Objective: To investigate the presence of tight junction (TJ) changes of the intestinal mucosa, and elucidate the possible mechanism for changes in bowel evacuation in patients with irritable bowel syndrome (IBS).
Methods: In 10 normal control subjects, 10 patients with constipation predominant IBS (C-IBS) and 10 with diarrhea predominant IBS (D-IBS), biopsies were taken from the terminal ileum and ascending colon. Lanthanum nitrate tracing electron microscope and cytochemical technique were employed to observe TJ changes in the intestinal mucosa.
Results: Like the control subjects, C-IBS patients had normal TJ structure in the intestinal mucosa, whereas D-IBS patients exhibited some abnormalities in TJ structure either in their terminal ileum (7 in 10) or ascending colon (8 in 10), revealed by TJ gap widening with lanthanum nitrate extravasation into the surrounding tissue. Such changes were also observed in 3 of the 4 patients with a history of acute infectious diarrhea.
Conclusion: The changes in the intestinal mucosal TJ structure and function might contribute to altered bowel evacuation in patients with irritable bowel syndrome.