Age-Related Colonic Mucosal Microbiome Community Shifts in Monkeys.

Aging-related changes in gut microbiome changes impacts host health. The interactive relationship between the microbiome and physiological systems in an aged body system remains to be clearly defined, particularly in the context of inflammation. Therefore, we aimed to evaluate systemic inflammation, microbial translocation (MT) and differences between fecal and mucosal microbiomes. Ascending colon mucosal biopsies, fecal and blood samples from healthy young and old female vervet monkeys were collected for 16S rRNA gene sequencing, MT and cytokine analyses, respectively. To demonstrate microbial co-occurrence patterns, we used Kendall's tau correlation measure of interactions between microbes. We found elevated levels of plasma LBP-1, MCP-1 and CRP in old monkeys, indicative of higher MT and systemic inflammation. Microbiome analysis revealed significant differences specific to age. At the phylum level, abundances of pathobionts such as Proteobacteria were increased in the mucosa of old monkeys. At the family level, Helicobacteriaceae was highly abundant in mucosal samples (old); in contrast, Ruminococcaceae were higher in fecal samples old monkeys. We found significantly lower Firmicutes:Bacteroidetes ratio and lower abundance of butyrate-producing microbes in old monkeys, consistent with less healthy profiles. Microbial community co-occurrence analysis on mucosal samples revealed 13 nodes and 41 associations in the young monkeys, but only 12 nodes and 21 associations in the old monkeys. Our findings provided novel insights into systemic inflammation and gut microbial interactions, highlights the importance of the mucosal niche, and facilitates further understanding of the decline in the stability of the microbial community with aging.