Fig. 1

Pathophysiology of endothelial cells. Endothelial cells exist in the inner layer of blood vessels (a) such as arteries (b), veins (c), and capillaries (d), and are normally protected by pericytes that support the vessel structure. Tight junctions link neighboring cells and help maintain tissue integrity, act as barriers to permeability. The regulation of vascular tone, and permeability upon activation are illustrated