Involvement of ICAM-1 in the Progression of Atherosclerosis in APOE-knockout Mice

Recent clinical evidence has indicated that the level of soluble ICAM-1 (sICAM-1) is correlated with the severity of atherosclerosis and can predict future cardiovascular events. Here, using apolipoprotein E (APOE)-deficient mice, we investigated the level of sICAM-1 in parallel with endothelial ICAM-1 expression and aortic atherosclerosis. We also examined the effect of ICAM-1 deficiency during the progression of atherosclerosis using double knockout mice. The level of sICAM-1 increased significantly in parallel with the progression of atherosclerosis in APOE-deficient mice, while the sICAM-1 level remained constant in wild-type mice from 3 to 10 months of age. ICAM-1 staining was detected in virtually all endothelial cells, however, ICAM-1 was expressed strongly in the endothelium overlying atheromatous palque in APOE-deficient mice. Deficiency of ICAM-1 in APOE-deficient mice significantly reduced lesions after 5 and 10 months. The present study supported the notion that the level of sICAM-1 is closely related with the severity of atherosclerosis and cardiovascular events, and also suggested that inhibition of ICAM-1 can delay the progression of atherosclerosis.