Uptake of exogenous and endogenous eicosapentaenoic acid by cultured human mononuclear cells

1. Peripheral blood mononuclear cells from eight healthy volunteers were cultured, with or without concanavalin A (Con A), in a medium containing (ml/l) 100 normal autologous serum, 100 experimental autologous serum or 100 heterologous (fetal calf) serum. 2. The control and experimental autologous sera were obtained from the volunteers, before and after 15 d supplementation with 15 g fish oil (MaxEPA)/d to provide 1.5 g eicosapentaenoic acid (EPA; 20:5n-3)/d. The sera were frozen at -20 degrees. The level of EPA increased from trace quantities in the control autologous serum to 14.3% w/w free fatty acids and between 6.9 and 8.1% w/w lipoprotein phospholipids in the experimental autologous serum. The heterologous fetal calf serum was enriched with EPA, complexed with bovine serum albumin, to provide a final concentration of 15 micrograms/ml. All culture medium contained 10 ml fresh autologous serum/l and cells were obtained from the volunteers for the culture studies about 60 d after the end of EPA supplementation. 3. Portions of cells were removed from culture at 36, 48 and 72 h for phospholipid fatty acid analysis. 4. The level of EPA in phospholipids of cells cultured with exogenous EPA in fetal calf serum was increased significantly (P less than 0.05) at all sampling times, both with and without Con A. By 48 h the levels had peaked at 15.8 (SE 2.7) and 18.4 (SE 4.5)% w/w respectively. 5. Resting cells, i.e. with no Con A present, failed to accumulate EPA when cultured in the experimental autologous serum containing 8.6% w/w total lipids as endogenous EPA.(ABSTRACT TRUNCATED AT 250 WORDS)