EFFECTS OF SUPPLEMENTING WITH VITAMIN-E ON THE UPTAKE OF LOW-DENSITY-LIPOPROTEIN AND THE STIMULATION OF CHOLESTERYL ESTER FORMATION IN MACROPHAGES

Vitamin E supplementation has been reported to protect low density lip oprotein (LDL) from copper-induced oxidation and macrophage-mediated o xidation. We investigated the effect of in vitro vitamin E enrichment of LDL on the accumulation of [H-3]cholesteryl ester (CE)-LDL and stim ulation of cholesteryl ester formation in J774 macrophages. Vitamin E supplementation prolonged lag time (2.9-fold) before the initiation of copper-induced LDL oxidation. LDL, preincubated with 5 mu M copper or with macrophages in Ham's F10 medium, accumulated in macrophages much more than did native LDL. However, following vitamin E enrichment, LD L accumulation was significantly reduced following oxidative stress. V itamin E-enriched LDL also reduced the stimulation of cholesteryl este r formation in macrophages. Moreover, vitamin E enrichment of macropha ges reduced the ability of the cells to oxidize LDL. The present resul ts indicate that vitamin E supplementation protects LDL against copper -induced and macrophage-mediated oxidation, inhibits oxidation-depende nt accumulation of LDL in macrophages, and prevents stimulation of cho lesteryl ester formation in macrophages. Additionally we have provided evidence that intra-cellular enrichment with vitamin E prevents oxida tive modification of LDL by macrophages.