Bladder Augmentation Using Tissue-Engineered Autologous Oral Mucosal Epithelial Cell Sheets Grafted on Demucosalized Gastric Flaps

Background. At present, autologous intestinal segments are often used for bladder reconstruction. However, the gastrointestinal mucosa often causes various complications. Methods. Oral mucosal tissues were obtained from the buccal cavity of beagle dogs. Primary oral mucosal epithelial cells were cultured on temperature-responsive culture dishes with a mitomycin C-treated 3T3 feeder layer for 2 weeks. Cultured epithelial cells were harvested as contiguous sheets by reducing the temperature to 20 degrees C. The study consisted of three groups. In group 1, oral mucosal epithelial cell sheets were autografted on demucosalized gastric flaps. Next, the gastric flaps with the oral mucosal epithelial cell sheets were used for bladder reconstruction. Bladder reconstruction was once immediately and then 5 days after epithelial cell sheet grafting in groups 2 and 3, respectively. Three weeks after bladder reconstruction, the gastric flaps with the oral mucosal epithelial cell sheets were examined by immunohistology. Results. Flaps grafted with oral mucosal epithelial cell sheets showed epithelial regeneration in groups 1 and 3. Regenerated epithelia were stratified and similar to native oral mucosa. However, the regenerated epithelium was absent from the reconstructive segment, and urothelial ingrowth was observed in group 2. Macroscopically, all reconstructive segments showed contracture. Conclusions. We successfully performed a bladder reconstruction using oral mucosal epithelial cell sheet-grafted flaps that exhibited epithelial regeneration. Further study should consider shrinkage prevention.