Long-term bladder regeneration has not been successful instead of augmentation with gastrointestinal segments, as is commonly performed for bladder reconstruction. To evaluate whether or not cell-seeded bioabsorbable materials regenerate half-resected bladder in a rabbit model. Female Japanese white rabbits were divided two groups: cell-seeded material (CSM) group and Control (n = 6 each). Control rabbits underwent resection of half the bladder. CSM rabbits were sutured with cell-seeded amniotic membrane and P(LA/CL) material after bladder resection. After 6, 12, and 18 months, rabbits underwent X-ray and cystometry, and bladder tissues after 18 months were subjected to functional and histological analyses. X-ray confirmed the peristaltic movements of the reconstructed bladders in the CSM group. On cystometry, the mean maximum bladder volume, maximum bladder pressure, and 25 mL bladder volume compliance in the CSM group were significantly greater than in the Control group at 6, 12, and 18 months. In addition, organ bath studies showed good contraction under electrical stimulation with increasing stimulation frequency in the CSM group, while, the Control group showed weak contraction on both tests in the central marginal zone. Furthermore, the rates of neovascularization, urothelial and smooth muscle formation, and neurofilamentation in the CSM group were significantly greater than in the Control group. Oral mucosal cell-seeded amniotic membrane and stomach smooth muscle cell-seeded P(LA/CL) scaffold with omentum after abdominal implantation regenerated functional bladder with satisfactory epithelium and smooth muscle without scarring more than 1 year. Impact Statement Regeneration of functional bladder without using gastrointestinal segments has been a huge challenge to urological reconstruction. Various materials, such as nonbioabsorbable materials and biomaterials have been attempted to reconstruct bladder in animal models. However, the long-term results more than a year failed due to the low biocompatibility, high risks, and difficulty creating the materials. In this study, we revealed long-term bladder regeneration using cell-seeded amniotic membrane and P(LA/CL) material in a rabbit model. The new method of bladder reconstruction seems able to regenerate functional bladder with satisfactory bladder epithelium and bladder smooth muscle function without scarring for more than 1 year successfully.
Keywords: amniotic membrane; bladder regeneration; half-resected bladder model; poly-lactic acid and poly-caprolactone.