Blood-brain barrier formation of grafted human umbilical vein endothelial cells in athymic mouse brain

Human umbilical vein endothelial cells (HUVECs) were transplanted in athymic mouse brain and neovascularization of grafted endothelial cells was studied. HUVECs were transfected by a reporter gene pEGFPE-N1 in vitro and grafted stereotactically in unilateral striatum of adult nude mice. Histological studies in 4 weeks revealed that grafted HUVECs newly formed microvessels in brain, which were migrated and fused with host vessels. Intravenous injection of Evans blue before sacrificing animals resulted in no extravasation of dye, indicating that a blood-brain barrier (BBB) was formed by the grafted HUVECs. Immunohistochemistry demonstrated that host astrocytes extended glial feet on the grafted endothelial cells and a part of the newly formed vessels was positive with glucose transporter-1. These results indicate that endothelial cells from an ectopic origin have the potential to form a BBB after grafting in the central nervous system.