Differences in bovine aortic smooth muscle cells cultured from spontaneous atherosclerotic lesions of different severity within the same vessel.

Smooth muscle cells from normal segments, fatty streaks and fibrous plaques spontaneously arisen in the ascending part of the aorta of young normal bulls were grown in culture. Cells from fatty streaks proliferated more rapidly and grew to higher densities than the other cells, but collagen secretion did not differ from controls. In cells from fibrous plaques, however, proliferation rate and final density were the same as for controls, but collagen secretion was significantly increased, both at high and low cell density, compared to the other cells. These cell characteristics were evident in the first as well as in the fifth cell passage. The results support the view that the cell phenotype changes as the atherosclerotic lesions get more advanced, and these changes might be due to senescence and/or selection.