Abstract 11588: Inverse Correlation between Plasma Myeloperoxidase Levels and Serum High-Density Lipoprotein-Associated Paraoxonase-1 Levels in Patients with Stable and Unstable Coronary Artery Disease
Background: High-density lipoprotein (HDL) cholesterol is well-established as a negative risk factor for coronary artery disease (CAD) and its anti-oxidant property has been attributed mainly to the HDL-bound enzyme paraoxonase-1 (PON-1). Recently, myeloperoxidase (MPO), a pro-oxidant enzyme released from activated neutrophils, has been shown to reverse the atheroprotective action of HDL. The aim of this study was to investigate the relationship between plasma MPO and serum PON-1 levels in patients with stable (SAP) and unstable angina pectoris (UAP).
Methods: Plasma MPO and serum PON-1 concentrations and activity were measured in patients with SAP (n=230) and UAP (n=151), and in control subjects (n=102).
Results: Plasma MPO levels were significantly higher in UAP patients than in SAP patients or control subjects (UAP, 21.6 [16.7-44.6]; SAP, 19.2 [15.6-29.1]; control, 16.0 [14.8-18.9] ng/ml; P<0.0001). Furthermore, serum PON-1 concentrations were significantly lower in UAP and SAP patients than in control subjects (UAP, 55.6 [45.9-69.7]; SAP, 55.0 [46.9-64.9]; control, 62.1 [50.8-78.0] μ g/ml; P<0.0001). Serum PON-arylesterase activity in patients with UAP was also significantly lower in UAP and SAP patients than in control subjects (UAP, 131 [111-165]; SAP, 131 [107-153]; control, 124 [102-152] μ mol/min/mL; P<0.05). Plasma MPO levels showed a weak inverse correlation with serum PON-1 concentrations (r = - 0.176, P<0.0001) and PON-arylesterase activity (r = - 0.181, P<0.0001) in all subjects. Moreover, plasma MPO levels showed a significant inverse correlation with serum PON-1 concentrations and PON-arylesterase activity in female SAP (PON-1 concentration: r = - 0.362, P<0.01; PON-arylesterase activity: r = - 0.333, P<0.05) and UAP patients (PON-1 concentration: r = - 0.340, P<0.05; PON-arylesterase activity: r = - 0.350, P<0.05), but not in male SAP or UAP patients.
Conclusions: This study suggests that MPO and PON-1 levels may demonstrate sex-specific differences in the risk of coronary artery disease, and that an imbalance between pro-oxidants and anti-oxidants may contribute to the progression of coronary plaque instability.
- © 2011 by American Heart Association, Inc.