Reduced chromogranin A cell density in the ileum of patients with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder that considerably reduces the quality of life and productivity of patients. Chromogranin A (CgA) is a common marker for endocrine cells. CgA cell density has been reported to be reduced in the duodenum and colon of IBS patients. This study was undertaken to investigate CgA cell density in the ileum of these patients. The study involved 98 patients with IBS, according to the Rome III Criteria (77 females and 21 males, with an average age of 35 years). In total, 35 patients had diarrhoea-predominant symptoms (IBS-D), 32 had constipation-predominant symptoms (IBS-C), and 31 had a mixture of both diarrhoea and constipation (IBS-M). In this study, 27 subjects were used as controls (16 females and 11 males, with an average age of 52 years). Colonoscopies were performed on the patients and controls and biopsies were obtained from the ileum. Sections were immunostained with the avidin-biotin complex (ABC) for CgA and quantified using computerized image analysis. The CgA density in the controls was 63.2+/-4.4 (mean +/- SEM), for all IBS patients it was 28.6+/-2.1, for IBS-D it was 28.8+/-3.4, for IBS-M it was 26.5+/-3.9 and for IBS-C it was 30.3+/-3.7. There was a statistically significant difference between the controls and all IBS patients (IBS-D, IBS-M and IBS-C; P<0.0001 for all). The present study showed that CgA cell density in the ileum of IBS patients was reduced, regardless of subtype. Thus, it appears that there is endocrine cell depletion in both the small and large intestine of IBS patients, whereas IBS is normally considered to be a functional condition without any detectable abnormalities. The present finding lends support to the suggestion that IBS is caused by a biological abnormality, and intestinal CgA cell density may be used as a biological marker for the diagnosis of IBS.