Background: Myeloperoxidase (MPO) impairing endothelial functions. We investigated whether increasing concentration of myeloperoxidase (MPO) and inflammatory markers induce progression and incident acute coronary syndrome (ACS) in stable coronary artery disease (SCAD) patients. Therefore, the concentration of MPO, lipids, lipoproteins (apo(apolipoprotein) AI, apoB, lipoprotein associated phospholipase A2 (LpPLA2) level), inflammatory markers (high sensitivity C-reactive protein (hsCRP), tumor necrosis factor-alpha (TNF-alpha), interleukine-6 (IL-6) concentration) were examined. Methods: This study concerned 67 SCAD patients divided into groups: all patients, patients with MPO < 200 ng/ml, MPO 200-300 ng/ml, MPO > 300 ng/ml concentration and 15 controls. ApoAI, apoB and hsCRP levels were examined using the immunonephelometric method, and MPO, LpPLA2, IL-6, TNF-alpha concentration was performed by using Quantikine ELISA kit R& D Systems. Results: In the all patients, and in group with MPO 200-300 ng/ml TC, LDL-C, nonHDL-C, LpPLA2 concentration and TC/HDL-C, LDL-C/HDL-C ratios were insignificant, and significantly higher concentration of TG, apoB, MPO, inflammatory markers and TG/HDL-C, MPO/apoAI, MPO/HDL-C ratios but HDL-C, apoAI level and HDL-C/apoAI ratio were significantly reduced. In the group of patients with MPO < 200 ng/ml, level of TC, LDL-C, nonHDL-C, apoAI, apoAII, LpPLA2 and MPO and LDL-C/HDL-C ratio were in-significant, HDL-C was decreased but apoB, TG, inflammatory markers, apoB/apoAI, TG/ HDL-C, MPO/apoAI, MPO/HDL-C ratio were significantly increased. In the group of patients with MPO > 300 ng/ml concentration of TC, LDL-C, nonHDL-C, apoAII, LpPLA2 and LDL-C/HDL-C ratios were not significant, but HDL-C and apoAI concentrations were significantly decreased. The concentrations of TG, apoB, MPO and inflammatory markers and TG/HDL-C, MPO/apoAI, MPO/HDL-C ratios were significantly increased compared to the controls. The apoAI concentration was significantly decreased and the concentration of MPO and hsCRP as well as MPO/apoAI and MPO/ HDL-C ratios were significantly higher as compared to the group of patients with MPO < 200 ng/ml. Spearman's correlation test showed a positive correlation between MPO concentration and MPO/apoAI and MPO/HDLC ratios in all patients and MPO < 200 ng/ml, MPO 200-300 ng/ml. The patients with MPO > 300 ng/ml showed a positive correlation between the concentration of MPO and the level of hsCRP and IL-6, and a negative correlation between MPO/apoAI ratio and the concentration of HDL-C, apoAI and apoAII. Conclusion: The results suggest that moderate dyslipidemia and dyslipoproteinemia deepening of inflammation, and inflammation slowly induce increase MPO concentration which decrease apoAI and HDL-C level and disturb HDLs function. The increasing MPO level and MPO/HDL-C, MPO/apoAI ratios can differentiate the SCAD patients at the risk of acute coronary syndrome (ACAD) and stroke.
