APOA1 and atherosclerosis: Likewise, although mice that were deficient in the HDL receptor SR-BI (scavenger receptor class B type I) (SR-BI−/−) and received a Western-type diet for 20 weeks developed atherosclerosis [100,102], the double deficient Apoe−/− × SR-BI−/− mice, which expressed the endogenous apoA-I, developed severe atherosclerotic lesions as early as 4 to 5 weeks of age when fed a standard chow diet [98,99,100].