Urothelial cell transplantation using biodegradable synthetic scaffolds

Reconstruction of the urinary bladder with bowel to restore storage capacity is associated with significant complications arising from substituting an absorptive, mucus-producing intestinal epithelium for the barrier urothelium of the bladder. To overcome these problems, we are developing a "composite enterocystoplasty" procedure to replace the epithelium of the bowel with autologous in vitro-propagated normal urothelial cells. The aims of this study were to evaluate synthetic biomaterials as delivery vehicles for the cultured urothelial cells and provide support during transfer and cell adherence to the de-epithelialized bowel wall. The surgical compliance of 12 biomaterials was evaluated, along with their ability to support urothelial cell attachment. Transfer of urothelial cells onto biomaterials as single cell suspensions or intact cell sheets was investigated. Seeding of a single cell suspension on to non-woven mesh resulted in poor cell attachment. Seeding onto woven mesh was more efficient, but the most effective transfer method involved producing an intact cell sheet that could be combined with woven, knitted and non-woven biomaterials. Transfer of the cell sheet : mesh complexes onto a de-epithelialized bladder stroma produced a stratified epithelium incorporating the strands of the mesh and expressing urothelial-associated antigens after 48 h in organ culture. Thus, we have developed and evaluated a suitable transfer method for in vitro propagated urothelial cells to be used in "composite enterocystoplasty".