Role of complement system in pathological remodeling of the vascular wall

•Complement proteins are abundantly present in both, atherosclerotic plaques and abdominal aortic aneurysm (AAA).•There are several triggers (immunolgobulins, proteases, cholesterol crystals) of complement activation in atherosclerotic plaques and AAA.•Complement activation is a main mediator linking lipid/protein deposition and inmune-inflamatory responses inside the vessel wall.•Genetic or pharmacological modulation of complement activation has shown protective effects atherosclerosis and AAA development.•Complement proteins are potential biomarkers of cardiovascular diseases.