Disrupted fatty acid distribution in HDL and LDL according to apolipoprotein E allele

Abstract

Objectives: Omega-3 polyunsaturated fatty acid (ω-3 PUFA) metabolism seems to be disrupted in carriers of the epsilon 4 allele of apolipoprotein E (E4+). The objective of this study was to investigate whether the ω-3 PUFA distribution in the high and low density lipoproteins is APOE-genotype dependant before and after supplementation with ω-3 PUFAs.

Methods: Eighty participants, aged between 20 and 35 y old were recruited and supplemented with 900 mg of eicosapentaenoic acid plus 680 mg of docosahexaenoic acid for 4 wk. Over the 4-wk intervention, blood samples were collected and HDL and LDL particles were obtained using sucrose gradient ultracentifugation. Fatty acid profiles of the HDL and LDL fractions were performed by gas chromatography.

Results: Baseline anthropometric characteristics of participants were not significantly different between the two APOE-groups (E4+, N = 10; E4-, N = 70). At baseline, in the LDL of E4+ subjects, the ω-6/ω-3 PUFA ratio was 17% higher than E4- subjects. At week 4, the ω-6/ω-3 PUFA ratio was significantly higher in the LDL of E4+ than E4- subjects. There was a significant genotype × time interaction for 16:0 in HDL and LDL and for 18:2 ω-6 in HDL. DHA in the HDL was positively correlated to HDL-C levels pre- and postsupplementation in E4- only.

Conclusions: Contrary to what we anticipated, ω-3 PUFAs content? in HDL and LDL were not APOE isoform-dependant in young participants. However, young E4+ participants already had a tendency toward lower baseline-DHA levels in LDL particles as well as a more atherogenic ω-6/ω-3 PUFA ratio in LDL pre- and post-supplementation.

Keywords: APOE isoforms; DHA; DHA metabolism; EPA; Omega-3 fatty acid; Omega-6/omega-3 fatty acid ratio; Plasma lipoproteins.