The Effect of Low-Dose Marine n-3 Fatty Acids on Plasma Levels of sCD36 in Overweight Subjects: A Randomized, Double-Blind, Placebo-Controlled Trial

Abstract

CD36 is a scavenger receptor involved in lipid uptake and inflammation. Recently, non-cell-bound CD36 (sCD36) was identified in plasma and suggested to be a marker of lipid accumulation in the vessel wall. Marine n-3 polyunsaturated fatty acids (PUFA) may have cardioprotective effects. This study evaluated the effect of marine n-3 PUFA on sCD36 levels in overweight subjects. Fifty overweight subjects were randomized to 1.1 g of n-3 PUFA or 2 g of olive oil daily for six weeks. Neutrophils were isolated at baseline and after six weeks of treatment while an adipose tissue biopsy was obtained at baseline. The content of n-3 PUFA in adipose tissue and neutrophils was analyzed by gas chromatography, while plasma levels of sCD36 were determined using an enzyme-linked immunosorbent assay (ELISA). After six weeks of supplement plasma sCD36 did not differ between supplements (P = 0.18). There was no significant correlation between plasma sCD36 levels and n-3 PUFA in neutrophils at baseline (r = −0.02, P = 0.88), after six weeks supplement (r = −0.03, P = 0.85) or in adipose tissue (r = 0.14, P = 0.34). This study therefore does not provide evidence for a cardioprotective effect of n-3 PUFA acting through a CD36-dependent mechanism.

Effects of Omega-3 Fatty Acids on Immune Cells

“…Omega-3 fatty acids have been shown to be incorporated into phospholipids in the cell membrane of neutrophils at the expense of the omega-6 fatty acids linoleic and arachidonic acid [13,60]. Once the omega-3 fatty acids have been incorporated into the phospholipids, they can be metabolized by neutrophils into prostaglandins, leukotrienes, thromboxanes, maresins, protectins, and resolvins [10,61,62].…”

Fatty acids as modulators of neutrophil recruitment, function and survival

“…Most of the studies demonstrate that these fatty acids present important anti-inflammatory actions, which have been associated with different mechanisms including: alteration of cell membrane phospholipid fatty acid ͳͶ composition and consequentely change in the production of eicosanoids, disruption of lipid rafts and inhibition of transcription factors reducing the expression of proinflammatory genes(Calder, 2012; Martins de Lima et al, 2007).Incorporation of n-3 fatty acids in neutrophil membrane has been demonstrated by several groups in different conditions. In this context, low-dose of marine oil (1.1 g/day) ingestion, during 6 weeks, elevated the incorporation of n-3 fatty acids and reduced the percentage of arachidonic acid on neutrophil membranes(Veno et al, 2013).Sorensen et al (2014) demonstrated that ingestion of EPA (2.0 g/day) plus DHA (1.0 g/day) during 7 days increases by more than 3 fold the percentage of EPA and by 22% the incorporation of DHA in neutrophil membranes.…”