Jejunoileal bypass changes the duodenal cholecystokinin and somatostatin cell density

BACKGROUND: In obese patients, jejunoileal bypass (JIB) has been used to induce weight reduction. Changes in the neuroendocrine system may be affected by the JIB-operation, because the proximal small intestinal mucosa has a rich supply of endocrine cells and peptidergic nerves.

MATERIALS AND METHODS: In 37 obese patients operated with JIB 1-30 years ago, small intestinal biopsies were taken at the duodeno-jejunal flexure, proximal to the anastomosis and from 5 unoperated obese persons and 20 normal weight patients. The tissue specimens were processed for immunocytochemical demonstration of cells/nerves containing: gastrin, cholecystokinin (CCK), secretin, gastric inhibitory peptide (GIP), motilin, somatostatin, serotonin, glicentine, peptide YY (PYY), neurotensin, vasoactive intestinal peptide (VIP), substance P, neuropeptide Y (NPY) and galanin. The number of different endocrine cell-types were counted per unit length of mucosa, and the density of the peptidergic nerves was assessed semiquantitatively according to a schematic scale.

RESULTS: JIB-patients had an increased density of CCK and somatostatin cells in the duodenal mucosa. The CCK cells displayed a changed reaction pattern, with a greater cell number reacting with an antiserum directed towards a non-amidated mid-sequence of procholecystokinin compared with the other groups. In obese unoperated patients, the density of PYY and secretin cells was decreased compared with the JIB-patients and the density of the GIP cells compared with both other groups.

CONCLUSION: JIB induces an up-regulation of somatostatin and CCK precursor-containing cells in the duodenal mucosa. The time duration after the JIB did not seem to influence the results.