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Press release.
20/10/2008
A key bacterium in Crohn’s Disease
INRA - Inserm - AP-HP
French researchers from INRA and Inserm, in collaboration with AP-HP, have identified a species of bacteria that is key to Crohn’s disease. The fact that it is present in very small amounts, or even absent, in people with Crohn’s disease appears to explain the deregulation of their intestinal immune defence system. In addition to being involved in Crohn’s disease, this bacterium has beneficial properties that could be used to develop a new probiotic. This research is published in the 20 October 2008 online Early Edition of PNAS.
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Crohn’s disease is a chronic inflammatory bowel disease in which the immune system is improperly activated by intestinal bacteria (called “intestinal microbiota”). It appears in the form of attacks followed by periods of remission, and is characterised by abdominal pain, weight loss, diarrhoea and fever. It has a significant impact on patients’ quality of life, and the chronic nature of the disease makes it quite disabling. In a number of cases, complications related to Crohn’s disease require intestinal surgery.
In the first phase of this study, Philippe Langella, Joël Doré, Philippe Seksik, Harry Sokol and their colleagues showed that the microbiota of patients with Crohn’s disease had a marked deficiency of bacteria in the Clostridium leptum group. Upon further analysis, the authors discovered that the presence, in very small amounts, of a major member of this group, the bacteria Faecalibacterium prausnitzii, was responsible for a large portion of this deficiency.
Additionally, in patients who had required surgery, the risk of early recurrence was greater the lower the level of F. prausnitzii in the bowel. Researchers are harnessing these patient results to better understand and characterise this bacteria.
In the second part of the study, the authors demonstrated in vitro that F. prausnitzii has significant anti-inflammatory properties. This activity is associated with molecules directly secreted by the bacterium. These initial observations on cultured cells were confirmed in an animal model that mimics the effects of human Crohn’s disease. Administration of F. prausnitzii or the molecules that it secretes reduced intestinal inflammation and distinctly improved survival in mice.
Administration either orally or by injection suggests that F. prausnitzii is diffused through blood circulation. “This latest approach is significant for the development of future treatments,” the researchers note, “but the nature of the molecules secreted by this bacterium remains to be discovered.”
Nonetheless, this is the first time a bacterium with such properties that is naturally present in the body has been identified from analysing patients with Crohn’s disease. Continued work on this research by Inserm and INRA in collaboration with APHP could lead to the production of a new probiotic or to the development of new treatments for chronic intestinal inflammatory diseases.
Intestinal mucosa of a patient with Crohn’s disease and accompanying bacteria.
© Nadia Vasquez, CNAM
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Inflammatory Bowel Diseases
Crohn’s disease and ulcerative colitis are chronic inflammatory bowel diseases (IBD). The prevalence of these diseases in Western countries is 1/1000. Crohn’s disease can affect the entire digestive tract, while ulcerative colitis affects only the colon and rectum. Treatments for Crohn’s disease are burdensome, only address the symptoms, and can cause side effects. Surgery, which consists of removing the overly inflamed portion of the bowel, is necessary for half of patients.
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> Reference:
Sokol H, B Pigneur, L Watterlot, O Lakhdari, LG Bermúdez-Humarán, JJ Gratadoux, S Blugeon, C Bridonneau, JP Furet, G Corthier, C Grangette, N Vasquez, P Pochart, G Trugnan, G Thomas, H M. Blottière, J Doré, P Marteau, P Seksik, et P Langella.
« Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified by gut microbiota analysis of Crohn's disease patients”. PNAS online early edition 20 October 2008.
www.pnas.org/cgi/doi/10.1073/pnas.0804812105
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Written by :
INRA press service, phone: +33 (0)1 42 75 91 69
Sylvie Colleu, 33 (0)1 42 75 95 55 or Evelyne Lhoste, 33 (0)1 34 65 20 03 or Inserm Press Service, tel: 33 (0)1 44 23 60 98 or AP-HP Press service, tel: 33 (0)1 40 27 37 22
Contacts :
Scientific contacts:
> Philippe Langella, Ecology and Physiology of the Digestive Tract Research Unit, INRA Jouy-en-Josas
Tel: 33 (0)1 34 65 20 70 or 33 (0)6 89 64 33 21
philippe.langella@jouy.inra.fr, site: http://www.jouy.inra.fr/uepsd
> Joël Doré, Ecology and Physiology of the Digestive Tract Research Unit, INRA Jouy-en-Josas
Tel: 33 (0)1 34 65 27 09 or 33 (0)6 14 03 44 48 joel.dore@jouy.inra.fr
> Philippe Seksik, INSERM U538, Université Pierre & Marie Curie, AP-HP (Hôpital Saint-Antoine), Paris, tel: 33 (0)1 49 28 31 64
philippe.seksik@sat.ap-hop-paris.fr
> Harry Sokol, INSERM U538, Université Pierre & Marie Curie, AP-HP (Hôpital Saint-Antoine), Paris
harry.sokol@sat.aphp.fr
> Philippe Marteau, AP-HP (Hôpital Lariboisière), Paris, tel: 33 (0)1 49 95 25 78, philippe.marteau@lrb.aphp.fr
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