Feasibility of Pulmonary Airway Tissue Engineering and Repair Using a Cell Spraying Device and Decellularized Porcine Trachea

Abstract

Methods for tracheal repair and regeneration are necessary due to the limitations of tracheal resection and reconstruction for certain disorders such as tracheal stenosis, tracheomalacia, and tracheal tumors. Additionally, pulmonary injuries such as airway burns do not have effective treatment options aside from supportive care. The feasibility of a cell spraying device is investigated here as a system for applying human bronchial epithelial cells (HBECs) to decellularized porcine trachea matrices for creation of engineered grafts or as a minimally invasive method for delivering cells for wound healing. HBECs show viability greater than 90% after spraying onto cell culture media or tissue culture plastic. Similarly, one day after spraying onto decellularized trachea, viabilities are seen to be around 90%. Around day three, viabilities were slightly decreased to around 80%. After culturing for over one week, HBECs sprayed onto decellularized trachea displayed a basal cell marker (cytokeratin-5, CK5) and a club cell marker (uteroglobin). Markers for ciliated cells and goblet cells that are crucial for tracheal epithelium could not be found, but this needs to be investigated further. To validate the mechanical performance of the decellularized trachea, compressive resistance testing was performed before and after decellularization of tracheal rings. Results were generally inconclusive with high degrees of variability. A paired sample test conducted with 4 tracheas provided the most interesting results and showed that the decellularization process produced a significantly different compressive resistance compared to the native samples. In practice though this did not seem to be noticeable as the variability found within tracheal samples masked the difference. This would suggest that the decellularization process is not detrimental to the compressive resistance of trachea rings. Based on the results reported here, using a cell spraying device for engineering tracheal grafts and airway epithelial repair seems achievable.