TGFB1 and Myocardial fibrosis: As a key mediator of myocardial fibrosis, angiotensin II (Ang II) can up-regulate the expression of TGF-β1 by binding with angiotensin type 1 receptor (AT1R), which induces myocardial cell hypertrophy and enhances its secretion of profibrotic growth factor [12].