Background: Irritable bowel syndrome (IBS) reflects several pathogenetic entities including a subgroup with low-grade colonic inflammation. We propose that pathogenic bacteria act as triggers and that disturbances of commensal bacteria maintain low-grade inflammation, that in turn leads to dysfunction in the gut or brain. Methods: Studies were performed in mice under specific pathogen-free conditions. Visceral pain was assessed by the visceromotor response and motility was assessed by in vivo fluoroscopy and in vitro by muscle contractility. Brain chemistry was assessed by in situ hybridization and behavior by standard tests. The microbiota was monitored using 16s-based RT-PCR and DGGE. Results: Mice transiently infected with the nematode Trichinella spiralis exhibited changes in motility and in visceral perception that persisted for up to 6 weeks post-infection. This was accompanied by alterations in the microbiota and an upregulation of cyclooxygenase-2 which could be reversed by treatment with anti-inflammatory agents or selected probiotics. To investigate the contribution of the microbiota, we treated mice with oral antibiotics and monitored visceral perception and behavior. Antibiotic therapy produced substantial changes in the microbiota, a small increment in inflammatory activity and an increase in substance P or pain perception. Oral, but not systemic antibiotic treatment, produced changes in brain chemistry and an increase in anxiety-like behavior. Conclusion: These studies provide proof of concept that pathogenic microbes can induce persistent gut dysfunction and that changes in microbial composition of the gut can maintain gut dysfunction as well as induce behavioral changes reminiscent of the psychiatric comorbidity that occurs in up to 60% of irritable bowel syndrome patients.

Keywords:
Irritable bowel syndrome, Commensal bacteria, Trichinella spiralis
This content is only available via PDF.
© 2010 S. Karger AG, Basel
2010
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.