Slowly Miscible Cholesterol Pools in Progressing and Regressing Atherosclerotic Aortas 1

Summary

Cholesterol pools were characterized metabolically in normal aorta and aortic plaques in White Carneau pigeons with naturally occurring, cholesterol-aggravated, and regressed atherosclerosis. Ultracentrifligation methods were used to separate in vivo [³H] cholesterol labeled aortic homogenates into top (nonbound), middle, and pellet (bound) fractions.

Naturally occurring and cholesterol-aggravated plaques had 40–50% of the total arterial cholesterol in the unbound pool whereas regressed lesions had only 8%. The unbound pool was described as the cholesterol capable of leaving a lesion after regression.

The bound fraction of all plaques was the site of a slowly miscible cholesterol pool, and an increased amount of elastin-bound cholesterol.

The relative miscibility of plaque cholesterol pools with plasma was the greatest in cholesterol-aggravated lesions, less in naturally occurring lesions and dramatically reduced in regressed lesions.

The authors acknowledge the excellent technical assistance of Mr. James Rodden and Ms. Nina Ann Stokes.