Increased intestinal luminal carbon monoxide gas in patients with ulcerative colitis

Abstract

Summary Background Recent studies in models of inflammatory bowel disease have demonstrated that heme oxygenase‐1 (HO‐1) induction, or its by‐products in this process such as carbon monoxide (CO), plays an important role in the intestinal inflammation. However, the distribution of HO‐1 in intestinal mucosa and the concentration of intestinal luminal CO in humans have not yet been investigated. Aim To detect the HO‐immunopositive cells in the intestine of normal subjects and in patients with ulcerative colitis (UC) and to measure intestinal luminal CO gas contents using gas chromatography. Materials and Methods The expression of HO‐1 in the intestine was determined using immunohistochemistry. Human colonic gas was collected using colonoscopy from healthy volunteers and patients with UC. Analysis of intestinal luminal gas was performed using a newly developed portable gas chromatograph. Results Immunopositive staining for HO‐1 was localized in the inflammatory cells, mainly mononuclear cells, and the number of cells that accepted stain was greater in patients with UC. CO level in the intestinal lumen significantly increased in patients in the active stage of UC. Conclusion These findings indicate that the HO‐CO system is induced in UC.