The relationship between obesity and transforming growth factor beta on renal damage in essential hypertension

The aim of this study was to evaluate the effect of obesity on renal functions and the possible relationship between TGF-beta1 and obesity in hypertensive patients. Seventy newly diagnosed, hypertensive patients (male/female 36/34, aged 45.0 +/- 8.0 years) and 30 (male/female 17/13, aged 41.8 +/- 7.7 years) normotensive controls were included. Patients in both groups were analyzed for serum levels of glucose, creatinine, uric acid, lipids, and TGF-beta1. A 24-hour urine sample was also obtained; creatinine clearance rate and urinary albumin excretion (UEA) were investigated. TGF-beta1 levels were significantly higher (40.7 +/- 13.6 versus 34.2 +/- 12.1 pg/mL, P = 0.02), and creatinine clearance was significantly lower in patients compared with controls (98.9 +/- 25.5 versus 124.5 +/- 23.1 mL/min. per. 1.73 m(2), P = 0.001). Serum TGF-beta1 levels (45.2 +/- 14 versis 38.0 +/- 12.8 pg/mL, P = 0.03), creatinine clearance rates (109.8 29.9 versus 93.0 +/- 20.8 mL/min. per. 1.73 m(2), P = 0.001), and urinary albumin excretion (55.7 +/- 62.0 versus 12.7 +/- 12.6 mg/24 h, P = 0.002) were higher in obese hypertensive patients than in nonobese patients. In hypertensive patients, TGF-beta1 levels correlated with body mass index (r = 0.296, P = 0.01) and creatinine clearance (r = 0.238, P = 0.04). The results suggest that increased body mass index is associated with increased creatinine clearance, urinary albumin excretion, and TGF-beta1 levels in essential hypertension. In addition, TGF-beta1 is positively correlated with body mass index and creatinine clearance in patients with essential hypertension.