Small bowel allografts maintained by administration of bombesin while under immunosuppression

Background/Purpose: The aim of this study was to determine if Bombesin (BBS) could help maintain the mucosal villus state in small bowel allografts without inducing acute rejection under immunosuppression. Methods: Allogeneic small bowel transplantation was performed heterotopically in rats (n = 12). All rats received daily administration of FK506 from postoperative day 0 to day 28. On postoperative day 14, rats were divided into 2 groups of 6 rats each, and administered BBS or normal saline as a control. After 2 weeks of treatment, the rats were killed, and the graft mucosal villus state was evaluated by Hamp ]E staining, and crypt cell proliferation analysis was performed using immunohistochemistry with proliferative cell nuclear antigen (PCNA). Results: Villi were thin, and villus blunting was marked in the control group. The BBS group showed that the villi of the grafts were well maintained, and the volume of the lamina propria mucosa was adequately preserved. The PCNA labeling index of crypt cells in the control group was 40.06 plusmn] 3.36 (mean plusmn] SD) and that in the BBS group was 61.02 plusmn] 4.27. There was a significant difference (P lt ] .001) between the 2 groups. Conclusions: BBS maintained allograft epithelial cells and the volume of the lamina propria intestinal mucosa, stimulating proliferation of crypt cells under immunosuppression without inducing acute rejection. J Pediatr Surg 38:83-87.