Small bowel rejection in isolated small bowel transplantation and in multivisceral transplantation: A comparative study in a large animal model

The proposition that a combined graft including the liver protects other organ allografts from the same donor is well known. However, it is not evident in the clinical results. The present experiments were undertaken to compare acute small bowel rejection in isolated small bowel transplantation with multivisceral transplantation. Using 36 outbred male Large-White pigs, isolated small bowel transplantation (SBTX: n=9) and abdominal multivisceral transplantation (MVTX: n=9) were performed without immunosuppression. The survival rate and blood serum samples were monitored postoperatively. In order to compare acute small bowel rejection, sequential biopsy specimens from Thiry-Vella loops were also monitored daily beginning on me 3rd day after transplantation. The specimens were scored from 0 to 3 according to the severity of the rejection. The survival rate was not significantly different However, significant differences were noted in the cause of the death and in the pathologic changes of the small bowel. In contrast to SBTX, the small bowel rejection of MVTX was significantly delayed and less severe. The rejection score of MVTX was significantly better than SBTX from 5 postoperative days (POD) to 1 lPOD (P<0.05). The present study demonstrated mat acute small bowel rejection of MVTX graft including the liver was delayed and less severe than that of SBTX in an outbred large animal model.