In this pilot study, we investigated the effects on monocyte chemoattractant protein 1 (MCP-1; CCL2) secretion, MCP-1 gene expression and 15-deoxy Δ12,14-prostaglandin J2 (15d-PGJ2) production in peripheral blood mononuclear cells (PBMCs) of gamma-linolenic acid (GLA, 18:3 n−6) rich-borage oil supplemented healthy volunteers. GLA is rapidly converted to dihomo-gamma-linolenic acid (DGLA, 20:3 n−6) and in some cells desaturated further to arachidonic acid (AA, 20:4 n−6). In this study, we present data as seven healthy volunteers acting as their own controls who ingested 14 g borage oil per day consecutively for 13 weeks. It was found that the MCP-1 production from phytohaemagglutinin (PHA)-stimulated PBMCs was significantly reduced during the time course of the supplementation (Table). In addition, the level of PBMC MCP-1 gene expression was reduced significantly during the supplementation period (Table). A significant positive correlation was found between the expression of MCP-1 gene and MCP-1 production in stimulated cell cultures. There was a significant increase in stimulated 15d-PGJ2 production at weeks 7 and 13 (Table) and a significant negative correlation between 15d-PGJ2 production and MCP-1 production (Figure). In a parallel study using 14 g of corn oil [which contains linoleic acid (LA, 18:2 n−6) but no GLA] preliminary findings suggest no changes in MCP-1 (week 0, 1462±163 pg/ml v. week 13, 1045±73 pg/ml). The study suggests therefore that GLA-rich borage oil supplementation in humans results in the inhibition of PBMC MCP-1 expression at the gene and protein levels and that 15d-PGJ2, a metabolite of AA known to inhibit MCP-1, appears to be the mechanism by which GLA-rich borage oil inhibits MCP-1. The effects of GLA-rich borage oil on PBMC MCP-1 expression and production may be beneficial in certain chronic inflammatory diseases where MCP-1 has been strongly implicated.
Comparison between groups supplemented borage oil for weeks 4, 7 and 13, respectively and week 0 (without borage oil supplementation). *P<0.05, **P<0.01 and ***P<0.001.