PHENOTYPIC AND CYTOGENETIC CHARACTERIZATION OF HUMAN BLADDER UROTHELIA EXPANDED IN-VITRO

A simple method for the harvest of bladder cell types from surgical sp ecimens was used to generate strains of normal human urothelial cells that could be reproducibly cultivated, passaged and extensively expand ed in serum-free medium. Immunostaining of the bladder epithelial cell s with broadly reacting anti-cytokeratin antibodies and with an anti-c ytokeratin antibody specific to cytokeratin 7, a transitional cell mar ker, indicated that they expressed a stable epithelial phenotype with serial passage. Low levels of immunostaining for E-cadherin and low le vels of E-cadherin messanger ribonucleic acid, as determined by Northe rn blot analysis, and strongly positive immunostaining with an anti-vi mentin antibody indicated collectively that the uroepithelial cells ex press a nonbarrier-forming phenotype under these culture conditions. H owever, when the urothelial cells were implanted subcutaneously into a thymic mice on biodegradable synthetic polymers, they formed multilaye red structures, suggesting that they retain the capability to differen tiate in a living host. The urothelial cells proliferated in an epider mal growth factor independent manner and expressed high levels of tran sforming growth factor-ct and amphiregulin messanger ribonucleic acids , suggesting the possibility of autocrine regulation of growth by epid ermal growth factor-like factors. Cytogenetic analysis indicated that urothelial cells cultured for 6 passages possessed a normal chromosoma l complement. These results demonstrate that primary cultures of autol ogous human bladder epithelial cells can be extensively expanded in vi tro and, consequently, might be used in cell transplantation strategie s for genitourinary reconstruction.