Lipid profile in the evolution of experimental atherosclerotic plaques from thrombus

Nonocclusive white mural thrombosis was induced in the abdominal aortae of normolipidemic rabbits by insertion of a polyethylene catheter into the abdominal aortae. The thrombus subsequently organized into intimal thickenings which resembled fibrofatty type atherosclerosis seen in man, showing large numbers of foam cells containing stainable lipid, fatty necrotic centers, cholesterol clefts, calcification, and fibrous caps. The lipid composition of the thrombus and lesions was followed at serial time intervals from 4 hours to 60 weeks. Lipid analysis showed significant concentrations of lipid in the early lesions and with time these lipid concentrations increased and later decreased. These studies demonstrate that the fibrofatty lesions derived from a white thrombus have significant amounts of the same lipids that characterize the atherosclerotic lesions of man, however, there is a lower proportion of cholesterol to the other constituents and a higher proportion of phospholipids. The free cholesterol and cholesteryl ester of the 4-day lesions were much greater than that of platelets alone indicating that significant amounts of plasma are trapped in a thrombus when it forms.