PCSK9 and atherosclerosis: Young (3 months) and aged (18 months) male C57Bl/6 mice received a single i.v. injection of a recombinant adeno-associated virus encoding murine PCSK9 (rAAV8-D377Y-mPCSK9) and were fed a Western-type diet (WTD) for 10 weeks to induce atherosclerosis.