Urinary TGF-β1 reduction related to a decrease of systolic blood pressure in patients with type 2 diabetes and clinical diabetic nephropathy

Abstract 

With the aim to determine the influence of reducing systolic blood pressure in urinary TGF-β1 of type 2 diabetes (DM2) with diabetic nephropathy (DN), 21 subjects with type 2 diabetes and proteinuria >500mg/24h were studied. Amlodipine and ramipril were added to their previous antihypertensive treatment for 12 weeks. Urinary TGF-β1 (UTGF-β1) was determined at 0, 4, 8 and 12 weeks. Plasma TGF-β1 was determined at 0 and 12 weeks. Subjects whose mean systolic blood pressure (SBP) during treatment were under 140mmHg were grouped as the better SBP controlled group (n=11) and those with SBP equal to or greater than 140mHg were grouped in a moderate SBP controlled group (n=10). Compared to baseline, mean log UTGF-β1 at 4, 8 and 12 weeks decreased (−0.22±0.15pg/mg; p=0.04) in better SBP controlled group but not in the moderate SBP controlled group (−0.12±0.08pg/mg, p=0.82). Mean SBP correlated with UTGF-β1 (r=0.458, p=0.0357), and this effect was independent of HbA1c (p=0.042). By controlling SBP in DM2 subjects with DN we might decrease UTGF-β1. We propose that reduction of UTGF-β1 is due to a decrease in renal TGF-β1 production.

Keywords: Diabetic nephropathy, TGF-β, Hypertension