Abnormal lipoprotein oxylipins in metabolic syndrome and partial correction by omega-3 fatty acids

Metabolic syndrome (MetSyn) is characterized by chronic inflammation which mediates the associated high risk for cardiovascular and other diseases. Oxylipins are a superclass of lipid mediators with potent bioactivities in inflammation, vascular biology, and more. While their role as locally produced agents is appreciated, most oxylipins in plasma are found in lipoproteins suggesting defective regulation of inflammation could be mediated by the elevated VLDL and low HDL levels characteristic of MetSyn. Our objective was to compare the oxylipin composition of VLDL, LDL, and HDL in 14 optimally healthy individuals and 31 MetSyn patients, and then to determine the effects of treating MetSyn subjects with 4 g/day of prescription omega-3 fatty acids (P-OM3) on lipoprotein oxylipin profiles. We compared oxylipin compositions of healthy (14) and MetSyn (31) subjects followed by randomization and assignment to 4 g/d P-OM3 for 16 weeks using LC/MS/MS. Compared to healthy subjects, MetSyn is characterized by abnormalities of (1) pro-inflammatory, arachidonate-derived oxylipins from the lipoxygenase pathway in HDL; and (2) oxylipins mostly not derived from arachidonate in VLDL. P-OM3 treatment corrected many components of these abnormalities, reducing the burden of inflammatory mediators within peripherally circulating lipoproteins that could interfere with, or enhance, local effectors of inflammatory stress. We conclude that MetSyn is associated with a disruption of lipoprotein oxylipin patterns consistent with greater inflammatory stress, and the partial correction of these dysoxylipinemias by treatment with omega-3 fatty acids could explain some of their beneficial effects.