Structural associations between mast cells and enteric nerves in normal and inflamed human colon

Activation of lamina propria mast cells in vitro leads to stimulation of transepithelial chloride secretion in human colonic mucosae ]. Pharmacological studies indicated that mast cell-evoked secretion was amplified by the enteric nervous system. In this study we have examined mast cell numbers and structural associations between mast ceils and nerves in lamina propria from human colons obtained at time of surgical resection. As a control, we used the histologically normal margin from tissues resected for Solid tumours. Involved and uninvolved (margin) samples were obtained following resection for Crohn's disease and for ulcerative colitis. Mucosal mast cells were visualised using Alcian Blue stain and nerves identified by immunohistochemistry using antibodies raised against GAP-43. Semi-thin (7pM) sections were studied by stereology. Mast cells were counted and the number of mast ceils which appeared to be in contact with nerves was determined. Unpaired Student's t-tests were employed to compare control values with values from tissues which were obtained from patients with Crohn's disease and ulcerative colitis (*p < 0.05; **p < 0.01).