Definition: Macrophages are cells of the immune system that exist in tissues and help defend the body against foreign cells like bacteria. They can release chemicals that stimulate other cells of the immune system, in addition to ingesting damaged and foreign cells.
Macrophages often migrate to inflamed areas of the body, including areas of inflammation on the vessels of the cardiovascular system. The presence of these macrophages, in addition to high cholesterol and triglycerides, can cause the formation of atherosclerosis.