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Mariño-Ocampo N, Rodríguez DF, Guerra Díaz D, Zúñiga-Núñez D, Duarte Y, Fuentealba D, Zacconi FC. Direct Oral FXa Inhibitors Binding to Human Serum Albumin: Spectroscopic, Calorimetric, and Computational Studies. Int J Mol Sci 2023; 24:ijms24054900. [PMID: 36902328 PMCID: PMC10002493 DOI: 10.3390/ijms24054900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/26/2023] [Accepted: 03/01/2023] [Indexed: 03/06/2023] Open
Abstract
Direct FXa inhibitors are an important class of bioactive molecules (rivaroxaban, apixaban, edoxaban, and betrixaban) applied for thromboprophylaxis in diverse cardiovascular pathologies. The interaction of active compounds with human serum albumin (HSA), the most abundant protein in blood plasma, is a key research area and provides crucial information about drugs' pharmacokinetics and pharmacodynamic properties. This research focuses on the study of the interactions between HSA and four commercially available direct oral FXa inhibitors, applying methodologies including steady-state and time-resolved fluorescence, isothermal titration calorimetry (ITC), and molecular dynamics. The HSA complexation of FXa inhibitors was found to occur via static quenching, and the complex formation in the ground states affects the fluorescence of HSA, with a moderate binding constant of 104 M-1. However, the ITC studies reported significantly different binding constants (103 M-1) compared with the results obtained through spectrophotometric methods. The suspected binding mode is supported by molecular dynamics simulations, where the predominant interactions were hydrogen bonds and hydrophobic interactions (mainly π-π stacking interactions between the phenyl ring of FXa inhibitors and the indole moiety of Trp214). Finally, the possible implications of the obtained results regarding pathologies such as hypoalbuminemia are briefly discussed.
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Affiliation(s)
- Nory Mariño-Ocampo
- Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
| | - Diego F. Rodríguez
- Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
| | - Daniel Guerra Díaz
- Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
| | - Daniel Zúñiga-Núñez
- Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
| | - Yorley Duarte
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370035, Chile
| | - Denis Fuentealba
- Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
- Correspondence: (D.F.); (F.C.Z.)
| | - Flavia C. Zacconi
- Escuela de Química, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
- Centro de Investigaciones en Nanotecnología y Materiales Avanzados, CIEN-UC, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
- Center for Nanomedicine, Diagnostic & Drug Development (ND3), Universidad de Talca, Talca 3460000, Chile
- Correspondence: (D.F.); (F.C.Z.)
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Østergaard H, Lund J, Greisen PJ, Kjellev S, Henriksen A, Lorenzen N, Johansson E, Røder G, Rasch MG, Johnsen LB, Egebjerg T, Lund S, Rahbek-Nielsen H, Gandhi PS, Lamberth K, Loftager M, Andersen LM, Bonde AC, Stavenuiter F, Madsen DE, Li X, Holm TL, Ley CD, Thygesen P, Zhu H, Zhou R, Thorn K, Yang Z, Hermit MB, Bjelke JR, Hansen BG, Hilden I. A factor VIIIa-mimetic bispecific antibody, Mim8, ameliorates bleeding upon severe vascular challenge in hemophilia A mice. Blood 2021; 138:1258-1268. [PMID: 34077951 PMCID: PMC8499050 DOI: 10.1182/blood.2020010331] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 05/11/2021] [Indexed: 11/29/2022] Open
Abstract
Hemophilia A is a bleeding disorder resulting from deficient factor VIII (FVIII), which normally functions as a cofactor to activated factor IX (FIXa) that facilitates activation of factor X (FX). To mimic this property in a bispecific antibody format, a screening was conducted to identify functional pairs of anti-FIXa and anti-FX antibodies, followed by optimization of functional and biophysical properties. The resulting bispecific antibody (Mim8) assembled efficiently with FIXa and FX on membranes, and supported activation with an apparent equilibrium dissociation constant of 16 nM. Binding affinity with FIXa and FX in solution was much lower, with equilibrium dissociation constant values for FIXa and FX of 2.3 and 1.5 µM, respectively. In addition, the activity of Mim8 was dependent on stimulatory activity contributed by the anti-FIXa arm, which enhanced the proteolytic activity of FIXa by 4 orders of magnitude. In hemophilia A plasma and whole blood, Mim8 normalized thrombin generation and clot formation, with potencies 13 and 18 times higher than a sequence-identical analogue of emicizumab. A similar potency difference was observed in a tail vein transection model in hemophilia A mice, whereas reduction of bleeding in a severe tail-clip model was observed only for Mim8. Furthermore, the pharmacokinetic parameters of Mim8 were investigated and a half-life of 14 days shown in cynomolgus monkeys. In conclusion, Mim8 is an activated FVIII mimetic with a potent and efficacious hemostatic effect based on preclinical data.
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Affiliation(s)
| | | | - Per J Greisen
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | | | - Anette Henriksen
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Nikolai Lorenzen
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Eva Johansson
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Gustav Røder
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Morten G Rasch
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Laust B Johnsen
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Thomas Egebjerg
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Søren Lund
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | | | - Prafull S Gandhi
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Kasper Lamberth
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | | | | | | | | | | | - Xun Li
- Discovery Technology China, Novo Nordisk A/S, Beijing, China
| | | | | | | | - Haisun Zhu
- Discovery Technology China, Novo Nordisk A/S, Beijing, China
| | - Rong Zhou
- Discovery Technology China, Novo Nordisk A/S, Beijing, China
| | | | - Zhiru Yang
- Discovery Technology China, Novo Nordisk A/S, Beijing, China
| | | | - Jais R Bjelke
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
| | - Bjarne G Hansen
- Global Research Technologies, Novo Nordisk A/S, Maaloev, Denmark; and
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Abstract
Direct oral anticoagulants (DOACs) are increasingly used in the treatment and prophylaxis of thromboembolism because of several advantages over vitamin K antagonists, including no need for laboratory monitoring. However, it has become increasingly important in certain clinical scenarios to know either actual DOAC concentration (quantitative) or presence of DOAC (qualitative). These clinical conditions include patients presenting with major bleeding or requiring urgent surgery who may need a reversal or hemostatic agent, extremes of body weight, failed therapy, etc. Prothrombin time and activated partial thromboplastin time are variably affected by factor Xa inhibitors (FXaIs) and direct thrombin inhibitor (DTI), respectively, depending on reagents' sensitivity, and hence, they cannot be relied on confidently. Thrombin time is highly sensitive to very low amounts of DTI; thus, normal value rules out a clinically significant amount. Liquid chromatography mass spectrometry accurately measures DOAC levels but is clinically impractical. Dilute thrombin time and ecarin-based assays using appropriate calibrators/controls provide an accurate DTI level. Anti-Xa assay using corresponding FXaI calibrators/controls provides accurate drug levels. However, these assays are not readily available in the United States compared with some other parts of the world. Heparin assays using anti-Xa activity often have a linear relationship with calibrated FXaI assays, especially at the lower end of on-therapy levels, and they may provide rapid assessment of drug activity for clinical decision making. Currently, there is very limited knowledge of DOAC effect on viscoelastic measurements. Although there is uniformity in expression of DOAC concentrations in nanograms per milliliter, a universal FXaI DOAC assay is urgently needed.
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Affiliation(s)
- Ravi Sarode
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX
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Minami H, Nogami K, Yada K, Ogiwara K, Furukawa S, Soeda T, Kitazawa T, Shima M. Emicizumab, the bispecific antibody to factors IX/IXa and X/Xa, potentiates coagulation function in factor XI-deficient plasma in vitro. J Thromb Haemost 2019; 17:126-137. [PMID: 30444568 DOI: 10.1111/jth.14334] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Indexed: 08/31/2023]
Abstract
Essentials Emicizumab mimics factor (F)VIIIa cofactor function, augments the intrinsic tenase activity. We assessed the emicizumab-driven hemostatic function in FXI-deficient plasmas. Emicizumab improved the coagulation potentials in severe FXI-deficient plasma. Emicizumab may provide a possibility for clinical application in patients with FXI deficiency. SUMMARY: Background Patients with factor (F)XI deficiency commonly present with markedly prolonged activated partial thromboplastin times (APTT), although bleeding phenotypes are heterogeneous. Emicizumab, a bispecific monoclonal antibody to FIX/FIXa and FX/FXa, mimics FVIIIa cofactor function on phospholipid (PL) surfaces. Antibody reactions were designed, therefore, to augment mechanisms during the propagation phase of blood coagulation. Aim To assess emicizumab-driven hemostatic function in FXI-deficient plasmas. Methods and Results Standard ellagic acid (Elg)/PL-based APTTs of different FXI-deficient plasmas (n = 13; FXI activity, < 1 IU dl-1 ) were markedly shortened dose dependently by the presence of emicizumab. To further analyze the effects of emicizumab, clot waveform analysis (CWA) in FXI-deficient plasmas with emicizumab, triggered by tissue factor (TF)/Elg demonstrated improvements in both clot times, reflecting the initiation phase, and coagulation velocity, which represents the propagation phase. Emicizumab also enhanced the TF/Elg-triggered thrombin generation in FXI-deficient plasmas dose-dependently although the degree of enhancement varied in individual cases. Thrombin generation with either FVII-deficient plasma or FIX-deficient plasma treated with anti-FXI antibody showed little or no increase by the co-presence of emicizumab, suggesting that the accelerated thrombin generation in FXI-deficient plasmas by emicizumab should depend on the FIXa-involved coagulation propagation initially triggered by FVIIa/TF. The ex vivo addition of emicizumab to whole blood from three patients with severe FXI deficiency demonstrated modest, dose-dependent improvements in Ca2+ -triggered thromboelastograms (NATEM mode). Conclusion Emicizumab appeared to improve coagulation function in severe FXI-deficient plasma, and might provide possibilities for clinical application in patients with FXI deficiency.
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Affiliation(s)
- H Minami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - K Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - K Yada
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - K Ogiwara
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - S Furukawa
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - T Soeda
- Research Division, Chugai Pharmaceutical Co., Ltd, Kamakura, Japan
| | - T Kitazawa
- Research Division, Chugai Pharmaceutical Co., Ltd, Kamakura, Japan
| | - M Shima
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
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Nogami K, Matsumoto T, Tabuchi Y, Soeda T, Arai N, Kitazawa T, Shima M. Modified clot waveform analysis to measure plasma coagulation potential in the presence of the anti-factor IXa/factor X bispecific antibody emicizumab. J Thromb Haemost 2018; 16:1078-1088. [PMID: 29645406 DOI: 10.1111/jth.14022] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Indexed: 01/10/2023]
Abstract
Essentials The activated partial prothrombin time (aPTT) cannot predict the activity of emicizumab (Emi). Adjusted clot waveform analyses using a prothrombin time (PT)/aPTT initiator were developed. Activity of Emi in the co-presence of factor VIII or bypassing agents was quantified. This assay is useful for assessing coagulation potential in Emi-treated hemophilia A. SUMMARY Background Emicizumab is an anti-activated factor IX/FX bispecific antibody that mimics activated FVIII cofactor function. Emicizumab does not require activation by thrombin, and its effect on shortening the activated partial thromboplastin time (APTT) is much greater than that of FVIII. Therefore, the APTT has limited utility in hemophilia A (HA) patients treated with emicizumab. Aim To evaluate the global coagulation potential of emicizumab. Methods Clot waveform analysis (CWA) with prothrombin time (PT)/APTT mixed reagents was used to define hemostatic monitoring protocols in HA patients. A modified parameter, adjusted-|min1| (Ad|min1|), was developed. Maximum and minimum percentage transmittance were defined as 100% and 0% in the precoagulation and postcoagulation phases, respectively. Ad|min1| was calculated as an index of the maximum velocity of the coagulation process. Results Ad|min1| obtained with mixed-trigger reagent (PT/APTT/buffer, 1 : 15 : 135) in the presence of emicizumab optimally corresponded to the conversion rate estimated in animals; 0.2-0.4 IU dL-1 equivalent FVIII per 1 μg mL-1 emicizumab). Ex vivo addition of emicizumab to HA plasma with or without inhibitors resulted in concentration-dependent increases in Ad|min1|, with some individual variations. The addition of various concentrations of FVIII to HA plasma mixed with emicizumab resulted in dose-dependent increases in Ad|min1|. Similarly, mixtures of activated prothrombin complex concentrate and emicizumab added to HA plasma resulted in dose-dependent increases in Ad|min1|. In contrast, enhanced coagulation potential appeared to be better defined by the clot time than by Ad|min1| in experiments using recombinant activated FVII. Conclusion The PT/APTT reagent-triggered adjusted CWA could provide a useful means of assessing global coagulation potential in emicizumab-treated HA patients, with enhanced activity neither masking nor being masked by FVIII or bypassing agents.
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Affiliation(s)
- K Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - T Matsumoto
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
- Course of Hemophilia Treatment & Pathology, Nara Medical University, Kashihara, Nara, Japan
| | - Y Tabuchi
- Engineering Division, Sysmex Corporation, Kobe, Japan
| | - T Soeda
- Chugai Pharmaceutical Co., Gotenba, Japan
| | - N Arai
- Engineering Division, Sysmex Corporation, Kobe, Japan
| | - T Kitazawa
- Chugai Pharmaceutical Co., Gotenba, Japan
| | - M Shima
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
- Course of Hemophilia Treatment & Pathology, Nara Medical University, Kashihara, Nara, Japan
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Xiong L, Qi Z, Zheng B, Li Z, Wang F, Liu J, Li P. Inhibitory Effect of Triterpenoids from Panax ginseng on Coagulation Factor X. Molecules 2017; 22:molecules22040649. [PMID: 28441767 PMCID: PMC6154706 DOI: 10.3390/molecules22040649] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/09/2017] [Accepted: 04/11/2017] [Indexed: 01/29/2023] Open
Abstract
Enzymes involved in the coagulation process have received great attention as potential targets for the development of oral anti-coagulants. Among these enzymes, coagulation factor Xa (FXa) has remained the center of attention in the last decade. In this study, 16 ginsenosides and two sapogenins were isolated, identified and quantified. To determine the inhibitory potential on FXa, the chromogenic substrates method was used. The assay suggested that compounds 5, 13 and 18 were mainly responsible for the anti-coagulant effect. Furthermore, these three compounds also possessed high thrombin selectivity in the thrombin inhibition assay. Furthermore, Glide XP from Schrödinger was employed for molecular docking to clarify the interaction between the bioactive compounds and FXa. Therefore, the chemical and biological results indicate that compounds 5 (ginsenoside Rg2), 13 (ginsenoside Rg3) and 18 (protopanaxtriol, PPT) are potential natural inhibitors against FXa.
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Affiliation(s)
- Lingxin Xiong
- School of Pharmaceutical Sciences, Jilin University, Fujin Road 1266, Changchun 130021, China.
- National and Local Joint Engineering Research Center for Ginseng Innovative Drugs Development, Western Chaoyang Road 45, Changchun 130021, China.
- Department of Pathogen Biology, Basic Medical College, Jilin University, Changchun 130021, China.
| | - Zeng Qi
- School of Pharmaceutical Sciences, Jilin University, Fujin Road 1266, Changchun 130021, China.
- National and Local Joint Engineering Research Center for Ginseng Innovative Drugs Development, Western Chaoyang Road 45, Changchun 130021, China.
| | - Bingzhen Zheng
- School of Pharmaceutical Sciences, Jilin University, Fujin Road 1266, Changchun 130021, China.
- National and Local Joint Engineering Research Center for Ginseng Innovative Drugs Development, Western Chaoyang Road 45, Changchun 130021, China.
| | - Zhuo Li
- School of Pharmaceutical Sciences, Jilin University, Fujin Road 1266, Changchun 130021, China.
- National and Local Joint Engineering Research Center for Ginseng Innovative Drugs Development, Western Chaoyang Road 45, Changchun 130021, China.
| | - Fang Wang
- Department of Pathogen Biology, Basic Medical College, Jilin University, Changchun 130021, China.
| | - Jinping Liu
- School of Pharmaceutical Sciences, Jilin University, Fujin Road 1266, Changchun 130021, China.
- National and Local Joint Engineering Research Center for Ginseng Innovative Drugs Development, Western Chaoyang Road 45, Changchun 130021, China.
| | - Pingya Li
- School of Pharmaceutical Sciences, Jilin University, Fujin Road 1266, Changchun 130021, China.
- National and Local Joint Engineering Research Center for Ginseng Innovative Drugs Development, Western Chaoyang Road 45, Changchun 130021, China.
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Hack K, Renzi F, Hess E, Lauber F, Douxfils J, Dogné JM, Cornelis GR. Inactivation of human coagulation factor X by a protease of the pathogen Capnocytophaga canimorsus. J Thromb Haemost 2017; 15:487-499. [PMID: 28029716 DOI: 10.1111/jth.13605] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Indexed: 01/13/2023]
Abstract
Essentials Capnocytophaga canimorsus causes severe dog bite related blood stream infections. We investigated if C. canimorsus contributes to bleeding abnormalities during infection. The C. canimorsus protease CcDPP7 causes factor X dysfunction by N-terminal cleavage. CcDPP7 inhibits coagulation in vivo, which could promote immune evasion and trigger hemorrhage. SUMMARY Background Capnocytophaga canimorsus is a Gram-negative bacterium that is present in the oral flora of dogs and causes fulminant sepsis in humans who have been bitten, licked, or scratched. In patients, bleeding abnormalities, such as petechiae, purpura fulminans, or disseminated intravascular coagulation (DIC), occur frequently. Objective To investigate whether C. canimorsus could actively contribute to these bleeding abnormalities. Methods Calibrated automated thrombogram and clotting time assays were performed to assess the anticoagulant activity of C. canimorsus 5 (Cc5), a strain isolated from a fatal human infection. Clotting factor activities were measured with factor-deficient plasma. Factor X cleavage was monitored with the radiolabeled zymogen and western blotting. Mutagenesis of Cc5 genes encoding putative serine proteases was performed to identify the protease that cleaves FX. Protein purification was performed with affinity chromatography. Edman degradation allowed the detection of N-terminal cleavage of FX. Tail bleeding times were measured in mice. Results We found that Cc5 inhibited thrombin generation and increased the prothrombin time and the activated partial thromboplastin time of human plasma via FX cleavage. A mutant that was unable to synthesize a type 7 dipeptidyl peptidase (DPP7) of the S46 serine protease family failed to proteolyse FX. The purified protease (CcDPP7) cleaved FX heavy and light chains from the N-terminus, and was active in vivo after intravenous injection. Conclusions This is, to our knowledge, the first study demonstrating a detailed mechanism for FX inactivation by a bacterial protease, and it is the first functional study associating DPP7 proteases with a potentially pathogenic outcome.
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Affiliation(s)
- K Hack
- Department of Biology, University of Namur, Namur, Belgium
| | - F Renzi
- Department of Biology, University of Namur, Namur, Belgium
| | - E Hess
- Department of Biology, University of Namur, Namur, Belgium
| | - F Lauber
- Department of Biology, University of Namur, Namur, Belgium
| | - J Douxfils
- Department of Pharmacy, University of Namur, Namur, Belgium
| | - J M Dogné
- Department of Pharmacy, University of Namur, Namur, Belgium
| | - G R Cornelis
- Department of Biology, University of Namur, Namur, Belgium
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Sharma M, Iyer JK, Shih N, Majumder M, Mattaparthi VSK, Mukhopadhyay R, Doley R. Daboxin P, a Major Phospholipase A2 Enzyme from the Indian Daboia russelii russelii Venom Targets Factor X and Factor Xa for Its Anticoagulant Activity. PLoS One 2016; 11:e0153770. [PMID: 27089306 PMCID: PMC4835082 DOI: 10.1371/journal.pone.0153770] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/04/2016] [Indexed: 11/21/2022] Open
Abstract
In the present study a major protein has been purified from the venom of Indian Daboia russelii russelii using gel filtration, ion exchange and Rp-HPLC techniques. The purified protein, named daboxin P accounts for ~24% of the total protein of the crude venom and has a molecular mass of 13.597 kDa. It exhibits strong anticoagulant and phospholipase A2 activity but is devoid of any cytotoxic effect on the tested normal or cancerous cell lines. Its primary structure was deduced by N-terminal sequencing and chemical cleavage using Edman degradation and tandem mass spectrometry. It is composed of 121 amino acids with 14 cysteine residues and catalytically active His48 -Asp49 pair. The secondary structure of daboxin P constitutes 42.73% of α-helix and 12.36% of β-sheet. It is found to be stable at acidic (pH 3.0) and neutral pH (pH 7.0) and has a Tm value of 71.59 ± 0.46°C. Daboxin P exhibits anticoagulant effect under in-vitro and in-vivo conditions. It does not inhibit the catalytic activity of the serine proteases but inhibits the activation of factor X to factor Xa by the tenase complexes both in the presence and absence of phospholipids. It also inhibits the tenase complexes when active site residue (His48) was alkylated suggesting its non-enzymatic mode of anticoagulant activity. Moreover, it also inhibits prothrombinase complex when pre-incubated with factor Xa prior to factor Va addition. Fluorescence emission spectroscopy and affinity chromatography suggest the probable interaction of daboxin P with factor X and factor Xa. Molecular docking analysis reveals the interaction of the Ca+2 binding loop; helix C; anticoagulant region and C-terminal region of daboxin P with the heavy chain of factor Xa. This is the first report of a phospholipase A2 enzyme from Indian viper venom which targets both factor X and factor Xa for its anticoagulant activity.
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Affiliation(s)
- Maitreyee Sharma
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur-784028, Assam, India
| | - Janaki Krishnamurthy Iyer
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Norrapat Shih
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Munmi Majumder
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur-784028, Assam, India
| | | | - Rupak Mukhopadhyay
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur-784028, Assam, India
| | - Robin Doley
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur-784028, Assam, India
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Johnston S. A New Generation of Antiplatelet, and Anticoagulant Medication and the Implications for the Dental Surgeon. ACTA ACUST UNITED AC 2016; 42:840-2, 845-6, 849-50 passim. [PMID: 26749792 DOI: 10.12968/denu.2015.42.9.840] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The management of dental patients taking either antiplatelet medication, anticoagulant medication or both has been well established in the previous literature. Recently, new generations of drugs have emerged which are becoming increasingly common, including direct thrombin inhibitors, factor X inhibitors and a new class of oral thienopyridines. The implications of these drugs for the dental surgeon are not yet fully known. Awareness remains low and there is very little information available within the literature on safe use during surgery. This review paper aims to provide some guidance for dental practitioners performing invasive procedures. CPD/CLINICAL RELEVANCE: A new generation of anticoagulant and antiplatelet drugs have serious implications for patients undergoing surgery and their use is increasing.
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Chen H, Zheng D, Abbott J, Liu L, Bartee MY, Long M, Davids J, Williams J, Feldmann H, Strong J, Grau KR, Tibbetts S, Macaulay C, McFadden G, Thoburn R, Lomas DA, Spinale FG, Virgin HW, Lucas A. Myxomavirus-derived serpin prolongs survival and reduces inflammation and hemorrhage in an unrelated lethal mouse viral infection. Antimicrob Agents Chemother 2013; 57:4114-27. [PMID: 23774438 PMCID: PMC3754305 DOI: 10.1128/aac.02594-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 05/30/2013] [Indexed: 01/10/2023] Open
Abstract
Lethal viral infections produce widespread inflammation with vascular leak, clotting, and bleeding (disseminated intravascular coagulation [DIC]), organ failure, and high mortality. Serine proteases in clot-forming (thrombotic) and clot-dissolving (thrombolytic) cascades are activated by an inflammatory cytokine storm and also can induce systemic inflammation with loss of normal serine protease inhibitor (serpin) regulation. Myxomavirus secretes a potent anti-inflammatory serpin, Serp-1, that inhibits clotting factor X (fX) and thrombolytic tissue- and urokinase-type plasminogen activators (tPA and uPA) with anti-inflammatory activity in multiple animal models. Purified serpin significantly improved survival in a murine gammaherpesvirus 68 (MHV68) infection in gamma interferon receptor (IFN-γR) knockout mice, a model for lethal inflammatory vasculitis. Treatment of MHV68-infected mice with neuroserpin, a mammalian serpin that inhibits only tPA and uPA, was ineffective. Serp-1 reduced virus load, lung hemorrhage, and aortic, lung, and colon inflammation in MHV68-infected mice and also reduced virus load. Neuroserpin suppressed a wide range of immune spleen cell responses after MHV68 infection, while Serp-1 selectively increased CD11c(+) splenocytes (macrophage and dendritic cells) and reduced CD11b(+) tissue macrophages. Serp-1 altered gene expression for coagulation and inflammatory responses, whereas neuroserpin did not. Serp-1 treatment was assessed in a second viral infection, mouse-adapted Zaire ebolavirus in wild-type BALB/c mice, with improved survival and reduced tissue necrosis. In summary, treatment with this unique myxomavirus-derived serpin suppresses systemic serine protease and innate immune responses caused by unrelated lethal viral infections (both RNA and DNA viruses), providing a potential new therapeutic approach for treatment of lethal viral sepsis.
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Affiliation(s)
- Hao Chen
- Divisions of Cardiology and Rheumatology, Department of Medicine
- Department of Molecular Genetics and Microbiology
| | - Donghang Zheng
- Divisions of Cardiology and Rheumatology, Department of Medicine
- Department of Molecular Genetics and Microbiology
| | - Jeff Abbott
- College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Liying Liu
- Divisions of Cardiology and Rheumatology, Department of Medicine
| | - Mee Y. Bartee
- Divisions of Cardiology and Rheumatology, Department of Medicine
- Department of Molecular Genetics and Microbiology
| | - Maureen Long
- College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Jennifer Davids
- Divisions of Cardiology and Rheumatology, Department of Medicine
- Department of Molecular Genetics and Microbiology
| | | | - Heinz Feldmann
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - James Strong
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | | | | | | | - Grant McFadden
- Department of Molecular Genetics and Microbiology
- Viron Therapeutics, Inc., London, Ontario, Canada
| | - Robert Thoburn
- Divisions of Cardiology and Rheumatology, Department of Medicine
| | - David A. Lomas
- Division of Pulmonary Medicine, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Francis G. Spinale
- Department of Surgery, Medical University of South Carolina, Department of Cell Biology and Anatomy, South Carolina, USA
| | - Herbert W. Virgin
- Departments of Pathology and Immunology and Molecular Microbiology, Washington University, St Louis, Missouri, USA
| | - Alexandra Lucas
- Divisions of Cardiology and Rheumatology, Department of Medicine
- Department of Molecular Genetics and Microbiology
- Viron Therapeutics, Inc., London, Ontario, Canada
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11
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Abstract
OBJECTIVE To review novel oral anticoagulant (NOAC) trials in the treatment of venous thromboembolism (VTE) and the possible use of risk-stratification tools to guide their use in practice. SCOPE MEDLINE and Cochrane databases were searched to identify relevant journal articles published from January 1982 to February 2013. Additional references were obtained from articles extracted during the database search. FINDINGS NOACs have been developed to optimize VTE management and overcome the limitations of heparin and vitamin K antagonists (VKA). The AMPLIFY and EINSTEIN trials of apixaban and rivaroxaban, respectively, investigated single-drug management of VTE, whereas the edoxaban Hokusai-VTE trial and dabigatran RE-COVER and RE-COVER II trials investigated the use of NOACs with a heparin lead-in. The AMPLIFY and Hokusai-VTE trials are ongoing but the EINSTEIN and RE-COVER trials have demonstrated that rivaroxaban and dabigatran, respectively, are non-inferior to parenteral anticoagulants and warfarin in the management of VTE. Differences in study design complicate the application of study results to clinical practice. There are multiple validated DVT protocols that effectively and safely treat patients in outpatient settings. The pulmonary embolism (PE) severity index (PESI), simplified PESI (sPESI), and other prognostic tools have been used to risk stratify patients with PE by estimating mortality risk to guide outpatient eligibility. CONCLUSIONS NOACs provide physicians with new therapeutic options in the management of VTE. While heparin and VKAs compose the current standard treatment for VTE, their use will likely disappear as physicians grow comfortable with the adoption of NOACs. As studies have not clearly defined the efficacy of these agents in certain patient populations, further data in special patient populations and risk stratification through the use of VTE severity scores could potentially be adapted to guide anticoagulant management and outpatient treatment eligibility.
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Affiliation(s)
- Alex C Spyropoulos
- North Shore/LIJ Health System at Lenox Hill Hospital, Hofstra-North Shore/LIJ School of Medicine, NY, NY, USA
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12
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Gollard R, Rahman S, Ratnasabapathy R. Factor X inhibitor: a fulminant presentation and fatal course of a rare syndrome in a 59-year-old male. Acta Haematol 2012; 129:40-4. [PMID: 23107910 DOI: 10.1159/000342115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 07/10/2012] [Indexed: 11/19/2022]
Abstract
Factor X inhibitors are rare. The few cases documented in the literature have occurred after viral prodromes, in association with cancer, or after exposure to antibiotics. Acquired factor X deficiencies are also rare and their etiology is largely unknown. We report a new case of a factor X inhibitor and review prior cases of both factor X inhibitors and non-amyloidosis-related acquired factor X deficiencies.
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Affiliation(s)
- Russell Gollard
- Cancer and Blood Specialists of Nevada, Henderson, NV 89074, USA.
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13
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Büller HR, Gallus AS, Pillion G, Prins MH, Raskob GE. Enoxaparin followed by once-weekly idrabiotaparinux versus enoxaparin plus warfarin for patients with acute symptomatic pulmonary embolism: a randomised, double-blind, double-dummy, non-inferiority trial. Lancet 2012; 379:123-9. [PMID: 22130488 DOI: 10.1016/s0140-6736(11)61505-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
BACKGROUND Treatment of pulmonary embolism with low-molecular-weight heparin and vitamin K antagonists, such as warfarin, is not ideal. We aimed to assess non-inferiority of idrabiotaparinux, a reversible longlasting indirect inhibitor of activated factor X, to warfarin in patients with acute symptomatic pulmonary embolism. METHODS In our randomised, double-blind, double-dummy, non-inferiority trial, we enrolled adults with objectively documented acute symptomatic pulmonary embolism attending 291 centres in 37 countries. We excluded patients who were pregnant, had active bleeding, kidney failure, or malignant hypertension, or were at high risk of death, bleeding, or adverse reactions to study drugs. We randomly allocated patients to receive 5-10 days' enoxaparin 1·0 mg/kg twice daily followed by subcutaneous idrabiotaparinux (starting dose 3·0 mg) or adjusted-dose warfarin (target international normalised ratio 2·0-3·0); regimens lasted 3 months or 6 months dependent on clinical presentation. Block randomisation was done with a central interactive computerised system, stratified by study centre and intended treatment duration. The primary efficacy outcome was recurrent venous thromboembolism at 99 days after randomisation. We estimated the odds ratio and 95% CI with a Mantel-Haenzsel χ(2) analysis (non-inferiority margin 2·0) in the intention-to-treat population. The main safety outcome was clinically relevant bleeding (major or non-major) in all patients at day 99. This study is registered with ClinicalTrials.gov, number NCT00345618. FINDINGS Between Aug 1, 2006, and Jan 31, 2010, we enrolled 3202 patients aged 18-96 years. 34 (2%) of 1599 patients randomly allocated to receive enoxaparin-idrabiotaparinux and 43 (3%) of 1603 patients randomly allocated to receive enoxaparin-warfarin had recurrent venous thromboembolism (odds ratio 0·79, 95% CI 0·50-1·25; p(non-inferiority)=0·0001). 72 (5%) of 1599 patients in the enoxaparin-idrabiotaparinux group and 106 (7%) of 1603 patients in the enoxaparin-warfarin group had clinically relevant bleeding (0·67, 0·49-0·91; p(superiority)=0·0098). We noted similar differences in outcomes in those patients treated to 6 months. INTERPRETATION Idrabiotaparinux could provide an attractive alternative to warfarin for the long-term treatment of pulmonary embolism, and seems to be associated with reduced bleeding. FUNDING Sanofi-Aventis (Paris, France).
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Affiliation(s)
- Harry R Büller
- Department of Vascular Medicine, Academic Medical Centre, Amsterdam, Netherlands.
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14
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15
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Wautrecht JC. [New developments in antithrombotic care]. Rev Med Brux 2009; 30:392-398. [PMID: 19899386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
For more than 50 years vitamin K antagonists (VKA) have been the gold standard for long-term oral anticoagulant treatment. New anticoagulants are now in extensive clinical development what will probably have a significant impact on daily practice in the near future. Compounds that specifically block activated factor X (FXa) or activated factor II (thrombin) have entered impressive phase III trials. Idraparinux is a long-active derivative from fondaparinux (synthetic pentasaccharide) and is administered subcutaneously. It inhibits indirectly FXa. Apixaban and rivaroxaban are small molecules that directly block FXa following oral administration. Dabigatran is another substance that is administered orally and directly inhibit thrombin. This article will review the potential interest of these new drugs in the modern antithrombotic care. In the meantime, we will briefly discuss two new tools that have been developed to optimalizing the classical VKA anticoagulation: anticoagulation clinics and point-of-care testing of INR that allows self-monitoring.
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Affiliation(s)
- J C Wautrecht
- Service de Pathologie Vasculaire, Hôpital Erasme, Bruxelles.
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16
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Rivaroxaban: new drug. After hip or knee replacement surgery: LMWH is safer. Prescrire Int 2009; 18:151-3. [PMID: 19743567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
(1) The standard anticoagulant therapy for prevention of thrombosis after hip or knee replacement surgery is subcutaneous injection of a low-molecular-weight heparin, such as enoxaparin; (2) Rivaroxaban is an oral factor-Xa inhibitor anticoagulant approved for use in these indications in the European Union; (3) Four double-blind controlled trials in more than 12 000 patients undergoing hip or knee replacement surgery failed to show that rivaroxaban was any more effective than enoxaparin on relevant clinical outcomes; there was no reduction in mortality, nor in the incidence of pulmonary embolism and symptomatic deep venous thrombosis; (4) In the selected populations enrolled in these trials, the bleeding risk was similar in the rivaroxaban and enoxaparin groups. However, it is possible that very underweight or overweight patients have an increased bleeding risk with rivaroxaban; (5) More information is needed on the nephrotoxicity of rivaroxaban, and a risk of mitochondrial toxicity cannot be ruled out. Post-marketing studies also need to focus on the consequences of wound seepage, which is more frequent with rivaroxaban. (6) Rivaroxaban is metabolized by the cytochrome P450 isoenzyme CYP 3A4 and binds to P-glycoprotein, hence a high risk of pharmacokinetic interactions; (7) Rivaroxaban has the advantage of being an oral treatment that does not require laboratory monitoring. However, it seems best to monitor renal function. It should also be noted that there is no effective antidote if severe bleeding occurs; (8) In practice, for frail elderly patients, who are often polymedicated, it seems more prudent to continue using low-molecular-weight heparin, a drug with which we have more experience.
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17
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Fontana P, Bounameaux H. [The new antithrombotics in 2009]. Rev Med Suisse 2009; 5:303-307. [PMID: 19271646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Presently used anticoagulant drugs include parenterally administered compounds (unfractionated heparin, low-molecular-weight heparins and fondaparinux) and oral vitamin K antagonists. Among the new drugs that are still in phase III clinical development in most indications, the oral factor Xa inhibitor rivaroxaban and the oral direct thrombin inhibitor dabigatran etexilate are expected to be soon introduced on the Swiss market for thromboprophylaxis following major orthopedic surgery. Even though aspirin remains the major antiplatelet agent, the questions of combination of antiplatelet agents and loading dose administration patterns of clopidogrel have been intensively studied in recent years. Among the numerous compounds in clinical development, the new thienopyridine prasugrel is certainly the one that is at the most advanced stage.
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Affiliation(s)
- Pierre Fontana
- Service d'angiologie et d'hémostase, Département de médecine interne HUG, 1211 Genève 14.
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18
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Tammen H, Hess R, Rose H, Wienen W, Jost M. Peptidomic analysis of blood plasma after in vivo treatment with protease inhibitors--a proof of concept study. Peptides 2008; 29:2188-95. [PMID: 18804500 DOI: 10.1016/j.peptides.2008.08.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 08/20/2008] [Accepted: 08/20/2008] [Indexed: 11/24/2022]
Abstract
Native peptides can be regarded as surrogate markers for protease activity in biological samples. Analysis of peptides by peptidomics allows to monitor protease activity in vivo and to describe the influence of protease inhibition. To elucidate the potential of peptides as markers for in vivo protease inhibition we analyzed plasma samples from animals treated with either the indirect FXa inhibitor FONDAPARINUX or the dipeptidylpeptidase IV inhibitor AB192. Signals correlating with the treatment were subsequently identified and assessed with respect to protease-dependent consensus cleavage motifs and occurrence of downstream targets. It could be shown that regulated peptides were either substrates, products or downstream targets of the inhibited protease. The results from the present study demonstrate that the in vivo analysis of peptides by peptidomics has the potential to broaden the knowledge of inhibitor related effects in vivo and that this method may pave the way to develop predictive biomarkers.
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Affiliation(s)
- Harald Tammen
- Digilab BioVisioN GmbH, Feodor Lynen Str. 5, 30625 Hannover, Lower Saxony, Germany.
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19
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Hsia CC, Keeney M, Bosco AA, Xenocostas A. Treatment of acquired factor X inhibitor by plasma exchange with concomitant intravenous immunoglobulin and corticosteroids. Am J Hematol 2008; 83:318-20. [PMID: 17975806 DOI: 10.1002/ajh.21105] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A patient with spontaneous hemorrhage from multiple body sites was found to have markedly prolonged international normalized ratio (INR) and activated partial thromboplastin times (aPTT) with incomplete correction of aPTT on mixing studies using normal plasma. The cause of this severe hemorrhage was due to a specific factor X inhibitor. No underlying or associated diseases were found. Initial treatment with fresh frozen plasma, vitamin K, and recombinant activated factor VII (rFVIIa) was unsuccessful. However, therapy utilizing plasma exchange with concomitant intravenous immunoglobulin and corticosteroids resulted in a rapid and sustained normalization of factor X levels with a clinical hemostatic response.
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Affiliation(s)
- Cyrus C Hsia
- Division of Hematology, Department of Medicine, University of Western Ontario and London Health Sciences Centre, London, Ontario, Canada
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20
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Katz BZ, Muhl L, Zwang E, Ilan N, Herishanu Y, Deutsch V, Naparstek E, Vlodavsky I, Preissner KT. Heparanase modulates heparinoids anticoagulant activities via non-enzymatic mechanisms. Thromb Haemost 2007; 98:1193-1199. [PMID: 18064313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A key element for the physiological restriction of blood coagulation at the endothelial cell surface is its non-thrombogenic property, mainly attributed to cell surface heparan sulfate proteoglycans. Heparanase is an endo-beta-D-glucuronidase with specific heparan sulfate degrading activity, which is produced and stored in platelets, and is released upon their activation. We examined the effects of heparanase pro-enzyme on coagulation functions, predominantly under physiological conditions. While heparanase pro-enzyme does not directly affect coagulation protein activities, it has profound effects on heparinoid-mediated regulation of coagulation responses, apparently via mechanisms that do not involve its enzymatic activity. Heparanase pro-enzyme reverses the anti-coagulant activity of unfractionated heparin on the coagulation pathway as well as on thrombin activity. In addition, heparanase pro-enzyme abrogated the factor X inhibitory activity of low-molecular-weight heparin (LMWH). The pro-coagulant effects of the non-active heparanase were also exerted by its major functional heparin-binding peptide. Finally, the effects of heparanase on the activity of factor VII activating protease that is auto-activated by heparinoids indicated a complete antagonistic action of heparanase in this system. Altogether, heparanase pro-coagulant activities that were also demonstrated in plasma samples from patients under LMWH treatment, point to a possible use of this molecule as antagonist for heparinoid treatment.
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Affiliation(s)
- Ben-Zion Katz
- The Hematology Institute, Tel-Aviv Sourasky Medical Center, Tel-Aviv 64239, Israel.
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21
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Chen J, Jones CL, Liu J. Using an enzymatic combinatorial approach to identify anticoagulant heparan sulfate structures. ACTA ACUST UNITED AC 2007; 14:986-93. [PMID: 17884631 PMCID: PMC4809194 DOI: 10.1016/j.chembiol.2007.07.015] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 07/23/2007] [Accepted: 07/27/2007] [Indexed: 11/18/2022]
Abstract
Heparan sulfate (HS) represents a major class of glycans that perform central physiological functions. Emerging HS and glycosaminoglycan microarray techniques are used to interrogate the structure and function relationship to develop novel therapeutic agents. Availability of HS with specific sulfation patterns has been a limiting factor and impedes the accuracy of HS glycomics studies. Although organic synthesis provides oligosaccharides, these may not fully represent the biological functions of polysaccharides. Here, we present a study for developing an enzyme-based approach to synthesize a polysaccharide library with different sulfation patterns. Using different combinations of biosynthetic enzymes, we synthesized eight unique polysaccharides. We discovered that polysaccharides without the iduronic acid residue displayed strong binding affinity to antithrombin and high anti-Xa and anti-IIa activities. The enzyme-based synthetic approach could become a general method for discovering new HS structures with unique biological functions.
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Affiliation(s)
| | | | - Jian Liu
- Corresponding author: Jian Liu, Rm 309, Beard Hall, University of North Carolina, Chapel Hill, NC 27599. Tel.: 919-843-6511; Fax: 919-843-5432;
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22
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Friedewald VE, Bates ER, Granger CB, Yusuf S, Roberts WC. The Editor's Roundtable: arterial thrombosis and acute coronary syndromes. Am J Cardiol 2007; 100:974-80. [PMID: 17826381 DOI: 10.1016/j.amjcard.2007.05.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 05/10/2007] [Indexed: 11/25/2022]
Affiliation(s)
- Vincent E Friedewald
- Department of Internal Medicine, The University of Texas Medical School at Houston, Houston, Texas, USA.
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23
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Hammwöhner M, D'Alessandro A, Wolfram O, Goette A. New Pharmacologic Approaches to Prevent Thromboembolism in Patients with Atrial Fibrillation. Curr Vasc Pharmacol 2007; 5:211-9. [PMID: 17627564 DOI: 10.2174/157016107781024118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Atrial fibrillation (AF) is associated with a 6 fold increased risk for ischemic stroke. Observational studies suggest that one in four to five strokes is due to AF. Depending on the risk profile of an individual patient, the yearly risk for ischemic stroke is between 2% and 14%. AF is accompanied by an increased propensity for atrial clot formation due to a combination of decreased atrial blood flow, increased activity of the platelet/plasmatic coagulation system and prothrombotic changes at the atrial endocardium. This review summarizes the current guidelines for thromboembolic prevention in patients with AF. In many cases, continuous oral anticoagulation therapy (OAT) with vitamin K antagonists (VitKAs) is indicated if AF is accompanied by more than one additional risk factor for thromboembolic complications. However, therapeutic range of VitKAs (Phenprocoumon, Warfarin, and others), the most commonly used oral anticoagulants, is narrow and their use requires regular anticoagulation monitoring. Possibly due to these limitations, about one third of eligible patients are not treated with VitKAs. Furthermore, in many treated patients OAT is not well controlled. Thus, in clinical practice anticoagulation therapy in AF is suboptimal. Therefore, new and more convenient pharmacologic approaches to prevent thromboembolism with i.e. direct thrombin inhibitors (DTI), synthetic polysaccharides (factor Xa Inhibitors), and others are discussed, and their possible future role in the treatment of AF is evaluated.
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24
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Abstract
Fondaparinux is a synthetic, five-saccharide chain, AT-dependent, anti-FXa agent. Studies showed that fondaparinux acts in prevention and treatment of venous thromboembolism and in ischemic heart disease, without significant bleeding risk. The drug inhibits thrombin generation, has long half-life and can be administered once-daily without laboratory monitoring. It may be used in HIT treatment.
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Affiliation(s)
- V Toschi
- Department of Hematology, and Blood Transfusion, Ospedale San Carlo Borromeo, Via Pio II, 3-20153 Milano, Italy.
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25
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Peng ZC, Cai X, Zhang YG, Kong DS, Guo HS, Liang W, Tang QQ, Song HY, Ma D. A novel anti-tissue factor monoclonal antibody with anticoagulant potency derived from synthesized multiple antigenic peptide through blocking FX combination with TF. Thromb Res 2007; 121:85-93. [PMID: 17573098 DOI: 10.1016/j.thromres.2007.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 02/11/2007] [Accepted: 03/02/2007] [Indexed: 10/23/2022]
Abstract
Tissue factor (TF) has been implicated in the pathogenesis of various thrombotic disorders. Monoclonal antibodies (mAb) that specifically target TF may have potential as antithrombotic therapy. We designed a unique TF peptide (TFP) that was specific for the binding site to factor X (FX). This peptide was used to develop TF mAb that block the coagulation cascade by interfering with the combination of FX with the TF/FVIIa complex. Chemically synthesized TFP coupled to polylysine matrix was used as multiple antigenic peptide (TF-MAP) and this was used to immunize Balb/c mice for the preparation of hybridomas. One hybridoma cell line released an antibody, named TF4A12, which had high anticoagulant potency (by dilute prothrombin time assay). Western blotting showed that TF4A12 could bind TF-MAP and the soluble TF extracellular domain (sTF(1-219)). Results of FX activation assay and amidolytic activity assay showed that the anticoagulant ability of TF4A12 is due to blocking FX, but not FVII, binding to TF. Our study identified an efficient method of developing TF mAb that could block the coagulation cascade.
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Affiliation(s)
- Zhuo-Chun Peng
- Key Laboratory of Molecular Medicine, Ministry of Education, Shanghai Medical College, Fudan University, 200032, People's Republic of China
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26
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Peeters MJ, Sydoruk B. Fondaparinux in patients with ST-segment elevation myocardial infarction. JAMA 2006; 296:2088; author reply 2088-9. [PMID: 17077370 DOI: 10.1001/jama.296.17.2088-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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27
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Hartig F, Eller P, Pechlaner C. Fondaparinux in patients with ST-segment elevation myocardial infarction. JAMA 2006; 296:2087; author reply 2088-9. [PMID: 17077369 DOI: 10.1001/jama.296.17.2087-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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28
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Bhala N, Rajasekhar P, Moore I. Fondaparinux in patients with ST-segment elevation myocardial infarction. JAMA 2006; 296:2087-8; author reply 2088-9. [PMID: 17077368 DOI: 10.1001/jama.296.17.2087-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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29
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Nazareth RA, Tomaz LS, Ortiz-Costa S, Atella GC, Ribeiro JMC, Francischetti IMB, Monteiro RQ. Antithrombotic properties of Ixolaris, a potent inhibitor of the extrinsic pathway of the coagulation cascade. Thromb Haemost 2006; 96:7-13. [PMID: 16807644 PMCID: PMC2900789 DOI: 10.1160/th06-02-0105] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Ixolaris is a two-Kunitz tick salivary gland protein identified in Ixodes scapularis that presents extensive sequence homology to TFPI. It binds to FXa or FX as scaffolds and inhibits tissue factor/FVIIa complex (extrinsic Xnase). Differently from TFPI, ixolaris does not bind to the active site cleft of FXa. Instead, complex formation is mediated by the FXa heparin-binding exosite, which may also results in decreased FXa activity into the prothrombinase complex. In this report, we show that recombinant (125)I-ixolaris interacts with rat and human FX in plasma and prolongs the prothrombin time (PT) and activated partial thromboplastin time (aPTT) in vitro. We have also investigated the effects of ixolaris in vivo, using a venous thrombosis model. Subcutaneous (s.c.) or intravenous (i.v.) administration of ixolaris in rats caused a dose-dependent reduction in thrombus formation, with complete inhibition attained at 20 microg/kg and 10 microg/kg, respectively. Antithrombotic effects were observed 3 h after s.c. administration of ixolaris and lasted for 24 h thereafter. Ex vivo experiments showed that ixolaris (up to 100 microg/kg) did not affect the aPTT, while the PT was increased by approximately 0.4-fold at the highest ixolaris concentration. Remarkably, effective antithrombotic doses of ixolaris (20 microg/kg) was not associated with bleeding which was significant only at higher doses of the anticoagulant (40 microg/kg). Our experiments demonstrate that ixolaris is an effective and possibly safe antithrombotic agent in vivo.
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Affiliation(s)
- Rômulo A Nazareth
- Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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Takahashi H, Ebihara S, Okazaki T, Asada M, Sasaki H, Yamaya M. A comparison of the effects of unfractionated heparin, dalteparin and danaparoid on vascular endothelial growth factor-induced tumour angiogenesis and heparanase activity. Br J Pharmacol 2006; 146:333-43. [PMID: 16041398 PMCID: PMC1576289 DOI: 10.1038/sj.bjp.0706344] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Disseminated intravascular coagulation (DIC) is the most common complication of solid tumours. In this study, the effectiveness of three polysaccharide anticoagulants (PSAs), at therapeutic doses, at inhibiting solid tumour growth was investigated. Mice with tumour xenografts were subcutaneously injected with either unfractionated heparin (UFH; 200 units kg(-1) day(-1)), dalteparin (75 units kg(-1) day(-1)) or danaparoid (50 units kg(-1) day(-1)). At these concentrations, these PSAs are equieffective at inhibiting blood coagulation activated factor X. In mice with Lewis lung carcinoma (LLC) tumours dalteparin and, to a lesser extent, UFH inhibited both tumour growth and angiogenesis, whereas danaparoid did not. In contrast, in mice with KLN205 tumours, all the PSAs inhibited tumour growth and angiogenesis. All the PSAs significantly inhibited proliferation, migration of endothelial cells and vessel formation in matrigel plugs containing vascular endothelial growth factor (VEGF) and there were no significant differences between these effects of the PSAs. The PSAs had no effect on endothelial cell tubular formation in vitro. Although all the PSAs inhibited VEGF production in KLN205 tumours in vivo and cells in vitro, in LLC tumours and cells only UFH and dalteparin inhibited VEGF production, whereas danaparoid did not. In both LLC and KLN205 tumours in vivo, heparanase activity was inhibited by UFH and dalteparin, but not by danaparoid. Hence, UFH and dalteparin may be more effective than danaparoid at inhibiting cancer progression in DIC patients with solid tumours, due at least in part to their ability to suppress VEGF and heparanase in tumours.
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Affiliation(s)
- Hidenori Takahashi
- Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Seiryo-machi 1-1, Aoba-ku, Sendai 980-8574, Japan
| | - Satoru Ebihara
- Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Seiryo-machi 1-1, Aoba-ku, Sendai 980-8574, Japan
- Author for correspondence:
| | - Tatsuma Okazaki
- Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Seiryo-machi 1-1, Aoba-ku, Sendai 980-8574, Japan
| | - Masanori Asada
- Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Seiryo-machi 1-1, Aoba-ku, Sendai 980-8574, Japan
| | - Hidetada Sasaki
- Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Seiryo-machi 1-1, Aoba-ku, Sendai 980-8574, Japan
| | - Mutsuo Yamaya
- Department of Geriatric and Respiratory Medicine, Tohoku University School of Medicine, Seiryo-machi 1-1, Aoba-ku, Sendai 980-8574, Japan
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Yusuf S, Mehta SR, Chrolavicius S, Afzal R, Pogue J, Granger CB, Budaj A, Peters RJG, Bassand JP, Wallentin L, Joyner C, Fox KAA. Effects of fondaparinux on mortality and reinfarction in patients with acute ST-segment elevation myocardial infarction: the OASIS-6 randomized trial. JAMA 2006; 295:1519-30. [PMID: 16537725 DOI: 10.1001/jama.295.13.joc60038] [Citation(s) in RCA: 485] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
CONTEXT Despite many therapeutic advances, mortality in patients with acute ST-segment elevation myocardial infarction (STEMI) remains high. The role of additional antithrombotic agents is unclear, especially among patients not receiving reperfusion therapy. OBJECTIVE To evaluate the effect of fondaparinux, a factor Xa inhibitor, when initiated early and given for up to 8 days vs usual care (placebo in those in whom unfractionated heparin [UFH] is not indicated [stratum 1] or unfractionated heparin for up to 48 hours followed by placebo for up to 8 days [stratum 2]) in patients with STEMI. DESIGN, SETTING, AND PARTICIPANTS Randomized double-blind comparison of fondaparinux 2.5 mg once daily or control for up to 8 days in 12,092 patients with STEMI from 447 hospitals in 41 countries (September 2003-January 2006). From day 3 through day 9, all patients received either fondaparinux or placebo according to the original randomized assignment. MAIN OUTCOME MEASURES Composite of death or reinfarction at 30 days (primary) with secondary assessments at 9 days and at final follow-up (3 or 6 months). RESULTS Death or reinfarction at 30 days was significantly reduced from 677 (11.2%) of 6056 patients in the control group to 585 (9.7%) of 6036 patients in the fondaparinux group (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.77-0.96; P = .008); absolute risk reduction, 1.5%; 95% CI, 0.4%-2.6%). These benefits were observed at 9 days (537 [8.9%] placebo vs 444 [7.4%] fondaparinux; HR, 0.83; 95% CI, 0.73-0.94; P = .003, and at study end (857 [14.8%] placebo vs 756 [13.4%] fondaparinux; HR, 0.88; 95% CI, 0.79-0.97; P = .008). Mortality was significantly reduced throughout the study. There was no heterogeneity of the effects of fondaparinux in the 2 strata by planned heparin use. However, there was no benefit in those undergoing primary percutaneous coronary intervention. In other patients in stratum 2, fondaparinux was superior to unfractionated heparin in preventing death or reinfarction at 30 days (HR, 0.82; 95% CI, 0.66-1.02; P = .08) and at study end (HR, 0.77; 95% CI, 0.64-0.93; P = .008). Significant benefits were observed in those receiving thrombolytic therapy (HR, 0.79; P = .003) and those not receiving any reperfusion therapy (HR, 0.80; P = .03). There was a tendency to fewer severe bleeds (79 for placebo vs 61 for fondaparinux; P = .13), with significantly fewer cardiac tamponade (48 vs 28; P = .02) with fondaparinux at 9 days. CONCLUSION In patients with STEMI, particularly those not undergoing primary percutaneous coronary intervention, fondaparinux significantly reduces mortality and reinfarction without increasing bleeding and strokes. TRIAL REGISTRATION ClinicalTrials.gov Identifier NCT00064428.
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Affiliation(s)
- Salim Yusuf
- Department of Medicine, McMaster University and Hamilton Health Sciences, McMaster Clinic, Hamilton General Hospital, Hamilton, Ontario, Canada.
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Montalescot G. [Present and future developments of antithrombotic agents]. Arch Mal Coeur Vaiss 2006; 99 Spec no.3:17-22. [PMID: 16553239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The search for the optimal antithrombotic efficacy to bleeding risk ratio in interventional cardiology has promoted the development of new antithrombotics and to the elaboration of new association strategies. The relatively modest and inconstant antiaggregant effect of 300 mg of clopidogrel has led to the use of higher dosages of 600 mg or 900 mg. The improved biological effects justify clinical evaluation on a larger scale. While waiting for the results of the CHARISMA trial, several studies seem to demonstrate the benefits of long-term administration. New thienopyridines, the leader of which is prasugrel, have powerful biological effects and have already been assessed in larger clinical trials. The anti GPIIb/IIIa molecules, the indications of which have been recently redefined, feature in new administration strategies under evaluation. The use of direct or indirect thrombin antagonists during invasive procedures remains necessary and several molecules are candidates for replacing unfractionated heparin, with a more predictable activity. Low molecule weight heparins have been shown to be easier to use compared with unfractionated heparin. Synthetic factor Xa inhibitors are at an early stage of development. Of the direct thrombin antagonists, bivalirudine provides an improved benefit/risk ratio and is a new option in the catheter laboratory.
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Affiliation(s)
- G Montalescot
- Institut de cardiologie, Groupe hospitalier La Pitié-Salpêtrière, Paris
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Banerjee Y, Mizuguchi J, Iwanaga S, Kini RM. Hemextin AB Complex, a Unique Anticoagulant Protein Complex from Hemachatus haemachatus (African Ringhals Cobra) Venom That Inhibits Clot Initiation and Factor VIIa Activity. J Biol Chem 2005; 280:42601-11. [PMID: 16204244 DOI: 10.1074/jbc.m508987200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During injury or trauma, blood coagulation is initiated by the interaction of factor VIIa (FVIIa) in the blood with freshly exposed tissue factor (TF) to form the TF.FVIIa complex. However, unwanted clot formation can lead to death and debilitation due to vascular occlusion, and hence, anticoagulants are important for the treatment of thromboembolic disorders. Here, we report the isolation and characterization of two synergistically acting anticoagulant proteins, hemextins A and B, from the venom of Hemachatus haemachatus (African Ringhals cobra). N-terminal sequences and CD spectra of the native proteins indicate that these proteins belong to the three-finger toxin family. Hemextin A (but not hemextin B) exhibits mild anticoagulant activity. However, hemextin B forms a complex (hemextin AB complex) with hemextin A and synergistically enhances its anticoagulant potency. Prothrombin time assay showed that these two proteins form a 1:1 complex. Complex formation was supported by size-exclusion chromatography. Using a "dissection approach," we determined that hemextin A and the hemextin AB complex prolong clotting by inhibiting TF.FVIIa activity. The site of anticoagulant effects was supported by their inhibitory effect on the reconstituted TF.FVIIa complex. Furthermore, we demonstrated their specificity of inhibition by studying their effects on 12 serine proteases; the hemextin AB complex potently inhibited the amidolytic activity of FVIIa in the presence and absence of soluble TF. Kinetic studies showed that the hemextin AB complex is a noncompetitive inhibitor of soluble TF.FVIIa amidolytic activity, with a Ki of 50 nm. Isothermal titration calorimetric studies showed that the hemextin AB complex binds directly to FVIIa with a binding constant of 1.62 x 10(5) m(-1). The hemextin AB complex is the first reported natural inhibitor of FVIIa that does not require a scaffold to mediate its inhibitory activity. Molecular interactions of the hemextin AB complex with FVIIa/TF.FVIIa will provide a new paradigm in the search for anticoagulants that inhibit the initiation of blood coagulation.
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Affiliation(s)
- Yajnavalka Banerjee
- Protein Science Laboratory, Department of Biological Sciences, Faculty of Science, National University of Singapore Singapore 117543
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Welty-Wolf KE, Carraway MS, Ortel TL, Ghio AJ, Idell S, Egan J, Zhu X, Jiao JA, Wong HC, Piantadosi CA. Blockade of tissue factor-factor X binding attenuates sepsis-induced respiratory and renal failure. Am J Physiol Lung Cell Mol Physiol 2005; 290:L21-31. [PMID: 16100288 DOI: 10.1152/ajplung.00155.2005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tissue factor expression in sepsis activates coagulation in the lung, which potentiates inflammation and leads to fibrin deposition. We hypothesized that blockade of factor X binding to the tissue factor-factor VIIa complex would prevent sepsis-induced damage to the lungs and other organs. Acute lung injury was produced in 15 adult baboons primed with killed Escherichia coli [1 x 10(9) colony-forming units (CFU)/kg], and then 12 h later, they were given 1 x 10(10) CFU/kg live E. coli by infusion. Two hours after live E. coli, animals received antibiotics with or without monoclonal antibody to tissue factor intravenously to block tissue factor-factor X binding. The animals were monitored physiologically for 34 h before being killed and their tissue harvested. The antibody treatment attenuated abnormalities in gas exchange and lung compliance, preserved renal function, and prevented tissue neutrophil influx and bowel edema relative to antibiotics alone (all P < 0.05). It also attenuated fibrinogen depletion (P < 0.01) and decreased proinflammatory cytokines, e.g., IL-6 and -8 (P < 0.01), in systemic and alveolar compartments. Similar protective effects of the antibody on IL-6 and -8 expression and permeability were found in lipopolysaccharide-stimulated endothelial cells. Blockade of factor X binding to the tissue factor-factor VIIa complex attenuates lung and organ injuries in established E. coli sepsis by attenuating the neutrophilic response and inflammatory pathways.
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Affiliation(s)
- Karen E Welty-Wolf
- Division of Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
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McGlasson DL, Kaczor DA, Krasuski RA, Campbell CL, Kostur MR, Adinaro JT. Effects of pre-analytical variables on the anti-activated factor X chromogenic assay when monitoring unfractionated heparin and low molecular weight heparin anticoagulation. Blood Coagul Fibrinolysis 2005; 16:173-6. [PMID: 15795534 DOI: 10.1097/01.mbc.0000164424.90545.6e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to determine whether the anti-activated factor X (anti-FXa) assay is less affected by pre-analytical variables in monitoring patients on unfractionated heparin (UFH) and low molecular weight heparin (LMWH) than the activated partial thromboplastin time (aPTT). Forty-six subjects receiving either enoxaparin (LMWH) or UFH were randomly selected. Each study subject had six vacutainer tubes (3.8% sodium citrate, 3.2% sodium citrate) drawn by an atraumatic venipuncture. One tube from each set had a blood to anticoagulant ratio of 9: 1. The other tube had an intentional "short-draw" of approximately 6: 1 blood to anticoagulant ratio. All specimens had an aPTT and a chromogenic anti-FXa assay performed on each specimen regardless of heparin type. The aPTT assay mean with the 3.8% sodium citrate tube short-draw tube was statistically different from the other aPTT assays (P = 0.06). However, all six of the mean anti-FXa assays for the UFH and LMWH heparin subjects were not statistically or clinically different (analysis of variance, P = 0.9878 for UFH and P = 0.9060 for LMWH). The intentional short-draw tube did not affect the anti-FXa assay regardless of the anticoagulant. The anti-FXa assay appears to be a better method for monitoring heparin subjects than the aPTT due to the lack of effect of pre-analytical variables.
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Affiliation(s)
- David L McGlasson
- 59th Clinical Research Squadron, Wilford Hall Medical Center, 2200 Berquist Drive, Lackland AFB, TX 78236-5300, USA. david.mcglasson@lackland af.mil
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Abstract
Factor VIIa (FVIIa) is a key serine protease involved in the initiation of the coagulation cascade. It is a glycosylated disulfide-linked heterodimer comprised of an amino-terminal gamma-carboxyglutamic acid-rich (Gla) domain and two epidermal growth factor (EGF)-like domains in the light chain, and a chymotrypsin-like serine protease domain in the heavy chain. FVIIa requires tissue factor (TF), a membrane bound protein, as an essential cofactor for maximal activity towards its biological substrates Factor X, Factor IX and Factor VII (FVII). Inhibition of TF.FVIIa activity may prevent the formation of fibrin clots and thus be useful in the management of thrombotic disease. The development of TF.FVIIa inhibitors to validate this target has been of great interest. A wide array of strategic approaches to inhibiting the biochemical and biological functions of the TF.FVIIa complex has been pursued. This has been greatly aided from our understanding of the structures for TF, FVII, FVIIa, and the TF.FVIIa complex. These approaches have resulted in inhibitors directed specifically towards either FVIIa or TF. Antagonists include active site inhibited FVIIa, TF mutants, anti-TF antibodies, anti-FVII/FVIIa antibodies, naturally-occurring protein inhibitors, peptide exosite inhibitors, and protein and small molecule active site inhibitors. These antagonists can inhibit catalysis directly at the active site as well as impair function by binding to exosites that may interfere with substrate, membrane, or cofactor binding. The rationale of TF.FVIIa as a target and the development, characteristics and biological uses of TF.FVIIa inhibitors are discussed.
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Affiliation(s)
- Robert A Lazarus
- Departments of Protein Engineering, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
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Abstract
Annexin V is a calcium-dependent phospholipid-binding protein that exhibits anticoagulant activity on binding to phosphatidylserine exposed on the activated surfaces of endothelial cells and platelets, inhibiting activation of factor X and prothrombin in the blood coagulation cascade. Sulfatide (galactosylceramide I(3)-sulfate), one of the glycosphingolipids of the platelet cell membrane, is thought to be involved in blood coagulation systems via activation of factor XII. In this study, we examined whether or not annexin V binds to sulfatide and affects the coagulant activity of sulfatide. Solid phase assaying of annexin V revealed that it binds specifically to sulfatide, i.e. not to galactosylceramide or gangliosides, in the presence of calcium ions. Affinity analysis by means of surface plasmon resonance showed that the K(D) of the interaction between annexin V and sulfatide is 1.2 micro M. Kinetic turbidometric assaying of plasma coagulation initiated by CaCl(2) revealed that the coagulation rate in the presence of sulfatide or phosphatidylserine was decreased by annexin V. These results suggest that annexin V regulates coagulability in the blood stream by binding not only to phosphatidylserine but also to sulfatide.
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Affiliation(s)
- Michiru Ida
- The Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610
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Yuan QP, Walke EN, Sheehan JP. The Factor IXa Heparin-Binding Exosite Is a Cofactor Interactive Site: Mechanism for Antithrombin-Independent Inhibition of Intrinsic Tenase by Heparin. Biochemistry 2005; 44:3615-25. [PMID: 15736971 DOI: 10.1021/bi047934a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Therapeutic heparin concentrations selectively inhibit the intrinsic tenase complex in an antithrombin-independent manner. To define the molecular target and mechanism for this inhibition, recombinant human factor IXa with alanine substituted for solvent-exposed basic residues (H92, R170, R233, K241) in the protease domain was characterized with regard to enzymatic activity, heparin affinity, and inhibition by low molecular weight heparin (LMWH). These mutations only had modest effects on chromogenic substrate hydrolysis and the kinetics of factor X activation by factor IXa. Likewise, factor IXa H92A and K241A showed factor IXa-factor VIIIa affinity similar to factor IXa wild type (WT). In contrast, factor IXa R170A demonstrated a 4-fold increase in apparent factor IXa-factor VIIIa affinity and dramatically increased coagulant activity relative to factor IXa WT. Factor IXa R233A demonstrated a 2.5-fold decrease in cofactor affinity and reduced ability to stabilize cofactor half-life relative to wild type, suggesting that interaction with the factor VIIIa A2 domain was disrupted. Markedly (R233A) or moderately (H92A, R170A, K241A) reduced binding to immobilized LMWH was observed for the mutant proteases. Solution competition demonstrated that the EC(50) for LMWH was increased less than 2-fold for factor IXa H92A and K241A but over 3.5-fold for factor IXa R170A, indicating that relative heparin affinity was WT > H92A/K241A > R170A >> R233A. Kinetic analysis of intrinsic tenase inhibition demonstrated that relative affinity for LMWH was WT > K241A > H92A > R170A >> R233A, correlating with heparin affinity. Thus, LMWH inhibits intrinsic tenase by interacting with the heparin-binding exosite in the factor IXa protease domain, which disrupts interaction with the factor VIIIa A2 domain.
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Affiliation(s)
- Qiu-Ping Yuan
- Department of Medicine/Hematology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Abstract
Fondaparinux is the first drug from the pentassaccharide factor X inhibitor class of anticoagulants to be approved for clinical use. It has been shown to be effective in the prevention of deep vein thrombosis in patients undergoing major orthopaedic surgery of the lower limbs. The drug is also being evaluated for use in the acute coronary syndromes and established thromoboembolic events. The pharmacology of fondaparinux is discussed in this review, as well as the major clinical trials involving this drug. Arguments for (and against) the use of this drug are also summarised.
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Affiliation(s)
- Kiat T Tan
- Haemostasis Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham B18 7QH, England UK
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Vandermeulen E, Singelyn F, Vercauteren M, Brichant JF, Ickx BE, Gautier P. Belgian guidelines concerning central neural blockade in patients with drug-induced alteration of coagulation: an update. Acta Anaesthesiol Belg 2005; 56:139-46. [PMID: 16013658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- E Vandermeulen
- Dept. of Anaesthesia, U.Z. Gasthuisberg, Katholieke Universiteit Leuven, Leuven, Belgium
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Annemans L, Minjoulat-Rey MC, De Knock M, Vranckx K, Czarka M, Gabriel S, Haentjens P. Cost consequence analysis of fondaparinux versus enoxaparin in the prevention of venous thromboembolism after major orthopaedic surgery in Belgium. Acta Clin Belg 2004; 59:346-57. [PMID: 15819379 DOI: 10.1179/acb.2004.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Fondaparinux, a selective inhibitor of activated factor X, has been shown to reduce further the risk of venous thromboembolism (VTE) in major orthopaedic surgery compared to the low molecular weight heparin enoxaparin, when both were applied for 7 days after surgery. To compare the expected costs and clinical outcomes of fondaparinux with enoxaparin applied for 7 days after surgery, we conducted a cost-consequence analysis in patients undergoing major orthopaedic surgery, i.e. total hip replacement, total knee replacement and hip fracture repair. Our decision model included endpoints relevant in routine clinical practice and the natural history of VTE over a long term period of 5 years. Costs for prevention, diagnosis and treatment of VTE and its complications were estimated from the Belgian health care payer perspective. Analyses were conducted for different time horizons and for the three indications, separately, and then combined. Overall, our results indicated that the initial investment in fondaparinux (cost per day: 10.39 euros versus 3.74 euros for enoxaparin) was soon compensated by savings due to avoided VTE events, with cost neutrality being achieved after 90 days and further savings being incurred over longer time periods mainly due to avoided post-thrombotic syndromes. These findings were most pronounced in patients undergoing hip fracture repair. Sensitivity analyses showed these findings to be robust for the three indications separately, and combined. We conclude that our analysis of health and economic consequences over a long term period, demonstrates the value for money of fondaparinux versus enoxaparin for the prevention of VTE events after total hip replacement, total knee replacement and hip fracture repair.
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Affiliation(s)
- L Annemans
- Department of Public Health, Ghent University, Ghent, Belgium
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Abstract
Atherothrombosis, defined as atherosclerotic lesion disruption with superimposed thrombus formation, is the major cause of acute coronary syndromes and cardiovascular deaths. It is the leading cause of morbidity and mortality in the industrialized world. Plaque composition, rather than luminal stenosis, is recognized as the major determinant of this disease. Since tissue factor is found within atheroma and also in the bloodstream of atherosclerotic patients, it likely plays a key role in determining both plaque and blood thrombogenicity. Ongoing clinical and preclinical studies are evaluating the therapeutic possibilities of specific inhibition of the tissue factor pathway. Here, we will review the role of tissue factor in atherothrombosis and therapeutic applications.
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Affiliation(s)
- Juan F Viles-Gonzalez
- Cardiovascular Biology Research Laboratory, Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York 10029, USA
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Abstract
Factor X plays a central role in coagulation, being the point of convergence of the extrinsic and intrinsic pathways of blood clotting. It may also act as one of the links between the coagulation and inflammatory pathways. These findings suggest that factor X may represent an attractive target for a new antithrombotic drug. Indeed, a factor X inhibitor, fondaparinux, has already been approved for clinical use to prevent post-operative deep vein thrombosis. Factor X inhibitors are also being evaluated for use in the treatment of the acute coronary syndromes, pulmonary embolism and deep vein thrombosis. Oral factor X inhibitors are also being developed, which may be of use in the outpatient prevention and/or treatment of stroke and thromboembolism.
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Affiliation(s)
- Kiat Tsong Tan
- Haemostasis Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham, B18 7QH, UK.
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Hollenstein UM, Pernerstorfer T, Homoncik M, Hansen JB, Finzen H, Handler S, Jilma B. Effect of factor X inhibition on coagulation activation and cytokine induction in human systemic inflammation. J Infect Dis 2002; 186:1270-6. [PMID: 12402196 DOI: 10.1086/344646] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2002] [Revised: 05/13/2002] [Indexed: 11/03/2022] Open
Abstract
Anticoagulants have gained increasing attention in the treatment of sepsis. This study used danaparoid to investigate the role of factor Xa in endotoxin-induced coagulation and inflammation and its effectiveness when coagulation activation has already occurred. Thirty healthy volunteers were enrolled in the randomized, placebo-controlled trial. Subjects received 2 ng/kg endotoxin and danaparoid 10 min or 3 h thereafter or placebo. Endotoxin increased prothrombin fragment 1+2 (F(1+2)) levels from 0.5 to 7.0 nmol/L at 5 h in the placebo group. Early danaparoid infusion inhibited endotoxin-induced thrombin formation: maximum F(1+2) levels reached only 1.8 nmol/L (P<.01, vs. baseline or placebo). Delayed danaparoid infusion effectively blocked further thrombin formation. However, danaparoid did not alter endotoxin-induced changes in the fibrinolytic system, cytokine levels, activation of leukocytes, or tissue factor expression on monocytes. Danaparoid therefore selectively attenuates endotoxin-induced coagulopathy, even with delayed administration when coagulation activation is well under way.
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Affiliation(s)
- Ursula M Hollenstein
- Department of Clinical Pharmacology, Division of Infectious Diseases, Hanusch Krankenhaus, University of Tromso, Tromso, Norway
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46
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Abstract
JTV-803 (4-[(2-amidino-1,2,3,4-tetrahydroisoquinolin-7-yloxy)methyl]-1-(4-pyridinyl)piperidine-4-carboxylic acid monomethanesulfonate trihydrate), a specific inhibitor of factor Xa, was evaluated in a pig hemodialysis model with ligation of renal arteries. In this model, JTV-803 administered into the dialysis circuit showed an anticoagulant effect (prolongation of dialysis time) at doses of 0.3 mg/kg + 0.3, 1.0 and 3.0 mg/kg/h. The prolongation of dialysis time in the 0.3 mg/kg + 1.0 mg/kg/h JTV-803 group was comparable to that in the 15 U/kg + 7.5 U/kg/h heparin group. The plasma concentrations of JTV-803 following 0.3 mg/kg + 1.0 mg/kg/h infusion of the drug into the dialysis circuit was 500 ng/ml or less, and prothrombin time was 1.5-fold or less than the pretreatment value. JTV-803 was removed by passing the blood through a dialyzer, resulting in a clearance rate of 53.4-81.8%. After the end of dialysis, plasma concentrations of JTV-803 decreased rapidly with time. These results suggest that human factor Xa inhibitor JTV-803 may have good potential as an antithrombotic agent during hemodialysis, with lower likelihood of bleeding after the end of dialysis.
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Affiliation(s)
- Mikio Hayashi
- Central Pharmaceutical Research Institute, Japan Tobacco Inc, 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
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47
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Sternon J. [Recent therapeutic strategies and new drugs]. Rev Med Brux 2002; 23:A390-4. [PMID: 12422466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Recent therapeutic strategies are presenting concerning the use of morphine, benzodiazepines, hypoglycemic agents, glucocorticoids and several specific treatments are indicated. Three new molecules deserve special attention: tiotropium, fondaparinux and omalizumab.
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48
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Schwarz M, Nordt T, Bode C, Peter K. The GP IIb/IIIa inhibitor abciximab (c7E3) inhibits the binding of various ligands to the leukocyte integrin Mac-1 (CD11b/CD18, alphaMbeta2). Thromb Res 2002; 107:121-8. [PMID: 12431477 DOI: 10.1016/s0049-3848(02)00207-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cross-reactivity with integrins other than glycoprotein IIb/IIIa (GP IIb/IIIa) is discussed as a potential reason for the overall clinical benefits of the GP IIb/IIIa-blocking antibody-fragment abciximab. We evaluated whether abciximab binds to the leukocyte integrin Mac-1, whether it inhibits binding of the distinct ligands and thereby may modulate inflammation, cell proliferation and coagulation. Binding of fluorescence-labelled abciximab to phorbolmyristate acetate-stimulated monocytes and to a monocytic cell line (THP-1) could be detected in flow cytometry. The binding of fibrinogen, the inactivated complement factor 3b (iC3b), and the coagulation factor X to Mac-1 could be inhibited by abciximab (10 microg/ml) in vitro. As a functional consequence, the conversion of factor X to factor Xa mediated by Mac-1, as detected by the chromogenic substrate SZ-2222, was impaired by abciximab. Adhesion of THP-1 cells to immobilized intercellular adhesion molecule 1 (ICAM-1) and to fibrinogen was reduced significantly by abciximab. Fibrinogen-mediated cell aggregation was also impaired. In conclusion, we describe binding of abciximab to Mac-1 on stimulated monocytes. Thereby, abciximab inhibits binding of the ligands fibrinogen, ICAM-1, iC3b and factor X. Furthermore, we demonstrated that Mac-1-dependent conversion from factor X to factor Xa is impaired by abciximab, arguing for the direct modulation of the coagulation cascade by abciximab. Overall, the inhibition of Mac-1 could provide additional clinical benefits of abciximab beyond the well-described blockade of GP IIb/IIIa.
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Affiliation(s)
- Meike Schwarz
- Department of Internal Medicine III, University of Freiburg, Freiburg, Germany.
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49
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Bergqvist D, Siegbahn A. [Prophylaxis of postoperative thromboembolism. New alternatives to low-molecular-weight heparin]. Lakartidningen 2002; 99:3039-41. [PMID: 12170516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
For somewhat more than a decade low molecular weight heparins have dominated in the pharmacological prevention of postoperative venous thromboembolism. At present there are some new methods of potential interest both as prophylactic substances but also to better understand the pathophysiology of deep vein thrombosis. These are inhibition of factor VII a/tissue factor complex (NAP, Nematode Anticoagulant Protein), inhibition of activated factor X (the synthetic pentasaccharide fondaparinux) and thrombin inhibition (melagatran and its oral prodrug ximelagatran). They have been shown to be effective in high risk orthopaedic surgery. They have to show their place in the prophylactic arsenal in comparison with low molecular weight heparins (effect, safety, mode of administration, cost-effectiveness).
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Affiliation(s)
- David Bergqvist
- Avdelningen för klinisk kemi, Akademiska sjukhuset, Uppsala.
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50
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Douketis JD, Kinnon K, Crowther MA. Anticoagulant effect at the time of epidural catheter removal in patients receiving twice-daily or once-daily low-molecular-weight heparin and continuous epidural analgesia after orthopedic surgery. Thromb Haemost 2002; 88:37-40. [PMID: 12152674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
In patients who receive co-administered low-molecular-weight heparin (LMWH) and continuous epidural analgesia (CEA) after orthopedic surgery, there is concern about an increased risk of a spinal epidural hematoma. The practice of twice-daily LMWH dosing in North America might, in part, account for the greater number of epidural hematomas reports compared to Europe where once-daily LMWH is used. We performed a prospective cohort study in patients who had orthopedic surgery and received co-administered LMWH and CEA. We investigated the trough anticoagulant effect, as measured by an anti-Xa heparin level, at the time of epidural catheter removal in patients who received twice-daily or once-daily LMWH. Twenty-five patients who received enoxaparin, 30 mg twice-daily, and 25 patients who received dalteparin, 5,000 IU once-daily, had anti-Xa heparin levels measured on the second or third post-operative day at the time of epidural catheter removal. In patients who received twice-daily enoxaparin, or once-daily dalteparin, the anti-Xa heparin level was measured, on average, 10.4 h and 21.8 h, respectively, after the preceding LWMH dose. All 25 patients who received once-daily LMWH had an anti-Xa heparin level < 0.10 U/ml at the time of catheter removal. Of 25 patients who received twice-daily LMWH, the anti-Xa heparin level at the time of catheter removal was > or = 0.20 U/ml in 5 patients (P = 0.050), and > or = 0.10 U/ml in 7 patients (P = 0.009). We conclude that in patients who are receiving co-administered LMWH and CEA after orthopedic surgery, twice-daily but not once-daily LMWH administration is more likely to be associated with a clinically important anticoagulant effect at the time of epidural catheter removal.
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Affiliation(s)
- James D Douketis
- Department of Medicine, McMaster University and St. Joseph's Hospital, Hamilton, Canada.
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