beta-VLDL hypercholesterolemia relative to LDL hypercholesterolemia is associated with higher levels of oxidized lipoproteins and a more rapid progression of coronary atherosclerosis in rabbits

The accumulation of the oxidized apolipoprotein, apoB-100, containing lipoproteins in the arterial wall and the progression of coronary atherosclerotic lesions in rabbits with beta-VLDL and LDL hypercholesterolemia was compared. In New Zealand White (NZW) rabbits on a 0.125% cholesterol diet, LDL cholesterol levels increased from 14 +/- 1 mg/dL (mean +/- SEM; n = 9) to 170 +/- 34 mg/dL (n = 10, P = .0002). On 0.5% cholesterol, LDL cholesterol levels were similar, but beta-VLDL cholesterol levels increased from 60 +/- 4 mg/dL (n = 10) to 550 +/- 75 mg/dL (n = 8; P < .0001). In Watanabe heritable hyperlipidemic (WHHL) rabbits, LDL cholesterol levels were 2.3-fold higher (n = 13; P < .0001) than in NZW rabbits on 0.5% cholesterol, whereas their beta-VLDL cholesterol levels were 3.7-fold lower (P < .0001), resulting in similar total cholesterol levels. At 2 months, mean intimal areas of lesions in the coronary arteries of NZW rabbits on 0.125% cholesterol were 0.13 +/- 0.045 mm2 (n = 4; mean +/- SEM) and were 5.8-fold, (n = 4; P = .016) and 2.0-fold (n = 6; P = NS versus 0.125% cholesterol and P = .014 versus 0.5% cholesterol) higher in NZW rabbits on 0.5% cholesterol and in WHHL rabbits, respectively. At 5 months, mean intimal areas were 0.47 +/- 0.088 mm2 (n = 6) in NZW rabbits on 0.125% cholesterol and were 4.5-fold (n = 4; P = .0001) and 2.0-fold (n = 7; P = .012 and P = .0019) higher in rabbits on 0.5% cholesterol and in WHHL rabbits, respectively. Levels of oxidized apoB-100 containing lipoproteins (both beta-VLDL and LDL) in the lesions correlated with mean intimal area (r = .88; n = 31; P < .0001) of those lesions and with the plasma levels of total beta-VLDL/LDL (r = .72; P < .0001). Levels of oxidized apoB-100 containing lipoproteins in the arterial wall correlate with progression of hypercholesterolemia-induced coronary atherosclerotic lesions. Plasma levels of beta-VLDL relative to similar increases in LDL result in a more pronounced accumulation of oxidized apoB-100 containing lipoproteins in the arterial wall and in the plasma and a more rapid progression of coronary atherosclerosis.