ABSTRACT
Background: Proteinuria is a major predictor for renal progression in IgA nephropathy (IgAN). Thiazolidinediones were demonstrated to reduce proteinuria in patients with diabetic nephropathy.Objective: To investigate the effect of pioglitazone (PGZ) in proteinuric IgAN using randomized, double-blinded approach.Methods: Forty-one biopsy-proven IgAN patients with proteinuria (≥ 0.5g/day) who were currently treated with renin angiotensin system inhibitors and had at least two out of four risk factors for progressive disease (male gender, blood pressure \>150/90 mmHg, creatinine clearance of 20-80 mL/min/1.73m², and chronicity index \> 1) were randomly assigned to receive either PGZ 30 mg/day (PGZ group; n=21) or placebo (control group, n=20) for 16 weeks.Results: Baseline characteristics of patients in both groups were comparable. Following 16-week treatment, proteinuria in the PGZ group was significantly lower than the control group, [1.2 vs. 2.1 g/day (p \< 0.05)]. Patients in the PGZ group also showed a significant reduction in urinary excretion of TGF-β (from 361.4 to 234.4 ng/gCr) and VEGF (from 1353.1 to 765.1 ng/gCr) after 16-week treatment (p \< 0.05, both).Conclusion: PGZ significantly reduced proteinuria, urinary TGF-β, and urinary VEGF in IgAN patients. These findings suggest that PGZ could have a role in the treatment of proteinuric IgAN. Further studies with larger cases and longer follow-up time are warranted.