To Örebro University

BACKGROUND: Little is known about the effect of fish consumption on gene expression of inflammation-related genes in immune cells in coronary heart disease (CHD).

AIM OF THE STUDY: We sought to evaluate the effect of a fatty fish (FF) or a lean fish (LF) diet on the modulation of inflammatory and endothelial function-related genes in peripheral blood mononuclear cells (PBMCs) of subjects with CHD, and its association with serum fatty acid (FA) profile and lipid metabolic compounds.

METHODS: Data from 27 patients randomized into an 8-week FF (n = 10; mean +/- SD: 4.3 +/- 0.4 portions of fish per week), LF (n = 11; 4.7 +/- 1.1 portions of fish per week), or control diet (n = 6; 0.6 +/- 0.4 portions of fish per week) were analyzed. The mRNA expression was measured using real-time PCR.

RESULTS: The effect of the intervention on the mRNA expression of the genes studied did not differ among groups. In the FF group, however, the decrease in arachidonic acid to eicosapentaenoic acid (AA:EPA) ratio in cholesterol ester and phospholipid fractions strongly correlated with the change in IL1B mRNA levels (r (s) = 0.60, P = 0.06 and r (s) = 0.86, P = 0.002, respectively). In the LF group, the decrease in palmitic acid and total saturated FAs in cholesterol esters correlated with the change in intercellular cell adhesion molecule-1 (ICAM1) expression (r (s) = 0.64, P = 0.04 for both). Circulating levels of soluble ICAM-1 decreased only in the LF group (P < 0.05).

CONCLUSIONS: The intake of FF or LF diet did not alter the expression of inflammatory and endothelial function-related genes in PBMCs of patients with CHD. However, the decrease in AA:EPA ratio in serum lipids in the FF group may induce an anti-inflammatory response at mRNA levels in PBMCs. A LF diet might benefit endothelial function, possibly mediated by the changes in serum FA composition.