No abstract

Abstract-Macrophages/foam cells localized in cholesterol-and triglyceride-rich regions of atherosclerotic plaques express high levels of tissue factor (TF), the essential cofactor and receptor of factor VIIa. It is not clear whether modified lipoproteins, for which several agonistic effects on macrophages have been described, are independent stimuli of TF expression in these cells. Therefore, we studied the effect of short-term (1 day) and long-term (4 to 7 days) incubation of human monocyte-derived macrophages cultured in suspension with modified and native LDLs or VLDLs on the expression of TF mRNA, antigen, and activity. We used native LDL or VLDL, moderately oxidized LDL or VLDL, severely oxidized LDL or VLDL, acetylated LDL, and ␤-VLDL at a protein concentration of 100 g/mL. Cholesterol loading occurred within 9 hours after the addition of acetylated LDL and continued during long-term incubation. Incubation of severely oxidized LDL for 7 days resulted in a slight increase in cholesterol content.