Novel tubular constructs for urinary diversion: a biocompatibility study in pigs

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The use of bowel tissue for urinary diversion can be associated with severe complications, and regenerative medicine may circumvent this by providing an engineered conduit. In this study, a novel tubular construct was identified for this purpose. Three constructs (diameter 15 mm) were prepared from type I collagen and either (a) a semi-biodegradable Vypro II polymer (COL-Vypro), (b) a rapidly biodegradable Vicryl polymer (COL-Vicryl) or (c) an additional collagenous layer (COL-DUAL). After freezing, lyophilization and crosslinking, all constructs showed a porous structure with a two-fold higher strength for the polymer-containing constructs. These constructs were connected to full bladder defects of 11 female pigs and evaluated after 1 (n = 4) or 3 months (n = 5). With respect to surgical handling, the polymer-containing constructs were superior. All pigs voided normally without leakage and the survival rate was 82%. For the implanted COL-Vypro constructs (8/9), stone formation was observed. COL-DUAL and COL-Vicryl showed better biocompatibility and only small remnants were found 1 month post-implantation. Histological and immunohistochemical analysis showed the best regeneration for COL-Vicryl with respect to urothelium; muscle pedicles and elastin formation were best developed in the COL-Vicryl constructs. In this study, COL-Vicryl constructs were superior in both biocompatibility and bladder tissue regeneration and have high potential for artificial urinary diversions. Copyright (c) 2016 John Wiley & Sons, Ltd.