Lack of association between plasma myeloperoxidase levels and angiographic severity of coronary artery disease in patients with acute coronary syndrome

Myeloperoxidase activity and acute coronary syndrome survival: long-term evaluation in the ERICO study

AIM

We aimed to analyze the influence of myeloperoxidase (MPO) activity on mortality in the Acute Coronary Syndrome Registry Strategy (ERICO) study.

METHODS

MPO activity levels were evaluated in 342 patients. We performed survival analyses using Kaplan-Meier curves and Cox regression with respective hazard ratios, 95% CI, according to MPO tertiles distribution up to 7 years of follow-up.

RESULTS

Higher MPO activity levels were seen in men, smokers, diabetics and those who were taking aspirin. MPO activity levels were neither significant in relation to mortality nor to survival rates up to seven years.

CONCLUSION

We found no relationship between elevated levels of MPO activity post-acute coronary syndrome and mortality up to 7-years of follow-up in the ERICO study.

Association between serum myeloperoxidase levels and coronary artery disease in patients without diabetes, hypertension, obesity, and hyperlipidemia

Background:

Myeloperoxidase (MPO) is an enzyme, elevated in the atheroma and serum of a patient with atherosclerotic vessels. The aim of this study is to investigate whether the serum MPO level is related to the presence of plaque in patients without risk factors, such as, diabetes, hypertension, obesity, and hyperlipidemia.

Materials and Methods:

A serum sample was collected from patients who referred for angiography. The MPO level was measured in the serum samples of 40 patients without risk factors for atherosclerosis using the enzyme-linked immunosorbent assay (ELISA).

Results:

The MPO level was 245.5 ± 13.8 (ng/ml) in patients with atherosclerosis and 213.9 ± 8.9 (ng/ml) in patients without atherosclerosis. There was a significant difference between the groups (P = 0.002). The odds ratio was 0.67 (0.95 CI, 0.17 – 2.5) for patients with and without coronary atherosclerosis.

Conclusion:

Although the MPO concentration is higher in patients suffering from atherosclerosis, it is not a predictor of coronary artery disease in patients without diabetes, hypertension, obesity, and hyperlipidemia.

Myeloperoxidase may help to differentiate coronary plaque erosion from plaque rupture in patients with acute coronary syndromes

Coronary thrombosis is the most frequent final event leading to an acute coronary syndrome. In approximately two-thirds of cases, the thrombus overlies a ruptured plaque, whereas in one-third of cases it overlies an intact plaque with superficial endothelial erosion, a finding showed initially by histopathological postmortem studies and more recently confirmed by in vivo optical coherence tomography imaging. Interestingly, recent observations suggest that mechanisms leading to plaque rupture or erosion are different. In fact, in a recent study, we showed that myeloperoxidase levels in peripheral blood and expression within thrombi overlying the culprit plaque are much higher in patients with plaque erosion than in those with plaque rupture. These observations suggest that innate immunity activation is likely to play a key role, in particular, in plaque erosion and might become a therapeutic target in this subset of patients.