New study describes how poor oral health may worsen gut inflammation

Inflammatory bowel disease (IBD), which included Crohn's disease and ulcerative colitis, and afflicts an estimated 3 million adults in the United States, may be the latest condition made worse by poor oral health, according to a new study published in the journal Cell.

The study shows two pathways by which oral bacteria appear to worsen gut inflammation. In the first pathway, periodontitis, the scientific name for gum disease, leads to an imbalance in the normal healthy microbiome found in the mouth, with an increase of bacteria that cause inflammation. These disease-causing bacteria then travel to the gut.

However, this alone may not be enough to set off gut inflammation. The researchers demonstrated that oral bacteria may aggravate gut inflammation by looking at microbiome changes in mice with inflamed colons.

In the second proposed pathway, periodontitis activates the immune system's T cells in the mouth. These mouth T cells travel to the gut where they, too, exacerbate inflammation. The gut's normal microbiome is held in balance by the action of inflammatory and regulatory T cells that are fine-tuned to tolerate the resident bacteria. Oral inflammation generates mostly inflammatory T cells that migrate to the gut, where they, removed from their normal environment, end up triggering the gut's immune response, worsening disease, the researchers said.

The study has implications for novel treatments for IBD, the researchers said.