Tracheal Tissue Engineering

Large airway defects pose a substantial problem to surgeons in both pediatric and adult\ud populations. For example, primary tracheal cancers can result in neoplastic lesions, which\ud are often not diagnosed until the tumor has become inoperable. These patients are palliated,\ud but have a poor prognosis, with only 5% survival after 5 years. Tissue engineered transplants\ud over a life saving new therapeutic option. Recent reports have demonstrated good midterm\ud results with decellularized human homograft tissue. However, these experiments have been\ud limited to compassionate use. To achieve effcacy necessary for more widespread use further\ud study is necessary to investigate alternate approaches and optimize the decellularization\ud technique. Additionally, clinical application of this technology will require translation to a\ud decellularized xenograft to obviate human tissue supply limitations. To this end, we compare\ud the use of 3 alternate detergents (SDS, Triton X-100, and CHAPS) to sodium deoxycholate\ud in the commonly accepted detergent enzymatic method (DEM). Fresh donor rat tracheas\ud were decellularized using a modified 9-day DEM protocol. The pre-implant scaffolds were\ud thoroughly characterized for each experimental group and implanted for 12 weeks using an\ud orthotopic rat tracheal reconstruction model. It was found that detergent choice strongly\ud affects the host remodeling response including host cell infiltration and epithelial differentiation.\ud The clinically relevant sodium deoxycholate and Triton X-100 groups were retested\ud with a final peracetic acid (PAA) rinse. It was determined that the use of PAA greatly\ud improved the in vivo response of the previously poor performing sodium deoxycholate and\ud made little improvement to the Triton X-100 scaffold. The optimum configuration, Triton\ud X-100 with a PAA rinse, was selected for translation to a clinically relevant porcine model. Porcine tracheal decellularization was achieved using a modified 14 day DEM protocol with a novel cyclical pressure approach. The suitability of these porcine tracheas for pre-clinical\ud large animal testing was verified through mechanical analysis (pressure-diameter and suture\ud retention) and in vitro seeding experiments with human bronchial epithelial cells