Effects of alpha-tocopherol on superoxide production and plasma intercellular adhesion molecule-1 and antibodies to oxidized LDL in chronic smokers

Antioxidants have been postulated to exert beneficial effects in atheroscle rosis. Atherosclerosis is associated with raised plasma levels of soluble i ntercellular adhesion molecule-1 (sICAM-1) and autoantibodies against oxidi zed low-density lipoprotein (oxLDL). It is not known whether antioxidants a ffect these plasma factors in chronic smokers. In a randomized double-blind placebo-controlled study involving 128 male normolipidemic chronic smokers the effect of a 2-year alpha -tocopherol treatment (400 IU dL-alpha -tocop herol daily) on plasma levels of sICAM-1 and autoantibodies against oxLDL w as evaluated. In addition. we monitored production of superoxide by leukocy tes ex vivo. It was found that compared to nonsmokers (n = 33) plasma level s of IgG but not IgM autoantibodies against oxLDL and concentrations of sIC AM-1 in smokers were significantly elevated (30 and 42%, respectively). Aft er supplementation with alpha -tocopherol concentration of TBARS in plasma and in vitro oxidizability of LDL had decreased, but autoantibodies and sIC AM-1 had not changed. Production of superoxide was not different between al pha -tocopherol- and placebo-treated smokers. It is concluded that in chron ic smokers. long-term treatment with alpha -tocopherol does not normalize t he raised levels of sICAM-1 and autoantibodies against oxLDL, both risk fac tors for initiation or progression of cardiovascular disease, despite a dec rease in in vitro oxidizability of LDL. (C) 2001 Elsevier Science Inc.