Protease‐activated receptor antagonists prevent thrombosis when dual antiplatelet therapy is insufficient in an occlusive thrombosis microfluidic model

Abstract

Background Platelet activation and arterial thrombosis on a ruptured atherosclerotic plaque is a major cause of myocardial infarction. Dual antiplatelet therapy (DAPT), the combination of platelet aggregation inhibitors, aspirin and a P2Y12 antagonist, is used to prevent arterial thrombosis. However, many people continue to have arterial thrombosis and myocardial infarction despite DAPT, indicating that additional therapies are required where DAPT is insufficient. Objectives To determine whether antagonists of protease‐activated receptors (PARs) can prevent occlusive thrombosis under conditions where DAPT is insufficient. Methods We used human whole blood in a microfluidic model of occlusive thrombosis to compare conditions under which DAPT is effective to those under which DAPT was not. Cangrelor (a P2Y12 antagonist) and aspirin were used to mimic DAPT. We then investigated whether the PAR1 antagonist vorapaxar or the PAR4 antagonist BMS 986120, alone or in combination with DAPT, prevented occlusive thrombosis. Results and Conclusions A ruptured plaque exposes collagen fibers and is often rich in tissue factor, triggering activation of platelets and coagulation. Occlusive thrombi formed on type I collagen in the presence or absence of tissue factor (TF). However, although DAPT prevented occlusive thrombosis in the absence of TF, DAPT had little effect when TF was also present. Under these conditions, PAR antagonism was also ineffective. However, occlusive thrombosis was prevented by combining DAPT with PAR antagonism. These data demonstrate that PAR antagonists may be a useful addition to DAPT in some patients and further demonstrate the utility of in vitro models of occlusive thrombosis.

PAR4 Antagonism in Patients With Coronary Artery Disease Receiving Antiplatelet Therapies

“…In ex vivo studies using a microfluidic model of occlusive thrombosis, PAR4 and PAR1 antagonism prevented thrombus formation in conditions where dual antiplatelet therapy was insufficient. 31 Our results add to these studies, suggesting a further antithrombotic benefit when PAR4 inhibition is combined with contemporary single or dual antiplatelet therapy and could indicate a novel antiplatelet strategy in patients at particularly high risk of atherothrombotic events.…”

Engineering Organ-on-a-Chip Systems for Vascular Diseases

“…17,53 EDTA quenching at the downstream of thrombotic site enabled accurate occlusion timing. 20,21 UV laser induced different wettability properties. 95 Ischemic Cross-connected parallel channels, 78,97,98 stenosis-integrated channel, 99 microwell plate format, 31 channel crosses microchamber 32 PDMS/glass, 78,97-99 PC, 31 PS 32 Cortical neurons, astrocytes, HUVECs, iECs, iCMs, collagen Microgrooves connecting parallel channels enabled neuronal segregation and axonal growth for modeling CNS axonal injury.…”

“…36 Coaxial 3D printing of 2-layered hydrogels was used for bioprinting of vein-and artery-like conduits. 34 Thrombosis Stenosis-integrated channel, 17,19,37,58,64,84,85 continues channel, 22,[86][87][88][89][90] H-shaped channel, 91 T-shaped channel, 92,93 Y-shaped channel, 20,42,94 branching channels 35,37,95 PDMS/glass, [19][20][21][22]58,64,86,87,91,96 PDMS, 17,84,88,92 glass, 85 GelMA, 42 collagen, 37 PDMS/ silica, 95 commercial devices, 89,90 agarose/gelatin 35 HUVECs, HDMVECs, HLMVECs, collagen, collagen/TF, VWF, fibroblasts, fibronectin…”

“…Polydimethylsiloxane (PDMS) is one of the most commonly used materials to fabricate microchannels in OOCs due to its several advantages including optical transparency, biocompatibility, moldability, and gas permeability. To improve the biocompatibility of PDMS channels and promote clot formation, various biointerfaces, including collagen, 16,17 fibronectin, 18,19 TFs (tissue factors), 20,21 VWF (von Willebrand factor), 22 and poly D-lysine, 23 have been applied to coat the channels. However, due to the nonspecific absorption of hydrophobic small molecules into PDMS, recent research is geared toward the application of alternative polymers including thermoplastics and polyesters.…”

“…The channels can be coated with collagen and TF patch to simulate plaque rupture and platelet activation, allowing for determination of time to occlude and investigation of antiplatelet drug effects. 20,21 As another example, collagen- or VWF-coated microchannels have been used to study vaccine-induced immune thrombotic thrombocytopenia, where blood containing anti-PF4 (anti-platelet factor 4) antibody could induce clot formation on the chip. 89,90 Modifying the microtopography and wettability of microchannels has also been shown to alter their thrombogenic properties.…”