( A molecule that usually protects the bo...)Molecule that usually protects infection-fighting cells may cause plaque deposits inside arteries

The molecule, called apoptosis inhibitor of macrophage or AIM, inhibits cell death in macrophages, which circulate in the bloodstream and help the body fend off infection and foreign substances. The AIM-protected macrophages go on to encourage buildup of fats on the interior walls of arteries, according to Dr. Toru Miyazaki, senior author of a study that appears in the March issue of the journal Cell Metabolism.

"We found that AIM is highly expressed in certain macrophages and that lack of AIM dramatically decreased early atherosclerotic lesion development in mice," Dr. Miyazaki said. "These results may imply a novel therapeutic application of AIM regulation for prevention of atherosclerosis in the future. Most importantly and attractively for patients, this approach may not need dietary restriction."

Dr. Miyazaki, associate professor in the Center for Immunology and of pathology, and his colleagues first discovered the protective role of AIM six years ago. In the current study, scientists exposed mice lacking AIM to a fatty diet that would normally induce atherosclerosis.

After several weeks, researchers found little to no atherosclerotic lesions. Comparatively, in mice that had normal AIM function, there was marked presence of plaque deposits in the arteries following a diet of high-fat food.

"This was dramatic evidence that showed suppressing AIM function translates into prevention of atherosclerosis," Dr. Miyazaki said.

Atherosclerosis, known as "hardening of the arteries," occurs when the inside walls of an artery become thicker and less elastic.

This narrows the space for blood flow and can lead to angina and heart attacks in some people. Fatty buildups occur on the inner lining of an artery and grad
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Source:University of Texas Southwestern Medical Center at Dallas