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Langhorn R, Poulsen MK, Heidemann PL, Bochsen L, Ritz C, Kristensen AT, Nielsen LN. Diagnosis of primary hyperfibrinolysis and in vitro investigation of the inhibitory effects of tranexamic acid in a group of dogs with sarcomas - A pilot study. Res Vet Sci 2021; 136:472-477. [PMID: 33838456 DOI: 10.1016/j.rvsc.2021.03.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 03/24/2021] [Accepted: 03/30/2021] [Indexed: 10/21/2022]
Abstract
Primary hyperfibrinolysis is not well characterised in canine cancer. This prospective case-control pilot study aimed to evaluate tissue plasminogen activator-modified thromboelastography (tPA-TEG) for diagnosis of primary hyperfibrinolysis in dogs with cancer and establish the in vitro therapeutic concentration of tranexamic acid (TXA). Nine dogs with sarcomas and normocoagulable thromboelastograms and 11 healthy dogs were included. For each a whole blood tPA-TEG, and four tPA-TEGs with added TXA in different concentrations were analysed. Lysis percentage at 30/60 min following maximal amplitude (LY30/60), clot lysis index (CL30/60), maximum rate of lysis (MRL), and total lysis (L) were investigated as diagnostic parameters of primary hyperfibrinolysis. In vitro TXA concentrations needed to inhibit 50% (IC50) and 90% (IC90) of the fibrinolytic potential were compared between groups. Significant primary hyperfibrinolysis (LY30 (P = 0.0001), LY60 (P = 0.003), CL30 (P = 0.01), and L (P = 0.02)) was observed in dogs with sarcomas. IC50 and IC90 of in vitro TXA for normalizing LY30 were 13.34 (SE 1.52) and 31.10 (SE 3.01) mg/L for dogs with sarcomas and 4.41 (SE 5.84) and 20.00 (SE 6.18) mg/L for healthy dogs. IC50 and IC90 for normalizing LY60 were 22.18 (SE 1.27) and 58.94 (SE 5.47) mg/L for dogs with sarcomas and 11.25 (SE 2.82) and 56.20 (SE 11.61) mg/L for healthy dogs. The IC50 for LY60 was significantly increased for dogs with sarcomas (P = 0.0003). Primary hyperfibrinolysis was documented by tPA-TEG in dogs with sarcomas. In vitro IC50 and IC90 for TXA were established. Clinical studies are required to establish therapeutic dosages in vivo.
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Affiliation(s)
- Rebecca Langhorn
- Department of Veterinary Clinical Sciences, University of Copenhagen, Dyrlægevej 16, 1870 Frederiksberg C, Denmark.
| | - Matilde K Poulsen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Dyrlægevej 16, 1870 Frederiksberg C, Denmark.
| | - Pernille L Heidemann
- Department of Veterinary Clinical Sciences, University of Copenhagen, Dyrlægevej 16, 1870 Frederiksberg C, Denmark.
| | - Louise Bochsen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Dyrlægevej 16, 1870 Frederiksberg C, Denmark.
| | - Christian Ritz
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Rolighedsvej 25, 1958 Frederiksberg C, Denmark.
| | - Annemarie T Kristensen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Dyrlægevej 16, 1870 Frederiksberg C, Denmark.
| | - Lise N Nielsen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Dyrlægevej 16, 1870 Frederiksberg C, Denmark.
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Abstract
Patients with liver disease acquire complex changes in their hemostatic system. Historically, these patients were considered to have a bleeding tendency related, in part, to a hyperfibrinolytic state. However, studies using more modern fibrinolysis tests have questioned the presence of a hyperfibrinolytic state in patients with liver disease and its association with bleeding risk. It may be that the sickest patients with liver disease do have fibrinolytic abnormalities. However, the debate on the fibrinolytic state of patients with (decompensated) cirrhosis or critically ill liver disease is complicated by the fact that hypo- and hyperfibrinolysis have been poorly defined. This could, in part, be explained by the lack of reliable tests that assess a patient's fibrinolytic status. Moreover, large clinical studies on the relationship between bleeding and fibrinolysis in patients with liver disease are scarce. Here, we provide an overview of the current knowledge on fibrinolysis in various types of liver diseases and possible implications as a target for therapeutic strategies in liver disease. As antifibrinolytic therapy has been shown to be safe and effective during liver transplantation, it could potentially be of use in patients with (either laboratory-established or suspected) hyperfibrinolysis-related bleeding.
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Affiliation(s)
- Fien A von Meijenfeldt
- Section of Hepatobiliary Surgery and Liver Transplantation, Department of Surgery, Surgical Research Laboratory, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ton Lisman
- Section of Hepatobiliary Surgery and Liver Transplantation, Department of Surgery, Surgical Research Laboratory, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Role of Shear Stress and tPA Concentration in the Fibrinolytic Potential of Thrombi. Int J Mol Sci 2021; 22:ijms22042115. [PMID: 33672724 PMCID: PMC7924342 DOI: 10.3390/ijms22042115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/11/2021] [Accepted: 02/13/2021] [Indexed: 11/16/2022] Open
Abstract
The resolution of arterial thrombi is critically dependent on the endogenous fibrinolytic system. Using well-established and complementary whole blood models, we investigated the endogenous fibrinolytic potential of the tissue-type plasminogen activator (tPA) and the intra-thrombus distribution of fibrinolytic proteins, formed ex vivo under shear. tPA was present at physiologically relevant concentrations and fibrinolysis was monitored using an FITC-labelled fibrinogen tracer. Thrombi were formed from anticoagulated blood using a Chandler Loop and from non-anticoagulated blood perfused over specially-prepared porcine aorta strips under low (212 s−1) and high shear (1690 s−1) conditions in a Badimon Chamber. Plasminogen, tPA and plasminogen activator inhibitor-1 (PAI-1) concentrations were measured by ELISA. The tPA–PAI-1 complex was abundant in Chandler model thrombi serum. In contrast, free tPA was evident in the head of thrombi and correlated with fibrinolytic activity. Badimon thrombi formed under high shear conditions were more resistant to fibrinolysis than those formed at low shear. Plasminogen and tPA concentrations were elevated in thrombi formed at low shear, while PAI-1 concentrations were augmented at high shear rates. In conclusion, tPA primarily localises to the thrombus head in a free and active form. Thrombi formed at high shear incorporate less tPA and plasminogen and increased PAI-1, thereby enhancing resistance to degradation.
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Tahtamouni LH, Hamdan MN, Al-Mazaydeh ZA, Bawadi RM, Rammaha MS, Zghoul AM, Ahram MA, Yasin SR. Alu-repeat polymorphism in the tissue plasminogen activator ( t-PA) gene, seminal t-PA concentration, and male fertility impairment: A case-control study. Int J Reprod Biomed 2020; 18:571-578. [PMID: 32930675 PMCID: PMC7457157 DOI: 10.18502/ijrm.v13i8.7496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 11/09/2019] [Accepted: 01/14/2020] [Indexed: 11/24/2022] Open
Abstract
Background Tissue plasminogen activator (t-PA) is a protein involved in the fibrinolytic system that catalyzes the conversion of plasminogen into the active plasmin. The activity of t-PA is controlled by plasminogen activator inhibitor-1. t-PA has crucial functions during spermatogenesis. One polymorphism was reported for t-PA gene, either the presence of a 300-bp Alu-repeat (Alu + ) or its absence (Alu - ). Objective The current work aimed at studying the association between Alu polymorphism in the t-PA gene and male infertility. Materials and Methods Using polymerase chain reaction on genomic DNA isolated from the blood of 79 participants, a region polymorphic for Alu element insertion in t-PA gene was amplified. In addition, total t-PA concentration, plasminogen activator inhibitor-1 /t-PA complex concentration, and t-PA activity in seminal plasma were measured by enzyme-linked immunosorbent assay. Results The results indicate that the percentage of infertile participants (n = 50) who were homozygous for t-PA Alu insertion (Alu + / + ), heterozygous Alu + / - or homozygous for t-PA Alu deletion (Alu - / - ) did not change significantly (p = 0.43, 0.81, and 0.85, respectively) when compared with the control participants (n = 29). On the other hand, a significant decrease (p = 0.0001) of t-PA total concentration in seminal plasma was observed in the infertile group in comparison with the control group. However, the results indicate that there is no association between the t-PA Alu different genotypes and the total t-PA seminal concentration in the infertile group when compared to the control group (p = 0.63). Conclusion Data obtained from the current study does not support an association between t-PA Alu polymorphism and t-PA seminal concentration or male infertility.
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Affiliation(s)
- Lubna Hamid Tahtamouni
- Department of Biology and Biotechnology, Faculty of Science, the Hashemite University, Zarqa, Jordan.,Department of Biochemistry and Molecular Biology, College of Natural Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Mahmoud Nael Hamdan
- Department of Biology and Biotechnology, Faculty of Science, the Hashemite University, Zarqa, Jordan
| | - Zainab Ali Al-Mazaydeh
- Department of Biology and Biotechnology, Faculty of Science, the Hashemite University, Zarqa, Jordan
| | - Randa Mahmoud Bawadi
- Department of Physiology and Biochemistry, School of Medicine, the University of Jordan, Amman, Jordan
| | - Majdoleen Sobhi Rammaha
- Department of Biology and Biotechnology, Faculty of Science, the Hashemite University, Zarqa, Jordan
| | - Ahmad Mohammad Zghoul
- Department of Biology and Biotechnology, Faculty of Science, the Hashemite University, Zarqa, Jordan
| | - Mamoun Ahmad Ahram
- Department of Physiology and Biochemistry, School of Medicine, the University of Jordan, Amman, Jordan
| | - Salem Refat Yasin
- Department of Biology and Biotechnology, Faculty of Science, the Hashemite University, Zarqa, Jordan
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Clot formation and lysis in platelet rich plasma of healthy donors and patients with resistant hypertension. UKRAINIAN BIOCHEMICAL JOURNAL 2018. [DOI: 10.15407/ubj90.02.067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Overwhelming tPA release, not PAI-1 degradation, is responsible for hyperfibrinolysis in severely injured trauma patients. J Trauma Acute Care Surg 2016; 80:16-23; discussion 23-5. [PMID: 26491796 DOI: 10.1097/ta.0000000000000885] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Trauma-induced coagulopathy (TIC) is associated with a fourfold increased risk of mortality. Hyperfibrinolysis is a component of TIC, but its mechanism is poorly understood. Plasminogen activation inhibitor (PAI-1) degradation by activated protein C has been proposed as a mechanism for deregulation of the plasmin system in hemorrhagic shock, but in other settings of ischemia, tissue plasminogen activator (tPA) has been shown to be elevated. We hypothesized that the hyperfibrinolysis in TIC is not the result of PAI-1 degradation but is driven by an increase in tPA, with resultant loss of PAI-1 activity through complexation with tPA. METHODS Eighty-six consecutive trauma activation patients had blood collected at the earliest time after injury and were screened for hyperfibrinolysis using thrombelastography (TEG). Twenty-five hyperfibrinolytic patients were compared with 14 healthy controls using enzyme-linked immunosorbent assays for active tPA, active PAI-1, and PAI-1/tPA complex. Blood was also subjected to TEG with exogenous tPA challenge as a functional assay for PAI-1 reserve. RESULTS Total levels of PAI-1 (the sum of the active PAI-1 species and its covalent complex with tPA) are not significantly different between hyperfibrinolytic trauma patients and healthy controls: median, 104 pM (interquartile range [IQR], 48-201 pM) versus 115 pM (IQR, 54-202 pM). The ratio of active to complexed PAI-1, however, was two orders of magnitude lower in hyperfibrinolytic patients than in controls. Conversely, total tPA levels (active + complex) were significantly higher in hyperfibrinolytic patients than in controls: 139 pM (IQR, 68-237 pM) versus 32 pM (IQR, 16-37 pM). Hyperfibrinolytic trauma patients displayed increased sensitivity to exogenous challenge with tPA (median LY30 of 66.8% compared with 9.6% for controls). CONCLUSION Depletion of PAI-1 in TIC is driven by an increase in tPA, not PAI-1 degradation. The tPA-challenged TEG, based on this principle, is a functional test for PAI-1 reserves. Exploration of the mechanism of up-regulation of tPA is critical to an understanding of hyperfibrinolysis in trauma. LEVEL OF EVIDENCE Prognostic and epidemiologic study, level II.
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Dependence of Proximal GC Boxes and Binding Transcription Factors in the Regulation of Basal and Valproic Acid-Induced Expression of t-PA. Int J Vasc Med 2016; 2016:7928681. [PMID: 26966581 PMCID: PMC4761389 DOI: 10.1155/2016/7928681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 12/18/2015] [Accepted: 12/27/2015] [Indexed: 01/09/2023] Open
Abstract
Objective. Endothelial tissue-type plasminogen activator (t-PA) release is a pivotal response to protect the circulation from occluding thrombosis. We have shown that the t-PA gene is epigenetically regulated and greatly induced by the histone deacetylase (HDAC) inhibitor valproic acid (VPA). We now investigated involvement of known t-PA promoter regulatory elements and evaluated dependence of potential interacting transcription factors/cofactors. Methods. A reporter vector with an insert, separately mutated at either the t-PA promoter CRE or GC box II or GC box III elements, was transfected into HT-1080 and HUVECs and challenged with VPA. HUVECs were targeted with siRNA against histone acetyl transferases (HAT) and selected transcription factors from the Sp/KLF family. Results. An intact VPA-response was observed with CRE mutated constructs, whereas mutation of GC boxes II and III reduced the magnitude of the induction by 54 and 79% in HT-1080 and 49 and 50% in HUVECs, respectively. An attenuated induction of t-PA mRNA was observed after Sp2, Sp4, and KLF5 depletion. KLF2 and p300 (HAT) were identified as positive regulators of basal t-PA expression and Sp4 and KLF9 as repressors. Conclusion. VPA-induced t-PA expression is dependent on the proximal GC boxes in the t-PA promoter and may involve interactions with Sp2, Sp4, and KLF5.
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Magnusson M, Lu EX, Larsson P, Ulfhammer E, Bergh N, Carén H, Jern S. Dynamic Enhancer Methylation--A Previously Unrecognized Switch for Tissue-Type Plasminogen Activator Expression. PLoS One 2015; 10:e0141805. [PMID: 26509603 PMCID: PMC4625093 DOI: 10.1371/journal.pone.0141805] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 10/13/2015] [Indexed: 02/05/2023] Open
Abstract
Tissue-type plasminogen activator (t-PA), which is synthesized in the endothelial cells lining the blood vessel walls, is a key player in the fibrinolytic system protecting the circulation against occluding thrombus formation. Although classical gene regulation has been quite extensively studied in order to understand the mechanisms behind t-PA regulation, epigenetics, including DNA methylation, still is a largely unexplored field. The aim of this study was to establish the methylation pattern in the t-PA promoter and enhancer in non-cultured compared to cultured human umbilical vein endothelial cells (HUVECs), and to simultaneously examine the level of t-PA gene expression. Bisulphite sequencing was used to evaluate the methylation status, and real-time RT-PCR to determine the gene expression level. While the t-PA promoter was stably unmethylated, we surprisingly observed a rapid reduction in the amount of methylation in the enhancer during cell culturing. This demethylation was in strong negative correlation with a pronounced (by a factor of approximately 25) increase in t-PA gene expression levels. In this study, we show that the methylation level in the t-PA enhancer appears to act as a previously unrecognized switch controlling t-PA expression. Our findings, which suggest that DNA methylation is quite dynamic, have implications also for the interpretation of cell culture experiments in general, as well as in a wider biological context.
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Affiliation(s)
- Mia Magnusson
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Emma Xuchun Lu
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Pia Larsson
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Erik Ulfhammer
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Bergh
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Helena Carén
- Sahlgrenska Cancer Center, Department of Pathology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail: (HC); (SJ)
| | - Sverker Jern
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail: (HC); (SJ)
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Kandhai-Ragunath JJ, Jørstad HT, de Wagenaar B, de Man FH, Stoel MG, van Es J, Doelman CJ, Doggen CJ, Peters RJ, von Birgelen C. Assessment of the relation between initial culprit vessel patency in acute ST-elevation myocardial infarction and endothelial function. EUROINTERVENTION 2014; 10:784-91. [DOI: 10.4244/eijv10i7a137] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Fletcher DJ, Blackstock KJ, Epstein K, Brainard BM. Evaluation of tranexamic acid and ε-aminocaproic acid concentrations required to inhibit fibrinolysis in plasma of dogs and humans. Am J Vet Res 2014; 75:731-8. [PMID: 25061704 DOI: 10.2460/ajvr.75.8.731] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine minimum plasma concentrations of the antifibrinolytic agents tranexamic acid (TEA) and ε-aminocaproic acid (EACA) needed to completely inhibit fibrinolysis in canine and human plasma after induction of hyperfibrinolysis. SAMPLES Pooled citrated plasma from 7 dogs and commercial pooled citrated human plasma. PROCEDURES Concentrations of EACA from 0 μg/mL to 500 μg/mL and of TEA from 0 μg/mL to 160 μg/mL were added to pooled citrated canine and human plasma. Hyperfibrinolysis was induced with 1,000 units of tissue plasminogen activator/mL, and kaolin-activated thromboelastography was performed in duplicate. The minimum concentrations required to completely inhibit fibrinolysis 30 minutes after maximum amplitude of the thromboelastography tracing occurred were determined. RESULTS Minimum plasma concentrations necessary for complete inhibition of fibrinolysis by EACA and TEA in pooled canine plasma were estimated as 511.7 μg/mL (95% confidence interval [CI], 433.2 to 590.3 μg/mL) and 144.7 μg/mL (95% CI, 125.2 to 164.2 μg/mL), respectively. Concentrations of EACA and TEA necessary for complete inhibition of fibrinolysis in pooled human plasma were estimated as 122.0 μg/mL (95% CI, 106.2 to 137.8 μg/mL) and 14.7 μg/mL (95% CI, 13.7 to 15.6 μg/mL), respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results supported the concept that dogs are hyperfibrinolytic, compared with humans. Higher doses of EACA and TEA may be required to fully inhibit fibrinolysis in dogs.
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Affiliation(s)
- Daniel J Fletcher
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853
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Saluveer O, Larsson P, Ridderstråle W, Hrafnkelsdóttir TJ, Jern S, Bergh N. Profibrinolytic effect of the epigenetic modifier valproic acid in man. PLoS One 2014; 9:e107582. [PMID: 25295869 PMCID: PMC4189785 DOI: 10.1371/journal.pone.0107582] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 08/08/2014] [Indexed: 11/18/2022] Open
Abstract
AIMS The aim of the study was to test if pharmacological intervention by valproic acid (VPA) treatment can modulate the fibrinolytic system in man, by means of increased acute release capacity of tissue plasminogen activator (t-PA) as well as an altered t-PA/Plasminogen activator inhibitor -1 (PAI-1) balance. Recent data from in vitro research demonstrate that the fibrinolytic system is epigenetically regulated mainly by histone deacetylase (HDAC) inhibitors. HDAC inhibitors, including VPA markedly upregulate t-PA gene expression in vitro. METHODS AND RESULTS The trial had a cross-over design where healthy men (n = 10), were treated with VPA (Ergenyl Retard) 500 mg depot tablets twice daily for 2 weeks. Capacity for stimulated t-PA release was assessed in the perfused-forearm model using intra-brachial Substance P infusion and venous occlusion plethysmography. Each subject was investigated twice, untreated and after VPA treatment, with 5 weeks wash-out in-between. VPA treatment resulted in considerably decreased levels of circulating PAI-1 antigen from 22.2 (4.6) to 10.8 (2.1) ng/ml (p<0.05). It slightly decreased the levels of circulating venous t-PA antigen (p<0.05), and the t-PA:PAI-1 antigen ratio increased (p<0.01). Substance P infusion resulted in an increase in forearm blood flow (FBF) on both occasions (p<0.0001 for both). The acute t-PA release in response to Substance P was not affected by VPA (p = ns). CONCLUSION Valproic acid treatment lowers plasma PAI-1 antigen levels and changes the fibrinolytic balance measured as t-PA/PAI-1 ratio in a profibrinolytic direction. This may in part explain the reduction in incidence of myocardial infarctions by VPA treatment observed in recent pharmacoepidemiological studies. TRIAL REGISTRATION The EU Clinical Trials Register 2009-011723-31.
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Affiliation(s)
- Ott Saluveer
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
| | - Pia Larsson
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Wilhelm Ridderstråle
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Thórdís J. Hrafnkelsdóttir
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Cardiology, Landspitali University Hospital and the University of Iceland, Reykjavik, Iceland
| | - Sverker Jern
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Bergh
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Dow CA, Stauffer BL, Greiner JJ, DeSouza CA. Influence of dietary saturated fat intake on endothelial fibrinolytic capacity in adults. Am J Cardiol 2014; 114:783-8. [PMID: 25052545 PMCID: PMC4357274 DOI: 10.1016/j.amjcard.2014.05.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/30/2014] [Accepted: 05/30/2014] [Indexed: 12/01/2022]
Abstract
Approximately 50% of middle-aged and older adults in the United States regularly consume a diet high in saturated fat. High dietary saturated fat intake has been linked to promote atherothrombotic vascular disease. We tested the hypothesis that endothelial fibrinolytic function is diminished in middle-aged and older adults who habitually consume a diet high in saturated fat. Twenty-four healthy, sedentary middle-aged, and older adults (54 to 71 years) were studied: 10 (8 men and 2 women) with a dietary saturated fat intake <10% (lower saturated fat) of total calories and 14 (9 men and 5 women) with a dietary saturated fat intake ≥10% of total calories (high saturated fat). Net endothelial release of tissue-type plasminogen activator (t-PA), the primary activator of fibrinolysis, was determined, in vivo, in response to intrabrachial infusions of bradykinin (12.5 to 50.0 ng/100 ml tissue/min) and sodium nitroprusside (1.0 to 4.0 μg/100 ml tissue/min). Capacity of the endothelium to release t-PA in response to bradykinin was ∼30% less (p <0.05) in the high (from -0.7 ± 0.6 to 36.9 ± 3.3 ng/100 ml tissue/min) compared with the lower (from -0.3 ± 0.3 to 53.4 ± 7.8 ng/100 ml tissue/min) dietary saturated fat group. Moreover, total amount of t-PA released was significantly less (∼30%) (201 ± 22 vs 274 ± 29 ng/100 ml tissue) in the adults who reported consuming a diet high in saturated fat. These results indicate that the capacity of the endothelium to release t-PA is lower in middle-aged and older adults who habitually consume a diet high in saturated fat. In conclusion, endothelial fibrinolytic dysfunction may underlie the increased atherothrombotic disease risk with a diet high in saturated fat.
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Affiliation(s)
- Caitlin A Dow
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Brian L Stauffer
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado; Department of Medicine, University of Colorado Denver and the Health Sciences Center, Aurora, Colorado; Denver Health Medical Center, Denver, Colorado
| | - Jared J Greiner
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Christopher A DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado; Department of Medicine, University of Colorado Denver and the Health Sciences Center, Aurora, Colorado.
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Aspelin T, Eriksen M, Ilebekk A, Cataliotti A, Carlson CR, Lyberg T. β-blockade abolishes the augmented cardiac tPA release induced by transactivation of heterodimerised bradykinin receptor-2 and β2-adrenergic receptor in vivo. Thromb Haemost 2014; 112:951-9. [PMID: 25078038 DOI: 10.1160/th14-01-0059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 06/16/2014] [Indexed: 11/05/2022]
Abstract
Bradykinin (BK) receptor-2 (B2R) and β2-adrenergic receptor (β2AR) have been shown to form heterodimers in vitro. However, in vivo proofs of the functional effects of B2R-β2AR heterodimerisation are missing. Both BK and adrenergic stimulation are known inducers of tPA release. Our goal was to demonstrate the existence of B2R-β2AR heterodimerisation in myocardium and to define its functional effect on cardiac release of tPA in vivo. We further investigated the effects of a non-selective β-blocker on this receptor interplay. To investigate functional effects of B2R-β2AR heterodimerisation (i. e. BK transactivation of β2AR) in vivo, we induced serial electrical stimulation of cardiac sympathetic nerves (SS) in normal pigs that underwent concomitant BK infusion. Both SS and BK alone induced increases in cardiac tPA release. Importantly, despite B2R desensitisation, simultaneous BK infusion and SS (BK+SS) was characterised by 2.3 ± 0.3-fold enhanced tPA release compared to SS alone. When β-blockade (propranolol) was introduced prior to BK+SS, tPA release was inhibited. A persistent B2R-β2AR heterodimer was confirmed in BK-stimulated and non-stimulated left ventricular myocardium by immunoprecipitation studies and under non-reducing gel conditions. All together, these results strongly suggest BK transactivation of β2AR leading to enhanced β2AR-mediated release of tPA. Importantly, non-selective β-blockade inhibits both SS-induced release of tPA and the functional effects of B2R-β2AR heterodimerisation in vivo, which may have important clinical implications.
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Affiliation(s)
- Trude Aspelin
- Trude Aspelin, Institute for Experimental Medical Research, Oslo University Hospital, Ullevål, Postbox 4956 Nydalen, 0424 Oslo, Norway, Tel.: +47 22119685, Fax: +47 23016799, E-mail:
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Siahkouhian M, Khodadadi D, Bolboli L. Diurnal variation of haemostatic response to exercise in young sedentary males. Biol Sport 2014; 30:125-30. [PMID: 24744478 PMCID: PMC3944575 DOI: 10.5604/20831862.1044457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2012] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to evaluate diurnal variations in the haemostatic response to submaximal exercise performed by young, sedentary men. Fifteen healthy young sedentary males aged 25.6 ± 1.34 (mean ± SD) years performed two exercise sessions, morning and evening, at 70% of maximal oxygen consumption (V.O2max) on a cycle ergometer for 30 min. Platelet count (PC), activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) activity were measured as dependent variables. Exercise produced significant increases in PC and fibrinogen for both sessions (P ≤ 0.05), which returned to the resting values after recovery only in the evening session. APTT and PT shortened immediately after exercise, which remained after recovery for both sessions (P ≤ 0.01). Exercise presented significant increases in tPA activity (P ≤ 0.001), which returned to the baseline after recovery in both exercises. PAI-1 activity was significantly higher during the morning than evening (P ≤ 0.05), but no longer demonstrated exercise-related changes. It was found that exercise caused activation of both coagulation and fibrinolysis processes, partly related to the time of the day when the exercise was performed.
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Affiliation(s)
- M Siahkouhian
- Department of Physical Education & Sport Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
| | - D Khodadadi
- Department of Physical Education & Sport Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
| | - L Bolboli
- Department of Physical Education & Sport Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
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15
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Kruithof EKO, Dunoyer-Geindre S. Human tissue-type plasminogen activator. Thromb Haemost 2014; 112:243-54. [PMID: 24718307 DOI: 10.1160/th13-06-0517] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 03/07/2014] [Indexed: 11/05/2022]
Abstract
Tissue-type plasminogen activator (t-PA ) plays an important role in the removal of intravascular fibrin deposits and has several physiological roles and pathological activities in the brain. Its production by many other cell types suggests that t-PA has additional functions outside the vascular and central nervous system. Activity of t-PA is regulated at the level of its gene transcription, its mRNA stability and translation, its storage and regulated release, its interaction with cofactors that enhance its activity, its inhibition by inhibitors such as plasminogen activator inhibitor type 1 or neuroserpin, and its removal by clearance receptors. Gene transcription of t-PA is modulated by a large number of hormones, growth factors, cytokines or drugs and t-PA gene responses may be tissue-specific. The aim of this review is to summarise current knowledge on t-PA function and regulation of its pericellular activity, with an emphasis on regulation of its gene expression.
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Affiliation(s)
- E K O Kruithof
- Egbert K.O. Kruithof, Division of Angiology and Hemostasis, Department of internal medicine, University Hospital of Geneva and Faculty of Medicine of the University of Geneva, University Medical Center CMU 9094, 1 Rue Michel Servet, CH1211 Geneva 4, Switzerland, Tel.: +41 22 3795493 or +41 22 3795567, E-mail:
| | - S Dunoyer-Geindre
- Sylvie Dunoyer-Geindre, Division of Angiology and Hemostasis, Department of internal medicine, University Hospital of Geneva and Faculty of Medicine of the University of Geneva, University Medical Center CMU 9094, 1 Rue Michel Servet, CH1211 Geneva 4, Switzerland, Tel.: +41 22 3795493 or +41 22 3795567, E-mail:
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16
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Fletcher DJ, Brainard BM, Epstein K, Radcliffe R, Divers T. Therapeutic plasma concentrations of epsilon aminocaproic acid and tranexamic acid in horses. J Vet Intern Med 2013; 27:1589-95. [PMID: 24118238 DOI: 10.1111/jvim.12202] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/17/2013] [Accepted: 08/20/2013] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Antifibrinolytic drugs such as epsilon aminocaproic acid (EACA) and tranexamic acid (TEA) are used to treat various bleeding disorders in horses. Although horses are hypofibrinolytic compared to humans, dosing schemes have been derived from pharmacokinetic studies targeting plasma concentrations in humans. HYPOTHESIS/OBJECTIVES We hypothesized therapeutic plasma concentrations of antifibrinolytic drugs in horses would be significantly lower than in humans. Our objective was to use thromboleastography (TEG) and an in vitro model of hyperfibrinolysis to predict therapeutic concentrations of EACA and TEA in horses and humans. ANIMALS Citrated plasma collected from 24 random source clinically healthy research horses. Commercial pooled human citrated plasma with normal coagulation parameters was purchased. METHODS Minimum tissue plasminogen activator (tPA) concentration to induce complete fibrinolysis within 10 minutes was determined using serial dilutions of tPA in equine plasma. Results used to create an in vitro hyperfibrinolysis model with equine and human citrated plasma, and the minimum concentrations of EACA and TEA required to completely inhibit fibrinolysis for 30 minutes (estimated therapeutic concentrations) determined using serial dilutions of the drugs. RESULTS Estimated therapeutic concentrations of EACA and TEA were significantly lower in horses (5.82; 95% CI 3.77-7.86 μg/mL and 0.512; 95% CI 0.277-0.748 μg/mL) than in humans (113.2; 95% CI 95.8-130.6 μg/mL and 11.4; 95% CI 8.62-14.1 μg/mL). CONCLUSIONS AND CLINICAL IMPORTANCE Current dosing schemes for EACA and TEA in horses may be as much as 20× higher than necessary, potentially increasing cost of treatment and risk of adverse effects.
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Affiliation(s)
- D J Fletcher
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY
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17
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Din JN, Sarma J, Harding SA, Lyall K, Newby DE, Flapan AD. Effect of ω-3 fatty acid supplementation on endothelial function, endogenous fibrinolysis and platelet activation in patients with a previous myocardial infarction: a randomised controlled trial. BMJ Open 2013; 3:e003054. [PMID: 24071458 PMCID: PMC3787492 DOI: 10.1136/bmjopen-2013-003054] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 07/05/2013] [Accepted: 07/10/2013] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE The mechanisms through which ω-3 fatty acids reduce adverse cardiac events remain uncertain. We aimed to investigate the effect of ω-3 fatty acid supplementation on endothelial vasomotor function, endogenous fibrinolysis, and platelet and monocyte activation in patients with coronary heart disease. DESIGN Randomised, double-blind, placebo-controlled, cross-over trial. SETTING Academic cardiac centre. PARTICIPANTS 20 male patients with a previous myocardial infarction. INTERVENTION ω-3 Fatty acid supplementation (2 g/day for 6 weeks) versus olive oil placebo. OUTCOME MEASURES Peripheral blood was taken for analysis of platelet and monocyte activation, and forearm blood flow (FBF) was assessed in a subset of 12 patients during intrabrachial infusions of acetylcholine, substance P and sodium nitroprusside. Stimulated plasma tissue plasminogen activator (t-PA) concentrations were measured during substance P infusion. RESULTS All vasodilators caused dose-dependent increases in FBF (p<0.0001). ω-3 Fatty acid supplementation did not affect endothelium-dependent vasodilation with acetylcholine and substance P compared with placebo (p=0.5 and 0.9). Substance P caused a dose-dependent increase in plasma t-PA concentrations (p<0.0001), which was not affected by ω-3 fatty acid supplementation (p=0.9). ω-3 Fatty acids did not affect platelet-monocyte aggregation, platelet P-selectin or CD40L, or monocyte CD40. CONCLUSIONS We have demonstrated that dietary supplementation with ω-3 fatty acids does not affect endothelial vasomotor function, endothelial t-PA release, or platelet and monocyte activation in patients with coronary heart disease. Cardiac benefits conferred by ω-3 fatty acids in coronary heart disease are unlikely to be mediated through effects on these systems.
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Affiliation(s)
- Jehangir N Din
- Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh, UK
| | - Jaydeep Sarma
- North West Heart Centre, Wythenshawe Hospital, Manchester, UK
| | - Scott A Harding
- Department of Cardiology, Wellington Hospital, Wellington, New Zealand
| | - Karin Lyall
- Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh, UK
| | - David E Newby
- Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh, UK
| | - Andrew D Flapan
- Edinburgh Heart Centre, Royal Infirmary of Edinburgh, Edinburgh, UK
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18
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Unsolved issues in the management of high blood pressure in acute ischemic stroke. Int J Hypertens 2013; 2013:349782. [PMID: 23710338 PMCID: PMC3655558 DOI: 10.1155/2013/349782] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 04/03/2013] [Indexed: 11/17/2022] Open
Abstract
High blood pressure is common in acute stroke patients. Very high as well as very low blood pressure is associated with poor outcome. Spontaneous fall of blood pressure within the first few days after stroke was associated both with neurological improvement and impairment. Several randomized trials investigated the pharmacological reduction of blood pressure versus control. Most trials showed no significant difference in their primary outcome apart from the INWEST trial which found an increase of poor outcome when giving intravenous nimodipine. Nevertheless, useful information can be extracted from the published data to help guide the clinician's decision. Blood pressure should only be lowered when it is clearly elevated, and early after onset, reduction should be moderate but may be achieved rapidly. No clear recommendations can be given on the substances to use; however, care should be taken with intravenous calcium channel blockers and angiotensin receptor antagonists. Two ongoing randomized trials will help to solve the questions on blood pressure management in acute stroke.
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Fjellström O, Deinum J, Sjögren T, Johansson C, Geschwindner S, Nerme V, Legnehed A, McPheat J, Olsson K, Bodin C, Paunovic A, Gustafsson D. Characterization of a small molecule inhibitor of plasminogen activator inhibitor type 1 that accelerates the transition into the latent conformation. J Biol Chem 2012; 288:873-85. [PMID: 23155046 DOI: 10.1074/jbc.m112.371732] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A novel class of small molecule inhibitors for plasminogen activator inhibitor type 1 (PAI-1), represented by AZ3976, was identified in a high throughput screening campaign. AZ3976 displayed an IC(50) value of 26 μm in an enzymatic chromogenic assay. In a plasma clot lysis assay, the compound was active with an IC(50) of 16 μm. Surprisingly, AZ3976 did not bind to active PAI-1 but bound to latent PAI-1 with a K(D) of 0.29 μm at 35 °C and a binding stoichiometry of 0.94, as measured by isothermal calorimetry. Reversible binding was confirmed by surface plasmon resonance direct binding experiments. The x-ray structure of AZ3976 in complex with latent PAI-1 was determined at 2.4 Å resolution. The inhibitor was bound in the flexible joint region with the entrance to the cavity located between α-helix D and β-strand 2A. A set of surface plasmon resonance experiments revealed that AZ3976 inhibited PAI-1 by enhancing the latency transition of active PAI-1. Because AZ3976 only had measurable affinity for latent PAI-1, we propose that its mechanism of inhibition is based on binding to a small fraction in equilibrium with active PAI-1, a latent-like prelatent form, from which latent PAI-1 is then generated more rapidly. This mode of action, with induced accelerated latency transition of active PAI-1 may, together with supporting x-ray data, provide improved opportunities for small molecule drug design in the hunt for therapeutically useful PAI-1 inhibitors.
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Affiliation(s)
- Ola Fjellström
- Department of Medicinal Chemistry, AstraZeneca R&D Mölndal, S-431 83 Mölndal, Sweden.
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20
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Larsson P, Ulfhammer E, Magnusson M, Bergh N, Lunke S, El-Osta A, Medcalf RL, Svensson PA, Karlsson L, Jern S. Role of histone acetylation in the stimulatory effect of valproic acid on vascular endothelial tissue-type plasminogen activator expression. PLoS One 2012; 7:e31573. [PMID: 22363677 PMCID: PMC3282745 DOI: 10.1371/journal.pone.0031573] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 01/13/2012] [Indexed: 11/19/2022] Open
Abstract
Aims Stimulated release of tissue-type plasminogen activator (t-PA) is pivotal for an intravascular fibrinolytic response and protects the circulation from occluding thrombosis. Hence, an impaired t-PA production is associated with increased risk for atherothrombotic events. A pharmacological means to stimulate the production of this enzyme may thus be desirable. We investigated if the anti-epileptic drug valproic acid (VPA) is capable of enhancing t-PA expression in vitro in vascular endothelial cells, and further examined if its histone deacetylase (HDAC)-inhibitory activity is of importance for regulating t-PA expression. Methods and Results Human endothelial cells were exposed to valproic acid and t-PA mRNA and protein levels were quantified. Potential changes in histone acetylation status globally and at the t-PA promoter were examined by western blot and chromatin immunoprecipitation. Valproic acid dose-dependently stimulated t-PA mRNA and protein expression in endothelial cells reaching a 2–4-fold increase at clinically relevant concentrations and 10-fold increase at maximal concentrations. Transcription profiling analysis revealed that t-PA is selectively targeted by this agent. Augmented histone acetylation was detected at the t-PA transcription start site, and an attenuated VPA-response was observed with siRNA knock of HDAC3, HDAC5 and HDAC7. Conclusions Valproic acid induces t-PA expression in cultured endothelial cells, and this is associated with increased histone acetylation at the t-PA promoter. Given the apparent potency of valproic acid in stimulating t-PA expression in vitro this substance may be a candidate for pharmacological modulation of endogenous fibrinolysis in man.
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Affiliation(s)
- Pia Larsson
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Erik Ulfhammer
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mia Magnusson
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Bergh
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Sebastian Lunke
- Epigenetics in Human Health and Disease Laboratory, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, Victoria, Australia
| | - Assam El-Osta
- Epigenetics in Human Health and Disease Laboratory, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, Victoria, Australia
| | - Robert L. Medcalf
- Australian Centre for Blood Diseases, The Alfred Medical Research and Education Point, Monash University, Melbourne, Victoria, Australia
| | - Per-Arne Svensson
- Sahlgrenska Center for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lena Karlsson
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Sverker Jern
- The Wallenberg Laboratory for Cardiovascular Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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21
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van der Pals J, Götberg MI, Götberg M, Hultén LM, Magnusson M, Jern S, Erlinge D. Hypothermia in cardiogenic shock reduces systemic t-PA release. J Thromb Thrombolysis 2011; 32:72-81. [PMID: 21190125 DOI: 10.1007/s11239-010-0541-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Therapeutic hypothermia has been found to improve hemodynamic and metabolic parameters in cardiogenic shock. Tissue plasminogen activator (t-PA) is a pro-thrombolytic enzyme, which also possesses pro-inflammatory properties. Interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α) are pro-inflammatory cytokines; interleukin 10 (IL-10) and transforming growth factor beta 1 (TGF-β1) are anti-inflammatory cytokines. The aim of this experiment was to investigate the mechanism behind the protective effect of therapeutic hypothermia in cardiogenic shock. This was done by studying the effect of hypothermia on basal t-PA levels, peripheral t-PA release, and on the inflammatory response. Cardiogenic shock was induced by inflation of an angioplasty balloon in the proximal left anterior descending artery for 40 min in 16 pigs, followed by 110 min of reperfusion. The animals were randomized to hypothermia (33°C, n = 8), or normothermia (n = 8) at reperfusion. Hemodynamic parameters were continuously monitored. Plasma was sampled every 30 min for analysis of blood-gases and t-PA, and for analysis of inflammatory markers at baseline and at the end of the experiment. t-PA, IL-6 and TGF-β1 increased during cardiogenic shock. Apart from favourably affecting hemodynamic and metabolic variables, hypothermia was found to reduce basal arterial and venous t-PA levels, and to inhibit the release of t-PA from the peripheral vascular bed. Hypothermia did not alter the inflammatory response. In conclusion, mild hypothermia improves hemodynamic and metabolic parameters in cardiogenic shock. This is associated with a reduction in basal t-PA levels and t-PA release from the peripheral vascular bed, but not with an altered inflammatory response.
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Affiliation(s)
- Jesper van der Pals
- Department of Cardiology, Skåne University Hospital, Lund University, 221 85, Lund, Sweden
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22
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Fogari R, Zoppi A, Salvadeo SAT, Mugellini A, Lazzari P, Santoro T, Derosa G. Fibrinolysis and insulin sensitivity in imidapril and candesartan (FISIC study) recipients with hypertension. Hypertens Res 2010; 34:509-15. [DOI: 10.1038/hr.2010.260] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Matsumoto T, Takashima H, Nakae I, Yamane T, Hayashi H, Horie M. Angiotensin-Converting Enzyme Inhibition Augments Coronary Release of Tissue Plasminogen Activator in Women But Not in Men. Hypertension 2010; 56:364-8. [DOI: 10.1161/hypertensionaha.110.154278] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The renin-angiotensin system regulates the vascular fibrinolytic balance. In the human forearm vasculature, angiotensin-converting enzyme (ACE) inhibitors (ACE-Is) increase the release of t-PA through endogenous bradykinin. We tested the hypothesis that ACE inhibition and sex modulate the endogenous coronary release of tissue plasminogen activator (t-PA) in hypertensive patients. Seventy-three patients underwent diagnostic coronary angiography and had normal coronary angiograms. Thirty-three patients (21 men and 12 women) were treated with imidapril (5 mg/day) for 4 weeks (ACE-I group), and 40 (23 men and 17 women) were not treated with ACE-I (non–ACE-I group). All of the women were postmenopausal. Coronary blood flow in the left anterior descending artery was evaluated by measuring Doppler flow velocity. Net coronary t-PA release was determined as (coronary sinus−aorta gradient of t-PA)×(coronary blood flow)×[(100−hematocrit)/100]. Age, arterial pressure, heart rate, lipid levels, coronary flow, and the plasma level of t-PA at either aorta or coronary sinus were comparable among the 4 groups. In women, net t-PA release in the ACE-I group was significantly higher than that in the other groups (
P
<0.05; man non–ACE-I group: 1.4±2.6 ng/mL; woman non–ACE-I group: 1.4±3.1 ng/mL; man ACE-I group: −1.8±2.8 ng/mL; woman ACE-I group: 14.8±3.6 ng/mL). Correction for smoking status gave similar results. There was a significant negative correlation between serum ACE activity and coronary t-PA release in women (
r
=−0.38;
P
<0.05) but not in men. ACE inhibition increases coronary release of t-PA in women but not in men.
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Affiliation(s)
- Tetsuya Matsumoto
- From the Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Hiroyuki Takashima
- From the Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Ichiro Nakae
- From the Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Tetsunobu Yamane
- From the Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Hideki Hayashi
- From the Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Minoru Horie
- From the Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
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Robb AO, Mills NL, Din JN, Cameron S, Ludlam CA, Newby DE, Denison FC. Acute endothelial tissue plasminogen activator release in pregnancy. J Thromb Haemost 2009; 7:138-42. [PMID: 18983502 DOI: 10.1111/j.1538-7836.2008.03207.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Pregnancy is associated with marked changes in vascular physiology and an increased risk of thrombosis. The aim of the study was to assess the effect of pregnancy on the acute release of tissue plasminogen activator (t-PA) from the endothelium. METHODS AND RESULTS Ten primigravida pregnant women were recruited in the third trimester of pregnancy (week 36 +/- 1) and compared with 20 age-matched non-pregnant women (day 9.8 +/- 0.3 of menstrual cycle). Blood flow and plasma fibrinolytic factors were measured in both forearms by venous occlusion plethysmography and blood sampling, respectively, during unilateral brachial artery infusions of bradykinin (100-1000 pmol min(-1)). Pregnant women had higher plasma plasminogen activator inhibitor type 1 (PAI-1) antigen concentrations (77.1 +/- 12.4 vs. 21.5 +/- 9.8 ng mL(-1); P = 0.004) that resulted in lower basal t-PA/PAI-1 ratios (0.2 +/- 0.1 vs. 0.6 +/- 0.1; P = 0.02) and plasma t-PA activity concentrations (0.17 +/- 0.02 vs. 0.58 +/- 0.06 IU mL(-1); P < 0.0004). In both groups, bradykinin caused dose-dependent increases in blood flow and local release of plasma t-PA antigen and activity (P < 0.005 for all). Both the plasma t-PA/PAI-1 ratios and the net release of active t-PA were markedly reduced in pregnant women (P < 0.05 for both). Area under the curve for net active t-PA release was reduced by 36%. CONCLUSIONS Pregnancy is associated with major perturbations of endogenous fibrinolytic capacity with an overwhelming increase in plasma PAI-1 concentrations and an inadequate release of active t-PA. These prothrombotic effects may, in part, explain the increased risk of arterial and venous thrombosis in pregnant women.
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Affiliation(s)
- A O Robb
- Centre for Reproductive Biology, University of Edinburgh, Edinburgh, UK
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Osterlund B, Jern S, Jern C, Seeman-Lodding H, Ostman M, Johansson G, Biber B. Impaired myocardial t-PA release in patients with coronary artery disease. Acta Anaesthesiol Scand 2008; 52:1375-84. [PMID: 19025531 DOI: 10.1111/j.1399-6576.2008.01741.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS Myocardial ischemia remains a significant perioperative complication in coronary artery disease (CAD) patients. We hypothesized that noxious stimuli during major surgery are associated with an acute release of tissue-type plasminogen activator (t-PA) into the coronary circulation, and that this response is reduced by CAD. METHODS AND RESULTS Two patient groups, with (n=14) and without (n=8) CAD, were studied during the initial phase of heart surgery. After retrograde great cardiac vein catheterizations during closed-chest conditions, coronary arterial-venous concentration gradients of t-PA and plasminogen activator inhibitor type-1 (PAI-1) were measured together with coronary blood flow measurements, allowing derivation of coronary net release rates. Pre-surgery atrial pacing, performed to evaluate the influence of increases in heart rate (+ 40 beats/min) and coronary blood flow (+ 80 ml/min), did not significantly alter coronary net release of t-PA or PAI-1 in either patient group. Sternotomy induced a prominent increase in coronary net release of both total and active t-PA in the non-CAD group. This response was considerably reduced in the CAD group. CONCLUSIONS This study provides the first analysis of coronary t-PA release during major surgery and demonstrates a deficient local endothelial t-PA release in patients with CAD. This suggests a reduced local fibrinolytic capacity in CAD patients, which may explain the increased risk for coronary thrombosis in this patient group.
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Affiliation(s)
- B Osterlund
- Surgical and Perioperative Science, Anesthesiology and Intensive Care, Umeå University, Umeå, Sweden.
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27
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Brogren H, Sihlbom C, Wallmark K, Lönn M, Deinum J, Karlsson L, Jern S. Heterogeneous glycosylation patterns of human PAI-1 may reveal its cellular origin. Thromb Res 2008; 122:271-81. [PMID: 18508114 DOI: 10.1016/j.thromres.2008.04.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 04/02/2008] [Accepted: 04/02/2008] [Indexed: 11/28/2022]
Abstract
The main inhibitor of intravascular fibrinolysis is plasminogen activator inhibitor 1 (PAI-1) which binds to and irreversibly inhibits tissue plasminogen activator (tPA). PAI-1 is present in blood, both in platelets and in plasma, and PAI-1 levels are associated with risk of atherothrombosis. Several tissues express PAI-1 but the source of plasma PAI-1 is not known. We recently found that platelets can de novo synthesize PAI-1 and the amount synthesized in vitro in 24 hours is 35-fold higher than required to maintain normal plasma levels. Recombinant human PAI-1 expressed in different cell types or secreted naturally by human cell lines, exhibit heterogeneous glycosylation patterns. The aim of this study was to investigate the hypothesis that platelets might be the source of plasma PAI-1 and that the cellular source of PAI-1 can be determined by its tissue-specific glycosylation pattern. PAI-1 was isolated from platelets, macrophages, endothelial cells, adipose tissue, as well as plasma from lean and obese subjects. The glycosylation was analyzed by nanoLC-MS/MS. PAI-1 isolated from cell lysates and conditioned media from macrophages, endothelial cells, and adipose tissue expressed heterogeneous glycosylation patterns. By contrast, no glycans were detected on PAI-1 isolated from plasma or platelets from healthy lean individuals. Hence, our data suggest that platelets may be the main source of plasma PAI-1 in lean individuals. Interestingly, plasma PAI-1 from obese subjects had a glycan composition similar to that of adipose tissue suggesting that obese subjects with elevated PAI-1 levels may have a major contribution from other tissues.
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Affiliation(s)
- Helén Brogren
- Clinical Experimental Research Laboratory, Sahlgrenska University Hospital/Ostra, Institute of Medicine, University of Gothenburg, Gothenburg
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Giannarelli C, Virdis A, De Negri F, Duranti E, Magagna A, Ghiadoni L, Salvetti A, Taddei S. Tissue-Type Plasminogen Activator Release in Healthy Subjects and Hypertensive Patients. Hypertension 2008; 52:314-21. [DOI: 10.1161/hypertensionaha.108.111559] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Chiara Giannarelli
- From the Department of Internal Medicine, University of Pisa, Pisa, Italy
| | - Agostino Virdis
- From the Department of Internal Medicine, University of Pisa, Pisa, Italy
| | | | - Emiliano Duranti
- From the Department of Internal Medicine, University of Pisa, Pisa, Italy
| | - Armando Magagna
- From the Department of Internal Medicine, University of Pisa, Pisa, Italy
| | - Lorenzo Ghiadoni
- From the Department of Internal Medicine, University of Pisa, Pisa, Italy
| | - Antonio Salvetti
- From the Department of Internal Medicine, University of Pisa, Pisa, Italy
| | - Stefano Taddei
- From the Department of Internal Medicine, University of Pisa, Pisa, Italy
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29
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Larsson P, Ulfhammer E, Karlsson L, Bokarewa M, Wåhlander K, Jern S. Effects of IL-1beta and IL-6 on tissue-type plasminogen activator expression in vascular endothelial cells. Thromb Res 2008; 123:342-51. [PMID: 18502475 DOI: 10.1016/j.thromres.2008.03.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 02/22/2008] [Accepted: 03/04/2008] [Indexed: 11/30/2022]
Abstract
INTRODUCTION The increased risk of thrombus formation in inflammatory conditions is generally considered to be due to the pro-coagulant effect of inflammatory cytokines. However, cytokines may also decrease the expression of the key fibrinolytic enzyme tissue-type plasminogen activator (t-PA) causing a reduced clearance of emerging intravascular thrombi. This study investigated the effects of the inflammatory cytokines interleukin (IL)-1beta and IL-6 on t-PA gene and protein expression, and elucidated by which signaling mechanisms the effects are mediated. MATERIALS AND METHODS Cultured human umbilical vein endothelial cells (HUVEC) were exposed to recombinant IL-1beta or IL-6. t-PA mRNA was quantified by real-time RT-PCR and t-PA antigen by ELISA. To clarify signaling mechanisms, selective inhibitors of major cytokine-activated signaling pathways were used. Interactions of nuclear proteins with potential t-PA gene regulatory elements were studied by gel shift assays. RESULTS Already at low concentrations, IL-1beta caused a distinct suppression of t-PA transcript and protein levels, mediated primarily by NF-kappaB signaling. This cytokine also increased binding of NF-kappaB subunits to a t-PA specific kappaB element. IL-6 stimulation per se did not affect t-PA mRNA or protein levels whereas soluble IL-6 receptor, in the presence of endogenous IL-6, suppressed t-PA expression. CONCLUSIONS We conclude that the proinflammatory cytokine IL-1beta impairs fibrinolytic capacity in vascular endothelial cells by an NF-kappaB dependent suppression of t-PA expression. In contrast, an effect of IL-6 on t-PA expression could not be detected, probably due to lack of IL-6 receptor expression on HUVEC.
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Affiliation(s)
- Pia Larsson
- Department of Emergency and Cardiovascular Medicine, Sahlgrenska University Hospital/Ostra, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
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30
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Kaehler J, Koeke K, Karstens M, Schneppenheim R, Meinertz T, Heitzer T. Impaired capacity for acute endogenous fibrinolysis in smokers is restored by ascorbic acid. Free Radic Biol Med 2008; 44:315-21. [PMID: 18215739 DOI: 10.1016/j.freeradbiomed.2007.08.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 08/02/2007] [Accepted: 08/25/2007] [Indexed: 11/26/2022]
Abstract
Elevated levels of fibrinogen, C-reactive protein, and increased platelet aggregation are known to be increased by cigarette smoking, but the underlying mechanisms of the prothrombotic state in smokers are not completely understood. Since cigarette smoke contains several oxidants, we investigated the effect of the antioxidant ascorbic acid on stimulated fibrinolytic activity in smokers. Long-term heavy smokers and nonsmokers were studied by measurement of forearm blood flow; coinfusion of ascorbic acid was used to reduce oxidative stress. Concentrations of t-PA antigen and activity, of plasminogen activator inhibitor-1 (PAI-1) antigen and activity, and of C-reactive protein were determined by enzyme-linked immunosorbent assays and photometry, respectively. While dose-response curves of forearm blood flow elicited by substance P were not altered by the coadministration of ascorbic acid in nonsmokers, impaired flow in smokers markedly increased, P=0.003. Also, selectively in smokers, the maximal stimulated net release of t-PA antigen and of t-PA activity increased when ascorbic acid was infused simultaneously, P=0.002. In smokers CRP concentrations correlated significantly with the effect of ascorbic acid on maximal t-PA activity release, P<0.0001. Our data demonstrate that the endothelial capacity to acutely release t-PA is significantly reduced in heavy smokers and can be reversed by ascorbic acid. This association is particularly pronounced in smokers with high serum levels of C-reactive protein, suggesting that smoking-induced inflammation impairs fibrinolysis in these patients.
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Affiliation(s)
- Jan Kaehler
- Department of Cardiology/Angiology, University Heart Center, University Hospital Hamburg, Martinistrasse 52, 20246 Hamburg, Germany
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31
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Haus E. Chronobiology of hemostasis and inferences for the chronotherapy of coagulation disorders and thrombosis prevention. Adv Drug Deliv Rev 2007; 59:966-84. [PMID: 17822804 DOI: 10.1016/j.addr.2006.11.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Accepted: 11/05/2006] [Indexed: 01/09/2023]
Abstract
The hemostatic system in its multiple components displays an intricate organization in time which is characterized by circadian (approximately 24-hour), circaseptan (approximately 7-day), menstrual (approximately monthly), and circannual (approximately yearly) bioperiodicities. The interaction of the rhythms of the variables participating in hemostasis determine transient risk states of thromboembolic events, including myocardial infarction and stroke, and of hemorrhage and hemorrhagic events, each with a unique timing. The circadian staging of the rhythms in vascular, cellular, and coagulation factors that favors blood coagulation and thrombosis coincides with the daily minimum in fibrinolytic activity; as a result there is elevated risk in the morning of acute myocardial infarction and stroke. Similar hemostatic rhythms may determine the epidemiology of thromboembolic and hemorrhagic events during the week, month and year. This article focuses on the large-amplitude circadian rhythms operative in the hemostatic system. Their implication for preventive and curative pharmacotherapy of hemostatic disorders is presented, with discussion of related problems.
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Affiliation(s)
- Erhard Haus
- University of Minnesota, HealthPartners Medical Group, Regions Hospital, St. Paul 55101, USA.
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32
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Vergouwen MDI, Vermeulen M, de Haan RJ, Levi M, Roos YB. Dihydropyridine calcium antagonists increase fibrinolytic activity: a systematic review. J Cereb Blood Flow Metab 2007; 27:1293-308. [PMID: 17191079 DOI: 10.1038/sj.jcbfm.9600431] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Calcium antagonists have been shown to be superior over other antihypertensive drugs to prevent stroke. Because this cannot be fully attributed to blood pressure lowering effects, other mechanisms seem to play a role. Previously we found in patients with subarachnoid hemorrhage that nimodipine enhances fibrinolytic activity. The purpose of this systematic review was to investigate the fibrinolytic effect of calcium antagonists in general, especially in patients with hypertension. We systematically studied the entire PUBMED and EMBASE database with the search terms 'calcium antagonist' combined with 'fibrinolysis', '(euglobulin) clot lysis time' (ECLT), 'tissue plasminogen activator' (tPA), or 'plasminogen activator inhibitor' (PAI). Twenty-six prospective studies were identified and 22 manuscripts were included (802 investigated individuals). The results show that calcium antagonists significantly increase fibrinolysis as shown by a reduction of the ECLT standardized mean differences (SMD) -0.58 (95% confidence interval (CI) -1.05 to -0.11)) and an increase of tPA activity (SMD 0.73 (95% CI 0.25 to 1.21)). This increase of fibrinolysis is apparently caused by an increase of the tPA antigen level (SMD 0.16 (95% CI -0.05 to 0.37)) and a decrease of the plasminogen activator inhibitor-1 antigen antigen (SMD -0.36 (95% CI -0.74 to 0.02)). A sensitivity analysis showed that dihydropyridines, but not phenylalkylamines, exert a fibrinolytic effect. This fibrinolytic effect is not only seen in patients with subarachnoid hemorrhage but also in hypertensive patients. In conclusions, calcium antagonists increase fibrinolytic activity. This may add to the beneficial pharmacological effect of calcium antagonists to prevent ischemic events in patients with hypertension and subarachnoid hemorrhage.
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Affiliation(s)
- Mervyn D I Vergouwen
- Department of Neurology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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33
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Jood K, Jern C, Blomstrand C, Jern S, Hrafnkelsdóttir T. Local tissue-type plasminogen activator release in patients with ischemic stroke. J Thromb Haemost 2007; 5:1320-3. [PMID: 17403094 DOI: 10.1111/j.1538-7836.2007.02558.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Robinson SD, Ludlam CA, Boon NA, Newby DE. Endothelial fibrinolytic capacity predicts future adverse cardiovascular events in patients with coronary heart disease. Arterioscler Thromb Vasc Biol 2007; 27:1651-6. [PMID: 17463331 DOI: 10.1161/atvbaha.107.143248] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The endothelium-derived fibrinolytic factor tissue plasminogen activator (t-PA) is a major determinant of vessel patency after coronary plaque rupture and thrombosis. We assessed whether endothelial fibrinolytic capacity predicts atherothrombotic events in patients with coronary heart disease. METHODS AND RESULTS Plasma t-PA and plasminogen activator inhibitor (PAI)-1 concentrations were measured during intrabrachial substance P infusion in 98 patients with angiographically proven stable coronary heart disease. Forearm blood flow was measured during infusion of substance P and sodium nitroprusside. Cardiovascular events (cardiovascular death, myocardial infarction [MI], ischemic stroke [CVA], and emergency hospitalization for unstable angina) were determined during 42 months of follow-up. Patients experiencing a cardiovascular event (n=19) had similar baseline characteristics to those free of events. Substance P caused a dose-dependent increase in plasma t-PA concentrations (P<0.001). However, net t-PA release was 72% lower in the patients who experienced death, MI, or CVA, and 48% lower in those who suffered death, MI, CVA or hospitalization for unstable angina (P<0.05). Major adverse cardiovascular events were most frequent in those with the lowest fibrinolytic capacity (P=0.03 for trend); patients with the lowest quartile of t-PA release had the highest rate of adverse events (P=0.01). CONCLUSION Endothelial fibrinolytic capacity, as measured by stimulated t-PA release, predicts the future risk of adverse cardiovascular events in patients with coronary heart disease. We suggest that endothelial fibrinolytic capacity is a powerful novel determinant of cardiovascular risk.
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Affiliation(s)
- Simon D Robinson
- Centre for Cardiovascular Sciences, University of Edinburgh, Royal Infirmary of Edinburgh, 49 Little France Crescent, Edinburgh, Scotland, EH16 4SB, UK.
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35
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Olivecrona GK, Götberg M, Harnek J, Jacobson KA, Jern S, Erlinge D. The ADP receptor P2Y(1) mediates t-PA release in pigs during cardiac ischemia. J Thromb Thrombolysis 2007; 24:115-22. [PMID: 17294140 PMCID: PMC4609030 DOI: 10.1007/s11239-007-0010-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 01/12/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND The endothelial ADP receptor P2Y(1) is responsible for a large part of the reactive hyperemia following cardiac ischemia. Tissue plasminogen activator (t-PA) increases during reactive hyperemia. We postulated that the release of t-PA during reactive hyperemia could be mitigated through blocking the coronary endothelial P2Y(1) receptor. METHODS t-PA was measured in peripheral arterial blood and locally in the venous blood from the coronary sinus in a porcine model. The stable ADP analogue 2-MeSADP (10(-5) M), alone or as co-infusion with a selective P2Y(1) receptor blocker, MRS2179 (10(-3) M) was locally delivered in the left anterior descending artery through the tip of a coronary angioplasty balloon. In separate pigs the coronary artery was occluded with the balloon for 10 min. During the first and tenth minute of coronary ischemia, 2.5 ml of MRS2179 (10(-3) M) was delivered distal to the occlusion in 8 pigs, 10 pigs were used as controls. RESULTS 2-MeSADP increased levels of t-PA in the coronary sinus, which could be significantly inhibited by co-infusion with MRS2179. During cardiac ischemia and reperfusion, t-PA increased significantly, an effect that could be significantly inhibited by MRS2179. CONCLUSIONS Intra coronary administered MRS2179, a selective P2Y(1) receptor blocker, significantly reduces the increased levels of t-PA caused by both 2-MeSADP and cardiac ischemia in coronary arteries. Thus, ADP acting on the endothelial P2Y(1) receptor may mediate release of t-PA during ischemia and post-ischemic hyperemia, an effect that may counteract some of the platelet activating effects of ADP. Abbreviated Abstract We postulated that the release of t-PA during post ischemic reactive hyperemia could be mitigated through blocking the coronary endothelial P2Y(1) receptor in a porcine model. The ADP analogue 2-MeSADP (10(-5) M), alone or as co-infusion with a the P2Y(1) receptor blocker, MRS2179 (10(-3) M) was locally delivered in the left anterior descending artery. In separate pigs the coronary artery was occluded for ten min. During the first and tenth min of coronary ischemia, 2.5 ml of MRS2179 (10(-3) M) was delivered distal to the occlusion. t-PA was measured in peripheral arterial blood and also from the Coronary Sinus. We found that levels of t-PA in the blood from the coronary Sinus increased during infusion with 2-MeSADP as well as during ischemia and reperfusion. In pigs treated with MRS2179 levels of t-PA in the Coronary Sinus were significantly reduced during both coinfusion with 2-MeSADP and during ischemia/reperfusion. Thus, ADP acting on the endothelial P2Y(1) M receptor may mediate release of t-PA during ischemia and post-ischemic hyperemia, an effect that may counteract some of the platelet activating effects of ADP.
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Affiliation(s)
- Goran K Olivecrona
- Department of Cardiology, Lund University Hospital, Lund University, Lund 22185, Sweden
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36
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Ridderstråle W, Ulfhammer E, Jern S, Hrafnkelsdóttir T. Impaired Capacity for Stimulated Fibrinolysis in Primary Hypertension Is Restored by Antihypertensive Therapy. Hypertension 2006; 47:686-91. [PMID: 16520399 DOI: 10.1161/01.hyp.0000210540.35296.62] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The increased risk for myocardial infarction and ischemic stroke in primary hypertension suggests that the condition is associated with prothrombotic mechanisms. We have shown that patients with hypertension have an impaired capacity for acute endothelial tissue-type plasminogen activator (t-PA) release, an important local protective response to prevent formation of intravascular thrombi. The aim of the present study was to investigate whether this impairment could be restored by the lowering of blood pressure. The capacity for acute t-PA release in response to intraarterial infusion of substance P at 8 pmol/min was investigated in a perfused-forearm study in 20 hypertensive patients (12 men and 8 women). Studies were performed when patients were untreated and after 8 weeks of randomized treatment with lisinopril or felodipine that lowered blood pressure by 26/10 and 24/12 mm Hg, respectively. The t-PA release response increased significantly with treatment (ANOVA,
P
=0.0001), with a similar effect in the 2 treatment groups. The peak release of t-PA increased from 257 (58) to 445 (77) ng/min×L/tissue
−1
(
t
test,
P
=0.02). Also, treatment shortened the average time to peak secretion from 6.7 (1.4) to 2.7 (0.3) min (
t
test,
P
=0.01). In 6 patients with a delayed secretory peak (9 minutes or later), treatment normalized the response (χ
2
test,
P
=0.008). Antihypertensive therapy restores the capacity for acute t-PA release and improves the rapidity of the response in patients with primary hypertension. Similar responses with the 2 regimens suggest that the improvement is related to the blood pressure reduction as such. This effect may contribute to the thromboprotective effect of antihypertensive treatment.
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Affiliation(s)
- Wilhelm Ridderstråle
- Clinical Experimental Research Laboratory, Sahlgrenska University Hospital/Ostra, Institute of Medicine, Göteborg University, Göteborg, Sweden
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37
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Oliver JJ, Webb DJ, Newby DE. Stimulated Tissue Plasminogen Activator Release as a Marker of Endothelial Function in Humans. Arterioscler Thromb Vasc Biol 2005; 25:2470-9. [PMID: 16210566 DOI: 10.1161/01.atv.0000189309.05924.88] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The initiation, modulation, and resolution of thrombus associated with eroded or unstable coronary plaques are critically dependent on the efficacy of endogenous fibrinolysis. This is dependent on the cellular function of the surrounding endothelium and vascular wall. In particular, the acute release of tissue plasminogen activator from the endothelium makes an important contribution to the defense against intravascular thrombosis. Here, we describe the rationale and methodology for, and clinical relevance of, assessing acute endothelial tissue plasminogen activator release in humans. The investigation of endothelial fibrinolytic function has the potential to provide major new insights into the pathophysiology of cardiovascular disease, and to shape future therapeutic interventions.
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Affiliation(s)
- James J Oliver
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK.
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38
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Aspelin T, Eriksen M, Lindgaard AK, Lyberg T, Ilebekk A. Cardiac fibrinolytic capacity is markedly increased after brief periods of local myocardial ischemia, but declines following successive periods in anesthetized pigs. J Thromb Haemost 2005; 3:1947-54. [PMID: 16102101 DOI: 10.1111/j.1538-7836.2005.01514.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Fibrinolysis in blood is mainly reflected by the activities of tissue plasminogen activator (tPA) and of plasminogen activator inhibitor-1 (PAI-1). The effect of myocardial ischemia on their activities in the coronary circulation is, however, not established. OBJECTIVES With an improved experimental model, we therefore examined the effect of a brief period of myocardial ischemia on their activities. Furthermore, the consequences of repeated periods of ischemia, mimicking the situations in patients with unstable angina, were investigated. METHODS In six anesthetized pigs, we occluded the distal left anterior descending coronary artery (LAD) four times for 10 min with 40 min intervals and determined the activities of tPA and PAI-1 in arterial and coronary venous blood. By simultaneously recording LAD flow, we could estimate cardiac release of these factors at baseline conditions and during reperfusion. RESULTS Neither net cardiac release of PAI-1 nor alterations in plasma PAI-1 levels were demonstrated during the experiment. However, a significant net release of tPA activity of 10.4 +/- 3.2 IU mL(-1) (P < 0.005) was recorded during baseline conditions. During reperfusion following the first period of ischemia, the cardiac release of tPA activity increased to a peak of 103 +/- 30-fold baseline release, but declined progressively after repeated periods of ischemia. After the fourth period, tPA release did not exceed an estimated baseline accumulation during ischemia and early reperfusion. CONCLUSIONS In this porcine model, a substantial local increase in fibrinolytic capacity was observed after brief periods of ischemia, but declined subsequently by repeated periods of ischemia.
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Affiliation(s)
- T Aspelin
- Center for Clinical Research, Ullevaal University Hospital, Oslo, Norway.
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39
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Affiliation(s)
- J J Emeis
- Gaubius Laboratory, TNO Biomedical Research, Leiden, The Netherlands.
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40
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Hennan JK, Elokdah H, Leal M, Ji A, Friedrichs GS, Morgan GA, Swillo RE, Antrilli TM, Hreha A, Crandall DL. Evaluation of PAI-039 [{1-benzyl-5-[4-(trifluoromethoxy)phenyl]-1H-indol-3-yl}(oxo)acetic acid], a novel plasminogen activator inhibitor-1 inhibitor, in a canine model of coronary artery thrombosis. J Pharmacol Exp Ther 2005; 314:710-6. [PMID: 15860572 DOI: 10.1124/jpet.105.084129] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We tested a novel, orally active inhibitor of plasminogen activator inhibitor-1 (PAI-1) in a canine model of electrolytic injury. Dogs received by oral gavage either vehicle (control) or the PAI-1 inhibitor PAI-039 [{1-benzyl-5-[4-(trifluoromethoxy)phenyl]-1H-indol-3-yl}(oxo)acetic acid] (1, 3, and 10 mg/kg) and were subjected to electrolytic injury of the coronary artery. PAI-039 caused prolongation in time to coronary occlusion (control, 31.7 +/- 6.3 min; 3 mg/kg PAI-039, 66.0 +/- 6.4 min; 10 mg/kg, 56.7 +/- 7.4 min; n = 5-6; p < 0.05) and a reduced thrombus weight (control, 7.6 +/- 1.5 mg; 10 mg/kg PAI-039, 3.6 +/- 1.0 mg; p < 0.05). Although occlusive thrombosis was observed across all groups based upon the absence of measurable blood flow, a high incidence (>60%) of spontaneous reperfusion occurred only in those groups receiving PAI-039. Spontaneous reperfusion in the 10 mg/kg PAI-039 group accounted for total blood flow (area under the curve of coronary blood flow) of 99.6 +/- 11.7 ml after initial thrombotic occlusion (p < 0.05 compared with control). Plasma PAI-1 activity was reduced in all drug-treated groups (percentage of reduction in activity p < 0.05; 10 mg/kg PAI-039), whereas ADP-, 9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F(2alpha) (U46619)-, and collagen-induced platelet aggregation, as well as template bleeding and prothrombin time, remained unaffected by PAI-039. Ex vivo clot lysis analysis revealed normal clot formation but accelerated clot lysis in PAI-039-treated groups. The pharmacokinetic profile of PAI-039 indicated an oral bioavailability of 43 +/- 15.3% and a plasma half-life of 6.2 +/- 1.3 h. In conclusion, PAI-039 is an orally active prothrombolytic drug that inhibits PAI-1 and accelerates fibrinolysis while maintaining normal coagulation in a model of coronary occlusion.
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Affiliation(s)
- James K Hennan
- Cardiovascular and Metabolic Disease, Wyeth Research, N2252A, P.O. Box 42528, Philadelphia, PA 19101, USA.
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