FGF21 and myocardial ischemia: After interacting with FGFR1 in cardiomyocytes in the presence of β-klotho, FGF21 activates its downstream kinases and proteins including phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB/AKT), and Bcl2 antagonist of cell death (BAD), thereby reducing myocardial ischemia-induced apoptosis characterized by reduction of caspase-3 activity [59].