BACKGROUND: Inflammation within vulnerable coronary plaques may cause unstable angina by promoting rupture and erosion. C-reactive protein (CRP) is the most reliable and accessible test method for clinical use for identifying coronary artery disease event. Matrix metalloproteinase 9 (MMP-9) is highly over-expressed in the vulnerable regions of a plaque. Our aim was to evaluate the plasma levels of MMP-9 and hsCRP in subjects with both unstable angina and coronary plaques, as well as in those with unstable angina without coronary plaques. METHODS: Patients with newly diagnosed unstable angina pectoris from clinical presentation and ECG, who were undergoing coronary angiography from April 2007 to April 2009, were included in this study. A total of 170 subjects were enrolled in the study. Before angiography, the baseline clinical data (mainly including conventional risk factors) was collected. These patients were divided into two groups, a non-plaque group (G1) which included 55 patients with no significant stenosis or less than 20% stenosis in at least one of the major coronary artery branches, and a plaque group (G2) which included 115 patients with at least one of the major coronary artery branches unstable angina pectoris with at least 50% stenosis of one major coronary artery. The patients presenting with calcified nodules of a major coronary artery were excluded from this study. We examined the serum levels of MMP-9 for all cases by multi-effect enzyme-linked immunosorbent assay. RESULTS: There was a significant difference in the serum levels of MMP-9 between the two groups (P < 0.001). The percentage of patients with hypertension, diabetes and current smokers were significantly different between the two groups (P = 0.034, P = 0.031, and P = 0.044 respectively). The univariate Logistic regression analyses of risk factors showed that smoking was the main risk factor for angina in the non-plaque group with the OR being 1.95 (95%CI 1.02 - 3.75). Hypertension, diabetes mellitus were negatively related with the occurrence of angina in the non-plaque group with the ORs being 0.50, and 0.36, respectively (95%CI 0.26 - 0.96 and 0.14 - 0.94). The MMP-9 level was negatively related to the occurrence of angina in the non-plaque group with an OR of 0.59 (95%CI 0.47 - 0.81). CONCLUSIONS: There is a significantly difference in MMP-9 levels between the plaque and non-plaque groups. Current smoking has a significant influence on unstable angina patients without documented plaques. The serum MMP-9 level may be a significant biomarker which can help differentiate patients with unstable angina with plaques from those with unstable angina but without plaques.
BACKGROUND: Inflammation within vulnerable coronary plaques may cause unstable angina by promoting rupture and erosion. C-reactive protein (CRP) is the most reliable and accessible test method for clinical use for identifying coronary artery disease event. Matrix metalloproteinase 9 (MMP-9) is highly over-expressed in the vulnerable regions of a plaque. Our aim was to evaluate the plasma levels of MMP-9 and hsCRP in subjects with both unstable angina and coronary plaques, as well as in those with unstable angina without coronary plaques. METHODS:Patients with newly diagnosed unstable angina pectoris from clinical presentation and ECG, who were undergoing coronary angiography from April 2007 to April 2009, were included in this study. A total of 170 subjects were enrolled in the study. Before angiography, the baseline clinical data (mainly including conventional risk factors) was collected. These patients were divided into two groups, a non-plaque group (G1) which included 55 patients with no significant stenosis or less than 20% stenosis in at least one of the major coronary artery branches, and a plaque group (G2) which included 115 patients with at least one of the major coronary artery branches unstable angina pectoris with at least 50% stenosis of one major coronary artery. The patients presenting with calcified nodules of a major coronary artery were excluded from this study. We examined the serum levels of MMP-9 for all cases by multi-effect enzyme-linked immunosorbent assay. RESULTS: There was a significant difference in the serum levels of MMP-9 between the two groups (P < 0.001). The percentage of patients with hypertension, diabetes and current smokers were significantly different between the two groups (P = 0.034, P = 0.031, and P = 0.044 respectively). The univariate Logistic regression analyses of risk factors showed that smoking was the main risk factor for angina in the non-plaque group with the OR being 1.95 (95%CI 1.02 - 3.75). Hypertension, diabetes mellitus were negatively related with the occurrence of angina in the non-plaque group with the ORs being 0.50, and 0.36, respectively (95%CI 0.26 - 0.96 and 0.14 - 0.94). The MMP-9 level was negatively related to the occurrence of angina in the non-plaque group with an OR of 0.59 (95%CI 0.47 - 0.81). CONCLUSIONS: There is a significantly difference in MMP-9 levels between the plaque and non-plaque groups. Current smoking has a significant influence on unstable anginapatients without documented plaques. The serum MMP-9 level may be a significant biomarker which can help differentiate patients with unstable angina with plaques from those with unstable angina but without plaques.