Inflammation associated with gum disease may help some patients fight infection

By Pamela DiSalvo Lepley and Suzanne Barbour

RICHMOND, Va. – A bioactive fat known as platelet-activating factor (PAF), which contributes to the inflammation associated with chronic gum disease, also may stimulate production of protective antibodies in some patients, suggests a new study by researchers at Virginia Commonwealth University.

The surprising results, reported in the Jan. 1 issue of the Journal of Immunology, could influence the way doctors treat periodontal disease, a chronic bacterial infection that affects the gums and bone supporting the teeth and that, left untreated, could result in tooth loss. The inflammation associated with periodontal disease also has been linked to heart disease, increased risk of stroke and delivery of pre-term, low-weight babies.

“You have to be judicious in how you treat periodontal disease,” says Suzanne E. Barbour, Ph.D., associate professor of microbiology and immunology at VCU. “In addition to fighting the bacterial infection with a regimen of antibiotics and sometimes surgery, a goal of current periodontal therapy is to reduce inflammation in the tissues surrounding the teeth. But these findings suggest that you may not want to shut down the inflammatory response entirely because of the antibodies being formed.

“The findings indicate that inflammation can be a protective response.” 

The VCU study, supported by a National Institute of Dental and Craniofacial Research grant, focused on aggressive periodontitis in teenagers and adults 35 and younger. The gum disease, which runs in families and is prevalent among African Americans, can lead to loss of many permanent teeth during the teens and early 20s. 

The study tested blood samples and found that young patients with gum disease secreted sharply lower levels of an enzyme known as Platelet-Activating Factor Acetylhydrolase (PAF-AH) than did healthy patients. PAF-AH breaks down PAF and, thereby, limits inflammation.  As a result, PAF should accumulate in the gums of those patients with periodontitis, prompting inflammation.

But, at the same time, the PAF also promotes production of high levels of antibodies, which could be helpful in fighting not only the spread of gum disease in those patients but other infections that might be caused when periodontal bacteria enter the blood stream and travel to major organs such as the heart.

“This is just one piece of the puzzle as we seek to understand not only the causes of periodontal disease in young people but also to understand the unusual immune responses in these patients,” Dr. Barbour says. “This does tell us that PAF is not just a bad thing because it causes inflammation.  It can be a good thing. We’ll need to balance this beneficial response with its pro-inflammatory effects.”

Barbour’s current experiments are aimed at further explaining the role PAF plays in the immune response in aggressive periodontitis in teens and young adults. 

Barbour is part of an interdisciplinary team that includes researchers from VCU’s Schools of Dentistry and Medicine and investigators from the National Institutes of Health who have been studying the biological and genetic aspects of gum diseases, particularly in teens and young adults, since the late 1970s. The work at VCU has resulted in the world’s largest database of information on young patients suffering from aggressive periodontitis and their families.