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 lipoprotein (LDL) from copper-induced oxidation and macrophage-mediated oxidation. We investigated the effect of in vitro vitamin E enrichment of LDL on the accumulation of [3H]cholesteryl ester (CE)-LDL and stimulation 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 microM copper or with macrophages in Ham's F10 medium, accumulated in macrophages much more than did native LDL. However, following vitamin E enrichment, LDL accumulation was significantly reduced following oxidative stress. Vitamin E-enriched LDL also reduced the stimulation of cholesteryl ester formation in macrophages. Moreover, vitamin E enrichment of macrophages reduced the ability of the cells to oxidize LDL. The present results indicate that vitamin E supplementation protects LDL against copper-induced and macrophage-mediated oxidation, inhibits oxidation-dependent accumulation of LDL in macrophages, and prevents stimulation of cholesteryl ester formation in macrophages. Additionally we have provided evidence that intra-cellular enrichment with vitamin E prevents oxidative modification of LDL by macrophages.
CSIRO, Division of Human Nutrition, Adelaide, Australia.
M
M
Suzukawa
M
M
Abbey
P
P
Clifton
P J
PJ
Nestel
D001161:Arteriosclerosis / Q000188:drug therapy / Q000378:metabolism; D002788:Cholesterol Esters / Q000096:biosynthesis* / Q000378:metabolism; D005260:Female; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D018384:Oxidative Stress; D014810:Vitamin E / Q000494:pharmacology* / Q000627:therapeutic use
D002788:Cholesterol Esters; D008077:Lipoproteins, LDL; D014810:Vitamin E