Plasma MicroRNA 499 as a Biomarker of

small RNAs 21–25 nucleotides in length. Recently, we reported that miRNA 208 (miR-208) is produced ex-clusively in the rat myocardium and that plasma miR-208 is a biomarker of myocardial injury in rats. In the present study, we assessed the hypothesis that plasma concentrations of myocardial-specific miRNAs can be used to diagnose myocardial injury in humans. METHODS: We used array analysis of miRNA produc-tion in various human tissues to identify heart-specific miRNAs. We assessed the plasma concentrations of miR-499 in 14 individuals with acute coronary syn-dromes, 15 individuals with congestive heart failure, and 10 individuals without cardiovascular diseases. Plasma miR-499 concentrations were measured with a real-time reverse-transcription PCR method that use