Therapeutic options in inflammatory bowel disease: experimental evidence of a beneficial effect of kinin B1 receptor blockade.

A surprising proportion of patients with inflammatory bowel disease (IBD) remain refractory to all classes of drugs presently in clinical use. Kinins are inflammatory mediators of potential relevance in IBD, because at least the kinin B1 receptor subtype is upregulated in human or animal intestinal inflammation and also both B1 and B2 receptors for kinins support inflammation and epithelial electrogenic ion transport that leads to secretory diarrhoea. In this issue of the BJP, Hara et al. report the therapeutic effect of a modern and selective nonpeptide kinin B1 receptor antagonist, SSR240612 ((2R)-2-(((3R)-3-(1,3-benzodioxol-5-yl)-3-(((6-methoxy-2-naphthyl)sulphonyl)amino)propanoyl)amino)-3-(4-((2R,6S)-2,6-dimethylpiperidinyl)methyl)phenyl)-N-isopropyl-N-methylpropanamide hydrochloride), with benefits such as decreased neutrophil influx and improved macroscopic tissue scoring. The results were corroborated using kinin B1 receptor gene-knockout mice. Further, kinin B1 receptor upregulation in this inflammatory model is partially dependent on TNF-alpha, a recognized target for IBD pharmacotherapy. More work is warranted to evaluate the value of the kinin B1 receptor antagonists as a novel anti-inflammatory therapeutic option for IBD.