Growth of human renal cortical tissue on collagen gel.

A model system for 3-dimensional "native-state" culture of tissues on collagen gels (Proc. Natl. Acad. Sci. USA 86:2013-2017; 1989) has been applied in this study to histologically normal human renal cortical tissue from 11 patients undergoing nephrectomy for renal cell carcinoma elsewhere in the kidney. Microbial contamination occurred in 12/90 cultures, the rest (78) were studied by visual inspection, histology, immunohistochemical analysis for pankeratin (epithelial cell origin), vimentin (mesenchymal cell origin), and p-glycoprotein (associated with proximal tubules), transmission electron microscopy (EM), incorporation of tritiated thymidine (3HTdR). In the first 10 days, explants showed 3HTdR-labeled cells in tubule structures. The surrounding gel was invaded by cells forming tubule structures, sometimes with basement membrane. Some of these cells showed labeling by 3HTdR and immunostaining positive for pankeratin and p-glycoprotein. EM showed well-polarized epithelial cells in tubule structures with tight junctions, interdigitating lateral processes, and microvilli characteristic of proximal and distal convoluted tubules. 3HTdR-labeled cells in tubule structures were observed even 2 mo. after Passage 1, 6 mo. after the initial explantation. Tubule growth was most active and fibroblast proliferation was negligible from 2 to 4 wk postexplantation. The proliferation of tubulelike cells and formation of tubulelike structures in this system represents an opportunity to study human renal cortical tissue in vitro, under conditions more closely resembling in vivo circumstances than are present in other in vitro systems suitable for long-term study. This model has potential use for in vitro toxicology studies and studies of renal physiology.