KLB and cardiac hypertrophy: The activation of the mitogen-activated protein kinase signaling via the activation of FGFR1c/βKlotho for preventing cardiac hypertrophy [6], the Sirt1-PPARα pathway in the regulation of FGF21 expression in the heart [6], and the FGFR1/βKlotho–PI3K-Akt1-BAD signaling network in myocardial ischemia/reperfusion injury [35, 36] are pivotal pathways that protect cardiac cells from damage.