Regulation of HDL dysfunctionality by phosphatidylethanolamine links poly-unsaturated fatty acids with...

Low plasma high-density lipoprotein (HDL)-cholesterol levels are associated with increased risk of atherosclerotic cardiovascular disease (ASCVD), potentially reflecting impaired antiatherogenic HDL functions. These latter are strongly influenced by the HDL phospholipidome, which is frequently altered in ASCVD patients. Several studies reported that plasma levels of phosphatidylethanolamine (PE) species, particularly PE (36:5), were positively associated with ASCVD, but the underlying mechanisms remain unclear. Plasma PE (36:5) exists as eicosapentaenoic (EPA)-PE and arachidonic acid (ARA)-PE, with the latter predominating in ASCVD. This study investigated whether the association of PE (36:5) with ASCVD might result from an impairment of the antiatherogenic functions of HDL.

Total PE and PE (36:5) content of large HDL isolated from 86 women with metabolic syndrome was positively associated with carotid intima-media thickness in multivariate regression analysis adjusted for traditional risk factors. In TgCETP x Ldlr^-/- mice fed a high-cholesterol diet, the atherosclerotic plaque size was greater when reconstituted HDL (rHDL) containing ARA-PE was injected retro-orbitally, compared with injection of control rHDL containing only phosphatidylcholine (PC). In vitro, PE rHDL showed reduced cholesterol efflux capacity and impaired anti-inflammatory activity in THP-1 macrophages, together with diminished anti-oxidative activity against LDL oxidation compared to control rHDL. Strikingly, ARA-PE rHDL profoundly weakened of the HDL functions, while EPA-PE counteracted the ARA-PE-induced dysfunction and potentiated the functionality of rHDL.

This study reveals a causal link between PE species, particularly ARA-PE, and HDL dysfunction, contributing to atherosclerosis. EPA-PE can restore HDL function, supporting the therapeutic potential of EPA reducing ASCVD risk.