PCSK9 and atherosclerosis: To investigate the impact of immunosenescence on atherosclerosis development, we administered a single injection of a recombinant adeno-associated virus encoding for a gain-of-function for PCSK9 in combination with a Western-type diet for 10 weeks to young (3 months) and aged (18 months) C57Bl/6 mice (Fig. 1A).