Urinary Detection of Podocyte and Associated Molecule in Different Podocyte Diseases

Objective:To detect podocyte injury in the urine of focal segmental glomeruloscleros (FSGS) and other podocyte diseases.Methods:Urinary samples were taken from 54 patients with FSGS,23 with membranous nephropathy(MN) and 12 with minimal-change disease(MCD)and samples from 20 healthy volunteers were served as controls.Freshly voided urine samples were examined by immunofluorescence labeling,using monoclonal antibody against human podocalyxin.Urinary sediment podocyte associated moculars mRNA expression were quantified by Real-time PCR, podocyte associated molecule-Wilms Tumor 1(WT1)protein expression were quantified by western blot.The expression of podocyte associated molecule-podocalyxin in glomeruli were determined by immunofluorescence.Results:NO podocyturia was found in healthy controls.The negative rate of patients with FSGS was 63%,that of patients with MN 34.8% and that of patients with MCD 33.3%.Patients with FSGS had significantly higher levels of urinary podocytes than those with MCD, MN and controls(P0.05).The FSGS patients with podocyturia showed significant difference in 24 h proteinuria,plasm albumin level(P0.05).The expression of nephrin mRNA in urinary sediment of FSGS was higher than those of MCD and MN(P0.05).There were significant differences in urinary sediment podocin mRNA expression between patients with FSGS and MCD,The expression of synaptopodin mRNA in urinary sediment was not significant differences among these groups.The expression of podocin, nephrin and synaptopodin mRNA in Urinary sediment were not correlated with proteinuria.Urinary WT1 was significantly higher in FSGS than those in the MN and MCD patients.WT1 were also detected in some patients without podocyturia.Depletion of podocalyxin expression on glomerulus of FSGS patients was significant compared with that in the controls, MN and MCD patients.Conclusion:The podocytes damage of FSGS was severer compared with those of MN and MCD.Urinary podocyte of FSGS patients also correlated with disease activity.MCD can be distinguished from FSGS and MN by the expression of nephrin mRNA in urinary sediment.Urinary WT1 protein might be a useful biomarker to detect early podocyte injury.