Objective To determine the decreased antigenicity of the capacity were higher in the hamster BAMG-grafted animals, whereas in vitro contractility and compliance bladder acellular matrix graft (BAMG) through xenotransplantation and to assess the in vivo and in vitro were best in the dog BAMG-regenerated bladders. All grafted bladders had significantly better capacity and functional properties of the rat urinary bladder thus regenerated.compliance than the autoregenerated bladders after partial cystectomy alone. Materials and methods After partial cystectomy (>50%), BAMGs prepared from hamster, rabbit and Conclusions The present in vivo and in vitro studies show that BAMG-augmentation cystoplasty can lead to mor-dog urinary bladders were grafted to male and female Sprague-Dawley rats; 10 control rats underwent par-phological and functional regeneration of the rat bladder, preserving its low-pressure reservoir function. tial cystectomy only. Urinary storage and voiding function were monitored in 15 animals using a Because BAMG-regenerated bladders show functional innervation that is similar to normal bladders, they specially designed 'micturition cage' and cystometry. After 4 months, organ-bath studies and histological can work in coordination with the host bladder components, thus generating adequate intravesical pressure techniques were used to evaluate bladder regeneration in vitro in the grafted animals.to produce sustained voiding. The decreased antigenicity makes heterologous BAMG transplants feas-Results Clinically relevant antigenicity was not evident; no animal died from rejection and all bladder wall ible without immunosuppression.