Original article—alimentary tract
Alterations in Mucosal Immunity Identified in the Colon of Patients With Irritable Bowel Syndrome

https://doi.org/10.1016/j.cgh.2007.11.012Get rights and content

Background & Aims: Irritable bowel syndrome (IBS) has been associated with mucosal dysfunction, mild inflammation, and altered colonic bacteria. We used microarray expression profiling of sigmoid colon mucosa to assess whether there are stably expressed sets of genes that suggest there are objective molecular biomarkers associated with IBS. Methods: Gene expression profiling was performed using Human Genome U133 Plus 2.0 (Affymetrix) GeneChips with RNA from sigmoid colon mucosal biopsy specimens from 36 IBS patients and 25 healthy control subjects. Real-time quantitative polymerase chain reaction was used to confirm the data in 12 genes of interest. Statistical methods for microarray data were applied to search for differentially expressed genes, and to assess the stability of molecular signatures in IBS patients. Results: Mucosal gene expression profiles were consistent across different sites within the sigmoid colon and were stable on repeat biopsy over approximately 3 months. Differentially expressed genes suggest functional alterations of several components of the host mucosal immune response to microbial pathogens. The most strikingly increased expression involved a yet uncharacterized gene, DKFZP564O0823. Identified specific genes suggest the hypothesis that molecular signatures may enable distinction of a subset of IBS patients from healthy controls. By using 75% of the biopsy specimens as a validation set to develop a gene profile, the test set (25%) was predicted correctly with approximately 70% accuracy. Conclusions: Mucosal gene expression analysis shows there are relatively stable alterations in colonic mucosal immunity in IBS. These molecular alterations provide the basis to test the hypothesis that objective biomarkers may be identified in IBS and enhance understanding of the disease.

Section snippets

Participants and Collection of Colon Biopsy Samples

Our study included 36 IBS patients (21 IBS-D and 15 IBS-C) and 25 healthy controls. IBS participants were recruited by mail from an administrative database of 752 patients with IBS who reside within a 150-mile radius of Rochester, MN. All patients fulfilled the Rome II criteria for IBS diagnosis12 and had undergone clinical examination and investigation to exclude other gastrointestinal disorders. Predominant bowel dysfunction was confirmed at the time of the study by means of a validated bowel

Participants

Table 1 summarizes the information on participants in the study.

Histologic Assessment of Mucosal Biopsy Specimens

H&E-stained sigmoid biopsy specimens were normal in most healthy subjects and patients with IBS-C and IBS-D. One healthy subject and 2 patients with IBS-D had focal acute colitis. Melanosis coli was observed in 3 patients with IBS-C and in 1 patient with IBS-D. The thickness of the subepithelial collagen layer was at the upper limit of normal (ie, 10 μm) in 1 healthy subject, in 1 patient with IBS-C, and in 2 patients with IBS-D.

Discussion

This study shows the differential expression of several genes in the colonic mucosa of IBS patients. Many of these genes are directed toward the host defense mechanisms against microbiological pathogens; the well-established properties of the genes and their potential role in IBS are described in the supplementary Discussion section (see supplementary material online at www.cghjournal.org).25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38 A pictorial summary of these genes is provided in

References (44)

  • H. Kikuchi et al.

    NADPH oxidase subunit, gp91-phox homologue, preferentially expressed in human colon epithelial cells

    Gene

    (2000)
  • R.W. Harper et al.

    Differential regulation of dual NADPH oxidases/peroxidases, Duox1 and Duox2, by Th1 and Th2 cytokines in respiratory tract epithelium

    FEBS Lett

    (2005)
  • L. Ohman et al.

    A controlled study of colonic immune activity and beta7+ blood T lymphocytes in patients with irritable bowel syndrome

    Clin Gastroenterol Hepatol

    (2005)
  • T.R. Sana et al.

    Microarray analysis of primary endothelial cells challenged with different inflammatory and immune cytokines

    Cytokine

    (2005)
  • T. Ndolo et al.

    Expression of simian immunodeficiency virus Nef protein in CD4+ T cells leads to a molecular profile of viral persistence and immune evasion

    Virology

    (2006)
  • J.P. Ioannidis

    Microarrays and molecular research: noise discovery?

    Lancet

    (2005)
  • M. Camilleri

    Mechanisms in IBS: something old, something new, something borrowed

    Neurogastroenterol Motil

    (2005)
  • E. Malinen et al.

    Analysis of the fecal microbiota of irritable bowel syndrome patients and healthy controls with real-time PCR

    Am J Gastroenterol

    (2005)
  • H. Lettesjo et al.

    Detection of inflammatory markers in stools from patients with irritable bowel syndrome and collagenous colitis

    Scand J Gastroenterol

    (2006)
  • A.P. Weston et al.

    Terminal ileal mucosal mast cells in irritable bowel syndrome

    Dig Dis Sci

    (1993)
  • L.H. Wang et al.

    Bacillary dysentery as a causative factor of irritable bowel syndrome and its pathogenesis

    Gut

    (2004)
  • K.A. Gwee et al.

    Increased rectal mucosal expression of interleukin 1beta in recently acquired post-infectious irritable bowel syndrome

    Gut

    (2003)
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    Dr Camilleri is supported in part by grants DK 54681 and 02638 (studies in irritable bowel syndrome) and by RR024150 (Mayo Clinic CTSA) from the National Institutes of Health. This work was supported by a research grant from Johnson & Johnson Pharmaceutical Research & Development.

    A provisional patent application has been filed by the authors’ employers, Mayo Clinic and Janssen Pharmaceutica n.v., for the use of the discovered molecular signatures to diagnose IBS. The following authors were employees of Johnson & Johnson Pharmaceutical Research & Development, a division of Janssen Pharmaceutica n.v. at the time when the study was performed and the manuscript drafted: Jeroen Aerssens, Willem Talloen, Leen Thielemans, Hinrich W. H. Göhlmann, Ilse Van den Wyngaert, Theo Thielemans, and Bernard Coulie.

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