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Porcelijn L, Schmidt DE, van der Schoot CE, Vidarsson G, de Haas M, Kapur R. Anti-glycoprotein Ibα autoantibodies do not impair circulating thrombopoietin levels in immune thrombocytopenia patients. Haematologica 2020; 105:e172-e174. [PMID: 31296573 PMCID: PMC7109722 DOI: 10.3324/haematol.2019.228908] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Leendert Porcelijn
- Department of Immunohematology Diagnostics, Sanquin Diagnostic Services, Amsterdam
| | - David E Schmidt
- Sanquin Research, Department of Experimental Immunohematology and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam
| | - C Ellen van der Schoot
- Sanquin Research, Department of Experimental Immunohematology and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam
| | - Gestur Vidarsson
- Sanquin Research, Department of Experimental Immunohematology and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam
| | - Masja de Haas
- Department of Immunohematology Diagnostics, Sanquin Diagnostic Services, Amsterdam
- Sanquin Research, Center for Clinical Transfusion Research and Jon J van Rood Center for Clinical Transfusion Science, Leiden University Medical Center, Leiden
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leide the Netherlands
| | - Rick Kapur
- Sanquin Research, Department of Experimental Immunohematology and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam
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2
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Porcelijn L, Huiskes E, Onderwater-Van Den Hoogen L, Folman CC, Zwaginga JJ, De Haas M. Plasma thrombopoietin levels as additional tool in clinical management of thrombocytopenic neonates. Platelets 2019; 31:62-67. [DOI: 10.1080/09537104.2019.1572877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Leendert Porcelijn
- Department of Immunohematology Diagnostic Services Amsterdam, Sanquin Diagnostic Services, Amsterdam, The Netherlands
| | - Elly Huiskes
- Department of Immunohematology Diagnostic Services Amsterdam, Sanquin Diagnostic Services, Amsterdam, The Netherlands
| | | | - Claudia C Folman
- Department of Immunohematology Diagnostic Services Amsterdam, Sanquin Diagnostic Services, Amsterdam, The Netherlands
| | - Jaap Jan Zwaginga
- Department of Immuno-hematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
- Center for Clinical Transfusion Research, Sanquin Research, Leiden and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Masja De Haas
- Department of Immunohematology Diagnostic Services Amsterdam, Sanquin Diagnostic Services, Amsterdam, The Netherlands
- Department of Immuno-hematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
- Center for Clinical Transfusion Research, Sanquin Research, Leiden and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
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3
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Cho J, Kim H, Song J, Cheong JW, Shin JW, Yang WI, Kim HO. Platelet storage induces accelerated desialylation of platelets and increases hepatic thrombopoietin production. J Transl Med 2018; 16:199. [PMID: 30021591 PMCID: PMC6052694 DOI: 10.1186/s12967-018-1576-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/13/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Stored platelets undergo deleterious changes, referred to as platelet storage lesions (PSLs), which accelerate the desialylation of platelets and result in their phagocytosis and clearance by hepatic macrophages. Recent studies have reported that Ashwell-Morell receptor binds to desialylated platelets, thereby inducing hepatic thrombopoietin (TPO) production in a mouse model. Therefore, this study aimed to demonstrate these relationships between PSL and hepatic TPO production in human study. METHODS Platelet concentrates (PCs) were obtained from 5 healthy volunteers and the remaining were discarded samples from the blood bank. PCs were divided into two halves, and stored either at 22 or 4 °C. Experiments were conducted using serial samples. Desialylation was assessed using flow cytometry, and structural changes were visualized using electron microscopy. Following co-culture of HepG2 cells (HB-8065, ATCC) with isolated platelets, hepatic TPO production was determined using real-time quantitative polymerase chain reaction and the supernatant TPO level was measured using a Luminex kit. RESULTS For 5 days of storage duration, platelet counts were not influenced by the storage conditions, but the degree of desialylation was proportional to the storage duration. Significant changes in the platelet surface and structure according to storage conditions were noted in electron microscopy. HepG2 cells incubated with aged platelets expressed more TPO mRNA, and supernatant TPO levels were proportional to the storage duration. Refrigeration also influenced on the results of this study, but they were not statistically significant. CONCLUSIONS This is the first study to demonstrate that, in vitro, aging and refrigeration affect the integrity of human platelets, resulting in induction of hepatic TPO mRNA and protein expression.
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Affiliation(s)
- Jooyoung Cho
- Department of Laboratory Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722 South Korea
- Department of Laboratory Medicine, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | - Hyunkyung Kim
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Jaewoo Song
- Department of Laboratory Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722 South Korea
| | - June-Won Cheong
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Jeong Won Shin
- Department of Laboratory Medicine, Soonchunhyang University School of Medicine, Seoul, South Korea
| | - Woo Ick Yang
- Department of Pathology, Yonsei University College of Medicine, Seoul, South Korea
| | - Hyun Ok Kim
- Department of Laboratory Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722 South Korea
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4
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Vicente-Ayuso C, Papadopoulos P, Villa-Fajardo M, Prieto B, Álvarez-Carmona AM, Mateo-Morales M, Pérez-López C, Peña-Cortijo A, Polo-Zarzuela M, Sáez I, Martín MP, Benavente-Cuesta C, González-Fernández A, Martínez-Martínez R, Zwaginga JJ, Seghatchian J, Gutiérrez L. Identification of underlying and transfusion-related platelet qualitative alterations in the hemato-oncologic patient. Transfus Apher Sci 2017; 56:756-768. [PMID: 28970003 DOI: 10.1016/j.transci.2017.08.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Hemato-oncologic patients with chemotherapy-induced thrombocytopenia are one of the populations receiving platelet transfusions. The general practice with these patients is to give prophylactic platelet transfusions when platelet counts fall below 10×109PLT/L. However, in more than 40% of these patients, platelet transfusion does not prevent bleeding. The reason of the low efficacy of platelet transfusion in the context of chemotherapy patients is not entirely understood. We therefore aimed at immunophenotyping the expression of platelet surface and activation markers and thrombopoietin levels from hemato-oncologic patients before and after transfusion. A more detailed follow-up was performed in three patients that underwent autologous bone marrow transplantation. As previously reported, basal platelet activation was observed in hemato-oncologic patients. Based on flow cytometry parameters, i.e. the percentage of positivity and mean fluorescence intensity (MFI) distribution, our data provide an additional interpretation of platelet acquired qualitative changes in the hemato-oncologic patient. From our results we propose: first, the underlying activation of platelets in the hemato-oncologic patient is accompanied by loss of expression of the platelet receptors that are susceptible to protease-mediated shedding; second, soon after transfusion, the newly circulating donor platelets show additional activation, which may result in subsequent platelet receptor recycling and potential accelerated clearance of these activated platelets. In conclusion, the immunophenotype of circulating platelets changes after prophylactic platelet transfusion. Next to platelet count increment, exploration of this immunophenotype might help to explain transfusion refractory bleeding in hemato-oncologic patients. Eventually this may lead to personalization and improvement of the present platelet transfusion support regime.
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Affiliation(s)
- Carmen Vicente-Ayuso
- Department of Hematology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Petros Papadopoulos
- Department of Hematology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - María Villa-Fajardo
- Department of Hematology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Blanca Prieto
- Department of Hematology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | | | - Marta Mateo-Morales
- Servicio de Hematología y Hemoterapia, Hospital Clínico San Carlos, Madrid, Spain
| | - Cristina Pérez-López
- Servicio de Hematología y Hemoterapia, Hospital Clínico San Carlos, Madrid, Spain
| | | | - Marta Polo-Zarzuela
- Servicio de Hematología y Hemoterapia, Hospital Clínico San Carlos, Madrid, Spain
| | - Isabel Sáez
- Servicio de Hematología y Hemoterapia, Hospital Clínico San Carlos, Madrid, Spain
| | - María Paz Martín
- Department of Hematology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Celina Benavente-Cuesta
- Department of Hematology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | - Ataúlfo González-Fernández
- Department of Hematology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain
| | | | - Jaap Jan Zwaginga
- Center for Clinical Transfusion Research, Sanquin Research, Leiden, The Netherlands; Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Jerard Seghatchian
- International Consultancy in Blood Components Quality/Safety Improvement and DDR Strategy, London, United Kingdom.
| | - Laura Gutiérrez
- Department of Hematology, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Madrid, Spain.
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5
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Affiliation(s)
- Calin I Prodan
- Department of Neurology, University of Oklahoma Health Sciences Center and Veterans Administration Medical Center, Oklahoma City, OK 73104, USA.
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6
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Abstract
Platelet transfusions are a critical component of the supportive care for patients receiving intensive therapy for hematologic malignancies. The platelet count "triggering" prophylactic transfusion has decreased over the years, and studies comparing a prophylactic versus a therapeutic transfusion approach are in progress. The evidence supporting the need for platelet transfusions prior to different invasive procedures is reviewed. Lastly, studies evaluating the use of thrombopoietic stimulating agents to reduce hemorrhage and decrease the need for platelet transfusions are discussed. To date, there is no evidence that this approach is of clinical utility.
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Affiliation(s)
- Jason Valent
- Division of Hematology/Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201, USA.
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7
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Kline A, Mackley A, Taylor SM, McKenzie SE, Paul DA. Thrombopoietin following transfusion of platelets in preterm neonates. Platelets 2009; 19:428-31. [PMID: 18925510 DOI: 10.1080/09537100802220476] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Thrombocytopenia is common in the neonatal intensive care unit. Transfusion of platelets is often required. The purpose of our study was to determine changes in thrombopoietin (Tpo) following transfusion of platelets in preterm neonates. Preterm neonates undergoing platelet transfusion were randomized to receive a transfusion volume of either 10 or 15 ml/kg. Blood was obtained for Tpo measurement pre-transfusion, one and 24 hours post-transfusion. Platelet Factor 4 (PF4) was also measured to quantify platelet activation. Statistical analysis was performed using repeated measures ANOVA, and Mann-Whitney U test as appropriate. Ten infants were enrolled in each group. Gestational age, birth weight, etiology of thrombocytopenia, and timing of transfusion did not differ between the 10 and 15 ml/kg groups. There were no differences between the groups in platelet count prior to and/or following transfusion. Both transfusion volumes were equally well tolerated. Tpo and PF4 did not differ between groups at any of the study time points. When both groups were analysed together, Tpo dropped 43% (95% confidence 37-49%, p = 0.01) 1-hour post compared to pre-transfusion. In conclusion the observed decrease in Tpo following platelet transfusion suggests that Tpo kinetics in neonates is similar to adults following transfusion. PF4 was not affected by transfusion. There was not an increase in platelet count following transfusion volume of 15 ml/kg compared to 10 ml/kg.
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Affiliation(s)
- Alex Kline
- Department of Pediatrics, Section of Neonatology, Fairfax Hospital, Fairfax, Virginia, USA
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8
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Lee JJ, Kang SY, Lee WI. The Analysis of Thrombopoietin and Clinical Parameters as a Marker for Disease Progression in Patients with Multiple Myeloma. Ann Lab Med 2009; 29:82-8. [DOI: 10.3343/kjlm.2009.29.1.82] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Jae Jin Lee
- Devision of Hematology & Medical Oncology, Department of Internal Medicine, Kyung Hee University College of Medicine, Seoul, Korea
| | - So Young Kang
- Department of Laboratory Medicine, Kyung Hee University College of Medicine, Seoul, Korea
| | - Woo-In Lee
- Department of Laboratory Medicine, Kyung Hee University College of Medicine, Seoul, Korea
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9
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Incomplete restoration of Mpl expression in the mpl-/- mouse produces partial correction of the stem cell-repopulating defect and paradoxical thrombocytosis. Blood 2008; 113:1778-85. [PMID: 18796624 DOI: 10.1182/blood-2007-11-124859] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Expression of Mpl is restricted to hematopoietic cells in the megakaryocyte lineage and to undifferentiated progenitors, where it initiates critical cell survival and proliferation signals after stimulation by its ligand, thrombopoietin (TPO). As a result, a deficiency in Mpl function in patients with congenital amegakaryocytic thrombocytopenia (CAMT) and in mpl(-/-) mice produces profound thrombocytopenia and a severe stem cell-repopulating defect. Gene therapy has the potential to correct the hematopoietic defects of CAMT by ectopic gene expression that restores normal Mpl receptor activity. We rescued the mpl(-/-) mouse with a transgenic vector expressing mpl from the promoter elements of the 2-kb region of DNA just proximal to the natural gene start site. Transgene rescued mice exhibit thrombocytosis but only partial correction of the stem cell defect. Furthermore, they show very low-level expression of Mpl on platelets and megakaryocytes, and the transgene-rescued megakaryocytes exhibit diminished TPO-dependent kinase phosphorylation and reduced platelet production in bone marrow chimeras. Thrombocytosis is an unexpected consequence of reduced Mpl expression and activity. However, impaired TPO homeostasis in the transgene-rescued mice produces elevated plasma TPO levels, which serves as an unchecked stimulus to drive the observed excessive megakaryocytopoiesis.
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10
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Abstract
This article provides guidelines for the appropriate use of platelet transfusions to reduce unnecessary transfusions, thereby avoiding transfusion-related risks to the patients and the costs of platelet therapy. Platelet products available for transfusion are whole blood derived platelet concentrates and apheresis platelets. Leukoreduced platelets can be used to reduce platelet alloimmunization, cytomegalovirus transmission, and febrile transfusion reactions, while gamma irradiation prevents transfusion-associated graftversus-host disease. Other topics discussed are the expected response to transfused platelets and reasons for poor responses related to alloimmunization, underlying disease state, clinical conditions, and drugs. Appropriate transfusion guidelines based on pretransfusion platelet count, platelet dose, and whether the transfusion is prophylactic or therapeutic are outlined. Identification, prevention, and management of adverse consequences of platelet transfusions and platelet refractoriness are discussed.
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11
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Slichter SJ. Evidence-based platelet transfusion guidelines. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2007; 2007:172-178. [PMID: 18024626 DOI: 10.1182/asheducation-2007.1.172] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Transfused platelets (plts) are either pooled random-donor platelet (plt) concentrates or single-donor apheresis plts. When stored for 5 days, all of these products are equally efficacious. A 10,000/microL prophylactic plt transfusion trigger has been documented to be both hemostatically efficacious and cost effective in reducing plt transfusion requirements. The optimal plt dose/transfusion is being evaluated in an ongoing clinical trial. Therapeutic plt transfusions to control or prevent bleeding with trauma or surgical procedures require higher transfusion triggers of 100,000/microL for neurosurgical procedures and between 50,000/microL and 100,000/microL for other invasive procedures or trauma. Leukoreduction has been documented to reduce plt alloimmunization rates, cytomegalovirus (CMV) transmission by transfusion, and febrile transfusion reactions. Whether it reduces immunomodulatory effects of transfusion (i.e., decreases infection rates and cancer recurrence) is still controversial, as is universal leukoreduction. Poor responses to plt transfusions are often multifactorial. For alloimmune plt refractoriness, HLA matching, cross-matching, and identification of the specificity of the patient's antibodies with avoidance of mismatched donor antigens are all equally effective in identifying compatible plts for transfusion. Other causes of poor plt responses are splenomegaly, ABO mismatching, females with 2 or more pregnancies and males, use of heparin or amphotericin, bleeding, fever, graft-vs-host disease (GVHD), and vaso-occlusive disease (VOD).
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Affiliation(s)
- Sherrill J Slichter
- Platelet Transfusion Research, Puget Sound Blood Center, 921 Terry Avenue, Seattle, WA 98104-1256, USA.
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12
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Rios R, Sangro B, Herrero I, Quiroga J, Prieto J. The role of thrombopoietin in the thrombocytopenia of patients with liver cirrhosis. Am J Gastroenterol 2005; 100:1311-6. [PMID: 15929762 DOI: 10.1111/j.1572-0241.2005.41543.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Thrombocytopenia is a common disorder among cirrhotics that has been traditionally explained by splenic platelet pooling and destruction. Thrombopoietin (TPO), the main stimuli for thrombopoiesis is produced primarily in the liver and degraded by circulating platelets, but its role in the thrombocytopenia of liver cirrhosis is not well understood. The main goal of this study is to clarify the role of TPO in the pathogenesis of thrombocytopenia in cirrhosis. METHODS The relation among TPO, platelet count, spleen size, portal hypertension, and liver function was studied in 33 cirrhotic patients before and after either partial splenic embolization or liver transplantation. RESULTS Cirrhotics with thrombocytopenia had lower serum TPO levels than healthy controls (median values (interquartile range: ICR) were 120.7 (42.0-191.6) vs 756.4 (527.0-965.1) pg/mL, respectively; p<0.001). Among cirrhotics with thrombocytopenia, serum TPO was related to spleen size (rho=-0.387, p=0.046), but not to platelet count as occurs physiologically. After partial splenic embolization, TPO and platelet count increased significantly and the physiological relation between TPO and platelet count was restored (rho=-0.665, p=0.026). Similar results were observed after liver transplantation. CONCLUSIONS Our results suggest that besides impaired production in the failing liver, an increased TPO degradation by platelets sequestered in the congested spleen may contribute to thrombocytopenia in cirrhotic patients.
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Affiliation(s)
- Raquel Rios
- Liver Unit, Clinica Universitaria de Navarra, Pamplona, Spain
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13
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Tijssen MR, van der Schoot CE, Voermans C, Zwaginga JJ. The (patho)physiology of megakaryocytopoiesis: from thrombopoietin in diagnostics and therapy to ex vivo generated cellular products. Vox Sang 2005; 87 Suppl 2:52-5. [PMID: 15209879 DOI: 10.1111/j.1741-6892.2004.00500.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- M R Tijssen
- Department of Experimental Immunohematology, Sanquin Research, location CLB, Academical Medical Centre, Amsterdam, the Netherlands
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14
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Valeri CR, Ragno G, Marks PW, Kuter DJ, Rosenberg RD, Stossel TP. Effect of thrombopoietin alone and a combination of cytochalasin B and ethylene glycol bis(β-aminoethyl ether) N,N′-tetraacetic acid-AM on the survival and function of autologous baboon platelets stored at 4°C for as long as 5 days. Transfusion 2004; 44:865-70. [PMID: 15157253 DOI: 10.1111/j.1537-2995.2004.03326.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND PLTs stored at 22 degrees C have the potential for bacterial contamination, a problem that could be reduced by 4 degrees C storage. Nevertheless, PLTs stored at 4 degrees C exhibit a significantly reduced life span. This study was performed to determine whether treatment of PLTs with thrombopoietin or cytochalasin B plus ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetic acid (EGTA)-AM could prevent exponential loss of PLTs stored at 4 degrees C. STUDY DESIGN AND METHODS Autologous baboon PLTs were stored at 22 or 4 degrees C. The 4 degrees C stored PLTs were treated with 1.5 ng per mL thrombopoietin, with 1 micro mol per L cytochalasin B, and 80 micromol per L EGTA-AM (cyto-EGTA) or not treated and labeled with (111)In-oxine to study their in vivo recovery and life span. PLT function was assessed by correction of an aspirin-induced prolonged bleeding time. Aggregation responses and morphology were also assessed. RESULTS PLTs stored at 22 degrees C had normal in vivo recovery and linear survival. PLTs stored at 4 degrees C, whether or not they were treated with thrombopoietin, had normal recovery and exponential survival. Aggregation of cyto-EGTA-treated PLTs was similar for PLTs stored at 4 degrees C and fresh PLTs, but decreased in PLTs stored at 22 degrees C for 5 days. The addition of cyto-EGTA to PLTs before 4 degrees C storage inhibited morphologic changes that occurred in PLTs stored at 22 degrees C and cold-induced PLT clumping, but did not prevent exponential disappearance of the PLTs. CONCLUSION Addition of thrombopoietin or cyto-chalasin B and EGTA-AM to PLTs before 4 degrees C storage did not prevent exponential loss of PLTs.
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Affiliation(s)
- C Robert Valeri
- Naval Blood Research Laboratory, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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15
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Porcelijn L, Folman CC, de Haas M, Kanhai HHH, Murphy MF, von dem Borne AEGK, Bussel JB. Fetal and neonatal thrombopoietin levels in alloimmune thrombocytopenia. Pediatr Res 2002; 52:105-8. [PMID: 12084855 DOI: 10.1203/00006450-200207000-00019] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Thrombopoietin (Tpo) is the main hematopoietic growth factor for platelet production. Plasma Tpo levels in autoimmune thrombocytopenic patients are normal or slightly elevated. Although thrombocytopenia exists, Tpo levels are not increased because the produced megakaryocytes and platelets can bind circulating Tpo, thereby normalizing Tpo levels. In this study, plasma samples from fetuses and neonates with neonatal alloimmune thrombocytopenia (NAIT), a different form of immune thrombocytopenia, were measured. Umbilical cord samples from 50 fetuses before treatment because of severe thrombocytopenia and 51 fetuses after treatment, and peripheral blood samples of 21 untreated newborns with NAIT were analyzed. As controls, plasma Tpo levels were determined in 21 umbilical cord samples of 14 nonthrombocytopenic fetuses with hemolytic disease resulting from red blood cell alloimmunization and in umbilical cord samples of 51 healthy newborns. The values were also compared with the plasma Tpo levels in 193 healthy adults. Mean Tpo levels from the groups of fetuses and neonates, including both NAIT and control plasma, were slightly but significantly elevated compared with levels in healthy adults. Tpo levels in NAIT samples were not significantly different from the levels in hemolytic disease samples or in samples from healthy newborns. Thus, as in autoimmune thrombocytopenic patients, normal Tpo levels are present in NAIT patients.
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Affiliation(s)
- L Porcelijn
- Sanquin Diagnostics, Amsterdam, The Netherlands.
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16
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Scheding S, Bergmann M, Shimosaka A, Wolff P, Driessen C, Rathke G, Jaschonek K, Brugger W, Kanz L. Human plasma thrombopoietin levels are regulated by binding to platelet thrombopoietin receptors in vivo. Transfusion 2002; 42:321-7. [PMID: 11961237 DOI: 10.1046/j.1537-2995.2002.00047.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Data from several studies support the hypothesis that thrombopoietin (TPO) plasma levels are regulated via circulating platelet (PLT) numbers by binding to PLT TPO receptors (TPO-Rs). In this study, PLT numbers and TPO plasma levels were measured following the transfusion of unmanipulated, sham-saturated, and TPO-R-saturated PLT preparations to provide additional in vivo evidence for this regulatory mechanism. STUDY DESIGN AND METHODS Following in vitro experiments to characterize pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) binding characteristics, PLT numbers and TPO plasma levels were measured following the transfusion of unmanipulated, sham-saturated, and TPO-R-saturated PLT preparations in thrombocytopenic patients. Sham-saturated and TPO-R-saturated PLTs were prepared by a 1-hour incubation without and with 40 ng per mL of PEG-rHuMGDF, respectively, and subsequent washing and resuspension. RESULTS In vitro, 2.72 +/- 0.8 ng of PEG-rHuMGDF per 1 x 10(8) PLTs was bound within 1 hour of incubation. No additional PEG-rHuMGDF was bound following a second incubation with PEG-rHuMGDF, and bound PEG-rHuMGDF was not released over time. In vivo, TPO plasma levels decreased significantly (p < 0.001), by 30.7 +/- 5.8 and 20.9 +/- 2.1 percent after transfusion of unmanipulated and sham-saturated PLT preparations, respectively. However, TPO plasma levels were unaffected after the transfusion of TPO-R-saturated PLTs despite comparable transfusion-induced PLT count increases. CONCLUSION These data strongly support the concept that binding to PLT TPO-R is directly involved in human TPO plasma level regulation in vivo.
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Affiliation(s)
- Stefan Scheding
- Department of Internal Medicine, University of Tübingen, Germany.
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17
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Abstract
The recent discovery of thrombopoietin has enhanced our understanding of both hematopoiesis and platelet production. Thrombopoietin supports hematopoietic stem cell survival and expansion as well as promoting all aspects of megakaryocyte development. The hormone displays many structural similarities to other members of the hematopoietic cytokine family and some notable differences, and regulation of its expression requires both receptor-mediated removal and other mechanisms. Thrombopoietin induces receptor dimerization and tyrosine phosphorylation, and a series of signaling events including activation of JAK/STAT, Shc/Ras/MAPK and PI3K/Akt; these pathways overlap with those induced by other cytokines, but the differences that lead to the unique biological effects of the hormone are gradually being uncovered. Our growing appreciation of how cytokine signaling pathways are translated into megakaryocyte development is discussed.
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Affiliation(s)
- Amy E Geddis
- Division of Hematology, University of Washington School of Medicine, Box 357710, 1959 NE Pacific Street, Seattle, WA 98195, USA
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18
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Folman CC, de Jong CM, de Haas M, von dem Borne AE. In multiple myeloma increased thrombopoietin (Tpo) production may be involved in the maintenance of platelet production. Eur J Haematol 2001; 66:337-41. [PMID: 11422414 DOI: 10.1034/j.1600-0609.2001.066005337.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In multiple myeloma (MM), suppression of haematopoiesis occurs as a result of expansion of malignant cells in the bone marrow. Thrombopoietin (Tpo) levels in patients with impaired platelet production are generally found to be highly elevated. To examine the circulating Tpo levels in patients with MM, Tpo levels were measured in 50 serum samples from 34 patients. Tpo levels were subsequently related to disease stage, and cell numbers and markers, i.e. platelet count, leukocyte count and haemoglobin (Hb) concentration. Elevated Tpo levels were found in association with decreased platelet counts (n=8), but also in patients with normal platelet counts (n=14). The latter group included patients without and with signs of impaired haematopoiesis, i.e. with decreased Hb concentration and decreased leukocyte count. These results show that neither platelet counts nor Tpo levels are reliable parameters to judge bone-marrow failure in patients with MM. Furthermore, in patients with MM, increased Tpo levels may play a role in the maintenance of thrombocytopoiesis. The origin of the increased Tpo levels remains to be determined.
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Affiliation(s)
- C C Folman
- Division of Internal Medicine and Department of Haematology, Academic Medical Centre, Amsterdam, The Netherlands
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