The Histamine H4 Receptor: A Novel Target for Safe Anti-inflammatory Drugs?

Abstract

The functional role of histamine H4 receptors (H4Rs) in the Gastrointestinal (GI) tract
is reviewed, with particular reference to their involvement in the regulation of gastric mucosal
defense and inflammation. H4Rs have been detected in different cell types of the gut, including
immune cells, paracrine cells, endocrine cells and neurons, from different animal species and
humans; moreover, H4R expression was reported to be altered in some pathological conditions,
such as colitis and cancer. Functional studies have demonstrated protective effects of H4R antagonists
in several experimental models of gastric mucosal damage and intestinal inflammation,
suggesting a potential therapeutic role of drugs targeting this new receptor subtype in GI
disorders, such as allergic enteropathy, Inflammatory Bowel Disease (IBD), Irritable Bowel
Syndrome (IBS) and cancer.