Histamine exhibits various biological effects in inflammatory and immunological reactions. To further define its potential role in allergic enteropathy and inflammatory bowel disease, both gut mucosal histamine levels and histamine release from endoscopic biopsy samples were measured. Tissue histamine content resulted from addition of the released amount of histamine and the remaining part of tissue histamine. The results demonstrate highly elevated mucosal histamine levels of the large intestine in allergic enteropathy. In inflammatory bowel disease histamine content and secretion were found to be significantly increased particularly in affected mucosa of Crohn’s disease and ulcerative colitis than in unaffected tissue or in healthy controls. These findings give strong evidence that mast cell mediators like histamine play a role in the pathogenesis of these diseases. Mucosal histamine is thus concluded to contribute to the immunoinflammatory reactions of the intestine found in these disease states and to reflect the degree of colonic inflammation in Crohn’s disease and ulcerative colitis.

This kinetic study was performed to investigate the different tissue-influencing histamine amounts in Crohn's Disease (CD), Ulcerative Colitis (UC), patients with polyps and cancers (P.a.C.Gr) and in a Control Group (CG). For this purpose the endoscopically obtained specimens from rectal mucosa were immediately placed into 1000 microliters of Hank's incubation medium in order to determine the spontaneously released histamine amounts at the time points of 5, 10, 15, 20 and 30 minutes. Each time a volume of 100 microliters was removed from the incubation medium and the kinetic value (KV) was detected by using the single isotope radioenzymatic method. Influencing of natural histamine catabolism and the comparison of the tissue histamine release with or without air oxygen in the incubation medium using four kinetic programmes (KP1-4) provides clearly different KVs, not only between the KPs but also within the same KP. The P.a.C.Gr. shows higher kinetic values (KVs) compared with the CG. In KP1-3 the kinetic courses (KCs) of the Inflammatory Bowel Diseases (IBDs), CD and UC-both not yet divided in active (a.) or not active (n.a.) disease stages-cross the KCs of the CG several times. Only the differentiation of the IBDs in active and not active disease stages in KP4 reveals that CDa. and UCa. stand out from the CG by higher KVs, and in contrast, CDn.a. and UCn.a. have lower KVs than the CG. The released amounts of histamine in CDa. and UCa. are significantly higher than in CDn.a. and UCn.a.