Effects of fish oil supplementation on platelet survival and ex vivo platelet function in hypercholesterolemic patients

Little is known about the effects of dietary supplementation on platelet su rvival with low doses of n-3 and n-6 fatty acids in patients with hyperchol esterolemia, The effects of a 6-week intervention with fish oil capsules (d aily intake: 216 mg eicosapentaenoic acid, 140 mg docosahexaenoic acid, 390 mg gamma-linolenic acid, and 3480 mg linoleic acid) on in vivo platelet su rvival (In-111-oxine labeled platelets) and on ex vivo markers of platelet activation were investigated in a placebo-controlled, double-blind study wi th 26 hypercholesterolemic patients. In vivo platelet survival increased in the fish oil group (T) from a mean of 159 +/- 14 hours to a mean of 164 +/ - 12 hours (p=0.025), whereas it remained unchanged in the placebo (P) grou p (T vs. P; p=0.055). Ex vivo, thromboxane B-2 decreased from a mean of 225 +/- 16 to 212 +/- 21 ng/mL (p=0.003) in T but did not change in P (T vs. P : p=0.002). Malondialdehyde formation was lowered significantly by fish oil supplementation from a mean of 5.49 +/- 1.03 to 5.12 +/- 1.05 nM/10(9) pla telets, p=0.005, as compared with P (T vs. P; p=0.018). The trendwise decre ase in 11-DH-thromboxane B-2 plasma levels was not significant nor was the increase in platelet sensitivity to prostaglandn I-2 by fish oil. Baseline platelet survival in patients with hyperlipoproteinemia type IIa was not di fferent from those with hyperlipoproteinemia IIb and response to treatment in terms of platelet activation markers was not either. The changes in plat elet activation parameters in T were associated with significant reductions in cholesterol (-2.9%), low density lipoprotein cholesterol (-3.5%), and t riglycerides (-12.4%). Both ex vivo and in vivo platelet activation paramet ers exhibited signs of decreased activation by a 6-week diet supplemented w ith n-3 and n-6 fatty acids, which might be beneficial in reducing atheroth rombotic risk, in patients with hyperlipoproteinemia type IIa and IIb. (C) 1999 Elsevier Science Ltd. All rights reserved.