Primary cultures of human urothelial cells for genotoxicity testing

A cell culture system with human-derived urothelial cells was established based upon previous experience with cultures of porcine urinary bladder epithelial cells. Human tissue specimens used were derived from urinary bladders (n = 17) or ureters (n = 50) of patients undergoing urological operations. The epithelial origin and differentiation status was evaluated by an immunohistochemical staining for cytokeratins 7, 8, 18, 19, and 20 for isolated and cultured cells. Specimens from human ureters were better suited for primary cell cultures of the urothelium than specimens from human urinary bladders. Successful attachment and proliferation were reached by 98% of the ureter specimens (urinary bladder: 71%) and confluency was reached by 78% of the ureter cultures (urinary bladder: 18%). In the first 14 d of culture the cytokeratin patterns of cultured cells were comparable to those of native mucosa cells. During prolonged cell culture the cytokeratin patterns of the human urothelial cells (HUC) changed into a beginning dedifferentiation: Cytokeratin (CK) 18 was only detectable in cell cultures cultured for more than 29 d, whereas CK 19 was not detectable at d 29. Cell cultures of primary human urothelial cells may be used for in vitro testing of cytotoxic or genotoxic effects.