Contractile pericytes determine the direction of blood flow at capillary junctions

Abstract

Significance Capillaries—the most abundant vessels in the circulatory system—deliver O 2 and nutrients to all cells of the body. In the brain and retina, capillaries also act as a sensory web that detects neuronal activity. Here, we demonstrate that pericytes localized at capillary junctions in a postarteriole transitional region possess unique properties, notably including contractility, that enable them to dynamically manipulate capillary branch diameters and exert fine control over the distribution of blood within the capillary network. In so doing, these contractile junctional pericytes fine tune the delivery of O 2 and nutrients and thus serve to meet the specific needs of neurons. Given these unique properties, pericytes represent a therapeutic target for cardiovascular and neurodegenerative diseases.