Glial regulation of the blood-brain barrier in health and disease

The brain is the organ with the highest metabolic demand in the body. Therefore, it needs specialized vasculature to provide it with the necessary oxygen and nutrients, while protecting it against pathogens and toxins. The blood-brain barrier (BBB) is very tightly regulated by specialized endothelial cells, two basement membranes, and astrocytic endfeet. The proximity of astrocytes to the vessel makes them perfect candidates to influence the function of the BBB. Moreover, other glial cells are also known to contribute to either BBB quiescence or breakdown. In this review, we summarize the knowledge on glial regulation of the BBB during development, in homeostatic conditions in the adult, and during neuroinflammatory responses.