Antihypertensive Treatment Approaches and Oxidant-Antioxidant System Relationship in Hypertensive Type 2 Diabetic Patients

A relationship between endothelial dysfunction and oxidative stress has been shown in the pathogenesis of diabetes and/or hypertension. Antihypertensive drugs (angiotensin-converting enzyme inhibitors [ACEi], angiotensin II type 1 receptor blockers [ARB], and third-generation beta-blockers) can improve oxidative stress. This study evaluated the effects of losartan (ARB) treatment alone and combined with cilazapril (ACEi) or carvedilol on oxidative stress and antioxidants in hypertensive type 2 diabetic patients. Thirty of 56 patients completed the study. All patients received 50 mg losartan daily for 6 weeks, then were randomised into three groups for 6 weeks. In the first group, losartan was increased to 100 mg/day, and in the second and third groups, carvedilol or cilazapril was added to losartan 50 mg/day treatment, respectively. Apolipoprotein B malondialdehyde (basal and Δ-MDA), serum paraoxonase (PON) and arylesterase (AE), erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (Gpx) parameters were studied. The characteristics of the three groups were comparable (p>0.05). Blood pressure (BP) decreased significantly in all three groups before and after randomisation in the six-week periods. The largest BP decrease was seen in the ARB+ACEi group (systolic BP: 16.5±7.4 mmHg, diastolic BP: 10.5±2.8 mmHg), and the smallest decrease was seen in the high-dose ARB group (systolic BP: 9±6.1 mmHg, diastolic BP: 3±4.8 mmHg). Throughout the study, no significant changes were detected in basal and Δ-MDA levels and SOD, Gpx, PON and AE activities in inter- and intra-group comparisons. Our observations showed that different antihypertensive therapy approaches effectively lowered BP in hypertensive type 2 diabetics but did not affect oxidant and antioxidant systems in the short term.