Expression and role of transforming growth factor-β1 and matrix metalloproteinase 9 in IgA nephropathy children

Abstract

Objective To study the association of transforming growth factor-β1(TGF-β1), matrix metalloproteinase 9(MMP-9)in serum, urinary and renal tissue of IgA nephropathy(IgAN) in children.In order to explore the noninvasive and easy repeatable biomarker, for assessing the severity and disease progression in IgAN children. Me-thods Fifty-four children with biopsy-proven IgAN and 55 healthy normal children(healthy control group) were enrolled between Jul.2009 and Jan.2013.The IgAN group was divided into 3 clinical groups according to their clinical features: isolated hematuria(IH) group(IH group, 20 cases), hematuria and proteinuria(HP) group(HP group, 16 cases), and nephritic syndrome group(NS group, 18 cases). Patients were divided into 2 groups according to their Lee's pathologic classification: grade Ⅰ+ Ⅱ group(Lee's Ⅰ+ Ⅱ, 39 cases), and grade Ⅲ+ Ⅳ group(Lee's Ⅲ+ Ⅳ, 15 cases). There were no grade Ⅴ in the study.The injury of renal tubules and interstitium was divided into 0-Ⅲ grades according to Katafuchi pathologic classification.IgAN group was also divided into 4 groups according to their immunophenotype: IgA(7 cases), IgA+ IgG group(9 cases), IgA+ IgM group(10 cases), IgA+ IgG+ IgM group(28 cases). The expressions of TGF-β1 and MMP-9 of each group were measured by enzyme-linked immunosorbent assay(ELISA). Immunohistochemistry was used to measure the expressions of TGF-β1 and MMP-9 in the paraffin sections of 34 IgAN and 3 normal renal tissue, and ELISA was used to measure the levels of TGF-β1 and MMP-9 in serum and urine.SPSS 16.0 statistical software was used. Results The levels of TGF-β1 and MMP-9 in serum and urinary of the IgAN group were significantly higher than those in the healthy control group(all P 0.05). The serum TGF-β1 and MMP-9 levels in Lee's Ⅲ+ Ⅳ group were significantly higher than those in Lee's Ⅰ+ Ⅱ group(all P 0.05). The serum and urinary TGF-β1 and MMP-9 levels were no statistically significant in all immune classification(all P>0.05). The expressions of TGF-β1 and MMP-9 in renal tubules and interstitium of Katafuchi Ⅲ grade were significantly enhanced than those in Katafuchi Ⅰ grade. Conclusions The serum TGF-β1 and MMP-9 play an important role in the severity and progression of children with IgAN.TGF-β1 and MMP-9 may be two more noninvasive and easy repeatable biomarkers to be used in evaluating the progression of IgAN in children. Key words: IgA nephropathy; Transforming growth factor-β1; Matrix metalloproteinase 9; Renal tissue; Child