title: Human rectal mucosal gene expression after consumption of digestible and non-digestible carbohydrates.
abstract: The effect of regular consumption of the low-digestible and prebiotic isomalt versus the digestible sucrose on gene expression in rectal mucosa was examined in a randomized double-blind crossover trial. Nineteen healthy volunteers received 30 g isomalt per day or 30 g sucrose as part of a controlled diet over two 4-week test periods with a 4-week washout period in between. At the end of each test phase rectal biopsies were obtained. After RNA extraction mucosal gene expression was assayed using GeneChip microarrays. In addition, expression of cathelicidin hCap18/LL37, cellular detoxification enzymes GSTpi, UGT1A1 and CYP3A4, cyclooxygenase 2 and barrier factors MUC2 and ZO-1 were determined by real-time RT-PCR. Microbiological analyses of fecal samples revealed a shift of the gut flora towards an increase of bifidobacteria following consumption of the diet containing isomalt. Isomalt consumption did not affect rectal mucosal gene expression in microarray analyses as compared to sucrose. In addition, the expression of cathelicidin LL37, GSTpi, UGT1A1, CYP3A4, COX-2, MUC2 and ZO-1 was not changed in rectal biopsies. We conclude that gene expression of the human rectal mucosa can reliably be measured in biopsy material taken at endoscopy. Dietary intervention with the low digestible isomalt compared with the digestible sucrose did not affect gene expression in the lining rectal mucosa.
authors.affiliation: Department of Medicine II, Division of Gastroenterology, University of Würzburg, Würzburg, Germany. jschauber@ucsd.edu
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schauber
authors.forename: Frank
authors.initials: F
authors.lastname: Weiler
authors.forename: Andrea
authors.initials: A
authors.lastname: Gostner
authors.forename: Ralph
authors.initials: R
authors.lastname: Melcher
authors.forename: Theodor
authors.initials: T
authors.lastname: Kudlich
authors.forename: Hardi
authors.initials: H
authors.lastname: Lührs
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Scheppach
mesh_terms: D000328:Adult; D001706:Biopsy; D051546:Cyclooxygenase 2 / Q000235:genetics; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000378:metabolism; D004063:Digestion; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D014453:Glucuronosyltransferase / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D053538:Keratin-18 / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000032:analysis; D012007:Rectum / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000099148:UGT1A1 Enzyme
chemical_list: D051546:Cyclooxygenase 2; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System; D004040:Dietary Carbohydrates; D014453:Glucuronosyltransferase; D005982:Glutathione Transferase; D053538:Keratin-18; D012333:RNA, Messenger; D000099148:UGT1A1 Enzyme; C510163:CYP3A4 protein, human