Objective: Nilvadipine, a calcium antagonist, has been shown to have antioxidant activity in vitro, but its effect on in vivo oxidation has not been assessed. The aim of this study was to investigate the antioxidant effect of this agent in vivo. The ratios of 7-keto cholestadien to cholesterol are believed to be an available marker of lipid peroxidation. Using these ratios, we have assessed the antioxidant effect of nilvadipine on low-density lipoprotein (LDL) in hypertensive patients with high risk of atherosclerosis. The risk factors of atherosclerosis may involve oxidation of LDL.
Methods: Fifteen healthy subjects (seven females and eight males aged 35-72 years, mean +/- SD = 55.3 +/-13.8 years) and fifteen hypertensive patients (seven females and eight males aged 45-80 years, mean +/- SD = 60.2 +/- 11.8 years) were recruited. Patients were treated orally with nilvadipine (4 mg b.i.d.) for 4 weeks. Cholesterol oxidation levels of LDL in patients before and after nilvadipine therapy and healthy subjects were studied.
Results: The ratios of 7-keto cholestadien to cholesterol in LDL of hypertensive patients before and 4 weeks after nilvadipine treatment and in healthy subjects were 6.5 +/- 1.6% (mean +/- SD), 3.8 +/- 1.2%, and 0.2 +/- 0.1%, respectively. There were significantly (P < 0.001) increased levels of cholesterol oxidation in LDL in patients with hypertension both before and after nilvadipine treatment compared with healthy subjects. However, there was a significantly (P < 0.001) decreased level of cholesterol oxidation in LDL in patients after nilvadipine treatment compared with patients before nilvadipine treatment.
Conclusion: Our data showed that nilvadipine may protect LDL cholesterol from in vivo oxidation in hypertensive patients with high risk of atherosclerosis.