Decreased histamine catabolism in the colonic mucosa of patients with colonic adenoma.
BACKGROUND
Alterations in mucosal histamine degradation play an important role in various gastrotinestinal diseases including colonic adenoma. In humans, histamine can be catabolized either by oxidative deamination by diamine oxidase (DAO) or by ring methylation by histamine N-methyltransferase (HNMT). The significance of HNMT in this context was investigated for the first time in this project.


METHODS
About 94 colonic biopsies were endoscopically obtained from 23 patients suffering from colonic adenoma and 26 biopsies from six healthy individuals. Each sample was mechanically homogenized, homogenates were cleared by centrifugation and used for determination of protein and histamine concentrations and enzyme activities of DAO and HNMT by radiometric assay.


RESULTS
In adenoma patients DAO activities were slightly and HNMT activities were significantly decreased in normal mucosa compared to controls. Activities of both enzymes were significantly lower in adenoma tissue than in healthy mucosa in the same patients. A significant correlation was found between HNMT and DAO in all investigated samples. Histamine concentrations were elevated in adenoma patients.


CONCLUSIONS
Histamine catabolism is decreased in the colonic mucosa of patients with colonic adenoma.
Kuefner
Michael A
MA
Radiologisches Institut, Universität Erlangen-Nürnberg, Maximiliansplatz 1, 91054 Erlangen, Germany. michael.kuefner@idr.imed.uni-erlangen.de
Schwelberger
Hubert G
HG
Hahn
Eckhart G
EG
Raithel
Martin
M
D000236:Adenoma / Q000378:metabolism*; D018253:Adenoma, Villous / Q000378:metabolism; D000328:Adult; D000368:Aged; D006631:Amine Oxidase (Copper-Containing) / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism*; D005260:Female; D006632:Histamine / Q000378:metabolism*; D006637:Histamine N-Methyltransferase / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
D006632:Histamine; D006631:Amine Oxidase (Copper-Containing); D006637:Histamine N-Methyltransferase