(By Dr. Joseph D. Lim and Dr. Kenneth Lester Lim, BS-MMG, DDM, MSc-OI)
A PROTEIN which causes blood-clotting protein prevents bone loss from gum disease. That is, in mice.
The study, published in the journal Science, is based on animal and human data.
The study is significant because gum disease affects many people. Nearly half of Americans over age 30, and 70 percent of those 65 and older, are affected by the disease.
Periodontal or gum disease is a bacterial infection of the tissues supporting the teeth.
In its early stages, the disease causes redness and swelling (inflammation) of the gums. In advanced stages, called periodontitis, the underlying bone becomes damaged, leading to tooth loss.
The study was conducted by scientists at the National Institute of Dental and Craniofacial Research (NIDCR), a part of the U.S. National Institutes of Health (NIH).
The study, led by NIDCR investigators Dr. Niki Moutsopoulos and Thomas Bugge, Ph.D., found that the buildup of a protein called fibrin triggers an overactive immune response that damages the gums and underlying bone.
It suggests that suppressing the abnormal fibrin activity could prevent or treat gum disease and other inflammatory disorders marked by fibrin buildup, including arthritis and multiple sclerosis.
It has been known previously that periodontitis is partly caused by an overactive immune cell response. It was not known what causes the response, and how it caused tissue and bone damage – until now.
”Severe periodontal disease can lead to tooth loss and remains a barrier to productivity and quality of life for far too many Americans, especially those lacking adequate access to dental care,” said NIDCR Director Rena D’Souza, a dentist. “By providing the most comprehensive picture yet of the underlying mechanisms of periodontal disease, this study brings us closer to more effective methods for prevention and treatment.”
At sites of injury or inflammation, fibrin normally plays a protective role. It helps blood clots to form and activates immune cells to fight infection.
An overactive response with too much fibrin, however, has been linked with health problems, including a rare form of periodontitis due to a condition called plasminogen (PLG) deficiency.
In affected people, mutations in the PLG gene lead to fibrin buildup and disease at various body sites, including the mouth.
To explore the connection between abnormal fibrin buildup and periodontitis, the study looked at PLG deficiency in mice and analyzed human genetic data.
Like humans with the condition, PLG-deficient mice developed periodontitis, including periodontal bone loss and elevated levels of fibrin in the gums, the NIH said in a news release.
The mice’s gums were crowded with immune cells called neutrophils, which are also found at high levels in common forms of periodontitis. Neutrophils typically defend the oral cavity from harmful microbes. An excessive neutrophil response is thought to cause tissue damage.
To find out if fibrin was driving this overactive response, the researchers impaired its ability to interact with and bind to protein receptors on neutrophils. The weakened binding between fibrin and neutrophils completely prevented periodontal bone loss in PLG-deficient mice.
It also reduced bone loss in normal mice with a common, age-related form of periodontitis, suggesting that similar mechanisms were at play in both forms of the disease.
“This study suggests that fibrin can cause neutrophil immunity to shift from protective to damaging in certain circumstances,” said Dr. Moutsopoulos who credited Dr. Lakmali Silva for her research that led to the findings. Dr. Silva is a postdoctoral fellow and the study’s first author.
“This fibrin-neutrophil engagement may be a driver of periodontitis,” said Dr. Moutsopoulos.
The NIDCR is America’s leading funder of research on oral, dental, and craniofacial health. The NIH is the medical research agency of the United States. A part of the U.S. Department of Health and Human Services, the NIH includes 27 medical research institutes and centers investigating the causes, treatments, and cures for both common and rare diseases.
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Dr. Joseph D. Lim is the former Associate Dean of the College of Dentistry, University of the East; former Dean, College of Dentistry, National University; Past President and Honorary Fellow of the Asian Oral Implant Academy; Honorary Fellow of the Japan College of Oral Implantologists; and Honorary Life Member of the Thai Association of Dental Implantology. For questions on dental health, e-mail jdlim2008@gmail.com or text 0917-8591515.
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Dr. Kenneth Lester Lim, BS-MMG, DDM, MSc-OI, graduated Doctor of Dental Medicine, University of the Philippines College of Dentistry, Manila, 2011; Bachelor of Science in Marketing Management, De la Salle University, Manila, 2002; and Master of Science (MSc.) in Oral Implantology, Goethe University, Frankfurt, Germany, 2019. He is an Associate professor; Fellow, International Congress of Oral Implantologists; Member, American Academy of Implant Dentistry and Philippine College of Oral Implantologists. For questions on dental health, e-mail limdentalcenter@gmail.comi/PN
