Many studies focused on the crosstalk between the liver and heart [4,39,40] and found liver-derived cytokines, such as fibroblast growth factor 21, IL-22, proprotein convertase subtilisin/kexin type 9, and coagulation factor XI participated in cardiac protection after MI [41,42,43]. The gene discussed is PCSK9; the disease is myocardial infarction.