BACKGROUND: Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) has been implicated in vascular inflammation beyond its action on LDL-C degradation. We investigated whether PCSK9 may exacerbate proinflammatory signaling of M1 macrophages and if its neutralization with alirocumab could attenuate this effect and plaque progression by LDL-C independent mechanisms. METHODS: ApoE-/- mice were treated with alirocumab for 13 weeks, and aortic arches were isolated for atherosclerotic plaque characteri...