Systemic Active and Total Myeloperoxidase Levels in Coronary Artery Disease.

Backgound: Measurement of total Myeloperoxidase (MPO) by ELISA is considered as a marker of neutrophil activation but is not the true indicator of the degree of its activity.
In a dynamic pathology such as atherosclerosis, it may be important to measure the real active part of MPO because it represents the true witness of the oxidant potential of the enzyme.
Aim: To identify the relation between coronary artery disease identified by coronaro-angiography on measured serum total and active MPO levels and evaluate the correlation between these MPO levels and the presence of clinically defined unstable condition.
Methods: Prospective analyse of serum samples of patients before (within 30 min) coronaro-angiography. Total and active MPO concentrations were assessed by sandwich Elisa and SIEFED® method’s respectively.
Results: Two hundred and twenty patients were included in this study (age: 66.1±10.7 years, 67% of male). Among these, 62% presented significant coronary artery disease (stenosis more than 60% at least in one épicardial coronary artery). Twenty four patients (11%) presented unstable coronary syndrome.
Mean active and total MPO in the general population were 50.1±63.5 and 147.6±223.3 ng.mL-1 respectively. In comparison, mean active MPO was 47.1±47.9 ng.mL-1 in stable patients and 75.1±135.2 ng.mL-1 in unstable patients (p=0.04). Mean total MPO was 146.3±224.7 ng.mL-1 in stable patients and 158.2±215.8 ng.mL-1 in the unstable’s one (p=0.8). There was a significant correlation between active MPO levels and instability (r=0.14, p=0.04) not present for total MPO levels (r=0.016, p=0.8).
Conclusion: We observed a correlation between active MPO and clinical instability while there was no correlation with total MPO. Our preliminary results suggest that this marker could be a powerful indicator of instability which could possess an important prognostic impact. This hypothesis requires an evaluation in wider population and during a prolonged follow-up.