Association of apolipoprotein M with high-density lipoprotein kinetics in overweight-obese men

Area of Science:

• Lipid metabolism
• Cardiovascular research
• Endocrinology

Background:

• Obesity and insulin resistance are linked to dyslipidemia and cardiovascular disease.
• High-density lipoprotein (HDL) particles, particularly their apolipoproteins apoA-I and apoA-II, play a crucial role in reverse cholesterol transport.
• Apolipoprotein M (apoM) is an HDL-associated protein whose function in metabolic disease is not fully understood.

Purpose of the Study:

• To investigate the association between plasma apolipoprotein M (apoM) concentration and the kinetics of high-density lipoprotein apolipoprotein A-I (HDL apoA-I) and apolipoprotein A-II (HDL apoA-II) in overweight-obese, insulin-resistant men.

Main Methods:

• Plasma apoM concentration was measured using a highly specific sandwich ELISA.
• HDL apoA-I and apoA-II kinetics, including production and fractional catabolic rate (FCR), were determined using stable isotope labeling (D(3)-leucine) and multi-compartmental modeling.
• Participants included 60 overweight-obese men with insulin resistance.

Main Results:

• Plasma apoM concentration was inversely associated with body mass index and positively associated with total, LDL, and HDL cholesterol levels.
• Plasma apoM was positively correlated with apoA-I and apoA-II concentrations.
• Plasma apoM was negatively associated with the fractional catabolic rate (FCR) of both HDL apoA-I and HDL apoA-II, indicating slower catabolism.
• Multivariate analysis identified plasma apoM and triglycerides as independent predictors of HDL apoA-I and apoA-II FCR.

Conclusions:

• Plasma apoM may serve as a significant, independent predictor of HDL apoA-I and apoA-II catabolism.
• These findings suggest a role for apoM in modulating HDL metabolism, particularly in the context of obesity and insulin resistance.