Collaborative effects of multiple bacterial strains in the gut may help prevent onset of certain inflammatory diseases

September 27, 2013
Figure 1: Inflammatory damage to the intestinal epithelium in a mouse model of colitis (left) is greatly reduced after oral administration of a mixture of 17 Clostridia strains (right). Credit: 2013 K. Atarashi et al.

At first, it may sound alarming to learn that a population of bacteria in your gut is conspiring to suppress your immune system—however, this is actually good news. By identifying the strains responsible, a research team led by Kenya Honda of the RIKEN Center for Integrative Medical Sciences may have uncovered a promising avenue of treatment for certain inflammatory disorders.

Immune cells known as regulatory T (Treg) cells are in part responsible for preventing the immune system from overreacting to foreign molecules or attacking healthy tissue. It is well established that immune function is affected by the diverse microbial community within the digestive tract, and Honda's team previously discovered that bacteria belonging to the genus Clostridium act on this particular immune pathway in mice to exert a strong anti-inflammatory effect.

"We showed that they were responsible for triggering production of Treg cells in the colon of mice," says Honda, "and that oral administration of these strains protected mice against colitis and systemic allergic responses."

Honda and his colleagues have now verified the existence of an equivalent in humans. They obtained a from a healthy volunteer and subjected it to the same purification regimen that yielded the Clostridia subpopulation identified in mice. When these bacteria were transplanted into the colons of 'germ-free' mice, in which the normal population of is entirely absent, they exerted a potent immunomodulatory effect. Through of this microbial cohort, the researchers zoomed in on a specific subset of 17 distinct Clostridia strains.

These strains collectively secrete a host of signaling molecules that promote Treg cell activation. "None of the organisms alone were nearly as potent as when they were in consortium," says Honda. "This suggests that cooperation between the strains is essential to their therapeutic effects." The collective benefit also appears to pertain to humans; analysis of the gut 'microbiome' in healthy patients versus individuals with ulcerative colitis revealed that all 17 strains were present at significantly lower levels in the latter group.

Accordingly, oral administration of this 17-microbe 'cocktail' greatly mitigated intestinal inflammation in mouse models of allergic diarrhea and ulcerative colitis (Fig. 1), suggesting the potential for a more 'natural' treatment of such conditions in humans. "A substantial number of patients don't benefit from existing drugs, which also have considerable adverse effects," says Honda. "We want to clinically test our hypothesis that reconstituting these bacteria to normal levels in patients may help restore immune tolerance and resolve chronic inflammatory processes."

Explore further: Mucus might prove useful in treating IBD, ulcerative colitis and Crohn's disease

More information: Atarashi, K., et al. Treg induction by a rationally selected mixture of Clostridia strains from the human microbiota. Nature 500, 232–236 (2013). dx.doi.org/10.1038/nature12331

Related Stories

Mucus might prove useful in treating IBD, ulcerative colitis and Crohn's disease

September 26, 2013
Imagine mucus—which most people find unpleasant—actually helping your body maintain its equilibrium, prevent inflammation, and reduce food allergy problems.

Breast is best: Good bacteria arrive from mum's gut via breast milk

August 21, 2013
Scientists have discovered that important 'good' bacteria arrive in babies' digestive systems from their mother's gut via breast milk.

Genetically engineered bacteria could help in Crohn's and colitis

November 2, 2012
(Medical Xpress)—A new study in mice has shown that genetically engineered bacteria can protect against inflammatory bowel disease (IBD), which includes a host of conditions including ulcerative colitis and Crohn's disease.

Females fend off gut diseases

June 11, 2013
At least among mice, females have innate protection from certain digestive conditions, according to a new Michigan State University study.

Team explores the effects of exercise on ulcerative colitis

July 2, 2013
Aerobic exercise can lessen – or worsen – the symptoms of inflammatory bowel diseases such as ulcerative colitis, depending on the circumstances under which the exercise is undertaken, researchers report.

Recommended for you

Breathing exercises help asthma patients with quality of life

December 13, 2017
A study led by the University of Southampton has found that people who continue to get problems from their asthma, despite receiving standard treatment, experience an improved quality of life when they are taught breathing ...

Study highlights the need for research into prevention of inflammatory bowel disease

December 7, 2017
Countries in Africa, Asia, the Middle East and South America have seen a rise in incidence of inflammatory bowel disease as they have become increasingly industrialised and westernised, a new study has found.

Air pollution can increase asthma risk in adults, even at low levels

November 24, 2017
Living close to a busy road can be bad for your respiratory health if you are middle aged, new Australian research has found.

Evidence found of oral bacteria contributing to bowel disorders

October 20, 2017
(Medical Xpress)—An international team of researchers has found evidence that suggests certain types of oral bacteria may cause or exacerbate bowel disorders. In their paper published in the journal Science, the group describes ...

New compound discovered in fight against inflammatory disease

September 22, 2017
A 10-year study by University of Manchester scientists for a new chemical compound that is able to block a key component in inflammatory illness has ended in success.

Asthma researchers test substance from coralberry leaves

September 14, 2017
The coralberry could offer new hope for asthmatics. Researchers at the University of Bonn have extracted an active pharmaceutical ingredient from its leaves to combat asthma, a widespread respiratory disease. In mice, it ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.