Mast cell mediated ion transport in intestine from patients withand without inflammatory bowel disease

摘要

Background—Mast cells have been shown to regulate intestinal ion transport in animal models and normal human colon but their physiological role in human intestinal inflammatory disorders is unknown.
Aims—To examine mast cell regulation of ion transport in inflammatory bowel disease (IBD).
Subjects and methods—Small and large intestine was obtained from patients with and without IBD undergoing surgical resection. Short circuit current (Isc) responses to rabbit antihuman IgE, histamine, and electrical stimulation were measured in Ussing chambers. Specimens were also examined for mast cell numbers and degree of inflammation.
Results—Isc responses to anti-IgE and histamine were smaller in magnitude in IBD compared with non-IBD tissues. In all tissues, anti-IgE Isc responses were reduced by about 80% in chloride free buffer. The histamine H1 receptor antagonist, pyrilamine, decreased anti-IgE responses in non-IBD tissues. Greater inhibition with pyrilamine was seen in IBD small intestine but its effect was less in IBD colon. Histamine pretreatment of non-IBD control tissues reduced anti-IgE responses to levels seen in IBD colon but had no effect in small intestine. Mast cell numbers were greater in IBD compared with non-IBDsmall intestine while no differences were observed between the colonicgroups. Isc responses to anti-IgE were not correlated withthe degree of mucosal inflammation.
Conclusions—This study provides further evidencethat mast cells are capable of mediating alterations of ion transportin human gut but that this regulatory role may be altered in IBD. Thedata suggest that prior activation of mast cells with release ofhistamine may account for the reduced secretory response to anti-IgEobserved in IBD colonic tissues.

Keywords:mast cells; intestine; ion transport; histamine; ulcerative colitis; Crohn's disease