According to the American Heart Association (AHA), cardiovascular disease (CVD) is the number one killer of Americans --- and far too frequently the first sign of CVD is heart attack, stroke or death. In research presented today at the AHA's Scientific Sessions in New Orleans, Emory scientists say an enzyme produced by white blood cells in response to inflammation may reveal hidden, or subclinical, CVD.
Oxidative stress, which is associated with the pathogenesis of multiple disorders including heart disease, results from an imbalance between free radical production and the antioxidant cascade. Myeloperoxidase (MPO), a leukocyte enzyme that induces oxidation, is known to be elevated in CAD patients and is believed to play a role in the development of CAD. An Emory University School of Medicine team headed by Emory Heart Center scientist Viola Vaccarino, MD, PhD, worked with the Vietnam Era Twin Registry of Seattle, Washington, to research whether MPO is also a marker of subclinical CAD.
The Emory researchers studied 104 male twins between the ages of 47 and 57 (participants in the ongoing Twins Heart Study) who had no clinical symptoms of CAD. Positron emission tomography (PET) images were used to detect otherwise hidden CAD.
"We found myocardial perfusion defects, indicating CAD, in 36 individuals (35 percent). There was a strong and graded association between increased levels of MPO and the number of PET perfusion defects," says Dr. Vaccarino, who headed the study. "This association persisted after we adjusted for age, systolic blood pressure, body mass index, smoking, and cholesterol levels."
This study is the first evaluation of MPO as a marker of subclinical CAD in individuals with no obvious cardiovascular disease symptoms. "Although it is still too early to recommend MPO measurement as a risk stratification tool, our results support the notion that MPO may be an early marker of CAD. Our data also support the notion that oxidative stress is important in the development of cardiovascular disease," says Dr. Vaccarino.