Since inflammatory cytokines are predominantly produced by monocytes and macrophages in cardiac tissue following MI3,5,7, and the highest increased level of miR-21 was showed in CD11b+ monocytes/macrophages as compared with that in cardiomyocytes or fibroblasts isolated from cardiac tissue of sham or MI group (Fig. S1B), we next explored the effects of miR-21 deficiency on inflammatory cytokine production in these two types of immune cells. This evidence concerns the gene ITGAM and myocardial infarction.