Correlation between food intolerance and colon mucosal mast cells and substance P in 27 patients with diarrhea predominant irritable bowel syndrome / 中华消化杂志

ABSTRACT

Objective To investigate the significance and possible mechanism of food intolerance in diarrhea-predominant irritable bowel syndrome (IBS-D).Methods Twenty-seven IBS-D patients matched the Rome Ⅲ criteria were selected as IBS-D group.Twenty-seven healthy individuals without gastrointestinal symptoms were assigned to control group.Food intolerance situation of two groups were analyzed with food intolerance status evaluation questionnaire,and detection of 14 food specific IgG antibody.The severity of IBS symptoms of IBS-D group were scored by IBS-symptom severity scale (SSS).Two pieces of mucosal tissues of both ileocecal junction and sigmoid colon were obtained under colonoscopy.The content of mucosal substance P (SP) was determined by immunohistochemistry.The quantity of mast cells were detected by Giemsa staining.Chi square test and Fisher exact probability method were performed for rate comparison between two groups.Measurement data were compared with t test and Mann-Whitney rank sum test.The correlation between IBS-SSS score and mast cells and the expression of SP positive cells were analyzed by Spearman rank correlation analysis.Results There was no statistically significant difference in positive rates of food specific IgG between two groups (x2 =3.085,P=0.389),however according to food intolerance status evaluation questionnaire,the incidence of food intolerance of IBS-D group was 44.4 ％ (12/27) which was higher than that of control group (14.8 ％,4/ 27),the difference was statistically (x2 =5.684,P=0.017).Food intolerance severity index of IBS-D group (median0(0,60)) was higher than that of control group (median0(0,0)),and the difference was statistically significant (U=239.50,P =0.007).In foods that may cause intolerance,the percentage of foods rich in fermentable oligosaccharides and monosaccharides,disaccharides and polyol (FODMAP) such as milk,noodles,soybeans was up to 71.4％ (30/42).The expression tates of SP positive cells in the mucosa of ileocecal junction and sigmoid colon of patients with IBS-D were higher than those of the control group (x2-20.735 and 22.071,both P＜0.01).The numbers of mast cell in the mucosa of ileocecal junction and sigmoid colonic of patients with IBS D (2.40 ± 1.04/high power field (HPF) and 2.35±1.11/HPF) were more than those of the control group (0.97 ± 0.70/HPF and 0.89 ± 0.72/HPF),and the difference was statistically significant (t=-5.850 and-5.629,both P＜0.01).The severity of bowel symptom of patients with IBS-D was moderately correlated with the number of mast cells in the mucosa of sigmoid colon (r=0.576,P=0.002),and was moderately correlated with the expression of SP positive cells (r=0.691,P＜0.01).Conclusions There may be relation ship among low-grade inflammation of intestinal mucosa,food intolerance and severity of intestinal symptoms in patients with IBS-D.