Transforming growth factor‐β (TGF‐β) activity in urine of patients with glomerulonephritis is related to their renal functional and structural changes

Abstract

Transforming growth factor‐β (TGF‐β) has been considered the principal cytokine involved in the pathogenesis of renal fibrosis. In the present study, we evaluated TGF‐β activity in occasional samples from 22 normal individuals and 29 patients (11 with focal glomerulosclerosis, 11 with membranous nephropathy, five with Berger disease, one with type I membranoproliferative glomerulonephritis and one with postinfectious glomerulonephritis) using a CCL‐64 mink lung cell growth inhibition assay.A significantly increased urinary TGF‐β activity (reported in relation to urine creatinine, Ucreat. and median) was observed in patients with glomerulonephritis compared with normal individuals (P<0.01). The patients with Berger disease [median (Md)=9.96/10 μg Ucreat.], membranous glomerulonephritis (Md=7.23/10 μg Ucreat.) and focal glomerulosclerosis (Md=16.6/10 μg Ucreat.) showed higher urinary TGF‐β than normal individuals (Md=1.09/10 μg Ucreat.) (P<0.01). We found a positive correlation between the TGF‐β activity in the urine of these patients and the incidence of segmental glomerulosclerosis (r=0.45, P<0.05) and their plasma creatinine levels (r=0.87, P<0.01). A negative correlation was observed between the TGF‐β activity in the urine of these patients and their creatinine clearance (r=−0.75, P<0.01).Our data suggest that measurement of urinary TGF‐β activity could be a useful non‐invasive procedure for the evaluation of renal TGF‐β production, permitting the assessment of prognosis and the evaluation of therapeutic efficacy in patients with renal disease.