The effect of low-dose marine n-3 fatty acids on the biosynthesis of pro-inflammatory 5-lipoxygenase pathway metabolites in overweight subjects: a randomized controlled trial

INTRODUCTION

Marine n-3 polyunsaturated fatty acids (PUFA) have a variety of anti-inflammatory properties. This study evaluated the effect of n-3 PUFA in a low, but recommended cardioprotective dosage on the formation of 5-lipoxygenase pathway metabolites in overweight subjects.

MATERIALS AND METHODS

Fifty subjects were randomized to 1.1g of n-3 PUFA or olive oil for 6 weeks.

RESULTS

Leukotriene B(4) formation decreased by 14% in the n-3 PUFA group which proved to be significant within the group (p=0.005) but not between groups (p=0.25). The formation of 5-hydroxyeicosatetraenoic acid (5-HETE) did not differ significantly between the groups. In the n-3 PUFA group, both 5-hydroxyeicosapentaenoic (5-HEPE) acid and leukotriene B(5) increased significantly compared to the control group (p<0.001).

CONCLUSION

In conclusion, we did not observe any significant net anti-inflammatory effect on the 5-lipoxygenase pathway from a daily supplement of 1.1g marine n-3 PUFA for 6 weeks.

Flow-mediated vasodilation and dietary intake of n-3 polyunsaturated acids in healthy subjects

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the two major marine n-3 polyunsaturated fatty acids (PUFA), have been proposed to decrease the risk of atherosclerosis and coronary heart disease. An early event during atherogenesis is endothelial dysfunction. We studied the correlation between fish consumption, serum phospholipid (sPL) levels of DHA and EPA and flow-mediated vasodilation (FMD), a measure of endothelial function. Furthermore, subjects were classified according to whether they did (Fish+, n = 19) or did not (Fish-, n = 21) follow the Danish recommendations, consuming at least 300 g fish/week. Neither the fish intake, sPL EPA nor sPL DHA significantly correlated with FMD, -0.20 (p = 0.23), -0.23 (p = 0.15) and -0.06 (p = 0.72), respectively. Also, when comparing the Fish+ and the Fish- group we did not find any significant differences in FMD (p = 0.33). In conclusion, our results did not show any correlation between intake and sPL levels of marine n-3 PUFA and FMD in healthy subjects.

Fatty acid composition of the internal mammary artery in relation to dietary intake of marine n-3 polyunsaturated fatty acids and association with flow-mediated vasodilation

Some evidence suggests that long-chain marine n-3 polyunsaturated fatty acids (n-3 PUFA) may increase production of vasodilatory nitric oxide from vascular endothelium. Fatty acids may therefore play a role for the left internal mammary artery (LIMA) graft function in coronary artery bypass grafting (CABG). However, little is known about the composition of fatty acids in the vessel wall of the LIMA. Using gas chromatography we investigated fatty acid composition in segments of the LIMA, in plasma nonesterified fatty acids (NEFA), in plasma phospholipid (PL) and in the pericardial adipose tissue (PAT) from 22 patients undergoing CABG. Furthermore, we investigated whether there was an association between the n-3 PUFA composition in LIMA and flow-mediated vasodilation (FMD). Self-reported fish consumption and supplementation of eicosapentaenoic acid and docosahexaenoic acids were reflected by the fatty acid composition in NEFA, PL and in PAT, but less so in the LIMA. There was no association between FMD and fatty acid composition of the LIMA.

Serum concentrations of matrix metalloproteinase-9, tissue inhibitor of matrix metalloproteinase-1 and alpha2-macroglobulin in healthy subjects after supplementation with different doses of marine n-3 fatty acids

OBJECTIVE

Extracellular matrix modification by matrix metalloproteinase-9 (MMP-9), tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) and alpha2-macroglobulin may affect the stability of atherosclerotic plaques. Marine n-3 polyunsaturated fatty acids (n-3 PUFA) may protect against plaque rupture. The aim was to investigate the effect of marine n-3 PUFA supplementation on serum levels of MMP-9, TIMP-1, and alpha2-macroglobulin.

METHODS

Healthy volunteers were randomized to receive capsules contributing either 6.6 g marine n-3 PUFA/day, 2.0 g marine n-3 PUFA/day or 6.6 g of olive oil (control). Serum MMP-9, TIMP-1 and alpha2-macroglobulin was measured at baseline and after 12 weeks of supplementation. One way ANOVA or Kruskal-Wallis test was used to compare groups.

RESULTS

60 healthy volunteers were enrolled and no subjects dropped out of the 12 week study. There were no statistically significant changes in serum levels of MMP-9, TIMP-1, and alpha2-macroglobulin in any of the three treatment groups (P=0.85, P=0.23 and P=0.87, respectively).

CONCLUSION

Supplementation with marine n-3 PUFA had no effect on serum levels of MMP-9, TIMP-1 and alpha2-macroglobulin in healthy subjects. The possible protection offered by marine n-3 PUFA against plaque rupture is therefore unlikely to be mediated through a change in serum levels of MMP-9, TIMP-1 and alpha2-macroglobulin.

The effect of N-3 fatty acids on plasma myeloperoxidase levels in healthy adults

OBJECTIVE

To examine the effect of marine n-3 polyunsaturated fatty acids (PUFA) supplementation in a low to moderate and a high dose on plasma levels of myeloperoxidase (MPO) in healthy individuals.

BACKGROUND

Atherosclerosis is a chronic inflammatory disease and MPO, which is secreted primarily from activated neutrophils and monocytes, has pro-inflammatory properties and has been linked with both initiation and propagation of atherosclerosis. Marine n-3 PUFA have anti-inflammatory properties, but whether n-3 PUFA affect plasma levels of MPO is largely unknown.

METHODS

Sixty healthy adults were randomized to three groups receiving either 6.6 g PUFA/day, 2.0 g PUFA/day or a control oil (olive oil) for 12 weeks. Blood samples were drawn at baseline and after exposure. Plasma levels of MPO were measured using a MPO ELISA-kit (from Mercodia, Uppsala, Sweden) with specific mouse monoclonal antibodies.

RESULTS

Plasma MPO concentrations (microg/L) at baseline were 36.9 +/- 9.4; 36.2 +/- 7.1 and 35.4 +/- 11.3 (for high dose-, low dose- and control-group, respectively). After 12 weeks of supplementation we found no significant changes in plasma MPO in any of the groups nor between groups, with values after intervention of 36.1 +/- 8.6; 37.0 +/- 8.2 and 34.4 +/- 11.1, respectively.

CONCLUSION

Supplementation with n-3 PUFA has no effect on plasma levels of MPO in healthy adults with low baseline levels of MPO.