Background Phospholipids on the surface of platelets play a key role in supporting coagulation in both health and disease. Alterations to phospholipid composition in platelets can contribute to thrombotic and bleeding disorders. We recently identified pro-coagulant enzymatically oxidized phospholipids (eoxPL) generated by platelets in response to thrombin activation via cyclooxygenase-1 (COX) and 12-lipoxygenase (LOX). It is not known how these lipids vary in relation to aspirin (a COX inhibitor) supplementation and/or gender.

Methods Twenty-eight healthy volunteers (14 males, 14 females) donated blood for platelet isolation at baseline (following a 14-day NSAID washout) and after 7-day supplementation with 75 mg aspirin. Repeat sampling took place 2 months and 4 months later to account for variations over time. Lipids were extracted from platelets either basally or following 30 min thrombin activation then analysed using liquid chromatography with tandem mass-spectrometry (LC-MS/MS) for the 49 most abundant eoxPL molecular species.

Results The majority (96%) of eoxPL increased in response to thrombin activation of platelets. Gender differences were observed with a trend towards higher levels generated by females. Correlation analysis highlighted clustering of eoxPL by enzymatic origin (12-LOX versus COX-1). Aspirin supplementation decreased eoxPL generated via COX-1 in both genders, but in males it increased levels of those generated by 12-LOX (p<0.05). Importantly, elevated levels of 12-hydroxyeicosatetraenoic acid (12-HETE)-containing eoxPL, which are known to be procoagulant, were observed. In contrast, generation of free 12-HETE was not affected by aspirin.

Conclusion In this study, we found an influence of both gender and aspirin supplementation on the generation of eoxPL in thrombin-activated platelets from healthy volunteers. Further characterisation of the gender influence may reveal novel mechanisms that contribute to the risk of arterial thrombosis in human populations.

Conflict of interest None declared