RESUMO
PURPOSE: We evaluated the usefulness of biosheet, an in-body tissue-engineered collagenous membrane, as a novel repair material for abdominal wall defects in a beagle model. METHODS: Biosheets were prepared by embedding molds into subcutaneous pouches in two beagle dogs for 2 months, with subsequent storage in 70% ethanol. The obtained biosheets (thickness 0.5 mm, size 25 cm2) were implanted to replace same-size defects in the abdominal wall of two beagles in an allogenic manner. RESULTS: The biosheets were not stressed during suturing and did not split; moreover, patch implantation into the defective wound was easy. No complications such as anastomotic leaks or infections occurred during implantation. One year post-implantation, the thickness of the biosheet implantation section increased to approximately 2.5 mm, corresponding to approximately 70% of the native abdominal wall. A section of the abdominal wall muscle elongated from the periphery of the newly formed collagen layer, and the peritoneum was entirely formed on the peritoneal cavity surface, resulting in partial regeneration of the three-layered abdominal wall. The mechanical strength of the newly formed wall was approximately fivefold higher than the native wall. The elasticity of the biosheet in the low-strain region decreased to approximately 10% post-implantation, similar to the native wall. CONCLUSIONS: This pilot study demonstrated that biosheet maintained the abdominal wall without any complications for 1 year post-implantation, and partial regeneration was observed. Although this experiment was limited to two cases, the results indicated that biosheet may serve as a reliable abdominal wall restorative material.
