title: Decreased histamine catabolism in the colonic mucosa of patients with colonic adenoma.
abstract: 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.
authors.affiliation: Radiologisches Institut, Universität Erlangen-Nürnberg, Maximiliansplatz 1, 91054 Erlangen, Germany. michael.kuefner@idr.imed.uni-erlangen.de
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kuefner
authors.forename: Hubert G
authors.initials: HG
authors.lastname: Schwelberger
authors.forename: Eckhart G
authors.initials: EG
authors.lastname: Hahn
authors.forename: Martin
authors.initials: M
authors.lastname: Raithel
mesh_terms: 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
chemical_list: D006632:Histamine; D006631:Amine Oxidase (Copper-Containing); D006637:Histamine N-Methyltransferase