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Eligini S, Munno M, Atlas D, Banfi C. N-acetylcysteine Amide AD4/NACA and Thioredoxin Mimetic Peptides Inhibit Platelet Aggregation and Protect against Oxidative Stress. Antioxidants (Basel) 2023; 12:1395. [PMID: 37507934 PMCID: PMC10376080 DOI: 10.3390/antiox12071395] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 06/28/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023] Open
Abstract
In the present study, we tested the effect of small-molecular-weight redox molecules on collagen-induced platelet aggregation. We used N-acetylcysteine amide (AD4/NACA), the amide form of N-acetylcysteine (NAC), a thiol antioxidant with improved lipophilicity and bioavailability compared to NAC, and the thioredoxin-mimetic (TXM) peptides, TXM-CB3, TXM-CB13, and TXM-CB30. All compounds significantly inhibited platelet aggregation induced by collagen, with TXM-peptides and AD4 being more effective than NAC. The levels of TxB2 and 12-HETE, the main metabolites derived from the cyclooxygenase and lipoxygenase pathways following platelet activation, were significantly reduced in the presence of AD4, TXM peptides, or NAC, when tested at the highest concentration (0.6 mM). The effects of AD4, TXM-peptides, and NAC were also tested on the clotting time (CT) of whole blood. TXM-CB3 and TXM-CB30 showed the greatest increase in CT. Furthermore, two representative compounds, TXM-CB3 and NAC, showed an increase in the anti-oxidant free sulfhydryl groups of plasma detected via Ellman's method, suggesting a contribution of plasma factors to the antiaggregating effects. Our results suggest that these small-molecular-weight redox peptides might become useful for the prevention and/or treatment of oxidative stress conditions associated with platelet activation.
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Affiliation(s)
- Sonia Eligini
- Centro Cardiologico Monzino IRCCS, Unit of Functional Proteomics, Metabolomics, and Network Analysis, 20138 Milan, Italy
| | - Marco Munno
- Centro Cardiologico Monzino IRCCS, Unit of Functional Proteomics, Metabolomics, and Network Analysis, 20138 Milan, Italy
| | - Daphne Atlas
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Cristina Banfi
- Centro Cardiologico Monzino IRCCS, Unit of Functional Proteomics, Metabolomics, and Network Analysis, 20138 Milan, Italy
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2
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Von Willebrand factor and the aortic valve: Concepts that are important in the transcatheter aortic valve replacement era. Thromb Res 2018; 170:20-27. [PMID: 30092557 DOI: 10.1016/j.thromres.2018.07.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 07/17/2018] [Accepted: 07/27/2018] [Indexed: 12/14/2022]
Abstract
Since the approval of the first transcatheter aortic valve replacement (TAVR) device in 2011, this technology has undergone substantial enhancements and exponential growth. However, valve thrombosis and residual paravalvular leaks (PVL) are among the challenges that require further investigation. Recently, monitoring von Willebrand factor (vWF) multimers has emerged as a tool to help evaluate the severity of PVL after TAVR. Following TAVR, vWF large multimers recovery have been documented. The role of large vWF multimers recovery and their interactions with platelets, and the endothelium have not been entirely elucidated. In this review, we discuss vWF synthesis and its role in aortic stenosis. We further provide an overview of the studies that investigated changes affecting vWF multimers following TAVR and the role of HMW vWF multimers monitoring in the determination of PVL severity. We also offer potential future directions for what will be fertile ground for research in this field.
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Li M, Hotaling NA, Ku DN, Forest CR. Microfluidic thrombosis under multiple shear rates and antiplatelet therapy doses. PLoS One 2014; 9:e82493. [PMID: 24404131 PMCID: PMC3880267 DOI: 10.1371/journal.pone.0082493] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 10/23/2013] [Indexed: 12/04/2022] Open
Abstract
The mainstay of treatment for thrombosis, the formation of occlusive platelet aggregates that often lead to heart attack and stroke, is antiplatelet therapy. Antiplatelet therapy dosing and resistance are poorly understood, leading to potential incorrect and ineffective dosing. Shear rate is also suspected to play a major role in thrombosis, but instrumentation to measure its influence has been limited by flow conditions, agonist use, and non-systematic and/or non-quantitative studies. In this work we measured occlusion times and thrombus detachment for a range of initial shear rates (500, 1500, 4000, and 10000 s(-1)) and therapy concentrations (0-2.4 µM for eptifibatide, 0-2 mM for acetyl-salicylic acid (ASA), 3.5-40 Units/L for heparin) using a microfluidic device. We also measured complete blood counts (CBC) and platelet activity using whole blood impedance aggregometry. Effects of shear rate and dose were analyzed using general linear models, logistic regressions, and Cox proportional hazards models. Shear rates have significant effects on thrombosis/dose-response curves for all tested therapies. ASA has little effect on high shear occlusion times, even at very high doses (up to 20 times the recommended dose). Under ASA therapy, thrombi formed at high shear rates were 4 times more prone to detachment compared to those formed under control conditions. Eptifibatide reduced occlusion when controlling for shear rate and its efficacy increased with dose concentration. In contrast, the hazard of occlusion from ASA was several orders of magnitude higher than that of eptifibatide. Our results show similar dose efficacy to our low shear measurements using whole blood aggregometry. This quantitative and statistically validated study of the effects of a wide range of shear rate and antiplatelet therapy doses on occlusive thrombosis contributes to more accurate understanding of thrombosis and to models for optimizing patient treatment.
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Affiliation(s)
- Melissa Li
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Nathan A Hotaling
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - David N Ku
- George W. Woodruff Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Craig R Forest
- George W. Woodruff Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
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Christensen RD, Sheffield MJ, Lambert DK, Baer VL. Effect of therapeutic hypothermia in neonates with hypoxic-ischemic encephalopathy on platelet function. Neonatology 2012; 101:91-4. [PMID: 21934334 DOI: 10.1159/000329818] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 05/31/2011] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Platelet dysfunction has been described in adults during hypothermia. We sought to determine whether it also occurs in neonates. METHODS We measured bleeding times and PFA-100 (platelet function analyzer) times in 10 neonates with hypoxic-ischemic encephalopathy during and after head cooling. RESULTS The 10 neonates were born at 38.2 ± 1.6 weeks' gestation (mean ± SD), with birth weights of 3,222 ± 746 g, pH 6.79 ± 0.17, base excess -25 ± 8, and 10-min Apgar 4 ± 2. Cooling was instituted 111 min (range: 66-180) after birth and continued 72 h. Bleeding times before cooling averaged 170 s (95% CI: 100-240). These lengthened during hypothermia, averaging 410 s (p = 0.000) and shortened after rewarming (p = 0.000). PFA-100 times were similar: prolongation during cooling and normalization after rewarming. Six neonates had clinical bleeding problems in the first 24 h of cooling, but were managed successfully, and no intracranial hemorrhages were identified. CONCLUSION Defective platelet plug formation occurs during therapeutic hypothermia of neonates in a manner similar to that described in adults. Platelet impairment can be severe, but rapidly improves after rewarming.
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Affiliation(s)
- Robert D Christensen
- Department of Women and Newborns, Intermountain Healthcare, Salt Lake City, Utah 84403, USA. rdchris4 @ ihc.com
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Correia-da-Silva M, Sousa E, Duarte B, Marques F, Carvalho F, Cunha-Ribeiro LM, Pinto MMM. Polysulfated xanthones: multipathway development of a new generation of dual anticoagulant/antiplatelet agents. J Med Chem 2011; 54:5373-84. [PMID: 21732671 DOI: 10.1021/jm2006589] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A multipathway strategy was used to evaluate the in vitro and in vivo antithrombotic effects of a new synthetic family of sulfated small molecules. Polysulfated xanthonosides showed highly effective anticoagulation effects in vitro, both in plasma (clotting times) and in whole human blood (thromboelastography), as well as in vivo (ip administration, mice). Physicochemical properties were assessed for mangiferin heptasulfate (7), which showed high solubility and stability in water and in human plasma and no putative hepatotoxicity in vivo. Mangiferin heptasulfate (7) was found to be a direct inhibitor of FXa, while persulfated 3,6-(O-β-glucopyranosyl)xanthone (13) acted as a dual inhibitor of FXa (directly and by antithrombin III activation). By impedance aggregometry, compounds 7 and 13 exhibited the antiplatelet effect by inhibition of both arachidonic acid and ADP-induced platelet aggregation. Dual anticoagulant/antiplatelet agents, such as sulfated xanthonosides 7 and 13, are expected to lead to a new therapeutic approach for the treatment of both venous and arterial thrombosis.
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Affiliation(s)
- Marta Correia-da-Silva
- Centro de Química Medicinal, Universidade do Porto (CEQUIMED-UP), Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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7
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Correia-da-Silva M, Sousa E, Duarte B, Marques F, Cunha-Ribeiro LM, Pinto MMM. Dual anticoagulant/antiplatelet persulfated small molecules. Eur J Med Chem 2011; 46:2347-58. [PMID: 21450376 DOI: 10.1016/j.ejmech.2011.03.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 03/03/2011] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
A new series of persulfated compounds was synthesized and assayed for in vitro anticoagulant and antiplatelet activities, which may be useful in the treatment of both venous and arterial thrombosis. Persulfation of polyphenolic components of wine, coumarins and other structurally diverse small molecules was achieved with triethylamine-sulphur trioxide adduct. The derivatives were highly effective in increasing the APTT, being trans-resveratrol 3-ß-D-glucopyranoside persulfate (15) the most potent (APTT2=1.5×10(-4) M), and were able to completely block the clotting process at the highest concentration. Compound 15 showed good stability in human plasma and anticoagulation effects in whole blood. trans-Resveratrol 3-ß-D-glucopyranoside persulfate (15) and a series of polysulfated oligoflavonoids (1-4) also exhibited antiplatelet activity by inhibition of arachidonic acid and ADP-induced platelet aggregation.
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Affiliation(s)
- Marta Correia-da-Silva
- Centro de Química Medicinal, Universidade do Porto (CEQUIMED-UP), Departamento de Ciências Químicas, Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, and Serviço de ImunoHemoterapia, Centro de Trombose, Hemostase e Biologia Vascular, Hospital de S. João, Rua Aníbal Cunha 164, 4050-047 Porto, Portugal
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8
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Tsou MY. Evaluation of the platelet function analyzer (PFA-100) vs. the thromboelastogram (TEG) in the clinical setting. ACTA ANAESTHESIOLOGICA TAIWANICA : OFFICIAL JOURNAL OF THE TAIWAN SOCIETY OF ANESTHESIOLOGISTS 2009; 47:107-109. [PMID: 19762299 DOI: 10.1016/s1875-4597(09)60035-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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9
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DUNCAN EM, BONAR R, RODGERS SE, FAVALORO EJ, MARSDEN K. Methodology and outcomes of platelet aggregation testing in Australia, New Zealand and the Asia-Pacific region: results of a survey from the Royal College of Pathologists of Australasia Haematology Quality Assurance Program. Int J Lab Hematol 2009; 31:398-406. [DOI: 10.1111/j.1751-553x.2008.01051.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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García Cubero M, Rodríguez Morales D, Burgoa Alcalaya B. Resistencia al ácido acetilsalicílico y sus repercusiones clínicas. Semergen 2008. [DOI: 10.1016/s1138-3593(08)71890-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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van Werkum JW, Hackeng CM, Smit JJJ, van’t Hof AWJ, Verheugt FWA, ten Berg JM. Monitoring antiplatelet therapy with point-of-care platelet function assays: a review of the evidence. Future Cardiol 2008; 4:33-55. [DOI: 10.2217/14796678.4.1.33] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Multiple studies have demonstrated that subgroups of patients receiving combination therapy with aspirin and clopidogrel fail to produce the anticipated antiplatelet effect, and various terms such as ‘aspirin resistance’, ‘clopidogrel resistance’, ‘heightened post-treatment platelet reactivity’ and ‘residual platelet reactivity’ have been introduced in the medical literature. Light transmittance aggregometry is generally considered to be the gold standard for determining platelet function, but its relevance to in vivo platelet function is questionable and the logistical demands of the method make it impossible to use in daily practice. The introduction of several point-of-care platelet function assays may be the key to the widespread clinical use of platelet function testing and may identify patients who are at risk for the occurrence of adverse cardiac events. In the present paper, we discuss the current commercially available methods of assaying platelet function, including their advantages and limitations and whether they have been shown to correlate with clinical outcomes.
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Affiliation(s)
- Jochem W van Werkum
- St Antonius Center for Platelet Function Research, Koekoekslaan 1, 3435 CM Nieuwegein, The Netherlands
| | - Christian M Hackeng
- St Antonius Center for Platelet Function Research, Koekoekslaan 1, 3435 CM Nieuwegein, The Netherlands
| | - Jaap-Jan J Smit
- Isala Klinieken, Department of Cardiology, Zwolle Groot Wezenland 20, 8011 JW Zwolle, The Netherlands
| | - Arnoud WJ van’t Hof
- Isala Klinieken, Department of Cardiology, Zwolle Groot Wezenland 20, 8011 JW Zwolle, The Netherlands
| | - Freek WA Verheugt
- University Medical Center St Radboud, Department of Cardiology, PO Box 9101, Nijmegen, The Netherlands
| | - Jurriën M ten Berg
- St Antonius Center for Platelet Function Research, Koekoekslaan 1, 3435 CM Nieuwegein, The Netherlands
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12
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Ying CLA, Tsang SF, Ng KFJ. The potential use of desmopressin to correct hypothermia-induced impairment of primary haemostasis—An in vitro study using PFA-100®. Resuscitation 2008; 76:129-33. [PMID: 17714852 DOI: 10.1016/j.resuscitation.2007.07.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 06/30/2007] [Accepted: 07/05/2007] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Mild hypothermia (32-35 degrees C) impairs primary haemostasis and coagulation. Correction of these haemostatic impairments by rewarming alone may not be possible or desirable, particularly in major trauma, neuroanaesthesia and in critically ill patients. Pharmacological treatment of these impairments, if available, may be a useful alternative. Desmopressin has been used to treat various congenital and acquired platelet disorders, but its effects on hypothermia-induced impairment of primary haemostasis is not known. This study aims to investigate the in vitro effects of desmopressin on hypothermia-induced impairment of primary haemostasis using PFA-100 platelet function analyzer. METHODS Whole blood was collected from 20 healthy volunteers, divided into 2.7 ml aliquots and some incubated at 32 degrees C, and others at 37 degrees C as control. Three log doses of desmopressin (0.01, 0.1 or 1 nM) were added to aliquots at 32 degrees C, and saline was added to controls at both 32 and 37 degrees C, all in 0.1 ml volume. After incubating for 30 min, closure times (CT) was measured by PFA-100 using both collagen/epinephrine (adrenaline) (Col/EPI) and collagen/adenosine-5'-diphosphate (Col/ADP) cartridges. RESULTS CT was prolonged by 30.9% (Col/EPI) and 18.8% (Col/ADP) at 32 degrees C, respectively, compared to 37 degrees C (P<0.001). All the three doses of desmopressin significantly, but incompletely corrected CT prolongation due to hypothermia (P<0.002). CONCLUSION Desmopressin partially reverses hypothermia-induced impairment of primary haemostasis in vitro, and may be potentially useful in improving haemostasis in hypothermic patients with bleeding where immediate rewarming is difficult or undesirable.
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Affiliation(s)
- Chee L A Ying
- Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Room 424, Block K, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong, China
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13
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Gaál T, Halmay D, Kocsis R, Abonyi-Tóth Z. Evaluation of the effect of ketoprofen and carprofen on platelet function in dogs studied by PFA-100 point-of-care analyser. Acta Vet Hung 2007; 55:287-94. [PMID: 17867455 DOI: 10.1556/avet.55.2007.3.2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The effect of two nonsteroidal anti-inflammatory drugs (carprofen and ketoprofen) on platelet adhesion and aggregation functions was evaluated by the PFA-100 analyser (Dade-Behring, CA, U.S.A.) using its collagen-adenosine diphosphate (ADP) and collagen-epinephrine (EPI) cartridges. The function of platelets was evaluated in 55 healthy dogs, in 7 dogs treated with ketoprofen and in 31 dogs treated with carprofen in a therapeutic dose for minimum 5 days. The therapeutic doses of carprofen had no effect on the closure time of PFA-100 (which is the marker of platelet function) but ketoprofen caused a significant increase when using collagen-EPI stimulation The closure times for both the healthy (control) and the treated dogs using EPI cartridges were often longer than the upper default cut-off point (300 sec) of the device. The PFA-100 analyser with collagen-ADP cartridges could be a useful tool for veterinary applications including the evaluation of platelet aggregation in dogs treated with NSAIDs. The upper cut-off point of PFA-100 might be extended.
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Affiliation(s)
- T Gaál
- Department of Internal Medicine Faculty of Veterinary Science, Szent István University, H-1078 Budapest, István u. 2, Hungary.
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Abstract
Platelets play a central role in hemostasis. Consequently, they lie at the heart of many inherited and acquired bleeding disorders and thrombotic events. The diagnosis of these disorders and monitoring of antiplatelet therapy require a thorough understanding of tests that measure platelet quantity and function. This article outlines basic concepts of platelet physiology and describes the tests that are commonly used in the clinical assessment of platelet function.
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Affiliation(s)
- Adam Seegmiller
- Department of Pathology, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9073, USA
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15
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The Platelet Function Analyzer (PFA)-100. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50790-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Stegnar M, Božič M, Dolenc MS, Anderluh PŠ, Kikelj D. Utility of PFA-100® closure time vs. optical aggregometry in assessing the efficacy of platelet membrane glycoprotein IIb/IIIa antagonists in vitro. ACTA ACUST UNITED AC 2007; 45:1542-8. [DOI: 10.1515/cclm.2007.318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractClin Chem Lab Med 2007;45:1542–8.
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Lau WC, Gurbel PA. Antiplatelet Drug Resistance and Drug-Drug Interactions: Role of Cytochrome P450 3A4. Pharm Res 2006; 23:2691-708. [PMID: 17061171 DOI: 10.1007/s11095-006-9084-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Accepted: 06/06/2006] [Indexed: 12/25/2022]
Abstract
Antiplatelet therapy provided pivotal advances in the treatment of cardiovascular disease. Aspirin and thienopyridine, clopidogrel, is currently the treatment of choice in acute coronary syndromes and the prevention of thrombosis after coronary stent implantation. Despite the efficacy of this dual antiplatelet therapy in reduction of adverse coronary events in patients with acute coronary syndromes, complications persist in a subgroup of these patients. Emerging causes of aspirin and clopidogrel resistance may translate to increase risk for recurrent myocardial infarction, stroke, or cardiac related mortality. However, the mechanism of antiplatelet drug resistance remains incompletely characterized, and a sensitive and specific assay of aspirin and clopidogrel effect that reliably predicts treatment failure has not emerged. To date, evidence supporting antiplatelet drug resistance are pharmacokinetic response variability, drug-drug interaction through competitive inhibition a specific enzymatic pathway, genetic variability, and variability in the induction of enzymatic pathway in metabolic activation of prodrugs, like clopidogrel. Further investigation or guidelines are needed to optimize antiplatelet treatment strategies to identify and treat patients resistant to aspirin and/or clopidogrel.
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Affiliation(s)
- Wei C Lau
- Medical Director Cardiovascular Center Operating Rooms, Cardiovascular Anesthesiology, University of Michigan Health System, Ann Arbor, Michigan, USA.
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Williams MS, Ng'alla LS. Heparin therapy leads to platelet activation and prolongation of PFA-100 closure time. J Cardiovasc Pharmacol Ther 2006; 10:273-80. [PMID: 16382263 DOI: 10.1177/107424840501000407] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Heparin is used in the treatment of venous and arterial thromboembolic events, including unstable angina. Once unfractionated heparin is discontinued during the acute phase of unstable angina, it has been demonstrated that the disease process may be reactivated within hours. It is hypothesized that this reactivation may be a result of direct platelet activation by heparin that can linger even after the drug itself has been stopped. Prior studies have shown that heparin can either increase or decrease platelet activation. More recent studies have also shown conflicting effects of unfractionated heparin on PFA-100 testing. METHODS We studied the in-vitro effects of unfractionated heparin on platelet function and PFA-100 testing. Unfractionated heparin was incubated with whole blood taken from 18 healthy volunteers. Platelet activation and aggregation was assessed with and without the presence of heparin. RESULTS Platelet aggregation and activation were increased in the presence of heparin. Unfractionated heparin also significantly prolonged collagen/adenosine diphosphate closure time but did not affect collagen/epinephrine closure time. CONCLUSIONS Unfractionated heparin leads to direct platelet activation and increases platelet aggregation in vitro. Unfractionated heparin causes prolongation of the collagen/adenosine diphosphate closure time in PFA-100 testing, possibly as a result of direct binding to von Willebrand factor in solution and interference with von Willebrand factor-glycoprotein Ib binding.
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Affiliation(s)
- Marlene S Williams
- Department of Medicine, Johns Hopkins Medical Institute, Baltimore, MD, USA
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19
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van Werkum JW, Heestermans AACM, Deneer VHM, Hackeng CM, ten Berg JM. Clopidogrel resistance: fact and fiction. Future Cardiol 2006; 2:215-28. [DOI: 10.2217/14796678.2.2.215] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The antiplatelet agent clopidogrel in combination with aspirin has been shown to reduce thrombotic events in patients with acute coronary syndromes and/or who are undergoing percutaneous coronary intervention. However, a large interindividual response variability to clopidogrel has been described. The reported rates of inadequate clopidogrel response vary considerably depending on the definition and methodologies used to measure the inhibition of platelet function. Recently, several (small) studies have demonstrated the clinical relevance of an inadequate response to clopidogrel. Moreover, several factors have been associated with a high interindividual variability in response to clopidogrel. These are: dosing, impaired intestinal absorption, cytochrome P450 3A4 and 3A5 activity, drug–drug interactions, polymorphisms of the receptors involved in the process of arterial thrombosis and hemostasis, and the method of measurement of platelet function. Future research for the evaluation of clopidogrel resistance should be based on the assessment of selective P2Y12 receptor inhibition (e.g., the vasodilator-stimulated phosphoprotein-assay or the measurement of stabilization of platelet aggregates) with quick and simple tests. Only then can we reveal the true prevalence and impact of clopidogrel resistance.
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Affiliation(s)
- JW van Werkum
- Department of Cardiology, St. Antonius Hospital, Nieuwegein, The Netherlands
| | - AACM Heestermans
- Department of Cardiology, St. Antonius Hospital, Nieuwegein, The Netherlands
| | - VHM Deneer
- Department of Clinical Pharmacy, St. Antonius Hospital, Nieuwegein, The Netherlands
| | - CM Hackeng
- Department of Clinical Pharmacy, St. Antonius Hospital, Nieuwegein, The Netherlands
| | - JM ten Berg
- Department of Cardiology, St. Antonius Hospital, PO Box 2500 3435 CM Nieuwegein, The Netherlands
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20
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Hayward CPM, Harrison P, Cattaneo M, Ortel TL, Rao AK. Platelet function analyzer (PFA)-100 closure time in the evaluation of platelet disorders and platelet function. J Thromb Haemost 2006; 4:312-9. [PMID: 16420557 DOI: 10.1111/j.1538-7836.2006.01771.x] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Closure time (CT), measured by platelet function analyzer (PFA-100) device, is now available to the clinical laboratory as a possible alternative or supplement to the bleeding time test. AIM On behalf of the Platelet Physiology Subcommittee of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis (ISTH-SSC), a working Group was formed to review and make recommendations on the use of the PFA-100 CT in the evaluation of platelet function within the clinical laboratory. METHODS The Medline database was searched to review the published information on the PFA-100 CT in the evaluation of platelet disorders and platelet function. This information, and expert opinion, was used to prepare a report and generate consensus recommendations. RESULTS Although the PFA-100 CT is abnormal in some forms of platelet disorders, the test does not have sufficient sensitivity or specificity to be used as a screening tool for platelet disorders. A role of the PFA-100 CT in therapeutic monitoring of platelet function remains to be established. CONCLUSIONS The PFA-100 closure time should be considered optional in the evaluation of platelet disorders and function, and its use in therapeutic monitoring of platelet function is currently best restricted to research studies and prospective clinical trials.
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Affiliation(s)
- C P M Hayward
- McMaster University and the Hamilton Regional Laboratory Medicine Program, Hamilton, ON, Canada.
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Abstract
UNLABELLED Pregnancy is a hypercoagulable state that increases the risk of thromboembolic events. These risks may be further increased in the presence of an acquired or inherited thrombophilia. Thrombophilias have been associated with both maternal and fetal complications. The use of anticoagulants during pregnancy may reduce the risk of maternal thromboses as well as the risk of adverse pregnancy outcomes. The choice of an anticoagulant requires consideration of maternal risks, potential for teratogenicity, the underlying condition necessitating the treatment, and cost. This review examines the options for anticoagulation, the clinical situations that may warrant such treatment, and factors to be considered at delivery and during the postpartum period. TARGET AUDIENCE Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES After completion of this article, the reader should be able to describe the roles of acquired and inherited thrombophilia in furthering the hypercoagulable state of pregnancy, identify the potential consequences of using anticoagulants during pregnancy, and summarize the treatment options when anticoagulation is required during pregnancy.
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Affiliation(s)
- Andra H James
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Coakley M, Self R, Marchant W, Mackie I, Mallett SV, Mythen M. Use of the platelet function analyser (PFA-100) to quantify the effect of low dose aspirin in patients with ischaemic heart disease. Anaesthesia 2005; 60:1173-8. [PMID: 16288614 DOI: 10.1111/j.1365-2044.2005.04291.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Continuing aspirin up until surgery in cardiac surgical patients may increase peri-operative blood loss. It is possible that there is a subset of patients particularly sensitive to aspirin. The platelet function analyser (PFA-100) can demonstrate the antiplatelet effect of aspirin. This study was designed to assess the effect of daily 75 mg aspirin on platelet function, as measured by the PFA-100, in 92 patients with ischaemic heart disease. Patients were classified into three groups according to their PFA-100 results; aspirin hyper-responders (16%), aspirin normal responders (33%) and aspirin non-responders (51%). The PFA-100 has potential as a screening tool to identify patients who are either hyper-responsive or resistant to aspirin. Pre-operative PFA-100 screening to isolate aspirin hyper-responders could enable the vast majority of patients to continue with aspirin therapy pre-operatively, avoiding the risks of stopping treatment.
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Affiliation(s)
- M Coakley
- Specialist Registrar, Department of Anaesthesia, Royal Free Hospital, Pond Street, Hampstead, London NW3 2QG, UK
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Golański J, Chłopicki S, Golański R, Gresner P, Iwaszkiewicz A, Watala C. Resistance to Aspirin in Patients After Coronary Artery Bypass Grafting Is Transient. Ther Drug Monit 2005; 27:484-90. [PMID: 16044106 DOI: 10.1097/01.ftd.0000158084.84071.41] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The aim of the present study was to assess the responsiveness of blood platelets to aspirin in patients following coronary artery bypass grafting (CABG) surgery. Aspirin was administered following CABG in 24 operated patients (aged 63.2 +/- 6.3 years). Platelet function was monitored on the 10th postoperative day (A) and 1 month after CABG (B) with the use of whole-blood aggregometry (WBEA) and PFA-100 closure time (PFA-100 CTCEPI). Normal platelet response to aspirin was defined by 3 criteria: the complete inhibition of WBEA induced by arachidonic acid (0.5 mmol/L), partial inhibition of collagen (1 microg/mL)-induced aggregation (WBEA < 14 Omega), and prolongation of PFA-100 CTCEPI (>150 seconds) ("good responders"). Depending on whether 0, 1, 2, or 3 of these 3 criteria were fulfilled, patients were classified as "nonresponders," "weak responders," "incomplete responders," or "good responders," respectively. On the 10th postoperative day, there were 3 good responders, 6 incomplete responders, 11 weak responders, and 4 nonresponders among 24 patients. In contrast, 1 month after CABG within the same group of 24 patients there were 18 good responders, 5 incomplete responders, and 1 weak responder. Using a new methodology to assess impaired platelet responsiveness to aspirin ex vivo, we describe here the transient nature of "aspirin resistance" following CABG. These results indicate the necessity for the prolonged monitoring of the antiplatelet effectiveness of aspirin in the postoperative period after CABG.
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Affiliation(s)
- Jacek Golański
- Department of Haemostasis and Haemostatic Disorders, Medical University of Lodz, Lodz, Poland
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24
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Harrison P. The role of PFA-100R testing in the investigation and management of haemostatic defects in children and adults. Br J Haematol 2005; 130:3-10. [PMID: 15982339 DOI: 10.1111/j.1365-2141.2005.05511.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The PFA-100 provides a simple global measure of high shear-dependent platelet function, and as such is not diagnostic or specific to any disorder. Prolonged closure times must be interpreted in conjunction with a full blood count, von Willebrand factor (VWF) screen and other platelet tests. The PFA-100 may also give false negative results with relatively common platelet defects. If clinical suspicion is high, further detailed platelet function testing and VWF screening are required to exclude abnormal platelet function, even if the PFA-100 is normal. In more recent studies the PFA-100 has been used for preoperative identification and management of surgical patients with haemostatic defects and for assessing the clinical effectiveness of platelet transfusion therapy. This review highlights the up to date, evidence-based, advantages and disadvantages of the PFA-100 test in the investigation and management of haemostatic disorders in both children and adults.
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Affiliation(s)
- Paul Harrison
- Oxford Haemophilia Centre and Thrombosis Unit, Churchill Hospital, Headington, Oxford, UK.
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25
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Kerényi A, Soltész P, Veres K, Szegedi G, Muszbek L. Monitoring platelet function by PFA-100 closure time measurements during thrombolytic therapy of patients with myocardial infarction. Thromb Res 2005; 116:139-44. [PMID: 15907529 DOI: 10.1016/j.thromres.2004.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2004] [Revised: 08/22/2004] [Accepted: 10/03/2004] [Indexed: 11/27/2022]
Affiliation(s)
- Adrienne Kerényi
- Department of Clinical Biochemistry and Molecular Pathology, University of Debrecen, Medical and Health Science Center, Debrecen, Hungary
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26
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Reiter R, Jilma-Stohlawetz P, Horvath M, Jilma B. Additive effects between platelet concentrates and desmopressin in antagonizing the platelet glycoprotein IIb/IIIa inhibitor eptifibatide. Transfusion 2005; 45:420-6. [PMID: 15752161 DOI: 10.1111/j.1537-2995.2005.04021.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Platelet (PLT) glycoprotein (GP) IIb/IIIa receptor antagonists have demonstrated efficacy in decreasing ischemic complications of percutaneous coronary intervention and/or unstable angina. In case of bleeding, the drug can be stopped and PLT transfusions can be given. STUDY DESIGN AND METHODS This crossover study tested the additive effects of PLT concentrates (PCs) after desmopressin (DDAVP) infusion in antagonizing the anti-PLT effects of GPIIb/IIIa inhibitors and aspirin. After eptifibatide and aspirin infusion (at standard dosages), 10 healthy volunteers received DDAVP or placebo. Thereafter, increasing amounts of PLTs from fresh single-donor apheresis concentrates were added in vitro to blood samples of all volunteers to increase PLT counts by 30 x 10(9), 60 x 10(9), or 120 x 10(9) per L. RESULTS Adding platelets in vitro further improved PLT function after DDAVP: it shortened collagen-adenosine diphosphate closure times (p < 0.01), to normal ranges as measured by the PLT function analyzer (PFA-100). In contrast, normal PLT function could not be restored even when PLT counts were increased by 50 percent (120 x 10(9)/L) in the placebo group. CONCLUSION Combined use of PLTs from fresh apheresis PC and DDAVP additively enhances recovery of normal PLT function after eptifibatide infusion. Such a strategy may help to avoid excessive transfusion of PC.
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Affiliation(s)
- Rosemarie Reiter
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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27
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Golanski J, Pluta J, Baraniak J, Watala C. Limited usefulness of the PFA-100 for the monitoring of ADP receptor antagonists--in vitro experience. Clin Chem Lab Med 2004; 42:25-9. [PMID: 15061376 DOI: 10.1515/cclm.2004.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have evaluated the usefulness of the PFA-100 system (collagen/ADP and collagen/epinephrine cartridges) to assess the in vitro effects of a few platelet function inhibitors: Aspisol (60 microg/ml), 4-[4-[4-(aminoiminomethyl]-1-piperazinyl]-1-piperidineactetic acid, hydrochloride trihydrate (GR144053F, fibrinogen receptor antagonist, 100 nM), adenosine-3',5'-diphosphate (A3P5P, P2Y1 ADP receptor antagonist, 500 microM) and Bis[(adenosine-5'-O-phosphorodithioyl)methylene]-phosphinic acid (APTMPA, P2Y12 ADP receptor antagonist, 500 microM) on platelet function, as compared with the other commonly used diagnostic technique, a whole blood electrical aggregometry (20 microM ADP or 0.5 mM arachidonic acid). The in vitro studies were carried out on a group of 38 subjects. Whereas all the examined platelet antagonists and inhibitors almost completely blocked the 20 microM ADP- or 0.5 mM arachidonic acid-induced (in the case of acetylsalicylic acid) whole blood aggregation, only two inhibitors (Aspisol and GR144053F) remained effective in a significant prolongation of the PFA-100 occlusion time. Otherwise, using the PFA-100 system we were not able to detect the inhibitory actions of ADP receptor antagonists- P2Y1 and P2Y12. Our findings point to a limited usefulness of the PFA-100 system for the monitoring of the effectiveness of ADP receptor antagonists. The outcomes of this study show that platelet aggregometry in whole blood is characterised by the highest sensitivity in the monitoring of the investigated blood platelet inhibitors.
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Affiliation(s)
- Jacek Golanski
- Department of Haemostasis and Haemostatic Disorders, Medical University of Lodz, Lodz, Poland
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28
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Golański J, Nocuń M, Rózalski M, Drygas W, Watała C. An in vitro model for the detection of reduced platelet sensitivity to acetylsalicylic acid. Blood Coagul Fibrinolysis 2004; 15:187-95. [PMID: 15091007 DOI: 10.1097/00001721-200403000-00011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A discovery of 'aspirin resistance' has prompted the search for fast and reliable methods for the monitoring of antiplatelet efficacy of acetylsalicylic acid (ASA). Our aims were: (1) to evaluate the in vitro model-based method for detecting a reduced platelets' sensitivity to ASA using a point-of-care platelet function analyser PFA-100; and (2) to propose a simple method of data analysis that might be successfully employed to discriminate between 'good' and 'poor' responders to aspirin. Whole blood platelets from healthy volunteers were incubated in vitro with 30 microg/ml ASA (the in vitro method under evaluation) or analysed following a 10-day intake of an average 150 mg ASA (Aspirin Protect) daily (the reference ex vivo method). According to polynomial regression analysis of the bimodally distributed data, the donors with lower ('ASA poor responders') or higher platelet sensitivity to ASA ('ASA good responders') were discriminated at 58.6% of platelet function inhibition. Despite the similar proportions of 'ASA poor responders' (44 versus 41% using the ex vivo and in vitro tests, respectively), 30% of discordant classifications point to a rather unsatisfactory convergence between both methods. Due to a considerable discordance between the in vitro and ex vivo tests of ASA efficacy performed with the use of the PFA-100 system, the former cannot be reliably and interchangeably used for the monitoring of aspirin therapy and the selection of an effective therapeutic ASA dose. A novel approach to data analysis of the distribution of platelet inhibition rates facilitates an evaluation of cut-off points required to discriminate between 'poor responders' and 'good responders' to aspirin.
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Affiliation(s)
- Jacek Golański
- Department of Haemostasis and Haemostatic Disorders and Department of Social and Preventive Medicine, Medical University of Lodz, Lodz, Poland
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Kozłowska-Wojciechowska M, Jastrzebska M, Naruszewicz M, Foltyńska A. Impact of margarine enriched with plant sterols on blood lipids, platelet function, and fibrinogen level in young men. Metabolism 2003; 52:1373-8. [PMID: 14624393 DOI: 10.1016/s0026-0495(03)00286-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The effects of margarines enriched with omega-6 polyunsaturated fatty acids (PUFA), as well as those containing plant sterols or stanols, on reduction of plasma low-density lipoprotein-cholesterol (LDL-C) have been extensively studied. However, their impact on fibrinogen (Fb) concentration and blood platelet function is much less known. Our research involved 42 healthy male students (average age, 23.7 +/- 1.6) who during the research period were subjected to a controlled regime of nutrition and physical activity. After a period of diet stabilization involving 30 g butter daily in 2 servings, the subjects were randomly divided into 2 groups. In the first group, the butter was replaced by the same quantity of PUFA margarine, while the second group received margarine with added plant sterols instead of butter. The subjects consuming margarine with sterols showed a significant (11%) decrease in LDL-C (P<.001). Margarine rich in PUFA caused a 6% reduction in LDL-C (P<.01), with a simultaneous 3% reduction in high-density lipoprotein-cholesterol (HDL-C) (P<.001). Both types of margarine increased the concentration of Fb (P<.001), without exceeding the normal medium value of 2.8 g/L. After the consumption of margarine with sterols, the adhesion and aggregation time of blood platelets was significantly prolonged after collagen-epinephrine activation. Margarine with sterols, through its antiplatelet activity and the significant reduction of LDL-C, can play a vital role in the nonpharmacologic prevention of circulatory diseases.
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Fattorutto M. Measurement of the effect of ticlopidine with the platelet function analyser (PFA-100) during coronary stent implantation. Am Heart J 2003; 146:E8. [PMID: 12947379 DOI: 10.1016/s0002-8703(03)00178-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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31
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Abstract
The roles of platelets in hemostasis and arterial thrombosis involve their adherence to sites of vessel injury or ruptured atherosclerotic plaques, aggregation to form hemostatic plugs or thrombi, and acceleration of the coagulation cascade leading to the formation of thrombin. These roles of platelets are described in this review, hereditary platelet defects and other abnormalities associated with bleeding disorders are listed, and the various aggregating agents are discussed. A number of tests of platelet function are reviewed, including a description of their advantages and disadvantages: bleeding time determination; measurement of platelet aggregation in citrated platelet-rich plasma by recording changes in light transmission; measurement of platelet aggregation in citrated whole blood by impedance aggregometry; measurement of platelet-related hemostasis with the high shear Platelet Function Analyzer (PFA-100) system and the Ultegra Rapid Platelet Function Assay; use of the Cone and Plate(let) Analyzer to measure platelet adherence and aggregation under conditions of high shear; measurement of secretion of granule contents (ATP, 14C-serotonin, platelet factor 4, beta-thromboglobulin) and the formation of thromboxane B(2); and use of flow cytometry to assess the state of platelet activation (including conformational changes in membrane glycoproteins and surface expression of P-selectin and phosphatidylserine) ex vivo and in vitro following addition of agonists, and to measure levels of platelet membrane glycoproteins in the detection of inherited deficiencies.
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Affiliation(s)
- Margaret L Rand
- Division of Haematology/Oncology, The Hospital for Sick Children, 555 University Ave., Toronto, Ont., Canada M5G 1X8.
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32
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Affiliation(s)
- George Mychaskiw
- Department of Anesthesiology University of Mississippi School of Medicine Jackson, Mississippi
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Grau AJ, Reiners S, Lichy C, Buggle F, Ruf A. Platelet function under aspirin, clopidogrel, and both after ischemic stroke: a case-crossover study. Stroke 2003; 34:849-54. [PMID: 12637702 DOI: 10.1161/01.str.0000064326.65899.ac] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Combined antiplatelet agents may offer additive protection over single drugs after stroke. We investigated whether platelet activation is reduced under combined aspirin and clopidogrel compared with each drug alone. METHODS In a case-crossover study, 31 patients with previous atherothrombotic or lacunar stroke who were treated with aspirin (100 to 300 mg/d) received clopidogrel (75 mg/d) and both aspirin and clopidogrel for 4 weeks. Platelet function in whole blood was studied after each treatment period and in healthy control subjects to assess activation-dependent antigens CD62p and CD63 by flow cytometry and collagen/epinephrine (CEPI-CT) and collagen/ADP (CADP-CT) closure times with the platelet function analyzer PFA-100, which investigates platelet-related function under shear stress. RESULTS CD62p expression and CD63 expression were not different under the 3 treatment regimens. CD63 but not CD62p expression was lower in control subjects than in stroke patients regardless of the antiplatelet treatment (P<0.05). CEPI-CT was prolonged under aspirin and aspirin plus clopidogrel compared with clopidogrel monotherapy (P<0.0001). CADP-CT was longer under combination therapy than under aspirin (P=0.0009) or clopidogrel (P=0.0074) or in control subjects (P=0.0010), mainly because of strong prolongation in a patient subgroup (28%). CONCLUSIONS CD63 expression reflecting the release of platelet lysosomes is consistently increased after stroke and incompletely suppressed by treatment with aspirin, clopidogrel, or both. The strong prolongation of CADP-CT under combined aspirin and clopidogrel in a patient subgroup may indicate a lower risk of thrombosis but also a higher risk of hemorrhage. The predictive value of platelet activation parameters requires investigation in prospective studies.
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Affiliation(s)
- Armin J Grau
- Neurology Department, University of Heidelberg, Germany.
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Mueller T, Haltmayer M, Poelz W, Haidinger D. Monitoring aspirin 100 mg and clopidogrel 75 mg therapy with the PFA-100 device in patients with peripheral arterial disease. Vasc Endovascular Surg 2003; 37:117-23. [PMID: 12669143 DOI: 10.1177/153857440303700206] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A tool to identify vascular patients who receive antiplatelet therapy nd to distinguish between responders and non-responders to antiplatelet therapy could be of clinical importance. The present observational study was designed to investigate whether the PFA-100 device (Dade Behring) is suitable to detect long-term therapy of aspirin (100 mg/d) and/or clopidogrel (75 mg/d) in a cohort of patients with peripheral arterial disease (PAD). A total of 150 consecutive patients with PAD were studied; 34 patients were excluded from the study due to irregular intake of antiplatelet therapy or due to method limitations. Of the remaining 116 patients, 42 had no antiplatelet therapy, 47 had daily aspirin (100 mg) intake, 19 were administered clopidogrel 75 mg daily, and 10 received a medication with 100 mg aspirin plus clopidogrel 75 mg daily, all for at least 10 days. Nonparametric Kruskal-Wallis test with post hoc comparisons showed that collagen plus epinephrine (CEPI) closure times of the patient group receiving aspirin and the group receiving aspirin plus clopidogrel were similar (p>0.05). In contrast, both patient groups exhibited prolonged CEPI values compared to patients without antiplatelet therapy and patients taking clopidogrel (p<0.001). Finally, both patients without antiplatelet therapy and patients with clopidogrel did not show marked differences with respect to their CEPI values (p>0.05). However, Kruskal-Wallis test results revealed that collagen plus adenosine-5'-diphosphate closure times were not significantly different in all four patient groups (p=0.257). In conclusion, the PFA-100 device may be a suitable tool for monitoring aspirin 100 mg therapy, but it is not appropriate for the detection of clopidogrel administration in its current setup. Although it appears plausible that patients with PAD could benefit from monitoring platelet inhibition, clear evidence for this concept is still lacking.
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Affiliation(s)
- Thomas Mueller
- Department of Laboratory Medicine, Konventhospital Barmherzige Brueder Linz, Austria
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Andersen K, Hurlen M, Arnesen H, Seljeflot I. Aspirin non-responsiveness as measured by PFA-100 in patients with coronary artery disease. Thromb Res 2002; 108:37-42. [PMID: 12586130 DOI: 10.1016/s0049-3848(02)00405-x] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION The purpose of the present study was to study the concept of aspirin resistance or non-responsiveness by investigating the response to long-term aspirin therapy in patients with a former acute myocardial infarction (AMI). MATERIALS AND METHODS Patients with an AMI (n=202) randomly assigned to aspirin 160 mg/day (n=71), aspirin 75 mg/day and warfarin (INR 2.0-2.5) (n=58) or warfarin (INR 2.8-4.2) (n=73) were evaluated by the PFA-100(R), biochemical variables and clinical events after a mean treatment period of 4 years. RESULTS The limit for being an aspirin non-responder was defined as the 95th percentile value in the warfarin alone group (196 s) with the epinephrine cartridge. In patients on aspirin alone 25/71 (35%) were non-responders and on the combination 23/58 (40%). With the adenosine diphosphate (ADP) cartridge only minor differences were found. The levels of thromboxane B(2) in both aspirin groups, in responders as well as in non-responders, were extremely low compared to the warfarin alone group. Evaluating both aspirin groups together (n=129), the levels of soluble P-selectin were significantly higher in non-responders as compared to responders (p=0.012). During the observation period of 4 years with limited number of events, there was a tendency for higher event rates in non-responders as compared to responders (36% vs. 24%, p=0.28). CONCLUSIONS In our evaluation of the PFA-100(R) a considerable number of post-AMI patients seemed to be non-responders to long-term aspirin therapy in doses of 75 and 160 mg/day. Circulating levels of P-selectin were higher in the non-responders. A tendency to higher incidence of clinical events among non-responders was observed.
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Affiliation(s)
- Kjell Andersen
- Medical Department, Central Hospital of Hedmark, Hamar N-2315, Norway.
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Hézard N, Metz D, Nazeyrollas P, Droullé C, Potron G, Nguyen P. PFA-100 and flow cytometry: can they challenge aggregometry to assess antiplatelet agents, other than GPIIbIIIa blockers, in coronary angioplasty? Thromb Res 2002; 108:43-7. [PMID: 12586131 DOI: 10.1016/s0049-3848(02)00391-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Platelet response to inhibitors varies widely, leading to a higher risk of abrupt closure events in insufficiently treated-coronary heart disease patients. The aim of this study was to compare, in patients under various antiplatelet regimens, three platelet function assays: aggregometry, PFA-100 and flow cytometry. These assays stand for available tests, as "ready-to-use" device (PFA-100) and sophisticated assay (cytometry). We chose the setting of percutaneous coronary intervention as a standardized procedure to determine which test was appropriate to detect the effect of (1) an aspirin bolus in patients under long-term aspirin treatment, and (2) ticlopidin in case of stent implantation. METHODS Fifty patients under oral aspirin treatment were randomized to receive a bolus of 500 mg aspirin before angioplasty (n=25). Ticlopidin was given at a 500 mg loading dose in the case of stent implantation (n=38). Platelet function was assessed before, at 2 and 24 h after angioplasty. RESULTS Considering aspirin antiplatelet effect, the following was observed: (1) a lack of further inhibition after the bolus whatever assay was used and (2) a disagreement between aggregometry and PFA-100 to classify patients as being poor or good aspirin responders (kappa were 0.11 and 0.28 between ADP 4 or 6 microM aggregation, respectively, and PFA-100). Another finding was the good performance of flow cytometry, which evaluated GPIIbIIIa activation, and aggregometry, to detect ticlopidin the day after the loading dose. In contrast, PFA-100 was insensitive to ticlopidin. CONCLUSION Current assays are not interchangeable to monitor antiplatelet treatment in daily practice.
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Affiliation(s)
- Nathalie Hézard
- Laboratoire Central d'Hématologie, CHU Robert Debré, 51092 Reims Cédex, France
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Abstract
The PFA-100 (platelet function analyzer) is a relatively new tool for the investigation of primary hemostasis. Recent studies have shown its utility as a screening tool for investigating possible von Willebrand disorder (VWD) and various platelet disorders. More recently, the PFA-100 has been shown to be valuable in monitoring desmopressin acetate (DDAVP) therapy in both VWD and platelet disorders. The PFA-100 has also been evaluated in many other studies for its utility in assessing drug effects, for potential monitoring of antiplatelet medication (including aspirin), or for evaluation of overall primary hemostasis in various clinical disorders or during surgical procedures. This article reviews current findings and highlights the benefits and limitations of the clinical utility of the PFA-100. Ultimately, the greatest strengths of the PFA-100 are its simplicity of use and excellent sensitivity to particular hemostatic disturbances such as VWD, platelet disorders, and platelet-affecting medication. However, because it is thus a global test system, this also creates a significant limitation because the PFA-100 is not specific for, nor predictive of, any particular disorder. However, used appropriately, the PFA-100 can be considered a worthwhile addition to any hemostasis laboratory involved in the diagnosis or therapeutic monitoring of bleeding disorders and potentially of antiplatelet medication. This review should be valuable to both hemostasis scientists and clinical specialists.
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Affiliation(s)
- Emmanuel J Favaloro
- Diagnostic Haemostasis Laboratory, Department of Hematology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Western Sydney Area Health Service, Westmead, NSW, 2145, Australia.
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Madan M, Berkowitz SD, Christie DJ, Smit AC, Sigmon KN, Tcheng JE. Determination of platelet aggregation inhibition during percutaneous coronary intervention with the platelet function analyzer PFA-100. Am Heart J 2002; 144:151-8. [PMID: 12094202 DOI: 10.1067/mhj.2002.123581] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND A simple device to rapidly evaluate platelet function may aid in optimizing glycoprotein IIb/IIIa inhibition during percutaneous coronary intervention (PCI). We prospectively studied platelet function in 250 patients receiving abciximab or eptifibatide during PCI. METHODS AND RESULTS The platelet function analyzer PFA-100 (Dade-Behring, Deerfield, Ill) measures platelet function by determining the time to occlusion of an aperture in a biochemically active membrane as whole blood flows under high shear conditions. Platelet aggregation causes aperture occlusion, and results are reported as a closure time (CT). All patients received either abciximab or eptifibatide, along with aspirin and heparin; patients undergoing stent implantation received aspirin and a thienopyridine postprocedure. The CT was measured at baseline and 10 minutes, 4 hours, 12 hours (abciximab-only), and 24 hours after the bolus. Profound inhibition was exhibited in most patients shortly after the platelet inhibitor bolus and during the course of therapy. We observed recovery of platelet function 12 hours after discontinuation of abciximab, with a high degree of interpatient variability, and ongoing profound platelet inhibition 4 to 6 hours after the discontinuation of eptifibatide. Among patients treated with abciximab, patients who were obese recovered from platelet inhibition sooner than patients who were not obese, whereas patients who were elderly had delayed recovery compared with patients who were not elderly. Failure to achieve maximal platelet inhibition (nonclosure) at 10 minutes indicated a possible association with adverse clinical events at the 6-month follow-up examination (60% vs 20%). CONCLUSIONS PFA-100 is a rapid simple assay used as a means of assessing inhibition of platelet aggregation during PCI performed with glycoprotein IIb/IIIa inhibition. Failure to achieve nonclosure early after the initiation of abciximab therapy warrants further investigation because there may be an association with adverse cardiac events at 6-month follow-up.
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Affiliation(s)
- Mina Madan
- Duke Clinical Research Institute, Durham, NC, USA.
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Zeerleder S, Mauron T, Lämmle B, Wuillemin WA. Effect of low-molecular weight dextran sulfate on coagulation and platelet function tests. Thromb Res 2002; 105:441-6. [PMID: 12062546 DOI: 10.1016/s0049-3848(02)00041-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Low-molecular weight dextran sulfate (DXS 5000, M(r) 5 kDa) was found to control selectively complement activation without affecting contact activation. However, DXS 5000 being a glycosaminoglycan (GAG) may inhibit coagulation, which might bear the risk of bleeding complications and limit its clinical use. We investigated the influence of DXS 5000 on the prothrombin time (PT), the activated partial thromboplastin time (aPTT), the thrombin time (TT), the inhibitory capacity of human plasma against activated factor X (FXa), and on platelet function as assessed by the platelet function analyzer (PFA-100) and by platelet aggregation studies. The PT steadily increased with increasing DXS 5000 concentration, whereas the aPTT was already prolonged (>300 s) at low DXS 5000 concentrations (100 microg/ml). The TT was >120 s at DXS 5000 concentrations of 1000 microg/ml. The inhibitory capacity of human plasma against FXa was dose-dependently increased by DXS 5000. With increasing DXS 5000 concentrations, a prolonged PFA-100 closure time (CT) was observed. Detailed aggregation studies revealed a dose-dependent inhibition of platelet aggregation with ristocetin by DXS 5000, whereas aggregation with ADP, collagen, and arachidonate was unaffected. DXS 5000 induces a disturbance of primary and secondary hemostasis.
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Affiliation(s)
- Sacha Zeerleder
- Central Hematology Laboratory, University of Bern, Inselspital, CH-3010, Bern, Switzerland
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Abstract
OBJECTIVE To provide both a detailed description of the laboratory tests available in the diagnosis of platelet disorders and a testing algorithm, based on platelet count, that can be used to direct the evaluation of platelet disorders. DATA SOURCES A literature search was conducted using the National Library of Medicine database. STUDY SELECTION The literature on laboratory testing of platelet function was reviewed. DATA EXTRACTION AND DATA SYNTHESIS Based on the literature review, an algorithm for platelet testing was developed. CONCLUSIONS A history of mucocutaneous bleeding often indicates abnormal platelet function that can be associated with a normal, increased, or decreased platelet count. Multiple laboratory procedures can now be used to determine the underlying pathologic condition of platelet dysfunction when other deficiencies or defects of the coagulation cascade or fibrinolysis are ruled out. Simple procedures, such as platelet count, peripheral blood smear, and a platelet function screening test, will often lead the investigator to more specific analyses. Although platelet function testing is often limited to larger medical centers with highly trained technologists, newer technologies are being developed to simplify current procedures and make platelet function testing more accessible. This review provides an algorithm for platelet testing that may be of benefit to pathologists and physicians who deal with hemostatic disorders.
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Affiliation(s)
- Kandice Kottke-Marchant
- Department of Clinical Pathology, The Cleveland Clinic Foundation, L30, 9500 Euclid Ave, Cleveland, OH 44195, USA.
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Jilma B. Platelet function analyzer (PFA-100): a tool to quantify congenital or acquired platelet dysfunction. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 2001; 138:152-63. [PMID: 11528368 DOI: 10.1067/mlc.2001.117406] [Citation(s) in RCA: 222] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- B Jilma
- Department of Clinical Pharmacology-TARGET, University of Vienna, Austria
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Tate J, Olencki T, Finke J, Kottke-Marchant K, Rybicki LA, Bukowski RM. Phase I trial of simultaneously administered GM-CSF and IL-6 in patients with renal-cell carcinoma: clinical and laboratory effects. Ann Oncol 2001; 12:655-9. [PMID: 11432624 DOI: 10.1023/a:1011123432765] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Metastatic renal-cell carcinoma is a neoplasm that is minimally responsive to cytotoxic chemotherapy. Tumor regression following therapy with cytokines such as interferon alpha and or interleukin-2 is seen in selected subsets of patients. Investigations with other immunomodulatory cytokines, such as GM-CSF and IL-6 are therefore of interest. PATIENTS AND METHODS A phase I trial of concomitantly administered granulocyte macrophage-colony stimulating factor (3.0 mcg/kg/day s.c. d1-14) and escalating doses of interleukin-6 (1.0, 5.0 or 10.0 microg/kg/day d1-14) was conducted in patients with metastatic renal-cell carcinoma to explore the toxicity of the combination and its hematologic effects. RESULTS The most common side effects seen were fever, fatigue and arthralgias. Dose limiting toxicity included thrombocytosis and hyperbilirubinemia in patients receiving 10 microg/kg/day of IL-6. The hematologic effects of IL-6 and GM-CSF included leukocytoses and thrombocytosis, with increases in peripheral blood progenitors (BFU-E, CFU-GM, and CFU-GEMM). Evidence of platelet activation demonstrated by increased platelet expression of CD62 was found. No clinical responses were observed. CONCLUSIONS The combination of IL-6 and GM-CSF has pleotropic hematologic effects. Further studies with this combination for the treatment of renal-cell carcinoma are not recommended.
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Affiliation(s)
- J Tate
- Department of Hematology and Medical Oncology, The Cleveland Clinic Foundation, Ohio, USA
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Favaloro EJ. Utility of the PFA-100 for assessing bleeding disorders and monitoring therapy: a review of analytical variables, benefits and limitations. Haemophilia 2001; 7:170-9. [PMID: 11260277 DOI: 10.1046/j.1365-2516.2001.00486.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The PFA-100 (platelet function analyser) is a relatively new tool for the investigation of primary haemostasis. Recent studies have shown its utility in monitoring antiplatelet therapy (including aspirin) and as a screening tool for investigating possible von Willebrand disease (vWD) and various platelet disorders. More recently, the PFA-100 has been shown to be of value in monitoring DDAVP therapy in both vWD and platelet disorders. This paper reviews current findings, details the utility of the PFA-100 for some of these purposes, as well as reviewing analytical variables that may complicate the interpretation of results. The author highlights the benefits, as well as noting the limitations, of its use. Ultimately, the greatest strengths of the PFA-100 are its simplicity in use and excellent sensitivity to particular haemostatic disturbances such as vWD, platelet disorders and platelet-affecting medication. However, because it is thus a 'global' test system, this also creates a significant limitation, as the PFA-100 is not specific for, nor predictive of, any particular disorder. However, utilized appropriately, the PFA-100 can be considered a worthwhile addition to any haemostasis laboratory involved in the diagnosis or therapeutic-monitoring of bleeding disorders including vWD and platelet-dysfunctions. This review should be of value to both haemostasis scientists and clinical specialists.
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Affiliation(s)
- E J Favaloro
- Diagnostic Haemostasis Laboratory, Department of Haematology, ICPMR, Westmead Hospital, NSW, Australia.
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Madan M, Berkowitz SD, Christie DJ, Jennings LK, Smit AC, Sigmon KN, Glazer S, Tcheng JE. Rapid assessment of glycoprotein IIb/IIIa blockade with the platelet function analyzer (PFA-100) during percutaneous coronary intervention. Am Heart J 2001; 141:226-33. [PMID: 11174336 DOI: 10.1067/mhj.2001.112489] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND The platelet function analyzer PFA-100 (Dade Behring, Miami, Fla) evaluates platelet function by determining the time to occlusion of an aperture in a membrane coated with collagen and adenosine diphosphate or epinephrine as whole blood flows under shear stress conditions. Platelet aggregation causes aperture occlusion, and results are reported as closure time (CT). Interindividual variability is observed in the level of platelet inhibition achieved with use of the current abciximab dosing regimen (0.25-mg/kg bolus + 10-microg/min infusion for 12 hours). The relationships between specific levels of platelet inhibition and clinical efficacy and safety have not been fully established. METHODS AND RESULTS We prospectively studied platelet function in 27 patients receiving abciximab during percutaneous coronary intervention. This evaluation included determinations of platelet-rich plasma aggregometry, receptor occupancy studies (D3 assay), and CT measurements at baseline and 10 minutes, 4 hours, 12 hours, and 24 hours after the bolus. All patients received abciximab, aspirin, and heparin; patients undergoing coronary stent implantation received aspirin and ticlopidine after the procedure. CT results were reported within 10 minutes after initiation of testing. For 96% of patients, CT was 300 seconds (maximum CT) immediately after abciximab bolus and remained so throughout the infusion. At 24 hours we observed variable recovery from platelet inhibition and in 72% of patients CT returned to normal (< or =130 seconds). CONCLUSIONS Findings with the PFA-100 were similar to results observed with platelet aggregometry and receptor occupancy measurements. Most patients treated with abciximab exhibit normalized platelet function at 24 hours despite moderate levels of receptor occupancy, suggesting dissociation between occupancy and function.
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Affiliation(s)
- M Madan
- Duke Clinical Research Institute, Durham, NC 27710, USA
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Abstract
AbstractThis article focuses on the recent dramatic advances in the applications of monoclonal antibody therapy to hematopoietic and neoplastic disease. The increase in the understanding of the role of growth factors and their receptors in the pathogenesis of malignancy and other undesirable hematological events taken in conjunction with the ability to produce humanized chimeric monoclonal antibodies to these targets is providing a new perspective for the treatment of leukemia, lymphoma and breast cancer, autoimmune disease and for prevention of ischemic complications. Dr. Waldmann describes approaches targeting the Her2/neu and the II-2/IL-15 receptor systems. The Her2/neu receptor is overexpressed in select breast, ovarian, gastric and pancreatic neoplasms. The use of trastuzumab (Herceptin) in the treatment of patients with breast cancer whose tumors overexpress this receptor are reviewed. The IL-2 receptor (Tac) is expressed on select malignant cells (adult T cell leukemia, hairy cell leukemia) and activated T cells involved in autoimmune disease and organ rejection. Humanized anti-Tac alone (daclizumab, Zenapax) or armed with toxins or radionuclides have been used successfully in the treatment of leukemia. Dr. Levy updates the experience with rituximab targeting CD20 on B cell lymphomas and reviews the antibodies to CD3, CD22, CD33, CD52, HLA-DR β chain and HLA-D currently in or proposed for clinical trials, including radiolabelled antibodies. In the last section, Dr. Coller reviews the therapeutic results achieved with abciximab (ReoPro), an antagonist of platelet receptor GPIIbIIIa for the prevention of restenosis in percutaneous coronary interventions and the treatment of unstable angina. The mechanism of action, pharmacology and safety and efficacy of abciximab are reviewed.
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Abstract
This article focuses on the recent dramatic advances in the applications of monoclonal antibody therapy to hematopoietic and neoplastic disease. The increase in the understanding of the role of growth factors and their receptors in the pathogenesis of malignancy and other undesirable hematological events taken in conjunction with the ability to produce humanized chimeric monoclonal antibodies to these targets is providing a new perspective for the treatment of leukemia, lymphoma and breast cancer, autoimmune disease and for prevention of ischemic complications. Dr. Waldmann describes approaches targeting the Her2/neu and the II-2/IL-15 receptor systems. The Her2/neu receptor is overexpressed in select breast, ovarian, gastric and pancreatic neoplasms. The use of trastuzumab (Herceptin) in the treatment of patients with breast cancer whose tumors overexpress this receptor are reviewed. The IL-2 receptor (Tac) is expressed on select malignant cells (adult T cell leukemia, hairy cell leukemia) and activated T cells involved in autoimmune disease and organ rejection. Humanized anti-Tac alone (daclizumab, Zenapax) or armed with toxins or radionuclides have been used successfully in the treatment of leukemia. Dr. Levy updates the experience with rituximab targeting CD20 on B cell lymphomas and reviews the antibodies to CD3, CD22, CD33, CD52, HLA-DR β chain and HLA-D currently in or proposed for clinical trials, including radiolabelled antibodies. In the last section, Dr. Coller reviews the therapeutic results achieved with abciximab (ReoPro), an antagonist of platelet receptor GPIIbIIIa for the prevention of restenosis in percutaneous coronary interventions and the treatment of unstable angina. The mechanism of action, pharmacology and safety and efficacy of abciximab are reviewed.
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