In C57BL6/J WT mice with myocardial infarction, PCSK9 promotes the polarization of M1-type macrophages and inhibits the polarization of M2-type macrophages by activating the TLR4/MyD88/NF-κB signaling pathway, leading to the significant inflammatory response, increased infarct size, and excessive impairment of cardiac function (43). Here, PCSK9 is linked to myocardial infarction.