engleski

THE EFFECTS OF CALCIUM CHANNEL AND AT1-BLOCKER ANTIHYPERTENSIVE THERAPY AND VITAMIN C/E TREATMENT ON THE LEVEL OF OXIDATIVE STRESS IN HYPERTENSIVE PATIENTS

Objective Previous studies reported increased oxidative stress in hypertension. The aim of this study was to assess if different antihypertensive therapies and addition of antioxidants (vitamin C and E) affect the levels of oxidative stress marker 8- iso-prostaglendin F2-alpha (8iPGF2α). An additional aim was to test whether supplementation of antioxidants can further decrease blood pressure (BP) by reducing the level of oxidative stress. Design and method 57 newly discovered hypertensive patients were randomly divided into two groups receiving AT1 antagonist olmesartan (10-20mg/day, N=27) or calcium channel blocker amlodipine (5-10mg/day, N=30). After 8 weeks of therapy patients from both groups were further subdivided according to addition of vitamin C/E or placebo. Serum levels of 8iPGF2α were measured by ELISA at the time of inclusion in the study and after 8 and 16 weeks of treatment. Data are presented as mean±SD, and were compared by Kruskal-Wallis Analysis of Variance or Mann-Whitney U test. Correlations were calculated using Person´s test (SigmaPlot v.11). P<0.05 was considered significant. Results BP was normalized in all patients during first 8 weeks of antihypertensive therapy, reaching 127.5±2.3/81.0±1.8 and 134.2±3.49/84.4±2.8 in olmesartan and amlodipine group, respectively. Additional 8 weeks of treatment did not affect BP levels, irrespectively of the antioxidative treatment with vitamins C/E. 8iPGF2α levels did not change significantly during first 8 weeks of treatment ; however, there was a significant reduction in 8iPGF2α levels after 16 weeks of treatment in both groups without any additional effects of vitamin treatment. 8iPGF2α levels positively correlated to systolic (r=0.406, p=0.0009) and diastolic (r=0.406, p=0.001) BP in amlodipine group, while only diastolic BP levels in olmesartan group (r=0.351, p=0.0038). Conclusions Normalization of BP during first 8 weeks of antihypertensive therapy was not followed by immediate reduction in oxidative stress, which occurs during additional 8 weeks of treatment. There was no difference in BP or 8iPGF2α levels between patients receiving AT1 antagonist and patients treated with calcium channel blocker. Addition of vitamin C/E during 8 weeks had no effect on BP or the level of oxidative stress in these patients.

hypertesnion; calcium channel blocker; AT-1 receptor blocker; oxidative stress; vitamin C; vitamin E

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