Tissue-engineered cholecyst-derived extracellular matrix: a biomaterial for in vivo autologous bladder muscular wall regeneration

To compare the biocompatibility and histological aspects of cholecyst-derived extra cellular matrix (CDECM) graft, either alone or with application of autologous detrusor muscles small fragments (ADMSF) on rabbit bladder mucosa for bladder augmentation. The gallbladders were acellularized and evaluated for preserved acellular matrix scaffold and biophysical properties. Thirty rabbits were divided into five groups. Rabbits in the control group underwent partial detrusorectomy followed by perivesical fat coverage. Groups I and II underwent the same procedure and bladder mucosa was covered either by acellular rabbit gallbladder (ARG) (group I) or acellular sheep gallbladder (ASG) (group II). Groups III and IV underwent detrusorectomy and the bladder mucosal was seeded by ADMSF and covered by ARG (group III), or ASG (group IV). Biopsies were taken at 4, 12, and 24 weeks postoperatively. Higher expression of CD34 endothelial progenitor cells, CD31 microvessels, alpha-smooth muscle actin, S100, and cytokeratin with more organized muscular wall generation was demonstrated in groups III and IV. Expression of IHC markers was higher in groups III and IV compared with groups I and II in all the time points. The current study confirmed that autologous fragment-seeded CDECM can be considered as a reliable natural collagen scaffold for bladder augmentation.