Figure 1

Illustration of the neurovascular unit (NVU) in the central nervous system. ( A ) The NVU comprises multiple cell types, including neurons, vascular smooth muscle cells, endothelial cells, astrocytes, microglia, and pericytes. Astrocytes and microglia release various factors (including TNF-α, IL-1β, IL-6, and VEGF), which act on neurons and endothelial cells. ( B ) Enlarged illustration of the interaction between astrocytes and endothelial cells. Under pathological conditions, several inflammatory cytokines (TNF-α, IL-1β, and IL-6) that are released by activated astrocytes may cause a positive feedback on the production of VEGF. These factors (TNF-α, IL-1β, IL-6, and VEGF) may collectively induce the proliferation of endothelial cells and lead to neurovascular abnormalities in brain disorders.