OXIDIZED LOW-DENSITY LIPOPROTEINS DELAY ENDOTHELIAL WOUND-HEALING - LACK OF EFFECT OF VITAMIN-E

The purpose of this study was to examine the influence of oxidized low -density Lipoprotein (oxLDL) on endothelial regrowth in an in vitro wo unding model and the possible protection afforded by vitamin E (E). En dothelial cells grown on micropore filters were wounded by scraping an d allowed to reestablish growth on denuded areas in the presence of LD L or oxLDL (25-200 mu g/ml), linoleic acid (FA, 90 mu M) or linoleic a cid hydroperoxide (OFA, 15 mu M) for 24 h. Some monolayers were pretre ated with 25 mu ME for 24 h. Transendothelial albumin movement was use d as a measure of endothelial barrier function and as an indicator of endothelial monolayer regrowth. Exposure to levels of oxLDL as low as 25 mu g/ml for 24 h resulted in depressed endothelial monolayer regrow th, whereas native LDL was without effect and preenrichment with 25 mu M E offered no protection. In comparison, E preenrichment improved en dothelial regrowth to control levels in FA- and OFA-treated cultures, unlike oxLDL-treated cultures. It is concluded that circulating oxLDL may reduce regrowth of wounded endothelium and supplemental E may not offer protection. Moreover, fatty acids or their hydroperoxides are un likely to be involved in this effect.