Upregulation of colonic luminal polyamines produced by intestinal microbiota delays senescence in mice.

Prevention of quality of life (QOL) deterioration is associated with the inhibition of geriatric diseases and the regulation of brain function. However, no substance is known that prevents the aging of both body and brain. It is known that polyamine concentrations in somatic tissues (including the brain) decrease with increasing age, and polyamine-rich foods enhance longevity in yeast, worms, flies, and mice, and protect flies from age-induced memory impairment. A main source of exogenous polyamines is the intestinal lumen, where they are produced by intestinal bacteria. We found that arginine intake increased the concentration of putrescine in the colon and increased levels of spermidine and spermine in the blood. Mice orally administered with arginine in combination with the probiotic bifidobacteria LKM512 long-term showed suppressed inflammation, improved longevity, and protection from age-induced memory impairment. This study shows that intake of arginine and LKM512 may prevent aging-dependent declines in QOL via the upregulation of polyamines.

Cerebral low-molecular metabolites influenced by intestinal microbiota: a pilot study.

Recent studies suggest that intestinal microbiota influences gut-brain communication. In this study, we aimed to clarify the influence of intestinal microbiota on cerebral metabolism. We analyzed the cerebral metabolome of germ-free (GF) mice and Ex-GF mice, which were inoculated with suspension of feces obtained from specific pathogen-free mice, using capillary electrophoresis with time-of-flight mass spectrometry (CE-TOFMS). CE-TOFMS identified 196 metabolites from the cerebral metabolome in both GF and Ex-GF mice. The concentrations of 38 metabolites differed significantly (p < 0.05) between GF and Ex-GF mice. Approximately 10 of these metabolites are known to be involved in brain function, whilst the functions of the remainder are unclear. Furthermore, we observed a novel association between cerebral glycolytic metabolism and intestinal microbiota. Our work shows that cerebral metabolites are influenced by normal intestinal microbiota through the microbiota-gut-brain axis, and indicates that normal intestinal microbiota closely connected with brain health and disease, development, attenuation, learning, memory, and behavior.

Impact of intestinal microbiota on intestinal luminal metabolome.

Low-molecular-weight metabolites produced by intestinal microbiota play a direct role in health and disease. In this study, we analyzed the colonic luminal metabolome using capillary electrophoresis mass spectrometry with time-of-flight (CE-TOFMS) -a novel technique for analyzing and differentially displaying metabolic profiles- in order to clarify the metabolite profiles in the intestinal lumen. CE-TOFMS identified 179 metabolites from the colonic luminal metabolome and 48 metabolites were present in significantly higher concentrations and/or incidence in the germ-free (GF) mice than in the Ex-GF mice (p < 0.05), 77 metabolites were present in significantly lower concentrations and/or incidence in the GF mice than in the Ex-GF mice (p < 0.05), and 56 metabolites showed no differences in the concentration or incidence between GF and Ex-GF mice. These indicate that intestinal microbiota highly influenced the colonic luminal metabolome and a comprehensive understanding of intestinal luminal metabolome is critical for clarifying host-intestinal bacterial interactions.