Aminosalicylates and other anti-inflammatory compounds for irritable bowel syndrome

Growing evidence suggests that gastrointestinal immune activation may affect intestinal function and sensory perception, which contribute to symptom generation in patients with irritable bowel syndrome (IBS). The identification of higher counts of immunocytes (e.g. T cells and mast cells), mucosal and systemic immune activation, and increased mucosal permeability in patients with IBS has stimulated interest in the potential development of therapeutic approaches aimed at targeting the immune system and inflammation. Although an initial attempt in a pilot trial with steroids in patients with post-infective IBS failed, there has been renewed interest for mast cell stabilizers and the therapeutic potential of aminosalicylates. A recent randomized, double-blind, placebo-controlled pilot trial assessed the effect of mesalazine on intestinal immune cells and symptom perception in patients with IBS. Mesalazine markedly reduced mucosal immune cells and mast cells in particular, compared to placebo. In addition, mesalazine significantly improved general well-being. Mesalazine may enhance epithelial barrier function, and preliminary data suggest that it may alter faecal bacterial profiles in IBS patients. Nevertheless, the exact mechanism through which this drug affects immune activation in the intestine of patients with IBS remains unknown. There is a need for further studies to prove the efficacy of mesalazine for IBS. Further studies aimed at assessing the role of aminosalicylates and other approaches with potential anti-inflammatory activity, including probiotics, non-absorbable antibiotics, histamine receptor antagonists and protease inhibitors on IBS symptoms or pathophysiology are now warranted.