Absence of monocyte chemoattractant protein-1 reduces atherosclerosis in low density lipoprotein receptor-deficient mice

Recruitment of blood monocytes into the arterial subendothelium is one of the earliest steps in atherogenesis. Monocyte chemoattractant protein-1 (MCP-1), a CC chemokine, is one likely signal involved in this process. To test MCP-l's role in atherogenesis, low density lipoprotein (LDL) receptor-deficient mice were made genetically deficient for MCP-1 and fed a high cholesterol diet. Despite having the same amount of total and fractionated serum cholesterol as LDL receptor-deficient mice with wild-type MCP-1 alleles, LDL receptor/MCP-1-deficient mice had 83% less lipid deposition throughout their aortas. Consistent with MCP-l's monocyte chemoattractant properties, compound-deficient mice also had fewer macrophages in their aortic walls. Thus, MCP-1 plays a unique and crucial role in the initiation of atherosclerosis and may provide a new therapeutic target in this disorder.