Subfractions and subpopulations of HDL: an update

Area of Science:

• Cardiovascular Science
• Lipid Metabolism
• Biochemistry

Background:

• High-density lipoproteins (HDL) are recognized for their atheroprotective role, primarily through reverse cholesterol transport (RCT).
• HDLs possess diverse biological activities including antioxidant, anti-inflammatory, cytoprotective, vasodilatory, antithrombotic, and anti-infectious properties.
• Significant structural, metabolic, and biological heterogeneity exists among HDL particles, leading to various subclasses.

Purpose of the Study:

• To review recent findings on the atheroprotective and functional characteristics of different HDL subfractions.
• To provide an overview of methods used for separating HDL subfractions.
• To discuss the potential of HDL subclasses as biomarkers and therapeutic targets for cardiovascular risk.

Main Methods:

• Literature review of studies investigating HDL subclasses and their functions.
• Analysis of evidence regarding HDL modification and its impact on atherogenicity.
• Overview of current techniques for HDL subfraction separation.

Main Results:

• Different HDL subfractions and separation techniques yield varying associations with atheroprotection and cardiovascular risk.
• HDL particle modification, particularly in proteins and lipids, can impair protective functions and induce proatherogenic properties, especially in inflammatory states.
• HDL functionality appears to be a more promising therapeutic target than HDL cholesterol quantity, though optimal subfractions remain debated.

Conclusions:

• HDL subclasses are emerging as important biomarkers for predicting and reducing cardiovascular risk.
• Further research is needed to establish a 'gold standard' separation method and identify reliable HDL subfractions for risk assessment and therapeutic targeting.
• Focusing on HDL functionality and specific subfractions may lead to more effective cardiovascular therapies.