Brain microvessel endothelial cells in tissue culture: A model for study of blood‐brain barrier permeability

Endothelial cells were prepared from bovine brain microvessels and grown in tissue culture. They contained factor VIII/von Willebrand antigen, the most specific marker available for determination of the endothelial origin of cells in culture. The cultured cells formed complex tight junctions and contained few pinocytotic vessels. These properties are responsible for formation of the blood‐brain barrier in vivo. When monolayers of the endothelial cells were exposed briefly to a calcium‐free solution or treated with 1.6 M arabinose, distinctive morphological changes occurred in the intercellular contacts. In either case, a normal structure was reestablished following return to control medium. To assess the effect of these treatments on transcellular permeability, we measured the movement of sucrose labeled with carbon 14 across a monolayer of endothelial cells cultured on a collagen‐coated nylon mesh. Removal of external calcium increased the rate of sucrose movement by 120%; the arabinose treatment increased transcellular flux by 40%.