Changes in tight junction of intestinal mucosa in patients with irritable bowel syndrome: a study with tracing electron microscope / 南方医科大学学报

<p><b>OBJECTIVE</b>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).</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>The changes in the intestinal mucosal TJ structure and function might contribute to altered bowel evacuation in patients with irritable bowel syndrome.</p>

Changes of tight junction claudin-1,-3,-4 protein expression in the intestinal mucosa in patients with irritable bowel syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the changes of intestinal mucosal tight junction proteins claudin-1, -3, -4 in patients with irritable bowel syndrome (IBS), and elucidate its possible role in the bowel evacuation habit changes and formation in these patients.</p><p><b>METHODS</b>Western blotting was employed to determine tight junction protein claudin-1,-3,-4 levels in the intestinal mucosa of patients in the control group, diarrhea-predominant IBS (D-IBS) group and constipation-predominant IBS (C-IBS) group.</p><p><b>RESULTS</b>Compared with the control group, D-IBS patients showed significantly decreased claudin-1 protein levels in both the small intestinal and colonic mucosae (P<0.05), whereas C-IBS patients had significantly elevated claudin-1 protein levels (P<0.05). No significant difference was found in claudin-3 protein expression in the both small intestinal and colonic mucosae between the D-IBS group and the control group (P>0.05), but claudin-3 protein level was shown to increase significantly in C-IBS patients (P<0.05). Claudin-4 protein followed the same pattern of alteration as claudin-1.</p><p><b>CONCLUSION</b>Down-regulated claudin-1 and -4 expressions can be associated with bowel evacuation habit changes and formation in patients with D-IBS, but up-regulated claudin-1, -3 and -4 expressions may relate to such bowel changes in patients with C-IBS.</p>