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M Kedinger

Publications and source records attributed to M Kedinger.

115 records · Page 7Linked to original sources
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Mesenchyme-dependent differentiation of epithelial progenitor cells in the gut.

The digestive tract and the gut as a paradigm represents an attractive system for the study of mechanisms involved in the differentiation of two types of progenitor cells: the endodermal cells during embryonic life and the undifferentiated crypt cells during epithelial renewal of the adult intestine. The morphological and functional events that accompany the differentiation processes of progenitor cells into the polarized epithelial cell types characteristic of the intestine appear comparable in both situations (1,2). During organogenesis of the gut, histological observations underlined a close relationship between epithelial cells and their underlying mesenchymal cells (3,4). Developmental biologists have emphasized experimentally the importance of interactions between the endoderm and mesenchyme during organogenesis of the digestive tract. In the adult intestine, gastroenterologists have focused their attention on a specialized mesenchymal cell type (the pericryptal fibroblasts) that displays, like epithelial cells, proliferative activities and migrating properties. The aim of this review is to provide current knowledge on epithelial-mesenchymal interactions during ontogenesis of the digestive tract and also to relate some experiments supporting the view of the perpetuation of epithelial-mesenchymal interactions beyond embryonic life.

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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.

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