PELVIC ILEOANAL RESERVOIRS - A LECTIN HISTOCHEMICAL-STUDY

Pelvic ileo-anal reservoir (ileal pouch) formation is now a common sur gical approach to the management of long-standing inflammatory bowel d isease. The ileal mucosa in this new environment responds with changes in morphology and histochemical reactivity, as shown by conventional techniques. In this study, pre-pouch ileum and pouch ileal mucosa from 20 patients have been examined with a large panel of lectins using an avidin-biotin-peroxidase technique, with appropriate negative control s and sugar-inhibition studies. Changes were noted between pre-pouch i leum and the pouch mucosa which were complex, and no single alteration was seen in every case. Most variations related to saccharide sequenc es near the non-reducing termini of O- and N-linked glycans. Many of t hese were seen with lectins having requirements for terminal fucosyl r esidues, and to a lesser extent for galactosyl sequences, and were mos t obvious in the epithelium. Some of the changes occurred with such fr equency as to suggest a direct response to surgery, but many of the va riations were likely to be adaptive responses, possibly related to inf lammation or infection. The changes in glycans were largely additive a nd could not be explained as a consequence of the actions of bacterial glycosidases. These alterations suggest that reservoir mucosa undergo es an adaptive response to the new intraluminal environment, without f rank colonic metaplasia, and some changes occur to a greater degree in patients with pouchitis.