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Mavridis T, Choratta T, Papadopoulou A, Sawafta A, Archontakis-Barakakis P, Laou E, Sakellakis M, Chalkias A. Protease-Activated Receptors (PARs): Biology and Therapeutic Potential in Perioperative Stroke. Transl Stroke Res 2024:10.1007/s12975-024-01233-0. [PMID: 38326662 DOI: 10.1007/s12975-024-01233-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/12/2024] [Accepted: 02/01/2024] [Indexed: 02/09/2024]
Abstract
Perioperative stroke is a devastating complication that occurs during surgery or within 30 days following the surgical procedure. Its prevalence ranges from 0.08 to 10% although it is most likely an underestimation, as sedatives and narcotics can substantially mask symptomatology and clinical presentation. Understanding the underlying pathophysiology and identifying potential therapeutic targets are of paramount importance. Protease-activated receptors (PARs), a unique family of G-protein-coupled receptors, are widely expressed throughout the human body and play essential roles in various physiological and pathological processes. This review elucidates the biology and significance of PARs, outlining their diverse functions in health and disease, and their intricate involvement in cerebrovascular (patho)physiology and neuroprotection. PARs exhibit a dual role in cerebral ischemia, which underscores their potential as therapeutic targets to mitigate the devastating effects of stroke in surgical patients.
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Affiliation(s)
- Theodoros Mavridis
- Department of Neurology, Tallaght University Hospital (TUH)/The Adelaide and Meath Hospital, Dublin, incorporating the National Children's Hospital (AMNCH), Dublin, D24 NR0A, Ireland
- 1st Department of Neurology, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, 11528, Athens, Greece
| | - Theodora Choratta
- Department of General Surgery, Metaxa Hospital, 18537, Piraeus, Greece
| | - Androniki Papadopoulou
- Department of Anesthesiology, G. Gennimatas General Hospital, 54635, Thessaloniki, Greece
| | - Assaf Sawafta
- Department of Cardiology, University Hospital of Larisa, 41110, Larisa, Greece
| | | | - Eleni Laou
- Department of Anesthesiology, Agia Sophia Children's Hospital, 15773, Athens, Greece
| | - Minas Sakellakis
- Department of Medicine, Jacobi Medical Center-North Central Bronx Hospital, Bronx, NY, 10467, USA
| | - Athanasios Chalkias
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104-5158, USA.
- Outcomes Research Consortium, Cleveland, OH, 44195, USA.
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McFadyen JD, Mangin PH, Peter K. Of Mice and Man: The Unwinding of CLEC-2 as an Antithrombotic Target? Thromb Haemost 2022; 122:1963-1965. [PMID: 36070783 DOI: 10.1055/a-1938-1380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- James D McFadyen
- Atherothrombosis and Vascular Biology Program, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia.,Department of Haematology, Alfred Hospital, Melbourne, Victoria, Australia.,Department of Cardiometabolic Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Pierre H Mangin
- INSERM, EFS Grand-Est, BPPS UMR-S1255, FMTS, Université de Strasbourg, Strasbourg, France
| | - Karlheinz Peter
- Atherothrombosis and Vascular Biology Program, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia.,Department of Cardiometabolic Health, The University of Melbourne, Parkville, Victoria, Australia.,Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia
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Antagonism of Protease-Activated Receptor 4 Protects Against Traumatic Brain Injury by Suppressing Neuroinflammation via Inhibition of Tab2/NF-κB Signaling. Neurosci Bull 2020; 37:242-254. [PMID: 33111257 DOI: 10.1007/s12264-020-00601-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 07/19/2020] [Indexed: 12/23/2022] Open
Abstract
Traumatic brain injury (TBI) triggers the activation of the endogenous coagulation mechanism, and a large amount of thrombin is released to curb uncontrollable bleeding through thrombin receptors, also known as protease-activated receptors (PARs). However, thrombin is one of the most critical factors in secondary brain injury. Thus, the PARs may be effective targets against hemorrhagic brain injury. Since the PAR1 antagonist has an increased bleeding risk in clinical practice, PAR4 blockade has been suggested as a more promising treatment. Here, we explored the expression pattern of PAR4 in the brain of mice after TBI, and explored the effect and possible mechanism of BMS-986120 (BMS), a novel selective and reversible PAR4 antagonist on secondary brain injury. Treatment with BMS protected against TBI in mice. mRNA-seq analysis, Western blot, and qRT-PCR verification in vitro showed that BMS significantly inhibited thrombin-induced inflammation in astrocytes, and suggested that the Tab2/ERK/NF-κB signaling pathway plays a key role in this process. Our findings provide reliable evidence that blocking PAR4 is a safe and effective intervention for TBI, and suggest that BMS has a potential clinical application in the management of TBI.
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Gerzanich V, Kwon MS, Woo SK, Ivanov A, Simard JM. SUR1-TRPM4 channel activation and phasic secretion of MMP-9 induced by tPA in brain endothelial cells. PLoS One 2018; 13:e0195526. [PMID: 29617457 PMCID: PMC5884564 DOI: 10.1371/journal.pone.0195526] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 03/23/2018] [Indexed: 11/25/2022] Open
Abstract
Background Hemorrhagic transformation is a major complication of ischemic stroke, is linked to matrix metalloproteinase-9 (MMP-9), and is exacerbated by tissue plasminogen activator (tPA). Cerebral ischemia/reperfusion is characterized by SUR1-TRPM4 (sulfonylurea receptor 1—transient receptor potential melastatin 4) channel upregulation in microvascular endothelium. In humans and rodents with cerebral ischemia/reperfusion (I/R), the SUR1 antagonist, glibenclamide, reduces hemorrhagic transformation and plasma MMP-9, but the mechanism is unknown. We hypothesized that tPA induces protease activated receptor 1 (PAR1)-mediated, Ca2+-dependent phasic secretion of MMP-9 from activated brain endothelium, and that SUR1-TRPM4 is required for this process. Methods Cerebral I/R, of 2 and 4 hours duration, respectively, was obtained using conventional middle cerebral artery occlusion. Immunolabeling was used to quantify p65 nuclear translocation. Murine and human brain endothelial cells (BEC) were studied in vitro, without and with NF-κB activation, using immunoblot, zymography and ELISA, patch clamp electrophysiology, and calcium imaging. Genetic and pharmacological manipulations were used to identify signaling pathways. Results Cerebral I/R caused prominent nuclear translocation of p65 in microvascular endothelium. NF-κB-activation of BEC caused de novo expression of SUR1-TRPM4 channels. In NF-κB-activated BEC: (i) tPA caused opening of SUR1-TRPM4 channels in a plasmin-, PAR1-, TRPC3- and Ca2+-dependent manner; (ii) tPA caused PAR1-dependent secretion of MMP-9; (iii) tonic secretion of MMP-9 by activated BEC was not influenced by SUR1 inhibition; (iv) phasic secretion of MMP-9 induced by tPA or the PAR1-agonist, TFLLR, required functional SUR1-TRPM4 channels, with inhibition of SUR1 decreasing tPA-induced MMP-9 secretion. Conclusions tPA induces PAR1-mediated, SUR1-TRPM4-dependent, phasic secretion of MMP-9 from activated brain endothelium.
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Affiliation(s)
- Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Min Seong Kwon
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Seung Kyoon Woo
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alexander Ivanov
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - J. Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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PAR-4 - The PARagon of protease-activated receptors? Int J Cardiol 2018; 252:167-168. [PMID: 29249426 DOI: 10.1016/j.ijcard.2017.11.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 11/07/2017] [Indexed: 11/24/2022]
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van den Eshof BL, Hoogendijk AJ, Simpson PJ, van Alphen FPJ, Zanivan S, Mertens K, Meijer AB, van den Biggelaar M. Paradigm of Biased PAR1 (Protease-Activated Receptor-1) Activation and Inhibition in Endothelial Cells Dissected by Phosphoproteomics. Arterioscler Thromb Vasc Biol 2017; 37:1891-1902. [PMID: 28818855 DOI: 10.1161/atvbaha.117.309926] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/03/2017] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Thrombin is the key serine protease of the coagulation cascade and mediates cellular responses by activation of PARs (protease-activated receptors). The predominant thrombin receptor is PAR1, and in endothelial cells (ECs), thrombin dynamically regulates a plethora of phosphorylation events. However, it has remained unclear whether thrombin signaling is exclusively mediated through PAR1. Furthermore, mechanistic insight into activation and inhibition of PAR1-mediated EC signaling is lacking. In addition, signaling networks of biased PAR1 activation after differential cleavage of the PAR1 N terminus have remained an unresolved issue. APPROACH AND RESULTS Here, we used a quantitative phosphoproteomics approach to show that classical and peptide activation of PAR1 induce highly similar signaling, that low thrombin concentrations initiate only limited phosphoregulation, and that the PAR1 inhibitors vorapaxar and parmodulin-2 demonstrate distinct antagonistic properties. Subsequent analysis of the thrombin-regulated phosphosites in the presence of PAR1 inhibitors revealed that biased activation of PAR1 is not solely linked to a specific G-protein downstream of PAR1. In addition, we showed that only the canonical thrombin PAR1 tethered ligand induces extensive early phosphoregulation in ECs. CONCLUSIONS Our study provides detailed insight in the signaling mechanisms downstream of PAR1. Our data demonstrate that thrombin-induced EC phosphoregulation is mediated exclusively through PAR1, that thrombin and thrombin-tethered ligand peptide induce similar phosphoregulation, and that only canonical PAR1 cleavage by thrombin generates a tethered ligand that potently induces early signaling. Furthermore, platelet PAR1 inhibitors directly affect EC signaling, indicating that it will be a challenge to design a PAR1 antagonist that will target only those pathways responsible for tissue pathology.
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Affiliation(s)
- Bart L van den Eshof
- From the Department Plasma Proteins (B.L.v.d.E., A.J.H., P.J.S., K.M., A.B.M., M.v.d.B.), Department of Research Facilities (F.P.J.v.A., A.B.M.), Sanquin Research, Amsterdam, The Netherlands; Tumour Microenvironment and Proteomics Laboratory, Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.); Tumour Microenvironment and Proteomics Laboratory, Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.); Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands (K.M., A.B.M.)
| | - Arie J Hoogendijk
- From the Department Plasma Proteins (B.L.v.d.E., A.J.H., P.J.S., K.M., A.B.M., M.v.d.B.), Department of Research Facilities (F.P.J.v.A., A.B.M.), Sanquin Research, Amsterdam, The Netherlands; Tumour Microenvironment and Proteomics Laboratory, Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.); Tumour Microenvironment and Proteomics Laboratory, Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.); Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands (K.M., A.B.M.)
| | - Pelle J Simpson
- From the Department Plasma Proteins (B.L.v.d.E., A.J.H., P.J.S., K.M., A.B.M., M.v.d.B.), Department of Research Facilities (F.P.J.v.A., A.B.M.), Sanquin Research, Amsterdam, The Netherlands; Tumour Microenvironment and Proteomics Laboratory, Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.); Tumour Microenvironment and Proteomics Laboratory, Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.); Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands (K.M., A.B.M.)
| | - Floris P J van Alphen
- From the Department Plasma Proteins (B.L.v.d.E., A.J.H., P.J.S., K.M., A.B.M., M.v.d.B.), Department of Research Facilities (F.P.J.v.A., A.B.M.), Sanquin Research, Amsterdam, The Netherlands; Tumour Microenvironment and Proteomics Laboratory, Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.); Tumour Microenvironment and Proteomics Laboratory, Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.); Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands (K.M., A.B.M.)
| | - Sara Zanivan
- From the Department Plasma Proteins (B.L.v.d.E., A.J.H., P.J.S., K.M., A.B.M., M.v.d.B.), Department of Research Facilities (F.P.J.v.A., A.B.M.), Sanquin Research, Amsterdam, The Netherlands; Tumour Microenvironment and Proteomics Laboratory, Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.); Tumour Microenvironment and Proteomics Laboratory, Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.); Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands (K.M., A.B.M.)
| | - Koen Mertens
- From the Department Plasma Proteins (B.L.v.d.E., A.J.H., P.J.S., K.M., A.B.M., M.v.d.B.), Department of Research Facilities (F.P.J.v.A., A.B.M.), Sanquin Research, Amsterdam, The Netherlands; Tumour Microenvironment and Proteomics Laboratory, Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.); Tumour Microenvironment and Proteomics Laboratory, Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.); Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands (K.M., A.B.M.)
| | - Alexander B Meijer
- From the Department Plasma Proteins (B.L.v.d.E., A.J.H., P.J.S., K.M., A.B.M., M.v.d.B.), Department of Research Facilities (F.P.J.v.A., A.B.M.), Sanquin Research, Amsterdam, The Netherlands; Tumour Microenvironment and Proteomics Laboratory, Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.); Tumour Microenvironment and Proteomics Laboratory, Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.); Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands (K.M., A.B.M.)
| | - Maartje van den Biggelaar
- From the Department Plasma Proteins (B.L.v.d.E., A.J.H., P.J.S., K.M., A.B.M., M.v.d.B.), Department of Research Facilities (F.P.J.v.A., A.B.M.), Sanquin Research, Amsterdam, The Netherlands; Tumour Microenvironment and Proteomics Laboratory, Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.); Tumour Microenvironment and Proteomics Laboratory, Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.); Department Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, The Netherlands (K.M., A.B.M.).
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Witkowski M, Landmesser U, Rauch U. Tissue factor as a link between inflammation and coagulation. Trends Cardiovasc Med 2016; 26:297-303. [DOI: 10.1016/j.tcm.2015.12.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 12/08/2015] [Accepted: 12/08/2015] [Indexed: 10/22/2022]
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Serebruany VL, Kim MH, Hanley DF. Vorapaxar monotherapy for secondary stroke prevention: A call for randomized trial. Int J Stroke 2016; 11:614-7. [PMID: 26860124 DOI: 10.1177/1747493016632253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/10/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Vorapaxar, a novel platelet thrombin protease-activated receptor 1 blocker, is currently approved for post-myocardial infarction and peripheral artery disease indications on top of clopidogrel or/and aspirin. We sought to summarize the conflicting stroke data after vorapaxar for justifying a secondary stroke prevention trial. METHODS Analyses of the stroke data after vorapaxar yielded from thrombin-receptor antagonist vorapaxar in acute coronary syndromes (TRACER) and TRA2P clinical trials, and affiliated Food and Drug Administration (FDA) reviews. RESULTS The stroke data are mixed, with catastrophic 2.5 excess of intracranial bleeding risks (HR = 2.52; 95% CI = 1.46-4.36, p < 0.0001); trend to worsened second stroke rates (13.0% vs. 11.7%; HR = 1.03; 95% CI = 0.85-1.25, p = NS), but a hint towards less primary ischemic strokes in vorapaxar indicated population (HR = 0.57; 95% CI = 0.43 to 0.75; p < 0.001). These conflicting data are not solely attributed to vorapaxar, but rather reflect unreasonably aggressive triple antiplatelet strategies utilized frequently in TRA2P and dominant in TRACER. Overall, the FDA-confirmed evidence advocates future vorapaxar secondary stroke prevention trial due to being first-in-class agent, unique pharmakynetics, and exhibiting very mild "comfort zone" antiplatelet profile. The three arm trial testing head-to-head monotherapy with vorapaxar (Zontivity®), versus clopidogrel (Plavix®), and versus extended-released dipyridamole with very low dose aspirin (Aggrenox®) is warranted. CONCLUSIONS Vorapaxar may be superior to currently recommended antiplatelet strategies and should be tested as a monotherapy in a randomized outcome-driven secondary stroke prevention trial.
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Affiliation(s)
- Victor L Serebruany
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland, MD, USA
| | - Moo H Kim
- Clinical Trial Center, Dong-A University Hospital, Busan, Republic of Korea
| | - Daniel F Hanley
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland, MD, USA
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Serebruany VL, Kim MH, Fortmann SD, Hanley DF. Vorapaxar for secondary stroke prevention: perspectives and obstacles. Expert Rev Neurother 2015; 15:1377-82. [PMID: 26566105 DOI: 10.1586/14737175.2015.1111761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Vorapaxar, a novel antiplatelet thrombin protease-activated receptor 1 (PAR-1) inhibitor, has been evaluated in the successful TRA2P trial and failed TRACER trial. The drug is currently approved for post myocardial infarction and peripheral artery disease indications on top of clopidogrel and/or aspirin. The stroke data after vorapaxar are mixed, dominated with heavy excess of intracranial bleeding risks and slightly worsened second stroke rates, but show less primary ischemic strokes. Fortunately, these conflicting data do not belong purely to vorapaxar per se but rather, reflect unreasonably aggressive strategies, including predominantly triple antiplatelet therapy, utilized in both Trial to Assess the Effects of SCH 530348 in Preventing Heart Attack and Stroke in Patients with Arteriosclerosis (TRA2P) and especially in Thrombin-Receptor Antagonist Vorapaxar in Acute Coronary Syndromes (TRACER). The FDA-confirmed evidence strongly suggests that unique pharmacokinetics and a very mild "comfort zone" antiplatelet profile makes vorapaxar a good candidate for improved secondary stroke prevention. The outcome-driven, randomized trial should test head-to-head monotherapy with vorapaxar (Zontivity®) versus clopidogrel (Plavix®) and versus dipyridamole with very low dose aspirin (Aggrenox®). The advantages and potential pitfalls of such a trial are discussed in this article.
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Affiliation(s)
| | | | | | - Dan F Hanley
- a Department of Neurology, Johns Hopkins University, Baltimore , MD , USA
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Risk and benefit of direct oral anticoagulants or PAR-1 antagonists in addition to antiplatelet therapy in patients with acute coronary syndrome. Thromb Res 2015; 136:243-9. [PMID: 26037286 DOI: 10.1016/j.thromres.2015.05.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/05/2015] [Accepted: 05/22/2015] [Indexed: 01/19/2023]
Abstract
BACKGROUND The overall risk-benefit profile of direct oral anticoagulants (DOACs) or PAR-1 antagonists in addition to antiplatelet therapy for patients with acute coronary syndrome (ACS) has not been clearly established. METHODS Studies evaluating clinical outcomes of DOACs (including direct Xa inhibitors and direct thrombin inhibitors) or PAR-1 antagonists in addition to standard antiplatelet therapy in patients with recent ACS, published before Nov 2014, were screen. Eleven double blind, placebo-controlled, randomized clinical studies including 46782 patients were identified. RESULTS The study revealed an up to 3-fold increased risk of hemorrhagic stroke in patients receiving DOACs (OR 3.45, 95% CI 1.62 to 7.37, P=0.001, and I(2)=0%) or PAR-1 antagonists (OR 2.60, 95% CI 1.18 to 5.69, P=0.02, and I(2)=0%) in addition to antiplatelet therapy compared to those with antiplatelet therapy alone. Despite a moderate but significant reduction of composite death/MI/stroke was observed in patients with additional DOACs (OR 0.86, 95% CI 0.78 to 0.94, P=0.002, and I(2)=0%) or PAR-1 antagonists (OR 0.89, 95% CI 0.80 to 0.98, P=0.02, and I(2)=0%), due to the remarkably increased major bleeding risks, overall net clinical outcomes (death/MI/stroke/major bleeding) did not differ between patients with or without additional DOACs (OR 0.99, 95% CI 0.91 to 1.09, P=0.88, and I(2)=0%) or PAR-1 antagonists (OR 0.98, 95% CI 0.91 to 1.05, P=0.55, and I(2)=0%). CONCLUSIONS In patients with ACS, the addition of DOACs or PAR-1 antagonists to antiplatelet therapy led to a modest but significant reduction in composite efficacy outcome at the cost of a substantial increase in hemorrhagic stroke and major bleeding events.
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Hong KS, Kim BJ, Lee JY, Kwon SU. Rationale and design of the PreventIon of CArdiovascular events in iSchemic Stroke patients with high risk of cerebral hemOrrhage (PICASSO) study: A randomized controlled trial. Int J Stroke 2015; 10:1153-8. [PMID: 26044566 DOI: 10.1111/ijs.12519] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 03/08/2015] [Indexed: 11/30/2022]
Abstract
RATIONALE Prior intracerebral haemorrhage and cerebral microbleeds may increase the risk of haemorrhagic stroke. However, the optimal long-term antiplatelet therapy and lipid management in these patients remain unclear. AIM PreventIon of CArdiovascular events in iSchemic Stroke patients with high risk of cerebral hemOrrhage was designed to compare cilostazol and aspirin and to assess the effect of adding probucol, a lipid-lowering and anti-oxidative agent, in patients at high risk of haemorrhagic stroke. SAMPLE SIZE ESTIMATE The projected sample size is 1600 patients with at least 12 months of follow-up. METHODS AND DESIGN PreventIon of CArdiovascular events in iSchemic Stroke patients with high risk of cerebral hemOrrhage is a randomized trial involving 67 institutes from 3 countries. Patients with non-cardioembolic ischemic stroke or transient ischemic attack within 180 days and with prior intracerebral haemorrhage or multiple cerebral microbleeds on gradient echo imaging are eligible. Enrolled patients are simultaneously randomized in a 2 × 2 factorial design: double-blind for cilostazol 200 mg/day vs. aspirin 100 mg/day, and an open-label, blind end-point evaluation for probucol 500 mg/day vs. non-probucol. STUDY OUTCOMES The co-primary end-points are the safety end-point of haemorrhagic stroke and the efficacy end-point of a composite of stroke, myocardial infarction, or vascular death. Time-to-event will be analyzed separately for each intervention: superiority testing for the safety of cilostazol over aspirin as well as the efficacy of probucol over non-probucol, and non-inferiority testing for the efficacy of cilostazol to aspirin. DISCUSSION PreventIon of CArdiovascular events in iSchemic Stroke patients with high risk of cerebral hemOrrhage is the largest secondary stroke prevention trial for informing antiplatelet therapy and lipid management in patients at high risk of haemorrhagic stroke.
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Affiliation(s)
- Keun-Sik Hong
- Department of Neurology, Inje University Ilsan Paik Hospital, Goyang, Korea
| | - Bum Joon Kim
- Department of Neurology, Asan Medical Center, University of Ulsan, Seoul, Korea
| | - Jun-Young Lee
- Department of Biostatistics, College of Medicine, Korea University, Seoul, Korea
| | - Sun U Kwon
- Department of Neurology, Asan Medical Center, University of Ulsan, Seoul, Korea
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Parmodulins inhibit thrombus formation without inducing endothelial injury caused by vorapaxar. Blood 2015; 125:1976-85. [PMID: 25587041 DOI: 10.1182/blood-2014-09-599910] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Protease-activated receptor-1 (PAR1) couples the coagulation cascade to platelet activation during myocardial infarction and to endothelial inflammation during sepsis. This receptor demonstrates marked signaling bias. Its activation by thrombin stimulates prothrombotic and proinflammatory signaling, whereas its activation by activated protein C (APC) stimulates cytoprotective and antiinflammatory signaling. A challenge in developing PAR1-targeted therapies is to inhibit detrimental signaling while sparing beneficial pathways. We now characterize a novel class of structurally unrelated small-molecule PAR1 antagonists, termed parmodulins, and compare the activity of these compounds to previously characterized compounds that act at the PAR1 ligand-binding site. We find that parmodulins target the cytoplasmic face of PAR1 without modifying the ligand-binding site, blocking signaling through Gαq but not Gα13 in vitro and thrombus formation in vivo. In endothelium, parmodulins inhibit prothrombotic and proinflammatory signaling without blocking APC-mediated pathways or inducing endothelial injury. In contrast, orthosteric PAR1 antagonists such as vorapaxar inhibit all signaling downstream of PAR1. Furthermore, exposure of endothelial cells to nanomolar concentrations of vorapaxar induces endothelial cell barrier dysfunction and apoptosis. These studies demonstrate how functionally selective antagonism can be achieved by targeting the cytoplasmic face of a G-protein-coupled receptor to selectively block pathologic signaling while preserving cytoprotective pathways.
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Hart RG, Halperin JL, Weitz JI. Vorapaxar, combination antiplatelet therapy, and stroke. J Am Coll Cardiol 2014; 64:2327-9. [PMID: 25465418 DOI: 10.1016/j.jacc.2014.09.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 09/08/2014] [Indexed: 10/24/2022]
Affiliation(s)
- Robert G Hart
- Population Health Research Institute, Hamilton Health Sciences, Department of Medicine (Neurology), McMaster University, Hamilton, Ontario, Canada.
| | - Jonathan L Halperin
- Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, Mount Sinai Medical Center, New York, New York
| | - Jeffrey I Weitz
- Thrombosis and Atherosclerosis Research Institute, Hamilton Health Sciences, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
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Thrombin Receptor Protease-Activated Receptor 4 Is a Key Regulator of Exaggerated Intimal Thickening in Diabetes Mellitus. Circulation 2014; 130:1700-11. [DOI: 10.1161/circulationaha.113.007590] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Background—
Diabetes mellitus predisposes to thrombotic and proliferative vascular remodeling, to which thrombin contributes via activation of protease-activated receptor (PAR) 1. However, the use of PAR-1 inhibitors to suppress remodeling may be limited by severe bleeding. We recently reported upregulation of an additional thrombin receptor, PAR-4, in human vascular smooth muscle cells exposed to high glucose and have now examined PAR-4 as a novel mediator linking hyperglycemia, hypercoagulation, and vascular remodeling in diabetes mellitus.
Methods and Results—
PAR-4 expression was increased in carotid atherectomies and saphenous vein specimens from diabetic versus nondiabetic patients and in aorta and carotid arteries from streptozotocin-diabetic versus nondiabetic C57BL/6 mice. Vascular PAR-1 mRNA was not increased in diabetic mice. Ligated carotid arteries from diabetic mice developed more extensive neointimal hyperplasia and showed greater proliferation than arteries from nondiabetic mice. The augmented remodeling response was absent in diabetic mice deficient in PAR-4. At the cellular level, PAR-4 expression was controlled via the mRNA stabilizing actions of human antigen R, which accounted for the stimulatory actions of high glucose, angiotensin II, and H
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on PAR-4 expression, whereas cicaprost via protein kinase A activation counteracted this effect.
Conclusions—
PAR-4 appears to play a hitherto unsuspected role in diabetic vasculopathy. The development of PAR-4 inhibitors might serve to limit mainly proliferative processes in restenosis-prone diabetic patients, particularly those patients in whom severe bleeding attributed to selective PAR-1 blockade or complete thrombin inhibition must be avoided or those who do not require anticoagulation.
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15
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van den Biggelaar M, Hernández-Fernaud JR, van den Eshof BL, Neilson LJ, Meijer AB, Mertens K, Zanivan S. Quantitative phosphoproteomics unveils temporal dynamics of thrombin signaling in human endothelial cells. Blood 2014; 123:e22-36. [PMID: 24501219 PMCID: PMC3962174 DOI: 10.1182/blood-2013-12-546036] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 01/28/2014] [Indexed: 12/19/2022] Open
Abstract
Thrombin is the key serine protease of the coagulation cascade and a potent trigger of protease-activated receptor 1 (PAR1)-mediated platelet aggregation. In recent years, PAR1 has become an appealing target for anticoagulant therapies. However, the inhibitors that have been developed so far increase bleeding risk in patients, likely because they interfere with endogenous PAR1 signaling in the endothelium. Because of its complexity, thrombin-induced signaling in endothelial cells has remained incompletely understood. Here, we have combined stable isotope amino acids in cell culture, affinity-based phosphopeptide enrichment, and high-resolution mass spectrometry and performed a time-resolved analysis of the thrombin-induced signaling in human primary endothelial cells. We identified 2224 thrombin-regulated phosphorylation sites, the majority of which have not been previously related to thrombin. Those sites were localized on proteins that are novel to thrombin signaling, but also on well-known players such as PAR1, Rho-associated kinase 2, phospholipase C, and proteins related to actin cytoskeleton, cell-cell junctions, and Weibel-Palade body release. Our study provides a unique resource of phosphoproteins and phosphorylation sites that may generate novel insights into an intimate understanding of thrombin-mediated PAR signaling and the development of improved PAR1 antagonists that affect platelet but not endothelial cell function.
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Ungerer M, Münch G. Novel antiplatelet drugs in clinical development. Thromb Haemost 2013; 110:868-75. [PMID: 24108565 DOI: 10.1160/th13-02-0084] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 09/04/2013] [Indexed: 01/13/2023]
Abstract
The clinical value of antiplatelet compounds strongly depends on the benefit-risk balance between their anti-thrombotic effects and the bleeding risk they incur. This ratio is especially important in the treatment of cerebro-vascular disease. Several novel compounds in clinical development hold promise to improve this benefit-risk ratio.
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Affiliation(s)
- M Ungerer
- M. Ungerer, Advancecor GmbH, Fraunhofer Str. 17, 82152 Martinsried, Germany, E-mail:
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17
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Angiolillo DJ, Ferreiro JL. Antiplatelet and anticoagulant therapy for atherothrombotic disease: the role of current and emerging agents. Am J Cardiovasc Drugs 2013; 13:233-50. [PMID: 23613159 DOI: 10.1007/s40256-013-0022-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Coronary atherothrombotic disease, including chronic stable angina and acute coronary syndromes (ACS), is associated with significant global burden. The acute clinical manifestations of atherothrombotic disease are mediated by occlusive arterial thrombi that impair tissue perfusion and are composed of a core of aggregated platelets, generated by platelet activation, and a superimposed fibrin mesh produced by the coagulation cascade. Long-term antithrombotic therapies, namely oral antiplatelet agents and anticoagulants, have demonstrated variable clinical effects. Aspirin and P2Y12 adenosine diphosphate (ADP) receptor antagonists have been shown to reduce the risk for thrombosis and ischaemic events by blocking the thromboxane (Tx) A2 and platelet P2Y12 activation pathways, respectively, whereas the benefits of oral anticoagulants have not been consistently documented. However, even in the presence of aspirin and a P2Y12 receptor antagonist, the risk for ischaemic events remains substantial because platelet activation continues via pathways independent of TxA2 and ADP, most notably the protease-activated receptor (PAR)-1 platelet activation pathway stimulated by thrombin. Emerging antithrombotic therapies include those targeting the platelet, such as the new P2Y12 antagonists and a novel class of oral PAR-1 antagonists, and those inhibiting the coagulation cascade, such as the new direct factor Xa antagonists, the direct thrombin inhibitors, and a novel class of factor IX inhibitors. The role of emerging antiplatelet agents and anticoagulants in the long-term management of patients with atherothrombotic disease will be determined by the balance of efficacy and safety in large ongoing clinical trials.
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