New study from Tokyo Medical and Dental University focused on how bacteria from periodontal (gum) disease may worsen rheumatoid arthritis (RA), an inflammatory joint disease. Periodontal disease, a common condition affecting the gums, often arises from bacteria that build up on teeth. One particular bacterium, Aggregatibacter actinomycetemcomitans, has been found to not only impact gum health but also increase inflammation in the body.
The research team from Tokyo Medical and Dental University wanted to understand how this bacterium might affect arthritis. They conducted experiments using mice with RA-like symptoms and found that when these mice were infected with A. actinomycetemcomitans, their arthritis symptoms got worse. Specifically, their joints became more swollen, inflamed, and filled with immune cells, likely due to a chemical called IL-1β, which promotes inflammation.
They discovered that this worsening effect involved immune cells called macrophages. When researchers reduced the number of macrophages, arthritis symptoms improved, indicating these cells play a role in worsening RA.
Further analysis revealed that this bacterial infection activates a molecular complex in the body called the inflammasome, which amplifies inflammation. Importantly, mice lacking a specific protein, caspase-11, showed reduced inflammasome activation and, therefore, less severe arthritis symptoms. This suggests that both caspase-11 and the inflammasome are critical in linking periodontal bacteria to RA.
In summary, the study provides new insights into how periodontal disease might contribute to RA by activating inflammatory pathways. These findings may help researchers develop new RA treatments targeting inflammation caused by periodontal bacteria, potentially benefiting patients with other inflammation-related conditions like Alzheimer’s disease.
Source: ScienceDaily