High-density and low-density lipoproteins (HDL and LDL) (HDL and LDL)

High-density lipoproteins (HDL) and low-density lipoproteins (LDL) are complex macromolecular particles composed of lipids and specific proteins known as apolipoproteins, which facilitate the transport of water-insoluble lipids through the bloodstream (StatPearls, 2023: NBK507824). LDL is primarily responsible for delivering cholesterol to peripheral tissues, and its accumulation in the arterial wall is a central driver of atherosclerosis and coronary heart disease (NIH, 2022: High Blood Cholesterol). Conversely, HDL is involved in reverse cholesterol transport, a process that removes excess cholesterol from tissues and returns it to the liver for excretion, thereby exerting a cardioprotective effect (PubMed, 2018: PMID: 30139417). Therapeutic strategies targeting these particles focus on lowering LDL levels—primarily through HMG-CoA reductase inhibitors (statins), PCSK9 inhibitors, and cholesterol absorption inhibitors—or raising HDL levels via CETP inhibitors (Nature Reviews Cardiology, 2021: 10.1038/s41569-021-00553-2). Managing the balance between these lipoprotein fractions is a cornerstone of cardiovascular medicine, as dyslipidemia is a major modifiable risk factor for myocardial infarction and stroke (AHA, 2023: 10.1161/CIR.0000000000001123).

Other names

Apolipoprotein-containing particlesLipoprotein particlesGood and bad cholesterolHDL-CLDL-CVLDLIDL

Therapeutic intervention involves the inhibition of HMG-CoA reductase to reduce LDL synthesis, inhibition of PCSK9 to increase LDL receptor-mediated clearance, inhibition of CETP to modulate HDL/LDL exchange, and activation of PPAR-alpha to enhance triglyceride-rich lipoprotein clearance.