Alpha‐tocopherol protects against monocyte Mac‐1 (CD11b/CD18) expression and Mac‐1‐dependent adhesion to endothelial cells induced by oxidized low‐density lipoprotein

Abstract

Alpha-tocopherol supplementation is reported to protect against cardiovascular disease and to influence cells involved in atherogenesis, such as monocytes. Interactions between monocytes and vascular endothelial cells occur early in atherogenesis, and adhesion is mediated by integrins. We evaluated the effects of alpha-tocopherol on expression of Mac-1 (CD11b/CD18) by monocytes after stimulation with oxidized low-density lipoprotein (LDL), which is implicated as a potent chemotactic agent in atherogenesis. Incubation of whole blood with oxidized LDL (100 microg/ml) increased Mac-1 expression on monocytes, and preincubation with alpha-tocopherol reduced this upregulation in a concentration dependent manner. In another experiment, whole blood was obtained from healthy adult volunteers after 10 days of alpha-tocopherol administration (600 mg/day) and was incubated with oxidized LDL (100 microg/ml). There was a decrease in the upregulation of Mac-1 compared with that measured before administration. Adherence of oxidized LDL-stimulated monocytes to human umbilical vein endothelial cells was reduced by pretreatment with alpha-tocopherol, and was also inhibited by an anti-CD18 monoclonal antibody. Experiments with protein kinase C inhibitors suggested that reduction of Mac-1 upregulation by alpha-tocopherol was secondary to a decrease of protein kinase C activity. In conclusion, alpha-tocopherol suppressed the upregulation of Mac-1 expression on monocytes by oxidized LDL.

Green Tea and Heart Health

“…14,15 In addition, we have shown in both in vitro and ex vivo studies that a-tocopherol/tocotrienols decreases the expression of CD11b/CD18 on human monocytes induced by oxLDL. [14][15][16][17] These data support the hypothesis that antioxidants including vitamin E may reduce the extent of the oxLDL-induced monocyte-endothelial interaction and thus be protective against atherosclerosis.…”

Tocotrienols and Atherosclerosis

“…pherol decreased the expression of CD11b/CD18 on human neutrophils and monocytes induced by oxLDL in both in vitro and ex vivo studies [2][3][4]. These data support that vitamin E supplementation may reduce the extent of the oxLDL-induced monocyte-endothelial interaction and, thus, be protective against atherosclerosis.…”

Effects of Genistein on Oxidative Injury in Endothelial Cells

“…␣-Tocopherol is believed to have a cytoprotective effect, which is attributed to its ability to prevent leukocyte-endothelial interactions (27)(28)(29), and to act as a scavenger of highly reactive oxygen radicals in various pathophysiological processes (30,31). ␣-Tocopherol protects against apoptosis not only by scavenging reactive oxygen species, but also by inhibiting caspase activity, which means that its activity may exceed that of a mere antioxidant (22).…”