Resveratrol reduces albuminuria in diabetic nephropathy: A randomized double-blind placebo-controlled clinical trial

Aim. - Albuminuria is the most important indicator of diabetic nephropathy (DN). Resveratrol, a natural compound found in grape skins and red wine, has antioxidant effects. This study aimed to evaluate the effects of resveratrol on DN. Methods. - In this randomized, double-blind, placebo-controlled clinical trial, 60 patients with type 2 diabetes and albuminuria were randomly assigned to receive either resveratrol (500 mg/day) or placebo for 90 days. Losartan (12.5 mg/day) was also administered to all participants. Primary outcomes were urinary albumin/creatinine ratio, estimated glomerular filtration rate (eGFR) and serum creatinine levels. Secondary outcomes were oxidative stress markers, and anthropometric and biochemical measures. Results. - Mean urine albumin/creatinine ratio was significantly reduced in the resveratrol group vs placebo (-46.4 mg/g, 95% CI: -64.5 to -28.3 vs 29.9 mg/g, 95% CI: 4.9 to 54.9; P < 0.001), whereas eGFR (1.7 mL/min/1.73 m(2) , 95% CI: -3.4 to 6.8 vs -4.0, 95% CI: -8.2 to 0.2; P= 0.08) and serum creatinine (-0.3 mg/dL, 95% CI: -0.1 to 0.1 vs 0.1 mg/dL, 95% CI: -0.0 to 0.1; P= 0.13) were unchanged. Serum antioxidant enzymes were significantly increased with resveratrol. After adjusting for confounding variables, the effect of resveratrol in reducing urinary albumin excretion was still significant (P < 0.001). Regression analysis revealed that every 1-cm decrease in waist circumference and 1-mu mol/L increase in nitric oxide (NO) was associated with 9.4 mg/g and 4.0 mg/g reductions, respectively, of urine albumin/creatinine ratio. Conclusion. - This clinical trial has shown that resveratrol may be an effective adjunct to angiotensin receptor blockers (ARBs) for reducing urinary albumin excretion in patients with DN (C) 2018 Elsevier Masson SAS. All rights reserved.