Lipid peroxidation and antioxidant vitamins C and E in hypertensive patients

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Abstract
Summary Lipid peroxidation is a free radical process which is implicated in the formation of atherosclerosis. Vitamins C and E are important natural antioxidants which inhibit lipid peroxidation and a high intake of these vitamins, particularly vitamin E, is related to a reduced incidence of ischaemic heart disease. Hypertension is an independent risk factor for atherosclerosis and its relationship to antioxidant status is undetermined. In this study, we investigated free radical activity by measuring plasma malondialdehyde (MDA) using high-performance liquid chromatography (HPLC), vitamin C status measured as plasma ascorbic acid and vitamin E status measured as plasma lipid standardized α-tocopherol and erythrocyte α-tocopherol. We compared 28 patients with essential hypertension to 31 healthy subjects. Results showed that in comparison with the healthy subjects, the hypertensive patients had significantly higher plasma MDA levels (0.95 α 0.28 vs 0.69 α 0.21 μmol/l, mean μ SD, p<0.001) and significantly lower levels of plasma ascorbic acid (34.83 μ 12.88 vs 51.76 μ 13.34 μmol/L, p<0.01). In addition, erythrocyte α-tocopherol concentration, which may reflect vitamin E protection in cell membranes, was significantly lower in hypertensive patients when compared with the normotensive controls (3.87 α0.53 vs 4.82 α 1.01 μmol/l, p<0.001), although plasma α-tocopherol levels were similar in the two groups (25.07 α 10.45 vs 23.96 α 6.07 μlmol/1). Our results suggest that hypertensive patients may have increased lipid peroxidation and reduced protection from vitamins C and E. This may contribute to the propensity in such patients to develop atherosclerosis.