Determination and intervention of serum and urine transforming growth factor β_1 levels in early diabetic nephropathy

Objective To determine the serum and urine levels of transforming growth factor β1(TGF-β1)in early diabetic nephropathy(DN)and to compare the effects of losartan,simvastatin and combination of the both on TGF-β1 in DN patients.Methods Sixty-five diabetic patients with microalbuminuria were randomly divided into 3 groups to receive losartan,or simvastatin,or combined losartan and simvastatin.Another 29 healthy individuals were included as controls.After 12 weeks,the patients were evaluated for 24-hour urinary albumin excretion rate(UAER)using radio-active immunoassay,serum/urine levels of TGF-β1 using double antibody sandwich ELISA assay.Results Compared with healthy controls,early DN patients showed significantly higher serum and urine levels of TGF-β1(P0.01),which positively correlated with UAER(P0.01).Therapy with losartan or simvastatin,particularly with the both combined,resulted in reduction of UAER and serum/urine TGF-β1 levels of baseline(P0.05).Conclusion Losartan and simvastatin,alone or combined,showed significant reduction of serum and urine TGF-β1 levels found to be elevated in early DN.Levels of TGF-β1 may be used as a specific indicator for early diagnosis and treatment evaluation in DN.