Renoprotective Effects of Various Angiotensin II Receptor Blockers in Patients with Early-Stage Diabetic Nephropathy

Background: There is increasing evidence that inhibition of the renin-angiotensin system provides renoprotection independent of blood pressure lowering. The aim of the present study was to determine whether various angiotensin II receptor blockers (ARBs) affect urinary albumin excretion (UAE), urinary liver-type fatty acid-binding protein (L-FABP) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in early-stage diabetic nephropathy patients with microalbuminuria. Methods: Sixty-eight diabetic nephropathy patients with microalbuminuria were randomly allocated to 1 of 4 treatment groups: losartan 100 mg/day (group A), candesartan 12 mg/day (group B), olmesartan 40 mg/day (group C), or telmisartan 80 mg/day (group D). Treatment was continued for 12 months. UAE, L-FABP and 8-OHdG excretion, serum creatinine, and 24-hour creatinine clearance (Ccr) were measured. Results: The serum creatinine and 24-hour Ccr were not affected during the experimental period in any of the groups. Systolic and diastolic blood pressures, UAE, urinary L-FABP and 8-OHdG excretion were significantly reduced after 6 and 12 months compared with baseline in any of the groups. Delta L-FABP and Delta 8-OHdG were significantly greater in group D than in the other 3 groups after 12 months. Conclusions: ARBs have renoprotection and this effect of telmisartan appears to be more potent than that of losartan, candesartan, or olmesartan in early-stage diabetic nephropathy patients. Copyright (C) 2010 S. Karger AG, Basel