HUMAN FETAL ASTROCYTES INDUCE THE EXPRESSION OF BLOOD-BRAIN-BARRIER SPECIFIC PROTEINS BY AUTOLOGOUS ENDOTHELIAL-CELLS

The blood-brain barrier (BBB) is involved in many normal regulatory me chanisms as well as in pathologic conditions of the central nervous sy stem. Previous studies examining the development and function of the B BB in vitro have primarily utilized cell lines or cultured tissues fro m non-human sources. In contrast, this study used a coculture system o f human fetal astrocytes and autologous endothelial cells. Astrocytes and endothelial cells (EC) were isolated and cultured on the opposite sides of a synthetic permeable membrane. The cocultures were character ized by electron and light microscopy for morphology and by immunocyto chemistry for cell-type specific markers. Using these coculture condit ions, astrocytes displayed characteristic morphology and expressed gli al fibrillary acidic protein. When cocultured with astrocytes, endothe lial cells retained factor VIII expression and expressed the BBB-speci fic proteins, brain-type glucose transporter (GLUT-1) and gamma-glutam yl transpeptidase. This expression was dependent on EC being in close apposition to or in direct contact with astrocytes. The model presente d in this study may permit further examination of the role of the BBB in both normal human neurodevelopment and neuropathologic conditions.