Cleveland Clinic researchers have found that elevated levels of the enzyme myeloperoxidase (MPO) in the blood can serve as a predictor for future heart attacks among otherwise healthy individuals, years before they experience symptoms.
The research led by Stanley Hazen, M.D., Ph.D., Head of the Section of Preventive Cardiology & Rehabilitation at Cleveland Clinic and S Matthijs Boekholdt, M.D., Ph.D., Department of Vascular Medicine, Amsterdam, The Netherlands, appears in the July 10 issue of the Journal of the American College of Cardiology. The study examined MPO levels in a subset of subjects participating in the EPIC-Norfolk study, a community-based population study (n=25,663) of apparently healthy men and women a between 40 and 79 years old. “This study shows for the first time that testing for MPO levels in apparently healthy individuals can help identify those who are at risk of developing coronary artery disease or having heart attacks over the ensuing six-year period,” Dr. Hazen said. “MPO was able to help discriminate individuals at risk who would otherwise gone undetected by more widely used tests which examine the level of LDL and HDL cholesterol or C-reactive protein (CRP) in the blood stream, the generally accepted predictors of heart disease.” Previous work by Dr. Hazen and his team determined that High-Density Lipoprotein (HDL), the major carrier of “good” cholesterol in blood, becomes dysfunctional when myeloperoxidase (MPO), an enzyme present in white blood cells, inhibits HDL’s ability to keep cholesterol from building up in the artery walls. Dr Hazen’s group also previously showed that elevated levels of MPO in blood can signal that a person experiencing chest pains is in imminent danger of suffering a heart attack, needing revascularization or of dying. The new research suggests the potential for wider application of MPO levels as a predictor of heart disease and heart attacks among populations at lower risk and who are not yet exhibiting symptoms.(Source: Journal of the American College of Cardiology : Cleveland Clinic : July 2007)