Enhanced growth of smooth muscle cells from atherosclerotic rabbit aortas in culture

It has been suggested that cells in atherosclerotic lesions differ from normal arterial smooth muscle cells. The present study was aimed at elucidating this possibility. The morphology and growth characteristics of cells cultured from atherosclerotic rabbit aortas were compared with those obtained from control rabbits of the same age. Primary cultures were started from aortic intima-medial explants and they were subcultured after trypsinising the outgrowths. There were no differences in morphology between cells cultured from atherosclerotic and control animals as judged with phase contrast and electron microscopy. However, both the primary and subsequent growth rates of the cells cultured from atherosclerotic aortas were higher than those of control cells. Also the uptake of [3H]thymidine by cells derived from the atherosclerotic aortas was enhanced both in the exponential and stationary phases of cell growth. The results suggest that although the cells from atherosclerotic aortas are morphologically similar to normal arterial smooth muscle cells, atherogenesis is associated with the development of metabolic changes in the arterial cells that are carried over to daughter cells and persist even in culture.