Linoleic acid hydroperoxide increases the transfer of albumin across cultured endothelial monolayers.

Exposure to albumin-bound linoleic acid (60 to 150 microM) for 24 h significantly increased the rate of albumin transfer across cultured endothelial monolayers. The increase was dependent on the linoleic acid (18:2) concentration to which the cultures were exposed. Linoleic acid hydroperoxide (18:2-OOH) further accelerated the rate of albumin transfer over that of 18:2. A near maximum albumin transfer was observed after a 2-h incubation with 90 microM 18:2-OOH. Cells exposed to 18:2-OOH caused a marked release of lactate dehydrogenase into the media. On the other hand, 18:2 at concentrations as high as 150 microM, did not significantly affect lactate dehydrogenase release. These results suggest that exposure to 18:2, and in particular to 18:2-OOH, reduces the ability of the endothelium to act as a selective permeability barrier to plasma components.