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Induction of colonic transmural inflammation by Bacteroides fragilis: implication of matrix metalloproteinases

Carlos Medina1, Alfredo Santana, Marta Llopis

  • 1Gastroenterology Department and Research Unit, Hospital Universitario de Canarias, La Laguna, Tenerife, Spain. cmedinammar@hotmail.com

Inflammatory Bowel Diseases
|January 29, 2005
PubMed
Abstract

Insights

Bacteroides fragilis metalloproteinases (MMPs) contribute to transmural inflammation in the gut. Inhibiting bacterial MMPs reduced inflammation, suggesting their role in intestinal disease pathogenesis.

Area of Science:

  • Microbiology
  • Gastroenterology
  • Immunology

Background:

  • Commensal bacteria play a role in intestinal inflammation.
  • The exact mechanisms of bacterial involvement in gut inflammation remain unclear.
  • Bacteroides fragilis-produced metalloproteinases (MMPs) are hypothesized to facilitate bacterial migration and transmural inflammation.

Purpose of the Study:

  • To investigate the role of bacterial MMP activity in an experimental model of colitis.
  • To determine if MMP inhibition affects bacterial translocation and inflammation.

Main Methods:

  • Intramural injection of viable B. fragilis or Escherichia coli into the colonic wall of rats.
  • Administration of the MMP inhibitor phenanthroline to assess its effect on lesion scores.
  • Measurement of MMP activity in bacterial suspensions using an azocoll assay.

Main Results:

  • B. fragilis inoculation induced chronic, subserosal inflammatory lesions, while E. coli caused acute, widespread inflammation.
  • Phenanthroline treatment significantly reduced subserosal lesion scores in B. fragilis-inoculated rats.
  • B. fragilis suspensions exhibited MMP activity, unlike E. coli. Sonication reduced B. fragilis MMP activity and virulence.

Conclusions:

  • Bacterial MMPs are implicated in the serosal migration of B. fragilis.
  • Bacterial MMPs may contribute to the induction of transmural inflammation in the colon.
  • Targeting bacterial MMPs could be a therapeutic strategy for intestinal inflammation.

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