Subclinical mucosal inflammation in diarrhea-predominant irritable bowel syndrome (IBS) in a tropical setting

• Published in: Scandinavian journal of gastroenterology Vol. 47; no. 6; p. 619
• Main Authors: De Silva, Arjuna Priyadarsin, Nandasiri, Shanika Dulanjalee, Hewavisenthi, Janaki, Manamperi, Aresha, Ariyasinghe, Madurangi Prasadi, Dassanayake, Anuradha Supun, Jewell, Derek P, de Silva, Hithanadura Janaka
• Format: Journal Article
• Language: English
• Published: England 01.06.2012
• Subjects: Adolescent; Adult; Biomarkers - metabolism; Biopsy; Case-Control Studies; Colon - metabolism; Colon - pathology; Colonoscopy; Diarrhea; Eosinophils - metabolism; Female; Gastroenteritis - complications; Humans; Ileum - metabolism; Ileum - pathology; Interleukin-10 - metabolism; Interleukin-8 - metabolism; Intestinal Mucosa - metabolism; Intestinal Mucosa - pathology; Irritable Bowel Syndrome - etiology; Irritable Bowel Syndrome - metabolism; Irritable Bowel Syndrome - pathology; Male; Middle Aged; Prospective Studies; Reverse Transcriptase Polymerase Chain Reaction; Sri Lanka; Tropical Climate; Young Adult; Sri Lanka
• ISSN: 1502-7708
• DOI: 10.3109/00365521.2012.666672

There is evidence for low-grade inflammation in the pathophysiology of post-infectious irritable bowel syndrome (IBS). We assessed the degree of subclinical intestinal mucosal inflammation in diarrhea-predominant IBS (IBS-D) in a tropical setting. In a prospective study over 1 year, we investigated 49 patients with IBS-D (cases; median age 34 years (range 18-59); M:F 36:13), diagnosed on Rome III criteria. 14 individuals with a family history of colon cancer (median age 46.5 years (range 23-56); M:F 6:8) were selected as controls. Stools of cases and controls were tested for calprotectin. During colonoileoscopy, serial biopsies were obtained. Mucosal mast cells, neutrophils, eosinophils and lymphocytes/plasma cell infiltrate were quantified. Tissue expression of IL-8 and IL-10 was assessed in biopsies by semi-quantitative RT-PCR. A history suggestive of an episode of infectious diarrhea (ID) was present in 16/49 cases and 0/14 controls (p = 0.013). In cases, there were significantly more mucosal mast cells in the ileum and all segments of colon and significantly more eosinophils in the cecum. Tissue expression of IL-8 was significantly higher and IL-10 significantly lower in cases compared with controls (target/standard cDNA ratio, median (range) IL-8: 1.25 (0.75-2) vs. 0.85 (0.63-1.3), p < 0.0001, Mann-Whitney U test; IL-10: 0.33 (0-0.63) vs. 0.55 (0.5-0.7), p < 0.0001). There was a significant inverse correlation between IL-8 and IL-10 expression (Pearson correlation, (-) 0.509; p < 0.01). There was evidence of subclinical intestinal mucosal inflammation in patients with IBS-D. The finding of increased eosinophils is novel, and may be of special relevance to IBS-D in the tropics.