One more link has been forged between poor oral health and heart disease as findings from two research studies from Case Western Reserve University's School of Dentistry were presented during the 32nd annual meeting of the American Association of Dental Research in San Antonio, Texas.

In the first study ("CRP Levels and Bacterial DNA Presence in Patients with Coronary Artery and Periodontal Diseases"), Nabil Bissada, CWRU chair of the department of periodontics, told more than 300 session attendees that a team of researchers looked at c-reactive protein (CRP) levels in 50 individuals to see if it correlated with periodontal disease and the most severe form of heart disease within the study group. The study also examined the presence of bacterial species of gum diseases in the blood before and after the same patient underwent cardiac catherization.

"The Identification of P. gingivalis LPS and IL-1_ in Atheromatous Plaques of Coronary Arteries" was the second study. It was conducted in collaboration with the Cuyahoga County's Coroner's Office. Families of 15 deceased individuals gave researchers permission to take tissue samples from the blood vessels of the heart, abdomen, kidneys and liver within 24 hours of death to examine the tissues for the presence of bacterial DNA and their endotoxins that cause chronic periodontitis, one of the most common forms of gum disease.

First study's results

All 50 individuals in the first study had exhibited some symptoms of coronary heart disease from chest pains, shortness of breath or a failed stress test. These individuals were divided into two groups of mild or severe angina.

The group again was divided into those with mild or severe periodontitis. Researchers ran a correlation between heart and gum disease and found that those in the severe angina group had a severe form of periodontal disease.

Bissada said that those individuals with severe cardiovascular disease and severe periodontitis also had eight times higher a chance of having elevated CRP levels over the mild groups. This was after the adjustment for such factors as cholesterol, glucose, triglycerides, diabetes and smoking. After adjusting for gender, age and ethnicity the severe angina/periodontitis group had CRP levels six times higher than the mild angina group.

CRP has become a marker for potential heart disease and is present in higher concentrations in the blood where there is a chronic inflammatory disease such as periodontitis. This research has a 95 percent level of confidence.

Each of the patients also underwent catherization procedures where blood and dental plaque samples from the gums and teeth were taken before, with another blood test five minutes after the catherization balloon was removed and a stent placed. While blood samples showed no detectable bacteria prior to the catherization in some patients, the presence was noted following it to suggest that the oral bacteria is in the lesions of the heart blood vessels, according to Bissada.

Other project researchers were Rebecca Davis, CWRU; Dennis DeLuca; Aaron Weinberg, CWRU periodontics department; and Ravi Nair, University Hospitals of Cleveland Division of Caridiology .

Second study's results

The second study further examined the invasiveness of the P. gingivalis (P.g.) and endotoxins into the endothelial and smooth muscles of the coronary arterial cells and to examine the level of Interleukin-1a (IL-1a.) that indicates inflammation because of infection.

The researchers examined tissues from the blood vessels of heart, liver, stomach and kidneys for the presence of P.g.'s DNA and endotoxins. The DNA of P.g. was detected in 47 percent of the coronary arteries examined, and IL-1a was found in 93 percent. Both are rarely detected in the blood vessels of the other organs.

"This study gives some explanation as to why some people have sudden heart attacks even though they exercise, are not smokers and do not have high cholesterol levels," said Bissada. "Something in the coronary arteries attracts P.g."

Susan Nguyen, Deluca, Weinberg and Thomas McCormick, CWRU assistant professor of dermatology, also worked on this study.