EFFECTS OF TRANS N-3 POLYUNSATURATED FATTY-ACIDS ON HUMAN PLATELET-AGGREGATION

A recent study showed that human platelets may contain some EPA and DHA geometrical isomers, Previous data from our laboratory showed that these isomers can compete in vitro with arachidonic acid metabolism in platelets and alter aggregation. However, the effects of these isomers, when present in platelet lipids, has not yet been investigated. Human platelets were enriched with EPA, DHA or their respective Delta 17 or Delta 19 irans isomers in order to study the effects of these fatty acids on platelet aggregation and arachidonic acid metabolism. Platelets were stimulated by collagen or by the TxA(2)-stable analog, U46619. Both Irans isomers of EPA and DHA were less antiaggregant than their respective cis analogs when platelets were stimulated by collagen. However, the metabolism of arachidonic acid into HHT, 12 HETE and TxB(2) was apparently not modified. The response to U46619 was only slightly and not significantly modified by trans versus cis 20:5 and 22:6 fatty acids. It can be concluded that trans polyunsaturated fatty acids have different physiological effects than their respective cis homologues on platelet function, but the mechanisms by which they act needs further work to be totally elucidated.