Biocompatible hydrogel supports the growth of respiratory epithelial cells: Possibilities in tracheal tissue engineering

Extensive tracheal defect reconstruction is a major challenge in plastic an d reconstructive surgery. The lack of an epithelial lining on the luminal s urfaces of tracheal prostheses is among the major causes of their failure. Chitosan-gelatin hydrogels were synthesized for the development of biocompa tible, growth-supportive substrata for respiratory epithelial cells. We emp loyed J774 macrophages to test the immunocompatibility of this gel. The hyd rogel did not exert a cytotoxic effect on macrophages, as confirmed by tetr azolium reduction and neutral red uptake assay. Flow cytometric analysis of macrophages cultured on the hydrogel showed a comparable expression of act ivation markers CD11b/CD18, CD45, and CD14 to the control. Semiquantitative RT-PCR results showed an absence of upregulation of interleukin-6 (IL-6) a nd TNF-alpha in these macrophages with respect to the controls. Primary hum an respiratory epithelial cells cultured on the hydrogel showed proper atta chment, normal morphology, and growth. A small proportion of cells on the h ydrogel showed synchronously beating cilia. RT-PCR analysis showed that cel ls on the hydrogel expressed mucins 2 and 5 and cytokeratin 13, which are m arkers for secretory goblet and squamous cells, respectively. All these res ults demonstrate that the hydrogel supports the growth of a mixed populatio n of differentiated epithelial cells. This hydrogel is suitable as a cultur e substratum for respiratory epithelial cells and could be used as a potent ial candidate for coating tracheal prostheses. (C) 2001 John Wiley & Sons, Inc.