Mapping Molecular Pathways
 Salomon Amar: Linking Inflammation to Systemic Disease
Millions of Americans are afflicted by cardiovascular disease which can lead to life-threatening events like stroke and heart attack. Most people agree that exercising and eating right can reduce the risk of developing heart disease, but what about tooth brushing, flossing, or treating gum infections? Oral biologist Salomon Amar says that treating an infection, whether it’s herpes, pneumonia, or gum disease, may be one route to lower the risk of systemic diseases like heart or pulmonary disease.
Epidemiological studies have suggested a link between atherosclerosis (hardening of the arteries) and severe periodontal disease (a chronic bacterial infection of the gums). Evidence from Amar’s lab supports this hypothesis, indicating that infection causes an inflammatory response in the body which may trigger systemic diseases such as atherosclerosis. This line of research has enormous implications for dental health care. “People will take better care of their teeth if they know it can prevent heart disease,” says Amar.
 In earlier research, Amar had shown that people with severe gum disease often have dysfunction of the endothelium lining blood vessels, a sign of cardiovascular trouble. He also found higher levels of disease markers in their blood plasma, including the bacteria themselves, their by-products, or inflammatory mediators produced in response to the bacteria entering the bloodstream. “But,” says Amar, “if you treat the infection you drastically reduce the chance of developing systemic disease.”
To test whether treating gum infection might reduce evidence of heart disease, Amar gathered a group of eight people with periodontal disease and treated them with scaling, root planing, and surgery. He found drastic improvement in the function of endothelial cells lining blood vessels and less inflammation in all the subjects who received intensive periodontal treatment. Amar is currently conducting a phase II/III clinical trial to confirm these findings in a larger group of subjects.
 Aware that the progress from infection to inflammation and systemic disease is not an isolated one, Amar is now studying obesity, a condition that may complicate the pathway. In new study results, he found that obese animals were incapable of mounting an adequate immune response to infection, produced lower levels of immune chemicals to fight infection, and had infections that lasted longer, potentially harming healthy cells. In addition, he found that the activity of enzymes, such as kinases, known to be critical to the molecular pathways that respond to inflammation, were dysfunctional in obese animals. These results suggest that obesity may be a factor in reducing an organism’s ability to fight infection and potentially play a role in chronic infection, systemic disease, and lower quality of life.
Amar is planning a clinical trial that will compare immune responses in patients with a normal body mass index (BMI under 25) and obese subjects (BMI over 35). He hopes that by further elucidating obesity’s role in the pathway that leads from infection to systemic disease he may also help explain why obesity poses such a danger to overall health.
For more information, visit http://dentalschool.bu.edu/Research/perio/amar.htm.
— by Leah Eisenstadt |
