Figure 1. Neurovascular unit and transcytosis at the BBB.
(A) Cross-section of the neurovascular unit depicting endothelial cells surrounded by pericytes and astrocytes on their abluminal side. (B) Schematic illustrating the two kinds of transcytosis in CNS endothelial cells: molecules with specific receptors on CNS endothelial cells such as insulin and transferrin undergo receptor-mediated transcytosis while molecules such as albumin get endocytosed through charged interactions and undergo adsorptive transcytosis.