Intracellular cholesterol accumulation is accompanied by enhanced proliferative activity of human aortic intimal cells.

Cholesterol accumulation in smooth muscle cells of unaffected human aortic intimal tissue occurred in the following conditions: (1) incubation of cells with atherogenic blood serum from patients with coronary heart disease (CHD), (2) cultivation of cells in the presence of insoluble associates containing low density lipoprotein (LDL). Preincubation of cells with blood serum from CHD patients resulted in a 2-5-fold increase in intracellular cholesterol and in 1.5-3-fold increase in cellular [3H]thymidine uptake. Blood serum collected from healthy donors had no significant effect on cultivated smooth muscle cells. When intimal cells were preincubated with insoluble associates containing LDL and components of fibrous extracellular matrix, the level of intracellular cholesterol increased from 2-4 times and uptake of [3H]thymidine increased 1.5-2.5-fold. Thus, a strong correlation was found between [3H]thymidine incorporation and intracellular cholesterol accumulation. The current study suggests that intracellular lipid accumulation may stimulate the proliferative activity of human aortic intimal cells from uninvolved tissue.