How does atherosclerosis develop in arteries?

Atherosclerosis is a progressive condition characterized by the deposition of fatty substances, such as cholesterol, within the innermost layer of the artery, known as the intima. While often associated with aging, it is a distinct disease process that can begin as early as childhood in the form of fatty streaks.1234

The development of atherosclerosis generally follows this sequence:

• Endothelial Injury: The process typically begins when the endothelium (the inner lining of the artery) sustains mechanical damage, often caused by factors such as high blood pressure, high levels of lipids, or tobacco smoke.2
• Accumulation and Inflammation: Following injury, platelets and monocytes accumulate at the site. Platelets release chemicals that attract more cells, while macrophages attempt to remove the lipid deposits.12
• Plaque Formation: Macrophages that become overwhelmed by lipid ingestion turn into "foam cells" and eventually die, contributing to the buildup of debris. This mixture of cells, fat, and connective tissue forms an atheroma, or fatty plaque.12
• Obstruction: As these plaques grow, they narrow the arterial lumen, restricting blood flow and potentially leading to heart attack or stroke if the plaque ruptures or causes a total blockage.523