Urinary bladder reconstruction using autologous collagenous connective tissue membrane “Biosheet” induced by in-body tissue architecture

Abstract

Background: Tissue engineering technology has the potential for bladder reconstruction without complications. We have previously developed autologous collagenous prosthetic tissues using in-body tissue architecture (iBTA). This is a cell-free tissue engineering technology that can produce autologous implantable tissues be a desired shape by simple subcutaneous embedding of a specially designed mold. Grafts formed by iBTA can be made in any shape and form, including sheet-shaped tissues (Biosheet). In this study, we evaluated the efficacy and safety of autologous Biosheet as bladder repair material in a canine bladder defect model. Methods: We studied four healthy adult beagles (1-2 years old, 9.3-9.9 kg). Autologous Biosheets were prepared by embedding specially designed molds into subcutaneous pouches in the beagles. Eight weeks after implantation, the molds were extracted, and collagenous connective tissues surrounding the molds were harvested as autologous Biosheet. The urinary bladder wall was excised (2 cm × 2 cm) and autologous Biosheets were sutured to the cut edge of the native bladder using a simple continuous suture pattern. The efficacy of implantation of the Biosheets was evaluated by physical examination, blood tests, abdominal ultrasound, urinalysis, and urography, at 0, 1, 3, 7, 14, 28, 56, and 84 days after the implantation. The Biosheets were extracted at 28 days (n=1) and 84 days (n=3) after implantation. Results: No side-effects were observed during follow-up. No disruption of the sheet or any urinary leakage into the peritoneal cavity was observed. Histological analysis revealed α-SMA-positive muscle fibers at the margin of the Biosheets, indicating regeneration of the urinary bladder tissue. Conclusion: This is the first report evaluating the efficacy and safety of iBTA-induced autologous “Biosheets” as a bladder repair material in a canine model. In summary, autologous Biosheets could be useful biomaterials for urological reconstruction.