Abstract 316: Hydroxytyrosol, An Olive Oil Phenol, Reduces Ex Vivo Thrombin-induced Platelet Activation

Abstract

Background and Aims: Olive oil consumption is associated with lower cardiovascular disease (CVD) risk. We recently demonstrated that frequent olive oil consumption was inversely associated with thrombin-induced platelet activation ex vivo . While various olive oil phenolic compounds, notably hydroxytyrosol, have been shown to reduce human platelet aggregation ex vivo , little is known about how olive oil affects platelet activation, a key mediator of atherothrombosis. Therefore, we sought to investigate whether hydroxytyrosol exposure affects platelet activation. Methods and Results: Ten healthy, non-smoking men and women (25.0±1.6 years) with normal body mass index (BMI 22.2±3.3 kg/m 2 ) were recruited for ex vivo platelet studies. Individuals on antiplatelet or anticoagulation medications or medications known to influence lipid levels were excluded. Subjects attended a single visit at NYU Langone where platelet-rich plasma (PRP) was isolated and incubated with three different concentrations of hydroxytyrosol or ethanol vehicle for 60 minutes at room temperature. PRP was then incubated with bovine thrombin for 5 minutes followed by anti-CD62P for 15 minutes in the dark. Platelet activation was determined by platelet surface expression of P-selectin, assessed via flow cytometry. E x vivo exposure to hydroxytyrosol inhibited thrombin-induced platelet P-selectin expression in a dose-dependent manner (Figure). Conclusions: We demonstrate that hydroxytyrosol exposure reduces thrombin-induced platelet P-selectin expression in a dose-response fashion. The dose response seen in this ex vivo platelet activation study is consistent with our clinical observation that more frequent olive oil intake was associated with reduced ex vivo thrombin-induced P-selectin expression. This laboratory study suggests a putative mechanism underlying our clinical observation as well as the established inverse association of olive oil consumption with CVD.