Open wide. A recent study by Sok-Ja Janket, an SDM assistant professor in general dentistry, shows strong evidence of a connection between poor oral health and coronary heart disease. The results support earlier clinical studies at SDM that link gum disease with atherosclerosis, the hardening of the arteries associated with heart disease and stroke.

Janket compared the oral health of 500 patients; half were diagnosed with cardiac disease. An asymptomatic dental score (ADS) was assigned to each patient, based on ranked assessments in five categories: pericoronitis (infection around the third molar), gingivitis (gum inflammation), missing teeth, root remnants (remains of decayed teeth), and dental caries (decay). Of those with high ADS scores, 70 percent had coronary heart disease — pericoronitis was the strongest predictor, followed by root remnants and gingivitis.

Overall, ADS predicted heart disease better than other standard markers, such as high levels of fibrinogen (a clotting protein), low HDL cholesterol, or high triglycerides. In the study, coronary heart disease could be predicted with 82 percent accuracy when these markers were combined with ADS scores.

Although the study suggests that there is a close association between oral health and coronary heart disease, it does not indicate that one causes the other, says Janket. She hypothesizes that while inflammation may be a factor, nutrition may also play a role. “People who do not have teeth cannot chew their food well,” she says, “and therefore do not get as much heart-healthy nutrients or fiber.”

Janket recommends that dentists encourage patients with poor oral health to have a cardiac evaluation, even if they do not have symptoms of heart disease.

This study was published online on February 16, prior to publication in Circulation: The Journal of the American Heart Association.

Fooling Mother Nature. Each year, more than one million new cases of skin cancer occur in the United States, comprising more than 40 percent of all malignancies. Skin cancer is clearly linked to ultraviolet (UV) radiation from the sun, but such factors as fair skin, genetic predisposition, and advanced age increase an individual’s likelihood of developing it.

Researchers at the School of Medicine may have found a novel way to protect skin from the harmful effects of sunlight, which include photoaging as well as cancer. “Tricking” cells into believing they have suffered DNA damage triggers them to activate natural defense mechanisms that will protect against future damage.

The research team, led by Barbara Gilchrest, a MED professor and chairman of the department of dermatology, and David Goukassian, a MED research assistant professor of dermatology, applied a DNA fragment known as thymidine dinucleotide (pTT) to the skin of specially bred hairless mice over several months. The treated mice, as well as a group of control mice that did not receive pTT, were later exposed to an amount of UV radiation expected to cause skin cancers. After six months, 78 percent of the treated mice remained cancer-free, compared to 12 percent of the control animals. Moreover, tumors in the pTT-treated mice took 16 weeks to start developing, compared to 9 weeks in the control animals.

The researchers had previously shown that cultured cells exposed to pTT responded by increasing their levels of DNA repair proteins as if they had been damaged. The current study is the first to test the effectiveness of the DNA fragment applied to the skin of animals.

According to Goukassian, pTT enters the nucleus of the skin cells, mimics the DNA damage signal, and initiates production of DNA repair enzymes. Later, when the skin is actually exposed to UV, the enzymes are already in place and ready to repair the damage. In people and in animals that tan, such as guinea pigs, pTT also induces tanning, which further protects the skin from DNA damage.

Although much research remains to be done, Gilchrest says, the work suggests that it may be possible to create a topical product containing DNA fragments that will safely promote tanning and protect people from sun damage and skin cancer.

This research was reported in the March 1 issue of the Proceedings of the National Academy of Sciences..