Study on the antioxidative effect of losartan at increasing dose in diabetic nephropathy / 中华肾脏病杂志

ABSTRACT

Objective To understand the situation of oxidative stress among diabetic nephropathy (DN) patients and observe the antioxidative effect of losartan at increasing dose in DN patients. Methods Thirty type 2 DN patients who neither smoked and nor took antioxidants were selected. The study began with an initial 4-6 weeks screening-treatment. Eligible patients then received losartan 50 mg/d daily for 8 weeks followed by losartan 100 mg/day daily for an additional 8 weeks. Blood glucose and blood pressure were closely monitored over the whole study period. All patients were followed up every other weeks, their 24-hour urine samples,fresh urine and venous blood sample were collected to measure urinary protein and creatinine excretion, urinary 8-OHdG, SOD, TAOC and MDA excretion , serum SOD, TAOC , MDA and other blood biochemistry parameters. Urinary 8-OHdG was determined by capillary electrophoresis and liquid phase chromatography. Results The total 24 hours urinary 8-OHdG excretion and the serum MDA concentration were higher than the normal values. The serum and urine SOD concentrations were lower than the normal values. There was an improvement in urinary 8-OHdG,serum and urine SOD, serum and urine MDA levels with losartan therapy. Compared with losartan 50 mg/d, the antioxidative effect of losartan 100 mg/d was more noticeable. Obvious decrease in 24-hour proteinuria on exposure to losartan was found, without severe adverse effect. Conclusions Oxidative stress damage is active in DN patients. Losartan has antioxidative effect on DN patients. Compared with losartan 50 mg/d, the antioxidative effect of losartan 100 mg/d is more marked, without increasing side effect. Losartan's antioxidative effect may be involved in its beneficial mechanisms on DN.