Objective: We evaluated the potentiality of plasma microRNAs (miRNAs, or miRs) that were considered as novel biomarkers for acute coronary syndrome (ACS), including acute myocardial infarction (AMI) and unstable angina (UA).
Methods and results: We initially identified plasma miR-122, -140-3p, -144, -720, -1225-3p, -2861, and -3149 as candidate miRNAs associated with AMI (≥2 fold and P < 0.05) by comparing expression differences of miRNAs among AMI, non-coronary heart disease (non-CHD) and stable angina (SA) groups, using miRNA microarrays (n = 8 independent arrays in each group). Those seven plasma miRNAs were further examined with qRT-PCR analyses in two replications including 111 and 428 patients separately, and the results demonstrated that plasma miR-122, -140-3p, -720, -2861, and -3149 were elevated in the ACS group vs. the non-ACS (non-CHD + SA) group (P < 0.01). The area under the receiver operating characteristic curve (AUC) of the five miRNAs for ACS classification was 0.838, 0.818, 0.865, 0.852, and 0.670, respectively (all P < 0.001), while the values reached 0.843 and 0.925 when simultaneously with miR-122 and -3149 or with miR-122, -2861, and -3149 together (all P < 0.001). In plasma of pigs after coronary ligation, miR-122 was increased from 180 min to 240 min and miR-3149 was augmented from 30 min to 240 min compared with the sham pigs (all P < 0.05).
Conclusion: Plasma miR-122, -140-3p, -720, -2861, and -3149 were associated with and potentially novel biomarkers for ACS.