Engineering a composite neotrachea in a rat model

BACKGROUND: Attempts to reconstruct the trachea have been largely unsuccessful because of its rigidity and opening to the outside environment. Materials that impart rigidity are usually alloplastic, so they cannot be exposed to the open environment without an unacceptably high risk of infection and rejection. The authors hypothesized that tissue engineering principles can be employed to construct a well-integrated neotrachea with rigid support and an epithelial lining to mimic the structure and function of the native trachea. METHODS: A 30-mm-long segment of polytetrafluoroethylene vascular graft with a diameter of 10 mm was lined with a fascial flap based on the superficial inferior epigastric artery with full-thickness skin grafts on its luminal surface. The composite unit was then buried under the abdominal skin of 20 rats and harvested 3 weeks later. Microfil and methylene blue dye were injected into the superficial inferior epigastric arteries and histologic analyses were performed to assess microcirculation and polytetrafluoroethylene-tissue integration. RESULTS: Two composite neotracheas experienced minor damage due to chewing by the rats, but all other neotracheas were viable and without infection. Injection studies demonstrated excellent circulation throughout the fascial flaps and skin grafts and across the polytetrafluoroethylene grafts to the overlying abdominal skin. Histologic analyses revealed abundant muscle-walled blood vessel ingrowth within the polytetrafluoroethylene grafts and all layers of the neotracheas with minimal inflammatory reactions. CONCLUSION: The authors successfully have engineered a well-integrated neotrachea in rats that possesses rigid support, an epithelial lining, and reliable coverage-the prerequisites for successful trachea reconstruction.