| Background:Matrix metalloproteinases (MMP-9) is a kind of proteolytic enzyme which can hydrolyze gelatin, collagen, fibronectin and elastin. It has aother name—gelatinase B. MMP-9 can hydrolyze extracellular matrix (ECM) specifically and play an very important role in keeping integrity and stability of vessel. But in pathological state, much more MMP-9 can be secreted. Fibrous cap of plaque in coronary artery will be hydrolyzed by MMP-9 excessively and became more and more thinner. So MMP-9 result in the instability of plaque and increasing of risk of coronary heart disease (CHD). Optical coherence tomography (OCT) is a new technology which has developed rapidly in recent years. We can use OCT to calculate the content of lipid of plaque and the thickness of fibrous cap. Whats’more, OCT have very high distinguishability and can reflect the stability of plaque better than other methods. However, OCT also have some disadvantages, such as high risk and high cost. All of these result lead to that OCT can not be applied extensively in hospital. The relationship of MMP-9 and CHD is proved in more and more experiments recently. High level of MMP-9 can increase the risk of CHD.Objective:The levels of MMP-9 in patients from stable angina pectoris (SAP) group and acute coronary syndrome (ACS) group were determined by ELISA. OCT was used to measure the plaque fibrous cap thickness from SAP and ACS patients. Then we could analyze the difference of MMP-9 level in the the two groups and the relativity of MMP-9 level and thickness of fibrous cap. So we could explore the relationship between levels of MMP-9 and stability of plaque and the value of MMP-9 to predict the risk of CHD.Methods:Twenty-four men and eighteen women were choosen randomly from the patients who had receive the examine of coronary arteriography. There were twenty-two patients in SAP group and twenty patients in ACS groups. All the patients were conformed to WHO standards. Patients’ages, smoking history, weight and height were recorded correctly. Body mass index (BMI) was calculate for everyone. GLU, TG, TC, HDL-C, LDL-C were determined by automatic biochemical analyzer. Blood was centrifuged at the speed of 3000r/min for 10 minutes. The plasma was preserved under the environment of -80℃. ELISA was used to determine the level of MMP-9 at the same time. OCT was used to measure the plaque fibrous cap thickness. We analyzed the difference of levels of MMP-9, plaque fibrous cap thickness and in the two groups.We also analyzed the relativity between levels of MMP-9 and fibrous cap thickness and Gensini score. The relevance between all of the factors and fibrous cap thickness was analyzed by multiple stepwise regression analysis. All the data were analyzed by SPSS13.0.Results: ①There is no difference between general data from SAP and ACS group (P>0.05). ②The MMP-9 level of ACS group was higher than that of SAP group obviously (54.02±22.37μg/L vs 35.74±15.32μg/LP<0.01). ③Fibrous cap thickness of ACS group was thiner than that of SAP group (44.88±11.94μm vs 90.65±15.23μm P<0.01). ④ There is no difference between Gensini score of the two groups(58.42±20.25 vs 55.32±18.72 P>0.05). ⑤The level of MMP-9 was correlated inversely with plaque fibrous cap thickness in all patients(r=-0.611, P<0.01). ⑥ There is no relativity between level of MMP-9 and Gensini score in all patients(r=0.337, P>0.05).⑦Multiple stepwise regression analysis identified that MMP-9 predicted atherosclerotic plaque stability as an independent factor.Conclusion: ①There is a high level of MMP-9 in ACS patients.The level of MMP-9 was correlated inversely with plaque fibrous cap thickness. MMP-9 is an independent and effective marker which can predict atherosclerotic plaque stability and the risk of coronary heart disease.②Tere is no relativity between level of MMP-9 and Gensini score. Level of MMP-9 can predict atherosclerotic plaque stability but cannot predict the ponderance of atherosclerotic plaque. |
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