The first step of experimental study on hybrid trachea: use of cultured fibroblasts with artificial matrix

Anastomotic stenosis secondary to developing granulation tissue prevents an artificial trachea of non-porous type model from a safe practical use. Taira reported that a non-porous artificial trachea having soft ends for anastomosis works better in this regards apparently by cushioning mechanical stimulations repeatedly applied to the anastomotic rings than most models ever studied have done. We hypothesized that hybridization of soft anastomotic ends of nonporous artificial trachea may further prevent granulation tissue at the anastomoses hopefully by leading epithelial growth earlier onto the inner surface of graft's ends. The graft of our use was made of a 5-cm-long knitted dacron tube with inner coating with silicone rubber covering the entire length but for a 5 mm segment at each end. To date six mongrel dogs have been subjected to test this hypothesis. A piece of subcutaneous tissue was obtained from each dog and prepared for culture of fibroblasts in MEM. These fibroblasts were then suspended in 0.1% collagen with MEM in a container, in which a graft was placed for further culture. Following some 3 weeks of this preparation each graft was implanted to replace a 10-cartilage-ring-long defect of the mediastinal trachea of each donor dog. One dog is enjoying active life 11 months postop, and another 3 months. Four dogs died from anastomotic stenosis 2 to 3 months. Being encouraged by the fact that the anastomotic rings of the long term survivors show bronchoscopically patency more than 40% of cut surface area, and some portion with possible epithelialization without granulation, we will report our further results, along with histological study.