Periodontal disease has been associated with heart problems. Now investigators find that such gum infections may also be tied to the autoimmune condition rheumatoid arthritis.
What Is the Connection?
The study identified a type of bacteria, Aggregatibacter actinomycetemcomitans, that provokes the immune system into overreacting in both gum disease and severe arthritis. Doctors have long suspected a link between RA and periodontal infections, but they had not identified the responsible germ.
Protein Citrullination:
A. actinomycetemcomitans apparently puts a process called protein citrullination into overdrive. Hypercitrullination in turn signals the immune system to produce antibodies against these proteins.
Autoimmune Destruction:
The antibodies also attack the individual’s tissues and cause destruction. That is a hallmark of rheumatoid arthritis.
Not everyone with rheumatoid arthritis is infected with the bacteria that has been identified, so the researchers will now be looking for others that act in a similar manner to trigger an overactive autoimmune response. It might eventually lead to the development of medications that could kill the germs triggering the inflammation and thus stop joint destruction before it gets too far along.
Science Translational Medicine, Dec. 14, 2016
Other risk factors have been identified for rheumatoid arthritis. Some research shows that people who have been exposed to mercury are more likely to develop RA. Sun exposure (and presumably the attendant vitamin D produced by sunlit skin) appears to be protective.
Rheumatoid arthritis has also been associated with inflammation of the blood vessels (Best Practice & Research. Clinical Rheumatology, Oct., 2016). We don’t know if the inflammation is caused by infection with A. actinomycetemcomitans, but infection may cause inflammation, and inflammation of blood vessels might contribute to heart trouble. Other infections, such as Bartonella, have also been linked to RA.
