PCSK9 and atherosclerosis: Vascular aging, associated with increased IL-6 production by VSMCs, has been shown to promote atherogenesis in aged AAV-PCSK9–injected mice fed a WD for 10 weeks, exacerbating necrosis in atherosclerosis plaques of the aortic root.32 Additionally, inducing VSMC-specific senescence alone can increase atherosclerotic plaque size and necrotic area.63 In our model, which involved transplanting bone marrow from young or old donors into young recipient mice, we did not find differences in plaque size or necrosis between age groups.