ANTIOXIDANT EFFECTS OF TOCOTRIENOLS IN PATIENTS WITH HYPERLIPIDEMIA AND CAROTID STENOSIS

Antioxidants may have a role in the prevention of atherosclerosis. in the present trial, we investigated the antioxidant properties of Palm Vitee, a gamma-tocotrienol-, and a-tocopherol enriched fraction of pal m oil, in patients with carotid atherosclerosis. Serum lipids, fatty a cid peroxides, platelet aggregation, and carotid artery stenosis were measured over an 18-month period in fifty patients with cerebrovascula r disease. Change in stenosis was measured with duplex ultrasonography . Ultrasound scans were done at six months, twelve months, and yearly thereafter. Bilateral duplex ultrasonography revealed apparent carotid atherosclerotic regression in seven and progression in two of the 25 tocotrienol patients, while none of the control group exhibited regres sion and ten of 25 showed progression (P < 0.002). Serum thiobarbituri c acid reactive substances, an ex vivo indicator of maximal platelet p eroxidation, decreased in the treatment group from 1.08 +/- 0.70 to 0. 80 +/- 0.55 mu M/L (P < 0.05) after 12 mon, and in the placebo group, they increased nonsignificantly from 0.99 +/- 0.80 to 1.26 +/- 0.54 mu M/L. Both tocotrienol and placebo groups displayed significantly atte nuated collagen-induced platelet aggregation responses (P < 0.05) as c ompared with entry values. Serum total cholesterol, low density lipopr otein cholesterol, and triglyceride values remained unchanged in both groups, as did the plasma high density lipoprotein cholesterol values. These findings suggest that antioxidants, such as tocotrienols, may i nfluence the course of carotid atherosclerosis.