Progressive morphogenesis in vivo after transplantation of cultured small bowel epithelium.

An experimental model for the primary culture and transplantation of late foetal rat small intestinal epithelium is described. Multicellular aggregates of mucosal epithelium containing pre-crypt proliferative cells were isolated from 20-day foetal rat intestine by enzymatic disaggregation. Cellular aggregates, which we refer to as "epithelial organoids," attached readily in culture, proliferated, and spread to produce coalescing colonies within 10 days. Enterocytes were maintained in culture for 3 days, removed as cell sheets, and incubated overnight with foetal mesenchyme. Fourteen recombinant preparations were then grafted to the renal subcapsular space of adult nude mice. Four of six grafts retrieved after 1 wk had developed. Histology demonstrated the formation of simple tubular structures lined by a polarized columnar epithelium. At 14 days, two of eight grafts had developed and demonstrated temporal progression of morphogenesis. Histology showed rudimentary crypts and villi lined by different epithelial cell types, including enterocytes and goblet cells. Small bowel proliferative cells within "epithelial organoids" from 20-day foetal intestine, may be maintained in primary culture for up to four days. After short term primary culture, these proliferative cells retain the capacity for progressive organotypic morphogenesis and pluripotent cytodifferentiation, after transplantation to adult recipients.