[Intermediate filament patterns of the nephron and the urothelium]

Abstract

The expression of intermediate filament (IF) proteins (vimentin and individual cytokeratins [CKs]) has been studied in the normal human kidney using immunohistochemical methods. For CKs 19 and 7, a conspicuously alternating pattern of positive and negative tubule segments was found, suggesting an inverse relationship between epithelial specialization and extent of the CK cytoskeleton. Coexpression of CKs and vimentin (typical of the common types of renal cell carcinomas) was found in fetal but not in adult proximal tubules. The surface epithelium of the adult renal papilla was characterized by the presence of basal cells expressing certain stratification-related CKs. These data underline the correlation of IF protein expression not only with the epithelial cell type but also with its developmental and functional state.