Augmentation cystoplasty using decellularized vermiform appendix in rabbit model

PurposeThe aim of this study was to produce a decellularized rabbit vermiform appendix (sacculus rotundus) and investigate its feasibility in bladder augmentation or appendicovesicostomy. The superiority of sacculus rotundus over other tissues is its unique mechanical properties as well as its abundant collagen content.Materials and methodsThe acellular matrix of vermiform appendix underwent different laboratory investigations prior to transplantation. We divided 12 rabbits into 3 groups: group I underwent bladder augmentation cystoplasty by detubularized acellular matrix. Group II underwent implantation of the tapered (tubularized) acellular matrix just beneath the seromuscular part of the bladder without connection to the bladder urothelium. Group III underwent the same procedure as group II plus reimplantation of tapered and tubularized acellular matrix (simulating an appendicovesicostomy). The distal end of the transplanted graft was connected to the bladder mucosal opening and was intubated by a 5 Fr double blind ended feeding tube catheter. Biopsies were taken 3, 12, and 36 months post-operatively for further histological and immunohistochemical analyses.ResultsThe results of the examinations performed prior to transplantation, revealed a decellularized structure resembling the native tissue with intact extracellular matrix, normal pits and appropriate gaps that will be suitable for further cell seeding. Histopathology examination of the biopsies after transplantations confirmed successful cell seeding with urothelial lining in groups I and III, while the inner lumen in group II showed no urothelial lining.ConclusionThe results suggest that we can prospect to perform bladder reconstruction by the application of this method without complications of previously reported augmentation cystoplasty. In the current study we used the bladder as a natural bioreactor for autologous recellularization which may pave the road for clinical application in acellular matrix augmentation cystoplasty.