Ductular morphogenesis and functional polarization of normal human biliaryepithelial cells in three-dimensional culture

Backgrouund/Aims: The understanding of the physiology and function of human biliary epithelial cells (hBEC) has been improved by studies in monolayer culture systems. The aim was to develop a polarized model to elucidate the mechanisms of ductular morphogenesis and functional differentiation of hBEC . Methods: The morphological, phenotypic and functional properties of hBEC cu ltured as three-dimensional aggregates in collagen gel mere assessed in med ium supplemented with (or without) human hepatocyte growth factor (hHGF) an d foetal bovine serum. Results: In the absence of added mitogens and serum, cells maintained as mo rphologically polarized aggregates, organized around a central lumen, were positive for phenotypic markers of biliary epithelium and negative for mark ers of other cell types. Functional markers, gamma-glutamyl-transferase, an ion exchanger-2, responses to gamma interferon and forskolin induced secret ion, were preserved. hHGF increased both the size and number of aggregates and induced hBEC to invade the gel and lumena forming anastomosing networks of cells. Conclusions: Collagen gel culture in the absence of added growth factors an d serum provides a model for analysis of the polarized functions of hBEC. T he formation of poorly organized cords of cells in response to hHGF suggest s that collagen gel culture may provide a model for the investigation of at ypical ductular morphogenesis of the human biliary tract. (C) 2001 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.