Renal Glomerular Expression of WT-1, TGF-β, VEGF, and ET-1 Immunostains in Murine Models of Focal and Segmental Glomerulosclerosis

Abstract

Primary focal segmental glomerulosclerosis (FSGS) is a type of chronic renal disease that commonly progresses to renal failure as the treatments are not particularly effective. Glomerular podocyte injury and loss are pivotal to the pathogenesis of FSGS. This study aims to explore the glomerular immunohistochemistry stain expression of Wilms tumor-1 (WT-1) (podocyte-specific protein), transforming growth factor beta (TGF-β) (cytokine protein), vascular endothelial growth factor (VEGF) (angiogenic protein), and endothelin-1 (ET-1) (profibrotic growth factor), in rats with adriamycin nephropathy, which represents the murine model of human FSGS. By the end of 8 and 12 weeks, the kidneys of adriamycin-treated rats and control rats were harvested and the histomorphology was studied. Both 8- and 12-week test groups developed proteinuria, and hypoalbuminemia and showed FSGS on hematoxylin and eosin–stained slides. The renal tissue samples were also treated with immunostains for WT-1, TGF-β, VEGF, and ET-1. The glomeruli in all the FSGS kidneys showed loss of WT-1 expression with a concomitant notable increased expression of TGF-β, VEGF, and ET-1 immunostains. These results demonstrate that as FSGS evolves, the WT-1-expressing podocytes are lost and it correlates inversely with the overexpression of TGF-β, VEGF, and ET-1, suggesting that during the pathogenesis of FSGS, podocyte damage triggers the activation of these proteins. The findings in the current study echo the theory hypothesized in world literature that TGF-β, VEGF, and ET-1 play an integral part in the evolution of FSGS. More research is needed to further detail the pathogenic role of these proteins as it may open routes to more targeted and effective treatment modalities.