Britannica Sources used in this answer

Why do low-density lipoproteins contribute to atherosclerosis?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

The role of coronary artery disease in heart attack — cardiovascular disease This micrograph shows a cross section of a coronary artery narrowed by an atherosclerotic plaque (purplish matter inside the artery). Most heart attacks are caused by the rupture of an atherosclerotic plaque, which triggers the formation of a clot that abruptly blocks blood flow to part of the heart muscle.

Low-density lipoproteins (LDLs) contribute to atherosclerosis by acting as the primary fatty material that infiltrates the innermost layer of the artery wall, known as the intima.12

As these protein-lipid complexes accumulate within the endothelial lining, they trigger an immune response. Macrophages—a type of white blood cell—are drawn to the site to scavenge the deposited lipids. Once these macrophages become engorged with lipids, they are referred to as "foam cells".21

These foam cells eventually die and accumulate at the site of the deposit, contributing to the formation and enlargement of atherosclerotic plaques, also called atheromas. The incorporation of these cholesterol-rich lipoproteins is a predominant factor in the progressive development of these plaques, which can narrow the vessel channel and interfere with blood flow, ultimately increasing the risk of serious cardiovascular events like heart attacks and strokes.123