FATTY-ACID COMPOSITION OF BRAIN CAPILLARY ENDOTHELIAL-CELLS - EFFECT OF THE COCULTURE WITH ASTROCYTES

We have investigated the fatty acid composition of brain capillary end othelial cells cultured alone or in coculture with astrocytes, using a n in vitro model in which endothelial cells and astrocytes were grown from one part of a filter to another. We found that the fatty acid com position of the cocultured cerebral endothelial cells was markedly dif ferent from that of non-cocultivated endothelial cells. The most strik ing difference was the increase of arachidonic acid (20:4n-6) at the e xpense of its precursor, linoleic acid (18:2n-6). Similar modification s were found for the n-3 family of fatty acids with an increase of doc osahexaenoic acid (22:6n-3) at the expense of its precursors, but the differences were less than within the n-6 fatty acids. These changes i nduced by the coculture were observed only in endothelial cell phospho lipids, especially the phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine classes, but were not detected in phosphatidyli nositols and in other lipid classes. Only the composition of the n-3 s eries fatty acids was altered in another capillary endothelial cell ty pe (from adrenal cortex) cocultured with astrocytes under the same con ditions. The fatty acid changes observed might be biologically relevan t as they tended to make the fatty acid composition of the brain capil lary endothelial cells more closely resemble that of brain microvessel s.