An experimental technique to assess the immunologic consequences of segmental small bowel transplantation

The amount of native small bowel required for adequate nutrition is variable, but lies between 10% and 20% of full length. Currently, for patients requiring small bowel transplantation (SBT), standard practice is to transplant the entire small bowel if space permits. Few experimental studies have addressed the effect of the length of small bowel transplanted on immune responses and in those that have, the amount of mesenteric lymph node (MLN) transplanted has always been a potential confounding factor, as have differences between jejunum and ileum.

Full-length and segmental heterotopic rat SBT was performed between PVG donor and DA recipients. To transplant reduced length small bowel grafts but to exclude immunologic differences between jejunum and ileum, equal lengths of bowel were resected from proximal and distal ends in the donor. A proportional amount of MLN was carefully dissected using a microvascular technique and then excised. Serial serum samples from the transplant recipients were tested for anti-PVG (rejection) and anti-DA (graft-versus-host) antibodies using a two-color flow cytometric technique, described previously, with the aim of looking for differences in immunologic responses to full and segmental grafts.

We have established a model of segmental SBT that includes a proportional amount of MLN and is free from differences between jejunum and ileum. Preliminary data have demonstrated the development of circulating anti-host and anti-graft antibodies with time for both full-length and segmental SBT.