Urothelial Mesh - A New Technique of Cell Culture on Biomaterials

Introduction: Urogenital malformations, trauma or tumours may demand surgical reconstruction in children. Cell culture is an important technology in biomaterial research and tissue engineering. Tissue-engineering of urothelial organs is of interest in children, because the number of complications and re-operations may be reduced. Actually, monolayer cultures of urothelium are used for tissue engineering and biocompatibility testing. A culture system that more closely mimics the physiologic environment of the urothelium would be of interest. The aim of this study was to determine the biological and mechanical characteristics of urothelial mesh cultured in vitro. Methods: Meshes containing urothelium, lamina propria, and submucosal tissue were generated using a skin mesh graft cutter. Meshes were cultured in 6-well plates, on collagen I/III, polydioxanone/polylactic acid and silicone matrices. Cell morphology was examined by inversion microscopy, histology, and scanning electron microscopy. It was compared to urothelium cultured by methods reported in the literature. To define the basic mechanical properties, meshes were extended longitudinally by a servohydraulic testing machine and strain diagrams generated. Results: Urothelium was reproducibly cultured from meshes. Cell growth could be induced onto fibrillary collagen, polydioxanone-polylactic acid matrices and shaped polyurethane surfaces. Cells formed confluent layers of flat cells, resembling native urothelium. The meshes have unique mechanical properties, allowing for stable fixation, surgical handling and mechanical stimulation. Conclusions: Meshes can be used for cell culture on biomaterials. They maintain epithelial-stromal integrity and mechanic stability. The small size of tissue bridges allows in vitro culture for long periods with many potential advantages for tissue engineering and biologic research. Applications are possible both in vitro and in vivo.