N-3 PUFAs reduce oxidative stress in ESRD patients on maintenance HD by inhibiting 5-lipoxygenase activity

Reactive oxygen species formation and release of proinflammatory/pro-atherogenic cytokines, that is, interleukin 1-β and tumor necrosis factor-α, need the activation of the arachidonic acid cascade via the enzyme 5-lipoxygenase (5-Lox). 5-Lox activity and expression are significantly increased in peripheral blood mononuclear cells (PBMCs) of end-stage renal disease (ESRD) patients on maintenance hemodialysis (HD). Diets enriched with n-3 polyunsaturated fatty acids (PUFAs) (ω-3) have been associated to a lower incidence of coronary heart disease (CHD) and a reduction in atherosclerotic lesions. Ω-3 may interfere with the arachidonic acid cascade by inhibiting 5-Lox. Lipid peroxidation, leukotriene B₄ (LTB₄) production, 5-Lox activity and expression were investigated in PBMC isolated from ESRD patients under maintenance HD before and after a 3-month oral supplementation with ω-3 at a daily dose of 2700 mg of n-3 PUFAs at the average eicosapentaenoic acid/docosaesaenoic acid ratio of 1.2 and finally after a further 3-month washout with no ω-3 supplementation. PBMCs from non-uremic volunteers were also investigated for comparison to normal parameters. Administration of ω-3 reduced significantly lipid peroxidation (P4 synthesis (P