Whole Organ Decellularizationtrachea Scaffold Tissue Engineering for Whole Segment Tracheal Transplantation/Replacement

The trachea is critical for respiration and airway protection in humans. Ideal methods for the reconstruction of the tracheal structure and restoration of tracheal function have not yet been developed once the trachea has been damaged or removed. The main focus of our study is related to the scaffold engineering for the reconstruction of the trachea. Based on our previous findings, we have learned that: 1. The decellularization process of the larynx and the trachea is effective in the generation of laryngotracheal scaffolds. However, the cartilage part which provides the most structural supporting forces for the scaffold appears to be difficult to be completely decellularized. 2. Artificial biocompatible materials such as the PLLA were able to be used as an outer skeleton which provide a very high strength comparing to the native trachea. However there are still many questions remained unanswered: ♦ Is the use of artificial material based structural maintaining skeleton necessary? ♦ Is one decellularization process fits the soft tissue and the cartilage at the same time? ♦ Can there be a decellularization process that can remove the cartilage cells without damaging too much soft tissue structures? ♦ Even if the cartilage is not completely decellularized, will there be any problems after implantations? In this study we have tried to use a new decellularization method with the freeze-dry-sonication-SDS (FDSS) decellularization process and was able to wash our all the cellular components from the soft tissue portion of the tracheal. Although the cartilage decellularization process is not yet optimized and the result remained unsatisfactory, however we do observe that the effectiveness of this FDSS decellularization can be manipulated through the adjustments of cycle numbers and most importantly comparing to the existing decellularization protocols, the FDSS process is very efficient and time saving. A scaffold can be fabricated within a few days WITHOUT further disruption of the soft tissue structures. However, the optimal condition and the true value of this new process remained to be determined. It has been reported that due to low immunogenicity of the cartilage tissue, if eventually the cellular contents in the cartilage can only be partially washed away, it is still possible to implant the scaffold without serious rejection responses. Therefore we also tried to implant the trachea scaffold treated only with the FDSS process with an end-to-end anastomosis (implantation) model. Preliminarily 2 weeks after implantation the implanted trachea was able to maintain its original structure with no signs of necrosis or collapse. The purpose of this proposal is to evaluate the feasibility of while segment tracheal transplantation using our novel Freeze-Dry SDS Sonication (FDSS) decellularized tracheal scaffold using the rabbit animal model.