Segmental intestinal transplantation in rats with resected entire small bowel, ileocecal valve, and cecum.

Segmental intestinal transplantation was studied in a rat model of severe short gut syndrome across major histoincompatibility barriers. Lewis (RT1l) recipient rats whose entire small bowel (approximately 80 cm), ileocecal valve, and cecum were resected and who had no transplant, uniformly died of malabsorption on Day 9.8 +/- 0.4 (n = 11). Without cyclosporine, allograft recipients (n = 2), died of rejection on Days 8 and 10. Recipient animals with 20-cm jejunum and 40-cm jejunal transplants from Buffalo (RT1b) rats and treated daily with cyclosporine (5 mg/kg/day) intramuscularly (Days 0-28) and vitamin B12 (every other week) enjoyed significantly prolonged survival to Day 58.2 +/- 13.7, P less than 0.003, n = 10, and Day 129.1 +/- 7.4, P less than 0.001, n = 10, respectively. While 7 of 10 rats in the 20-cm jejunal transplant group died of malabsorption between Days 14 and 58, none of 10 animals in the 40-cm jejunal transplant group died of this complication. Four of 10 rats in the 40-cm jejunal transplant group thrived at 150 days after the operation, at which time they were sacrificed. Morphologically, the grafts demonstrated hypertrophic changes. The data from this study suggest that intestinal allografts have pronounced intestinal adaptative characteristics. Using segmental jejunal grafts, intestinal transplantation is an effective surgical modality for the short gut syndrome in the rat.