MIR21 and myocardial infarction: As a result, a total of 84 differentially expressed genes (DEGs) were identified (−0.5 < log2FC > 0.5, p < 0.05) (Additional file 1: Table S1), from which 48 protein-coding genes and 2 miRNA genes (MIR21 and MIR223) were upregulated, while 34 protein-coding genes were downregulated in MI patients.