Pathological manifestations of enterochromaffin cells and mast cells in small intestinal mucosa of patients with irritable bowel syndrome

AIM:To investigate the distributions and numbers of enterochromaffin cells (EC) and mast cells (MC), and the functional status of EC in the small intestinal mucosa of patients with irritable bowel syndrome (IBS). METHODS: Eighteen constipation-predominant IBS patients (group A), 20 diarrhea predominant IBS patients (group B) and 20 healthy normal controls (group C) were selected as subjects according to Rome III criteria. They all underwent colonoscopies and small intestinal endoscopies, and their mucosa samples at the descending part of duodenum, proximal end of jejunum and terminal ileum were obtained in the meantime. Immunohistochemical methods were used to detect EC and MC. EC were also observed under electron microscope for their functional status. RESULTS: ① For each high power visual field, the numbers of EC in group A and B at the descending part of duodenum were 9.4±3.9 and 10.2±3.7 respectively, 6.7±2.6 and 6.2±2.4 at proximal end of jejunum, 2.7±1.4,3.2±1.9 at terminal ileum. Compared with those in group C (10.5±3.4,6.6±3.4,3.1±1.7 respectively), they did not have significant differences (P0.05). ② Observed under electron microscope, EC in group A and B at the descending part of duodenum were of more active functional status, compared with those at terminal ileum, which was similar to group C. ③ The numbers of MC in group A and B at terminal ileum were 38.7±9.4 and 35.8±5.5 respectively, which were significantly more than those in group C (29.8±4.4, P0.01). But the numbers of MC in group A and B at terminal ileum did not have significant differences (P0.05). The numbers of MC at the descending part of duodenum in group A and B were 19.6±4.7 and 18.5±6.3 respectively, 18.8±5.8 and 19.7±4.8 at proximal end of jejunum. Compared with those in group C (19.2±3.3,20.0±6.9 respectively), they did not have significant dif-ferences(P0.05). CONCLUSION: Enterochromaffin cells show no significant change in small intestinal mucosa and mast cells increase at terminal ileum in patients with IBS. The pathological changes of EC and MC in the small intestinal mucosa of the patients with constipation-predominant IBS are similar to those in ones with diarrhea-predominant IBS.