Low molecular weight metabolites produced by the intestinal microbiome that have been associated with health and disease as metabolites need to be constantly absorbed from the intestinal lumen and transported to intestinal epithelial cells and blood. Polyamines, especially spermidine and spermine, are bioactive chemicals which promote autophagy and suppress inflammation. The main source of exogenous polyamines is the intestinal lumen, where they are produced by intestinal microbiome. Considering the intestinal microbiome as a manufacturing plant for bioactive substances, we developed a novel hybrid putrescine biosynthesis system strategy, in which the simultaneous intake of Bifidobacterium animalis ssp. lactis LKM512 (Bifal) and arginine (Arg) upregulates the production of the putrescine, a precursor of spermidine and spermine, in the gut by controlling the bacterial metabolism beyond its vast diversity and inter-individual differences. In a clinical trial, healthy individuals with a body mass index near the maximum "healthy" range (25 kg/m3; n = 44) were randomized to consume either normal yogurt containing Bifal and Arg (Bifal + Arg YG) or placebo (normal yogurt) for 12 weeks. The change in reactive hyperemia index determined by EndoPAT from week 0 to 12 in the Bifal + Arg YG group was significantly higher than that in the placebo group, indicating that Bifal + Arg YG intake improved vascular endothelial function. In addition, the concentrations of fecal putrescine and serum spermidine in the Bifal+ Arg YG group were significantly higher than those in the placebo group. These findings suggest that consuming Bifal + Arg YG prevents or reduces atherosclerosis risk by upregulating blood spermidine levels, which subsequently induces autophagy.
Keywords: Bifidobacterium animalis subsp. lactis; arginine; atherosclerosis; intestinal microbiome; metabolomics; polyamine.