The Detection Of Urinary Podocyte And Associated Molecular Nephrin In Pediatric Proteinuria Nephropathy

ObjectiveTo detect the urinary excretion amount of podocyte and its related protein nephrin in children with proteinuria nephropathy,then analysis the relevance of its changes with the clinical detection index in order to explore the clinical significance about the detection of the urinary podocyte and its related protein nephrin excretion in children with proteinuria nephropathy.MethodsUrinary samples were taken from 40 patients with primary nephrotic syndrome (PNS), 5 patients with IgA nephropathy (IgAN) ,6 patients with Henoch - Schonlein Purpura Nephritis (HSPN),6 patients with lupus nephritis (LN) in children and samples from 10 healthy volunteers wereserved as controls. Application of indirect immunofluorescence staining by using monoclonal antibody against human podocalyxin examine urine cells sediment. The expression of podocyte associated molecule nephrin in urine were determined by enzyme-linked immunosorbent assay (ELISA) and Western blotting.Measurement data were shown with mean±standard deviation ( x±s),that SPSS13.0 statistical software was used for statistical analysis, the results expressed by mean±standard deviation ( x(?)±s) . Using single factor analysis of variance (One-Way ANOVA) when compared among groups, apply spearman correlation analysis the relationship between the variable (multiple linear regression analysis), The difference was considered statistically significant when P <0.05.Results(1) No podocyturia was found in healthy controls.The negative rate of patients with PNS group was 32.5%,that of patients with IgA nephropathy group was 20% and that of patients with HSPN group 33.3%, patients with LN group 83.3%;Patients with LN group had significantly higher levels of urinary podocytes than those with HSPN,PNS,IgAN and controls group ( P < 0. 05) . The PNS patients with podocyturia showed Serum TP, ALB was lower than those PNS patients with urinary podocyte negative,the difference was statistically significant (P <0. 05);Serum Cr and urine protein creatinine ratio was significantly higher than those PNS patients with urinary podocyte negative (P <0. 05).(2) In control patients,nephrin was not detected in urine,LN groups urine levels of nephrin expression was significantly higher than the HSPN,PNS,IgAN and controls group,the difference was statistically significant (P <0. 05).(3) In severe proteinuria group,urinary excretion of nephrin was significantly higher than those with mild proteinuria group (P <0.01).(4) 17 patients have done renal biopsy,accroding to the pathological lesions they can be divided into minimal change disease (MCD) groups, mesangial proliferative segmental sclerosis (MSPGN) group and focal segmental glomerularselerosis (FSGS) group. The excretion amount of urinary nephrin in FSGS group children was significantly higher than the MSPGN group and MCD group (P <0.01).(5) The expression of urinary nephrin with urinary podocyte were significantly positive correlation (r = 0.996, P <0.05),with urinary albumin / creatinine was aslo significantly positively correlated(r=0.544,P=0.008).(6) Western blotting can be used to detect nephrin protein in urine, but it is the shear fragment, molecular weight of nephrin is about 43KD, the difference of nephrin expression in the urine between each disease group are consistent with the results of ELISA method.ConclusionUrinary podocytes and nephrin can be detected in varieties of children with proteinuria nephropathy;urinary podocytes and nephrin expression differences may be contribute to the differential diagnosis of FSGS and MCD,MSPGN; urinary podocytes and nephrin are associated with proteinuria nephropathy severity and the detection of urinary podocytes and nephrin can be used as a noninvasive method to evaluate the severity of proteinuria nephropathy.