Autologous micrografting improves regeneration of tissue-engineered urinary conduits in vivo

Urogenital reconstructive malformation surgery is sometimes hampered by lack of tissue for the repair. We have previously shown that autologous micrografting allows for single-staged scaffold cellularization after surgical implantation. Here, a collagen-based scaffold reinforced with biodegradable mesh and a stent was implanted as a bladder conduit in ten full-grown female minipigs. We aimed to assess short-term regenerative outcomes, safety, and feasibility of implanting tubular urinary micrografted scaffolds versus acellular controls. Five scaffolds were embedded with autologous urothelial micrografts harvested perioperatively. After six weeks, all animals were assessed by cystoscopy, CT-urography, and microanatomical assessment of the urinary conduits. The procedure proved technically feasible within the confines of a regular surgical theater, with duration-times comparable to corresponding conventional procedures. No animals experienced postoperative complications, and all implanted conduits were patent at follow-up. Improved tissue regeneration was observed in the micrografted conduits compared with the acellular controls, including increased luminal epithelialization, increased cell proliferation, decreased cell apoptosis, and increased conduit vascularization. We concluded that single-staged on-site construction and implantation of tissue engineered urinary conduits proved feasible and safe, with improved regenerative potentials in micrografted conduits. This study presents a new approach to urinary conduits, and merits further investigations for advancement towards clinical translation.