Background: miRNAs are known to play a crucial role in cardiac development, and the expression of miRNA is altered in the diseased heart. The aim of this study was to investigate the value of plasma microRNA-499 (miR-499) as a novel biomarker for early diagnosis of acute myocardial infarction (AMI).
Methods: Enrolled in this study were 227 patients with chest pain on presentation to the departments of emergency and cardiology of Wuxi Second People's Hospital between October 2011 and May 2014. Additional 100 healthy individuals who received physical examination in the same hospital during the same period were used as control. Plasma was collected at admission, and the abundance of miR-499 was measured using reverse transcriptase-polymerase chain reaction (RT-PCR).
Results: MiR-499 was significantly elevated in 142 patients diagnosed with AMI as compared with 85 patients in non-AMI group and 100 subjects in healthy control group. Plasma miR-499 were already detectable in the plasma as early as 1 h after onset of chest pain in AMI patients, and continued to increase gradually without any sign of decreasing tendency within 9 h in AMI patients. miR-499 was highly positively correlated with the serum creatine kinase-MB (CK-MB) and cTnI. The area under the curve (AUC) of miR-499 for the diagnosis of AMI was 0.86, with an optimal cut-off value of 4.79, sensitivity of 80%, and specificity of 80.28%.
Conclusions: miR-499 was shown to substantially increase the diagnostic accuracy of CK-MB and cTnI in the diagnosis of AMI, and therefore it may prove to be a useful marker for early diagnosis of AMI.
Keywords: acute myocardial infarction (AMI); biomarker; early diagnosis; microRNA (miR).