Hypoxia-induced Restructuring of Brain Microvessels; 3D Imaging and Quantification of Capillaries

Abstract

Brain is an organ that is the most vulnerable to a lack of oxygen in the body. In response to hypoxia, brain microvessels enlarge a diameter of capillaries in vicinity of neurons and partially develops new connections. Previous studies focused on plastic changes in brain microvasculature with cellular interactions of glia and vascular endothelium during each process of cerebral angiogenesis, such as sprout, enlargement, and connection to pre-existing capillaries. It was found that astrocytic processes cover newly-formed vessels with a preserved integrity of blood-brain barrier. Other types of the glial cells play a role in connecting a newly-formed vessel to pre-existing capillaries. However, it remains unclear whether glial cells are functionally involved in a process of capillary sprouts under hypoxia. Future works need to clarify a sensing mechanism of oxygen environment with cellular interactions of glia and microvessels, and impact of microvascular restructuring on neural functions and energy metabolism.