Bladder reconstruction using a prevascularized capsular tissue seeded withurothelial cells

Purpose: Recent advances in cell biology and tissue engineering have involv ed various avascular or acellular scaffolds with or without seeded cells. T hese techniques are frequently complicated by tissue necrosis, contracture and resorption. We used a vascularized matrix prelaminated with autologous cultured urothelial cells to reconstruct bladder wall defects. Materials and Methods: A silicone block inserted into the right groin of 50 male Wistar rats directly superficial to the inferior epigastric vessels w as used to induce capsule pouch formation. Urothelial cells harvested simul taneously and cultured mere then suspended in fibrin glue and seeded into t he newly formed capsule after removing the silicone block. After 1 week the prelaminated nap was transposed into a surgically created bladder wall def ect. Experimental groups included rats with a urothelial cell seeded capsul e pouch sacrificed at 1 and 4 weeks, respectively, after bladder reconstruc tion. In control rats scaffolds were treated only with fibrin glue or salin e before transposition. Results: Hematoxylin and eosin and immunohistochemical staining showed a co ntinuous multilayered urothelial Lining along the transposed prelaminated c apsule flap in the experimental groups with better survival compared to con trols treated only with fibrin glue (80% mortality) or saline (100% mortali ty). The surviving 3 control animals did not have a urothelial lining. Conclusions: Vascularized prefabricated flaps lined with culture derived ur othelial cells were successfully used for bladder reconstruction in a rat m odel. The technique of prefabricating a vascularized scaffold lined with au tologous urothelial cells may provide a method for future reconstruction of the genitourinary systems.