Health & Medicine

Gut Bacteria Boosts the Immune System: Combating Inflammatory Bowel Disease

Catherine Griffin
First Posted: Nov 14, 2013 10:10 AM EST

Gut bacteria has proven to be crucial to the human body. It can promote gastrointestinal health and can even impact mood. Now, scientists have taken a closer look at the role of gut bacteria when it comes to the maturation of the immune system; it turns out that they've uncovered evidence supporting the use of butyrate, an acid produced by gut bacteria, as therapy for inflammatory bowel diseases.

Previous studies have shown that patients suffering from inflammatory bowel disease lack butyrate-producing bacteria and have lower levels of butyrate in their gut. However, butyrate's anti-inflammatory properties were attributed to its role as a main energy source for the cells lining the colon. In order to examine the molecular basis for the role of butyrate, the researchers examined mice.

The scientists investigated the molecular mechanisms by which commensal microbes augment the number of regulatory T cells (Treg cells) present in the colon of mice that were bred germ-free. In the end, they found that butyric acid, a short-chain fatty acid produced by commensal bacteria, acts on naïve T cells to promote their differentiation into Treg cells. In order to do so, it uses epigenetic changes that regulate the expression of the genes responsible for differentiation of naïve T cells into Treg cells.

The findings reveal that the mice suffering from colitis actually improve when butyrate is added as part of their diet. Their levels of Treg cells increase and their symptoms improve.

"Regulatory T cells are important for the containment of excessive inflammatory responses as well as autoimmune disorders," said Hiroshi Ohno, one of the researchers, in a news release. "Therefore these findings could be applicable for the prevention and treatment of inflammatory bowel disease, allergy and autoimmune disease. Butyrate is natural and safe as a therapy and in addition to that it is cheap, which could reduce costs for both patients and society."

The findings are published in the journal Nature.

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