The impact of gut microbiota on vascularization of the small intestine

Abstract

The commensal microbiota resides in a mutualistic relationship within the mammalian gut. It significantly influences the formation of capillary networks in the small intestine, not only during development but also in adulthood. Mucosal capillaries in small intestinal villus structures play a critical role for the uptake of dietary nutrients and immune regulation. Emerging studies have elucidated how the composition of gut microbiota can influence not only postnatal gut development regarding immune tolerance, nutrient absorption, and morphology but also the development and maintenance of blood and lymphatic capillaries within the small intestine. In particular, the analysis of gnotobiotic mouse models affirmed the importance of the gut microbiota, or even only single gut bacteria, in the remodeling of the small intestinal capillaries. Here, different epithelial-to-endothelial cross talk pathways, e.g. Paneth cell-derived signals, Toll-like receptor signaling, or tissue factor–protease activated receptor-1 signaling, have been reported to affect intestinal villus vascular remodeling in a microbiota-dependent fashion. In this review article, we will provide a comprehensive overview on the relevant microbiota–host interaction pathways, which have been revealed to influence angiogenesis and vascular remodeling in the small intestine.