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Collinson RJ, Wilson L, Boey D, Ng ZY, Mirzai B, Chuah HS, Howman R, Grove CS, Malherbe JAJ, Leahy MF, Linden MD, Fuller KA, Erber WN, Guo BB. Transcription factor 3 is dysregulated in megakaryocytes in myelofibrosis. Platelets 2024; 35:2304173. [PMID: 38303515 DOI: 10.1080/09537104.2024.2304173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/02/2024] [Indexed: 02/03/2024]
Abstract
Transcription factor 3 (TCF3) is a DNA transcription factor that modulates megakaryocyte development. Although abnormal TCF3 expression has been identified in a range of hematological malignancies, to date, it has not been investigated in myelofibrosis (MF). MF is a Philadelphia-negative myeloproliferative neoplasm (MPN) that can arise de novo or progress from essential thrombocythemia [ET] and polycythemia vera [PV] and where dysfunctional megakaryocytes have a role in driving the fibrotic progression. We aimed to examine whether TCF3 is dysregulated in megakaryocytes in MPN, and specifically in MF. We first assessed TCF3 protein expression in megakaryocytes using an immunohistochemical approach analyses and showed that TCF3 was reduced in MF compared with ET and PV. Further, the TCF3-negative megakaryocytes were primarily located near trabecular bone and had the typical "MF-like" morphology as described by the WHO. Genomic analysis of isolated megakaryocytes showed three mutations, all predicted to result in a loss of function, in patients with MF; none were seen in megakaryocytes isolated from ET or PV marrow samples. We then progressed to transcriptomic sequencing of platelets which showed loss of TCF3 in MF. These proteomic, genomic and transcriptomic analyses appear to indicate that TCF3 is downregulated in megakaryocytes in MF. This infers aberrations in megakaryopoiesis occur in this progressive phase of MPN. Further exploration of this pathway could provide insights into TCF3 and the evolution of fibrosis and potentially lead to new preventative therapeutic targets.
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Affiliation(s)
- Ryan J Collinson
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Lynne Wilson
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Darren Boey
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Zi Yun Ng
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
- Department of Haematology, Royal Perth Hospital, Perth, WA, Australia
| | - Bob Mirzai
- PathWest Laboratory Medicine, Nedlands, WA, Australia
| | - Hun S Chuah
- Department of Haematology, Royal Perth Hospital, Perth, WA, Australia
- PathWest Laboratory Medicine, Nedlands, WA, Australia
- Department of Haematology, Rockingham General Hospital, Rockingham, WA, Australia
| | - Rebecca Howman
- Department of Haematology, Sir Charles Gairdner Hospital Nedlands Australia
| | - Carolyn S Grove
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
- Department of Haematology, Royal Perth Hospital, Perth, WA, Australia
- Department of Haematology, Sir Charles Gairdner Hospital Nedlands Australia
| | | | - Michael F Leahy
- Department of Haematology, Royal Perth Hospital, Perth, WA, Australia
- PathWest Laboratory Medicine, Nedlands, WA, Australia
| | - Matthew D Linden
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Kathryn A Fuller
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Wendy N Erber
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
- PathWest Laboratory Medicine, Nedlands, WA, Australia
| | - Belinda B Guo
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
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Johnson BZ, O'Halloran E, Stevenson AW, Wood FM, Fear MW, Linden MD. Non-severe burn injury causes sustained platelet hyperreactivity. Burns 2024; 50:585-596. [PMID: 37945506 DOI: 10.1016/j.burns.2023.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/21/2023] [Accepted: 10/06/2023] [Indexed: 11/12/2023]
Abstract
Individuals who present to a hospital for treatment of a burn of any magnitude are more frequently hospitalised for ischemic heart disease, even decades after injury. Blood platelets are key mediators of cardiovascular disease. To investigate platelet involvement in post-burn cardiovascular risk, platelet reactivity was assessed in patients at 2- and 6-weeks after non-severe (TBSA < 20%) burn injury, and in a murine model 30 days after 8% TBSA full-thickness burn injury. Platelets were stimulated with canonical agonists and function reported by GPIIb/IIIa PAC1-binding site, CD62P expression, and formation of monocyte-platelet aggregates. In vivo thrombosis in a modified Folts model of vascular injury was assessed. Burn survivors had elevated frequencies of circulating monocyte-platelet aggregates, and platelets were hyperreactive, primarily to collagen stimulation. Burn plasma did not cause hyper-reactivity when incubated with control platelets. Platelets from burn injured mice also demonstrated increased response to collagen peptides but did not show any change in thrombosis following vascular injury. This study demonstrates the persistence of a small but significant platelet hyperreactivity following burn injury. Although our data does not suggest this heightened platelet sensitivity modulates thrombosis following vascular injury, the contribution of sub-clinical platelet hyperreactivity to accelerating atherogenesis merits further investigation.
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Affiliation(s)
- Blair Z Johnson
- Burn Injury Research Unit, University of Western Australia, Perth, Australia; School of Biomedical Science, University of Western Australia, Perth, Australia
| | - Emily O'Halloran
- Burn Injury Research Unit, University of Western Australia, Perth, Australia
| | - Andrew W Stevenson
- Burn Injury Research Unit, University of Western Australia, Perth, Australia; School of Biomedical Science, University of Western Australia, Perth, Australia
| | - Fiona M Wood
- Burn Injury Research Unit, University of Western Australia, Perth, Australia; Burns Service of Western Australia, WA Department of Health, Nedlands, Australia
| | - Mark W Fear
- Burn Injury Research Unit, University of Western Australia, Perth, Australia; School of Biomedical Science, University of Western Australia, Perth, Australia
| | - Matthew D Linden
- School of Biomedical Science, University of Western Australia, Perth, Australia.
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3
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Richman TR, Ermer JA, Baker J, Siira SJ, Kile BT, Linden MD, Rackham O, Filipovska A. Mitochondrial gene expression is required for platelet function and blood clotting. Cell Rep 2023; 42:113312. [PMID: 37889747 DOI: 10.1016/j.celrep.2023.113312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/20/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
Platelets are anucleate blood cells that contain mitochondria and regulate blood clotting in response to injury. Mitochondria contain their own gene expression machinery that relies on nuclear-encoded factors for the biogenesis of the oxidative phosphorylation system to produce energy required for thrombosis. The autonomy of the mitochondrial gene expression machinery from the nucleus is unclear, and platelets provide a valuable model to understand its importance in anucleate cells. Here, we conditionally delete Elac2, Ptcd1, or Mtif3 in platelets, which are essential for mitochondrial gene expression at the level of RNA processing, stability, or translation, respectively. Loss of ELAC2, PTCD1, or MTIF3 leads to increased megakaryocyte ploidy, elevated circulating levels of reticulated platelets, thrombocytopenia, and consequent extended bleeding time. Impaired mitochondrial gene expression reduces agonist-induced platelet activation. Transcriptomic and proteomic analyses show that mitochondrial gene expression is required for fibrinolysis, hemostasis, and blood coagulation in response to injury.
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Affiliation(s)
- Tara R Richman
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA 6009, Australia; ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA 6009, Australia; Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA 6009, Australia; Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia
| | - Judith A Ermer
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA 6009, Australia; ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA 6009, Australia; Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Jessica Baker
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA 6009, Australia; ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA 6009, Australia; Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA 6009, Australia; Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia
| | - Stefan J Siira
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA 6009, Australia; ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA 6009, Australia; Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, WA 6009, Australia; Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia
| | - Benjamin T Kile
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Matthew D Linden
- Pathology and Laboratory Science, The University of Western Australia, Perth, WA, Australia
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, WA 6009, Australia; ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA 6009, Australia; Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia; Curtin Medical School, Curtin University, Bentley, WA 6102, Australia; Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6102, Australia
| | - Aleksandra Filipovska
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, WA 6009, Australia; Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia.
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4
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Drop J, Letunica N, Van Den Helm S, Heleen van Ommen C, Wildschut E, de Hoog M, van Rosmalen J, Barton R, Yaw HP, Newall F, Horton SB, Chiletti R, Johansen A, Best D, McKittrick J, Butt W, d’Udekem Y, MacLaren G, Linden MD, Ignjatovic V, Attard C, Monagle P. Factors XI and XII in extracorporeal membrane oxygenation: longitudinal profile in children. Res Pract Thromb Haemost 2023; 7:102252. [PMID: 38193071 PMCID: PMC10772870 DOI: 10.1016/j.rpth.2023.102252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/30/2023] [Accepted: 09/21/2023] [Indexed: 01/10/2024] Open
Abstract
Background Extracorporeal membrane oxygenation (ECMO) is used in children with cardiopulmonary failure. While the majority of ECMO centers use unfractionated heparin, other anticoagulants, including factor XI and factor XII inhibitors are emerging, which may prove suitable for ECMO patients. However, before these anticoagulants can be applied in these patients, baseline data of FXI and FXII changes need to be acquired. Objectives This study aimed to describe the longitudinal profile of FXI and FXII antigenic levels and function before, during, and after ECMO in children. Methods This is a prospective observational study in neonatal and pediatric patients with ECMO (<18 years). All patients with venoarterial ECMO and with sufficient plasma volume collected before ECMO, on day 1 and day 3, and 24 hours postdecannulation were included. Antigenic levels and functional activity of FXI and FXII were determined in these samples. Longitudinal profiles of these values were created using a linear mixed model. Results Sixteen patients were included in this study. Mean FXI and FXII antigenic levels (U/mL) changed from 7.9 and 53.2 before ECMO to 6.0 and 34.5 on day 3 and they recovered to 8.8 and 39.4, respectively, after stopping ECMO. Function (%) of FXI and FXII decreased from 59.1 and 59.0 to 49.0 and 50.7 on day 3 and recovered to 66.0 and 54.4, respectively. Conclusion This study provides the first insights into changes of the contact pathway in children undergoing ECMO. FXI and FXII antigen and function change during ECMO. Results from this study can be used as starting point for future contact pathway anticoagulant studies in pediatric patients with ECMO.
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Affiliation(s)
- Joppe Drop
- Department of Paediatrics, Division of Paediatric Hematology, Erasmus Medical Centre—Sophia Children’s Hospital, Rotterdam, South Holland, The Netherlands
- Department of Paediatrics, Division of Paediatric Intensive Care and Paediatric Surgery, Erasmus Medical Centre – Sophia Children’s Hospital, Rotterdam, South Holland, The Netherlands
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
| | - Natasha Letunica
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
| | - Suelyn Van Den Helm
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
| | - C. Heleen van Ommen
- Department of Paediatrics, Division of Paediatric Hematology, Erasmus Medical Centre—Sophia Children’s Hospital, Rotterdam, South Holland, The Netherlands
| | - Enno Wildschut
- Department of Paediatrics, Division of Paediatric Intensive Care and Paediatric Surgery, Erasmus Medical Centre – Sophia Children’s Hospital, Rotterdam, South Holland, The Netherlands
| | - Matthijs de Hoog
- Department of Paediatrics, Division of Paediatric Intensive Care and Paediatric Surgery, Erasmus Medical Centre – Sophia Children’s Hospital, Rotterdam, South Holland, The Netherlands
| | - Joost van Rosmalen
- Department of Biostatistics, Erasmus University Medical Center, Rotterdam, South Holland, The Netherlands
- Department of Epidemiology, Erasmus University Medical Center, University Medical Center Rotterdam, Rotterdam, South Holland, The Netherlands
| | - Rebecca Barton
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Clinical Haematology, The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Hui Ping Yaw
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
| | - Fiona Newall
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Clinical Haematology, The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Stephen B. Horton
- Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Cardiac Surgery, The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Roberto Chiletti
- Department of Intensive Care, The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Paediatric Intensive Care Research Group, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Critical Care, The University of Melbourne, Melbourne, Victoria, Australia
| | - Amy Johansen
- Department of Intensive Care, The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Paediatric Intensive Care Research Group, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
| | - Derek Best
- Department of Intensive Care, The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Paediatric Intensive Care Research Group, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
| | - Joanne McKittrick
- Department of Intensive Care, The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Warwick Butt
- Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Intensive Care, The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Paediatric Intensive Care Research Group, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Critical Care, The University of Melbourne, Melbourne, Victoria, Australia
| | - Yves d’Udekem
- Department of Cardiac Surgery, Children’s National Heart Institute, Washington DC, USA
| | - Graeme MacLaren
- Cardiothoracic Intensive Care Unit, National University Health System, Singapore
| | - Matthew D. Linden
- School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Vera Ignjatovic
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
- Johns Hopkins All Children’s Institute for Clinical and Translational Research, St Petersburg, Florida, USA
- Department of Paediatrics, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Chantal Attard
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Paul Monagle
- Haematology Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Clinical Haematology, The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Kids Cancer Centre, Sydney Children’s Hospital, Randwick, New South Wales, Australia
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5
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Van Den Helm S, Letunica N, Barton R, Weaver A, Yaw HP, Karlaftis V, McCafferty C, Cai T, Newall F, Horton SB, Chiletti R, Johansen A, Best D, McKittrick J, Butt W, d'Udekem Y, MacLaren G, Linden MD, Ignjatovic V, Monagle P. Changes in von Willebrand Factor Multimers, Concentration, and Function During Pediatric Extracorporeal Membrane Oxygenation. Pediatr Crit Care Med 2023; 24:268-276. [PMID: 36602314 DOI: 10.1097/pcc.0000000000003152] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVES To investigate changes in von Willebrand factor (VWF) concentration, function, and multimers during pediatric extracorporeal membrane oxygenation (ECMO) and determine whether routine monitoring of VWF during ECMO would be useful in predicting bleeding. DESIGN Prospective observational study of pediatric ECMO patients from April 2017 to May 2019. SETTING The PICU in a large, tertiary referral pediatric ECMO center. PATIENTS Twenty-five neonates and children (< 18 yr) supported by venoarterial ECMO. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Arterial blood samples were collected within 24 hours pre-ECMO, daily for the first 5 days of ECMO, every second day until decannulation, and 24 hours post-ECMO. The STA R Max analyzer was used to measure VWF antigen (VWF:Ag) and ristocetin cofactor (VWF:RCo) activity. VWF collagen binding (VWF:CB) was measured using an enzyme-linked immunosorbent assay. VWF multimers were measured using the semi-automated Hydragel 11 VWF Multimer assay. Corresponding clinical data for each patient was also recorded. A total of 25 venoarterial ECMO patients were recruited (median age, 73 d; interquartile range [IQR], 3 d to 1 yr). The median ECMO duration was 4 days (IQR, 3-8 d) and 15 patients had at least one major bleed during ECMO. The percentage of high molecular weight multimers (HMWM) decreased and intermediate molecular weight multimers increased while patients were on ECMO, irrespective of a bleeding status. VWF:Ag increased and the VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag ratios decreased while patients were on ECMO compared with the baseline pre-ECMO samples and healthy children. CONCLUSIONS Neonates and children on ECMO exhibited a loss of HMWM and lower VWF:CB/VWF:Ag and VWF:RCo/VWF:Ag ratios compared with healthy children, irrespective of major bleeding occurring. Therefore, monitoring VWF during ECMO would not be useful in predicting bleeding in these patients and changes to other hemostatic factors should be investigated to further understand bleeding during ECMO.
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Affiliation(s)
- Suelyn Van Den Helm
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - Natasha Letunica
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Rebecca Barton
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
- Department of Clinical Haematology, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Cardiac Surgery, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Intensive Care, The Royal Children's Hospital, Melbourne, VIC, Australia
- Paediatric Intensive Care Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Critical Care, The University of Melbourne, Melbourne, VIC, Australia
- Department of Cardiac Surgery, Children's National Heart Institute, Washington, DC
- Cardiothoracic Intensive Care Unit, National University Health System, Singapore
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
- Kids Cancer Centre, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Asami Weaver
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Hui Ping Yaw
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Vasiliki Karlaftis
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - Conor McCafferty
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - Tengyi Cai
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - Fiona Newall
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
- Department of Clinical Haematology, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Cardiac Surgery, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Intensive Care, The Royal Children's Hospital, Melbourne, VIC, Australia
- Paediatric Intensive Care Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Critical Care, The University of Melbourne, Melbourne, VIC, Australia
- Department of Cardiac Surgery, Children's National Heart Institute, Washington, DC
- Cardiothoracic Intensive Care Unit, National University Health System, Singapore
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
- Kids Cancer Centre, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Stephen B Horton
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
- Department of Cardiac Surgery, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Roberto Chiletti
- Department of Intensive Care, The Royal Children's Hospital, Melbourne, VIC, Australia
- Paediatric Intensive Care Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Amy Johansen
- Department of Intensive Care, The Royal Children's Hospital, Melbourne, VIC, Australia
- Paediatric Intensive Care Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Derek Best
- Department of Intensive Care, The Royal Children's Hospital, Melbourne, VIC, Australia
- Paediatric Intensive Care Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Joanne McKittrick
- Department of Intensive Care, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Warwick Butt
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - Yves d'Udekem
- Department of Cardiac Surgery, Children's National Heart Institute, Washington, DC
| | - Graeme MacLaren
- Cardiothoracic Intensive Care Unit, National University Health System, Singapore
| | - Matthew D Linden
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Vera Ignjatovic
- Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - Paul Monagle
- Kids Cancer Centre, Sydney Children's Hospital, Randwick, NSW, Australia
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6
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Van Den Helm S, Yaw HP, Letunica N, Barton R, Weaver A, Newall F, Horton SB, Chiletti R, Johansen A, Best D, McKittrick J, Butt W, d'Udekem Y, MacLaren G, Linden MD, Ignjatovic V, Monagle P. Platelet Phenotype and Function Changes With Increasing Duration of Extracorporeal Membrane Oxygenation. Crit Care Med 2022; 50:1236-1245. [PMID: 35020670 DOI: 10.1097/ccm.0000000000005435] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To investigate platelet pathophysiology associated with pediatric extracorporeal membrane oxygenation (ECMO). DESIGN Prospective observational study of neonatal and pediatric ECMO patients from September 1, 2016, to December 31, 2019. SETTING The PICU in a large tertiary referral pediatric ECMO center. PATIENTS Eighty-seven neonates and children (< 18 yr) supported by ECMO. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Arterial blood samples were collected on days 1, 2, and 5 of ECMO and were analyzed by whole blood flow cytometry. Corresponding clinical data for each patient was also recorded. A total of 87 patients were recruited (median age, 65 d; interquartile range [IQR], 7 d to 4 yr). The median duration of ECMO was 5 days (IQR, 3-8 d) with a median length of stay in PICU and hospital of 18 days (IQR, 10-29 d) and 35 days (IQR, 19-75 d), respectively. Forty-two patients (48%) had at least one major bleed according to a priori determined definitions, and 12 patients (14%) had at least one thrombotic event during ECMO. Platelet fibrinogen receptor expression decreased (median fluorescence intensity [MFI], 29,256 vs 26,544; p = 0.0005), while von Willebrand Factor expression increased (MFI: 7,620 vs 8,829; p = 0.0459) from day 2 to day 5 of ECMO. Platelet response to agonist, Thrombin Receptor Activator Peptide 6, also decreased from day 2 to day 5 of ECMO, as measured by binding with anti-P-selectin, PAC-1 (binds activated GPIIb/IIIa), and anti-CD63 monoclonal antibodies (P-selectin area under the curve [AUC]: 63.46 vs 42.82, respectively, p = 0.0022; PAC-1 AUC: 93.75 vs 74.46, p = 0.0191; CD63 AUC: 55.69 vs 41.76, p = 0.0020). CONCLUSIONS The loss of platelet response over time may contribute to bleeding during ECMO. These novel insights may be useful in understanding mechanisms of bleeding in pediatric ECMO and monitoring platelet markers clinically could allow for prediction or early detection of bleeding and thrombosis.
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Affiliation(s)
- Suelyn Van Den Helm
- Haematology, Murdoch Children's Research Institute, Melbourne, VIC, Australia. Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia. Department of Clinical Haematology, The Royal Children's Hospital, Melbourne, VIC, Australia. Department of Cardiac Surgery, The Royal Children's Hospital, Melbourne, VIC, Australia. Department of Intensive Care, The Royal Children's Hospital, Melbourne, VIC, Australia. Paediatric Intensive Care Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia. Department of Cardiac Surgery, Children's National Heart Institute, Washington, DC. Cardiothoracic Intensive Care Unit, National University Health System, Singapore. School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia. Kids Cancer Centre, Sydney Children's Hospital, Randwick, NSW, Australia
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7
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Johnson BZ, Stevenson AW, Barrett LW, Fear MW, Wood FM, Linden MD. Platelets after burn injury - hemostasis and beyond. Platelets 2022; 33:655-665. [PMID: 34986759 DOI: 10.1080/09537104.2021.1981849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Burn injuries are common and often life-threatening trauma. With this trauma comes an interruption of normal hemostasis, with distinct impacts on platelets. Our interest in the relationships between burn injury and platelet function stems from two key perspectives: platelet function is a vital component of acute responses to injury, and furthermore the incidence of cardiovascular disease (CVD) is higher in burn survivors compared to the general population. This review explores the impact of burn injury on coagulation, platelet function, and the participation of platelets in immunopathology. Potential avenues of further research are explored, and consideration is given to what therapies may be appropriate for mediating post-burn thrombopathology.
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Affiliation(s)
- B Z Johnson
- Burn Injury Research Unit, University of Western Australia, Perth, Australia.,School of Biomedical Science, University of Western Australia, Perth, Australia
| | - A W Stevenson
- Burn Injury Research Unit, University of Western Australia, Perth, Australia.,School of Biomedical Science, University of Western Australia, Perth, Australia
| | - L W Barrett
- Burn Injury Research Unit, University of Western Australia, Perth, Australia.,Telethon Kids Institute, University of Western Australia, Perth, Australia
| | - M W Fear
- Burn Injury Research Unit, University of Western Australia, Perth, Australia.,School of Biomedical Science, University of Western Australia, Perth, Australia
| | - F M Wood
- Burn Injury Research Unit, University of Western Australia, Perth, Australia.,Burns Service of Western Australia, Wa Department of Health, Nedlands, Australia
| | - M D Linden
- School of Biomedical Science, University of Western Australia, Perth, Australia
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8
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Abstract
Platelets are small but very abundant blood cells that play a key role in hemostasis, contributing to thrombus formation at sites of injury. The ability of platelets to perform this function, as well as functions in immunity and inflammation, is dependent on the presence of cell surface glycoproteins and changes in their quantity and conformation after platelet stimulation. In this article, we describe the characterization of platelet surface markers and platelet function using platelet-specific fluorescent probes and flow cytometry. Unlike traditional platelet tests, immunophenotypic analysis of platelets by flow cytometry allows the analysis of platelet function in samples with very low platelet counts as often encountered in clinical situations. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Immunophenotyping of platelet surface receptors Alternate Protocol: Fix-first method for immunophenotyping of platelet surface receptors Basic Protocol 2: Determination of platelet activation using P-selectin expression and/or PAC1 binding Basic Protocol 3: Determination of procoagulant platelets using annexin V binding or antibodies specific for coagulation factor V/Va or X/Xa Support Protocol: Preparation of isolated platelets.
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Affiliation(s)
- Benjamin E J Spurgeon
- Center for Platelet Research Studies, Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Harvard Medical School, Boston, Massachusetts
| | - Matthew D Linden
- School of Biomedical Sciences, University of Western Australia, Perth, Australia
| | - Alan D Michelson
- Center for Platelet Research Studies, Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Harvard Medical School, Boston, Massachusetts
| | - Andrew L Frelinger
- Center for Platelet Research Studies, Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Harvard Medical School, Boston, Massachusetts
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9
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Johnson BZ, McAlister S, McGuire HM, Palanivelu V, Stevenson A, Richmond P, Palmer DJ, Metcalfe J, Prescott SL, Wood FM, Fazekas de St Groth B, Linden MD, Fear MW, Fear VS. Corrigendum: Pediatric Burn Survivors Have Long-Term Immune Dysfunction With Diminished Vaccine Response. Front Immunol 2020; 11:598646. [PMID: 33163008 PMCID: PMC7581988 DOI: 10.3389/fimmu.2020.598646] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 12/05/2022] Open
Affiliation(s)
- Blair Z Johnson
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Sonia McAlister
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, WA, Australia
| | - Helen M McGuire
- Ramaciotti Facility for Human Systems Biology and the Charles Perkins Centre, Discipline of Pathology, The University of Sydney, Sydney, NSW, Australia
| | | | - Andrew Stevenson
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Peter Richmond
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, WA, Australia
| | - Debra J Palmer
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Centre for Allergy and Immunology Research, Telethon Kids Institute, Perth, WA, Australia
| | - Jessica Metcalfe
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Centre for Allergy and Immunology Research, Telethon Kids Institute, Perth, WA, Australia
| | - Susan L Prescott
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Centre for Allergy and Immunology Research, Telethon Kids Institute, Perth, WA, Australia
| | - Fiona M Wood
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Department of Health WA, Perth, WA, Australia
| | - Barbara Fazekas de St Groth
- Ramaciotti Facility for Human Systems Biology and the Charles Perkins Centre, Discipline of Pathology, The University of Sydney, Sydney, NSW, Australia
| | - Matthew D Linden
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Mark W Fear
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Vanessa S Fear
- Genetic and Rare Diseases, Telethon Kids Institute, Perth, WA, Australia
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10
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Johnson BZ, McAlister S, McGuire HM, Palanivelu V, Stevenson A, Richmond P, Palmer DJ, Metcalfe J, Prescott SL, Wood FM, Fazekas de St Groth B, Linden MD, Fear MW, Fear VS. Pediatric Burn Survivors Have Long-Term Immune Dysfunction With Diminished Vaccine Response. Front Immunol 2020; 11:1481. [PMID: 32793203 PMCID: PMC7385079 DOI: 10.3389/fimmu.2020.01481] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/08/2020] [Indexed: 01/04/2023] Open
Abstract
Epidemiological studies have demonstrated that survivors of acute burn trauma are at long-term increased risk of developing a range of morbidities. The mechanisms underlying this increased risk remain unknown. This study aimed to determine whether burn injury leads to sustained immune dysfunction that may underpin long-term morbidity. Plasma and peripheral blood mononuclear cells were collected from 36 pediatric burn survivors >3 years after a non-severe burn injury (<10% total body surface area) and from age/sex-matched non-injured controls. Circulating cytokine and vaccine antibody levels were assessed using multiplex immunoassays and cell profiles compared using a panel of 40 metal-conjugated antibodies and mass cytometry. TNF-α (1.31-fold change from controls), IL-2 (1.18-fold), IL-7 (1.63-fold), and IFN-γ (1.18-fold) were all significantly elevated in the burn cohort. Additionally, burn survivors demonstrated diminished antibody responses to the diphtheria, tetanus, and pertussis vaccine antigens. Comparisons between groups using unsupervised clustering identified differences in proportions of clusters within T-cells, B-cells and myeloid cells. Manual gating confirmed increased memory T-regulatory and central memory CD4+ T-cells, with altered expression of T-cell, B-cell, and dendritic cell markers. Conclusions: This study demonstrates a lasting change to the immune profile of pediatric burn survivors, and highlights the need for further research into post-burn immune suppression and regulation.
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Affiliation(s)
- Blair Z Johnson
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Sonia McAlister
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, WA, Australia
| | - Helen M McGuire
- Ramaciotti Facility for Human Systems Biology and the Charles Perkins Centre, Discipline of Pathology, The University of Sydney, Sydney, NSW, Australia
| | | | - Andrew Stevenson
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Peter Richmond
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, WA, Australia
| | - Debra J Palmer
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Centre for Allergy and Immunology Research, Telethon Kids Institute, Perth, WA, Australia
| | - Jessica Metcalfe
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Centre for Allergy and Immunology Research, Telethon Kids Institute, Perth, WA, Australia
| | - Susan L Prescott
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Centre for Allergy and Immunology Research, Telethon Kids Institute, Perth, WA, Australia
| | - Fiona M Wood
- School of Medicine, The University of Western Australia, Perth, WA, Australia.,Department of Health WA, Perth, WA, Australia
| | - Barbara Fazekas de St Groth
- Ramaciotti Facility for Human Systems Biology and the Charles Perkins Centre, Discipline of Pathology, The University of Sydney, Sydney, NSW, Australia
| | - Matthew D Linden
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Mark W Fear
- School of Biomedical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Vanessa S Fear
- Genetic and Rare Diseases, Telethon Kids Institute, Perth, WA, Australia
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11
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Guo BB, Linden MD, Fuller KA, Phillips M, Mirzai B, Wilson L, Chuah H, Liang J, Howman R, Grove CS, Malherbe JA, Leahy MF, Allcock RJ, Erber WN. Platelets in myeloproliferative neoplasms have a distinct transcript signature in the presence of marrow fibrosis. Br J Haematol 2019; 188:272-282. [PMID: 31426129 DOI: 10.1111/bjh.16152] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/20/2019] [Indexed: 01/10/2023]
Abstract
Marrow fibrosis is a significant complication of myeloproliferative neoplasms (MPN) that affects up to 20% of patients and is associated with a poor prognosis. The pathological processes that lead to fibrotic progression are not well understood, but megakaryocytes have been implicated in the process. The aim of this study was to determine whether platelets, derived from megakaryocytes, have transcriptomic alterations associated with fibrosis. Platelets from MPN patients with and without fibrosis and non-malignant control individuals were assessed using next generation sequencing. Results from the initial training cohort showed discrete changes in platelet transcripts in the presence of marrow fibrosis. We identified more than 1000 differentially expressed transcripts from which a putative 3-gene fibrotic platelet signature (CCND1, H2AX [previously termed H2AFX] and CEP55) could be identified. This fibrosis-associated signature was assessed blinded on platelets from an independent test MPN patient cohort. The 3-gene signature was able to discriminate between patients with and without marrow fibrosis with a positive predictive value of 71% (93% specificity, 71% sensitivity). This demonstrates that assessment of dysregulated transcripts in platelets may be a useful monitoring tool in MPN to identify progression to marrow fibrosis. Further, sequential monitoring could have clinical applications for early prediction of progression to fibrosis.
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Affiliation(s)
- Belinda B Guo
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia
| | - Matthew D Linden
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia
| | - Kathryn A Fuller
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,PathWest Laboratory Medicine, Nedlands, WA, Australia
| | - Michael Phillips
- Centre for Medical Research, University of Western Australia, Crawley, WA, Australia
| | - Bob Mirzai
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,PathWest Laboratory Medicine, Nedlands, WA, Australia
| | - Lynne Wilson
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,PathWest Laboratory Medicine, Nedlands, WA, Australia
| | - Hun Chuah
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,Royal Perth Hospital, Department of Health Western Australia, Perth, WA, Australia
| | - James Liang
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,Sir Charles Gairdner Hospital, Department of Health Western Australia, Nedlands, WA, Australia
| | - Rebecca Howman
- Sir Charles Gairdner Hospital, Department of Health Western Australia, Nedlands, WA, Australia
| | - Carolyn S Grove
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,PathWest Laboratory Medicine, Nedlands, WA, Australia.,Sir Charles Gairdner Hospital, Department of Health Western Australia, Nedlands, WA, Australia
| | - Jacques A Malherbe
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,Medical School, University of Western Australia, Crawley, WA, Australia
| | - Michael F Leahy
- PathWest Laboratory Medicine, Nedlands, WA, Australia.,Royal Perth Hospital, Department of Health Western Australia, Perth, WA, Australia.,Medical School, University of Western Australia, Crawley, WA, Australia
| | - Richard J Allcock
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,PathWest Laboratory Medicine, Nedlands, WA, Australia
| | - Wendy N Erber
- School of Biomedical Sciences, University of Western Australia, Crawley, WA, Australia.,PathWest Laboratory Medicine, Nedlands, WA, Australia.,Medical School, University of Western Australia, Crawley, WA, Australia
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12
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Haynes A, Linden MD, Robey E, Watts GF, Barrett PHR, Naylor LH, Green DJ. Acute Impact of Different Exercise Modalities on Arterial and Platelet Function. Med Sci Sports Exerc 2019; 50:785-791. [PMID: 29240651 DOI: 10.1249/mss.0000000000001505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE Acute coronary syndromes and ischemic stroke are associated with arterial events involving platelets, the endothelium, and atherosclerosis. Although regular physical activity is associated with lower risk of cardiovascular events and mortality, risk is transiently increased during and immediately after participation in an acute bout of exercise. No previous study has investigated the acute impact of exercise on platelet activation and arterial function in the same participants; it is also unknown if responses are dependent on exercise modality. We hypothesized that commonly adopted, yet physiologically distinct, modalities of exercise ("aerobic" vs "resistance") have differing effects on in vivo platelet activation and conduit artery diameter. METHODS Eight apparently healthy middle-age (53.5 ± 1.6 yr) male subjects took part in four 30-min experimental interventions (aerobic exercise, resistance exercise, combined aerobic/resistance exercise, or no-exercise), in random order. Blood samples were collected, and the measurement of brachial artery diameter by ultrasound was performed before, immediately after, and 1 h after each intervention. Platelet activation was determined by the positive binding of antibodies to surface receptors exposed on activated platelets (anti-CD62P and PAC-1). RESULTS Brachial artery diameter increased immediately after all three exercise modalities (P < 0.001) and remained above preexercise levels 1 h after resistance exercise and after combined aerobic/resistance exercise. No changes were observed in markers of in vivo platelet activation with any experimental protocol. CONCLUSIONS These data suggest that postexercise enhancement in arterial function may mitigate the acute impact of exercise on platelet activation.
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Affiliation(s)
- Andrew Haynes
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA
| | - Matthew D Linden
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA
| | - Elisa Robey
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA
| | - Gerald F Watts
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA.,School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA
| | - P Hugh R Barrett
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA
| | - Louise H Naylor
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA.,School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA.,School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Crawley, WA, AUSTRALIA
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13
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Abstract
Antiplatelet agents are used for the prevention and treatment of thromboembolic disease in an increasingly complex population of pediatric patients. Despite their importance for clinical outcome, there is no consensus on the most effective monitoring strategies. This review describes the current state of knowledge focusing on antiplatelet therapy monitoring in children. The authors searched five databases (PubMed-NCBI, MEDLINE-OVID, SCOPUS-Elsevier, ScienceDirect, and Cochrane) from January 2000 to October 2017 using keywords selected a priori. Identified articles were sorted according to the antiplatelet agents administered, methods of antiplatelet monitoring, and outcome measures. Twenty studies were included, with 14 cohort studies, 3 randomized controlled trials, and 3 cross-sectional studies. Eleven different antiplatelet monitoring tools were used, with the most common being Light Transmission Aggregometry, Urinary Thromboxane, Thromboelastography with Platelet Mapping, and VerifyNow. In the majority of studies, antiplatelet therapy monitoring was used to describe adequacy or responsiveness to treatment based on laboratory cut-off values, which were not uniform and sourced from adult studies or extrapolated from test manuals. Several studies evaluated monitoring related to clinical outcome or adjusted therapy to reach predefined therapeutic targets. There was no single laboratory method found to be distinctly better for monitoring antiplatelet treatment. Associations between laboratory assays and clinical outcomes or assays and gold standard measurements were highly inconsistent. The current literature lacks consensus on clinical benefits and measurable effects of monitoring antiplatelet therapy in pediatric patients. This review highlights important areas for research required to determine the value of antiplatelet therapy monitoring in children.
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Affiliation(s)
- Joanna Yilin Huang
- School of Clinical Sciences, Monash University, Clayton, Victoria, Australia.,Hematology Research Group, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Clinical Hematology, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Diajeng Ayesha Soeharto
- Faculty of Medicine, Dentistry, and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia.,Faculty of Medicine, University of Indonesia, Jakarta, Indonesia
| | - Ivan Damara
- Faculty of Medicine, Dentistry, and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia.,Faculty of Medicine, University of Indonesia, Jakarta, Indonesia
| | - Vera Ignjatovic
- Hematology Research Group, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Pediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Matthew D Linden
- School of Biomedical Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Paul Monagle
- Hematology Research Group, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Clinical Hematology, Royal Children's Hospital, Parkville, Victoria, Australia.,Department of Pediatrics, The University of Melbourne, Parkville, Victoria, Australia
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14
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Haynes A, Linden MD, Robey E, Naylor LH, Ainslie PN, Cox KL, Lautenschlager NT, Green DJ. Beneficial impacts of regular exercise on platelet function in sedentary older adults: evidence from a randomized 6-mo walking trial. J Appl Physiol (1985) 2018; 125:401-408. [PMID: 29648514 DOI: 10.1152/japplphysiol.00079.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Platelet activation, including the formation of monocyte platelet aggregates (MPAs), contributes to atherosclerosis, thrombus formation, and acute coronary syndromes. Regular participation in exercise can lower cardiovascular risk, but little is known regarding the impact of exercise training on platelet function. We investigated the effect of 6 mo of walking exercise on platelet function in sedentary older adults without significant cardiovascular disease. Twenty-seven participants were randomly allocated to 6 mo of either: no-exercise ( n = 13) or 3 × 50 min/wk of supervised center-based walking ( n = 14). Circulating and agonist-induced MPAs were assessed using flow cytometry before [ month 0 (0M)] and after [ month 6 (6M)] the intervention. Circulating MPAs increased from 0M (3.7 ± 1.0%) to 6M (4.7 ± 1.6%) in the no-exercise group ( P = 0.009), whereas a nonsignificant decrease was observed in the walking group (0M 4.3 ± 1.7 vs. 6M 3.7 ± 1.2 %, P = 0.052). The change in MPAs between groups was significant ( P = 0.001). There were no differences between groups in platelet responses to agonists across the interventions (all P > 0.05). Collectively, these data suggest that the absence of regular exercise may increase MPAs, which are cellular mediators involved in atherosclerosis, while regular walking inhibits such increases. The thrombotic function of platelets appears to be relatively unaltered by exercise training. This study provides novel data related to the cardioprotective effects associated with participation in exercise. NEW & NOTEWORTHY Monocyte-platelet aggregates contribute to atherosclerosis and exercise can lower cardiovascular risk. This is the first study to discover that a lack of regular physical activity is associated with increased monocyte-platelet aggregates over a 6-mo intervention period. In contrast, walking exercise inhibits increased monocyte-platelet aggregates in the circulation. This study highlights a novel pathway by which regular participation in exercise exerts its cardioprotective effects.
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Affiliation(s)
- Andrew Haynes
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia , Crawley, Western Australia
| | - Matthew D Linden
- School of Biomedical Sciences, The University of Western Australia , Crawley, Western Australia
| | - Elisa Robey
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia , Crawley, Western Australia
| | - Louise H Naylor
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia , Crawley, Western Australia
| | - Philip N Ainslie
- Centre for Heart, Lund and Vascular Health, School of Health and Exercise Science, The University of British Columbia , Kelowna, British Columbia , Canada
| | - Kay L Cox
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia , Crawley, Western Australia.,School of Medicine (Royal Perth Hospital Unit), The University of Western Australia , Crawley, Western Australia
| | - Nicola T Lautenschlager
- Academic Unit for Psychiatry of Old Age, Department of Psychiatry, The University of Melbourne , Victoria , Australia.,NorthWestern Mental Health, Melbourne Health, Parkville, Victoria , Australia.,School of Clinical Neurosciences and the Western Australia Centre for Health and Ageing, The University of Western Australia , Crawley, Western Australia
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia , Crawley, Western Australia.,Principal Research Fellow, National Health and Medical Research Council , Australia
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15
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Haynes A, Linden MD, Robey E, Naylor LH, Cox KL, Lautenschlager NT, Green DJ. Relationship between monocyte-platelet aggregation and endothelial function in middle-aged and elderly adults. Physiol Rep 2017; 5:e13189. [PMID: 28533260 PMCID: PMC5449553 DOI: 10.14814/phy2.13189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 02/09/2017] [Indexed: 01/22/2023] Open
Abstract
Low-grade inflammation, endothelial dysfunction, and platelet hyper-reactivity to agonists are associated with an increased risk of cardiovascular events. In vitro and animal studies infer an inverse mechanistic relationship between platelet activation and the production of endothelium-derived nitric oxide and prostacyclin. This concept is supported by evidence of an inverse relationship between endothelial function and platelet activation in high-risk cardiac patients. The aim of this study was to investigate what relationship, if any, exists between platelet and endothelial function in healthy, middle-aged, and elderly adults. In 51 participants (18 male, 33 post menopausal female), endothelial function was assessed by flow-mediated dilation (FMD). Platelet function was assessed by flow cytometric determination of glycoprotein IIb/IIIa activation (measured by PAC-1 binding), granule exocytosis (measured by surface P-selectin expression), and monocyte-platelet aggregates (MPAs), with and without stimulation by canonical platelet agonists adenosine diphosphate (ADP), arachidonic acid (AA), and collagen. Correlation analysis indicated there was no significant (all P => 0.05) relationship between FMD and any marker of in vivo platelet activation (MPAs R = 0.193, PAC-1 R = -0.113, anti-CD62P R = -0.078) or inducible platelet activation by ADP (MPA R = -0.128, anti-CD62P R = -0.237), AA (MPA R = -0.122, PAC-1 R = -0.045, anti-CD62P R = -0.142), or collagen (MPA R = 0.136, PAC-1 R = 0.174, anti-CD62P R = -0.077). Our findings contrast with two previous studies performed in high-risk cardiac patients, which reported inverse relationships between platelet activation and endothelial function, suggesting that some compensatory redundancy may exist in the relationship between platelet and endothelial function in preclinical populations.
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Affiliation(s)
- Andrew Haynes
- School of Sport ScienceExercise and HealthUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Matthew D. Linden
- School of Pathology and Laboratory MedicineUniversity of Western AustraliaCrawleyWestern Australia
| | - Elisa Robey
- School of Sport ScienceExercise and HealthUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Louise H. Naylor
- School of Sport ScienceExercise and HealthUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Kay L. Cox
- School of Sport ScienceExercise and HealthUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
- School of Medicine and Pharmacology (Royal Perth Hospital Unit)University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Nicola T. Lautenschlager
- Academic Unit for Psychiatry of Old AgeDepartment of PsychiatryUniversity of MelbourneMelbourneVictoriaAustralia
- NorthWestern Mental HealthMelbourne HealthParkvilleVictoriaAustralia
- School of Clinical Neurosciences and the Western Australia Centre for Health and AgeingUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Daniel J. Green
- School of Sport ScienceExercise and HealthUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
- Research Institute for Sport and Exercise ScienceLiverpool John Moores UniversityLiverpoolUnited Kingdom
- Principal Research FellowNational Health and Medical Research CouncilCanberraAustralian Capital TerritoryAustralia
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16
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Haynes A, Linden MD, Chasland LC, Nosaka K, Maiorana A, Dawson EA, Dembo LH, Naylor LH, Green DJ. Acute impact of conventional and eccentric cycling on platelet and vascular function in patients with chronic heart failure. J Appl Physiol (1985) 2017; 122:1418-1424. [PMID: 28302709 DOI: 10.1152/japplphysiol.01057.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/23/2017] [Accepted: 03/13/2017] [Indexed: 11/22/2022] Open
Abstract
Evidence-based guidelines recommend exercise therapy for patients with chronic heart failure (CHF). Such patients have increased atherothrombotic risk. Exercise can transiently increase platelet activation and reactivity and decrease vascular function in healthy participants, although data in CHF are scant. Eccentric (ECC) cycling is a novel exercise modality that may be particularly suited to patients with CHF, but the acute impacts of ECC cycling on platelet and vascular function are currently unknown. Our null hypothesis was that ECC and concentric (CON) cycling, performed at matched external workloads, would not induce changes in platelet or vascular function in patients with CHF. Eleven patients with heart failure with reduced ejection fraction (HFrEF) took part in discrete bouts of ECC and CON cycling. Before and immediately after exercise, vascular function was assessed by measuring diameter and flow-mediated dilation (FMD) of the brachial artery. Platelet function was measured by the flow cytometric determination of glycoprotein IIb/IIIa activation and granule exocytosis in the presence and absence of platelet agonists. ECC cycling increased baseline artery diameter (pre: 4.0 ± 0.8 mm vs. post: 4.2 ± 0.7 mm; P = 0.04) and decreased FMD%. When changes in baseline artery diameter were accounted for, the decrease in FMD post-ECC cycling was no longer significant. No changes were apparent after CON. Neither ECC nor CON cycling resulted in changes to any platelet-function measures (all P > 0.05). These results suggest that both ECC and CON cycling, at a moderate intensity and short duration, can be performed by patients with HFrEF without detrimental impacts on vascular or platelet function.NEW & NOTEWORTHY This is the first evidence to indicate that eccentric (ECC) cycling can be performed relatively safely by patients with chronic heart failure (CHF), as it did not result in impaired vascular or platelet function compared with conventional cycling. This is important, as acute exercise can transiently increase atherothrombotic risk, and ECC cycling is a novel exercise modality that may be particularly suited to patients with CHF.
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Affiliation(s)
- Andrew Haynes
- School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia
| | - Matthew D Linden
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, Western Australia
| | - Lauren C Chasland
- School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia
| | - Kazunori Nosaka
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia
| | - Andrew Maiorana
- School of Physiotherapy and Exercise Science, Curtin University, Perth, Western Australia.,Allied Health Department, Fiona Stanley Hospital, Perth, Western Australia
| | - Ellen A Dawson
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom; and
| | - Lawrence H Dembo
- Advanced Heart Failure and Cardiac Transplantation Unit, Fiona Stanley Hospital, Perth, Western Australia
| | - Louise H Naylor
- School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia.,Allied Health Department, Fiona Stanley Hospital, Perth, Western Australia
| | - Daniel J Green
- School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia; .,Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom; and
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17
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Hui H, Fuller KA, Erber WN, Linden MD. Imaging flow cytometry in the assessment of leukocyte-platelet aggregates. Methods 2017; 112:46-54. [DOI: 10.1016/j.ymeth.2016.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 01/31/2023] Open
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Haynes A, Linden MD, Robey E, Watts GF, Barrett H, Naylor LH, Green DJ. Impact of commonly prescribed exercise interventions on platelet activation in physically inactive and overweight men. Physiol Rep 2016; 4:4/20/e12951. [PMID: 27798349 PMCID: PMC5099958 DOI: 10.14814/phy2.12951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 01/13/2023] Open
Abstract
The exercise paradox infers that, despite the well‐established cardioprotective effects of repeated episodic exercise (training), the risk of acute atherothrombotic events may be transiently increased during and soon after an exercise bout. However, the acute impact of different exercise modalities on platelet function has not previously been addressed. We hypothesized that distinct modalities of exercise would have differing effects on in vivo platelet activation and reactivity to agonists which induce monocyte‐platelet aggregate (MPA) formation. Eight middle‐aged (53.5 ± 1.6 years) male participants took part in four 30 min experimental interventions (aerobic AE, resistance RE, combined aerobic/resistance exercise CARE, or no‐exercise NE), in random order. Blood samples were collected before, immediately after, and 1 h after each intervention, and incubated with one of three agonists of physiologically/clinically relevant pathways of platelet activation (thrombin receptor activating peptide‐6 TRAP, arachidonic acid AA, and cross‐linked collagen‐related peptide xCRP). In the presence of AA, TRAP, and xCRP, both RE and CARE evoked increases in MPAs immediately post‐exercise (P < 0.01), whereas only AA significantly increased MPAs immediately after AE (P < 0.01). These increases in platelet activation post‐exercise were transient, as responses approached pre‐exercise levels by 1 h. These are the first data to suggest that exercise involving a resistance component in humans may transiently increase platelet‐mediated thrombotic risk more than aerobic modalities.
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Affiliation(s)
- Andrew Haynes
- School of Sport Science, Exercise and Health, University of Western Australia, Crawley, Western Australia, Australia
| | - Matthew D Linden
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia
| | - Elisa Robey
- School of Sport Science, Exercise and Health, University of Western Australia, Crawley, Western Australia, Australia
| | - Gerald F Watts
- Cardiometabolic Services, Department of Cardiology, Royal Perth Hospital, Western Australia, Australia
| | - Hugh Barrett
- School of Medicine and Pharmacology Royal Perth Hospital Unit University of Western Australia, Crawley, Western Australia, Australia
| | - Louise H Naylor
- School of Sport Science, Exercise and Health, University of Western Australia, Crawley, Western Australia, Australia
| | - Daniel J Green
- School of Sport Science, Exercise and Health, University of Western Australia, Crawley, Western Australia, Australia .,Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom.,Principal Research Fellow, National Health and Medical Research Council, Canberra, ACT, Australia
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Fuller K, Linden MD, Lee-Pullen T, Fragall C, Erber WN, Röhrig KJ. An active, collaborative approach to learning skills in flow cytometry. Adv Physiol Educ 2016; 40:176-185. [PMID: 27068992 DOI: 10.1152/advan.00002.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 01/27/2016] [Indexed: 06/05/2023]
Abstract
Advances in science education research have the potential to improve the way students learn to perform scientific interpretations and understand science concepts. We developed active, collaborative activities to teach skills in manipulating flow cytometry data using FlowJo software. Undergraduate students were given compensated clinical flow cytometry listmode output (FCS) files and asked to design a gating strategy to diagnose patients with different hematological malignancies on the basis of their immunophenotype. A separate cohort of research trainees was given uncompensated data files on which they performed their own compensation, calculated the antibody staining index, designed a sequential gating strategy, and quantified rare immune cell subsets. Student engagement, confidence, and perceptions of flow cytometry were assessed using a survey. Competency against the learning outcomes was assessed by asking students to undertake tasks that required understanding of flow cytometry dot plot data and gating sequences. The active, collaborative approach allowed students to achieve learning outcomes not previously possible with traditional teaching formats, for example, having students design their own gating strategy, without forgoing essential outcomes such as the interpretation of dot plots. In undergraduate students, favorable perceptions of flow cytometry as a field and as a potential career choice were correlated with student confidence but not the ability to perform flow cytometry data analysis. We demonstrate that this new pedagogical approach to teaching flow cytometry is beneficial for student understanding and interpretation of complex concepts. It should be considered as a useful new method for incorporating complex data analysis tasks such as flow cytometry into curricula.
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Affiliation(s)
- Kathryn Fuller
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia
| | - Matthew D Linden
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia; Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, Western Australia, Australia
| | - Tracey Lee-Pullen
- Bendat Family Comprehensive Cancer Centre, St John of God Subiaco Hospital, Perth, Western Australia, Australia; and School of Surgery, The University of Western Australia, Crawley, Western Australia, Australia
| | - Clayton Fragall
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia
| | - Wendy N Erber
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia
| | - Kimberley J Röhrig
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia;
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Burchall GF, Piva TJ, Linden MD, Gibson-Helm ME, Ranasinha S, Teede HJ. Comprehensive Assessment of the Hemostatic System in Polycystic Ovarian Syndrome. Semin Thromb Hemost 2015; 42:55-62. [PMID: 26595150 DOI: 10.1055/s-0035-1564837] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Polycystic ovarian syndrome (PCOS) affects 12 to 19% of women and has reproductive and metabolic features (endothelial dysfunction, increased diabetes, and cardiovascular risk factors). It also appears to have altered coagulation and fibrinolysis with a prothrombotic state with epidemiological evidence of increased venous thromboembolism. We aimed to comprehensively assess hemostasis in women with PCOS versus control women. In an established case-control cohort of lean, overweight, and obese women with (n = 107) and without PCOS (n = 67), with existing measures of plasminogen activator inhibitor 1 (PAI-1), asymmetric dimethylarginine (ADMA), hormonal, and metabolic markers, we also assessed prothrombin fragments 1 and 2 (PF1 & 2), plasminogen, tissue plasminogen activator (tPA), and thrombin generation (TG). Higher levels of ADMA (0.70 vs. 0.39 µmol/L, p < 0.01), PAI-1 (4.80 vs. 3.66 U/mL, p < 0.01), and plasminogen (118.39 vs. 108.46%, p < 0.01) were seen in PCOS versus controls, and persisted after adjustment for age and body mass index (BMI). PF1 & 2 was marginally lower (180.0 vs. 236.0 pmol/L, p = 0.05), whereas tPA and TG were not different between groups, after adjustment for age and BMI. Significant relationships were observed between hormonal and metabolic factors with ADMA and PAI-1. We demonstrate impaired fibrinolysis in PCOS. In the context of abnormal endothelial function and known hormonal and metabolic abnormalities, this finding may underpin an increased risk of cardiovascular disease and venous thrombosis in PCOS.
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Affiliation(s)
- Genia F Burchall
- School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Terrence J Piva
- School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Matthew D Linden
- School of Pathology and Laboratory Medicine, University of Western Australia, Nedlands, Australia
| | - Melanie E Gibson-Helm
- School of Public Health and Preventive Medicine, Monash University, Clayton, Victoria, Australia
| | - Sanjeeva Ranasinha
- School of Public Health and Preventive Medicine, Monash University, Clayton, Victoria, Australia
| | - Helena J Teede
- School of Public Health and Preventive Medicine, Monash University, Clayton, Victoria, Australia
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21
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Hui H, Fuller K, Erber WN, Linden MD. Measurement of monocyte-platelet aggregates by imaging flow cytometry. Cytometry A 2014; 87:273-8. [PMID: 25514846 DOI: 10.1002/cyto.a.22587] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 10/06/2014] [Accepted: 10/15/2014] [Indexed: 11/11/2022]
Abstract
Platelets are subcellular blood elements with a well-established role in haemostasis. Upon activation platelets express P-Selectin (CD62P) on the cell membrane and bind to P-Selectin glycoprotein ligand 1 expressing monocytes, influencing them toward a pro-adhesive and inflammatory phenotype. It is well established that elevated circulating monocyte-platelet aggregates (MPAs) are linked to atherothrombosis in high risk patients. However, whole blood flow cytometry (FCM) has recently shown that circulating MPAs may also occur in the absence of platelet activation, particularly in healthy children. A potential limitation of conventional FCM is the potential for coincident events to resemble monocyte platelet aggregates. Here we report a novel imaging cytometry approach to further characterize monocyte-platelet aggregate formation by P-Selectin dependent and P-Selectin independent mechanisms and distinguish circulating MPAs from coincidental events. Monocytes were identified by expression of the lipopolysachharide receptor (CD14 BV421), while platelets were identified by expression of the glycoprotein Ib (CD42b APC). Differentiation of P-Selectin dependent and P-Selectin independent binding was achieved with AF488 labeled CD62P. Overall analysis of circulating and in vitro generated MPAs by conventional and imaging cytometry methods showed very strong correlation (r(2) = >0.99, P < 0.01). The Bland-Altman bias of -1.72 was not significantly different to zero. However, when measuring only P-Selectin negative MPAs, a lack of correlation (r(2) = 0.27, P = n.s.) likely reflects better discrimination of coincidence events using imaging cytometry. Our data demonstrate that IFC is more accurate in enumerating MPAs than conventional FCM, which over-estimates the number of MPAs due to the presence of coincident events.
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Affiliation(s)
- Henry Hui
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth, Australia; School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Australia
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Yip C, Linden MD, Attard C, Monagle P, Ignjatovic V. Platelets from children are hyper-responsive to activation by thrombin receptor activator peptide and adenosine diphosphate compared to platelets from adults. Br J Haematol 2014; 168:526-32. [PMID: 25266817 DOI: 10.1111/bjh.13153] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 08/29/2014] [Indexed: 10/24/2022]
Abstract
Platelets are crucial subcellular elements of haemostasis at sites of vascular injury and are also known to be immune mediators in pathological thrombosis. Despite the integral role of platelets in many disease processes, there is very little information available on platelet function and response to agonists in healthy children. We recently reported important differences in the interaction of platelets with monocytes in the circulation, including increased formation of monocyte-platelet aggregates (MPAs) without concomitant increase in P-selectin expression. Our current study investigates parameters of platelet activation (PAC-1 binding and P-selectin expression) and MPA formation in response to a range of physiologically relevant platelet agonists in healthy children compared to healthy adults. All parameters were significantly higher in children in response to sub-maximal concentrations of thrombin receptor activator peptide and adenosine diphosphate, reflecting an age-specific difference in agonist-stimulated platelet reactivity in children. The results of our study challenge the general assumption that platelet reactivity in children is similar to adults. This finding is fundamental to investigating the role of platelets in diseases of childhood and pathogenesis of adult-based diseases that have their origins in childhood. Our findings underscore the need for age-specific reference ranges for platelet function in children rather than extrapolation from adult data.
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Affiliation(s)
- Christina Yip
- Haematology Research, Murdoch Childrens Research Institute, Melbourne, Vic., Australia; The University of Melbourne, Parkville, Vic., Australia
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Mosawy S, Jackson DE, Woodman OL, Linden MD. The flavonols quercetin and 3',4'-dihydroxyflavonol reduce platelet function and delay thrombus formation in a model of type 1 diabetes. Diab Vasc Dis Res 2014; 11:174-81. [PMID: 24623318 DOI: 10.1177/1479164114524234] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Diabetes is associated with increased cardiovascular risk. We have recently shown that the naturally occurring flavonol quercetin (Que) or the synthetic flavonol 3',4'-dihydroxyflavonol (DiOHF) inhibits platelet function and delays thrombus formation in healthy mice. Therefore, the aim of this study was to investigate the effect of Que or DiOHF treatment on platelet function and ferric chloride-induced carotid artery thrombosis in a mouse model of type 1 diabetes. Diabetic mice treated with Que or DiOHF maintained blood flow at a significantly higher level than untreated diabetic mice at the end of the recording period. In addition, treatment with Que or DiOHF significantly reduced diabetes-induced platelet hyper-aggregability in response to platelet agonist stimulation. Furthermore, treatment with Que or DiOHF significantly inhibited dense, but not alpha, granule exocytosis in diabetic and control mice. Our demonstration that flavonols delay thrombus formation in diabetes suggests a potential clinical role for these compounds in anti-platelet therapy.
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Affiliation(s)
- Sapha Mosawy
- School of Medical Sciences, RMIT University, Melbourne, VIC, Australia
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Mosawy S, Jackson DE, Woodman OL, Linden MD. Treatment with quercetin and 3',4'-dihydroxyflavonol inhibits platelet function and reduces thrombus formation in vivo. J Thromb Thrombolysis 2014; 36:50-7. [PMID: 23070586 DOI: 10.1007/s11239-012-0827-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Flavonols are polyphenolic compounds with reported cardiovascular benefits and have been shown to exhibit antiplatelet properties in vitro. While some studies have shown inhibition of platelet aggregation following dietary supplementation with flavonol rich foods, few studies have assessed the ability of flavonols to inhibit platelet mediated thrombus generation in vivo. Furthermore, the duration of benefit and the influence of different dosing regimens remain unclear. In this study we investigate the ability of two structurally related flavonols; quercetin (Que) and 3',4'-dihydroxyflavonol (DiOHF) to inhibit platelet aggregation, platelet granule exocytosis and vessel occlusion in a well characterized mouse model of platelet mediated arterial thrombosis. We investigated the effect of a single 6 mg/kg intravenous bolus and daily 6 mg/kg intraperitoneal doses over seven consecutive days. Carotid artery blood flow after injury was better maintained in mice treated with both Que and DiOHF when compared to the vehicle for both dosage regimens. This improved blood flow corresponded to inhibition of platelet aggregation and platelet dense granule exocytosis following chemical stimulation of PAR4. We therefore provide evidence of inhibition of platelet-mediated arterial thrombosis by flavonols in vivo, and demonstrate that this effect persists for at least 24 h after the last intraperitoneal dose. These data suggest a potential clinical role for flavonols as anti-platelet therapy.
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Affiliation(s)
- S Mosawy
- School of Medical Sciences, RMIT University, Melbourne, VIC, Australia
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25
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Selva Raj I, Westfold BA, Shield AJ, Linden MD, Bird SR. The Acute Effects of Eccentrically-Biased Versus Conventional Weight Training in Older Adults: A Randomised Controlled Cross-Over Study. J Frailty Aging 2014; 3:132-8. [PMID: 27049907 DOI: 10.14283/jfa.2014.14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Whilst resistance training has been proven to convey considerable benefits to older people; immediately post-exercise there may be elevated transient risks for cardiac events and falls. Objectives and Measurements: We assessed the acute effects of eccentrically-biased (EB) and conventional (CONV) resistance exercise on: platelet number, activation and granule exocytsosis; and mean velocity of centre of pressure displacement (Vm). DESIGN, SETTING, PARTICIPANTS AND INTERVENTION Ten older adults (7 males, 3 females; 69 ± 4 years) participated in this randomised controlled cross-over study in which they performed EB and CONV training sessions that were matched for total work and a control condition. RESULTS Immediately post-exercise there was a statistically significant difference in platelet count between the control condition, in which it had declined (pre 224 ± 35 109/L; post 211 ± 30 109/L: P < 0.05) and CONV in which it had increased (pre 236 ± 55 109/L; post 242 ± 51 109/L: P > 0.05). There was no change in platelet activation and granule exocytsosis or Vm following EB and CONV. CONCLUSIONS Overall, while minor differences between regimens were observed, no major adverse effect on parameters of platelet function or centre of pressure displacement were observed acutely following either regimen. Eccentrically-biased and conventional resistance exercise training regimens do not appear to present an elevated acute risk in the context of changes to platelet function contributing to a cardiac event or postural stability increasing falls risk for apparently healthy older adults.
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Affiliation(s)
- I Selva Raj
- Professor Stephen Bird, Royal Melbourne Institute of Technology University, Health Innovations Research Institute and School of Medical Sciences, Bundoora West Campus, PO Box 71, Bundoora, Victoria 3083, Australia, Phone: +(61 3) 9925 7257, E-mail:
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Affiliation(s)
- Matthew D. Linden
- The Centre for Microscopy; Characterisation and Analysis; The University of Western Australia; Nedlands WA 6009 Australia
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Abstract
PURPOSE Hyperactive platelets contribute to the thrombotic response in humans, and exercise transiently increases platelet function. Caffeine is routinely used by athletes as an ergogenic aid, but the combined effect of exercise and caffeine on platelet function has not been investigated. METHODS Twelve healthy males were randomly assigned to one of four groups and undertook four experimental trials of a high-intensity aerobic interval training (AIT) bout or rest with ingestion of caffeine (3 mg·kg(-1)) or placebo. AIT was 8 × 5 min at approximately 75% peak power output (approximately 80% V˙O2peak) and 1-min recovery (approximately 40% peak power output, approximately 50% V˙O2peak) intervals. Blood/urine was collected before, 60, and 90 min after capsule ingestion and analyzed for platelet aggregation/activation. RESULTS AIT increased platelet reactivity to adenosine diphosphate (placebo 30.3%, caffeine 13.4%, P < 0.05) and collagen (placebo 10.8%, caffeine 5.1%, P < 0.05) compared with rest. Exercise placebo increased adenosine diphosphate-induced aggregation 90 min postingestion compared with baseline (40.5%, P < 0.05), but the increase when exercise was combined with caffeine was small (6.6%). During the resting caffeine protocol, collagen-induced aggregation was reduced (-4.3%, P < 0.05). AIT increased expression of platelet activation marker PAC-1 with exercise placebo (P < 0.05) but not when combined with caffeine. CONCLUSION A single bout of AIT increases platelet function, but caffeine ingestion (3 mg·kg(-1)) does not exacerbate platelet function at rest or in response to AIT. Our results provide new information showing caffeine at a dose that can elicit ergogenic effects on performance has no detrimental effect on platelet function and may have the potential to attenuate increases in platelet activation and aggregation when undertaking strenuous exercise.
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Affiliation(s)
- Joshua P Whittaker
- Health Innovations Research Institute, School of Medical Sciences, RMIT University, Melbourne, Australia
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Yip C, Ignjatovic V, Attard C, Monagle P, Linden MD. First report of elevated monocyte-platelet aggregates in healthy children. PLoS One 2013; 8:e67416. [PMID: 23826296 PMCID: PMC3691142 DOI: 10.1371/journal.pone.0067416] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 05/20/2013] [Indexed: 11/25/2022] Open
Abstract
Platelets are subcellular fragments which circulate in blood and have well established roles in thrombosis and haemostasis in adults. Upon activation, platelets undergo granule exocytosis and express P-Selectin on the cell membrane which binds a ligand on monocytes, leading to monocyte-platelet aggregation. Elevated circulating monocyte-platelet aggregates in adults are linked to atherothrombosis, but have not been investigated in children where thrombosis is less common. This study aimed to measure monocyte-platelet aggregate formation in children using whole blood flow cytometry. Monocyte-platelet aggregates as well as activation and granule exocytosis of platelets were measured in healthy adults (n = 15, median age 28 years) and healthy children (n = 28, median age 7 years). Monocyte-platelet aggregates in healthy children were elevated compared to healthy adults (37.8±4.4% vs 15.5±1.9% respectively, p<0.01). However, this was not accompanied by any difference in platelet activation (PAC-1 binding 6.8±1.5% vs 6.3±2.0% respectively, p = ns) or granule exocytosis (P-selectin expression 4.4±0.5% vs 3.1±0.5% respectively, p = ns). Despite comparable numbers of platelets bound per monocyte (GPIb MFI 117.3±13.7 vs 130.9±28.6 respectively, p = ns), surface P-selectin expression per platelet-bound monocyte was lower in children compared to adults. We therefore provide the first data of elevated monocyte-platelet aggregates in healthy children.
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Affiliation(s)
- Christina Yip
- School of Medical Sciences, Royal Melbourne Institute of Technology University, Melbourne, Australia
- Murdoch Childrens Research Institute, Melbourne, Australia
| | - Vera Ignjatovic
- Murdoch Childrens Research Institute, Melbourne, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, Australia
| | - Chantal Attard
- Murdoch Childrens Research Institute, Melbourne, Australia
| | - Paul Monagle
- Murdoch Childrens Research Institute, Melbourne, Australia
- Department of Paediatrics, The University of Melbourne, Melbourne, Australia
- Department of Clinical Haematology, Royal Children’s Hospital, Melbourne, Australia
| | - Matthew D. Linden
- Centre for Microscopy Characterisation and Analysis, The University of Western Australia, Perth, Australia
- * E-mail:
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Abstract
Platelets are cell fragments which circulate in blood. They are of pivotal importance in blood clot formation, affecting thrombosis and haemostasis. By rapidly altering the activation and expression of surface receptors, platelets are able to quickly undergo structural and phenotypic changes in response to stimulation, such as collagen exposure on injured vascular endothelium. This response to stimulation allows platelets to become adhesive, aggregate to form a thrombus, and release a variety of mediators affecting coagulation, inflammation, and chemotaxis at the site of injury. Therefore, in addition to their critical role in thrombosis and haemostasis, platelets also play a role in immunity, inflammation, wound healing, haematologic malignancies, and metabolic disorders. The role of platelets in disease, particularly in atherothrombosis, is increasingly the focus of current research and antiplatelet therapy plays a significant role in the prevention and treatment of atherothrombotic and inflammatory diseases.
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Affiliation(s)
- Matthew D Linden
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, WA, Australia
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Abstract
Flow cytometry is a powerful and versatile tool which can be used to provide substantial phenotypic data on platelets by yielding quantitative information of their physical and antigenic properties. This includes surface expression of functional receptors, bound ligands, expression of granule components, interaction of platelets with other platelets via aggregation, or interaction with other blood components, such as leukocytes or the plasma coagulation system. Quantitative assessment of these parameters may facilitate the diagnosis of inherited or acquired platelet disorders, assist in the diagnosis of diseases associated with platelet activation, or assist in the monitoring of safety and efficacy of antiplatelet therapy.
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Affiliation(s)
- Matthew D Linden
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, WA, Australia
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31
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Mosawy S, Jackson DE, Woodman OL, Linden MD. Inhibition of platelet-mediated arterial thrombosis and platelet granule exocytosis by 3',4'-dihydroxyflavonol and quercetin. Platelets 2012; 24:594-604. [PMID: 23249183 DOI: 10.3109/09537104.2012.749396] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Flavonols are polyphenolic compounds with broad-spectrum kinase inhibitory, as well as potent anti-oxidant and anti-inflammatory properties. Anti-platelet potential of quercetin (Que) and several related flavonoids have been reported; however, few studies have assessed the ability of flavonols to inhibit exocytosis of different platelet granules or to inhibit thrombus formation in vivo. 3',4'-Dihydroxyflavonol (DiOHF) is a flavonol which is structurally related to Que and has been shown to have greater anti-oxidant capacity and to improve the endothelial function in the context of diabetes and ischaemia/reperfusion injury. While the structural similarity to Que suggests DiOHF may have a potential to inhibit platelet function, no studies have assessed the anti-platelet potential of DiOHF. We therefore investigated platelet granule inhibition and potential to delay arterial thrombosis by Que and DiOHF. Both Que and DiOHF showed inhibition of collagen, adenosine diphosphate and arachidonic acid stimulated platelet aggregation, agonist-induced GPIIb/IIIa activation as demonstrated by PAC-1 and fibrinogen binding. While both flavonols inhibited agonist-induced granule exocytosis, greater inhibition of dense granule exocytosis occurred with DiOHF as measured by both ATP release and flow cytometry. In contrast, while Que inhibited agonist-induced P-selectin expression, as measured by both platelet surface P-selectin expression and upregulation of surface GPIIIa expression, inhibition by DiOHF was not significant for either parameter. C57BL/6 mice treated with 6 mg kg(-1) IV Que or DiOHF maintained greater blood flow following FeCl3-induced carotid artery injury when compared to the vehicle control. We provide evidence that Que and DiOHF improve blood flow following arterial injury in part by attenuating platelet granule exocytosis.
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Affiliation(s)
- Sapha Mosawy
- Health Innovations Research Institute, RMIT University , Melbourne , Australia
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32
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Linden MD. Toward a guided approach to platelet activation in diabetes. J Thromb Thrombolysis 2012; 35:175-7. [PMID: 23212805 DOI: 10.1007/s11239-012-0852-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
The term resistance has been applied to interindividual variability in platelet reactivity during antiplatelet therapy or to thrombosis despite appropriate therapy. In particular "aspirin resistance" and "clopidogrel resistance" have been the subject of intense investigation for their association with poor cardiovascular outcomes. Several mechanisms have been investigated including resistance arising from poor bioavailability, especially in clopidogrel therapy as resulting from a loss of function variant in hepatic metabolism required for prodrug activation. A limitation of studies linking on-treatment reactivity and clinical outcome is that they have been performed in high-risk patients with recent atherothrombotic disease. On-treatment platelet reactivity correlates with acuity of recent atherothrombosis, and variability in pretreatment platelet function predicts on-treatment platelet function for both aspirin and clopidogrel. It is therefore likely that high on-treatment platelet function at the time of testing may often result from underlying platelet hyperreactivity related to acute atherothrombosis, rather than true pharmacological resistance. The association of high on-treatment platelet reactivity with poor clinical outcomes may therefore be attributed to variability in underlying burden of disease instead of, or in addition to, pharmacological resistance to antiplatelet therapy.
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Affiliation(s)
- Matthew D Linden
- School of Medical Sciences and Health Innovations Research Institute, RMIT University, Melbourne, Australia.
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Psaila B, Bussel JB, Frelinger AL, Babula B, Linden MD, Li Y, Barnard MR, Tate C, Feldman EJ, Michelson AD. Differences in platelet function in patients with acute myeloid leukemia and myelodysplasia compared to equally thrombocytopenic patients with immune thrombocytopenia. J Thromb Haemost 2011; 9:2302-10. [PMID: 21920014 PMCID: PMC3210015 DOI: 10.1111/j.1538-7836.2011.04506.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Severe thrombocytopenia is a major risk factor for hemorrhage, but platelet function and bleeding risk at low platelet counts are poorly understood, because of the limitations of platelet function testing at very low platelet counts. OBJECTIVES To examine and compare platelet function in severely thrombocytopenic patients with acute myeloid leukemia (AML) or myelodysplasia (MDS) with that in patients with immune thrombocytopenia (ITP). METHODS Whole blood flow cytometric measurement of platelet activation and platelet reactivity to agonists was correlated with the immature platelet fraction (IPF) and bleeding symptoms. RESULTS Patients with AML/MDS had smaller platelets, lower IPF and substantially lower platelet surface expression of activated glycoprotein (GP)IIb-IIIa and GPIb, both with and without addition of ex vivo ADP or thrombin receptor-activating peptide, than patients with ITP. In both ITP and AML/MDS patients, increased platelet surface GPIb on circulating platelets and expression of activated GPIIb-IIIa and GPIb on ex vivo activated platelets correlated with a higher IPF. Whereas platelet reactivity was higher for AML/MDS patients with bleeding than for those with no bleeding, platelet reactivity was lower for ITP patients with bleeding than for those with no bleeding. CONCLUSIONS AML/MDS patients have lower in vivo platelet activation and ex vivo platelet reactivity than patients with ITP. The proportion of newly produced platelets correlates with the expression of platelet surface markers of activation. These differences might contribute to differences in bleeding tendency between AML/MDS and ITP patients. This study is the first to define differences in platelet function between AML/MDS patients and ITP patients with equivalent degrees of thrombocytopenia.
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Affiliation(s)
- Bethan Psaila
- Platelet Disorders Center, Division of Pediatric Hematology-Oncology, Weill-Cornell Medical College, New York, NY, U.S.A
- Department of Haematology, Imperial College School of Medicine, London, U.K
| | - James B. Bussel
- Platelet Disorders Center, Division of Pediatric Hematology-Oncology, Weill-Cornell Medical College, New York, NY, U.S.A
| | - Andrew L. Frelinger
- Center for Platelet Function Studies, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, U.S.A
- Center for Platelet Research Studies, Division of Hematology/Oncology, Children’s Hospital Boston, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, U.S.A
| | - Bracken Babula
- Platelet Disorders Center, Division of Pediatric Hematology-Oncology, Weill-Cornell Medical College, New York, NY, U.S.A
| | - Matthew D. Linden
- Center for Platelet Function Studies, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, U.S.A
| | - Youfu Li
- Center for Platelet Function Studies, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, U.S.A
| | - Marc R. Barnard
- Center for Platelet Function Studies, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, U.S.A
- Center for Platelet Research Studies, Division of Hematology/Oncology, Children’s Hospital Boston, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, U.S.A
| | - Chinara Tate
- Platelet Disorders Center, Division of Pediatric Hematology-Oncology, Weill-Cornell Medical College, New York, NY, U.S.A
| | - Eric J. Feldman
- Division of Hematology and Medical Oncology, Weill-Cornell Medical College, New York, NY, U.S.A
| | - Alan D. Michelson
- Center for Platelet Function Studies, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, U.S.A
- Center for Platelet Research Studies, Division of Hematology/Oncology, Children’s Hospital Boston, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, U.S.A
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Burchall G, Linden MD, Teede H, Piva TJ. Hemostatic Abnormalities and Relationships to Metabolic and Hormonal Status in Polycystic Ovarian Syndrome. Trends Cardiovasc Med 2011; 21:6-14. [DOI: 10.1016/j.tcm.2012.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Linden MD, Jackson DE. Platelets: pleiotropic roles in atherogenesis and atherothrombosis. Int J Biochem Cell Biol 2010; 42:1762-6. [PMID: 20673808 DOI: 10.1016/j.biocel.2010.07.012] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 07/06/2010] [Accepted: 07/21/2010] [Indexed: 01/07/2023]
Abstract
Platelets are small, anucleate blood elements of critical importance in cardiovascular disease. The ability of platelets to activate and aggregate to form blood clots in response to endothelial injury, such as plaque rupture, is well established. These cells are therefore important contributors to ischaemia in atherothrombosis, and antiplatelet therapy is effective for this reason. However, growing evidence suggests that platelets are also important mediators of inflammation and play a central role in atherogenesis itself. Interactions between activated platelets, leukocytes and endothelial cells trigger autocrine and paracrine activation signals, resulting in leukocyte recruitment at and into the vascular wall. Direct physical interaction may contribute also, through platelet adhesion molecules assisting localization of monocytes to the site of atherogenesis and platelet granule release contributing to the chronic inflammatory milieu which leads to foam cell development and accelerated atherogenesis. Recent studies have shown that antiplatelet therapy in animal models of accelerated atherogenesis can lead to decreased plaque size and improve plaque stability. This review examines the complexity of platelet function and the nature of interactions between activated platelets, leukocytes and endothelial cells. We focus on the growing body of evidence that platelets play a critical role in atherogenesis and contribute to progression of atherosclerosis.
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Affiliation(s)
- Matthew D Linden
- School of Medical Sciences, RMIT University, Bundoora, VIC, Australia.
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Przyklenk K, Frelinger AL, Linden MD, Whittaker P, Li Y, Barnard MR, Adams J, Morgan M, Al-Shamma H, Michelson AD. Targeted inhibition of the serotonin 5HT2A receptor improves coronary patency in an in vivo model of recurrent thrombosis. J Thromb Haemost 2010; 8:331-40. [PMID: 19922435 PMCID: PMC2916638 DOI: 10.1111/j.1538-7836.2009.03693.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Release of serotonin and activation of serotonin 5HT2A receptors on platelet surfaces is a potent augmentative stimulus for platelet aggregation. However, earlier-generation serotonin receptor antagonists were not successfully exploited as antiplatelet agents, possibly owing to their lack of specificity for the 5HT2A receptor subtype. OBJECTIVE To assess whether targeted inhibition of the serotonin 5HT2A receptor attenuates recurrent thrombosis and improves coronary patency in an in vivo canine model mimicking unstable angina. METHODS In protocol 1, anesthetized dogs were pretreated with a novel, selective inverse agonist of the 5HT2A receptor (APD791) or saline. Recurrent coronary thrombosis was then initiated by coronary artery injury+stenosis, and coronary patency was monitored for 3 h. Protocol 2 was similar, except that: (i) treatment with APD791 or saline was begun 1 h after the onset of recurrent thrombosis; (ii) template bleeding time was measured; and (iii) blood samples were obtained for in vitro flow cytometric assessment of platelet responsiveness to serotonin. RESULTS APD791 attenuated recurrent thrombosis, irrespective of the time of treatment: in both protocols, flow-time area (index of coronary patency; normalized to baseline coronary flow) averaged 58-59% (P<0.01) following administration of APD791 vs. 21-28% in saline controls. Moreover, the in vivo antithrombotic effect of APD791 was not accompanied by increased bleeding, but was associated with significant and selective inhibition of serotonin-mediated platelet activation. CONCLUSION 5HT2A receptor inhibition with APD791, even when initiated after the onset of recurrent thrombosis, improves coronary patency in the in vivo canine model.
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Affiliation(s)
- K Przyklenk
- Center for Platelet Function Studies, Department of Emergency Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
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Frelinger AL, Li Y, Linden MD, Barnard MR, Fox ML, Christie DJ, Furman MI, Michelson AD. Association of cyclooxygenase-1-dependent and -independent platelet function assays with adverse clinical outcomes in aspirin-treated patients presenting for cardiac catheterization. Circulation 2009; 120:2586-96. [PMID: 19996015 DOI: 10.1161/circulationaha.109.900589] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Poor clinical outcome in aspirin-treated patients has been termed aspirin resistance and may result from inadequate inhibition of platelet cyclooxygenase-1 (COX-1) by aspirin. The objectives of this study were to determine prospectively whether COX-1-dependent and other platelet function assays correlate with clinical outcomes in aspirin-treated patients. METHODS AND RESULTS Blood was collected before percutaneous coronary intervention from 700 consecutive aspirin-treated (81 or 325 mg for > or =3 days) patients. Platelet function was tested by (1) serum thromboxane B(2); (2) arachidonic acid-stimulated platelet surface P-selectin and activated glycoprotein IIb/IIIa and leukocyte-platelet aggregates; and (3) platelet function analyzer (PFA)-100 collagen-epinephrine and collagen-ADP closure time (CT). Adverse clinical outcomes of all-cause death, cardiovascular death, and major adverse cardiovascular events (cardiovascular death, myocardial infarction, hospitalization for revascularization, or acute coronary syndrome) were assessed by telephone interview and/or medical record review. Clinical outcomes information was obtained at 24.8+/-0.3 months after platelet function testing. By univariate analysis, COX-1-dependent assays, including serum thromboxane B(2) level, were not associated with adverse clinical outcomes, whereas the COX-1-independent assay, PFA-100 collagen-ADP CT <65 seconds, was associated with major adverse cardiovascular events (P=0.0149). After adjustment for covariables (including sex, aspirin dose, Thrombolysis in Myocardial Infarction risk score, clopidogrel use), both serum thromboxane B(2) >3.1 ng/mL and PFA-100 collagen-ADP CT <65 seconds were associated with major adverse cardiovascular events. In contrast, indirect measures of platelet COX-1 (arachidonic acid-stimulated platelet markers, shortened PFA-100 collagen-epinephrine CT) were not significantly associated with adverse clinical outcomes even after adjustment for covariables. CONCLUSIONS In this prospective study of 700 aspirin-treated patients presenting for angiographic evaluation of coronary artery disease, residual platelet COX-1 function measured by serum thromboxane B(2) and COX-1-independent platelet function measured by PFA-100 collagen-ADP CT, but not indirect COX-1-dependent assays (arachidonic acid-stimulated platelet markers, shortened PFA-100 collagen-epinephrine CT), correlate with subsequent major adverse cardiovascular events. This study suggests that multiple mechanisms, including but not confined to inadequate inhibition of COX-1, are responsible for poor clinical outcomes in aspirin-treated patients, and therefore the term aspirin resistance is inappropriate.
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Affiliation(s)
- Andrew L Frelinger
- Division of Hematology/Oncology, Children's Hospital Boston, 300 Longwood Ave., Boston, MA 02115-5737, USA.
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Frelinger AL, Li Y, Linden MD, Tarnow I, Barnard MR, Fox ML, Michelson AD. Aspirin 'resistance': role of pre-existent platelet reactivity and correlation between tests. J Thromb Haemost 2008; 6:2035-44. [PMID: 18983514 DOI: 10.1111/j.1538-7836.2008.03184.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
BACKGROUND Aspirin 'resistance' is a widely used term for hyporesponsiveness to aspirin in a platelet function test. Serum thromboxane (TX) B(2) is the most specific test of aspirin's effect on platelets. OBJECTIVES (i) To examine the role of pre-existent platelet hyperreactivity in aspirin 'resistance'. (ii) To determine the correlation between aspirin resistance defined by serum TXB(2) and other assays of platelet function. METHODS To enable pre-aspirin samples to be drawn, platelet function was measured in normal subjects (n = 165) before and after aspirin 81 mg daily for seven days. RESULTS The proportion of the post-aspirin platelet function predicted by the pre-aspirin platelet function was 28.3 +/- 7.5% (mean +/- asymptotic standard error) for serum TXB(2), 39.3 +/- 6.8% for urinary 11-dehydro TXB(2), 4.4 +/- 7.7% for arachidonic acid-induced platelet aggregation, 40.4 +/- 7.1% for adenosine diphosphate-induced platelet aggregation, 26.3 +/- 9.2% for the VerifyNow Aspirin Assay, and 45.0 +/- 10.9% for the TEG PlateletMapping System with arachidonic acid. There was poor agreement between aspirin-resistant subjects identified by serum TXB(2) vs. aspirin-resistant subjects identified by the other five assays, irrespective of whether the analysis was based on categorical or continuous variables. Platelet count correlated with pre-aspirin serum TXB(2) and VerifyNow Aspirin Assay, but not with any post-aspirin platelet function test. CONCLUSIONS (i) Aspirin 'resistance' (i.e. hyporesponsiveness to aspirin in a laboratory test) is in part unrelated to aspirin but is the result of underlying platelet hyperreactivity prior to the institution of aspirin therapy. (ii) Aspirin resistance defined by serum TXB(2) shows a poor correlation with aspirin resistance defined by other commonly used assays.
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Affiliation(s)
- A L Frelinger
- Department of Pediatrics, Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Frelinger AL, Jakubowski JA, Li Y, Barnard MR, Linden MD, Tarnow I, Fox ML, Sugidachi A, Winters KJ, Furman MI, Michelson AD. The active metabolite of prasugrel inhibits adenosine diphosphate- and collagen-stimulated platelet procoagulant activities. J Thromb Haemost 2008; 6:359-65. [PMID: 18021304 DOI: 10.1111/j.1538-7836.2008.02838.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
BACKGROUND Prasugrel is a novel antiplatelet prodrug of the same thienopyridine class as clopidogrel and ticlopidine. Metabolism of prasugrel generates the active metabolite R-138727, an antagonist of the platelet P2Y(12) adenosine diphosphate (ADP) receptor, leading to inhibition of ADP-mediated platelet activation and aggregation. ADP also enhances the platelet response to collagen, and these two agonists contribute to the generation of platelet procoagulant activity. We therefore examined whether R-138727 inhibits ADP- and collagen-triggered platelet procoagulant activities. METHODS AND RESULTS As shown by whole blood flow cytometry, R-138727 inhibited surface phosphatidylserine expression on ADP plus collagen-stimulated platelets and tissue factor (TF) expression on ADP-, collagen-, and ADP plus collagen-stimulated monocyte-platelet aggregates. R-138727 reduced monocyte-platelet aggregate formation, thereby further inhibiting TF expression. ADP, collagen, and ADP plus collagen accelerated the kinetics of thrombin generation in recalcified whole blood and R-138727 significantly inhibited this acceleration. Clot strength in a modified thromboelastograph system was also inhibited by R-138727 (IC50 0.7 +/- 0.1 microM). CONCLUSIONS In addition to its previously known inhibitory effects on platelet activation and aggregation, the active metabolite of prasugrel, R-138727, inhibits platelet procoagulant activity in whole blood (as determined by phosphatidylserine expression on platelets and TF expression on monocyte-platelet aggregates), resulting in the functional consequences of delayed thrombin generation and impaired clot development.
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Affiliation(s)
- A L Frelinger
- Center for Platelet Function Studies, and Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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Frelinger AL, Jakubowski JA, Li Y, Barnard MR, Linden MD, Tarnow I, Fox ML, Sugidachi A, Winters KJ, Furman MI, Michelson AD. The active metabolite of prasugrel inhibits adenosine diphosphate- and collagen-stimulated platelet procoagulant activities. J Thromb Haemost 2007; 6:359-65. [PMID: 18021304 DOI: 10.1111/j.1538-7836.2007.02838.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Prasugrel is a novel antiplatelet prodrug of the same thienopyridine class as clopidogrel and ticlopidine. Metabolism of prasugrel generates the active metabolite R-138727, an antagonist of the platelet P2Y(12) adenosine diphosphate (ADP) receptor, leading to inhibition of ADP-mediated platelet activation and aggregation. ADP also enhances the platelet response to collagen, and these two agonists contribute to the generation of platelet procoagulant activity. We therefore examined whether R-138727 inhibits ADP- and collagen-triggered platelet procoagulant activities. METHODS AND RESULTS As shown by whole blood flow cytometry, R-138727 inhibited surface phosphatidylserine expression on ADP plus collagen-stimulated platelets and tissue factor (TF) expression on ADP-, collagen-, and ADP plus collagen-stimulated monocyte-platelet aggregates. R-138727 reduced monocyte-platelet aggregate formation, thereby further inhibiting TF expression. ADP, collagen, and ADP plus collagen accelerated the kinetics of thrombin generation in recalcified whole blood and R-138727 significantly inhibited this acceleration. Clot strength in a modified thromboelastograph system was also inhibited by R-138727 (IC50 0.7 +/- 0.1 microM). CONCLUSIONS In addition to its previously known inhibitory effects on platelet activation and aggregation, the active metabolite of prasugrel, R-138727, inhibits platelet procoagulant activity in whole blood (as determined by phosphatidylserine expression on platelets and TF expression on monocyte-platelet aggregates), resulting in the functional consequences of delayed thrombin generation and impaired clot development.
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Affiliation(s)
- A L Frelinger
- Center for Platelet Function Studies, and Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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Linden MD, Barnard MR, Frelinger A, Michelson AD, Przyklenk K. Effect of adenosine A2 receptor stimulation on platelet activation-aggregation: differences between canine and human models. Thromb Res 2007; 121:689-98. [PMID: 17727923 PMCID: PMC2346597 DOI: 10.1016/j.thromres.2007.07.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 06/11/2007] [Accepted: 07/01/2007] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Adenosine A(2) agonists improve arterial patency in experimental models of recurrent thrombosis, an effect purportedly triggered by stimulation of platelet A(2) receptors and subsequent down-regulation of platelet function. However: (i) there is no direct evidence to substantiate this premise; and (ii) given the recognized differences among species in platelet signaling, it is possible that the mechanisms of A(2) receptor stimulation may be model-dependent. Accordingly, we applied an integrated in vivo and in vitro approach, using both canine and human models, to test the hypothesis that the anti-thrombotic effects of A(2) agonist treatment are due in part to inhibition of platelet activation. METHODS In Protocol 1, recurrent coronary thrombosis was triggered in anesthetized dogs by application of a stenosis at a site of arterial injury. Coronary patency and flow cytometric indices of platelet activation (P-selectin expression; formation of heterotypic aggregates) were compared in dogs pre-treated with the A(2) agonist CGS 21680 versus controls. In Protocols 2 and 3, blood samples were obtained from dogs and human volunteers. In vitro aggregation and platelet activation (assessed by impedance aggregometry and flow cytometry, respectively) were quantified in paired aliquots pre-incubated with CGS versus vehicle. RESULTS In the canine models, CGS improved in vivo coronary patency and attenuated in vitro aggregation but, contrary to our hypothesis, did not evoke a down-regulation in platelet activation. In contrast, in human blood samples, CGS attenuated both in vitro aggregation and flow cytometric markers of platelet activation-aggregation. CONCLUSION The mechanisms contributing to the anti-thrombotic effect of A(2) agonist treatment are species-dependent: adenosine A(2) receptor stimulation inhibits platelet activation in human, but not canine, models.
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Affiliation(s)
- Matthew D. Linden
- Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester MA
- Department of Pediatrics, University of Massachusetts Medical School, Worcester MA
| | - Marc R. Barnard
- Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester MA
| | - A.L. Frelinger
- Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester MA
- Department of Pediatrics, University of Massachusetts Medical School, Worcester MA
| | - Alan D. Michelson
- Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester MA
- Department of Pediatrics, University of Massachusetts Medical School, Worcester MA
| | - Karin Przyklenk
- Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester MA
- Department of Emergency Medicine, University of Massachusetts Medical School, Worcester MA
- Department of Anesthesiology, University of Massachusetts Medical School, Worcester MA
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Frelinger AL, Jakubowski JA, Li Y, Barnard MR, Fox ML, Linden MD, Sugidachi A, Winters KJ, Furman MI, Michelson AD. The active metabolite of prasugrel inhibits ADP-stimulated thrombo-inflammatory markers of platelet activation: Influence of other blood cells, calcium, and aspirin. Thromb Haemost 2007; 98:192-200. [PMID: 17598013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The novel thienopyridine prodrug prasugrel, a platelet P2Y(12) ADP receptor antagonist, requires in vivo metabolism for activity. Although pharmacological data have been collected on the effects of prasugrel on platelet aggregation, there are few data on the direct effects of the prasugrel's active metabolite, R-138727, on other aspects of platelet function. Here we examined the effects of R-138727 on thrombo-inflammatory markers of platelet activation, and the possible modulatory effects of other blood cells, calcium, and aspirin. Blood (PPACK or citrate anticoagulated) from healthy donors pre- and post-aspirin was incubated with R-138727 and the response to ADP assessed in whole blood or platelet-rich plasma (PRP) by aggregometry and flow cytometric analysis of leukocyte-platelet aggregates, platelet surface P-selectin, and GPIIb-IIIa activation. Low-micromolar concentrations of R-138727 resulted in a rapid and consistent inhibition of these ADP-stimulated thrombo-inflammatory markers. These rapid kinetics required physiological calcium levels, but were largely unaffected by aspirin. Lower IC(50) values in whole blood relative to PRP suggested that other blood cells affect ADP-induced platelet activation and hence the net inhibition by R-138727. R-138727 did not inhibit P2Y(12)-mediated ADP-induced shape change, even at concentrations that completely inhibited platelet aggregation, confirming the specificity of R-138727 for P2Y(12). In conclusion, R-138727, the active metabolite of prasugrel, results in rapid, potent, consistent, and selective inhibition of P2Y(12)-mediated up-regulation of thrombo-inflammatory markers of platelet activation. This inhibition is enhanced in the presence other blood cells and calcium, but not aspirin.
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Affiliation(s)
- Andrew L Frelinger
- Center for Platelet Function Studies, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
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Linden MD, Furman MI, Frelinger AL, Fox ML, Barnard MR, Li Y, Przyklenk K, Michelson AD. Indices of platelet activation and the stability of coronary artery disease. J Thromb Haemost 2007; 5:761-5. [PMID: 17371489 DOI: 10.1111/j.1538-7836.2007.02462.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
AIM To determine whether indices of platelet activation are associated with the stability of coronary artery disease (CAD). METHODS Platelet function was examined in 677 consecutive aspirin-treated patients presenting for cardiac catheterization. Patients were grouped into recent myocardial infarction (MI), no MI but angiographically documented CAD (non-MI CAD) and no angiographically detectible CAD (no CAD), as well as additional subgroups. RESULTS Compared with non-MI CAD or no CAD patients, more patients with recent MI had a shortened platelet function analyzer (PFA)-100 collagen-epinephrine closure time (CT) and increased circulating monocyte-platelet aggregates, neutrophil-platelet aggregates, activated platelet surface GPIIb-IIIa and plasma soluble CD40 ligand (sCD40L). More patients with non-MI CAD had shortened PFA-100 CTs and increased monocyte-platelet aggregates compared with patients with no CAD. Platelet surface P-selectin did not differ among the groups. Subgroup analysis revealed that decreasing PFA-100 CT correlated with the stability of CAD. CONCLUSIONS Indices of platelet activation, especially the PFA-100 CT, are associated with the stability of CAD, and may reflect plaque instability, an ongoing thrombotic state and/or reduced responsiveness to aspirin.
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Affiliation(s)
- M D Linden
- Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Afshar-Kharghan V, Agah R, Andrews RK, Aster RH, Atkinson B, Awtry EH, Bahou WF, Barnard MR, Bavry AA, Bayer AS, Becker RC, Bergmeier W, Berndt MC, Bhatt DL, Bizzaro N, Blajchman MA, Bouchard BA, Brass LF, Bray PF, Briggs C, Brill A, Bussel JB, Butenas S, Cattaneo M, Chong BH, Clemetson KJ, Clemetson JM, Coller BS, Crawford LE, de Groot PG, del Zoppo GJ, Dubois C, Eisert WG, FitzGerald GA, Francis JL, Freedman JE, Freedman J, Frelinger III A, Fries S, Furie BC, Furie B, Furman MI, García-Alonso Á, Goldschmidt PJ, Grosser T, Gurguis GN, Harrison P, Hartwig JH, Ike da YU, Israels SJ, Italiano JE, Jennings LK, Kaplan C, Karpatkin S, Keeling DM, Kimura Y, Kurkjian CD, Kuter DJ, Lambert MP, Lee DH, Levin J, Li QX, Li Z, Lind SE, Linden MD, Lopes NH, López JA, Loscalzo J, Ma YQ, Machin SJ, Mann KG, Mannucci PM, Maron BA, Masters CL, McCrae KR, McEver RP, Menart B, Michelson AD, Moake J, Murray N, Nardi MA, Newman DK, Newman PJ, Nierodzik ML, Nieuwland R, Novinska M, Nurden AT, Nurden P, Perrotta PL, Pesho MM, Plow EF, Poncz M, Poon MC, Prévost N, Rao AK, Rathore V, Reed GL, Rex S, Rinder CS, Rinder HM, Roberts I, Ruggeri ZM, Savage B, Savion N, Senis Y, Shattil SJ, Sixma JJ, Smith BR, Snyder EL, Sobel M, Stalker TJ, Steinhubl SR, Stratmann B, Sturk A, Sudo T, Tef feri AL, Tomlinson MG, Topol EJ, Tracy PB, Tschoepe D, Varon D, Vijayan KV, Wagner DD, Watson SP, White, II GC, White JG, McCabe White M, Wilcox DA, Woulfe DS, Yeaman MR, Zhu L. Contributors. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50760-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Tarnow I, Michelson AD, Frelinger AL, Linden MD, Li Y, Fox ML, Barnard MR, O'Sullivan BP. Cystic fibrosis heterozygotes do not have increased platelet activation. Thromb Res 2007; 121:159-62. [PMID: 17532368 DOI: 10.1016/j.thromres.2007.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 04/10/2007] [Accepted: 04/16/2007] [Indexed: 11/18/2022]
Abstract
INTRODUCTION We have previously demonstrated platelet hyperreactivity in cystic fibrosis (CF) patients. Carriers of one CF mutation (heterozygotes) have been shown to have abnormalities related to the presence of only one-half the normal amount of CF transmembrane conductance regulator protein. Platelet hyperreactivity in CF heterozygotes would be an important cardiovascular risk factor, since approximately 1 in 25 Caucasians is a CF carrier. MATERIALS AND METHODS We used highly sensitive assays of platelet activation to assess the difference between 16 CF heterozygotes and 16 age- and sex-matched healthy controls without CF mutations. RESULTS We found no difference in platelet activation between CF heterozygotes and controls. CONCLUSIONS The 50% reduction in the CF transmembrane conductance regulator protein in heterozygotes is insufficient to cause platelet activation.
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Affiliation(s)
- Inge Tarnow
- Department of Physiology and Biochemistry, University of Copenhagen, The Faculty of Life Sciences, Frederiksberg C, Denmark
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Michelson AD, Linden MD, Furman MI, Li Y, Barnard MR, Fox ML, Lau WC, McLaughlin TJ, Frelinger AL. Evidence that pre-existent variability in platelet response to ADP accounts for 'clopidogrel resistance'. J Thromb Haemost 2007; 5:75-81. [PMID: 17002661 DOI: 10.1111/j.1538-7836.2006.02234.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Clopidogrel is a widely used antithrombotic agent that inhibits the platelet P2Y(12) adenosine diphosphate (ADP) receptor. There is increasing interest in 'clopidogrel resistance'. OBJECTIVES To determine whether 'clopidogrel resistance' is accounted for by a pre-existent variability in platelet response to ADP. METHODS Platelet response to 20 microm ADP was analyzed by four independent whole blood flow cytometric assays: platelet surface activated GPIIb-IIIa, platelet surface P-selectin, monocyte-platelet aggregates and neutrophil-platelet aggregates. In 25 consecutive, non-aspirin-treated healthy subjects, we studied platelet response before and after clopidogrel administration. In addition, we studied the platelet response in 613 consecutive aspirinated patients with or without coronary artery disease (CAD, as determined by angiography) who had or had not been treated with clopidogrel. In these patients, we tested for homogeneity of variance across all durations of clopidogrel exposure and severity of CAD by estimating the 'goodness of fit' of two independent models. RESULTS In the healthy subjects, pre-clopidogrel response to ADP predicted post-clopidogrel response to ADP. In the patients, clopidogrel, as expected, inhibited the platelet response to ADP. However, irrespective of the duration of clopidogrel administration, the severity of CAD, and the dose of aspirin, clopidogrel did not increase the variance in the platelet response to ADP in any of the four assays of platelet response. CONCLUSIONS These studies provide evidence that 'clopidogrel resistance' is accounted for by a pre-existent variability in platelet response to ADP and this variability is not increased by clopidogrel administration.
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Affiliation(s)
- A D Michelson
- Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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Michelson AD, Linden MD, Barnard MR, Furman MI, Frelinger A. Flow Cytometry. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50792-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
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Linden MD, Whittaker P, Frelinger AL, Barnard MR, Michelson AD, Przyklenk K. Preconditioning ischemia attenuates molecular indices of platelet activation-aggregation. J Thromb Haemost 2006; 4:2670-7. [PMID: 16995902 DOI: 10.1111/j.1538-7836.2006.02228.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Previous studies have shown that ischemic preconditioning (PC) not only limits infarct size, but also improves arterial patency in models of recurrent thrombosis. We hypothesize that this enhanced patency is presumably because of a PC-induced attenuation of platelet-mediated thrombosis. However, there is, at present, no direct evidence that PC acts on the platelets per se and favorably down-regulates platelet reactivity. OBJECTIVES Our goal was to test the concept that PC ischemia attenuates molecular indices of platelet activation-aggregation. METHODS Anesthetized dogs were randomly assigned to receive 10 min of PC ischemia followed by 10 min of reperfusion or a time-matched control period. Spontaneous recurrent coronary thrombosis was then initiated in all dogs by injury + stenosis of the left anterior descending coronary artery. Coronary flow was monitored for 3 h poststenosis, and molecular indices of platelet activation-aggregation were quantified by whole blood flow cytometry. RESULTS Coronary patency was, as expected, better-maintained following injury + stenosis in the PC group vs. controls (53% +/- 5%* vs. 23% +/- 5% of baseline flow, respectively; *P < 0.05). Moreover, PC was accompanied by: (i) a significant down-regulation of platelet-fibrinogen binding and formation of neutrophil-platelet aggregates (112% +/- 14%* vs. 177% +/- 21% and 107% +/- 8%* vs. 155% +/- 19% of baseline values in PC vs. control groups); and (ii) a trend towards a reduction in platelet P-selectin expression (148% +/- 12% vs. 190% +/- 21% of baseline; *P < 0.05 and P = 0.09 vs. control). CONCLUSION These data provide novel, direct evidence in support of the concept that ischemic PC attenuates molecular indices of platelet activation-aggregation.
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Affiliation(s)
- M D Linden
- Center for Platelet Function Studies, University of Massachusetts Medical School, Worcester, MA 01655, USA
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