Aortic atherosclerotic lesion burden, represented by the percentage of lesion area to total aortic area, was quantified by en face analysis of aortas from mice of both sexes fed a HFD for 3 or 6 months. Representative en face preparations are shown (Lower panels). Lesion area was decreased in both male and female of TKO mutants fed a HFD for 3 or 6 months (A-3 month HFD and B-6 month HFD). Two-way ANOVA revealed a significant decrease in lesion area of Ip/mPges-1/ LdlR TKOs compared with LdlR KOs (3 month HFD- genotype, p< 0.0001, gender, p= 0.7010, interaction, p= 0.0304; 6 month HFD- genotype, p< 0.0001, gender, p= 0.0002, interaction, p= 0.4330). Data are expressed as means ± SEMs. *p< 0.05, **p< 0.01, ***p<0.001; n=17–21 per genotype.