An experimental vaccine may help fight artery-clogging plaque (search) and keep arteries clear and healthy, according to a new study.

Researchers found vaccinating laboratory mice against a chemical messenger secreted by the immune system, known as interleukin 12 (IL-12), reduced plaque buildup along artery walls by 68 percent. The mice used in the experiment were bred to develop atherosclerosis plaque in the arteries.

If further studies confirm these results, researchers say the vaccine may become “a promising strategy for the treatment of atherosclerosis."

Atherosclerosis, or hardening of the arteries, occurs when plaque builds up along the artery walls and restricts blood flow. When this plaque becomes fragile and ruptures, parts of the plaque can break off and dislodge and completely block arteries causing heart attacks or strokes. Studies have shown inflammation to be important in heart disease.

A Vaccine for Atherosclerosis?

In the study, researchers tested the effects of vaccinating mice against interleukin 12, which is thought to play a key role in atherosclerosis and other diseases that affect the immune system. The chemical messenger (IL-12) triggers the production of other chemicals in the blood known as cytokines that are believed to help stimulate plaque deposits.

Researchers found the vaccine blocked the actions of interleukin 12 in mice.

Two weeks after vaccination, the mice had 68 percent less plaque formation in their arteries compared with mice that didn’t get the vaccine. In addition, the vaccinated mice had 58 percent less narrowing of the arteries caused by plaque.

Researchers say the vaccine not only reduced the size of plaque deposit, but it also changed the composition of the plaque, making it more stable and less capable of dislodging, which may have a beneficial effect in the treatment atherosclerosis.

The results of the study were presented this week at the American Heart Association’s Scientific Sessions 2004 in New Orleans.

By Jennifer Warner, reviewed by Brunilda Nazario, MD

SOURCES: Hauer, A. “Vaccination against Interleukin 12 Attenuates Atherosclerosis in LDL Receptor-Deficient Mice,” presented at the American Heart Association’s Scientific Sessions 2004, Nov. 7-10, 2004, New Orleans. News release, American Heart Association.