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DOI: 10.1055/s-0038-1629920
Impact of Multidrug Resistance Protein-4 Inhibitors on Modulating Platelet Function and High on-Aspirin Treatment Platelet Reactivity
Publikationsverlauf
07. August 2017
06. Dezember 2017
Publikationsdatum:
15. Februar 2018 (online)
Abstract
Platelet multidrug resistance protein 4 (MRP4) plays a modulating role on platelet activation. Platelet function and thrombus formation are impaired in MRP4 knockout mice models, and, among aspirin-treated patients, high on-aspirin residual platelet reactivity (HARPR) positively correlates with MRP4 levels. To better understand the effects of MRP4 on platelet function, the aim of this investigation was to assess the impact of cilostazol-induced inhibition of MRP4-mediated transport and assess aspirin-induced antiplatelet effects and rates of HARPR in human subjects.
Cilostazol-dependent inhibition of MRP4-mediated transport was assessed with the release of the fluorescent adduct bimane-glutathione and aspirin entrapment. Effect of Cilostazol on cAMP inhibition was evaluated by vasodilator-stimulated phosphoprotein (VASP). Platelet function was studied by collagen and TRAP-6-induced platelet aggregation and secretion.
Cilostazol reduced the release of bimane-glutathione and enhanced aspirin entrapment demonstrating an inhibitory effect on MRP4 in platelets. VASP phosphorylation was absent until 10 seconds after addition of cilostazol, and becomes evident after 30 seconds. An inhibitory effect on platelet aggregation and secretion was found in activated platelets, with threshold concentration of agonists, 10 seconds after addition of cilostazol, supporting a role of MRP4 on platelet function that is cAMP independent. Cilostazol effects were also shown in aspirin-treated platelets. A reduction of platelet aggregation and secretion were observed in aspirin-treated patients with HARPR.
This study supports the role of MRP4 on modulating platelet function which occurs through cAMP-independent mechanisms. Moreover, inhibition of MRP4 induced by cilostazol enhances aspirin-induced antiplatelet effects and reduces HARPR.
Key Points
1. Role of MRP4 on modulating platelet function through cAMP-independent mechanisms.
2. In patients on chronic aspirin therapy, inhibition of MRP4-mediated transport reduces high on-aspirin residual platelet reactivity.
Authors' Contribution
L. Alemanno designed the study, performed experiments, analysed results and wrote the manuscript. I. Massimi, V. Klaus, M.L. Guarino and T. Maltese, L. Frati and D.J. Angiolillo contributed to the study design, interpreted data and revised the intellectual content of the manuscript. F.M. Pulcinelli was responsible for the concept of the study, designed the study, analysed results and wrote the manuscript.
