Mechanisms and functions of intestinal vascular specialization

Abstract

The intestinal vasculature has been studied for the last 100 years, and its essential role in absorbing and distributing ingested nutrients is well known. Recently, fascinating new insights into the organization, molecular mechanisms, and functions of intestinal vessels have emerged. These include maintenance of intestinal epithelial cell function, coping with microbiota-induced inflammatory pressure, recruiting gut-specific immune cells, and crosstalk with other organs. Intestinal function is also regulated at the systemic and cellular levels, such that the postprandial hyperemic response can direct up to 30% of systemic blood to gut vessels, while micron-sized endothelial cell fenestrations are necessary for nutrient uptake. In this review, we will highlight past discoveries made about intestinal vasculature in the context of new findings of molecular mechanisms underpinning gut function. Such comprehensive understanding of the system will pave the way to breakthroughs in nutrient uptake optimization, drug delivery efficiency, and treatment of human diseases.

Protocol for three-dimensional whole-mount imaging of the vascular network in the intestinal muscle

“…The adult mouse intestine contains a complex and highly developed vascular network running throughout the intestinal wall. 4 , 5 These vessels provide blood to the various layers of the gastrointestinal tract, including the luminal adsorptive mucosa layer, the submucosa, and the muscularis propria ( muscularis ) which is the layer that provides peristaltic forces ( Figure 2 A). While excellent protocols have been described to investigate the vasculature within the intestinal submucosa and villi, 6 , 7 , 8 the vascular network within the intestinal muscularis is not well studied.…”