7/24/2007 - Blood protein could be early sign of heart disease High levels of a blood protein might signal an increased risk for heart disease in people who appear healthy, a preliminary study suggests. And these high protein levels may be present years before heart disease can be detected by traditional means. The study, part of a community-based research program called European Prospective Investigation Into Cancer and Nutrition (EPIC), appears in the July 10, 2007, issue of the Journal of the American College of Cardiology. Myeloperoxidase (MPO) is a protein secreted by white blood cells that kills harmful bacteria. But researchers believe that MPO may also inflame the arteries and release a bleach-like substance that causes cell death and erosion of the arterial lining. This process may also cause unstable plaque in the arteries. In addition, MPO may hamper the protective effects of HDL cholesterol and nitric oxide on the arteries. Previous studies have found high MPO levels in people who had chest pain and heart disease. However, this is the first large-scale study to examine the relationship between MPO and cardiovascular disease risk in healthy people, said lead researcher Matthijs Boekholdt, M.D., Ph.D., a resident in cardiology at Academic Medical Center in Amsterdam, the Netherlands. Between 1993 and 1997, researchers recruited healthy people from Norfolk, United Kingdom, as part of the EPIC study. Baseline blood samples were taken from each person for future analysis. After about eight years of follow-up, 1,138 of the people had either been admitted into the hospital or died from development of coronary artery disease (CAD), including heart attack. Researchers compared these people with participants who remained healthy throughout the follow-up period. They found that average blood levels of MPO were significantly higher in people who developed heart disease than in those who stayed healthy. Researchers also divided people into four groups based on their MPO levels. They found that people with the highest levels were 1.49 times more likely to develop CAD or have a heart attack than those with the lowest levels. High levels of MPO even signaled an increased risk for heart trouble in people who didn't have traditional risk factors for the disease, such as high levels of LDL cholesterol. As researchers continue to assess the value of MPO in different groups of people, Dr. Boekholdt said some main issues to consider include whether or not checking MPO levels should be added to screening tests for cardiovascular disease and if blocking MPO could prevent cardiovascular disease. "This could open up completely new areas of research and diagnosis," said Dr. Boekholdt. "As we learn more about these processes, we hope to be able to identify 'vulnerable blood' as a reliable tool for detecting vulnerable patients." Back