Transplantation of infantile bladder in rats - An alternative procedure for bladder augmentation

Background, Our purpose was to evaluate whether bladder transplantation (BT x) can be used for bladder augmentation (BA), Methods, Bladders from infantile Brown-Norway rats (less than 21 days old) were excised and each transplanted into a pouch created in the distal oment um of a B-week-old Lewis rat (fully allogeneic BTx). No immunosuppressant w as used in group I (n=12), Intramuscular FK506 was used daily from the day of BTk in group II (n=16; 0.2 mg/kg), group III (n=22; 0.6 mg/kg), and grou p TV (n=16; 1.2 mg/kg) until harvesting 3, 4, 5, or 6 weeks after BTx, FK50 6 was used for only 2 weeks in group V (n=12; 0.6 mg/kg/day) and group VI ( n=12; 1.2 mg/kg/day). Syngeneic bladder transplants acted as controls (n=16 ), Hematoxylin and eosin staining was used to examine all grafts, In six ra ts from group III, BA was performed by anastomosing the graft to the recipi ent bladder 10 days after BTx, Results. Each successfully transplanted graft appeared macroscopically as a thin-walled cyst. Rejection was seen in all grafts from groups I, II, V, a nd VI, and was minimal or absent in groups III and TV. On medium to long-te rm follow-up the only side effect of FK506 observed was reduced weight gain . Graft survival in the control group was 100%. BA was successful in all si x cases, and the mucosa was normal throughout each augmented bladder. Conclusions, This is the first report of the successful transplantation of infantile tissue without vascular anastomosis. Because of the efficient, sa fe immunosuppression possible with FK506, our BTx technique could find clin ical application for creating viable vesical tissue that could be used for BA.