title: Butyrate enemas do not affect human colonic MUC2 and TFF3 expression.
abstract: BACKGROUND
  The colonic mucus layer plays an important role in the protection of the intestinal epithelium and mainly consists of mucin glycoproteins (primarily MUC2 in the colon) trefoil factor 3 (TFF3) and secretory IgA. Butyrate is a major end product of fermentation of dietary fibres and is associated with beneficial effects on colonic health. Earlier in-vitro and animal studies showed that butyrate modulates MUC2 and TFF3 expression and mucin secretion, although data from human studies are not yet available.
  
  
  METHODS
  Sixteen healthy volunteers and 35 ulcerative colitis (UC) patients in clinical remission self-administered a 60 ml rectal enema containing 100 mmol/l butyrate or placebo once daily for 2 and 3 weeks, respectively. After each treatment, biopsies were taken from the distal sigmoid for quantitative RT-PCR and immunohistochemical analysis of MUC2 and TFF3. In addition, mucosal sections were stained with high iron diamine-alcian blue to distinguish between sialomucins and sulphomucins. To analyse total mucin secretion and secretory IgA concentrations, 24 h faeces were collected during the day before the endoscopic examination.
  
  
  RESULTS
  The butyrate intervention did not significantly modulate the expression of MUC2 (fold change: 1.04 and 1.05 in healthy volunteers and ulcerative colitis patients, respectively) or TFF3 (fold change: 0.91 and 0.94 in healthy volunteers and UC patients, respectively). Furthermore, the percentage of sialomucins, mucus secretion and secretory IgA concentrations were not affected by the butyrate intervention in both the groups.
  
  
  CONCLUSIONS
  Butyrate exposure in healthy volunteers and UC patients in remission did not affect the measured parameters of the colonic mucus layer.
authors.affiliation: TI Food and Nutrition, Wageningen, The Netherlands.
authors.forename: Henrike M
authors.initials: HM
authors.lastname: Hamer
authors.forename: Daisy M A E
authors.initials: DM
authors.lastname: Jonkers
authors.forename: Ingrid B
authors.initials: IB
authors.lastname: Renes
authors.forename: Steven A L W
authors.initials: SA
authors.lastname: Vanhoutvin
authors.forename: Andrea
authors.initials: A
authors.lastname: Kodde
authors.forename: Freddy J
authors.initials: FJ
authors.lastname: Troost
authors.forename: Koen
authors.initials: K
authors.lastname: Venema
authors.forename: Robert-Jan M
authors.initials: RJ
authors.lastname: Brummer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002087:Butyrates / Q000008:administration & dosage*; D003093:Colitis, Ulcerative / Q000188:drug therapy* / Q000503:physiopathology; D003106:Colon / Q000187:drug effects* / Q000502:physiology; D004733:Enema / Q000379:methods*; D005243:Feces / Q000737:chemistry; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism; D007413:Intestinal Mucosa / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D055262:Mucin-2 / Q000235:genetics* / Q000378:metabolism; D010455:Peptides / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D052116:Sialomucins / Q000378:metabolism; D000071165:Trefoil Factor-3; D055815:Young Adult
chemical_list: D002087:Butyrates; D007070:Immunoglobulin A; C524625:MUC2 protein, human; D055262:Mucin-2; D010455:Peptides; D052116:Sialomucins; C082495:TFF3 protein, human; D000071165:Trefoil Factor-3