Expression of podocyte related proteins, TGF Beta-1, WT-1 in focal segmental glomerulosclerosis and minimal change disease, correlation of histological and clinical parameters

After the identification of the role of podocyte related molecules in glomerular filtration barrier and the detection of nephrin gene mutation which causes heavy proteinuria in congenital nephrotic syndrome, the assessment of these proteins in acquired nephrotic syndrome cases have also come into question. In the present study we examined the expression and clinical relevance of `slit diaphragm? proteins including nephrin, podocin and synaptopodin in cases of minimal change disease, focal segmental glomerulosclerosis and mesangial proliferation, in which podocyte damage is the common feature. 84 cases, 10 of which were controls were included in the study. We detected coarse granular staining with nephrin, podocin and synaptopodin in cases of focal segmental glomerulosclerosis, fine granular staining in cases of minimal change disease and both coarse and fine granular staining in cases characterized by mesangial proliferation, which was in between focal segmental glomerulosclerosis and minimal change disease. Podocin staining intensity and the loss of nephrin expression were correlated with creatinine clearance and blood creatinine levels. When the expression of TGF-ß1 in podocytes, which functions in extracellular matrix increase and apoptosis, was examined, cases of focal segmental glomerulosclerosis displayed a mild increase compared to other groups. There was a correlation between TGF expression and segmental sclerosis, global sclerosis, interstitial inflammation, fibrosis and tubular atrophy. Glomerular expression of WT-1 in cases of focal segmental glomerulosclerosis was mildly decreased compared to other groups, reflecting podocyte loss. We detected CD68 expression only in a few cases which did not express WT-1 and were in the stage of basal membrane separation and one of these cases was of cellular variant.In conclusion, although afore mentioned markers rather reflect podocyte damage and extend and severity of the disease, they expressed a similar or related staining pattern and they are important to enlighten the pathogenesis and confirm diagnosis.