Effectiveness of denuding the intestinal mucosa by submucosal injection in the porcine model

Purpose: Lack of mucosal regrowth on denuded bowel segments is considered a pre-requisite for successful grafting of cultured urothelial cells for bladder augmentation. This study was designed to establish a technique for clean and complete de-epithelialization of the intestinal mucosa. Materials and Methods: A segment of the small bowel was isolated in six microminipigs. The isolated segment was detubularized and the submucosa injected with HEPES-buffered saline, elevating the mucosa from the underlying tissue and allowing removal with ease. One portion was resected and, along with a portion of the removed mucosa and a sample of the full-thickness bowel, submitted for histologic evaluation. Another portion of the bowel segment remained denuded while the final denuded segment was covered with polyglactin mesh. After 3 days, 1 week, and 3 weeks, specimens from each of the bowel segments were collected for histologic assessment. Immunoperoxidase labeling was performed to confirm the presence or absence of mucosal regrowth. Results: All intestinal segments showed no mucosal regrowth at the 3-day, 1-week, and 3-week incubation periods. Minimal reaction between the denuded bowel segment and the mesh was evident in all of the pigs. Conclusions: In the porcine model, intestinal mucosa can be removed completely using submucosal injection. This technique may be useful in future clinical studies involving bladder augmentation using denuded bowel.