Transformation of Naturally Occurring Quiescent Intimal Smooth Muscle Cell Masses into Atherosclerotic Lesions in Swine Fed a Hyperlipidemic Diet
We have become increasingly aware that cholesterol diet-induced atherosclerosis in the abdominal aorta of young swine begins frequently (and perhaps exclusively) in pre-existing collections of intimal cells. The rather quiescent collections in the intima prior to feeding the atherogenic diet metamorphose into rapidly proliferating cell masses. It is too early to generalize that atherosclerosis will begin in this way in all arteries of all species including man; but it is a reasonable possibility. Pathologists have noted that atherosclerotic lesions often seem to arise in intimal smooth muscle cell (SMC) “cushions”, which begin to develop in fetal life near the orifices of branch vessels. They have also noted the presence of diffuse intimal thickening at points far removed from orifices, but have usually considered this a result of aging and probably not related to atherosclerosis. In recent studies of abdominal aortas of pre-adolescent swine, we found, in sites far removed from orifices, collections of intimal SMC indistinguishable from those near orifices. We also found continuous sheets of SMC similar to those observed in adult man (“diffuse intimal thickening”).
KeywordsAbdominal Aorta Tritiated Thymidine Cell Kinetic Atherogenic Diet Arterial Smooth Muscle Cell
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