The biological process by which smokeless tobacco injures the mouth has been identified by a group that includes three researchers at the University of Illinois at Chicago College of Medicine. Their findings were published in the Nov. 15, 1996 issue of The Journal of Immunology.
Dr. Israel Rubinstein, UIC associate professor of medicine, and his colleagues have "identified key mechanisms of how smokeless tobacco damages the mucous membrane of the oral cavity in laboratory animals," according to Rubinstein.
In hamster studies, they determined for the first time that exposure to smokeless tobacco makes blood vessels in the mouth leaky leading to inflammation. They found that this exposure produces bradykinin, a potent pro-inflammatory peptide. At the same time, they found that smokeless tobacco decreases the activity by an enzyme that can neutralize bradykinin in the mouth -- angiotensin-converting enzymes (ACE).
Because the chemical composition of smokeless tobacco is complex, the researchers say it is difficult to identify a single component, such as nicotine, that elicits bradykinin production and decreases ACE activity in the mouth. They say more studies are needed to identify the specific components of smokeless tobacco that cause small blood vessels in the cheek to become leaky.
"Obviously, the best way to prevent injury from smokeless tobacco is not to use it," says Rubinstein. "But for those who can't or won't quit, it's important that we have these new insights into the injurious effects of smokeless tobacco in the mouth. They may eventually lead to the development of new ways to treat these lesions."
Rubinstein's collaborators on this study were Dr. Xiaopei Gao, UIC research assistant professor of medicine, Dr. Christopher Olopade, UIC assistant professor of medicine, Jamboor Vishwanatha of the University of Nebraska and J. Michael Conlon of Creighton University.
Consumption of smokeless tobacco is on the rise in the United States, particularly among high school students. According to the U.S. Department of Agriculture, smokeless tobacco consumption increased from 30 million pounds in 1981 to more than 50 million pounds in 1991. A 1995 Centers for Disease Control survey of high school students nationwide found that 11 percent of teens use smokeless tobacco. Its use can lead to mouth lesions, inflamed gums and, in the worst case, oral cancer.