Author + information
Coronary artery ectasia (CAE) is defined as the abnormal dilation of coronary arteries. Neutrophil activation may contribute to the development of CAE. After activation, neutrophil granules are mobilized and secrete various products, including proteases, myeloperoxidase (MPO) and other proteins. Plasma levels of neutrophil serine proteases are elevated in CAE patients, which may destruct vascular walls and cause ectasia. Decreased intracellular MPO level as well as increased extracellular MPO level are recognized as markers of neutrophil activation. The aim of this study was to determine the activation status of circulating neutrophils in CAE patients.
Peripheral blood samples of 158 subjects were collected after angiography, 36 patients of which were with coronary artery ectasia (CAE), 81 patients were with coronary artery disease (CAD) and 41 subjects were with normal coronary arteries (CON). We measured the intra-neutrophil mean MPO index (MPXI) using the flow cytochemistry complete blood analyzer (ADVIA2120). The plasma MPO concentration was measured using enzyme-linked immunosorbent assay.
MPXI was comparatively decreased in CAE patients (CAE: 1.82±3.21, CAD: 5.81±3.63, CON: 5.65±3.08; P<0.01). CAE group had significant higher plasma MPO level, compared to CAD and CON groups (CAE: 10.82±8.33ng/ml, CAD: 2.86±1.65ng/ml, CON: 2.51±1.19ng/ml; P<0.01). MPXI was inversely correlated with plasma MPO level (Pearson correlation coefficient: -0.364, P<0.01). CAD and CON groups showed no significant differences in MPXI and MPO level (P=0.626; P=0.137, respectively). Neither MPXI nor plasma MPO level correlated with Markis Class (the topological extent of ectasia) among the CAE patients.
This study is the first to measure intracellular and extracellular levels of MPO to confirm the activation status of neutrophils in CAE patients. Peripheral neutrophils are activated and then various contents are released into plasma, which may exacerbate vascular wall degeneration. The underlying causative factors of neutrophil activation require further investigation.