EXPERIMENTAL IN-VITRO AND IN-VIVO STUDIES OF EPITHELIUM FORMATION ON BIOMATERIALS SEEDED WITH ISOLATED RESPIRATORY CELLS

Extensive tracheal defects after intensive care medicine, trauma, or l arge resections in tumor surgery remain a major challenge in plastic a nd reconstructive surgery. Defects that cannot be satisfactorily treat ed by complicated and costly reconstructive techniques reveal a need f or an alloplastic tracheal replacement. Recent experimental and clinic al studies in the development of alloplastic tracheal prostheses prove d that the lack of an epithelial lining on the luminal surfaces and in adequate biophysical properties and shapes of the prostheses were the main causes for failure of these prostheses. In this study a cell-seed ing technique has been used. Adhesion, spreading, and differentiation of seeded mucosa cells on biomaterials in vitro were observed by scann ing election microscopy (SEM). Chemical properties and surface structu re of the material influenced the differentiation process. Epithelium formation of incorporated tracheal prostheses was tested in animal exp eriments. Isolated respiratory cells were seeded into implanted tubula r prostheses of porous polyurethane or expanded polytetrafluorethylene . Light microscopy and SEM showed the tendency of epithelium formation on the surface of the lumen. Vigorous cell layers, predominantly as m ultiple cell layers of squamous epithelium, were observed. Ciliated or mucus cells were not detected. It can be stated that the epithelium f ormation on incorporated porous implants is possible. Further studies of the stability and the differentiation process of the epithelium on such implants is needed before an introduction of tracheal replacement s into the clinical practice can be considered.