Effect of hyperlipemic serum on cholesterol accumulation in monkey aortic medial cells

The effect of hyperlipemic monkey serum on cholesterol ester formation and accumulation in monkey aortic medial cells grown in tissue culture was studied. The cellular incorporation and esterification of free cholesterol was followed using the specific activity of serum labeled with free [14C]cholesterol while the cellular sterol content was analyzed by gas-liquid chromatographic techniqyes. The effects produced by hyperlipemic monkey serum (HMS) and normal monkey serum (NMS) were evaluated at both comparable percentage levels in the media and at equivalent exogenous cholesterol concentrations. When the two sera were adjusted to equal exogenous free cholesterol levels, the incorporation of free cholesterol by the aortic medial cells was related to the free cholesterol concentration of the culture media whether supplied by normal or hyperlipemic serum cholesterol. Under these conditions the total cholesterol content of the HMS-grown cells was 35% greater than that of NMS-grown cells, due to an elevation in free cholesterol of approximately 3 mug/mg cell protein and a 2- to 4-fold increase in esterified cholesterol. At similar percentage levels, the hyperlipemic serum stimulated a greater incorporation of free cholesterol into the monkey medial cells, accompanied by a 2-fold increase in the cellular esterification of this free cholesterol.