Bladder reconstruction using a prevascularized capsular tissue seeded with urothelial cells

Recent advances in cell biology and tissue engineering have involved various avascular or acellular scaffolds with or without seeded cells. These 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.

A silicone block inserted into the right groin of 50 male Wistar rats directly superficial to the inferior epigastric vessels was used to induce capsule pouch formation. Urothelial cells harvested simultaneously and cultured were then suspended in fibrin glue and seeded into the newly formed capsule after removing the silicone block. After 1 week the prelaminated flap was transposed into a surgically created bladder wall defect. Experimental groups included rats with a urothelial cell seeded capsule pouch sacrificed at 1 and 4 weeks, respectively, after bladder reconstruction. In control rats scaffolds were treated only with fibrin glue or saline before transposition.

Hematoxylin and eosin and immunohistochemical staining showed a continuous multilayered urothelial lining along the transposed prelaminated capsule flap in the experimental groups with better survival compared to controls treated only with fibrin glue (80% mortality) or saline (100% mortality). The surviving 3 control animals did not have a urothelial lining.

Vascularized prefabricated flaps lined with culture derived urothelial cells were successfully used for bladder reconstruction in a rat model. The technique of prefabricating a vascularized scaffold lined with autologous urothelial cells may provide a method for future reconstruction of the genitourinary systems.