced epithelial cell toxicity. Older mice also showed an overabundance of monosaccharide utilization genes relative to di-, oligo-, and polysaccharide utilization genes, which may have a substantial impact on gut homeostasis.ConclusionWe have identified taxonomic and functional patterns that correlate with age and frailty in the mouse microbiome. Differences in functions related to host nutrition and drug pharmacology vary in an age-dependent manner, suggesting that the availability and timing of essential functions may differ significantly with age and frailty. Future work with larger cohorts of mice will aim to separate the effects of age and frailty, and other factors.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-014-0050-9) contains supplementary material, which is available to authorized users.

Involvement of a gut–retina axis in protection against dietary glycemia-induced age-related macular degeneration

“…5A and Fig. S8 B and C) (45,46). At T2 (21 mo of age), the microbiome of HGxoLG mice was distinct from that of HG mice and started to resemble LG microbiomes (Fig.…”

The aging immune system and nutritional interventions

“…Importantly, the mucin-degrading bacterium Akkermansia muciniphila was shown to reverse these metabolic disorders by strengthening the intestinal barrier [589]. In our study old conventional mice had lower abundance of Akkermansia, which has also been reported previously both in humans and mice [590,591]. Akkermansia was also less abundant after transfer of old microbiota to germ-free mice at early time points.…”

Cecal microbiota association with tumor load in a colorectal cancer mouse model

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