Cultures of exfoliated epithelial cells from different locations of the human urinary tract and the renal tubular system

Exfoliated human urinary tract epithelial cells and renal tubular cells fro m urinary sediments of healthy adults, of urological patients and of intern al patients were isolated and cultured. Cells started proliferating within 1 week after seeding a sediment. Proliferating cells formed colonies of dif ferent morphologies, designated as type-1 or type-2 cell colonies. Type-1 c ell colonies showed irregular contours and spindle-like cells within the co lonies. Subcultivation of type-1 cells for up to six passages was possible. Type-2 cell colonies showed smooth-edged contours and subcultivation was n ot possible. The epithelial character of type-1 cells was demonstrated by p ositive immunohistochemical staining for cytokeratin-7. In contrast to carb onic anhydrase-positive stained Madin Darby canine kidney cells (MDCK), whi ch were used as positive controls for renal tubular cells, type-1 cells wer e carbonic anhydrase-negative on staining with the cobalt phosphate method. This indicates that type-1 cells were not of renal tubular origin. Type-2 cells were positively stained for carbonic anhydrase, indicating that type- 2 cells were renal tubular cells. Type-2 cell colonies could be assigned to two subgroups with different cell forms. Colonies of cobblestone-like cell s more often occurred than type-2 cell colonies with spindle-like cells, wh ich are described in this study for the first time. Colonies with cobblesto ne-like cells formed domes (hemicysts), whereas spindle-like type-2 cell co lonies did not. Cultures of urinary sediments from healthy adults, elderly multimorbid patients treated with furosemide, and urological patients with urolithiasis treated with sulfamethoxazole/trimethoprim and/or with a percu taneous nephrostomy catheter were compared. In 52% of all cultured sediment s from healthy adults, in 30% of those from multimorbid patients, and in 75 -80% of those from urological patients cells proliferated to colonies. The ratios of type-1 to type-2 cell colonies were 3.3:1 (healthy adults), 1.4:1 (urological patients with urolithiasis), and 1.8:1 (urological patients wi th urolithiasis, urine was directly collected from the renal pelvis with a percutaneous nephrostomy catheter). Successful cultures of the urinary sedi ments from these three groups revealed means of 3 or 4 colonies, 14 colonie s, and 21 colonies, respectively. Differences in the number of colonies in relation to sex were observed only for the group of urological patients. It was shown that type-1 cells were urothelial cells, which did not show morp hological differences due to their locations of origin within the urinary t ract, whereas type-2 cells were probably renal tubular cells. These finding s offer new aspects in the culturing of human urothelial or kidney epitheli al cells with a method based on noninvasive collecting of specimens and req uiring only minimal culture effort. The cultures obtained by this method ca n be used for in vitro studies in toxicological and clinical research.