Abstract
The pericytes play a very important role in the central nervous system (CNS), concerning the formation of the functional neurovascular unit, serving as a substantial component in the development and maintenance of the stability of the blood-brain barrier (BBB). Besides, as pluripotent cells of neuroectodermal origin, the pericytes participate in autoimmune reactions and modulations, controlling the penetration of immune cells via BBB and playing an active role in lymphocytic trafficking and functional regulation, via cytokine secretion and activation. In demyelinating conditions, they participate in the restoration of the myelin sheath by modulating oligodendrocytes and stimulating the differentiation of oligodendrocyte progenitors. In the experimental model of allergic encephalomyelitis (EAE), electron microscopy reveals the proliferation and the morphological alterations of the pericytes as well as their interactions with endothelial cells and astrocytes, thus underlining the crucial role that pericytes play in the integrity of the BBB and the immune reactions of the CNS.