| Backrounds: Studies on the mechanism and identification of vulnerable plaques are important to the prevention of acute coronary syndrome (ACS). Studies have demonstrated that inflammatory reaction played a key role in the development of ACS. Tests of circulatory inflammatory factors, such as high sensitive c-reactive protein (hsCRP), have been used to screen for those who have the risk of developing cardiac events. Another popular method is to examine the changes of the transcoronary factor concentrations (i.e. differences among those in coronary sinus and those in the root of aortic artery), which might reflect inflammation of the local plaques, and thus provide a thorough evaluation of the coronary artery beds. There were studies showing greatly increased infiltrations of neutrophils and macrophages, and expressions of inflammatory factors in the unstable plaques. Therefore, the association of neutrophil-mediated inflammatory reaction with the vulnerable plaques gives rise to attentions. Lately, neutrophil-released enzyme- myeloperoxidase (MPO) attracted attentions as a marker of neutrophil activation. MPO not only participates in the inflammatory reactions, but also plays a principle role in the oxidation of LDL by its catalyzed product- cheese-acyl free radical. The importance of oxidized -LDL (OX-LDL) in the pathogenesis of atherosclerosis has been well established.Objectives: The aims of this study were to: (1) make clear the changes of peripheral venous blood concentrations of MPO in patients with stable angina pectoris, unstable angina pectoris and acute myocardial infarction; (2) elucidate the differenceof MPO blood concentrations between the systemic circulation and the coronary circulation among patients with stable angina pectoris .unstable angina pectoris and acute myocardial infarction; (3) try to illustrate the relationship between MPO and low density lipoprotein.Methods : Subjects : From Dec.2002 to Jan.2004,altogether 91 cases of hospitalized patients who underwent coronary angiography were included in this study. They were divided into 4 groups: (1) Patients with acute myocardial infarction (AMI) were 19 cases, 12 of them were male, and 7 were female. The average age was 58.25 ±9.74 years old. All of them demonstrated ST elevation on electrocardiogram and were within 7-10 days of onset. (2) Patients with unstable angina pectoris (UAP) were 30 cases, 18 of them were male, and 12 were female. The average age was 58.73 + 7.81 years old; (3) Patients with stable angina pectoris (SAP) were 22 cases, 10 of them were male, and 12 were female. The average age was 58.73 + 7.81 years old; (4) The controls were 20 cases, 9 of them were male, and 11 were female. The average age was 50.35 ±8.31 years old. Their angiographic images were normal. Methods: Angiography was performed according to the regular procedure. The numbers of coronary arteries with lesions were recorded. Those lesions resulting in more than 50 percent of stenosis were grouped into 2 types. Type I: Concentric or eccentric lesions with smooth surface and wide base. This was defined to be stable plaque. Type II: Lesions with narrow base, or sharp angular lesions, or ulcerative lesions with niche, or with irregular surface like volcano; Type II were defined to be unstable plaque. A 5F Simmonll catheter was put into the coronary sinus before angiography through the femoral vein. All the subjects were taken 7 ml of blood from the femoral vein, in the mean while, 10 cases of AMI, 20 cases of UAP, 10 cases of SAP and 10 cases of the controls were taken 7ml of blood from the root of aortic artery and the coronary sinus respectively. The in-gate percentage and the average fluorescent intensity of MPO were examined with flow cytometry; hsCRP was measured by means of particle enhancement nephelometery; LDL was measured with Auto Biochemistry Analyzer; The ultra-structures of leukocyte were observed through transmission electroscope.Results: (1) Comparison of general data: no difference existed among the 4 groups in age and sex, and no difference existed among the 3 groups with coronary artery disease in hypertension, blood glucose level, blood cholesterol level, and history of smoking; (2) Comparison of the lesions: the amount of the victim coronary arteries were greater in the UAP and SAP patients than that in the AMI patients (2.17 + 0.79 vs 1.70 + 0.80, PO.05; 2.13 + 0.77 vs 1.70 + 0.80, P<0.05),There was no difference between UAP and SAP. The occurrence of type II lesions in AMI and UAP patients was significantly higher than that in the SAP patients(95% vs 41%, PO.05; 83% vs 41%, PO.05), while no difference existed between the AMI and the UAP patients (P>0.05); (3) Levels of MPO in the femoral vein: The in-gate percentage of MPO in the UAP group was higher than that in the AMI, SAP and the control (85.33 + 5.69% vs 75.99 + 6.58%, 85.33 + 5.69% vs 80.07 + 8.18%, 85.33 + 5.69% vs 76.55+4.95%, P <0.05 respectively), while there were no significant differences among the latter 3 groups. The average fluorescent intensity of MPO was obviously weakened in the AMI group compared with those in the UAP, SAP and the contro 1(9.09 + 3.24 vs 18.19 + 8.81, 9.09 + 3.24 vs 16.98 + 7.26, 9.09 + 3.24 vs 17.81 ±6.19, P <0.05 respectively), while there were no significant difference among the latter 3 groups; (4) Concentration of hs-CRP in the femoral vein: Compared with the controls and SAP groups, concentrations of hs-CRP in the UAP and AMI groups were significantly increased (5.52+1.52mg/L vs 2.31+0.79mg/L, 6.36+1.41 mg/L vs 2.31+0.79 mg/L; 5.52 + 1.52mg/L vs 2.85 +1.22mg/L, 6.36+1.41mg/L vs 2.85+ 1.22mg/L, P <0.05), but no difference existed between the UAP and the AMI, neither between the SAP and the control; (5) Concentration of LDL in the femoral vein: Compared with the control, concentrations of LDL in the AMI, UAP and SAP groups were significantly increased (3.63±0.73mmo/L vs 2.62 + 0.57mmo/L, 3.79 + 0.94 mmo/L vs 2.62 + 0.57mmo/L, 3.55 + 0.49mmo/L vs 2.62 + 0.57mmo/L, PO.05 respectively), while the latter 3 groups did not differ from each other;(6) Association of the types of lesions with the level of MPO s hsCRP> LDL-c in the UAP group: Compared with the type I lesion, patients with type II lesions showed higher in-gate percentage ofMPO (85.13 + 7.61% vs 76.84 + 6.44%, PO.05), increased concentration of hs-CRP(5.83± 1.49 mg/L vs 2.78 + 0.97 mg/L, PO.05), and higher level of LDL-c (3.69 + 0.69 mmol/L vs 3.11+0.63 mmol/L, P<0.05); (7) Correlation between MPO and hsCRP, MPO and LDL-c: In the UAP group,the in-gate percentage of MPO correlated positively with the concentration of hs-CRP (r=0.88,P<0.001), and LDL-c (r =0.54, PO.005); In the AMI group, the average fluorescent intensity of MPO correlated negatively with the concentration of hs-CRP (r = -0.85, P<0.01), and showed no correlation with the level of LDL-c (r =0.21, P>0.05); (8) Comparison of the levels of MPO> hsCRP from different locations: In the UAP patients,the in-gate percentage of MPO, the average fluorescent intensity of MPO, and the concentrations of hs-CRP showed no difference between the samples from femoral vein and from the root of aortic artery. The percentage of MPO decreased in the coronary sinus compared with that in the root of aortic artery (80.95 + 5.42% vs87.83 + 5.96%, PO.01). The percentage of MPO decreased more through coronary circulation than through systemic circulation (-6.86 + 4.49 vs -0.98±3.87, PO.001); The average fluorescent intensity of MPO and the concentrations of hs-CRP showed no difference between samples from the coronary sinus and from the root of aortic artery. In the AMI patients , the in-gate percentage of MPO, the average intensity of MPO and the concentrations of hs-CRP showed no difference between samples from the femoral vein and from the root of aortic artery; The average fluorescent intensity of MPO in the coronary sinus was weakened compared with that in the root of aortic artery (6.73 + 2.55 vs 8.72+3.26, P<0.05). It decreased more through coronary circulation than through systemic circulation(-2.19±0.68 vs 0.19±0.66, PO.001). Neither the in-gate percentage of MPO nor the concentrations of hs-CRP showed significant difference between samples from the coronary sinus and from the root of aortic artery. In the control and SAP groups, none samples from the femoral vein, the root of aortic artery, or the coronary sinus showed different levels of MPO or hsCRP; (9) Demonstrations of electroscope: In the control and SAP groups, the neutrophil demonstrated regular shape, often in roundness, with different size , shape and density of particles, which...
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