The Effects of Blocking Angiotensin Receptors on Early Stages of Diabetic Nephropathy

BACKGROUND: This study aimed to investigate the beneficial effects of angiotensin receptor blockers (ARBs) on markers of endothelial function in patients with early stage of diabetic nephropathy (DN). METHODS: This cross-sectional study was conducted on 32 participants with IDDM from January 2010 until May 2011 in Isfahan, Iran. The participants were candidate for receiving ARBs or angiotensin-converting enzyme inhibitors (ACEIs) to decrease microalbuminuria. The inclusion criteria were as follows: the age of onset of insulin-dependent diabetes mellitus (IDDM)less than 15 years; normal glomerular filtration rate (GFR); normal blood pressure; normal cardiovascular examination; negative urine culture, receiving no medications except insulin. Microalbuminuria was measured in two fasting urine samples with a sampling interval of at least 1–2 months by ELISA method. Patients with two abnormal results were included. Microalbumin to creatinin ratio equal to or more than 30 mg/gm was considered abnormal. The fasting blood samples to determine serum nitric oxide (NO) and vascular cell adhesion molecule (VCAM) were obtained at the time 0 (before starting the study), and after 2 months of receiving ARBmedication. Valsartan tablet (Diovan, Novartis Company) with a dose of 1 mg/kg/day up to 80 mg/day in a single dose was administered. RESULTS: Urine microalbumin to creatinin ratio after valsartan consumption was lower than microalbumin level before the medication, P < 0.05. After valsartan consumption, serum VCAM-1 level reduced and NO level increased significantly, P < 0.05. CONCLUSION: Angiotensin receptor blockers may reduce VCAM-1 and microalbuminuria and may increase NO levels in early stages of DN. Thus administration of ARBs might be considered even in early stages of DN.