Eighteen referred patients with D-IBS (eight females, 10 males aged 25–65 years; mean 42.6 years) and 15 healthy controls (five females, 10 males aged 31–57 years; mean 41.4 years) were included in the study. Median symptom duration was 65 months (range 7–360 months) and there was no statistical difference between the groups in terms of age or sex.
Mucosal mast cells were significantly increased in the terminal ileum, ascending colon and rectum of patients with IBS compared with controls (Fig. 1) ( Table 1 ). Moreover, the increase in the number of mast cells in one part of the colon was significantly related to that in the other part of colon (Fig. 2). Although significant differences in the mast cell infiltration were found between male and female controls, these sex-dependent differences were not observed for the IBS patients ( Table 1 ).
Immunoperoxidase staining of mast cells with AA1 in colonic mucosa of (a) predominant irritable bowel syndrome (IBS-D) patients and (b) control subjects (magnification ×400). Mucosal mast cells were significantly increased in the terminal ileum, ascending colon and rectum of patients with IBS compared with controls (P < 0.01, respectively).
Correlation of mucosal mast cell infiltration among the segments of the gut studied. The increase in mucosal mast cell count in the terminal ileum was significantly associated with that in the () ascending colon and () rectum (P < 0.01).
Infiltrations of plasma cells, lymphocytes, eosinophils and neutrophils were not different in IBS patients compared with controls for the terminal ileum, ascending colon, and rectum ( Table 2 ).
The rectal barostat test was performed on all 33 subjects (13 females, 20 males). All females subjects except two (who were postmenopausal) had a normal menstrual cycle and none described chronic gynecologic symptoms. Each female was studied during non-menses phases. As shown in Table 3 , the mean pressure values for the 'first sensation', 'sensation of urge to defecate' and 'maximal tolerable distension' steps in patients with IBS were significantly lower compared with those of the controls (P < 0.05, respectively). However, on multivariate analysis, including psychological traits, only the pressure of maximally tolerable distension (in other words, maximally tolerable pressure) proved to be a predictive factor of IBS, and the most efficient threshold of maximally tolerable pressure to identify IBS could be obtained at the distension level of 34 mmHg (sensitivity 62%, specificity 93%, positive predictive value 95%, negative predictive value 61%, accuracy 77%).
All patients with IBS complained of abdominal pain and the most frequently associated symptom was onset associated with a change in frequency of stool (83%). However, a significant correlation was not found between mast cell counts and symptoms of D-IBS.
Depression scores (BDI) and state of anxiety scores (STAI-S/T) were significantly higher in patients with IBS than in the controls (P < 0.05). Patients and controls with higher scores on the STAI-S/T and BDI showed a tendency towards increased mast cell counts at the terminal ileum, ascending colon, and rectum. However, this finding was not statistically significant (P > 0.05).
For patients with D-IBS, the relationship between mast cell counts in terminal ileum and maximally tolerable pressure was positive, however, it was not significant (r = 0.36, P> 0.05) (Fig. 3). Therefore, to verify the correlation between mast cell counts and rectal hypersensitivity, patients with IBS were divided into rectal hypersensitivity (+) and (–) groups by the distension level of 34 mmHg, which was the most efficient threshold of maximally tolerable pressure to identify IBS. Mast cell counts were significantly higher in the rectal hypersensitivity (–) group than in the rectal hypersensitivity (+) group for the terminal ileum, ascending colon and rectum (P < 0.05) (Fig. 4).
Correlation between mucosal mast cell counts in the terminal ileum and the maximally tolerable pressure in patients with irritable bowel syndrome (IBS). In patients with IBS (), the relationship between the two variables was positive with the same result for the ascending colon and rectum, however, this was not significant (P > 0.05, respectively).
Correlation between mucosal mast cell counts and rectal hypersensitivity. (a) Patients with irritable bowel syndrome (IBS) were divided into the rectal hypersensitivity (+) and (-) groups by the distension level of 34 mmHg, which was the most efficient threshold of maximally tolerable pressure to identify IBS. (b) Mast cell counts were significantly higher in the rectal hypersensitivity (-) group than in the rectal hypersensitivity (+) group for the terminal ileum, ascending colon and rectum (P < 0.05, respectively). AC, ascending colon; TI, terminal ileum; RT, rectum; Hyper (-), Rectal hypersensitivity (-) group; Hyper (+), Rectal hypersensitivity (+) group.
J Gastroenterol Hepatol. 2006;21(1):71-78. © 2006 Blackwell Publishing
Cite this: Mucosal Mast Cell Counts Correlate With Visceral Hypersensitivity in Patients With Diarrhea Predominant Irritable Bowel Syndrome - Medscape - Jan 01, 2006.