Study Of Relativity Between Vulnerable Plaque With Serum Level Of Matrix Metallproteinase-9 In Patients With Acute Coronary Syndromes

Background: The pathology basis of acute coronary syndrome is the rupture or erosion of vulnerable plaque ,on which platelet accumulation and thrombus that can cause completed or non-completed block in coronary artery develop .The clinic manifestations of acute coronary syndrome include unstable angina pectoris, non ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction. Vulnerable plaques have a large lipid core and a thin fibrous cap .Fibrous cap is composed of collagen and matrix etc. Matrix metalloproteinases (MMPs) is a endogenous Zn²⁺-depended enzyme family .In this family, glutin-enzyme B (MMPs-9) specializing in degrading fundus membrane can degrades the extracellular matrix, accelerates the apoptosis of vascular smooth muscle cell, restrains the synthesis of collagen and thins fibrous cap tending to rupture. So MMPs-9 takes an important role in the rupture of AS plaque leading to acute coronary syndrome. There is important signification to identify vulnerable plaque early, forecast the risk of ACS in order to give early drug intervention to prevent the rupture of vulnerable plaque.Objective: Through observing the serum level of matrix metalloproteinase-9(MMPs-9) and high sensitive C-reactive protein(hs-CRP) in patients with acute coronary syndrome(ACS) and analyzing the relation between them ,The aim of this study is to discuss the diagnosis value of MMPs-9 to the plaques vulnerability of ACS, which will provide a fast and simple method for forecasting the plaques vulnerability of ACS clinically.Method: Fifty patients(31 men and 19 women, mean age is 55.8 ± 10.2 years)including 32 patients with unstable angina pectoris and 18 patients with acute myocardial infarct were studied. These patients were chosen according to thediagnosis criterion of ACC/AHA on acute coronary syndrome. Synchronously, 26 patients with stable angina pectoris and 30 healthy adults were chosen to be comparable groups. The sample was 2ml blood drawn out from the elbow vein of all patients be studied before breakfast on second day after admitted to hospital. After resting for 1 hour, the samples were centrifuged at 2500r/min for 10 minutes, then clean liquid was taken out and kept in refrigerator at temperature of -70°C until used. The serum MMPs-9 and hs-CRP level were measured by ELISA methods, compared the difference of serum MMPs-9 and hs-CRP level among groups and was compared and correlation between them was analyzed..Result: The serum MMP-9 and hs-CRP levels in ACS group were significantly higher than that in SA and control group(P<0.01).There was a significant difference in serum level of MMP-9 among ACS group, SAP group and control group, MMP-9 levels were correlated positively to hs-CRP.Conclusion: Vulnerability of plaque may be related to the increased serum level of MMP-9. Measuring serum MMP-9 may be a convenient and efficient method to predict the vulnerability of AS plaque.