Construction and evaluation of urinary bladder bioreactor for urologic tissue-engineering purposes

Objective: To design and construct a urinary bladder bioreactor for urologic tissue-engineering purposes and to compare the viability and proliferative activity of cell-seeded extracellular matrix scaffolds cultured in the bioreactor with conventional static growth conditions. Materials and Methods: A urinary bladder bioreactor was designed and constructed to replicate physiologic bladder dynamics. The bioreactor mimicked the filling pressures of the human bladder by way of a cyclical low-delivery pressure regulator. In addition, cell growth was evaluated by culturing human urothelial cells (UCs) on porcine extracellular matrix scaffolds in the bioreactor and in static growth conditions for 5 consecutive days. The attachment, viability, and proliferative potential were assessed and compared with quantitative viability indicators and by fluorescent markers for intracellular esterase activity and plasma membrane integrity. Scaffold integrity was characterized with scanning electron microscopy and 4′,6-diamidino-2-phenylindole staining. Results: No significant difference in cell viability was identified between both experimental groups after 3 days of culture (P =.06). By day 4, the number of viable UCs was significantly greater in the bioreactor compared with the number cultured under static conditions (P =.009). A significant difference in UC viability was also present after 5 days of culture between the bioreactor and static group (P =.006). Viability/cytotoxicity assays performed on day 5 also confirmed the viability of UCs in both experimental groups. Conclusion: Significantly greater UC growth occurred on the extracellular matrix scaffolds cultured in the bioreactor compared with conventional static laboratory conditions after 3 days of culture. Our initial bioreactor prototype might be helpful for permitting additional advances in urinary bladder bioreactor technology.