Abstract 3492: The High Class A Macrophage Scavenger Receptor Gene Expression Level in the Peripheral Circulating Mononuclear Cells Is the Independent Predictive Marker for Reattack of Cardiovascular Event
Morbidity and mortality rates are still high among patients with acute coronary syndrome (ACS); moreover, it is clinically difficult to determine precisely which patients will progress satisfactorily. According to the results of gene chip microarray, we previously remarked that class A macrophage scavenger receptor (SR-A) in the peripheral circulating mononuclear cells (MNCs) was a candidate for being a predictive marker for acute coronary syndrome. In this study, we measured the SR-A gene expression levels in the MNCs in the patients with ACS or stable angina, and examined whether the high SR-A gene expression level in the chronic phase of ischemic heart disease is a prognostic marker for the cardiac events. We examined the SR-A gene expression levels of MNCs, by using real-time RT-PCR, in 73 patients: 32 patients with ACS in the acute phase; and, 41 patients with stable angina. The SR-A gene expression levels of the MNCs in the ACS and the stable angina groups were 13.9±10.1 and 4.7±2.7, respectively. The SR-A gene expression levels were significantly higher in the ACS group than in the stable angina group (p<0.0001). Out of these patients, 45 patients were followed up. We assigned the 45 patients into 2 groups, according to their SR-A gene expression levels in the stable phase, as follows: the low SR-A group (the SR-A gene expression level <6.0: median level) and the high SR-A group (the SR-A gene expression level ≥6.0). We examined the following 4 events: myocardial infarction; unstable angina; and, heart failure with NYHA class IV. The mean follow-up period was 1145 days (range 663 to 1497 days). Reattack of cardiac event occurred in 1 in the low SR-A group (4%), and in 10 patients in the high SR-A group (45%). Kaplan-Meier analysis revealed that the occurrence of a reattack of a cardiovascular event was significantly lower in the low SR-A group than in the high SR-A group (p=0.0004). Multiple logistic regression analysis revealed that the most predictive independent risk factor for a reattack of a cardiovascular event was a high SR-A gene expression level (p=0.009, relative risk=18.333). In conclusion, the SR-A gene expression level, even in the peripheral circulating blood, increases in the acute phase of ACS and provides a prognostic marker for a reattack of a cardiac event.