EIIIA^–/–ApoE^–/– mice are protected from atherosclerosis. (A) Male and female ApoE^–/– (top) and EIIIA^–/–ApoE^–/– (bottom) aortae after 16 weeks on high-fat diet and stained with oil red O. (B) Quantification of total aortic lesion area over time on high-fat diet. (i) • indicates ApoE^–/– males (n = 10, n = 16, n = 7 at 8, 12, or 16 weeks, respectively); ▵, EIIIA^–/–ApoE^–/– males (n = 7, n = 13, n = 13 at 8, 12, or 16 weeks, respectively). (ii) • indicates ApoE^–/– females (n = 10, n = 9, n = 9at8, 12, or 16 weeks, respectively); ▵, EIIIA^–/–ApoE^–/– females (n = 9, n = 11, n = 17 at 8, 12, or 16 weeks, respectively). Total oil red O–positive area was determined by morphometry. *P < .002, **P < .001 versus ApoE^–/–, using the Mann-Whitney test of ranked data. Horizontal bars represent mean values for the group. (C) Distribution of lesions in regions of the aortic tree: arch, thoracic, and abdominal to iliac bifurcation. (i) ▪ indicates ApoE^–/– males; ▧, EIIIA^–/–ApoE^–/– males at 8, 12, or 16 weeks on high-fat diet. (ii) Females. Error bars represent SEM. (D) Cryosections of aortic arch lesions were stained with oil red O and hematoxylin. EIIIA^–/–ApoE^–/– lesions display patches of reduced lipid accumulation. L indicates vessel lumen; W, vessel wall.