Effect of fibroblasts on epithelial regeneration on the surface of a bioengineered trachea

Objectives: Our group applied a tracheal prosthesis, which was composed of polypropylene as the frame and collagenous sponge as the scaffold, to the first human case and had successful results. The objective of this study was to find a way to acquire more rapid re-epithelialization with fibroblasts on this tracheal prosthesis. Methods: Tracheal epithelial cells, which were isolated from the trachea of rats, were suspended in a collagenous gel. The collagenous gel with fibroblasts was layered on a collagenous sponge. The grafts of this "bioengineered trachea" were implanted into tracheal defects of rats, and the regenerated epithelium on the grafts was histologically examined. Results: Seven days after implantation, stratified squamous epithelium covered almost all of the surface of the gel, and some of the implanted fibroblasts in the gel were lined up just below the epithelium. Fourteen days after implantation, columnar and cuboidal ciliated epithelium covered almost all of the surface of the defects, and the implanted fibroblasts had disappeared. The numbers of regenerated epithelial cells at 14 days after implantation were larger than those of control models without fibroblasts, with statistical significance. Conclusions: The results suggested that the grafts of bioengineered trachea composed of collagenous sponge and collagenous gel with tracheal fibroblasts accelerated epithelial differentiation and proliferation in vivo.