title: DNA methylation of colon mucosa in ulcerative colitis patients: correlation with inflammatory status.
abstract: BACKGROUND
  Although DNA methylation of colonic mucosa in ulcerative colitis (UC) has been suggested, the majority of published reports indicate the correlation between methylation of colon mucosa and occurrence of UC-related dysplasia or cancer without considering the mucosal inflammatory status. The aim of this study was to verify whether mucosal inflammation-specific DNA methylation occurs in the colon of UC.
  
  
  METHODS
  Of 15 gene loci initially screened, six loci (ABCB1, CDH1, ESR1, GDNF, HPP1, and MYOD1) methylated in colon mucosa of UC were analyzed according to inflammatory status using samples from 28 surgically resected UC patients.
  
  
  RESULTS
  Four of six regions (CDH1, GDNF, HPP1, and MYOD1) were more highly methylated in the active inflamed mucosa than in the quiescent mucosa in each UC patient (P = 0.003, 0.0002, 0.02, and 0.048, respectively). In addition, when the methylation status of all samples taken from examined patients was stratified according to inflammatory status, methylation of CDH1 and GDNF loci was significantly higher in active inflamed mucosa than in quiescent mucosa (P = 0.045 and 0.002, respectively). Multiple linear regression analysis revealed that active inflammation was an independent factor of methylation for CDH1 and GDNF. DNA methyltransferase 1 and 3b were highly expressed in colon epithelial cells with active mucosal inflammation, suggesting their involvement in inflammation-dependent methylation.
  
  
  CONCLUSIONS
  Methylation in colonic mucosa of UC was correlated with mucosal inflammatory status, suggesting the involvement of methylation due to chronic active inflammation in UC carcinogenesis.
authors.affiliation: Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Saito
authors.forename: Jun
authors.initials: J
authors.lastname: Kato
authors.forename: Sakiko
authors.initials: S
authors.lastname: Hiraoka
authors.forename: Joichiro
authors.initials: J
authors.lastname: Horii
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Suzuki
authors.forename: Reiji
authors.initials: R
authors.lastname: Higashi
authors.forename: Eisuke
authors.initials: E
authors.lastname: Kaji
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kondo
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000032:analysis* / Q000378:metabolism*; D003093:Colitis, Ulcerative / Q000150:complications / Q000235:genetics* / Q000378:metabolism; D003106:Colon / Q000378:metabolism / Q000473:pathology*; D003110:Colonic Neoplasms / Q000209:etiology / Q000378:metabolism; D004247:DNA / Q000235:genetics; D019175:DNA Methylation; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007249:Inflammation / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011379:Prognosis; D055815:Young Adult
chemical_list: D015415:Biomarkers; D004247:DNA