New interpretations of lipoproteins and arterial lesions of cholesterol-fed rabbits.

The serum of cholesterol-fed rabbits contains lipoproteins rich in cholesterol, in contrast to those in thoracic duct lymph, which are rich in triglyceride. This study suggests that the serum lipoproteins may be "remnant" chylomicrons which have been stripped of their triglyceride, but which have not been removed from circulation by the liver, as usually occurs rapidly in other animal species. Electrophoresis of rabbit serum showed a broad beta band corresponding to the very low density lipoprotein fraction separated by ultracentritrifugation. This broad beta band may represent the "remnant particles". This proposed "remnant particle" hyperlipidaemia in rabbits may have its parallel in Type III human hyperlipidaemia, which also has a broad beta band on electrophoresis and may be a "remnant particle" disease. It was also found that early arterial lesions in rabbits are similar to some human fatty streaks, which if allowed to age for a further two years while the rabbits eat normal food, do not regress but mature to resemble calcified fibrous plaques.