Methylhistamine in Crohn's disease (CD): increased production and elevated urine excretion correlates with disease activity

The etiology of Crohn's disease (CD) is still unknown. Several lines of evidence point to mast cells as participants in the pathogenesis of CD. Mast cells can be found in all areas of the gastrointestinal tract and in all wall layers. They synthesize a variety of mediators (histamine, tryptase, TNF) that can induce both acute and chronic inflammation: features that can also be found in CD. In histological sections, an accumulation of degranulated mast cells in areas of active disease can be shown. One major inflammatory mediator of mast cells is histamine. Evidence for local up-regulation of mast cells at the mucosal level was found by determination of tissue histamine content and histamine release from vital CD-biopsies. To further clarify the role of histamine in CD, this study investigated n-tele-methylhistamine in untreated patients with CD.