SUSCEPTIBILITY TO ATHEROSCLEROSIS IN MICE EXPRESSING EXCLUSIVELY APOLIPOPROTEIN B48 OR APOLIPOPROTEIN B100

All classes of lipoproteins considered to be atherogenic contain apo-B 100 or apo-B48, However. there is a distinct paucity of data regarding whether lipoproteins containing apo-B48 or apo-B100 differ in their i ntrinsic ability to promote the development of atherosclerosis, To add ress this issue, we compared the extent of atherosclerosis in three gr oups of animals: apo-E-deficient mice (apo-B(+/+)apo-E-/-) and apoE-de ficient mice that synthesize exclusively either apo-B48 (apo-B(48/48)a po-E-/-) or apo-B100 (apo-B(100/100)apo-E-/-). Mice (n = 25 in each gr oup) were fed a chow diet for 300 days, and plasma lipid levels were a ssessed throughout the study, Compared with the levels in apo-B(+/+)ap o-E-/- mice, the total plasma cholesterol levels were higher in the ap oB(100/100)apo-E-/- mice and were lower in the apo-B(48/48)apoE(-/-) m ice, However, the ranges of cholesterol levels in the three groups ove rlapped. Compared with those in the apo-B(+/+)po-E-/- mice, atheroscle rotic lesions were more extensive in the apo-B-48/48-E-/- mice and les s extensive in the apo-B(100/100)apo-E-/- mice, Once again, however, t here was overlap among the three groups, The extent of atherosclerosis in each group of mice correlated significantly with plasma cholestero l levels, In mice from different groups that had similar cholesterol l evels. the extent of atherosclerosis was quite similar, Thus, suscepti bility to atherosclerosis was dependent on total cholesterol levels, W hether mice synthesized apo-B48 or apo-B100 did not appear to have an independent effect on susceptibility to atherosclerosis.