Vitamin E administration improves impairment of endothelium-dependent vasodilation in patients with coronary spastic angina.

Abstract

We examined the effects of oral administration of vitamin E, an antioxidant, on endothelium-dependent vasodilation in patients with coronary spastic angina. We have recently reported that endothelium-dependent vasodilation is impaired in patients with coronary spastic angina (CSA). Furthermore, it is known that oxidative stress may play an important role in the impairment of endothelium-dependent vasodilation in cardiovascular diseases. With the ultrasound technique, flow-dependent vasodilation of the brachial arteries during reactive hyperemia was examined before and after treatment for a month with either oral administration of vitamin E (alpha-tocopherol acetate, 300 mg/day) or placebo, which is randomly assigned, in patients with CSA (n=60). Before treatment, patients with CSA had impaired flow-dependent vasodilation, lower plasma levels of alpha-tocopherol and higher plasma levels of thiobarbituric acid reactive substances (TBARS), as compared with age- and sex-matched control subjects (n=60) (flow-dependent vasodilation: 3.1+/-1.8 vs. 7.1+/-2.5%, p < 0.001; alpha-tocopherol levels: 8.9+/-1.8 vs. 10.8+/-1.8 microg/ml, p < 0.001). In patients with CSA, treatment with vitamin E restored flow-dependent vasodilation (3.1+/-1.7 vs. 8.3+/-2.0%, p < 0.001), and this improvement was associated with the decreases in plasma TBARS levels and anginal attacks. The results indicate that vitamin E treatment improved endothelium-dependent vasodilation and decreased plasma TBARS levels in patients with CSA. Thus, increased oxidative stress may contribute to endothelial dysfunction and anginal attacks in patients with CSA.