Myeloperoxidase, Subclinical Atherosclerosis, and Cardiovascular Disease Events

Division of Cardiology, University of California, Irvine, California, USA.
JACC. Cardiovascular imaging (Impact Factor: 7.19). 09/2009; 2(9):1093-9. DOI: 10.1016/j.jcmg.2009.05.012
Source: PubMed


We evaluated whether myeloperoxidase (MPO) predicts future cardiovascular disease (CVD) events in asymptomatic adults and whether subclinical atherosclerosis may affect this relation.
Myeloperoxidase is a leukocyte-derived enzyme-generating reactive oxidant species that has been shown to predict risk of CVD in selected populations.
We studied 1,302 asymptomatic adults (mean age 59 years, 47% women) without known CVD who were followed for 3.8 years. We measured MPO by the use of immunoassay. Coronary artery calcium (CAC), a measure of subclinical atherosclerosis, was measured by computed tomography with the Agatston score categorized as none/minimal (0 to 9), mild (10 to 99), and moderate/significant (> or = 100). Cox regression, adjusted for age, sex, and other risk factors, examined the relation of CAC and/or MPO with incident CVD events.
Persons with MPO levels at or above compared with below the median (257 pM) were more likely (p < 0.05 to p < 0.001) to be women, have a higher body mass index, greater low-density lipoprotein cholesterol, greater systolic and diastolic blood pressure, and lower high-density lipoprotein cholesterol. Mean MPO levels increased according to CAC categories (p trend = 0.02). Incident CVD events were more likely in those at or above versus below the median MPO level (4.6% vs. 2.3%, p = 0.02), even after adjustment for age, sex, CAC, and risk factors (hazard ratio [HR]: 1.9, 95% confidence interval: 1.0 to 3.6, p = 0.04). Combining CAC and MPO categories, CVD incidence ranged from 0.6% in those with a CAC score of 0 to 9 to 7.1% (adjusted HR: 9.2, p < 0.001) in those with CAC scores of > or = 100 and MPO below the median and 14.0% (adjusted HR: 19.5, p < 0.0001) in those with CAC scores of > or = 100 and MPO at or above the median.
Our study suggests persons with both increased levels of both MPO and CAC are at an increased risk of CVD events. Imaging of subclinical atherosclerosis combined with assessment of biomarkers of plaque vulnerability may help improve CVD risk stratification.

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Available from: Heidi Gransar, Jan 15, 2015
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    • "Another study included 1,302 asymptomatic adults (mean age 59 years, 47% women) without known CVD who were followed for 3.8 years. After measuring MPO and coronary artery calcium, by computed tomography, the study suggested that persons with both increased levels of both MPO and CAC are at an increased risk of CVD events [189]. However, the concentration of MPO depends on the assay method, sampling material, and preanalytical and analytical procedures. "
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    • "This effect of leucocytes on vascular function may be physiological under states of acute infection and sepsis, in which the secreted MPO provides a sink for the excess synthesis of NO provided but may be detrimental under conditions of chronic vascular disease such as atherosclerosis, in which diffuse MPO sequestration into the vessel lumen may lead to oxidation of endothelium-derived NO thereby pathologically increasing vascular tone. Thus the current studies reinforces observational studies in humans with MPO deficiency indeed being characterized by a reduced occurrence of cardiovascular disease,31 whereas increased levels of MPO were indicative of cardiovascular disease in asymptomatic individuals.32,33 "
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