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Soluble glycoprotein VI is a predictor of major bleeding in patients with suspected heparin-induced thrombocytopenia. Blood Adv 2021; 4:4327-4332. [PMID: 32915974 DOI: 10.1182/bloodadvances.2020002861] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 08/05/2020] [Indexed: 02/06/2023] Open
Abstract
We have shown that patients with suspected heparin-induced thrombocytopenia (HIT) have a high incidence of major bleeding. Recent studies have implicated elevated soluble glycoprotein VI (sGPVI) levels as a potential risk factor for bleeding. We sought to determine if elevated sGPVI plasma levels are associated with major bleeding events in patients with suspected HIT. We used a cohort of 310 hospitalized adult patients with suspected HIT who had a blood sample collected at the time HIT was suspected. Plasma sGPVI levels were measured by using enzyme-linked immunosorbent assay. Patients were excluded who had received a platelet transfusion within 1 day of sample collection because of the high levels of sGPVI in platelet concentrates. We assessed the association of sGPVI (high vs low) with International Society on Thrombosis and Haemostasis major bleeding events by multivariable logistic regression, adjusting for other known risk factors for bleeding. Fifty-four patients were excluded due to recent platelet transfusion, leaving 256 patients for analysis. Eighty-nine (34.8%) patients had a major bleeding event. Median sGPVI levels were significantly elevated in patients with major bleeding events compared with those without major bleeding events (49.09 vs 31.93 ng/mL; P < .001). An sGPVI level >43 ng/mL was independently associated with major bleeding after adjustment for critical illness, sepsis, cardiopulmonary bypass surgery, and degree of thrombocytopenia (adjusted odds ratio, 2.81; 95% confidence interval, 1.51-5.23). Our findings suggest that sGPVI is associated with major bleeding in hospitalized patients with suspected HIT. sGPVI may be a novel biomarker to predict bleeding risk in patients with suspected HIT.
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Shedding of soluble glycoprotein VI is neither affected by animal-derived antibeta-2-glycoprotein 1 antibodies nor IgG fractions from patients with systemic lupus erythematosus. Blood Coagul Fibrinolysis 2020; 31:258-263. [DOI: 10.1097/mbc.0000000000000909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Luu S, Woolley IJ, Andrews RK. Platelet phenotype and function in the absence of splenic sequestration (Review). Platelets 2020; 32:47-52. [PMID: 32106750 DOI: 10.1080/09537104.2020.1732322] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The spleen, in addition to its role in immunity, plays key roles in erythrocyte maintenance and platelet sequestration. Loss of the spleen via splenectomy occurs in approximately 6.4 to 7.1 per 100 000 people per year globally, commonly as a life-saving emergency procedure in trauma and a therapeutic procedure in hematological and hematological malignant conditions. It is associated with increased risk of life-threatening infection and thromboembolism, presumably via loss of splenic function, but the underlying mechanisms behind post-splenectomy thromboembolism are unclear. The splenectomized individual has a two-fold risk of thromboembolism as compared to non-splenectomized individuals and the risk of thromboembolism is elevated both post-operatively and in the longer term. Although those splenectomized for hematological conditions or hematological malignant conditions are at highest risk for thromboembolism, an increase in thromboembolic outcomes is also observed amongst individuals splenectomized for trauma, suggesting underlying disease state is only a partial factor. Although the physiological role of the splenic platelet pool on platelets is unclear, platelet changes after splenectomy suggest that the spleen may play a role in maintaining platelet quality and function. In hypersplenic conditions, sequestration can increase to sequester up to 72% of the total platelet mass. Following splenectomy, a thrombocytosis is commonly seen secondary to the loss of the ability to sequester platelets. Abnormal platelet quality and function have been observed as a consequence of splenectomy. These platelet defects seen after splenectomy may likely contribute to the increase in post-splenectomy thromboembolism. Here we draw upon the literature to characterize the post-splenectomy platelet and its potential role in post-splenectomy thromboembolism.
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Affiliation(s)
- Sarah Luu
- Australian Centre for Blood Diseases, Monash University , Melbourne, Australia
| | - Ian J Woolley
- Centre for Inflammatory Diseases, Monash University , Melbourne, Australia.,Monash Infectious Diseases, Monash Health , Melbourne, Australia
| | - Robert K Andrews
- Australian Centre for Blood Diseases, Monash University , Melbourne, Australia
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Weller CD, Gardiner EE, Arthur JF, Southey M, Andrews RK. Autologous platelet-rich plasma for healing chronic venous leg ulcers: Clinical efficacy and potential mechanisms. Int Wound J 2019; 16:788-792. [PMID: 30864220 PMCID: PMC7949463 DOI: 10.1111/iwj.13098] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/26/2019] [Indexed: 12/13/2022] Open
Abstract
The overall quality of evidence of autologous platelet-rich plasma (PRP) for treating chronic wounds remains low. While further well-designed clinical studies are clearly required to convincingly demonstrate the efficacy of autologous PRP in improved healing of venous leg ulcers (VLUs) and other chronic wounds, there is also an increasing need to better define the underlying mechanisms of action and whether positive outcomes can be predicted based on the analysis of PRP. This brief review will discuss the current understanding of autologous PRP in VLUs and whether molecular evaluation of PRP at the time of collection could potentially be informative to clinical outcomes. Benefits of the autologous PRP treatment strategy include that PRP is easily accessible and is relatively inexpensive and safe. Better understanding of the mechanisms involved could improve treatment, enable supplementation, and/or lead to gains in product development. Analysis of PRP could also add value to future clinical trials on efficacy and potentially personalised treatment regimens.
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Affiliation(s)
- Carolina D. Weller
- School of Nursing and MidwiferyMonash UniversityMelbourneVictoriaAustralia
| | - Elizabeth E. Gardiner
- Department of Cancer Biology and Therapeutics, John Curtin School of Medical ResearchAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Jane F. Arthur
- Australian Centre for Blood DiseasesMonash UniversityMelbourneVictoriaAustralia
| | - Melissa Southey
- Precision MedicineMonash UniversityMelbourneVictoriaAustralia
- Cancer Epidemiology and Intelligence DivisionCancer Council VictoriaMelbourneVictoriaAustralia
- Department of Clinical PathologyThe University of MelbourneMelbourneVictoriaAustralia
| | - Robert K. Andrews
- Australian Centre for Blood DiseasesMonash UniversityMelbourneVictoriaAustralia
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5
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Luu S, Gardiner EE, Andrews RK. Bone Marrow Defects and Platelet Function: A Focus on MDS and CLL. Cancers (Basel) 2018; 10:E147. [PMID: 29783667 PMCID: PMC5977120 DOI: 10.3390/cancers10050147] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/11/2018] [Accepted: 05/16/2018] [Indexed: 12/16/2022] Open
Abstract
The bloodstream typically contains >500 billion anucleate circulating platelets, derived from megakaryocytes in the bone marrow. This review will focus on two interesting aspects of bone marrow dysfunction and how this impacts on the quality of circulating platelets. In this regard, although megakaryocytes are from the myeloid lineage leading to granulocytes (including neutrophils), erythrocytes, and megakaryocytes/platelets, recent evidence has shown that defects in the lymphoid lineage leading to B cells, T cells, and natural killer (NK) cells also result in abnormal circulating platelets. Current evidence is limited regarding whether this latter phenomenon might potentially arise from (a) some form of as-yet-undetected defect common to both lineages; (b) adverse interactions occurring between cells of different lineages within the bone marrow environment; and/or (c) unknown disease-related factor(s) affecting circulating platelet receptor expression/function after their release from megakaryocytes. Understanding the mechanisms underlying how both myeloid and lymphoid lineage bone marrow defects lead to dysfunction of circulating platelets is significant because of the potential diagnostic and predictive value of peripheral platelet analysis for bone marrow disease progression, the additional potential effects of new anti-cancer drugs on platelet function, and the critical role platelets play in regulation of bleeding risk, inflammation, and innate immunity.
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Affiliation(s)
- Sarah Luu
- Australian Centre for Blood Diseases, Monash University, Melbourne, VIC 3004, Australia.
| | - Elizabeth E Gardiner
- ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia.
| | - Robert K Andrews
- Australian Centre for Blood Diseases, Monash University, Melbourne, VIC 3004, Australia.
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7
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Abstract
Proteolytic shedding of the extracellular ectodomain of platelet receptors provides a key mechanism for irreversible loss of ligand-binding capacity, and for regulating platelet function in health and disease. Platelets derived from megakaryocytes are small anucleate cells in peripheral blood, with the ability to rapidly adhere, become activated, and secrete an array of procoagulant and proinflammatory factors at sites of vascular injury or disease, and to form a platelet aggregate (thrombus) which is not only critical in normal hemostasis and wound healing, but in atherothrombotic diseases including myocardial infarction and ischemic stroke. Basic mechanisms of receptor shedding on platelets have important distinctions from how receptors on other cell types might be shed, in that shedding is rapidly initiated (within seconds to minutes) and occurs under altered shear conditions encountered in flowing blood or experimentally ex vivo. This review will consider the key components of platelet receptor shedding, that is, the receptor with relevant cleavage site, the (metallo)proteinase or sheddase and how its activity is regulated, and the range of known regulatory factors that control platelet receptor shedding including receptor-associated molecules such as calmodulin, factors controlling sheddase surface expression and activity, and other elements such as shear stress, plasma membrane properties, cellular activation status or age. Understanding these basic mechanisms of platelet receptor shedding is significant in terms of utilizing receptor surface expression or soluble proteolytic fragments as platelet-specific biomarkers and/or ultimately therapeutic targeting of these mechanisms to control platelet reactivity and function.
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Affiliation(s)
- Robert K Andrews
- a Australian Centre for Blood Diseases , Monash University , Melbourne , Australia 3004.,b Department of Cancer Biology and Therapeutics, the John Curtin School of Medical Research , Australian National University , Canberra , Australia 2600
| | - Elizabeth E Gardiner
- a Australian Centre for Blood Diseases , Monash University , Melbourne , Australia 3004.,b Department of Cancer Biology and Therapeutics, the John Curtin School of Medical Research , Australian National University , Canberra , Australia 2600
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Metharom P, Berndt MC, Baker RI, Andrews RK. Current state and novel approaches of antiplatelet therapy. Arterioscler Thromb Vasc Biol 2015; 35:1327-38. [PMID: 25838432 DOI: 10.1161/atvbaha.114.303413] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 03/19/2015] [Indexed: 01/22/2023]
Abstract
An unresolved problem with clinical use of antiplatelet therapy is that a significant number of individuals either still get thrombosis or run the risk of life-threatening bleeding. Antiplatelet drugs are widely used clinically, either chronically for people at risk of athero/thrombotic disease or to prevent thrombus formation during surgery. However, a subpopulation may be resistant to standard doses, while the platelet targets of these drugs are also critical for the normal hemostatic function of platelets. In this review, we will briefly examine current antiplatelet therapy and existing targets while focusing on new potential approaches for antiplatelet therapy and improved monitoring of effects on platelet reactivity in individuals, ultimately to improve antithrombosis with minimal bleeding. Primary platelet adhesion-signaling receptors, glycoprotein (GP)Ib-IX-V and GPVI, that bind von Willebrand factor/collagen and other prothrombotic factors are not targeted by drugs in clinical use, but they are of particular interest because of their key role in thrombus formation at pathological shear.
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Affiliation(s)
- Pat Metharom
- From the Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia (P.M., M.C.B); Western Australian Centre for Thrombosis and Haemostasis, Murdoch University, Perth, Western Australia, Australia (R.I.B.); and Australian Centre for Blood Diseases, Department of Clinical Haematology, Monash University, Melbourne, Victoria, Australia (R.K.A.)
| | - Michael C Berndt
- From the Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia (P.M., M.C.B); Western Australian Centre for Thrombosis and Haemostasis, Murdoch University, Perth, Western Australia, Australia (R.I.B.); and Australian Centre for Blood Diseases, Department of Clinical Haematology, Monash University, Melbourne, Victoria, Australia (R.K.A.).
| | - Ross I Baker
- From the Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia (P.M., M.C.B); Western Australian Centre for Thrombosis and Haemostasis, Murdoch University, Perth, Western Australia, Australia (R.I.B.); and Australian Centre for Blood Diseases, Department of Clinical Haematology, Monash University, Melbourne, Victoria, Australia (R.K.A.)
| | - Robert K Andrews
- From the Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia (P.M., M.C.B); Western Australian Centre for Thrombosis and Haemostasis, Murdoch University, Perth, Western Australia, Australia (R.I.B.); and Australian Centre for Blood Diseases, Department of Clinical Haematology, Monash University, Melbourne, Victoria, Australia (R.K.A.)
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Murphy DA, Hockings LE, Andrews RK, Aubron C, Gardiner EE, Pellegrino VA, Davis AK. Extracorporeal membrane oxygenation-hemostatic complications. Transfus Med Rev 2014; 29:90-101. [PMID: 25595476 DOI: 10.1016/j.tmrv.2014.12.001] [Citation(s) in RCA: 252] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 10/19/2014] [Accepted: 12/03/2014] [Indexed: 12/17/2022]
Abstract
The use of extracorporeal membrane oxygenation (ECMO) support for cardiac and respiratory failure has increased in recent years. Improvements in ECMO oxygenator and pump technologies have aided this increase in utilization. Additionally, reports of successful outcomes in supporting patients with respiratory failure during the 2009 H1N1 pandemic and reports of ECMO during cardiopulmonary resuscitation have led to increased uptake of ECMO. Patients requiring ECMO are a heterogenous group of critically ill patients with cardiac and respiratory failure. Bleeding and thrombotic complications remain a leading cause of morbidity and mortality in patients on ECMO. In this review, we describe the mechanisms and management of hemostatic, thrombotic and hemolytic complications during ECMO support.
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Affiliation(s)
- Deirdre A Murphy
- Department of Intensive Care and Hyperbaric Medicine, Alfred Hospital, Melbourne, Australia; Department of Epidemiology and Preventative Medicine, School of Public Health, Monash University, Melbourne, Australia.
| | - Lisen E Hockings
- Department of Intensive Care and Hyperbaric Medicine, Alfred Hospital, Melbourne, Australia; Department of Epidemiology and Preventative Medicine, School of Public Health, Monash University, Melbourne, Australia
| | - Robert K Andrews
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
| | - Cecile Aubron
- ANZIC Research Centre, Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia; Transfusion Research Unit, Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
| | | | - Vincent A Pellegrino
- Department of Intensive Care and Hyperbaric Medicine, Alfred Hospital, Melbourne, Australia; Department of Epidemiology and Preventative Medicine, School of Public Health, Monash University, Melbourne, Australia
| | - Amanda K Davis
- Department of Haematology, Alfred Hospital Melbourne, Australia
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Platelet receptor expression and shedding: glycoprotein Ib-IX-V and glycoprotein VI. Transfus Med Rev 2014; 28:56-60. [PMID: 24674813 DOI: 10.1016/j.tmrv.2014.03.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/04/2014] [Accepted: 03/04/2014] [Indexed: 01/13/2023]
Abstract
Quantity, quality, and lifespan are 3 important factors in the physiology, pathology, and transfusion of human blood platelets. The aim of this review is to discuss the proteolytic regulation of key platelet-specific receptors, glycoprotein(GP)Ib and GPVI, involved in the function of platelets in hemostasis and thrombosis, and nonimmune or immune thrombocytopenia. The scope of the review encompasses the basic science of platelet receptor shedding, practical aspects related to laboratory analysis of platelet receptor expression/shedding, and clinical implications of using the proteolytic fragments as platelet-specific biomarkers in vivo in terms of platelet function and clearance. These topics can be relevant to platelet transfusion regarding both changes in platelet receptor expression occurring ex vivo during platelet storage and/or clinical use of platelets for transfusion. In this regard, quantitative analysis of platelet receptor profiles on blood samples from individuals could ultimately enable stratification of bleeding risk, discrimination between causes of thrombocytopenia due to impaired production vs enhanced clearance, and monitoring of response to treatment prior to change in platelet count.
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