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 wounding model and the possible protection afforded by vitamin E (E). Endothelial cells grown on micropore filters were wounded by scraping and allowed to reestablish growth on denuded areas in the presence of LDL or oxLDL (25-200 mu g/ml), linoleic acid (FA, 90 mu M) or linoleic acid hydroperoxide (OFA, 15 mu M) for 24 h. Some monolayers were pretreated with 25 mu ME for 24 h. Transendothelial albumin movement was used 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 regrowth, whereas native LDL was without effect and preenrichment with 25 mu M E offered no protection. In comparison, E preenrichment improved endothelial 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 unlikely to be involved in this effect.