Low-density lipoprotein particle (LDL)

Low-density lipoprotein particles are spherical assemblies composed primarily of apolipoprotein B‑100, phospholipids, unesterified and esterified cholesterols, triglycerides, and ancillary proteins. They serve as major carriers transporting cholesterol through extracellular fluids in humans. Each native human low-density lipoprotein contains one molecule of apolipoprotein B‑100 embedded within its outer shell along with phospholipids and free cholesterol; its core contains cholesteryl esters and triglycerides. The physiological role is delivery of cholesterol—essential for membrane structure and steroid hormone synthesis—to peripheral tissues via interaction with cell-surface low-density lipoprotein receptors. Elevated concentrations are strongly associated with increased risk for development/progression of atherosclerotic cardiovascular disease due to deposition within arterial walls leading to plaque formation[1][2][3].

Other names

LDLLDL cholesterol (“bad cholesterol” in lay terms)Beta-lipoprotein (less common)

Mechanisms relate to lowering plasma concentrations of LDL particles:\n- Inhibition of HMG-CoA reductase reduces hepatic cholesterol synthesis and upregulates hepatic LDL receptors (statins).\n- Inhibition of intestinal absorption of cholesterol decreases delivery to the liver and increases clearance from blood (ezetimibe).\n- Inhibition of PCSK9 increases recycling and surface expression of hepatic LDL receptors for greater clearance from circulation.\n\nNone act by binding directly to the low-density lipoprotein particle itself.