High-Density Lipoprotein, Lecithin: Cholesterol Acyltransferase, and Atherosclerosis

Area of Science:

• Cardiovascular Science
• Lipid Metabolism
• Atherosclerosis Research

Background:

• Epidemiological studies demonstrate a strong inverse correlation between plasma high-density lipoprotein cholesterol (HDL-C) and coronary heart disease incidence.
• High-density lipoproteins (HDL) possess atheroprotective properties, notably promoting cholesterol efflux from macrophages.
• HDL particles are heterogeneous and undergo continuous remodeling influenced by enzymes like lecithin:cholesterol acyltransferase (LCAT).

Purpose of the Study:

• To investigate the role of lecithin:cholesterol acyltransferase (LCAT) in high-density lipoprotein cholesterol (HDL-C) metabolism and its impact on atheroprotection.
• To reconcile contradictory findings regarding LCAT activity, HDL-C levels, and cardiovascular disease risk.

Main Methods:

• Review and analysis of existing epidemiological, animal, and human studies examining LCAT concentrations, activity, HDL-C levels, and atherosclerosis.
• Evaluation of the relationship between LCAT function and the atheroprotective capabilities of HDL particles.

Main Results:

• Increased LCAT concentrations are associated with elevated HDL-C levels but do not consistently confer atheroprotection.
• Decreased LCAT concentration and activity correlate with reduced HDL-C levels but not necessarily with increased atherosclerosis.
• These findings highlight a disconnect between HDL-C quantity and HDL functionality in the context of cardiovascular health.

Conclusions:

• Plasma HDL-C levels alone are insufficient indicators of the HDL system's functional capacity and atheroprotective potential.
• The role of LCAT in atheroprotection is complex and requires further elucidation beyond its effect on HDL-C levels.
• Future research should focus on assessing HDL functionality rather than solely relying on HDL-C concentrations for risk assessment.