Impact of Epicatechin on the Procoagulant Activities of Microparticles

Microparticles play a role in cardiovascular disease pathology. The flavanol-like epicatechin is increasingly considered due to its cardioprotective effects. The aim of this study was to investigate the impact of epicatechin on microparticle generation, phenotype and procoagulant properties. Plasma samples from 15 healthy subjects were incubated with increasing concentrations of epicatechin (1 to 100 mu M). Then, the expression of glycoprotein IIb, phosphatidylserine (PS), glycoprotein Ib (GPIb) and P-selectin was assessed by flow cytometry analysis after (or not) platelet stimulation. Microparticle procoagulant activity was determined using Zymuphen MP and Zymuphen (TM) MP-TF for phospholipid and tissue factor content, and with thrombin generation (TG) assays for procoagulant function. Platelet microparticles that express GPIb (/mu L) decreased from 20,743 +/- 24,985 (vehicle) to 14,939 +/- 14,333 (p = 0.6), 21,366 +/- 16,949 (p = 0.9) and 15,425 +/- 9953 (p < 0.05) in samples incubated with 1, 10 and 100 mu M epicatechin, respectively. Microparticle concentration (nM PS) decreased from 5.6 +/- 2.0 (vehicle) to 5.1 +/- 2.2 (p = 0.5), 4.5 +/- 1.5 (p < 0.05) and 4.7 +/- 2.0 (p < 0.05) in samples incubated with 1, 10 and 100 mu M epicatechin, respectively. Epicatechin had no impact on tissue factor-positive microparticle concentration. Epicatechin decreased TG (endogenous thrombin potential, nM.min) from 586 +/- 302 to 509 +/- 226 (p = 0.3), 512 +/- 270 (p = 0.3) and 445 +/- 283 (p < 0.05). These findings indicate that epicatechin affects microparticle release, phenotype and procoagulant properties.