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Katsaras G, Gialamprinou D, Kontovazainitis CG, Psaroulaki E, Mitsiakos G. Neonatal hemostasis and the use of thromboelastography/rotational thromboelastometry in the neonatal period. Minerva Pediatr (Torino) 2024; 76:425-438. [PMID: 37166777 DOI: 10.23736/s2724-5276.23.07214-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Developmental hemostasis refers to age-related alterations related to the progressive maturation of the hemostatic system. Although the conventional coagulation tests, such as prothrombin time (PT) and activated partial thromboplastin time (aPTT), are indeed helpful in coagulation workup, they do not accurately delineate the hemostasis in vivo. The viscoelastic tests, namely thromboelastography (TEG) and rotational thromboelastometry (ROTEM), seem to reflect hemostasis more accurately since they measure various clot parameters without excluding the cellular coagulation components. TEG and ROTEM have shown redaction in blood product administration when used in therapeutic algorithms in older children and adults, but their use in neonates is limited. This review summarizes the current literature regarding using these tests in the neonatal population. Several studies tried to resolve the lack of neonatal reference values of the TEG/ROTEM parameters by publishing neonatal reference ranges for various gestational age groups. Moreover, few studies concerning therapeutic hypothermia, neonates undergoing surgery, and critically ill neonates have shown some predictive value of these tests regarding bleeding events. Even though their results seem promising, larger studies of higher quality are needed to clarify any discrepancies and point out whether these tests have significant predictive value. In conclusion, viscoelastic tests need to be increasingly part of the NICUs' clinical routine and should be used along with conventional coagulation tests in transfusion therapy.
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Affiliation(s)
- Georgios Katsaras
- Department of Pediatrics, Hospital Unit of Edessa, General Hospital of Pella, Edessa, Greece -
- Second Neonatal Department and Neonatal Intensive Care Unit (NICU), Aristotle University of Thessaloniki, Papageorgiou Hospital, Thessaloniki, Greece -
| | - Dimitra Gialamprinou
- Second Neonatal Department and Neonatal Intensive Care Unit (NICU), Aristotle University of Thessaloniki, Papageorgiou Hospital, Thessaloniki, Greece
| | - Christos-Georgios Kontovazainitis
- Second Neonatal Department and Neonatal Intensive Care Unit (NICU), Aristotle University of Thessaloniki, Papageorgiou Hospital, Thessaloniki, Greece
| | - Evdokia Psaroulaki
- Department of Pediatrics, Hospital Unit of Edessa, General Hospital of Pella, Edessa, Greece
| | - Georgios Mitsiakos
- Second Neonatal Department and Neonatal Intensive Care Unit (NICU), Aristotle University of Thessaloniki, Papageorgiou Hospital, Thessaloniki, Greece
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2
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Phenotypic and genotypic characterization of two factor VII deficiency patients from southeastern China. Blood Coagul Fibrinolysis 2022; 33:468-472. [PMID: 35867939 DOI: 10.1097/mbc.0000000000001145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The congenital factor VII deficiency (FVIID) is a rare autosomal recessive haemorrhagic disease caused by mutations in the F7 gene. The aim of this study was to identify the mutations causing FVII deficiency and explain the genotype-phenotype association in two unrelated Chinese patients. Mutation detection was conducted by sequencing the whole F7 gene coding exons, exon-intron boundaries and the untranslated regions of 3' and 5'. Then, the genetic information was analyzed to predict the structures of the mutated proteins. A total of four different mutations were detected, including three missense mutations (c.64G>A, c.286A>G, and c.722C>A, predicting p.Gly22Ser, p.Arg96Gly, p.Thr241Asn, respectively) and one insertion mutation (c.204_205insCGGC, predicting p. Leu68Argfs ∗ 37), among which two were reported for the first time (p.Arg96Gly, p.Leu68Argfs ∗ 37). Multiple sequence alignments of FVII protein revealed that the residues p.Arg96 and p.Thr241 were highly conserved. The novel missense mutation p.Arg96Gly was determined as damaging with online software Polyphen-2 and SIFT. We investigated two asymptomatic patients diagnosed with severe FVII deficiency and identified two novel mutations (the mutation p.Arg96Gly and p.Leu68Argfs ∗ 37). Identification of the F7 mutations was important for genetic counseling and accurate prediction of the inheritance pattern.
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Al-Koussa H, AlZaim I, El-Sabban ME. Pathophysiology of Coagulation and Emerging Roles for Extracellular Vesicles in Coagulation Cascades and Disorders. J Clin Med 2022; 11:jcm11164932. [PMID: 36013171 PMCID: PMC9410115 DOI: 10.3390/jcm11164932] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 05/20/2022] [Indexed: 11/16/2022] Open
Abstract
The notion of blood coagulation dates back to the ancient Greek civilization. However, the emergence of innovative scientific discoveries that started in the seventeenth century formulated the fundamentals of blood coagulation. Our understanding of key coagulation processes continues to evolve, as novel homeostatic and pathophysiological aspects of hemostasis are revealed. Hemostasis is a dynamic physiological process, which stops bleeding at the site of injury while maintaining normal blood flow within the body. Intrinsic and extrinsic coagulation pathways culminate in the homeostatic cessation of blood loss, through the sequential activation of the coagulation factors. Recently, the cell-based theory, which combines these two pathways, along with newly discovered mechanisms, emerged to holistically describe intricate in vivo coagulation mechanisms. The complexity of these mechanisms becomes evident in coagulation diseases such as hemophilia, Von Willebrand disease, thrombophilia, and vitamin K deficiency, in which excessive bleeding, thrombosis, or unnecessary clotting, drive the development and progression of diseases. Accumulating evidence implicates cell-derived and platelet-derived extracellular vesicles (EVs), which comprise microvesicles (MVs), exosomes, and apoptotic bodies, in the modulation of the coagulation cascade in hemostasis and thrombosis. As these EVs are associated with intercellular communication, molecular recycling, and metastatic niche creation, emerging evidence explores EVs as valuable diagnostic and therapeutic approaches in thrombotic and prothrombotic diseases.
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Affiliation(s)
- Houssam Al-Koussa
- Department of Pharmacology and Toxicology, Faculty of Medicine, The American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
| | - Ibrahim AlZaim
- Department of Pharmacology and Toxicology, Faculty of Medicine, The American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, The American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
| | - Marwan E. El-Sabban
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, The American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
- Correspondence: ; Tel.: +961-01-350-000 (ext. 4765)
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Pelzl L, Singh A, Funk J, Witzemann A, Marini I, Zlamal J, Weich K, Abou-Khalel W, Hammer S, Uzun G, Althaus K, Bakchoul T. Antibody-mediated procoagulant platelet formation in COVID-19 is AKT dependent. J Thromb Haemost 2022; 20:387-398. [PMID: 34752677 PMCID: PMC8646637 DOI: 10.1111/jth.15587] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Thromboembolic events are frequently reported in patients infected with the SARS-CoV-2. Recently, we observed that platelets from patients with severe COVID-19 infection express procoagulant phenotype. The molecular mechanisms that induce the generation of procoagulant platelets in COVID-19 patients are not completely understood. OBJECTIVES In this study, we investigated the role of AKT (also known as Protein Kinase B), which is the major downstream effector of PI3K (phosphoinositid-3-kinase) (PI3K/AKT) signaling pathway in platelets from patients with COVID-19. PATIENTS AND METHODS Platelets, Sera and IgG from COVID-19 patients who were admitted to the intensive care unit (ICU) were analyzed by flow cytometry as well as western blot and adhesion assays. RESULTS Platelets from COVID-19 patients showed significantly higher levels of phosphorylated AKT, which was correlated with CD62p expression and phosphatidylserine (PS) externalization. In addition, healthy platelets incubated with sera or IgGs from ICU COVID-19 patients induced phosphorylation of PI3K and AKT and were dependent on Fc-gamma-RIIA (FcγRIIA). In contrast, ICU COVID-19 sera mediated generation of procoagulant platelets was not dependent on GPIIb/IIIa. Interestingly, the inhibition of phosphorylation of both proteins AKT and PI3K prevented the generation of procoagulant platelets. CONCLUSIONS Our study shows that pAKT/AKT signaling pathway is associated with the formation of procoagulant platelets in severe COVID-19 patients without integrin GPIIb/IIIa engagement. The inhibition of PI3K/AKT phosphorylation might represent a promising strategy to reduce the risk for thrombosis in patients with severe COVID-19.
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Affiliation(s)
- Lisann Pelzl
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
| | - Anurag Singh
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
| | - Jonas Funk
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
| | - Andreas Witzemann
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
| | - Irene Marini
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
| | - Jan Zlamal
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
| | - Karoline Weich
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
- Centre for Clinical Transfusion Medicine, University Hospital of Tuebingen, Tuebingen, Germany
| | - Wissam Abou-Khalel
- Centre for Clinical Transfusion Medicine, University Hospital of Tuebingen, Tuebingen, Germany
| | - Stefanie Hammer
- Centre for Clinical Transfusion Medicine, University Hospital of Tuebingen, Tuebingen, Germany
| | - Guenalp Uzun
- Centre for Clinical Transfusion Medicine, University Hospital of Tuebingen, Tuebingen, Germany
| | - Karina Althaus
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
- Centre for Clinical Transfusion Medicine, University Hospital of Tuebingen, Tuebingen, Germany
| | - Tamam Bakchoul
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, Tuebingen, Germany
- Centre for Clinical Transfusion Medicine, University Hospital of Tuebingen, Tuebingen, Germany
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The pleiotropic effects of antithrombotic drugs in the metabolic-cardiovascular-neurodegenerative disease continuum: impact beyond reduced clotting. Clin Sci (Lond) 2021; 135:1015-1051. [PMID: 33881143 DOI: 10.1042/cs20201445] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/07/2021] [Accepted: 04/13/2021] [Indexed: 12/25/2022]
Abstract
Antithrombotic drugs are widely used for primary and secondary prevention, as well as treatment of many cardiovascular disorders. Over the past few decades, major advances in the pharmacology of these agents have been made with the introduction of new drug classes as novel therapeutic options. Accumulating evidence indicates that the beneficial outcomes of some of these antithrombotic agents are not solely related to their ability to reduce thrombosis. Here, we review the evidence supporting established and potential pleiotropic effects of four novel classes of antithrombotic drugs, adenosine diphosphate (ADP) P2Y12-receptor antagonists, Glycoprotein IIb/IIIa receptor Inhibitors, and Direct Oral Anticoagulants (DOACs), which include Direct Factor Xa (FXa) and Direct Thrombin Inhibitors. Specifically, we discuss the molecular evidence supporting such pleiotropic effects in the context of cardiovascular disease (CVD) including endothelial dysfunction (ED), atherosclerosis, cardiac injury, stroke, and arrhythmia. Importantly, we highlight the role of DOACs in mitigating metabolic dysfunction-associated cardiovascular derangements. We also postulate that DOACs modulate perivascular adipose tissue inflammation and thus, may reverse cardiovascular dysfunction early in the course of the metabolic syndrome. In this regard, we argue that some antithrombotic agents can reverse the neurovascular damage in Alzheimer's and Parkinson's brain and following traumatic brain injury (TBI). Overall, we attempt to provide an up-to-date comprehensive review of the less-recognized, beneficial molecular aspects of antithrombotic therapy beyond reduced thrombus formation. We also make a solid argument for the need of further mechanistic analysis of the pleiotropic effects of antithrombotic drugs in the future.
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Ziliotto N, Bernardi F, Jakimovski D, Zivadinov R. Coagulation Pathways in Neurological Diseases: Multiple Sclerosis. Front Neurol 2019; 10:409. [PMID: 31068896 PMCID: PMC6491577 DOI: 10.3389/fneur.2019.00409] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 04/04/2019] [Indexed: 12/11/2022] Open
Abstract
Significant progress has been made in understanding the complex interactions between the coagulation system and inflammation and autoimmunity. Increased blood-brain-barrier (BBB) permeability, a key event in the pathophysiology of multiple sclerosis (MS), leads to the irruption into the central nervous system of blood components that include virtually all coagulation/hemostasis factors. Besides their cytotoxic deposition and role as a possible trigger of the coagulation cascade, hemostasis components cause inflammatory response and immune activation, sustaining neurodegenerative events in MS. Early studies showing the contribution of altered hemostasis in the complex pathophysiology of MS have been strengthened by recent studies using methodologies that permitted deeper investigation. Fibrin(ogen), an abundant protein in plasma, has been identified as a key contributor to neuroinflammation. Perturbed fibrinolysis was found to be a hallmark of progressive MS with abundant cortical fibrin(ogen) deposition. The immune-modulatory function of the intrinsic coagulation pathway still remains to be elucidated in MS. New molecular details in key hemostasis components participating in MS pathophysiology, and particularly involved in inflammatory and immune responses, could favor the development of novel therapeutic targets to ameliorate the evolution of MS. This review article introduces essential information on coagulation factors, inhibitors, and the fibrinolytic pathway, and highlights key aspects of their involvement in the immune system and inflammatory response. It discusses how hemostasis components are (dys)regulated in MS, and summarizes histopathological post-mortem human brain evidence, as well as cerebrospinal fluid, plasma, and serum studies of hemostasis and fibrinolytic pathways in MS. Studies of disease-modifying treatments as potential modifiers of coagulation factor levels, and case reports of autoimmunity affecting hemostasis in MS are also discussed.
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Affiliation(s)
- Nicole Ziliotto
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.,Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, Buffalo Neuroimaging Analysis Center, University at Buffalo, State University of New York, Buffalo, NY, United States
| | - Francesco Bernardi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Dejan Jakimovski
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, Buffalo Neuroimaging Analysis Center, University at Buffalo, State University of New York, Buffalo, NY, United States
| | - Robert Zivadinov
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, Buffalo Neuroimaging Analysis Center, University at Buffalo, State University of New York, Buffalo, NY, United States.,Clinical Translational Science Institute, Center for Biomedical Imaging, University at Buffalo, State University of New York, Buffalo, NY, United States
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7
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O'Donnell JS, O'Sullivan JM, Preston RJS. Advances in understanding the molecular mechanisms that maintain normal haemostasis. Br J Haematol 2019; 186:24-36. [DOI: 10.1111/bjh.15872] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- James S. O'Donnell
- Haemostasis Research Group Department of Molecular and Cellular Therapeutics Irish Centre for Vascular Biology Royal College of Surgeons in Ireland Dublin Ireland
| | - Jamie M. O'Sullivan
- Haemostasis Research Group Department of Molecular and Cellular Therapeutics Irish Centre for Vascular Biology Royal College of Surgeons in Ireland Dublin Ireland
| | - Roger J. S. Preston
- Haemostasis Research Group Department of Molecular and Cellular Therapeutics Irish Centre for Vascular Biology Royal College of Surgeons in Ireland Dublin Ireland
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9
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Experimental hypercoagulable state induced by tissue factor expression in monocyte-derived dendritic cells and its modulation by C1 inhibitor. J Thromb Thrombolysis 2018; 46:219-226. [PMID: 29860607 DOI: 10.1007/s11239-018-1688-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
The crosstalk between immune and coagulation systems plays pivotal roles in host defense, which may involve monocyte-derived dendritic cells (moDCs). Our objectives were to elucidate the role of moDCs in coagulation under inflammatory conditions and the involvement of the complement system. We assessed the effects of lipopolysaccharide (LPS)-stimulated moDCs on coagulation using whole blood thromboelastometry in the presence of complement inhibitors. The sum of clotting time and clot formation time (CT plus CFT) in whole blood thromboelastometry was significantly more reduced in the presence of moDCs than in the absence of monocytes or moDCs and in the presence of monocytes, indicating a more potent coagulability of moDCs. The mRNA expression of coagulation-related proteins in moDCs was analyzed by quantitative PCR, which showed an increase only in the mRNA levels of tissue factor (TF). TF protein expression was assessed by western blot analysis and an activity assay, revealing higher TF expression in moDCs than that in monocytes. The in vitro moDC-associated hypercoagulable state was suppressed by a TF-neutralizing antibody, whereas LPS enhanced the in vitro hypercoagulation further. C1 inhibitor suppressed the in vitro LPS-enhanced whole blood hypercoagulability in the presence of moDCs and the increased TF expression in moDCs. These results suggest a significant role of moDCs and the complement system through TF expression in a hypercoagulable state under inflammatory conditions and demonstrate the suppressive effects of C1 inhibitor on moDC-associated hypercoagulation.
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10
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Tiscia G, Favuzzi G, Chinni E, Colaizzo D, Fischetti L, Intrieri M, Margaglione M, Grandone E. Factor VII deficiency: a novel missense variant and genotype-phenotype correlation in patients from Southern Italy. Hum Genome Var 2017; 4:17048. [PMID: 29104756 PMCID: PMC5667183 DOI: 10.1038/hgv.2017.48] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/23/2017] [Accepted: 09/10/2017] [Indexed: 11/17/2022] Open
Abstract
This study aimed at attempting to correlate genotype and phenotype in factor VII deficiency. Here, we present molecular and clinical findings of 10 patients with factor VII deficiency. From 2013 to 2016, 10 subjects were referred to our center because of a prolonged prothrombin time identified during routine or presurgery examinations or after a laboratory assessment of a bleeding episode. Mutation characterization was performed using the bioinformatics applications PROMO, SIFT, and Polyphen-2. Structural changes in the factor VII protein were analyzed using the SPDB viewer tool. Of the 10 variants we identified, 1 was responsible for a novel missense change (c.1199G>C, p.Cys400Ser); in 2 cases we identified the c.-54G>A and c.509G>A (p.Arg170His) polymorphic variants in the 5′-upstream region of the factor VII gene and exon 6, respectively. To our knowledge, neither of these polymorphic variants has been described previously in factor VII-deficient patients. In silico predictions showed differences in binding sites for transcription factors caused by the c.-54G>A variant and a probable damaging effect of the p.Cys400Ser missense change on factor VII active conformation, leading to breaking of the Cys400-Cys428 disulfide bridge. Our findings further suggest that, independently of factor VII levels and of variants potentially affecting factor VII levels, environmental factors, e.g., trauma, could heavily influence the clinical phenotype of factor VII-deficient patients.
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Affiliation(s)
- Giovanni Tiscia
- Atherosclerosis and Thrombosis Unit, I.R.C.C.S. 'Casa Sollievo della Sofferenza', San Giovanni Rotondo (Foggia), Italy
| | - Giovanni Favuzzi
- Atherosclerosis and Thrombosis Unit, I.R.C.C.S. 'Casa Sollievo della Sofferenza', San Giovanni Rotondo (Foggia), Italy
| | - Elena Chinni
- Atherosclerosis and Thrombosis Unit, I.R.C.C.S. 'Casa Sollievo della Sofferenza', San Giovanni Rotondo (Foggia), Italy
| | - Donatella Colaizzo
- Atherosclerosis and Thrombosis Unit, I.R.C.C.S. 'Casa Sollievo della Sofferenza', San Giovanni Rotondo (Foggia), Italy
| | - Lucia Fischetti
- Atherosclerosis and Thrombosis Unit, I.R.C.C.S. 'Casa Sollievo della Sofferenza', San Giovanni Rotondo (Foggia), Italy
| | - Mariano Intrieri
- Department of Medicine and Health Sciences 'Vincenzo Tiberio', University of Molise, Campobasso, Italy
| | | | - Elvira Grandone
- Atherosclerosis and Thrombosis Unit, I.R.C.C.S. 'Casa Sollievo della Sofferenza', San Giovanni Rotondo (Foggia), Italy
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Moon JY, Nagaraju D, Franchi F, Rollini F, Angiolillo DJ. The role of oral anticoagulant therapy in patients with acute coronary syndrome. Ther Adv Hematol 2017; 8:353-366. [PMID: 29204262 DOI: 10.1177/2040620717733691] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 09/04/2017] [Indexed: 12/16/2022] Open
Abstract
Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor antagonist represents the current standard of care to prevent atherothrombotic recurrences in patients with acute coronary syndrome (ACS). However, despite the use of DAPT, the recurrence rate of cardiovascular ischemic events still remains high. This persistent risk may be in part attributed to the sustained activation of the coagulation cascade leading to generation of thrombin, which may continue to play a key role in thrombus formation. The use of vitamin K antagonists (VKAs) as a strategy to reduce atherothrombotic recurrences after an ACS has been previously tested, leading to overall unfavorable outcomes due to the high risk of bleeding complications. The recent introduction of non-VKA oral anticoagulants (NOACs), characterized by a better safety profile and ease of use compared with VKA, has led to a reappraisal of the use of oral anticoagulant therapy for secondary prevention in ACS patients. The present article provides an overview of the rationale and prognostic role of oral anticoagulant therapy in ACS patients as well as recent updated clinical data, in particular with NOACs, in the field and future perspectives on this topic.
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Affiliation(s)
- Jae Youn Moon
- Division of Cardiology, University of Florida College of Medicine - Jacksonville, FL, USA Department of Cardiology, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| | - Deepa Nagaraju
- Division of Cardiology, University of Florida College of Medicine - Jacksonville, FL, USA
| | - Francesco Franchi
- Division of Cardiology, University of Florida College of Medicine - Jacksonville, FL, USA
| | - Fabiana Rollini
- Division of Cardiology, University of Florida College of Medicine - Jacksonville, FL, USA
| | - Dominick J Angiolillo
- University of Florida College of Medicine - Jacksonville, 655 West 8th Street, Jacksonville, FL 32209, USA
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12
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Campbell RA, Vieira-de-Abreu A, Rowley JW, Franks ZG, Manne BK, Rondina MT, Kraiss LW, Majersik JJ, Zimmerman GA, Weyrich AS. Clots Are Potent Triggers of Inflammatory Cell Gene Expression: Indications for Timely Fibrinolysis. Arterioscler Thromb Vasc Biol 2017; 37:1819-1827. [PMID: 28775073 DOI: 10.1161/atvbaha.117.309794] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 07/21/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Blood vessel wall damage often results in the formation of a fibrin clot that traps inflammatory cells, including monocytes. The effect of clot formation and subsequent lysis on the expression of monocyte-derived genes involved in the development and progression of ischemic stroke and other vascular diseases, however, is unknown. Determine whether clot formation and lysis regulates the expression of human monocyte-derived genes that modulate vascular diseases. APPROACH AND RESULTS We performed next-generation RNA sequencing on monocytes extracted from whole blood clots and using a purified plasma clot system. Numerous mRNAs were differentially expressed by monocytes embedded in clots compared with unclotted controls, and IL-8 (interleukin 8) and MCP-1 (monocyte chemoattractant protein-1) were among the upregulated transcripts in both models. Clotted plasma also increased expression of IL-8 and MCP-1, which far exceeded responses observed in lipopolysaccharide-stimulated monocytes. Upregulation of IL-8 and MCP-1 occurred in a thrombin-independent but fibrin-dependent manner. Fibrinolysis initiated shortly after plasma clot formation (ie, 1-2 hours) reduced the synthesis of IL-8 and MCP-1, whereas delayed fibrinolysis was far less effective. Consistent with these in vitro models, monocytes embedded in unresolved thrombi from patients undergoing thrombectomy stained positively for IL-8 and MCP-1. CONCLUSIONS These findings demonstrate that clots are potent inducers of monocyte gene expression and that timely fibrinolysis attenuates inflammatory responses, specifically IL-8 and MCP-1. Dampening of inflammatory gene expression by timely clot lysis may contribute to the clinically proven efficacy of fibrinolytic drug treatment within hours of stroke onset.
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Affiliation(s)
- Robert A Campbell
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City.
| | - Adriana Vieira-de-Abreu
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
| | - Jesse W Rowley
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
| | - Zechariah G Franks
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
| | - Bhanu Kanth Manne
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
| | - Matthew T Rondina
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
| | - Larry W Kraiss
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
| | - Jennifer J Majersik
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
| | - Guy A Zimmerman
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
| | - Andrew S Weyrich
- From the Program in Molecular Medicine (R.A.C., J.W.R., Z.G.F., B.K.M., M.T.R., L.W.K., A.S.W.) and Departments of Internal Medicine (R.A.C., A.V.-d.-A., J.W.R., M.T.R., G.A.Z., A.S.W.), Surgery (L.W.K.), and Neurology (J.J.M.), University of Utah, Salt Lake City
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13
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Scherillo M, Cirillo P, Formigli D, Bonzani G, Calabrò P, Capogrosso P, Farina R, Lanzillo T, Mascia F, Mauro C, Tuccillo B, Bellis A, Bianchi R, Cimmino G, Piro O, Ravera A, Scotto di Uccio F, Tammaro P, Vetrano A, Trimarco B. Antiplatelet Therapy for Non-ST-Segment Elevation Myocardial Infarction in Complex "Real" Clinical Scenarios: A Consensus Document of the "Campania NSTEMI Study Group". Angiology 2017; 68:598-607. [PMID: 28660806 DOI: 10.1177/0003319716676721] [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] [Indexed: 12/22/2022]
Abstract
The incidence of ST-segment elevation myocardial infarction (STEMI) has significantly decreased. Conversely, the rate of non-STEMI (NSTEMI) has increased. Patients with NSTEMI have lower short-term mortality compared to patients with STEMI, whereas at long-term follow-up, the mortality becomes comparable. This might be due to the differences in baseline characteristics, including older age and a greater prevalence of comorbidities in the NSTEMI population. Although antithrombotic strategies used in patients with NSTEMI have been well studied in clinical trials and updated guidelines are available, patterns of use and outcomes in clinical practice are less well described. Thus, a panel of Italian cardiology experts assembled under the auspices of the "Campania NSTEMI Study Group" for comprehensive discussion and consensus development to provide practical recommendations, for both clinical and interventional cardiologists, regarding optimal management of antithrombotic therapy in patients with NSTEMI. This position article presents and discusses various clinical scenarios in patients with NSTEMI or unstable angina, including special subsets (eg, patients aged ≥85 years, patients with chronic renal disease or previous cerebrovascular events, and patients requiring triple therapy or long-term antithrombotic therapy), with the panel recommendations being provided for each scenario.
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Affiliation(s)
- Marino Scherillo
- 1 U.O.C. Cardiologia Interventistica ed UTIC. Azienda Ospedaliera "G.Rummo" di Benevento
| | - Plinio Cirillo
- 2 Division of Cardiology, Department of Advanced Biomedical Sciences, Universitaà di Napoli "Federico II," Napoli, Italy
| | - Dario Formigli
- 1 U.O.C. Cardiologia Interventistica ed UTIC. Azienda Ospedaliera "G.Rummo" di Benevento
| | - Giulio Bonzani
- 3 U.O.C. Cardiologia Interventistica. Azienda Ospedaliera Specialistica dei Colli, Napoli
| | - Paolo Calabrò
- 4 U.O.C. Cardiologia Interventistica ed UTIC. Seconda Università di Napoli, Napoli
| | - Paolo Capogrosso
- 5 U.O.C. Cardiologia ed UTIC, Ospedale San Giovanni Bosco, Napoli
| | - Rosario Farina
- 6 Cardiologia ed UTIC, Ospedale San Giovanni di Dio ed Ruggi d' Aragona, Salerno
| | - Tonino Lanzillo
- 7 Unità operativa di Cardiologia ed UTIC, Ospedale Moscati, Avellino
| | - Franco Mascia
- 8 U.O.C. Cardiologia-UTIC. Ospedale S. Anna e S. Sebastiano, Caserta
| | - Ciro Mauro
- 9 U.O.C. Cardiologia Interventistica ed UTIC. Ospedale Cardarelli, Napoli
| | | | - Alessandro Bellis
- 9 U.O.C. Cardiologia Interventistica ed UTIC. Ospedale Cardarelli, Napoli
| | - Renato Bianchi
- 4 U.O.C. Cardiologia Interventistica ed UTIC. Seconda Università di Napoli, Napoli
| | - Giovanni Cimmino
- 8 U.O.C. Cardiologia-UTIC. Ospedale S. Anna e S. Sebastiano, Caserta
| | - Orlando Piro
- 3 U.O.C. Cardiologia Interventistica. Azienda Ospedaliera Specialistica dei Colli, Napoli
| | - Amelia Ravera
- 6 Cardiologia ed UTIC, Ospedale San Giovanni di Dio ed Ruggi d' Aragona, Salerno
| | | | - Paolo Tammaro
- 5 U.O.C. Cardiologia ed UTIC, Ospedale San Giovanni Bosco, Napoli
| | - Alfredo Vetrano
- 8 U.O.C. Cardiologia-UTIC. Ospedale S. Anna e S. Sebastiano, Caserta
| | - Bruno Trimarco
- 2 Division of Cardiology, Department of Advanced Biomedical Sciences, Universitaà di Napoli "Federico II," Napoli, Italy
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14
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Moon JY, Franchi F, Rollini F, Angiolillo DJ. Role for Thrombin Receptor Antagonism With Vorapaxar in Secondary Prevention of Atherothrombotic Events: From Bench to Bedside. J Cardiovasc Pharmacol Ther 2017; 23:23-37. [PMID: 28565918 DOI: 10.1177/1074248417708617] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In spite of treatment with the current standard of care antiplatelet regimens including dual antiplatelet therapy, recurrence rates of ischemic events remain elevated for high-risk patients with atherosclerotic disease. This may be in part attributed to the fact that other key platelet activation pathways remain uninhibited and can thus continue to trigger platelet activation and lead to thrombotic complications. Thrombin is a powerful inducer of platelet activation and mediates its effects directly on platelets through protease activator receptors (PARs), particularly the PAR-1 subtype, making PAR-1 inhibition an attractive approach for reducing atherothrombotic events. These observations have led to the development of several PAR-1 antagonists. Vorapaxar is a direct inhibitor of PAR-1 and the only agent of this class approved for the prevention of recurrent ischemic events in patients with prior myocardial infarction or peripheral artery disease. In the present manuscript, we present a review of the pathophysiologic role of thrombin on thrombotic complications, the impact of vorapaxar on outcomes, including the most recent updates deriving from clinical trials, as well as future perspectives in the field.
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Affiliation(s)
- Jae Youn Moon
- 1 Division of Cardiology, University of Florida College of Medicine-Jacksonville, Jacksonville, FL, USA
| | - Francesco Franchi
- 1 Division of Cardiology, University of Florida College of Medicine-Jacksonville, Jacksonville, FL, USA
| | - Fabiana Rollini
- 1 Division of Cardiology, University of Florida College of Medicine-Jacksonville, Jacksonville, FL, USA
| | - Dominick J Angiolillo
- 1 Division of Cardiology, University of Florida College of Medicine-Jacksonville, Jacksonville, FL, USA
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15
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Simmons J, Powell M. Acute traumatic coagulopathy: pathophysiology and resuscitation. Br J Anaesth 2016; 117:iii31-iii43. [DOI: 10.1093/bja/aew328] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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16
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Abstract
Although the concept of the coagulation cascade represented a significant advance in the understanding of coagulation and served for many years as a useful model, more recent clinical and experimental observations demonstrate that the cascade/waterfall hypothesis does not fully and completely reflect the events of hemostasis in vivo. The goal of this article is to review the evolution of the theories of coagulation and their proposed models to serve as a tool when reviewing the research and practice literature that was published in the context of these different theories over time.
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Affiliation(s)
- James P Riddel
- Division of Hematology at Children's Hospital and Research Center Oakland, Oakland, California 94609-1809, USA.
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Nimjee SM, Povsic TJ, Sullenger BA, Becker RC. Translation and Clinical Development of Antithrombotic Aptamers. Nucleic Acid Ther 2016; 26:147-55. [PMID: 26882082 PMCID: PMC4900189 DOI: 10.1089/nat.2015.0581] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 01/12/2016] [Indexed: 01/02/2023] Open
Abstract
Thrombosis is a necessary physiological process to protect the body from uncontrolled bleeding. Pathological thrombus formation can lead to devastating clinical events including heart attack, stroke, deep vein thrombosis, pulmonary embolism, and disseminated intravascular coagulation. Numerous drugs have been developed to inhibit thrombosis. These have been targeted to coagulation factors along with proteins and receptors that activate platelets. While these drugs are effective at preventing blood clotting, their major side effect is inadvertent hemorrhage that can result in significant morbidity and mortality. There exists a need for anticoagulants that are not only effective at preventing thrombosis but can also be readily reversed. Aptamers offer a potential solution, representing a new class of drug agents that can be isolated to any protein and where antidote oligonucleotides can be designed based on the sequence of the aptamer. We present a summary of the anticoagulant and antithrombotic aptamers that have been identified and their stage of development and comment on the future of aptamer-based drug development to treat thrombosis.
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Affiliation(s)
- Shahid M. Nimjee
- Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Thomas J. Povsic
- Duke Clinical Research Institute, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Bruce A. Sullenger
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Richard C. Becker
- Department of Medicine, University of Cincinnati Medical Center, Cincinnati, Ohio
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18
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Lincoff AM, Mehran R, Povsic TJ, Zelenkofske SL, Huang Z, Armstrong PW, Steg PG, Bode C, Cohen MG, Buller C, Laanmets P, Valgimigli M, Marandi T, Fridrich V, Cantor WJ, Merkely B, Lopez-Sendon J, Cornel JH, Kasprzak JD, Aschermann M, Guetta V, Morais J, Sinnaeve PR, Huber K, Stables R, Sellers MA, Borgman M, Glenn L, Levinson AI, Lopes RD, Hasselblad V, Becker RC, Alexander JH. Effect of the REG1 anticoagulation system versus bivalirudin on outcomes after percutaneous coronary intervention (REGULATE-PCI): a randomised clinical trial. Lancet 2016; 387:349-356. [PMID: 26547100 DOI: 10.1016/s0140-6736(15)00515-2] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND REG1 is a novel anticoagulation system consisting of pegnivacogin, an RNA aptamer inhibitor of coagulation factor IXa, and anivamersen, a complementary sequence reversal oligonucleotide. We tested the hypothesis that near complete inhibition of factor IXa with pegnivacogin during percutaneous coronary intervention, followed by partial reversal with anivamersen, would reduce ischaemic events compared with bivalirudin, without increasing bleeding. METHODS We did a randomised, open-label, active-controlled, multicentre, superiority trial to compare REG1 with bivalirudin at 225 hospitals in North America and Europe. We planned to randomly allocate 13,200 patients undergoing percutaneous coronary intervention in a 1:1 ratio to either REG1 (pegnivacogin 1 mg/kg bolus [>99% factor IXa inhibition] followed by 80% reversal with anivamersen after percutaneous coronary intervention) or bivalirudin. Exclusion criteria included ST segment elevation myocardial infarction within 48 h. The primary efficacy endpoint was the composite of all-cause death, myocardial infarction, stroke, and unplanned target lesion revascularisation by day 3 after randomisation. The principal safety endpoint was major bleeding. Analysis was by intention to treat. This trial is registered at ClinicalTrials.gov, identifier NCT01848106. The trial was terminated early after enrolment of 3232 patients due to severe allergic reactions. FINDINGS 1616 patients were allocated REG1 and 1616 were assigned bivalirudin, of whom 1605 and 1601 patients, respectively, received the assigned treatment. Severe allergic reactions were reported in ten (1%) of 1605 patients receiving REG1 versus one (<1%) of 1601 patients treated with bivalirudin. The composite primary endpoint did not differ between groups, with 108 (7%) of 1616 patients assigned REG1 and 103 (6%) of 1616 allocated bivalirudin reporting a primary endpoint event (odds ratio [OR] 1·05, 95% CI 0·80-1·39; p=0·72). Major bleeding was similar between treatment groups (seven [<1%] of 1605 receiving REG1 vs two [<1%] of 1601 treated with bivalirudin; OR 3·49, 95% CI 0·73-16·82; p=0·10), but major or minor bleeding was increased with REG1 (104 [6%] vs 65 [4%]; 1·64, 1·19-2·25; p=0·002). INTERPRETATION The reversible factor IXa inhibitor REG1, as currently formulated, is associated with severe allergic reactions. Although statistical power was limited because of early termination, there was no evidence that REG1 reduced ischaemic events or bleeding compared with bivalirudin. FUNDING Regado Biosciences Inc.
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Affiliation(s)
- A Michael Lincoff
- Cleveland Clinic Coordinating Center for Clinical Research (C5Research), Cleveland, OH, USA.
| | | | - Thomas J Povsic
- Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA
| | | | - Zhen Huang
- Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA
| | - Paul W Armstrong
- Canadian VIGOUR Centre, University of Alberta, Edmonton, AB, Canada
| | - P Gabriel Steg
- Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | | | | | | | | | - Marco Valgimigli
- University Hospital of Ferrara, Institute of Cardiology, Ferrara, Italy
| | | | - Viliam Fridrich
- National Institute of Cardiovascular Diseases, Bratislava, Slovakia
| | | | - Bela Merkely
- Semmelweis University Heart and Vascular Center, Budapest, Hungary
| | | | | | | | | | - Victor Guetta
- Heart Institute Sheba Medical Center, Tel Aviv University, Tel Hashomer, Israel
| | | | - Peter R Sinnaeve
- University Hospitals Leuven Campus Gasthuisberg, Leuven, Belgium
| | | | - Rod Stables
- Liverpool Heart & Chest Hospital, Liverpool, UK
| | - Mary Ann Sellers
- Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA
| | - Marilyn Borgman
- Cleveland Clinic Coordinating Center for Clinical Research (C5Research), Cleveland, OH, USA
| | | | - Arnold I Levinson
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Renato D Lopes
- Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA
| | - Vic Hasselblad
- Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA
| | - Richard C Becker
- University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - John H Alexander
- Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA
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19
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Panteleev MA, Dashkevich NM, Ataullakhanov FI. Hemostasis and thrombosis beyond biochemistry: roles of geometry, flow and diffusion. Thromb Res 2015; 136:699-711. [DOI: 10.1016/j.thromres.2015.07.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 07/22/2015] [Accepted: 07/26/2015] [Indexed: 11/16/2022]
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20
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Swanepoel AC, Nielsen VG, Pretorius E. Viscoelasticity and Ultrastructure in Coagulation and Inflammation: Two Diverse Techniques, One Conclusion. Inflammation 2015; 38:1707-26. [PMID: 25772112 DOI: 10.1007/s10753-015-0148-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The process of blood clotting has been studied for centuries. A synopsis of current knowledge pertaining to haemostasis and the blood components, including platelets and fibrin networks which are closely involved in coagulation, are discussed. Special emphasis is placed on tissue factor (TF), calcium and thrombin since these components have been implicated in both the coagulation process and inflammation. Analysis of platelets and fibrin morphology indicate that calcium, tissue factor and thrombin at concentrations used during viscoelastic analysis (with thromboelastography or TEG) bring about alterations in platelet and fibrin network ultrastructure, which is similar to that seen in inflammation. Scanning electron microscopy indicated that, when investigating platelet structure in disease, addition of TF, calcium or thrombin will mask disease-induced alterations associated with platelet activation. Therefore, washed platelets without any additives is preferred for morphological analysis. Furthermore, morphological and viscoelastic analysis confirmed that thrombin activation is the preferred method of fibrin activation when investigating fibrin network ultrastructure.
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Affiliation(s)
- Albe C Swanepoel
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Private Bag x323, Arcadia, 0007, South Africa,
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21
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Povsic TJ, Vavalle JP, Alexander JH, Aberle LH, Zelenkofske SL, Becker RC, Buller CE, Cohen MG, Cornel JH, Kasprzak JD, Montalescot G, Fail PS, Sarembock IJ, Mehran R. Use of the REG1 anticoagulation system in patients with acute coronary syndromes undergoing percutaneous coronary intervention: results from the phase II RADAR-PCI study. EUROINTERVENTION 2015; 10:431-8. [PMID: 24929350 DOI: 10.4244/eijy14m06_01] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIMS We sought to determine the feasibility of conducting percutaneous coronary intervention (PCI) in high-risk acute coronary syndrome (ACS) patients utilising the REG1 system consisting of pegnivacogin, an aptameric factor IXa inhibitor, and its controlling agent anivamersen. METHODS AND RESULTS In RADAR, ACS patients were randomised to pegnivacogin 1 mg/kg with 25%, 50%, 75%, or 100% anivamersen reversal or unfractionated heparin. Of the 640 patients randomised, 388 (61%) underwent PCI. Major modified ACUITY 30-day bleeding rates were 18% (25% reversal), 12% (50% reversal), 9% (75% reversal), and 7% (100% reversal), compared with 11% with heparin. The corresponding total bleeding rates were 68%, 39%, 35%, 34%, and 38% (heparin). Ischaemic events were less frequent in those receiving pegnivacogin versus heparin (4.4% vs. 7.3%, p=0.3). Thirty-day urgent TVR (1.1% vs. 0.9%, p=1.0), myocardial infarction (4.0% vs. 6.4%, p=0.3), and angiographic complication (11.2% and 10.8%, p=0.9) rates were similar with pegnivacogin and heparin. There were no incidences of clot formation on guidewires or catheters. CONCLUSIONS High-level factor IXa inhibition in ACS patients undergoing PCI, with at least 50% reversal, has a favourable bleeding profile and appears effective at suppressing ischaemic events and thrombotic complications. Larger phase trials in PCI are warranted. CLINICAL TRIALS REGISTRATION ClinicalTrials.gov NCT00932100.
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Affiliation(s)
- Thomas J Povsic
- Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA
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Personalized antiplatelet therapy with P2Y12 receptor inhibitors: benefits and pitfalls. ADVANCES IN INTERVENTIONAL CARDIOLOGY 2015; 11:259-80. [PMID: 26677375 PMCID: PMC4679793 DOI: 10.5114/pwki.2015.55596] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 11/05/2015] [Accepted: 11/05/2015] [Indexed: 02/07/2023] Open
Abstract
Antiplatelet therapy with P2Y12 receptor inhibitors has become the cornerstone of medical treatment in patients with acute coronary syndrome, after percutaneous coronary intervention and in secondary prevention of atherothrombotic events. Clopidogrel used to be the most broadly prescribed P2Y12 receptor inhibitor with undisputable benefits especially in combination with aspirin, but a considerable number of clopidogrel-treated patients experience adverse thrombotic events in whom insufficient P2Y12-inhibition and a consequential high on-treatment platelet reactivity is a common finding. This clinically relevant limitation of clopidogrel has driven the increased use of new antiplatelet agents. Prasugrel (a third generation thienopyridine) and ticagrelor (a cyclopentyl-triazolo-pyrimidine) feature more potent and predictable P2Y12-inhibition compared to clopidogrel, which translates into improved ischemic outcomes. However, excessive platelet inhibition and consequential low on-treatment platelet reactivity comes at the price of increased risk of major bleeding. The majority of randomized clinical trials failed to demonstrate improved clinical outcomes with platelet function testing and tailored antiplatelet therapy, but results of all recent trials of potent antiplatelets and prolonged antiplatelet durations point towards a need for individualized antiplatelet approach in order to decrease thrombotic events without increasing bleeding. This review focuses on potential strategies for personalizing antiplatelet treatment.
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23
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Whitfield P, Williams A, Nokes T. Managing coagulopathy and thromboprophylaxis in the neurosurgical patient. ADVANCES IN CLINICAL NEUROSCIENCE & REHABILITATION 2015. [DOI: 10.47795/stkk4952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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25
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Majumder R, Koklic T, Sengupta T, Cole D, Chattopadhyay R, Biswas S, Monroe D, Lentz BR. Soluble phosphatidylserine binds to two sites on human factor IXa in a Ca2+ dependent fashion to specifically regulate structure and activity. PLoS One 2014; 9:e100006. [PMID: 24979705 PMCID: PMC4076177 DOI: 10.1371/journal.pone.0100006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 05/20/2014] [Indexed: 11/23/2022] Open
Abstract
Clinical studies have demonstrated a correlation between elevated levels of FIX and the risk of coronary heart disease, while reduced plasma FIX causes hemophilia B. FIXa interacts with FVIIIa in the presence of Ca2+ and phosphatidylserine (PS)-containing membranes to form a factor X-activating complex (Xase) that is key to propagation of the initiated blood coagulation process in human. We test the hypothesis that PS in these membranes up-regulates the catalytic activity of this essential enzyme. We used a soluble form of phosphatidylserine, 1, 2-dicaproyl-sn-glycero-3-phospho-L-serine (C6PS), as a tool to do so. C6PS and PS in membranes are reported to regulate the homologous FXa nearly identically. FIXa binds a molecule of C6PS at each of with two sites with such different affinities (∼100-fold) that these appear to be independent. A high affinity C6PS binding site (Kd∼1.4 µM) regulates structure, whereas a low-affinity binding site (Kd∼140 µM) regulates activity. Equilibrium dialysis experiments were analyzed globally with four other data sets (proteolytic and amidolytic activities, intrinsic fluorescence, ellipticity) to unequivocally demonstrate stoichiometries of one for both sites. Michaelis-Menten parameters for FIXa proteolytic activity were the same in the presence of C6PS or PS/PC membranes. We conclude that the PS molecule and not a membrane surface is the key regulator of both factors Xa and IXa. Despite some minor differences in the details of regulation of factors Xa and IXa, the similarities we found suggest that lipid regulation of these two proteases may be similar, a hypothesis that we continue to test.
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Affiliation(s)
- Rinku Majumder
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
| | - Tilen Koklic
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Tanusree Sengupta
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Daud Cole
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Rima Chattopadhyay
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Subir Biswas
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Dougald Monroe
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Barry R. Lentz
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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Ataullakhanov FI, Dashkevich NM, Negrier C, Panteleev MA. Factor XI and traveling waves: the key to understanding coagulation in hemophilia? Expert Rev Hematol 2014; 6:111-3. [DOI: 10.1586/ehm.13.12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Hoffman M, Cichon LJH. Practical coagulation for the blood banker. Transfusion 2013; 53:1594-602. [PMID: 23560738 DOI: 10.1111/trf.12201] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 02/22/2013] [Accepted: 02/25/2013] [Indexed: 12/29/2022]
Affiliation(s)
- Maureane Hoffman
- Department of Pathology, Duke University Medical Center and Durham Veterans Affairs Medical Center, Durham, NC, USA.
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28
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Golder M, Mewburn J, Lillicrap D. In vitro and in vivo evaluation of the effect of elevated factor VIII on the thrombogenic process. Thromb Haemost 2012. [PMID: 23178924 DOI: 10.1160/th12-05-0316] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Factor VIII (FVIII), a procoagulant cofactor, plays a crucial role in the intrinsic coagulation cascade. A causal association between elevated FVIII levels and venous thrombosis incidence has been established; no such association has been confirmed with arterial thrombosis. The independent role of elevated FVIII levels in arteriolar thrombosis was evaluated in a mouse model to determine the thrombogenic potential of elevated levels of FVIII. The in vitro thrombogenic effect of elevated FVIII levels was examined using thrombin-antithrombin (TAT) complex generation and thromboelastography (TEG) assays. The thrombogenic potential of acute and extended elevation of circulating FVIII levels was assessed using ferric chloride induced injury of the cremaster arterioles. The rate of TAT complex formation, and the final concentration of TAT complexes, significantly increased as FVIII levels were elevated from 100% to 400% FVIII activity. TEG analysis of fibrin and clot formation showed that as FVIII levels were elevated, the time to initial fibrin formation decreased and the rate of fibrin formation increased. The acute elevation of circulating FVIII to 400% FVIII activity resulted in significantly decreased times to vessel occlusion. Prolonged elevation of FVIII activity did not significantly affect time to vessel occlusion. In conclusion, acute elevations in FVIII levels result in a non-linear thrombogenic effect, with non-significant increases in thrombogenic risk within the physiological range (FVIII levels up to 200%). Prolonged elevation of plasma FVIII did not further increase the thrombogenic potential of elevated FVIII levels.
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Affiliation(s)
- M Golder
- Department of Pathology and Molecular Medicine, 201 Richardson Laboratory, Queen's University, Kingston, Ontario, K7L 3N6 Canada
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Abstract
Injury-induced bleeding is stopped by a hemostatic plug formation that is controlled by a complex nonlinear and spatially heterogeneous biochemical network of proteolytic enzymes called blood coagulation. We studied spatial dynamics of thrombin, the central enzyme of this network, by developing a fluorogenic substrate-based method for time- and space-resolved imaging of thrombin enzymatic activity. Clotting stimulation by immobilized tissue factor induced localized thrombin activity impulse that propagated in space and possessed all characteristic traits of a traveling excitation wave: constant spatial velocity, constant amplitude, and insensitivity to the initial stimulation once it exceeded activation threshold. The parameters of this traveling wave were controlled by the availability of phospholipids or platelets, and the wave did not form in plasmas from hemophilia A or C patients who lack factors VIII and XI, which are mediators of the two principal positive feedbacks of coagulation. Stimulation of the negative feedback of the protein C pathway with thrombomodulin produced nonstationary patterns of wave formation followed by deceleration and annihilation. This indicates that blood can function as an excitable medium that conducts traveling waves of coagulation.
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Povsic TJ, Vavalle JP, Aberle LH, Kasprzak JD, Cohen MG, Mehran R, Bode C, Buller CE, Montalescot G, Cornel JH, Rynkiewicz A, Ring ME, Zeymer U, Natarajan M, Delarche N, Zelenkofske SL, Becker RC, Alexander JH. A Phase 2, randomized, partially blinded, active-controlled study assessing the efficacy and safety of variable anticoagulation reversal using the REG1 system in patients with acute coronary syndromes: results of the RADAR trial. Eur Heart J 2012; 34:2481-9. [PMID: 22859796 DOI: 10.1093/eurheartj/ehs232] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AIMS We sought to determine the degree of anticoagulation reversal required to mitigate bleeding, and assess the feasibility of using pegnivacogin to prevent ischaemic events in acute coronary syndrome (ACS) patients managed with an early invasive approach. REG1 consists of pegnivacogin, an RNA aptamer selective factor IXa inhibitor, and its complementary controlling agent, anivamersen. REG1 has not been studied in invasively managed patients with ACS nor has an optimal level of reversal allowing safe sheath removal been defined. METHODS AND RESULTS Non-ST-elevation ACS patients (n = 640) with planned early cardiac catheterization via femoral access were randomized 2:1:1:2:2 to pegnivacogin with 25, 50, 75, or 100% anivamersen reversal or heparin. The primary endpoint was total ACUITY bleeding through 30 days. Secondary endpoints included major bleeding and the composite of death, myocardial infarction, urgent target vessel revascularization, or recurrent ischaemia. Enrolment in the 25% reversal arm was suspended after 41 patients. Enrolment was stopped after three patients experienced allergic-like reactions. Bleeding occurred in 65, 34, 35, 30, and 31% of REG1 patients with 25, 50, 75, and 100% reversal and heparin. Major bleeding occurred in 20, 11, 8, 7, and 10% of patients. Ischaemic events occurred in 3.0 and 5.7% of REG1 and heparin patients, respectively. CONCLUSION At least 50% reversal is required to allow safe sheath removal after cardiac catheterization. REG1 appears a safe strategy to anticoagulate ACS patients managed invasively and warrants further investigation in adequately powered clinical trials of patients who require short-term high-intensity anticoagulation.
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Affiliation(s)
- Thomas J Povsic
- Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA
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Weigel KJ, Rues L, Doyle EJ, Buchheit CL, Wood JG, Gallagher RJ, Kelly LE, Radel JD, Bradley KA, LeVine SM. Rapid vascular responses to anthrax lethal toxin in mice containing a segment of chromosome 11 from the CAST/Ei strain on a C57BL/6 genetic background. PLoS One 2012; 7:e40126. [PMID: 22792226 PMCID: PMC3390349 DOI: 10.1371/journal.pone.0040126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 06/01/2012] [Indexed: 11/29/2022] Open
Abstract
Host allelic variation controls the response to B. anthracis and the disease course of anthrax. Mouse strains with macrophages that are responsive to anthrax lethal toxin (LT) show resistance to infection while mouse strains with LT non-responsive macrophages succumb more readily. B6.CAST.11M mice have a region of chromosome 11 from the CAST/Ei strain (a LT responsive strain) introgressed onto a LT non-responsive C57BL/6J genetic background. Previously, B6.CAST.11M mice were found to exhibit a rapid inflammatory reaction to LT termed the early response phenotype (ERP), and displayed greater resistance to B. anthracis infection compared to C57BL/6J mice. Several ERP features (e.g., bloat, hypothermia, labored breathing, dilated pinnae vessels) suggested vascular involvement. To test this, Evan’s blue was used to assess vessel leakage and intravital microscopy was used to monitor microvascular blood flow. Increased vascular leakage was observed in lungs of B6.CAST.11M mice compared to C57BL/6J mice 1 hour after systemic administration of LT. Capillary blood flow was reduced in the small intestine mesentery without concomitant leukocyte emigration following systemic or topical application of LT, the latter suggesting a localized tissue mechanism in this response. Since LT activates the Nlrp1b inflammasome in B6.CAST.11M mice, the roles of inflammasome products, IL-1β and IL-18, were examined. Topical application to the mesentery of IL-1β but not IL-18 revealed pronounced slowing of blood flow in B6.CAST.11M mice that was not present in C57BL/6J mice. A neutralizing anti-IL-1β antibody suppressed the slowing of blood flow induced by LT, indicating a role for IL-1β in the response. Besides allelic differences controlling Nlrp1b inflammasome activation by LT observed previously, evidence presented here suggests that an additional genetic determinant(s) could regulate the vascular response to IL-1β. These results demonstrate that vessel leakage and alterations to blood flow are part of the rapid response in mice resistant to B. anthracis infection.
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Affiliation(s)
- Kelsey J. Weigel
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Rockhurst University, Kansas City, Missouri, United States of America
| | - Laura Rues
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Rockhurst University, Kansas City, Missouri, United States of America
| | - Edward J. Doyle
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Rockhurst University, Kansas City, Missouri, United States of America
| | - Cassandra L. Buchheit
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Rockhurst University, Kansas City, Missouri, United States of America
| | - John G. Wood
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Department of Surgery, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Ryan J. Gallagher
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Laura E. Kelly
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- Rockhurst University, Kansas City, Missouri, United States of America
| | - Jeffrey D. Radel
- Department of Occupational Therapy Education, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Kenneth A. Bradley
- Department of Microbiology, Immunology & Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Steven M. LeVine
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- * E-mail:
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Sølbeck S, Ostrowski SR, Johansson PI. A review of the clinical utility of INR to monitor and guide administration of prothrombin complex concentrate to orally anticoagulated patients. Thromb J 2012; 10:5. [PMID: 22546056 PMCID: PMC3413545 DOI: 10.1186/1477-9560-10-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 04/30/2012] [Indexed: 01/21/2023] Open
Abstract
Background and objectives The number of patients treated with oral anticoagulation (OAC) is increasing and these patients are monitored by International Normalized Ratio (INR). Bleeding complications are common and we speculate if this is related to the limitation of INR only reflecting the initiation steps of the haemostatic process. The objective of the present review was to reassess the evidence for using INR as a tool to guide administration of prothrombin complex concentrates (PCC) to OAC patients. A Medline and Cochrane database search was conducted using the following keywords: prothrombin complex concentrate, reversal of oral anticoagulation and international normalized ratio (INR). Thirty-three articles were contracted and a total of ten studies were eligible after applying inclusion and exclusion criteria encompassing only 339 patients. No consensus regarding optimal target INR value to aim for when reversing OAC was found. In three of the studies it was reported that patients reaching their target INR continued to bleed, whereas three studies reviewed reported good haemostatic response also in patients that did not reach their target INR. The present review found limited evidence for the usefulness of INR as a tool to monitor and guide reversal of OAC induced coagulopathy in patients with PCC, which is expected given that it is a plasma-based assay only reflecting a limited part of the haemostatic process.
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Affiliation(s)
- Sacha Sølbeck
- Section for Transfusion Medicine, Capital Region Blood Bank, Rigshospitalet University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
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Positive feedback loops for factor V and factor VII activation supply sensitivity to local surface tissue factor density during blood coagulation. Biophys J 2012; 101:1816-24. [PMID: 22004734 DOI: 10.1016/j.bpj.2011.08.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 07/12/2011] [Accepted: 08/09/2011] [Indexed: 11/22/2022] Open
Abstract
Blood coagulation is triggered not only by surface tissue factor (TF) density but also by surface TF distribution. We investigated recognition of surface TF distribution patterns during blood coagulation and identified the underlying molecular mechanisms. For these investigations, we employed 1), an in vitro reaction-diffusion experimental model of coagulation; and 2), numerical simulations using a mathematical model of coagulation in a three-dimensional space. When TF was uniformly immobilized over the activating surface, the clotting initiation time in normal plasma increased from 4 min to >120 min, with a decrease in TF density from 100 to 0.7 pmol/m(2). In contrast, surface-immobilized fibroblasts initiated clotting within 3-7 min, independently of fibroblast quantity and despite a change in average surface TF density from 0.5 to 130 pmol/m(2). Experiments using factor V-, VII-, and VIII-deficient plasma and computer simulations demonstrated that different responses to these two TF distributions are caused by two positive feedback loops in the blood coagulation network: activation of the TF-VII complex by factor Xa, and activation of factor V by thrombin. This finding suggests a new role for these reactions: to supply sensitivity to local TF density during blood coagulation.
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Povsic TJ, Wargin WA, Alexander JH, Krasnow J, Krolick M, Cohen MG, Mehran R, Buller CE, Bode C, Zelenkofske SL, Rusconi CP, Becker RC. Pegnivacogin results in near complete FIX inhibition in acute coronary syndrome patients: RADAR pharmacokinetic and pharmacodynamic substudy. Eur Heart J 2011; 32:2412-9. [PMID: 21724623 DOI: 10.1093/eurheartj/ehr179] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS Establishing factor IX inhibition in patients with acute coronary syndrome/non-ST-elevation myocardial infarction (ACS/NSTEMI), a setting characterized by increased factor IX activity, is critical to investigate the REG1 system in this target population. The REG1 system (Regado Biosciences, Basking Ridge, NJ) consists of pegnivacogin (RB006), an RNA aptamer that directly inhibits factor IXa, and anivamersen (RB007), its complementary control agent. METHODS AND RESULTS RADAR is a Phase 2b study investigating the use of pegnivacogin in patients (n = 800) with ACS undergoing planned early cardiac catheterization. To validate dose selection and stability of anticoagulation throughout the time of cardiac catheterization at an early stage of the clinical trial, 33 patients, 22 of whom had not received recent prior heparin, underwent thorough pharmacokinetic and pharmacodynamic assessment. Fold prolongation of activated partial thromboplastin time (aPTT) was used to impute factor IX inhibition. Pegnivacogin 1 mg/kg rapidly achieved a high pegnivacogin plasma concentration (26.1 ± 4.6 µg/mL), prolonged the aPTT (mean aPTT 93.0 ± 9.5 s), and approached near complete factor IX inhibition (mean fold increase from baseline 2.9 ± 0.3). These levels remained stable from the time of drug administration through completion of the catheterization. CONCLUSION Pegnivacogin administered at a weight-adjusted dose of 1 mg/kg consistently achieves a high level of factor IX activity inhibition among patients with ACS and provides stable anticoagulation during cardiac catheterization. These findings support the dose of pegnivacogin selected for the RADAR study.
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Affiliation(s)
- Thomas J Povsic
- Department of Medicine, Division of Cardiology, Duke Clinical Research Institute, Duke University Medical Center, Box 103208, Durham, NC 27710, USA.
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A randomized, partially blinded, multicenter, active-controlled, dose-ranging study assessing the safety, efficacy, and pharmacodynamics of the REG1 anticoagulation system in patients with acute coronary syndromes: design and rationale of the RADAR Phase IIb trial. Am Heart J 2011; 161:261-268.e1-2. [PMID: 21315207 DOI: 10.1016/j.ahj.2010.10.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 10/15/2010] [Indexed: 11/23/2022]
Abstract
Anticoagulants are the cornerstone of current acute coronary syndrome (ACS) therapy; however, anticoagulation regimens that aggressively reduce ischemic events are almost uniformly associated with more bleeding. REG1, an anticoagulation system, consists of RB006 (pegnivacogin), an RNA oligonucleotide factor IXa inhibitor, and RB007 (anivamersen), its complementary controlling agent. Phase I and IIa studies defined predictable relationships between doses of RB006, RB007, and degree of antifactor IX activity. The efficacy and safety of REG1 for the treatment of patients with ACS managed invasively and the safety of reversing RB006 with RB007 after cardiac catheterization are unknown. Randomized, partially-blinded, multicenter, active-controlled, dose-ranging study assessing the safety, efficacy, and pharmacodynamics of the REG1 anticoagulation system compared to unfractionated heparin or low molecular heparin in subjects with acute coronary syndrome (RADAR) is designed to assess both the efficacy of the anticoagulant RB006 and the safety of a range of levels of RB006 reversal with RB007. The objectives of RADAR are (1) to determine the safety of a range of levels of RB006 reversal with RB007 after catheterization, (2) to confirm whether a dose of 1 mg/kg RB006 results in near-complete inhibition of factor IXa in patients with ACS, and (3) to assess the efficacy of RB006 as an anticoagulant in patients with ACS undergoing percutaneous coronary intervention.
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Povsic TJ, Sullenger BA, Zelenkofske SL, Rusconi CP, Becker RC. Translating nucleic acid aptamers to antithrombotic drugs in cardiovascular medicine. J Cardiovasc Transl Res 2010; 3:704-16. [PMID: 21080135 DOI: 10.1007/s12265-010-9230-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 10/07/2010] [Indexed: 11/29/2022]
Abstract
Nucleic acid aptamers offer several distinct advantages for the selective inhibition of protein targets within the coagulation cascade. A highly attractive feature of aptamers as antithrombotics is their ability to encode for complementary "controlling agents" which selectively bind to and neutralize their active counterparts via Watson-Crick base pairing or, in a less selective and clinically characterized manner, cationic polymers that can counteract the activity of an aptamer or free/protein-complexed nucleic acid. The former property allows aptamer-based antithrombotic therapies to be administered with a goal of selective, high intensity target inhibition, knowing that rapid drug reversal is readily available. In addition, by purposefully varying the ratio of active agent to a specific controlling agent administered, the intensity of antithrombotic therapy can be regulated with precision according to patient needs and the accompanying clinical conditions. REG1, currently undergoing phase 2B clinical investigation, consists of an RNA aptamer (RB006; pegnivacogin) which targets factor IXa and its complementary controlling agent (RB007; anivamersen). Aptamers directed against other serine coagulation proteases, some with and some without parallel controlling agents, have been designed. Aptamers directed against platelet surface membrane receptor targets are in preclinical development. The following review offers a contemporary summary of nucleic acid aptamers as a translatable platform for regulatable antithrombotic drugs expanding the paradigm of patient- and disease-specific treatment in clinical practice.
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Affiliation(s)
- Thomas J Povsic
- Division of Cardiology, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
The use of warfarin has a well-known bleeding risk. Recombinant activated factor VII (rFVIIa) is a non–plasma-derived, rapid-acting, and rapidly infused potential treatment. This randomized, single-center, placebo-controlled, double-blinded, dose-escalation, exploratory phase 1 trial assessed safety and effects of rFVIIa in reversing warfarin-induced changes in bleeding and coagulation parameters, using a punch biopsy–induced bleeding model in healthy subjects. The effects of warfarin (experiment 1) and rFVIIa (5-80 μg/kg; experiment 2) were evaluated. Outcomes were bleeding duration, blood loss, coagulation parameters, and safety. Warfarin treatment significantly increased bleeding duration and blood loss from pretreatment (experiment 1, 12 subjects). However, these parameters after rFVIIa treatment were not significantly different from placebo (experiment 2, 85 subjects). Mean activated partial thromboplastin time, prothrombin time, and international normalized ratio were reduced from warfarin-elevated levels. rFVIIa (80 μg/kg) significantly reversed warfarin effects on all thromboelastography parameters, compared with placebo (P < .05), and returned the thrombin generation speed to baseline. There were no thromboembolic or serious adverse events. In this exploratory trial, the reversal of warfarin effects was observed in the thromboelastography, thrombin generation, and clotting assays. However, this reversal did not translate to improvements in the bleeding model parameters evaluated in the punch biopsy model. Trial registration is exempt (phase 1).
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Panteleev MA, Balandina AN, Lipets EN, Ovanesov MV, Ataullakhanov FI. Task-oriented modular decomposition of biological networks: trigger mechanism in blood coagulation. Biophys J 2010; 98:1751-61. [PMID: 20441738 DOI: 10.1016/j.bpj.2010.01.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 01/10/2010] [Accepted: 01/15/2010] [Indexed: 11/16/2022] Open
Abstract
Analysis of complex time-dependent biological networks is an important challenge in the current postgenomic era. We propose a middle-out approach for decomposition and analysis of complex time-dependent biological networks based on: 1), creation of a detailed mechanism-driven mathematical model of the network; 2), network response decomposition into several physiologically relevant subtasks; and 3), subsequent decomposition of the model, with the help of task-oriented necessity and sensitivity analysis into several modules that each control a single specific subtask, which is followed by further simplification employing temporal hierarchy reduction. The technique is tested and illustrated by studying blood coagulation. Five subtasks (threshold, triggering, control by blood flow velocity, spatial propagation, and localization), together with responsible modules, can be identified for the coagulation network. We show that the task of coagulation triggering is completely regulated by a two-step pathway containing a single positive feedback of factor V activation by thrombin. These theoretical predictions are experimentally confirmed by studies of fibrin generation in normal, factor V-, and factor VIII-deficient plasmas. The function of the factor V-dependent feedback is to minimize temporal and parametrical intervals of fibrin clot instability. We speculate that this pathway serves to lessen possibility of fibrin clot disruption by flow and subsequent thromboembolism.
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Affiliation(s)
- Mikhail A Panteleev
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Moscow, Russia.
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Esch JSA, Jurk K, Knoefel WT, Roeder G, Voss H, Tustas RY, Schmelzle M, Krieg A, Eisenberger CF, Topp S, Rogiers X, Fischer L, Aken HV, Kehrel BE. Platelet activation and increased tissue factor expression on monocytes in reperfusion injury following orthotopic liver transplantation. Platelets 2010; 21:348-59. [DOI: 10.3109/09537101003739897] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Catheter thrombosis and percutaneous coronary intervention: fundamental perspectives on blood, artificial surfaces and antithrombotic drugs. J Thromb Thrombolysis 2009; 28:366-80. [PMID: 19597766 DOI: 10.1007/s11239-009-0375-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Recent reports of catheter thrombosis among patients undergoing percutaneous coronary intervention (PCI) have had a significant impact on the development of new antithrombotic therapies. The overall incidence of this complication is unknown, mainly because of underreporting in contemporary clinical trials of coronary intervention. The etiology and pathophysiology of catheter thrombosis is also poorly understood. Introduction of a catheter or guidewire may not provoke the intense thrombotic response that follows angioplasty or stenting, but factors such as catheter materials and device size, equipment surface properties, flow conditions, procedural time and complexity, as well as the antiplatelet and anticoagulant drugs administered during the procedure influence the likelihood, rate and clinical impact of thrombosis. The crucial role of cellular interactions involving tissue-factor bearing cells and platelets in the process of thrombosis also needs to be critically explored when considering blood contact with an exogenous material. Focusing on the inherently prothrombotic environment of percutaneous coronary intervention, we review the physiologic underpinnings of catheter and guidewire thrombosis, and explore the effect of antithrombotic drugs at the interface between blood and material surfaces. We also propose a clinical classification for the diagnosis and investigation of catheter thrombosis in clinical trials of anticoagulant therapy and PCI.
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Becker RC, Oney S, Becker KCD, Sullenger B. Antidote-controlled antithrombotic therapy targeting factor IXa and von Willebrand factor. Ann N Y Acad Sci 2009; 1175:61-70. [PMID: 19796078 DOI: 10.1111/j.1749-6632.2009.05017.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thrombotic disorders and their common clinical phenotypes of acute myocardial infarction, ischemic stroke, and venous thromboembolism are the proximate cause of substantial morbidity, mortality, and health care expenditures worldwide. Accordingly, therapies designed to attenuate thrombus initiation and propagation, reflecting integrated platelet-mediated and coagulation protease-mediated events, respectively, represent a standard of care. Unfortunately, there are numerous inherent limitations of existing therapies that include target nonselectivity, variable onset and offset of pharmacodynamic effects, a narrow efficacy-safety profile, and the absence of a safe and reliable platform for either accurate titration, based on existing patient-specific, disease-specific, and clinical conditions, or active reversibility. Herein, we summarize our experience with oligonucleotide antithrombotic agents and their complementary antidotes, targeting the platelet adhesive protein von Willebrand factor and the pivotal coagulation protease factor IXa.
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Affiliation(s)
- Richard C Becker
- Division of Hematology , Duke University School of Medicine, Duke Clinical Research Institute, Biosignatures Program, Durham, North Carolina 27701, USA.
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Abstract
BACKGROUND Over the past century, a series of models have been put forth to explain the coagulation mechanism. The coagulation cascade/waterfall model has gained the most widespread acceptance. This model, however, has problems when it is used in different clinical scenarios. A more recently proposed cell-based model better describes the coagulation process in vivo and provides oral health care professionals (OHCPs) with a better understanding of the clinical implications of providing dental care to patients with potentially increased bleeding tendencies. METHODS The authors conducted a literature search using the PubMed database. They searched for key words including "coagulation," "hemostasis," "bleeding," "coagulation factors," "models," "prothrombin time," "activated partial thromboplastin time," "international normalized ratio," "anticoagulation therapy" and "hemophilia" separately and in combination. CONCLUSIONS The coagulation cascade/waterfall model is insufficient to explain coagulation in vivo, predict a patient's bleeding tendency, or correlate clinical outcomes with specific laboratory screening tests such as prothrombin time, activated partial thromboplastin time and international normalized ratio. However, the cell-based model of coagulation that reflects the in vivo process of coagulation provides insight into the clinical ramifications of treating dental patients with specific coagulation factor deficiencies. CLINICAL IMPLICATIONS Understanding the in vivo coagulation process will help OHCPs better predict a patient's bleeding tendency. In addition, applying the theoretical concept of the cell-based model of coagulation to commonly used laboratory screening tests for coagulation and bleeding will result in safer and more appropriate dental care.
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Abstract
Antiphospholipid (aPL) antibodies are clinically important acquired risk factors for thrombosis and pregnancy loss and are thought to have a direct prothrombotic effect in vivo. Data suggest that a major mechanism by which aPL antibodies contribute to thrombophilia is the upregulation of tissue factor (TF) (CD142) on blood cells and vascular endothelium. TF is the physiological trigger of normal blood coagulation and thrombosis in many hypercoagulable conditions. This article reviews the physiology of TF, the molecular regulation of TF expression and the effects of aPL antibodies on intravascular TF regulation and expression. Inhibition of TF and the pathways by which aPL antibodies induce TF expression are potentially attractive therapeutic targets in the antiphospholipid syndrome.
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Affiliation(s)
- A V Kinev
- Department of Medicine and Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7280, USA
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Wolberg AS, Campbell RA. Thrombin generation, fibrin clot formation and hemostasis. Transfus Apher Sci 2008; 38:15-23. [PMID: 18282807 DOI: 10.1016/j.transci.2007.12.005] [Citation(s) in RCA: 218] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hemostatic clot formation entails thrombin-mediated cleavage of fibrinogen to fibrin. Previous in vitro studies have shown that the thrombin concentration present during clot formation dictates the ultimate fibrin structure. In most prior studies of fibrin structure, clotting was initiated by adding thrombin to a solution of fibrinogen; however, clot formation in vivo occurs in an environment in which the concentration of free thrombin changes over the reaction course. These changes depend on local cellular properties and available concentrations of pro- and anti-coagulants. Recent studies suggest that abnormal thrombin generation patterns produce abnormally structured clots that are associated with an increased risk of bleeding or thrombosis. Further studies of fibrin formation during in situ thrombin generation are needed to understand fibrin clot formation in vivo.
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Affiliation(s)
- Alisa S Wolberg
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, 815 Brinkhous-Bullitt Building, CB #7525, Chapel Hill, NC 27599-7525, USA.
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Mayo A, Martinowitz U, Kluger Y. Coagulopathy in the Critically Injured Patient. Intensive Care Med 2007. [DOI: 10.1007/0-387-35096-9_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Graff J, Skarke C, Klinkhardt U, Watzer B, Harder S, Seyberth H, Geisslinger G, Nüsing RM. Effects of selective COX-2 inhibition on prostanoids and platelet physiology in young healthy volunteers. J Thromb Haemost 2007; 5:2376-85. [PMID: 17916229 DOI: 10.1111/j.1538-7836.2007.02782.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Selective inhibitors of cyclooxygenase-2 (COX-2) called coxibs, are effective anti-inflammatory and analgesic drugs. Recently, these drugs were associated with an increased risk for myocardial infarction and atherothrombotic events. The hypothesis of thromboxane-prostacyclin imbalance has been preferred to explain these unwanted effects. METHODS We studied the effects of 14 days intake of rofecoxib (25 mg q.d.), celecoxib (200 mg b.i.d.), naproxen (500 mg b.i.d.) and placebo in a randomized, blinded, placebo-controlled study in young healthy volunteers (median age 25-30 years, each group n = 10). We assessed prostanoid metabolite excretion (PGE-M, TXB(2), 6-keto-PGF(1alpha), 11-dehydro-TXB(2), 2,3-dinor-TXB(2), and dinor-6-keto-PGF(1alpha)), the expression of platelet activation markers (CD62P, PAC-1, fibrinogen), platelet-leukocyte formation, the endogenous thrombin potential, platelet cAMP content and plasma thrombomodulin level. RESULTS Naproxen suppressed biosynthesis of PGE-M, prostacyclin metabolites and thromboxane metabolites and thrombomodulin levels. In contrast, both coxibs had an inhibitory effect only on PGE-M, 6-keto-PGF(1alpha), and on dinor-6-keto-PGF(1alpha), whereas TXB(2), 2,3-dinor-TXB(2) and 11-dehydro-TXB(2) excretion were unaffected. None of the coxibs exerted significant effects on the expression of platelet activation markers, cAMP generation, platelet-leukocyte formation, or on thrombomodulin plasma levels. Interestingly, platelet TXB(2) release during aggregation was enhanced after coxib treatment following arachidonic acid or collagen stimulation. CONCLUSION In young healthy volunteers coxibs inhibit systemic PGE(2) and PGI(2) synthesis. Platelet function and expression of platelet aggregation markers are not affected; however, coxibs can stimulate TXB(2) release from activated platelets. Combined decrease in vasodilatory PGE(2) and PGI(2) together with increased TXA(2) in proaggregatory conditions may contribute to coxib side effects.
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Affiliation(s)
- J Graff
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern Kai 7, Frankfurt am Main, Germany
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Abstract
The authors propose that hemostasis occurs in a stepwise process, regulated by cellular components in vivo. The effectiveness of hemostasis in vivo depends not only on the procoagulant reactions but also on the fibrinolytic process. Causes of coagulopathic bleeding include consumption of coagulation factors and platelets, excessive fibrinolysis, hypothermia, and acidosis. Generation of the right amount of thrombin during the coagulation process not only may be essential for effective hemostasis but also may set the stage for effective wound healing.
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Affiliation(s)
- Maureane Hoffman
- Pathology and Laboratory Medicine Service (113), Durham Veterans Affairs Medical Center, 508 Fulton Street, Durham, NC 27705, USA.
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