Potential of pinolenic acid as a sustainable plant-sourced anti-inflammatory PUFA

Omega-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) modulate pro-inflammatory signalling pathways by altering the membrane lipid bilayer and assembly of signalling platforms. Fatty fish are the primary source of EPA and DHA; this source is not sustainable. Pinolenic acid (PLA) is an unusual fatty acid found in pine nuts and may be a sustainable land-sourced anti-inflammatory PUFA. Anti-inflammatory effects of PLA were compared to EPA and DHA in cultured EA.hy926 cells. Cells were treated with PUFAs (50 µM) for 48 hours before stimulation with tumour necrosis factor for 24 hours. All FAs were incorporated into EA.hy926 cells after 48 hours. Pre-treatment with PLA resulted in an increase in the elongation product, eicosatrienoic acid (ETA). Pre-treatment with PLA, EPA or DHA had differential effects depending on PUFA and cytokine examined. Pre-treatment of EA.hy926 cells with PLA resulted in a lower concentration of soluble ICAM-1; however, EPA and DHA showed greater reduction. MCP-1 production was lower after treatment with PLA, again to a lesser extent than EPA and DHA. Pre-treatment with DHA or PLA resulted in reduced adhesion of monocytes to EA.hy926 cells. This effect was not observed with EPA. PLA, DHA and EPA significantly decreased the ratio of pNF𝜅Bp65. Solid-state ²H NMR was used to examine the effects of PLA on model cell membrane dynamics. Increasing ratio of PLA to palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) was shown to lower the phase transition temperature of the POPC bilayer. 31P NMR spectra showed a decrease in peak width within increasing PLA ratios and a lower chemical shielding anisotropy, indicating more mobile lipid head groups and increased membrane disorder. PLA demonstrates anti-inflammatory effects with similar potency to EPA and DHA. Anti-inflammatory effects of PLA may be through altering pro-inflammatory signalling as a result of changes in cell membrane dynamics.