The relationship between intimal necrosis and lipid accumulation during the onset and progression of atherosclerotic lesions.

In human coronary arteries, aorta and intracranial arteries, the first areas of intimal necrosis preceded the onset of the first lipid accumulation related to atherosclerotic involvement. Both intra- and extracellular lipid accumulations developed only in preexisting areas of intimal necrosis. Intimal necrosis not only caused an abnormal intraarterial retention of fat, but also caused fat to be deposited preferentially in specific forms and particular locations. The areas with mucoid necrosis appeared as adequate sites for the onset of fatty streaks; the areas with swelling necrosis appeared as adequate sites for a diffuse extracellular retention of tiny lipid droplets; the areas with dissecting necrosis appeared as adequate sites for large fatty deposits rich in cholesterol clefts. The results of this paper demonstrate that human atherosclerosis has many attributes of a necrotizing arteriopathy and that lipid accumulation is a secondary phenomenon. These results add support to the insudative theory of atherogenesis built up by German pathologists at the middle of this century and disagree with the often repeated view that human atherosclerosis is a reaction of the arterial wall to lipid that invade it.