Fat-Storing Protein: A Diagnostic Tool for Heart Attack, Stroke Risk?

A protein that helps body cells store fat could help physicians assess whether patients whose blood vessels contain fatty deposits called plaque are at risk for a heart attack or stroke.

Researchers found evidence that the protein--perilipin--was more actively synthesized in ruptured plaque than in stable plaque. When plaque ruptures, it triggers formation of a plug--an internal “scab”--that can stop blood flow in the artery or reduce it to a trickle. If the ruptured plaque is in the heart, it could cause a heart attack; if in the neck or head, a stroke could ensue.

Andrew S. Greenberg, a research physician at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, collaborated on the study with a group of researchers at the University of Maastricht in The Netherlands. The Boston center is funded by the Agricultural Research Service, USDA’s chief scientific research agency.

The Dutch researchers, led by Mat J.A.P. Daemen, wanted to know if certain genes are more active--that is, expressed as proteins--in ruptured plaque. They sought collaboration with Greenberg, an expert in perilipin. The researchers cloned genes from ruptured and nonruptured plaque and looked for differences in expression among the genes.

According to Greenberg, there was good evidence that the perilipin gene was turned on and expressing the protein in the ruptured plaques, whereas it was difficult to detect any expression in stable plaques. The findings were published in Circulation Research last September.

Greenberg foresees several applications of the team’s finding. First, a test for the presence and amount of perilipin could be developed to detect plaque in danger of rupture. For instance, a perilipin antibody, which would attach to the protein, could be tagged with a radioactive tracer and “seen” with imaging technology. Such a test could be used to monitor the effectiveness of nutritional interventions, such as folate or antioxidants, on risk for heart attack or stroke.

Moreover, the discovery will help researchers better understand how plaques become unstable, and it could lead to preventative measures.