Novel insights which may translate into treatments for irritable bowel syndrome

Irritable bowel syndrome (IBS) is a very common functional disorder of the digestive tract. Despite the prevalence and the social impact of IBS, the exact etiopathogenesis is incomplete and the pharmacological treatment is unsatisfactory. In this research topic, Frontiers in Pharmacology brings together a group of review and original articles focusing on IBS. Fabrizio De Ponti brilliantly outlined the drugs currently used in—or in development for—IBS, within a scenario in which the specific armamentarium of medications is unsatisfactory (De Ponti, 2013). Jakub Fichna and Martin Storr focused their review article on the disturbances in the brain-gut axis as possible cause of IBS (Fichna and Storr, 2012). The Authors illustrated the pathophysiological mechanisms which contribute to the generation of IBS symptoms, with a special emphasis to stress, emotion and psychological factors. The future of anti-IBS drugs targeting the brain-gut axis were also highlighted. The bidirectional communication between the brain and the gut opens up new treatment possibility for IBS patients with mood disturbances that are refractory to first-and second-lines therapies. Jeremy Gale and Lesley Houghton reviewed the preclinical and clinical data which support the potential use of gabapentin and pregabalin in disorders characterized by visceral hypersensitivity, such as IBS (Gale and Houghton, 2011). Both gabapentin and pregabalin bind with high affinity to alpha 2 delta subunits of voltage-gated calcium channels and inhibit both visceral nociception and motility. Although limited, clinical studies on visceral pain are in agreement with animal results and support a continued research and development of the alpha 2 delta ligands in IBS. Eberlin et al. reviewed the pharmacokinetics, pharmacodynamics and clinical data of racecadotril, a powerful and selective enkephalinase inhibitor, which has emerged as a promising drug in the antisecretory therapy (Eberlin et al., 2012). In multiple direct comparative studies, racecadotril was at least as effective as loperamide in the treatment of acute diarrhoea, and exhibited significantly better tolerability. Although the results are robust and encouraging, the potential of racecadotril in D-IBS patients remains to be established.