SMAD7 and Myocardial fibrosis: It has been suggested (26) that the three main target genes affecting myocardial fibrosis are SMAD family member 7 (Smad7) and sprouty1/2 (SPRY1/2), and miR-21 can promote myocardial fibrosis by controlling Smad7 and Spry1 (27, 28).