Lipoproteins, Cholesterol, and Cardiovascular Disease
Cholesterol and triglycerides are transported in the body by lipoproteins. The various classes of lipoprotein differ in the relative concentrations of their components: cholesterol, triglycerides, phospholipids, and proteins (apolipoproteins). Chylomicrons carry triglycerides following dietary lipid absorption, whereas very-low-density lipoproteins (VLDLs), which are produced by the liver, carry most circulating triglycerides. LDL, or “bad cholesterol,” is a product of the metabolism of VLDL and intermediate-density lipoprotein and is the primary carrier of cholesterol. High-density lipoprotein (HDL), or “good cholesterol,” is the smallest and densest lipoprotein particle. The result of the inflammatory interaction among these lipoproteins, macrophages, and the cellular components of the arterial wall is called atherosclerosis. Although patients’ cholesterol levels are what is typically measured, it is the lipoproteins that interact with the arterial wall, producing plaques. The narrowing of the arterial lumen that results from plaque growth or the rupture of a plaque with subsequent thrombosis leads to cardiovascular disease (CVD), including myocardial infarction (MI), stroke, and peripheral arterial disease.
Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.