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Macor P, Durigutto P, Argenziano M, Smith-Jackson K, Capolla S, Di Leonardo V, Marchbank K, Tolva VS, Semeraro F, Ammollo CT, Colucci M, Cavalli R, Meroni P, Tedesco F. Plasminogen activator-coated nanobubbles targeting cell-bound β2-glycoprotein I as a novel thrombus-specific thrombolytic strategy. Haematologica 2022. [PMID: 36172817 DOI: 10.3324/haematol.2022.281505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Indexed: 11/09/2022] Open
Abstract
Beta2-glycoprotein I (β2-GPI) is a serum protein widely recognized as the main target of antibodies present in patients with anti-phospholipid syndrome (APS). β2-GPI binds to activated endothelial cells, platelets and leukocytes, key players in thrombus formation. We developed a new targeted thrombolytic agent consisting of nanobubbles (NBs) coated with recombinant tissue plasminogen activator (rtPA) and recombinant antibody specific for cell-bound β2-GPI. The therapeutic efficacy of targeted nanobubbles was evaluated in vitro, using platelet-rich blood clots, and in vivo in three different animal models: 1) thrombosis developed in a rat model of APS; 2) ferric chloride-induced mesenteric thrombosis in rats, and 3) thrombotic microangiopathy in a mouse model of atypical hemolytic uremic syndrome (C3-gain-of-function mice). Targeted nanobubbles bound preferentially to platelets and leukocytes within thrombi and to endothelial cells through β2-GPI expressed on activated cells. In vitro, rtPA-targeted NBs (rtPA-tNBs) induced greater lysis of platelet-rich blood clots than untargeted NBs. In a rat model of APS, administration of rtPA-tNBs caused rapid dissolution of thrombi and, unlike soluble rtPA that induced transient thrombolysis, prevented new thrombus formation. In a rat model of ferric chloride triggered thrombosis, rtPA-tNBs, but not untargeted NBs and free rtPA, induced rapid and persistent recanalization of occluded vessels. Finally, treatment of C3-gain-of-function mice with rtPA-tNBs, that target β2-GPI deposited in kidney glomeruli, decreased fibrin deposition, and improved urinalysis data with a greater efficiency than untargeted NBs. Our findings suggest that targeting cell-bound β2-GPI may represent an efficient and thrombus-specific thrombolytic strategy in both APS-related and APSunrelated thrombotic conditions.
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Affiliation(s)
- Paolo Macor
- Department of Life Sciences, University of Trieste, 34127 Trieste.
| | - Paolo Durigutto
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan
| | - Monica Argenziano
- Department of Scienza e Tecnologia del Farmaco, University of Turin, 10125 Turin
| | - Kate Smith-Jackson
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle
| | - Sara Capolla
- Experimental and Clinical Pharmacology Unit, C.R.O.-IRCCS, 33081 Aviano
| | | | - Kevin Marchbank
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle
| | | | - Fabrizio Semeraro
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari
| | - Concetta T Ammollo
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari
| | - Mario Colucci
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari
| | - Roberta Cavalli
- Department of Scienza e Tecnologia del Farmaco, University of Turin, 10125 Turin
| | - Pierluigi Meroni
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan
| | - Francesco Tedesco
- Istituto Auxologico Italiano, IRCCS, Laboratory of Immuno-Rheumatology, Milan
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Semeraro F, Ammollo CT, Semeraro N, Colucci M. Extracellular histones promote fibrinolysis by single-chain urokinase-type plasminogen activator in a factor seven activating protease-dependent way. Thromb Res 2020; 196:193-199. [PMID: 32891905 DOI: 10.1016/j.thromres.2020.08.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 08/11/2020] [Accepted: 08/21/2020] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Extracellular histones inhibit tissue plasminogen activator (t-PA)-mediated fibrinolysis by modifying fibrin structure and rheological properties. However, other plasminogen activators involved in intravascular and extravascular fibrinolysis have not been considered yet. OBJECTIVES We investigated the effect of histones on fibrinolysis driven by different plasminogen activators. METHODS Clot lysis induced by t-PA, urokinase (u-PA) and its single chain precursor (scu-PA) was evaluated by turbidimetry. Conversion of scu-PA to u-PA and activation of factor seven activating protease (FSAP) were assessed by fluorogenic and chromogenic assays, respectively. RESULTS Histones delayed t-PA- and u-PA-mediated fibrinolysis but strongly accelerated scu-PA-driven clot lysis through the enhancement of scu-PA to u-PA conversion. This effect required a plasma factor identified as FSAP by the following findings: 1) histones enhanced neither scu-PA activation nor scu-PA-mediated clot lysis under purified conditions; 2) in plasma, the enhancement of fibrinolytic activity by histones was abolished by a neutralizing anti-FSAP antibody; and 3) histones promoted the activation of plasma FSAP. The effect of the natural mixture of histones on scu-PA-driven fibrinolysis was differentially recapitulated by the individual recombinant histones, H4 displaying the strongest activity. When complexed to DNA, histones still accelerated scu-PA-mediated fibrinolysis but with a lesser efficiency due to a reduced FSAP activation. Finally, preincubation of histones with heparin or activated protein C, two known inhibitors of histones, further amplified histone-mediated boost of scu-PA-driven fibrinolysis. CONCLUSIONS Enhancement of FSAP-mediated scu-PA activity by histones may play yet unforeseen roles in intravascular fibrinolysis and contribute to extravascular proteolysis and tissue damage.
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Affiliation(s)
- Fabrizio Semeraro
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy.
| | - Concetta T Ammollo
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Nicola Semeraro
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Mario Colucci
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy
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Ammollo CT, Semeraro F, Vitulli A, Dirienzo L, Mezzasoma AM, Semeraro N, Gresele P, Colucci M. FVIII/VWF complex displays a greater pro-haemostatic activity than FVIII preparations devoid of VWF: Study in plasma and cell-based models. Haemophilia 2020; 26:e151-e160. [PMID: 32325538 DOI: 10.1111/hae.14008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/26/2020] [Accepted: 04/01/2020] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Plasma-derived FVIII/VWF complex was reported to be less sensitive to inhibitors than FVIII preparations devoid of VWF. AIM To compare the efficacy of FVIII/VWF complex (Fanhdi) and five different VWF-free FVIII preparations in restoring thrombin generation and activation of thrombin-activatable fibrinolysis inhibitor (TAFI) in haemophilic plasma, with and without inhibitor, and in cell-based models. METHODS Experiments were performed in haemophilic plasma supplemented with inhibitory IgG or in plasma samples obtained from haemophilia A patients without (n = 11) and with inhibitor (n = 12). Thrombin generation was evaluated by calibrated automated thrombography (CAT) under standard conditions, in the presence of activated protein C (APC) or thrombomodulin (TM), and in cell-based models including endothelial cells, either alone or in combination with platelets or tissue factor-expressing blood mononuclear cells. The kinetics of TAFI activation was determined by a two-stage functional assay in the absence and in the presence of APC. RESULTS In haemophilic plasma without inhibitor, Fanhdi enhanced thrombin generation and TAFI activation as well as recombinant (2nd-4th generation) and plasma-derived FVIII preparations devoid of VWF. On the contrary, in plasma with inhibitor, Fanhdi displayed a greater ability to restore thrombin generation and TAFI activation under all tested conditions. Notably, in cell-based models including endothelial cells, Fanhdi proved more efficient than all other preparations in improving thrombin generation even in the absence of inhibitor. CONCLUSION The greater pro-haemostatic activity of FVIII/VWF complex, either in haemophilic plasma with inhibitor or in the presence of endothelial cells, may offer therapeutic advantages.
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Affiliation(s)
- Concetta T Ammollo
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Fabrizio Semeraro
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Antonia Vitulli
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Lavinia Dirienzo
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Anna M Mezzasoma
- Section of Internal and Cardiovascular Medicine, Department of Medicine, University of Perugia, Perugia, Italy
| | - Nicola Semeraro
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Paolo Gresele
- Section of Internal and Cardiovascular Medicine, Department of Medicine, University of Perugia, Perugia, Italy
| | - Mario Colucci
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
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Semeraro F, Mancuso ME, Ammollo CT, Dirienzo L, Vitulli A, Santagostino E, Tripodi A, Colucci M. Thrombin activatable fibrinolysis inhibitor pathway alterations correlate with bleeding phenotype in patients with severe hemophilia A. J Thromb Haemost 2020; 18:381-389. [PMID: 31571361 DOI: 10.1111/jth.14656] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 05/22/2019] [Revised: 09/02/2019] [Accepted: 09/27/2019] [Indexed: 01/31/2023]
Abstract
BACKGROUND Patients with severe hemophilia A display varied bleeding phenotypes despite similar factor VIII (FVIII) activity levels. OBJECTIVE We investigated different thrombin activatable fibrinolysis inhibitor (TAFI)-related variables in patients with severe hemophilia A and their possible correlation with bleeding tendency. PATIENTS/METHODS Sixty-one patients with severe hemophilia A (FVIII:C <1%], treated on demand, were included. Patients were categorized as mild, moderate, and severe bleeders according to number of bleeds per year (≤2, 3-24, ≥25, respectively). Thirty healthy males served as controls. Clot lysis time was assessed by turbidimetric assay, TAFI activation by two-stage functional assay, and response to TAFIa as the prolongation of fibrinolysis time upon addition of purified TAFIa. Circulating levels of activated TAFI (TAFIa/ai) were measured by specific enzyme-linked immunosorbent assay. RESULTS As compared to controls, hemophilic patients displayed shorter lysis time, less TAFIa generation, and reduced response to TAFIa, but similar TAFIa/ai levels. Clot lysis time was similar in mild, moderate, and severe bleeders, whereas TAFIa generation and response to TAFIa decreased with the increase in bleeding tendency; moreover, circulating TAFIa/ai levels were highest in severe bleeders. Patients with markedly impaired TAFIa generation or TAFIa response (below median) displayed 3-fold to 4-fold higher bleeding rate and factor consumption than patients whose TAFI-related values approached the control ones. CONCLUSION The TAFI pathway impairment correlates with bleeding phenotype in severe hemophilia and may represent a promising tool to stratify the bleeding risk.
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Affiliation(s)
- Fabrizio Semeraro
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Maria E Mancuso
- Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Centro Emofilia e Trombosi Angelo Bianchi Bonomi, Milan, Italy
| | - Concetta T Ammollo
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Lavinia Dirienzo
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Antonia Vitulli
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Elena Santagostino
- Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Centro Emofilia e Trombosi Angelo Bianchi Bonomi, Milan, Italy
| | - Armando Tripodi
- Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Centro Emofilia e Trombosi Angelo Bianchi Bonomi, Milan, Italy
- Fondazione Luigi Villa, Milan, Italy
| | - Mario Colucci
- Dipartimento di Scienze Biomediche e Oncologia Umana, Università degli Studi di Bari Aldo Moro, Bari, Italy
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Cerletti C, Colucci M, Storto M, Semeraro F, Ammollo CT, Incampo F, Costanzo S, De Bartolomeo G, Portincasa P, Barone M, Di Castelnuovo A, Semeraro N, Iacoviello L, de Gaetano G. Randomised trial of chronic supplementation with a nutraceutical mixture in subjects with non-alcoholic fatty liver disease. Br J Nutr 2020; 123:190-197. [PMID: 31554528 DOI: 10.1017/s0007114519002484] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [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] [Indexed: 02/07/2023]
Abstract
A mixture of natural ingredients, namely, DHA, phosphatidylcholine, silymarin, choline, curcumin and d-α-tocopherol, was studied in subjects with non-alcoholic fatty liver disease (NAFLD). Primary endpoints were serum levels of hepatic enzymes, and other parameters of liver function, the metabolic syndrome and inflammation were the secondary endpoints. The coagulation-fibrinolysis balance was also thoroughly investigated, as NAFLD is associated with haemostatic alterations, which might contribute to increased cardiovascular risk of this condition. The present study involved a double-blind, randomised, multicentre controlled trial of two parallel groups. Subjects with NAFLD (18-80 years, either sex) received the active or control treatment for 3 months. All assays were performed on a total of 113 subjects before and at the end of supplementation. The hepatic enzymes aspartate aminotransferase (AST), alanine aminotransferase and γ-glutamyl transpeptidase decreased from 23·2 to 3·7 % after treatment, only the AST levels reaching statistical significance. However, no differences were found between control and active groups. Metabolic and inflammatory variables were unchanged, except for a slight (less than 10 %) increase in cholesterol and glucose levels after the active treatment. Coagulation-fibrinolytic parameters were unaffected by either treatment. In conclusion, chronic supplementation with the mixture of dietary compounds was well tolerated and apparently safe in NAFLD subjects. The trial failed to demonstrate any efficacy on relevant physiopathological markers, but its protocol and results may be useful to design future studies with natural compounds.
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Affiliation(s)
- Chiara Cerletti
- Department of Epidemiology and Prevention, IRCCS Neuromed, Pozzilli (IS), Italy
| | - Mario Colucci
- Laboratory for Haemostasis and Thrombosis, Department of Biomedical Sciences and Human Oncology, University "Aldo Moro", Bari, Italy
| | - Marianna Storto
- Clinical Pathology Unit, IRCCS Neuromed, Pozzilli (IS), Italy
| | - Fabrizio Semeraro
- Laboratory for Haemostasis and Thrombosis, Department of Biomedical Sciences and Human Oncology, University "Aldo Moro", Bari, Italy
| | - Concetta T Ammollo
- Laboratory for Haemostasis and Thrombosis, Department of Biomedical Sciences and Human Oncology, University "Aldo Moro", Bari, Italy
| | - Francesca Incampo
- Laboratory for Haemostasis and Thrombosis, Department of Biomedical Sciences and Human Oncology, University "Aldo Moro", Bari, Italy
| | - Simona Costanzo
- Department of Epidemiology and Prevention, IRCCS Neuromed, Pozzilli (IS), Italy
| | | | - Piero Portincasa
- Clinica Medica "A. Murri", Department of Biomedical Sciences and Human Oncology, University "Aldo Moro", Bari, Italy
| | - Michele Barone
- Section of Gastroenterology, Department of Emergency and Organ Transplantation, University "Aldo Moro", Bari, Italy
| | | | - Nicola Semeraro
- Laboratory for Haemostasis and Thrombosis, Department of Biomedical Sciences and Human Oncology, University "Aldo Moro", Bari, Italy
| | - Licia Iacoviello
- Department of Epidemiology and Prevention, IRCCS Neuromed, Pozzilli (IS), Italy
- Department of Medicine and Surgery, Research Center in Epidemiology and Preventive Medicine (EPIMED), University of Insubria, Varese, Italy
| | - Giovanni de Gaetano
- Department of Epidemiology and Prevention, IRCCS Neuromed, Pozzilli (IS), Italy
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Semeraro F, Ammollo CT, Caironi P, Masson S, Latini R, Panigada M, Semeraro N, Gattinoni L, Colucci M. Low D-dimer levels in sepsis: Good or bad? Thromb Res 2019; 174:13-15. [DOI: 10.1016/j.thromres.2018.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/24/2018] [Accepted: 12/03/2018] [Indexed: 11/29/2022]
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Tripodi A, Ammollo CT, Semeraro F, Colucci M, Malchiodi E, Verrua E, Ferrante E, Arnaldi G, Trementino L, Padovan L, Chantarangkul V, Peyvandi F, Mantovani G. Hypercoagulability in patients with Cushing disease detected by thrombin generation assay is associated with increased levels of neutrophil extracellular trap-related factors. Endocrine 2017; 56:298-307. [PMID: 27448294 DOI: 10.1007/s12020-016-1027-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 06/16/2016] [Indexed: 10/21/2022]
Abstract
Patients with Cushing disease (CD) are at increased risk of venous thromboembolism (VTE). It was surmised, but not conclusively shown that the risk is related to plasma hypercoagulability secondary to the glucocorticoids effect. This study is aimed at detecting hypercoagulability in patients with CD. Case-control study of 48 CD patients and controls enrolled at two Italian clinics for whom we assessed the thrombin-forming-potential in the presence of optimal activation of protein C obtained by adding into the assay system its main endothelial activator, thrombomodulin. These experimental conditions mimic more closely than any other test the in vivo situation. We observed enhanced thrombin-generation in CD patients, as shown by the modification of thrombin-generation parameters [i.e., shortened lag-time and time-to-peak, increased thrombin peak and endogenous thrombin potential (ETP)]. Moreover, the ETP ratio (with/without thrombomodulin), recognized as an index of hypercoagulability, was increased in patients as compared to controls. We attempted to explain such hypercoagulability by measuring both procoagulant and anticoagulant factors, and some other non-coagulation parameters (i.e., neutrophil extracellular traps (NET), recently associated with the VTE risk and/or increased hypercoagulability. We showed that the hypercoagulability in patients with CD is associated with increased levels of factor VIII and NET-related variables. We detected plasma hypercoagulability in patients with CD and found experimental explanation for its occurrence. Whether this hypercoagulability can entirely explain the occurrence of VTE in patients with CD should be investigated by ad-hoc clinical trials. However, until these studies will be available the evidence supports the concept that patients with CD are candidates for antithrombotic prophylaxis.
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Affiliation(s)
- Armando Tripodi
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy.
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy.
- IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy.
| | - Concetta T Ammollo
- Department of Biomedical Sciences and Human Oncology, Aldo Moro University, Bari, Italy
| | - Fabrizio Semeraro
- Department of Biomedical Sciences and Human Oncology, Aldo Moro University, Bari, Italy
| | - Mario Colucci
- Department of Biomedical Sciences and Human Oncology, Aldo Moro University, Bari, Italy
| | - Elena Malchiodi
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy
- Unit of Endocrinology and Diabetology, Milano, Italy
- IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy
| | - Elisa Verrua
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy
- Unit of Endocrinology and Diabetology, Milano, Italy
- IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy
| | - Emanuele Ferrante
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy
- Unit of Endocrinology and Diabetology, Milano, Italy
- IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy
| | - Giorgio Arnaldi
- Clinica di Endocrinologia e Malattie del Metabolismo, Ospedali Riuniti di Ancona, Ancona, Italy
| | - Laura Trementino
- Clinica di Endocrinologia e Malattie del Metabolismo, Ospedali Riuniti di Ancona, Ancona, Italy
| | - Lidia Padovan
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy
- IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy
| | - Veena Chantarangkul
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy
- IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy
| | - Flora Peyvandi
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milano, Italy
- IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy
| | - Giovanna Mantovani
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milano, Italy
- Unit of Endocrinology and Diabetology, Milano, Italy
- IRCCS Cà Granda Maggiore Hospital Foundation, Milano, Italy
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Semeraro F, Incampo F, Ammollo CT, Dellanoce C, Paoletti O, Testa S, Colucci M. Dabigatran but not rivaroxaban or apixaban treatment decreases fibrinolytic resistance in patients with atrial fibrillation. Thromb Res 2015; 138:22-29. [PMID: 26826504 DOI: 10.1016/j.thromres.2015.12.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 11/17/2015] [Accepted: 12/23/2015] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Most anticoagulants stimulate fibrinolysis in vitro through mechanisms dependent on and independent of thrombin activatable fibrinolysis inhibitor (TAFI). We evaluated the effect of dabigatran, rivaroxaban and apixaban treatment on plasma fibrinolysis in patients with non-valvular atrial fibrillation. METHODS AND RESULTS Patients treated with dabigatran etexilate (n=22), rivaroxaban (n=24) or apixaban (n=22) were studied. Plasma was obtained before (trough) and 2h after drug intake (peak). Fibrinolytic resistance of clots exposed to exogenous tissue plasminogen activator was significantly lower in peak than in trough samples and correlated with drug concentration only in dabigatran group. Moreover, fibrinolytic resistance at peak was lower in dabigatran than in rivaroxaban and apixaban groups. This difference disappeared if the TAFI pathway was inhibited. Thrombin generation and TAFI activation were markedly lower in peak than in trough samples in all three groups. However, TAFIa levels in trough and peak samples were significantly lower in dabigatran group than in rivaroxaban and apixaban groups. Circulating levels of prothrombin fragment F1+2 (reflecting in vivo thrombin generation) and plasmin-antiplasmin complex (reflecting plasmin generation) were not or barely influenced by drug levels in all groups. CONCLUSIONS Our data suggest that dabigatran, contrary to rivaroxaban and apixaban, reduces fibrinolytic resistance by virtue of its greater impact on TAFI activation. The profibrinolytic effect of dabigatran may play a role locally, at sites of fibrin formation, by making the nascent thrombus more susceptible to plasminogen-dependent degradation.
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Affiliation(s)
- Fabrizio Semeraro
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, University of Bari "Aldo Moro", Bari, Italy
| | - Francesca Incampo
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, University of Bari "Aldo Moro", Bari, Italy
| | - Concetta T Ammollo
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, University of Bari "Aldo Moro", Bari, Italy
| | - Claudia Dellanoce
- Haemostasis and Thrombosis Center, Department of Clinical Pathology, AO Istituti Ospitalieri, Cremona, Italy
| | - Oriana Paoletti
- Haemostasis and Thrombosis Center, Department of Clinical Pathology, AO Istituti Ospitalieri, Cremona, Italy
| | - Sophie Testa
- Haemostasis and Thrombosis Center, Department of Clinical Pathology, AO Istituti Ospitalieri, Cremona, Italy
| | - Mario Colucci
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, University of Bari "Aldo Moro", Bari, Italy.
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Abstract
Coagulopathy is common in acute sepsis and may range from subclinical activation of blood coagulation (hypercoagulability), which may contribute to venous thromboembolism, to acute disseminated intravascular coagulation, characterized by widespread microvascular thrombosis and consumption of platelets and coagulation proteins, eventually causing bleeding. The key event underlying this life-threatening complication is the overwhelming inflammatory host response to the pathogen leading to the overexpression of inflammatory mediators. The latter, along with the microorganism and its derivatives drive the major changes responsible for massive thrombin formation and fibrin deposition: (1) aberrant expression of tissue factor mainly by monocytes-macrophages, (2) impairment of anticoagulant pathways, orchestrated by dysfunctional endothelial cells (ECs), and (3) suppression of fibrinolysis because of the overproduction of plasminogen activator inhibitor-1 by ECs and thrombin-mediated activation of thrombin-activatable fibrinolysis inhibitor. Neutrophils and other cells, upon activation or death, release nuclear materials (neutrophil extracellular traps and/or their components such as histones, DNA, lysosomal enzymes, and High Mobility Group Box-1), which have toxic, proinflammatory and prothrombotic properties thus contributing to clotting dysregulation. The ensuing microvascular thrombosis-ischemia significantly contributes to tissue injury and multiple organ dysfunction syndromes. These insights into the pathogenesis of sepsis-associated coagulopathy may have implications for the development of new diagnostic and therapeutic tools.
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Affiliation(s)
- Nicola Semeraro
- Section of Experimental and Clinical Pathology, Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Concetta T Ammollo
- Section of Experimental and Clinical Pathology, Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Fabrizio Semeraro
- Section of Experimental and Clinical Pathology, Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Mario Colucci
- Section of Experimental and Clinical Pathology, Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
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Ammollo CT, Zaccaria F, Visino F, Testa S, Semeraro N, Colucci M. Influence of cell-associated tissue factor concentration on the anticoagulant activity of dabigatran. A possible explanation for the reduced incidence of intracranial bleeding. Br J Haematol 2014; 168:911-3. [PMID: 25283217 DOI: 10.1111/bjh.13168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Concetta T Ammollo
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, University Aldo Moro, Bari, Italy
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Semeraro F, Ammollo CT, Esmon NL, Esmon CT. Histones induce phosphatidylserine exposure and a procoagulant phenotype in human red blood cells. J Thromb Haemost 2014; 12:1697-702. [PMID: 25069624 PMCID: PMC4194154 DOI: 10.1111/jth.12677] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/17/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Extracellular histones exert part of their prothrombotic activity through the stimulation of blood cells. Besides platelets, histones can bind to red blood cells (RBCs), which are important contributors to thrombogenesis, but little is known about the functional consequences of this interaction. OBJECTIVES To evaluate the effect of histones on the procoagulant potential of human RBCs with particular regard to the expression of surface phosphatidylserine (PS). METHODS PS exposure on human RBCs treated with a natural mixture of histones or recombinant individual histones was evaluated with fluorescein isothiocyanate-annexin-V binding and measured with flow cytometry. Calcium influx in RBCs loaded with the calcium-sensitive fluorophore Fluo-4 AM was assessed with flow cytometry. The procoagulant potential of histone-treated RBCs was evaluated with a purified prothrombinase assay and a one-stage plasma recalcification clotting test. RESULTS Natural histones induced PS exposure on RBCs in a dose-dependent manner, and neutralization or cleavage of histones by heparin or activated protein C, respectively, abolished PS externalization. H4 was mainly responsible for the stimulating activity of histones, whereas the other subtypes were almost ineffective. Similarly, natural histones and H4 induced influx of calcium into RBCs, whereas the other individual histones did not. Histone-induced exposure of PS on RBCs translated into increased prothrombinase complex-mediated prothrombin activation and accelerated fibrin formation in plasma. CONCLUSIONS Histones induce RBCs to express a procoagulant phenotype through the externalization of PS. This finding provides new insights into the prothrombotic activity of extracellular histones.
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Affiliation(s)
- F Semeraro
- Coagulation Biology Laboratory, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
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Semeraro F, Ammollo CT, Gils A, Declerck PJ, Colucci M. Monoclonal antibodies targeting the antifibrinolytic activity of activated thrombin-activatable fibrinolysis inhibitor but not the anti-inflammatory activity on osteopontin and C5a. J Thromb Haemost 2013; 11:2137-47. [PMID: 24134522 DOI: 10.1111/jth.12431] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [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: 05/14/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Recently, anti-thrombin-activatable fibrinolysis inhibitor (TAFI) mAbs selectively inhibiting plasmin-mediated TAFI activation were shown to stimulate fibrinolysis in vitro and in vivo, suggesting, in contrast to other findings, that plasmin-mediated TAFI activation plays an important role in fibrinolysis regulation. OBJECTIVE To further characterize the effects of two plasmin-specific anti-TAFI mAbs (MA-TCK11A9 and MA-TCK26D6) on TAFI-dependent inhibition of fibrinolysis. METHODS AND RESULTS Both mAbs inhibited plasmin-mediated but not thrombin/thrombomodulin-mediated TAFI activation, whereas neither inhibited the cleavage of hippuryl-arginine by activated TAFI (TAFIa). They stimulated tissue-type plasminogen activator-induced fibrinolysis in different clot lysis models through a TAFI-dependent mechanism, especially in the presence of thrombomodulin (TM), a condition in which TAFI is largely activated by the thrombin-TM complex. In a fibrinolysis-based TAFIa activity assay, both mAbs inhibited TAFIa, whereas other mAbs targeting thrombin-TM-mediated TAFI activation did not. The inhibition of TAFIa activity, however, was substrate-specific, because neither mAb inhibited the cleavage of thrombin-activated osteopontin and C5a by TAFIa, thus sparing the anti-inflammatory activity of TAFIa. CONCLUSIONS Our anti-TAFI mAbs, by selectively inhibiting TAFIa activity on fibrin, may represent the prototype of a new class of TAFI inhibitors with improved pharmacologic activity.
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Affiliation(s)
- F Semeraro
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, Aldo Moro University, Bari, Italy
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Ammollo CT, Semeraro F, Colucci M, Simioni P. Factor IX-Padua enhances the fibrinolytic resistance of plasma clots. Thromb Haemost 2013; 111:226-32. [PMID: 24136406 DOI: 10.1160/th13-06-0489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 09/14/2013] [Indexed: 11/05/2022]
Abstract
Hypercoagulable conditions may determine a hypofibrinolytic state by increasing the activation of thrombin-activatable fibrinolysis inhibitor (TAFI). Factor (F)IX-Padua is a mutated FIX with an eight-fold increased clotting activity and associates with a higher venous thrombotic risk. We evaluated the influence of FIX-Padua on TAFI-mediated regulation of fibrinolysis. A subject hemizygous for FIX-Padua, two family members (heterozygous and normal) and six healthy controls were studied. Clot lysis, TAFI activation and thrombin generation were evaluated in contact-inhibited plasma challenged with low concentrations of tissue factor. Fibrinolysis times were significantly longer in FIX-Padua carriers than controls. The difference disappeared when activated TAFI (TAFIa) was inhibited, when TAFI activation was avoided or when clotting was made independent of FIX. TAFIa generation was markedly enhanced in FIX-Padua carriers as compared to controls, and this could be explained by a greater thrombin generation in the former. Hyperactive FIX, but not wild-type FIX, enhanced fibrinolytic resistance also when the FXI-dependent positive feedback was blocked by a neutralising anti-FXI antibody. This thrombin-mediated, TAFI-dependent down-regulation of fibrinolysis provides new clues for explaining the heightened thrombotic risk in subjects carrying the FIX-Padua mutation.
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Affiliation(s)
| | | | | | - Paolo Simioni
- Paolo Simioni, MD, PhD, Department of Cardiologic, Thoracic and Vascular Sciences, 2nd Chair of Internal Medicine, University of Padua Medical School, Via Giustiniani 2 - 35100 Padua, Italy, Tel./Fax: +39 049 8212667, E-mail:
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Ammollo CT, Semeraro F, Xu J, Esmon NL, Esmon CT. Extracellular histones increase plasma thrombin generation by impairing thrombomodulin-dependent protein C activation. J Thromb Haemost 2011; 9:1795-803. [PMID: 21711444 DOI: 10.1111/j.1538-7836.2011.04422.x] [Citation(s) in RCA: 264] [Impact Index Per Article: 20.3] [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: 12/24/2022]
Abstract
BACKGROUND Histones are basic proteins that contribute to cell injury and tissue damage when released into the extracellular space. They have been attributed a prothrombotic activity, because their injection into mice induces diffuse microvascular thrombosis. The protein C-thrombomodulin (TM) system is a fundamental regulator of coagulation, particularly in the microvasculature, and its activity can be differentially influenced by interaction with several cationic proteins. OBJECTIVE To evaluate the effect of histones on the protein C-TM system in a plasma thrombin generation assay and in purified systems. METHODS The effect of histones on plasma thrombin generation in the presence or absence of TM was analyzed by calibrated automated thrombinography. Protein C activation in purified systems was evaluated by chromogenic substrate cleavage. The binding of TM and protein C to histones was evaluated by solid-phase binding assay. RESULTS Histones dose-dependently increased plasma thrombin generation in the presence of TM, independently of its chondroitin sulfate moiety. This effect was not caused by inhibition of activated protein C activity, but by the impairment of TM-mediated protein C activation. Histones were able to bind to both protein C and TM, but the carboxyglutamic acid domain of protein C was required for their effect. Histones H4 and H3 displayed the highest activity. Importantly, unlike heparin, DNA did not inhibit the potentiating effect of histones on thrombin generation. CONCLUSIONS Histones enhance plasma thrombin generation by reducing TM-dependent protein C activation. This mechanism might contribute to microvascular thrombosis induced by histones in vivo at sites of organ failure or severe inflammation.
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Affiliation(s)
- C T Ammollo
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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Carrieri C, Galasso R, Semeraro F, Ammollo CT, Semeraro N, Colucci M. The role of thrombin activatable fibrinolysis inhibitor and factor XI in platelet-mediated fibrinolysis resistance: a thromboelastographic study in whole blood. J Thromb Haemost 2011; 9:154-62. [PMID: 20961395 DOI: 10.1111/j.1538-7836.2010.04120.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [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: 11/29/2022]
Abstract
BACKGROUND The resistance of platelet-rich thrombi to fibrinolysis is generally attributed to clot retraction and platelet PAI-1 release. The role of TAFI in platelet-mediated resistance to lysis is unclear. OBJECTIVE We investigated the contribution of TAFI to the antifibrinolytic effect of platelets in whole blood by thromboelastography. METHODS Platelet-poor (PP-WB, < 40 × 10(3) μL(-1) ) and platelet-rich (PR-WB, > 400 × 10(3) μL(-1) ) blood samples were obtained from normal human blood (N-WB, 150-220 × 10(3) μL(-1) ). Clot lysis time was measured by thromboelastography in recalcified blood supplemented with t-PA (100 ng mL(-1) ) and tissue factor (1:1000 Recombiplastin). RESULTS t-PA-induced lysis time increased in parallel with platelet concentration (up to 3-fold). Neutralization of TAFI, but not of PAI-1, shortened the lysis time by ∼ 50% in PR-WB and by < 10% in PP-WB. Accordingly, prothrombin F1+2 and TAFIa accumulation was greater in PR-WB than in PP-WB. A similar TAFI-dependent inhibition of fibrinolysis was observed when clot retraction was prevented by cytochalasin D or abciximab, or when platelet membranes were tested. Moreover, in blood with an intact contact system, platelet-mediated fibrinolysis resistance was attenuated by an anti-FXI but not by an anti F-XII antibody. Finally, platelets made the clots resistant to the profibrinolytic effect of heparin concentrations displaying a strong anticoagulant activity. CONCLUSIONS Our data indicate that TAFI activation is one major mechanism whereby platelets make clots resistant to fibrinolysis and underscore the importance of TAFI inhibitors as new antithrombotic agents.
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Affiliation(s)
- C Carrieri
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, Aldo Moro University, Bari, Italy
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Ammollo CT, Semeraro F, Incampo F, Semeraro N, Colucci M. Dabigatran enhances clot susceptibility to fibrinolysis by mechanisms dependent on and independent of thrombin-activatable fibrinolysis inhibitor. J Thromb Haemost 2010; 8:790-8. [PMID: 20088944 DOI: 10.1111/j.1538-7836.2010.03739.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [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: 11/29/2022]
Abstract
BACKGROUND Anticoagulants are expected to promote fibrinolysis by counteracting the antifibrinolytic effects of thrombin, which include thrombin-activatable fibrinolysis inhibitor (TAFI) activation and clot structure enhancement. However, the efficiency of anticoagulants may vary remarkably, and the ability of direct thrombin inhibitors to facilitate clot lysis remains controversial. OBJECTIVE To evaluate the profibrinolytic effect of dabigatran, a new, direct thrombin inhibitor, using different in vitro models. METHODS AND RESULTS The resistance of tissue factor-induced plasma clots to fibrinolysis by exogenous tissue-type plasminogen activator (t-PA) (turbidimetric method) was reduced by dabigatran in a concentration-dependent manner, with > or = 50% shortening of lysis time at clinically relevant concentrations (1-2 microm). A similar effect was observed in the presence of low (0.1 and 1 nm) but not high (10 nm) concentrations of thrombomodulin. Acceleration of clot lysis by dabigatran was associated with a reduction in TAFI activation and thrombin generation, and was largely, although not completely, negated by an inhibitor of activated TAFI, potato tuber carboxypeptidase inhibitor. The assessment of the viscoelastic properties of clots showed that those generated in the presence of dabigatran were more permeable, were less rigid, and consisted of thicker fibers. The impact of these physical changes on fibrinolysis was investigated using a model under flow conditions, which demonstrated that dabigatran made the clots markedly more susceptible to flowing t-PA, by a mechanism that was largely TAFI-independent. CONCLUSIONS Dabigatran, at clinically relevant concentrations, enhances the susceptibility of plasma clots to t-PA-induced lysis by reducing TAFI activation and by altering the clot structure. These mechanisms might contribute to the antithrombotic activity of the drug.
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Affiliation(s)
- C T Ammollo
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, University of Bari, Bari, Italy
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Paparella D, Semeraro F, Scrascia G, Galeone A, Ammollo CT, Kounakis G, de Luca Tupputi Schinosa L, Semeraro N, Colucci M. Coagulation-Fibrinolysis Changes During Off-Pump Bypass: Effect of Two Heparin Doses. Ann Thorac Surg 2010; 89:421-7. [DOI: 10.1016/j.athoracsur.2009.10.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 10/15/2009] [Accepted: 10/15/2009] [Indexed: 11/29/2022]
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Xu J, Zhang X, Pelayo R, Monestier M, Ammollo CT, Semeraro F, Taylor FB, Esmon NL, Lupu F, Esmon CT. Extracellular histones are major mediators of death in sepsis. Nat Med 2009; 15:1318-21. [PMID: 19855397 PMCID: PMC2783754 DOI: 10.1038/nm.2053] [Citation(s) in RCA: 1086] [Impact Index Per Article: 72.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Accepted: 09/30/2009] [Indexed: 02/07/2023]
Abstract
Hyperinflammatory responses can lead to a variety of diseases, including sepsis. We now report that extracellular histones released in response to inflammatory challenge contribute to endothelial dysfunction, organ failure and death during sepsis. They can be targeted pharmacologically by antibody to histone or by activated protein C (APC). Antibody to histone reduced the mortality of mice in lipopolysaccharide (LPS), tumor necrosis factor (TNF) or cecal ligation and puncture models of sepsis. Extracellular histones are cytotoxic toward endothelium in vitro and are lethal in mice. In vivo, histone administration resulted in neutrophil margination, vacuolated endothelium, intra-alveolar hemorrhage and macro- and microvascular thrombosis. We detected histone in the circulation of baboons challenged with Escherichia coli, and the increase in histone levels was accompanied by the onset of renal dysfunction. APC cleaves histones and reduces their cytotoxicity. Co-infusion of APC with E. coli in baboons or histones in mice prevented lethality. Blockade of protein C activation exacerbated sublethal LPS challenge into lethality, which was reversed by treatment with antibody to histone. We conclude that extracellular histones are potential molecular targets for therapeutics for sepsis and other inflammatory diseases.
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Affiliation(s)
- Jun Xu
- Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
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Semeraro F, Ammollo CT, Semeraro N, Colucci M. Tissue factor-expressing monocytes inhibit fibrinolysis through a TAFI-mediated mechanism, and make clots resistant to heparins. Haematologica 2009; 94:819-26. [PMID: 19377079 DOI: 10.3324/haematol.2008.000042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Thrombin is the main activator of the fibrinolysis inhibitor TAFI (thrombin activatable fibrinolysis inhibitor) and heightened clotting activation is believed to impair fibrinolysis through the increase of thrombin activatable fibrinolysis inhibitor activation. However, the enhancement of thrombin generation by soluble tissue factor was reported to have no effect on plasma fibrinolysis and it is not known whether the same is true for cell-associated tissue factor. The aim of this study was to evaluate the effect of tissue factor-expressing monocytes on plasma fibrinolysis in vitro. DESIGN AND METHODS Tissue factor expression by human blood mononuclear cells (MNC) and monocytes was induced by LPS stimulation. Fibrinolysis was spectrophotometrically evaluated by measuring the lysis time of plasma clots containing LPS-stimulated or control cells and a low concentration of exogenous tissue plasminogen activator. RESULTS LPS-stimulated MNC (LPS-MNC) prolonged fibrinolysis time as compared to unstimulated MNC (C-MNC) in contact-inhibited but not in normal citrated plasma. A significantly prolonged lysis time was observed using as few as 30 activated cells/microL. Fibrinolysis was also impaired when clots were generated on adherent LPS-stimulated monocytes. The antifibrinolytic effect of LPS-MNC or LPS-monocytes was abolished by an anti-tissue factor antibody, by an antibody preventing thrombin-mediated thrombin activatable fibrinolysis inhibitor activation, and by a TAFIa inhibitor (PTCI). Assays of thrombin and TAFIa in contact-inhibited plasma confirmed the greater generation of these enzymes in the presence of LPS-MNC. Finally, the profibrinolytic effect of unfractionated heparin and enoxaparin was markedly lower (approximately 50%) in the presence of LPS-MNC than in the presence of a thromboplastin preparation displaying an identical tissue factor activity. CONCLUSIONS Our data indicate that LPS-stimulated monocytes inhibit fibrinolysis through a tissue factor-mediated enhancement of thrombin activatable fibrinolysis inhibitor activation and make clots resistant to the profibrinolytic activity of heparins, thus providing an additional mechanism whereby tissue factor-expressing monocytes/macrophages may favor fibrin accumulation and diminish the antithrombotic efficacy of heparins.
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Affiliation(s)
- Fabrizio Semeraro
- Department of Biomedical Sciences and Human Oncology, Section of General and Experimental Pathology, University of Bari, Bari, Italy
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Ammollo CT, Semeraro F, Semeraro N, Colucci M. The contribution of anti-Xa and anti-IIa activities to the profibrinolytic activity of low-molecular-weight heparins. Thromb Haemost 2009; 101:782-785. [PMID: 19350129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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