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Tezuka Y, Onoda N, Morishima T, Sumitomo Y, Nishii K, Takizawa H, Kai M. Expansion effect of romiplostim on hematopoietic stem and progenitor cells versus thrombopoietin and eltrombopag. Int J Hematol 2024:10.1007/s12185-024-03853-6. [PMID: 39302624 DOI: 10.1007/s12185-024-03853-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 09/05/2024] [Accepted: 09/11/2024] [Indexed: 09/22/2024]
Abstract
Romiplostim, a thrombopoietin (TPO) receptor agonist, is a clinically approved drug that is clearly effective in reconstituting hematopoiesis in refractory aplastic anemia and idiopathic thrombocytopenic purpura. However, the mechanism underlying its biological effect is unknown, and its differences from other TPO receptor agonists remain unclear. Therefore, we determined the in vitro expansion effect of romiplostim on human CD34 + hematopoietic stem and progenitor cells (HSPCs) versus recombinant human TPO (rhTPO) and another clinically available drug, eltrombopag. We also performed single-cell RNA-seq to determine effects of romiplostim on CD34 + HSPCs at the molecular level. The maximum expansion effect of romiplostim on total CD34 + cells, CD34 + CD38 + progenitor cells, and CD34 + CD38 - immature cells was comparable to that of rhTPO, but higher than that of eltrombopag, particularly on CD34 + CD38 - immature cells. Single-cell RNA-seq analysis revealed that both romiplostim and eltrombopag induced signatures driven by rhTPO, but romiplostim induced molecular changes related to RHOA signaling in the most primitive HSPC subsets that were partially driven or not driven by eltrombopag. Additionally, romiplostim did not induce TFRC expression as was observed with eltrombopag. In conclusion, romiplostim expands and affects human HSPCs similar to rhTPO, but partially different from eltrombopag in terms of induction of gene expression.
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Affiliation(s)
- Yuta Tezuka
- Research Division, Research Unit, Biomedical Science Research Laboratories 2, Kyowa Kirin Co., Ltd, 3-6-6, Asahi-Machi, Machida-Shi, Tokyo, 194-8533, Japan.
| | - Naoki Onoda
- Research Division, Research Unit, Biomedical Science Research Laboratories 2, Kyowa Kirin Co., Ltd, 3-6-6, Asahi-Machi, Machida-Shi, Tokyo, 194-8533, Japan
- Research Core Function Laboratories, Research Unit, Research Division, Kyowa Kirin Co., Ltd, Tokyo, Japan
| | - Tatsuya Morishima
- Laboratory of Stem Cell Stress, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, Japan
- Laboratory of Hematopoietic Stem Cell Engineering, IRCMS, Kumamoto University, Kumamoto, Japan
| | - Yoshiki Sumitomo
- Research Division, Research Unit, Biomedical Science Research Laboratories 2, Kyowa Kirin Co., Ltd, 3-6-6, Asahi-Machi, Machida-Shi, Tokyo, 194-8533, Japan
| | - Keigo Nishii
- Research Division, Research Unit, Biomedical Science Research Laboratories 2, Kyowa Kirin Co., Ltd, 3-6-6, Asahi-Machi, Machida-Shi, Tokyo, 194-8533, Japan
| | - Hitoshi Takizawa
- Laboratory of Stem Cell Stress, International Research Center for Medical Sciences (IRCMS), Kumamoto University, Kumamoto, Japan
- Center for Metabolic Regulation of Healthy Aging (CMHA), Kumamoto University, Kumamoto, Japan
| | - Masayuki Kai
- Research Division, Research Unit, Biomedical Science Research Laboratories 2, Kyowa Kirin Co., Ltd, 3-6-6, Asahi-Machi, Machida-Shi, Tokyo, 194-8533, Japan
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Brooks MB, Brooks JC, Catalfamo J, Zhu Y, Goggs R, Babasyan S, Wagner B, LeVine DN. Plasma concentration of thrombopoietin in dogs with immune thrombocytopenia. J Vet Intern Med 2024; 38:2507-2517. [PMID: 39143652 PMCID: PMC11423463 DOI: 10.1111/jvim.17152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 07/16/2024] [Indexed: 08/16/2024] Open
Abstract
BACKGROUND Immune thrombocytopenia (ITP) is a common cause of severe thrombocytopenia in dogs. The pathogenesis of nonassociative, primary ITP (pITP) appears complex, with ill-defined thrombopoietic response. OBJECTIVES Develop an immunoassay to measure plasma canine thrombopoietin (TPO) concentration and characterize TPO concentrations in dogs with pITP. ANIMALS Forty-one healthy dogs, 8 dogs in an induced ITP model (3 control, 5 ITP), and 58 pITP dogs. METHODS Recombinant canine TPO (rcTPO) was purchased and its identity confirmed by mass spectrometry. Monoclonal antibodies were raised to rcTPO and used to configure a sandwich ELISA using streptavidin-biotin detection. Assay performance, coefficients of variability, and healthy dog plasma TPO reference interval (RI) were determined, followed by assay of ITP samples. RESULTS Assay dynamic range was 15 pg/mL (lower limit of detection) to 1000 pg/mL TPO, with limit of quantitation of 62 pg/mL. Plasma TPO RI was 0 to 158 pg/mL, with plasma TPO <62 pg/mL for 35/41 healthy dogs. All dogs with induced ITP developed marked increases in plasma TPO concentration. Peak values ranged from 515 to >6000 pg/mL. In contrast, only 2/58 pITP dogs had TPO values above RI. CONCLUSIONS AND CLINICAL IMPORTANCE Plasma TPO concentration is paradoxically low at diagnosis for most dogs with pITP. This finding suggests that ineffective thrombopoiesis contributes to thrombocytopenia in pITP dogs and supports evaluating TPO receptor agonist treatment as used for pITP in humans. The TPO assay provides a new tool to study thrombopoiesis in pITP and other thrombocytopenic syndromes in dogs.
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Affiliation(s)
- Marjory B. Brooks
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - James C. Brooks
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - Jim Catalfamo
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - Yao Zhu
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - Robert Goggs
- Department of Clinical Sciences, College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - Susanna Babasyan
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - Bettina Wagner
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - Dana N. LeVine
- Department of Veterinary Clinical Sciences, College of Veterinary MedicineAuburn UniversityAuburnAlabamaUSA
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Chen H, Ma J, Ouyang J, Fu L, Ma J, Yao J, Wu R, Chen Z. The Differences of Serum Thrombopoietin Levels Between Acquired Aplastic Anemia and Immune Thrombocytopenia in Pediatric Patients. J Pediatr Hematol Oncol 2024; 46:281-286. [PMID: 38857156 DOI: 10.1097/mph.0000000000002873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 04/02/2024] [Indexed: 06/12/2024]
Abstract
Thrombopoietin (TPO) is the critical regulator of platelet production. However, the role of TPO in pediatric patients with thrombocytopenic disorders has not been fully elucidated. In the present study, we attempted to investigate serum TPO levels in patients with acquired aplastic anemia (aAA) and immune thrombocytopenia (ITP). We analyzed the endogenous plasma concentration of TPO and platelet count at the time of TPO measurement in 166 patients with aAA and 280 patients with ITP retrospectively. We further observed a correlation between platelet counts and TPO. Serum TPO levels were significantly higher in aAA compared with ITP (1142 vs. 77.99 pg/mL, P <0.001). In patients with aAA, an elevation for TPO levels in very severe AA (VSAA) was seen when compared with non-severe AA (NSAA) (1360 vs. 984.4 pg/mL, P <0.05). In contrast, the circulating TPO levels with chronic ITP (CITP) showed a decrease than newly diagnosed ITP (NITP) and persistent ITP (PITP) (62.28 vs. 81.56 pg/mL, P <0.01, 62.28 vs. 87.82 pg/mL, P <0.05, respectively). There was a negative correlation between platelet counts and TPO levels in aAA (r s =-0.3325, P <0.001) as well as ITP (r s =-0.2570, P <0.001). Especially, TPO levels were inversely correlated with platelet counts in NSAA (r s =-0.3672, P <0.001) and NITP (r s =-0.3316, P <0.001). After grouping by age or sex, there were no statistical differences in aAA or ITP. Serum TPO levels were markedly elevated in pediatric patients with aAA compared with ITP. It was higher in VSAA and lower in CITP, suggesting that serum TPO level could play a role in classifying disease severity or clinical course in aAA and ITP.
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Affiliation(s)
- Hui Chen
- Hematologic Disease Laboratory, Hematology Center
| | - Jie Ma
- Hematology Center, Beijing Key Laboratory of Pediatric Hematology Oncology; National Key Discipline of Pediatrics (Capital Medical University); Key Laboratory of Major Diseases in Children, Ministry of Education; Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, China
| | | | - Lingling Fu
- Hematology Center, Beijing Key Laboratory of Pediatric Hematology Oncology; National Key Discipline of Pediatrics (Capital Medical University); Key Laboratory of Major Diseases in Children, Ministry of Education; Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, China
| | - Jingyao Ma
- Hematology Center, Beijing Key Laboratory of Pediatric Hematology Oncology; National Key Discipline of Pediatrics (Capital Medical University); Key Laboratory of Major Diseases in Children, Ministry of Education; Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, China
| | - Jiafeng Yao
- Hematology Center, Beijing Key Laboratory of Pediatric Hematology Oncology; National Key Discipline of Pediatrics (Capital Medical University); Key Laboratory of Major Diseases in Children, Ministry of Education; Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, China
| | - Runhui Wu
- Hematology Center, Beijing Key Laboratory of Pediatric Hematology Oncology; National Key Discipline of Pediatrics (Capital Medical University); Key Laboratory of Major Diseases in Children, Ministry of Education; Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, China
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Karakas D, Xu M, Ni H. GPIbα is the driving force of hepatic thrombopoietin generation. Res Pract Thromb Haemost 2021; 5:e12506. [PMID: 33977209 PMCID: PMC8105161 DOI: 10.1002/rth2.12506] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/19/2021] [Accepted: 02/26/2021] [Indexed: 12/25/2022] Open
Abstract
Thrombopoietin (TPO), a glycoprotein hormone produced predominantly in the liver, plays important roles in the hematopoietic stem cell (HSC) niche, and is essential for megakaryopoiesis and platelet generation. Long-standing understanding proposes that TPO is constitutively produced by hepatocytes, and levels are fine-tuned through platelet and megakaryocyte internalization/degradation via the c-Mpl receptor. However, in immune thrombocytopenia (ITP) and several other diseases, TPO levels are inconsistent with this theory. Recent studies showed that platelets, besides their TPO clearance, can induce TPO production in the liver. Our group also accidentally discovered that platelet glycoprotein (GP) Ibα is required for platelet-mediated TPO generation, which is underscored in both GPIbα-/- mice and patients with Bernard-Soulier syndrome. This review will introduce platelet versatilities and several new findings in hemostasis and platelet consumption but focus on its roles in TPO regulation. The implications of these new discoveries in hematopoiesis and the HSC niche, particularly in ITP, will be discussed.
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Affiliation(s)
- Danielle Karakas
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
- Toronto Platelet Immunobiology GroupTorontoONCanada
- Department of Laboratory MedicineKeenan Research Centre for Biomedical ScienceSt. Michael’s HospitalTorontoONCanada
| | - Miao Xu
- Department of HematologyQilu HospitalCheeloo College of MedicineShandong UniversityJinanChina
| | - Heyu Ni
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
- Toronto Platelet Immunobiology GroupTorontoONCanada
- Department of Laboratory MedicineKeenan Research Centre for Biomedical ScienceSt. Michael’s HospitalTorontoONCanada
- Canadian Blood Services Centre for InnovationTorontoONCanada
- Department of MedicineUniversity of TorontoTorontoONCanada
- Department of PhysiologyUniversity of TorontoTorontoONCanada
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5
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Zaimoku Y, Patel BA, Shalhoub R, Groarke EM, Feng X, Wu CO, Young NS. Predicting response of severe aplastic anemia to immunosuppression combined with eltrombopag. Haematologica 2021; 107:126-133. [PMID: 33910334 PMCID: PMC8719075 DOI: 10.3324/haematol.2021.278413] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Indexed: 11/20/2022] Open
Abstract
Pretreatment blood counts, particularly an absolute reticulocyte count ≥25×109/L, correlate with response to immunosuppressive therapy in severe aplastic anemia. In recent trials, eltrombopag combined with standard immunosuppressive therapy yielded superior responses than those to immunosuppressive therapy alone. Our single institution retrospective study aimed to elucidate whether historical predictors of response to immunosuppressive therapy alone were also associated with response to immunosuppressive therapy plus eltrombopag. We sought correlations of blood counts, thrombopoietin levels and the presence of paroxysmal nocturnal hemoglobinuria clones with both overall and complete responses in 416 patients with severe aplastic anemia, aged 2-82 years (median, 30 years), initially treated with immunosuppressive therapy plus eltrombopag between 2012 and 2019 (n=176) or with immunosuppressive therapy alone between 1999 and 2010 (n=240). Compared to non-responders, patients in the group of overall responders to immunosuppressive therapy plus eltrombopag had significantly higher pretreatment absolute reticulocyte counts, higher neutrophil counts and reduced thrombopoietin levels, as also observed for the group treated with immunosuppressive therapy alone. Addition of eltrombopag markedly improved the overall response in subjects with an absolute reticulocyte count between 10-30×109/L from 60% (54 of 90) to 91% (62 of 68). Absolute lymphocyte count correlated with complete response in the groups treated with immunosuppressive therapy with or without eltrombopag, especially in adolescents aged ≥10 years and adults, but the correlation was reversed in younger children. Platelet count and the presence of a paroxysmal nocturnal hemoglobinuria clone did not correlate with responses to immunosuppressive therapy. Blood counts remain the best predictors of response to nontransplant therapies in severe aplastic anemia. Addition of eltrombopag to immunosuppressive therapy shifted patients with a lower absolute reticulocyte count into a better prognostic category.
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Affiliation(s)
- Yoshitaka Zaimoku
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health.
| | - Bhavisha A Patel
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health
| | - Ruba Shalhoub
- Office of Biostatistics Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Emma M Groarke
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health
| | - Xingmin Feng
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health
| | - Colin O Wu
- Office of Biostatistics Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Neal S Young
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health
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6
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Mahat U, Rotz SJ, Hanna R. Use of Thrombopoietin Receptor Agonists in Prolonged Thrombocytopenia after Hematopoietic Stem Cell Transplantation. Biol Blood Marrow Transplant 2020; 26:e65-e73. [DOI: 10.1016/j.bbmt.2019.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 01/09/2023]
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7
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Hans R, Sharma RR, Marwaha N. Effect of plateletpheresis on postdonation serum thrombopoietin levels and its correlation with platelet counts in healthy voluntary donors. Asian J Transfus Sci 2019; 13:10-16. [PMID: 31360004 PMCID: PMC6580838 DOI: 10.4103/ajts.ajts_86_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND: Thrombopoietin (TPO) is regulated by a feedback mechanism between megakaryocytes and platelets. This is important in plateletpheresis donors to compensate for donation-associated platelet loss. AIMS AND OBJECTIVES: The aim and objective of this study were to investigate changes in serum TPO levels in healthy plateletpheresis donors and its correlation with platelet recovery pattern. MATERIALS AND METHODS: Out of 50 plateletpheresis donors recruited in the study over 1 year, only 29 completed follow-up and were further analyzed. Plateletpheresis procedures were performed on two types of cell separators (TRIMA ACCEL®, Terumo BCT Lakewood Colorado and AMICUS®, Fresenius Kabi, Germany). Platelet parameters were estimated pre- and post-platelet donation, at 3rd- and 5th-day postdonation. Serum TPO levels were determined using quantitative sandwich enzyme-linked immunosorbent assay technique (Raybiotech, USA) as per the protocol of the manufacturer. RESULTS: The majority of donors (72%) in our study were first-time donors. The baseline platelet count was 226 ± 44 × 103/μl with a significant decline (30%; P < 0.001) in postdonation phase and remained below baseline on the 3rd and 5th day. The serum TPO levels increased significantly (P < 0.001) from a baseline of 227.81 (interquartile range [IQR]: 176.06) pg/ml to 269.94 (IQR: 110.68) pg/ml postdonation and remained elevated from baseline levels on the 3rd and 5th day. An inverse relation was observed between change in serum TPO levels and platelet count during postdonation phase which was not statistically significant (P > 0.05). CONCLUSION: Serum TPO levels increase significantly post plateletpheresis donation corresponding to decrease in platelet counts showing that TPO plays a vital role in compensatory mechanism after platelet loss.
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Affiliation(s)
- Rekha Hans
- Department of Transfusion Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Ratti Ram Sharma
- Department of Transfusion Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Neelam Marwaha
- Department of Transfusion Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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Akram Z, Ahmed P, Kajigaya S, Satti TM, Satti HS, Chaudhary QUN, Gutierrez-Rodrigues F, Ibanez PF, Feng X, Mahmood SK, Ghafoor T, Shahbaz N, Khan MA, Sultan A. Epidemiological, clinical and genetic characterization of aplastic anemia patients in Pakistan. Ann Hematol 2018; 98:301-312. [PMID: 30426156 DOI: 10.1007/s00277-018-3542-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 11/05/2018] [Indexed: 11/29/2022]
Abstract
Aplastic anemia (AA) is the most serious non-malignant blood disorder in Pakistan, ranked second in prevalence, after thalassemia. We investigated various epidemiological, clinical, and genetic factors of AA in a Pakistani cohort of 214 patients reporting at our hospital between June 2014 and December 2015. A control group of 214 healthy subjects was included for comparison of epidemiological and clinical features. Epidemiological data revealed 2.75-fold higher frequency of AA among males. A single peak of disease onset was observed between ages 10 and 29 years followed by a steady decline. AA was strongly associated with lower socioeconomic profile, rural residence, and high rate of consanguineous marriages. Serum granulocyte colony-stimulating factor and thrombopoietin levels were significantly elevated in AA patients, compared to healthy controls (P < 0.0001), while there was no statistical significance in other nine cytokine levels screened. Allele frequencies of DRB1*15 (56.8%) and DQB1*06 (70.3%) were predominantly high in AA patients. Ten mutations were found in TERT and TERC genes, including two novel mutations (Val526Ala and Val777Met) in exons 3 and 7 of TERT gene. Despite specific features of the AA cohort, this study suggests that epidemiologic and etiologic factors as well as host genetic predisposition exclusively or cooperatively trigger AA in Pakistan.
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Affiliation(s)
- Zaineb Akram
- Cell Biology Section, Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10-CRC, Room 3E-5140, 10 Center Drive, Bethesda, MD, 20892, USA. .,Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan. .,Department of Biochemistry, Quaid-i-Azam University, Islamabad, 44000, Pakistan.
| | - Parvez Ahmed
- Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan
| | - Sachiko Kajigaya
- Cell Biology Section, Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10-CRC, Room 3E-5140, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Tariq Mahmood Satti
- Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan
| | - Humayoon Shafique Satti
- Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan
| | - Qamar Un Nisa Chaudhary
- Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan
| | - Fernanda Gutierrez-Rodrigues
- Cell Biology Section, Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10-CRC, Room 3E-5140, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Pilar F Ibanez
- Cell Biology Section, Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10-CRC, Room 3E-5140, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Xingmin Feng
- Cell Biology Section, Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10-CRC, Room 3E-5140, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Syed Kamran Mahmood
- Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan
| | - Tariq Ghafoor
- Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan
| | - Nighat Shahbaz
- Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan
| | - Mehreen Ali Khan
- Armed Forces Bone Marrow Transplant Centre (AFBMTC), Combined Military Hospital, Rawalpindi, 46000, Pakistan
| | - Aneesa Sultan
- Department of Biochemistry, Quaid-i-Azam University, Islamabad, 44000, Pakistan
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9
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Affiliation(s)
- Neal S Young
- From the Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, MD
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10
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Schoettler ML, Nathan DG. The Pathophysiology of Acquired Aplastic Anemia: Current Concepts Revisited. Hematol Oncol Clin North Am 2018; 32:581-594. [PMID: 30047412 PMCID: PMC6538304 DOI: 10.1016/j.hoc.2018.03.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Idiopathic acquired aplastic anemia is a rare, life-threatening bone marrow failure syndrome characterized by cytopenias and hypocellular bone marrow. The pathophysiology is unknown; the most favored model is of a dysregulated immune system leading to autoreactive T-cell destruction of hematopoietic stem and progenitor cells in a genetically susceptible host. The authors review the literature and propose that the major driver of acquired aplastic anemia is a combination of hematopoietic stem and progenitor cells intrinsic defects and an inappropriately activated immune response in the setting of a viral infection. Alterations in bone marrow microenvironment may also contribute to the disease process.
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Affiliation(s)
- Michelle L Schoettler
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215-5450, USA; Division of Hematology/Oncology, Boston Children's Hospital, 450 Brookline Avenue, Boston, MA 02215, USA; Department of Pediatrics, Harvard Medical School, 450 Brookline Avenue, Boston, MA 02215, USA
| | - David G Nathan
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215-5450, USA; Division of Hematology/Oncology, Boston Children's Hospital, 450 Brookline Avenue, Boston, MA 02215, USA; Department of Pediatrics, Harvard Medical School, 450 Brookline Avenue, Boston, MA 02215, USA.
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11
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Zhao X, Feng X, Wu Z, Winkler T, Desmond R, Olnes M, Dumitriu B, Townsley DM, Dunbar CE, Young NS. Persistent elevation of plasma thrombopoietin levels after treatment in severe aplastic anemia. Exp Hematol 2017; 58:39-43. [PMID: 28941711 DOI: 10.1016/j.exphem.2017.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 11/29/2022]
Abstract
Although hematopoietic growth factors are found at high levels in aplastic anemia (AA) patients, little is known about their dynamic change over time after treatment. We examined plasma concentrations of hematopoietic growth factors sequentially in 55 severe AA patients, including 45 treatment-naive patients who had received immunosuppressive therapy (IST) or IST and eltrombopag, and 10 IST-refractory patients who had received eltrombopag only, focusing on thrombopoietin (TPO). TPO concentrations were much higher than normal in patients before treatment and then decreased in responders but not in nonresponders. We followed up on a cohort of nine patients who obtained stable complete remission for up to 7 years after IST and found that TPO levels declined gradually by 3 months after treatment, accompanying an increase in platelet counts, but stabilized at levels higher than normal. An inverse correlation was noted between TPO levels and platelet counts. The increased plasma TPO levels could be required to maintain normal platelet counts in remission and could also be attributed to reduced consumption by circulating platelets.
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Affiliation(s)
- Xin Zhao
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Xingmin Feng
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD.
| | - Zhijie Wu
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Thomas Winkler
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Ronan Desmond
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Matthew Olnes
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Bogdan Dumitriu
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Danielle M Townsley
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Cynthia E Dunbar
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Neal S Young
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
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12
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Platelet clearance by the hepatic Ashwell-Morrell receptor: mechanisms and biological significance. Thromb Res 2017; 141 Suppl 2:S68-72. [PMID: 27207430 DOI: 10.1016/s0049-3848(16)30370-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The daily production of billions of platelets must be regulated to avoid spontaneous bleeding or arterial occlusion and organ damage. Complex mechanisms control platelet production and clearance in physiological and pathological conditions. This review will focus on the mechanisms of platelet senescence with specific emphasis on the role of post-translational modifications in platelet life-span and thrombopoietin production downstream of the hepatic Ashwell-Morrell receptor.
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13
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Gill H, Wong RSM, Kwong YL. From chronic immune thrombocytopenia to severe aplastic anemia: recent insights into the evolution of eltrombopag. Ther Adv Hematol 2017; 8:159-174. [PMID: 28473904 DOI: 10.1177/2040620717693573] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Thrombopoietin (TPO) is the most potent cytokine stimulating thrombopoiesis. Therapy with exogenous TPO is limited by the formation of antibodies cross-reacting with endogenous TPO. Mimetics of TPO are compounds with no antigenic similarity to TPO. Eltrombopag is an orally-active nonpeptide small molecule that binds to the transmembrane portion of the TPO receptor MPL. Initial trials of eltrombopag have centered on immune thrombocytopenia (ITP), which is due to both increased destruction and decreased production of platelets. Eltrombopag at 25-75 mg/day has been shown to be highly effective in raising the platelet count in ITP with suboptimal response to immunosuppression and splenectomy. These successful results led to the exploration of eltrombopag in other thrombocytopenic disorders. In hepatitis C viral infection, eltrombopag raises the platelet count sufficiently enough to allow treatment with ribavirin and pegylated interferon. Because MPL is expressed on hematopoietic cells, eltrombopag use in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) might enhance leukemic proliferation. Clinical trials of eltrombopag in MDS and AML, however, have shown amelioration of thrombocytopenia without promoting disease progression. In severe aplastic anemia (SAA) not responding to immunosuppression with anti-thymocyte globulin (ATG) and cyclosporine, eltrombopag as a single agent at 150-300 mg/day results in an overall response rate of 40-70%. At high doses, adverse effects including pigmentation, gastrointestinal upset and hepatic derangement have become evident. Current studies have examined the first-line use of eltrombopag in combination with ATG in SAA. In a recent study, eltrombopag used at 150 mg/day with horse ATG resulted in an overall response rate of 90% in newly diagnosed SAA patients, with a complete response rate of about 50%. Clonal karyotypic aberrations are, however, found in 10-20% of SAA patients treated with eltrombopag. The safety and efficacy of eltrombopag in SAA require further evaluation, particularly when it is used with less intensive immunosuppression.
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Affiliation(s)
- Harinder Gill
- Department of Medicine, Queen Mary Hospital, Hong Kong, China
| | - Raymond S M Wong
- Sir Y.K. Pao Centre for Cancer and Department of Medicine and Therapeutics, Prince of Wales Hospital, the Chinese University of Hong Kong, Hong Kong, China
| | - Yok-Lam Kwong
- Department of Medicine, Queen Mary Hospital, Pokfulam Road, Hong Kong, China
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14
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Zhang J, Wu Q, Zheng Y. Persistent elevated bone marrow plasma levels of thrombopoietin in patients with aplastic anemia. Cytokine 2016; 85:11-3. [PMID: 27269179 DOI: 10.1016/j.cyto.2016.05.020] [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] [Received: 01/15/2016] [Revised: 05/21/2016] [Accepted: 05/24/2016] [Indexed: 11/24/2022]
Abstract
Acquired aplastic anemia (AA) is an immune-mediated bone marrow (BM) failure syndrome. Plasma thrombopoietin (TPO) levels are elevated in AA patients with reduced blood counts. However, whether elevated TPO can recover to normal level in AA patients in complete remission (CR) after efficient immunosuppressive therapy (IST) is unknown. We measured TPO levels of BM plasma in a large cohort of AA patients with focusing on patients in CR after IST. Our data showed that BM plasma TPO levels were still high in patients who had reached normal blood counts levels for a long time. We speculate that downregulated expression of MPL (TPO receptor) in HSPC (hematopoietic stem and progenitor cells) may be related to the upregulated TPO in AA.
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Affiliation(s)
- Jizhou Zhang
- Severe Aplastic Anemia Studying Program, Institute of Hematology & Blood Diseases Hospital, State Key Laboratory of Experimental Hematology, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, PR China
| | - Qingqing Wu
- Severe Aplastic Anemia Studying Program, Institute of Hematology & Blood Diseases Hospital, State Key Laboratory of Experimental Hematology, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, PR China
| | - Yizhou Zheng
- Severe Aplastic Anemia Studying Program, Institute of Hematology & Blood Diseases Hospital, State Key Laboratory of Experimental Hematology, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, PR China.
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15
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Elmahdi S, Muramatsu H, Narita A, Ismael O, Hama A, Nishio N, Okuno Y, Xu Y, Wang X, Takahashi Y, Kojima S. Markedly High Plasma Thrombopoietin (TPO) Level is a Predictor of Poor Response to Immunosuppressive Therapy in Children With Acquired Severe Aplastic Anemia. Pediatr Blood Cancer 2016; 63:659-64. [PMID: 26575027 DOI: 10.1002/pbc.25820] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 09/30/2015] [Accepted: 10/05/2015] [Indexed: 01/31/2023]
Abstract
BACKGROUND Immunosuppressive therapy (IST) is commonly used for patients with acquired severe aplastic anemia (SAA). Because the clinical response rate and therapeutic outcome for individual patients to IST varies, an in vitro test that identifies potential responders would be desirable. METHODS We evaluated the relationship between thrombopoietin (TPO) levels at the time of diagnosis and the response to IST at 6 months in 85 children (median age, 9.0 years; range, 1.0-15.5 years) with acquired SAA using enzyme-linked immunosorbent assay. Thirty-one age-matched healthy individuals were used as controls. All patients received antithymocyte globulin and cyclosporine. RESULTS Overall, 39 patients (45.9%) responded to IST at 6 months. TPO plasma levels were significantly higher in nonresponders than in responders (1,555.8 vs. 1,284.7 pg/ml, respectively; P = 0.031). Multivariate analysis identified the TPO levels of >1,796.7 pg/ml (TPO-high group, 20 patients; odds ratio (OR), 8.285; 95% confidence interval (CI), 2.114-32.904; P = 0.002) as independent poor predictors of IST response at 6 months. Moreover, the TPO-high group was associated with lower 5-year failure-free survival rates (30% vs. 68%, P = 0.012) compared with the TPO-low group. CONCLUSION The measurement of TPO levels at diagnosis is useful for predicting the response to IST in children with SAA and may help in decision making.
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Affiliation(s)
- Shaimaa Elmahdi
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hideki Muramatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Narita
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Olfat Ismael
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Asahito Hama
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobuhiru Nishio
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yusuke Okuno
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yinyan Xu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Xinan Wang
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshiyuki Takahashi
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Seiji Kojima
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
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16
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Regulating billions of blood platelets: glycans and beyond. Blood 2015; 126:1877-84. [PMID: 26330242 DOI: 10.1182/blood-2015-01-569129] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 08/25/2015] [Indexed: 01/01/2023] Open
Abstract
The human body produces and removes 10(11) platelets daily to maintain a normal steady state platelet count. Platelet production must be regulated to avoid spontaneous bleeding or arterial occlusion and organ damage. Multifaceted and complex mechanisms control platelet production and removal in physiological and pathological conditions. This review will focus on different mechanisms of platelet senescence and clearance with specific emphasis on the role of posttranslational modifications. It will also briefly address platelet transfusion and the role of glycans in the clearance of stored platelets.
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17
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Singh A, Verma A, Nityanand S, Chaudhary R, Elhence P. Circulating thrombopoietin levels in normal healthy blood donors and in aplastic anemia patients in relation to disease severity. Asian J Transfus Sci 2015; 9:70-3. [PMID: 25722577 PMCID: PMC4339937 DOI: 10.4103/0973-6247.150956] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Thrombopoietin (TPO) is the key hematopoietic growth factor regulating the production of platelets from bone marrow megakaryocytes and maintaining platelet hemostasis. This study was done to find any relationship between the levels of thrombopoietin and the severity of disease in patients with aplastic anemia. Materials and Methods: Serum samples were collected from 52 patients with a confirmed diagnosis of aplastic anemia and 45 normal healthy blood donors of both sexes over a period of 2 years, and TPO was estimated by using commercially available TPO-specific-enzyme-linked immunosorbent assay. Results: The median TPO level of 1190 pg/ml (range 625-7651 pg/ml) in aplastic anemia patients was significantly higher than the median TPO level of 121.1 pg/ml (81.25-237.7 pg/ml) in normal healthy blood donors (P = 0.000). No significant difference was observed in TPO levels of male and female patients (P = 0.453). The median TPO concentrations observed in very severe aplastic anemia, severe aplastic anemia, and nonsevere aplastic anemia were 2765 pg/ml (range 625-6451 pg/ml), 1190 pg/ml (range 672.1-7651 pg/ml), and 1111.5 pg/ml (range 761.1-2289.2 pg/ml), respectively. TPO in patients of very severe aplastic anemia was significantly higher than patients of nonsevere aplastic anemia (P = 0.043), with no significant relation among rest of the groups. Discussion: TPO levels in aplastic anemia patients were significantly higher than in healthy blood donors; however, in aplastic anemia patients TPO levels were significantly higher only in patients with very severe disease.
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Affiliation(s)
- Abhay Singh
- Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
| | - Anupam Verma
- Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
| | - Soniya Nityanand
- Department of Hematology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
| | - Rajendra Chaudhary
- Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
| | - Priti Elhence
- Department of Transfusion Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
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18
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Rank A, Weigert O, Ostermann H. Management of chronic immune thrombocytopenic purpura: targeting insufficient megakaryopoiesis as a novel therapeutic principle. Biologics 2010; 4:139-45. [PMID: 20531970 PMCID: PMC2880346 DOI: 10.2147/btt.s3436] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Indexed: 12/20/2022]
Abstract
Traditionally, anti-platelet autoantibodies accelerating platelet clearance from the peripheral circulation have been recognized as the primary pathopysiological mechanism in chronic immune thrombocytopenia (ITP). Recently, increasing evidence supports the co-existence of insufficient megakaryopoiesis. Inadequate low thrombopoietin (TPO) levels are associated with insufficient proliferation and differentiation of megakaryocytes, decreased proplatelet formation, and subsequent platelet release. Recently two novel activators of TPO receptors have been made available: romiplostim and eltrombopag. In several phase III studies, both agents demonstrated increase of platelet counts in about 80% of chronic ITP patients within 2 to 3 weeks. These agents substantially broaden the therapeutic options for patients with chronic ITP although long-term results are still pending. This review will provide an update on the current conception of underlying mechanisms in ITP and novel, pathophysiologically based treatment options.
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Affiliation(s)
- Andreas Rank
- Medizinische Klinik III - Grosshadern, Klinikum der Ludwig Maximilians-Universitaet Munich, Munich, Germany
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19
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Li JP, Zheng CL, Han ZC. Abnormal immunity and stem/progenitor cells in acquired aplastic anemia. Crit Rev Oncol Hematol 2009; 75:79-93. [PMID: 20045349 DOI: 10.1016/j.critrevonc.2009.12.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 11/28/2009] [Accepted: 12/09/2009] [Indexed: 10/20/2022] Open
Abstract
Acquired aplastic anemia (AA) is considered as an immune-mediated bone marrow failure syndrome, characterized by hypoplasia and pancytopenia with fatty bone marrow. Abnormal immunity is the major factor mediating the pathogenesis of acquired AA. Activated DCs might promote the polarization to Th1 cells, and activate CD8(+) T cells. A variety of immune molecules including IFN-gamma, TNF-alpha, MIP-1alpha and IL-2, 8, 12, 15, 17, 23, produced by them and stromal cells, compose a cytokine network to destruct stem/progenitor cells as well as hematopoietic stem/progenitor cells, mesenchymal stem cells (MSCs) and angioblasts/endothelial progenitor cells. Inversely, deficient MSCs, CD4(+)CD25(+) T cells, NK cells, NKT cells and early hematopoietic growth factors diminish the capacity of immune regulation and the support of hematopoiesis. As a result, stem/progenitor cells are significantly impaired to be disabled cells with markedly deficient proliferation, differentiation, induced apoptosis and dysfunctional response to growth factor stimuli, together with rare normal ones. Although some patients can be ameliorated by stem-cell transplantation or immunosuppressive therapy, more effective and convenient therapies such as patient-specific pluripotent iPS cells based on definite pathogenesis are expected.
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Affiliation(s)
- Jian Ping Li
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, 288 Nanjing Road, Tianjin 300020, PR China
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20
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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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21
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Yamazaki R, Kuwana M, Mori T, Okazaki Y, Kawakami Y, Ikeda Y, Okamoto S. Prolonged thrombocytopenia after allogeneic hematopoietic stem cell transplantation: associations with impaired platelet production and increased platelet turnover. Bone Marrow Transplant 2006; 38:377-84. [PMID: 16915226 DOI: 10.1038/sj.bmt.1705444] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To evaluate the mechanisms underlying prolonged thrombocytopenia after allogeneic hematopoietic stem cell transplantation (SCT), an index for plasma glycocalicin normalized for the individual platelet count (GCI), plasma thrombopoietin (TPO), and circulating B cells producing anti-GPIIb-IIIa antibodies were measured in 50 SCT recipients with or without prolonged thrombocytopenia, 42 patients with idiopathic thrombocytopenic purpura, nine patients with aplastic anemia, and 22 healthy individuals. All three indices were significantly higher in the SCT recipients with thrombocytopenia than in those without (P < 0.01 for all comparisons), and were significantly correlated with the platelet count in SCT recipients. Stepwise multiple regression analysis of the samples from the SCT recipients revealed that GCI and TPO independently pointed to specific mechanisms of thrombocytopenia. The GCI and TPO status in SCT recipients with thrombocytopenia had a pattern similar to that seen in aplastic anemia, suggesting a major role for impaired thrombopoiesis. An antiplatelet antibody response was frequently detected in SCT recipients, but the development of thrombocytopenia is likely to depend on additional factors, such as reticuloendothelial function. In summary, post transplant prolonged thrombocytopenia is associated with complex mechanisms, including impaired thrombopoiesis and increased platelet turnover.
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Affiliation(s)
- R Yamazaki
- Division of Hematology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
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22
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Kuwana M, Okazaki Y, Kajihara M, Kaburaki J, Miyazaki H, Kawakami Y, Ikeda Y. Autoantibody to c-Mpl (thrombopoietin receptor) in systemic lupus erythematosus: relationship to thrombocytopenia with megakaryocytic hypoplasia. ARTHRITIS AND RHEUMATISM 2002; 46:2148-59. [PMID: 12209520 DOI: 10.1002/art.10420] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE To examine the prevalence, clinical associations, and pathogenic role of autoantibodies to c-Mpl, the thrombopoietin (TPO) receptor, in patients with systemic lupus erythematosus (SLE). METHODS Sera from 69 SLE patients, 84 patients with idiopathic thrombocytopenic purpura (ITP), and 60 healthy individuals were screened for anti-c-Mpl antibodies by enzyme-linked immunosorbent assay using recombinant c-Mpl as an antigen. Clinical findings, autoantibody profiles, and serum TPO levels were compared between SLE patients with and without anti-c-Mpl antibodies. A pathogenic role for the anti-c-Mpl antibody was evaluated by examining its inhibitory effect on TPO-dependent cell proliferation and megakaryocyte colony formation. RESULTS Serum anti-c-Mpl antibody was detected in 8 SLE patients (11.6%) and 7 ITP patients (8.3%), but in none of the healthy controls. Anti-c-Mpl antibody was associated with thrombocytopenia (P = 0.0002) and a decrease in bone marrow megakaryocytes (P = 0.02) in SLE patients. Serum TPO levels in thrombocytopenic SLE patients with anti-c-Mpl antibodies were significantly elevated compared with levels in those without the antibodies (P = 0.007). IgG fractions purified from anti-c-Mpl antibody-positive sera bound to c-Mpl expressed on the cell surface and inhibited TPO-dependent cell proliferation and megakaryocyte colony formation. CONCLUSION Autoantibody to c-Mpl is present in a subset of SLE patients with thrombocytopenia and megakaryocytic hypoplasia. It is likely that the impaired thrombopoiesis in these patients is mediated by the anti-c-Mpl antibody, which functionally blocks an interaction between TPO and c-Mpl.
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MESH Headings
- Adolescent
- Adult
- Aged
- Animals
- Autoantibodies/immunology
- Bone Marrow Cells/pathology
- Cell Division/drug effects
- Colony-Forming Units Assay
- Dose-Response Relationship, Immunologic
- Enzyme-Linked Immunosorbent Assay
- Female
- Humans
- Lupus Erythematosus, Systemic/blood
- Lupus Erythematosus, Systemic/complications
- Lupus Erythematosus, Systemic/immunology
- Male
- Megakaryocytes/pathology
- Megakaryocytes/physiology
- Middle Aged
- Neoplasm Proteins
- Proto-Oncogene Proteins/blood
- Proto-Oncogene Proteins/immunology
- Proto-Oncogene Proteins/pharmacology
- Purpura, Thrombocytopenic, Idiopathic/etiology
- Purpura, Thrombocytopenic, Idiopathic/immunology
- Receptors, Cytokine
- Receptors, Thrombopoietin
- Recombinant Proteins/blood
- Recombinant Proteins/immunology
- Recombinant Proteins/pharmacology
- Transfection
- Tumor Cells, Cultured
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23
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Lin XY, Hanada S, Uozumi K, Utsunomiya A, Suzuki S, Shimotakahara S, Takeuchi S, Takatsuka Y, Arima T. Serum levels of endogenous thrombopoietin and granulocyte-colony stimulating factor in patients with acute or lymphoma type adult T-cell leukemia during multicycle chemotherapy. Leuk Lymphoma 2002; 43:343-9. [PMID: 11999567 DOI: 10.1080/10428190290006134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Recent multidrug chemotherapy for adult T-cell leukemia (ATL) showed improved findings, however, these protocols often induced persistent myelosuppression. Among 67 patients with acute and lymphoma type ATL treated between January 1996 and December 1998, 42 patients died during this period and showed chemotherapy-induced myelosuppression. To characterize the relation between the severity of myelosuppression and the endogenous thrombopoietin (TPO) or granulocyte-colony stimulating factor (G-CSF) levels in ATL patients, we measured these hematopoietic factors using ELISA method. Nineteen patients with acute or lymphoma type ATL and 16 healthy individuals were examined. During thrombocytopenia, the serum TPO levels were significantly higher than that of controls (P < 0.0001) and were inversely correlated with the platelet counts (r = -0.687 P < 0.001). Later in the chemotherapy cycle, severe persistent thrombocytopenia occurred and TPO levels elevated and remained at a high level approximating the TPO levels of exogenous TPO administration (0.3 microg/kg body weight). On the other hand, the serum G-CSF levels with absolute neutrophil counts (ANC) below 0.5 x 10(9)/L were significantly higher than controls (P = 0.009) and inversely correlated with ANC (r = -0.382 P = 0.0034). However, G-CSF levels in six samples obtained after 6 h of G-CSF (100-150 microg per body) administration was approximately 50-fold higher than that in the neutropenic states. These findings suggested that G-CSF can effectively reduce the severity and duration of intensified chemotherapy-induced neutropenia and higher dose exogenous TPO (higher than 0.6 microg/kg per day) therapy may be required to enhance platelet recovery after intensive chemotherapy in ATL patients.
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Affiliation(s)
- Xiao-Yan Lin
- The Second Department of Internal Medicine, Faculty of Medicine, Kagoshima University, Japan
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24
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Kappers-Klunne MC, de Haan M, Struijk PC, van Vliet HH. Serum thrombopoietin levels in relation to disease status in patients with immune thrombocytopenic purpura. Br J Haematol 2001; 115:1004-6. [PMID: 11843841 DOI: 10.1046/j.1365-2141.2001.03184.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pre- and post-treatment serum thrombopoietin (TPO) concentration was measured in 35 patients with immune thrombocytopenic purpura (ITP). Mean post-treatment levels were significantly lower (P = 0.02) than pretreatment and not different for treatment modality. No significant correlation between pre- or post-treatment TPO and platelet counts was demonstrable (R = -0.325, P = 0.056 and R = -0.227, P = 0.190 respectively). In patients with very low platelet counts (< or =20 x 10(9)/l), pretreatment serum TPO was significantly higher than in patients with higher counts (P = 0.033). The logarithm of the platelet turnover rate, measured in 15 patients, correlated with pretreatment TPO levels (R = 0.64). These findings suggest a contributory role for TPO in the mechanism of ITP.
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Affiliation(s)
- M C Kappers-Klunne
- Department of Haematology, University Hospital Rotterdam, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
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25
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Gouin-Thibault I, Cassinat B, Chomienne C, Rain JD, Najean Y, Schlageter MH. Is the Thrombopoietin Assay Useful for Differential Diagnosis of Thrombocytopenia? Analysis of a Cohort of 160 Patients with Thrombocytopenia and Defined Platelet Life Span. Clin Chem 2001. [DOI: 10.1093/clinchem/47.9.1660] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Background: Thrombopoietin (TPO), the major hormone controlling platelet production, has been measured in thrombocytopenias with discordant results. The aim of our work was to assess the value of the TPO assay for differential diagnosis of thrombocytopenias in a large cohort of patients classified according to the results of their platelet isotopic study.
Methods: We measured TPO (R&D Systems) in serum of 160 thrombocytopenic patients referred to our department for platelet life span isotopic studies. We classified patients as follows: (a) idiopathic or autoimmune thrombocytopenia group (ITP; patients with increased platelet destruction and shortened platelet life span; n = 67); (b) pure genetic thrombocytopenia group (patients with decreased platelet production, normal platelet life span, and without bone marrow aplasia; n = 55); (c) bone marrow aplasia group (BM; patients with decreased platelet production, normal platelet life span, and bone marrow aplasia; n = 13).
Results: In patients with pure genetic thrombocytopenia, TPO (median, 55 ng/L) was not different from TPO in patients with ITP (median, 58 ng/L) or controls (n = 54; median, 51 ng/L). Only in patients with bone marrow aplasia was TPO significantly higher (median, 155 ng/L) and negatively correlated to the platelet count (r2 = 0.5014).
Conclusions: Although the median serum TPO is increased in thrombocytopenia with decreased platelet production from bone marrow aplasia, it does not differentiate patients with pure genetic thrombocytopenia from those with ITP.
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Affiliation(s)
- Isabelle Gouin-Thibault
- Service de Médecine Nucléaire, Hôpital Saint-Louis, Assistance Publique, Hôpitaux de Paris, 1, Avenue Claude Vellefaux, 75475 Paris Cedex 10, France
- Laboratoire d’Hématologie, Groupe Hospitalier Charles Foix-Jean Rostand, Assistance Publique, Hôpitaux de Paris, 7, Avenue de la République, 94205 Ivry Sur Seine Cedex 5, France
| | - Bruno Cassinat
- Service de Médecine Nucléaire, Hôpital Saint-Louis, Assistance Publique, Hôpitaux de Paris, 1, Avenue Claude Vellefaux, 75475 Paris Cedex 10, France
| | - Christine Chomienne
- Service de Médecine Nucléaire, Hôpital Saint-Louis, Assistance Publique, Hôpitaux de Paris, 1, Avenue Claude Vellefaux, 75475 Paris Cedex 10, France
| | - Jean-Didier Rain
- Service de Médecine Nucléaire, Hôpital Saint-Louis, Assistance Publique, Hôpitaux de Paris, 1, Avenue Claude Vellefaux, 75475 Paris Cedex 10, France
| | - Yves Najean
- Service de Médecine Nucléaire, Hôpital Saint-Louis, Assistance Publique, Hôpitaux de Paris, 1, Avenue Claude Vellefaux, 75475 Paris Cedex 10, France
| | - Marie-Hélène Schlageter
- Service de Médecine Nucléaire, Hôpital Saint-Louis, Assistance Publique, Hôpitaux de Paris, 1, Avenue Claude Vellefaux, 75475 Paris Cedex 10, France
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26
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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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Nichol JL. Endogenous TPO (eTPO) levels in health and disease: possible clues for therapeutic intervention. Stem Cells 2001; 16 Suppl 2:165-75. [PMID: 11012188 DOI: 10.1002/stem.5530160719] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The factor which is the primary regulator of megakaryocyte and platelet production has recently been identified as the ligand for the receptor Mpl. This discovery has resulted in substantial advances in our understanding of platelet homeostasis. The access to new experimental reagents has enabled studies of the endogenous circulating form of this ligand, endogenous thrombopoietin, in normal individuals and in patients with altered platelet numbers. The relationship of endogenous TPO in health and disease will be examined with consideration of the implications for successful therapeutic intervention with exogenous recombinant Mpl ligands in selected settings.
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Affiliation(s)
- J L Nichol
- Amgen, Inc., Thousand Oaks, California, USA
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Wang W, Matsuo T, Yoshida S, Mori H, Miyazaki Y, Kuriyama K, Tomonaga M. Colony-forming unit-megakaryocyte (CFR-meg) numbers and serum thrombopoietin concentrations in thrombocytopenic disorders: an inverse correlation in myelodysplastic syndromes. Leukemia 2000; 14:1751-6. [PMID: 11021750 DOI: 10.1038/sj.leu.2401898] [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: 11/08/2022]
Abstract
We studied both serum-free colony-forming unit-megakaryocyte (CFU-meg) numbers and serum thrombopoietin (TPO) levels in 14 patients with aplastic anemia (AA), 37 patients with myelodysplastic syndromes (MDS) and 23 patients with idiopathic thrombocytopenic purpura (ITP) to assess thrombopoiesis in these thrombocytopenic disorders. The mean CFU-meg numbers were lower in AA and MDS patients (10.7 +/- 11.4 and 42.3 +/- 58.5/10(5) BMLD cells) than in healthy controls (103.1 +/- 57.3/10(5) BMLD cells) (P < 0.0001 and P= 0.0053, respectively), although they were distributed variably in MDS. ITP patients showed higher CFU-meg numbers (223.2 +/- 143.5/10(5) BMLD cells) (P= 0.017). The mean TPO concentrations were higher in both AA (986.8 +/- 500.8 pg/ml) and MDS patients (838.2 +/- 639.1 pg/ml) than in healthy controls (80.7 +/- 38.8 pg/ml) (P < 0.0001), although they were distributed from high to low in MDS. ITP patients showed a slight elevation of TPO (123.1 +/- 55.3 pg/ml) P = 0.0106). The TPO levels was inversely correlated to both platelet counts and CFU-meg numbers (correlative coefficient (CC): -0.719 and -0.682, P < 0.0001) in AA, but not in ITP. In MDS, the inverse correlation to TPO was stronger in CFU-meg (CC: -0.678, P < 0.0001) than in platelet counts (CC: -0.538, P = 0.0014), suggesting that CFU-meg plays an important role in regulating TPO production in this heterogenous disorder. CFU-meg and TPO may provide useful information for understanding thrombopoiesis of MDS, especially for application of TPO.
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Affiliation(s)
- W Wang
- Department of Hematology, Atomic Bomb Disease Institute, Nagasaki University School of Medicine, Japan
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Abstract
C-mpl ligand or thrombopoietin (Tpo) is increasingly recognised as the major regulator of platelet homeostasis in humans. Relatively little is known about Tpo in the fetus and neonate but no evidence has yet been found to suggest any fundamental difference in Tpo structure, function and regulation in the fetus and neonate compared to older age groups. Tpo mRNA transcripts have been detected in the fetus as early as 6 weeks post conception and the liver appears to be the main site of Tpo production in both the fetus and neonate. The vast majority of healthy newborns have detectable levels of circulating Tpo and raised Tpo levels are commonly, but not consistently, found in thrombocytopenic neonates. In adults receptor binding and subsequent metabolism of Tpo is proposed as the main method of regulation of the circulating Tpo level. Preliminary studies in neonates showing increased Tpo levels most often during thrombocytopenia accompanied by reduced megakaryocytopoiesis supports this concept. In addition to this demonstrable fetal and neonatal endogenous Tpo production megakaryocyte progenitor and precursor cells from the fetus and from preterm and term newborns proliferate and differentiate extensively in-vitro in response to exogenous Tpo. Furthermore a recent study has shown a marked rise in platelet count in newborn rhesus monkeys administered one form of recombinant Tpo. Although these studies remain at an early stage together these findings strongly suggest that, as in adults, Tpo is the major regulator of platelet homeostasis in the fetus and neonate. Thrombocytopenia is common in sick neonates and progress in understanding this important clinical problem is likely to be greatly enhanced by the current and future research into Tpo production, function and regulation in the healthy and thrombocytopenic fetus and neonate.
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Affiliation(s)
- N A Murray
- Department of Neonatal Medicine, Imperial College School of Medicine, Hammersmith Campus, Hammersmith Hospital, Du Cane Road, W12 ONN, London, UK.
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Verbeek W, Faulhaber M, Griesinger F, Brittinger G. Measurement of thrombopoietic levels: clinical and biological relationships. Curr Opin Hematol 2000; 7:143-9. [PMID: 10786650 DOI: 10.1097/00062752-200005000-00003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Platelet production is primarily regulated by the thrombopoietic cytokine thrombopoietin (TPO). In most cases thrombopoietin serum levels are determined by the rate of c-mpl receptor-mediated degradation after TPO uptake into platelets and megakaryocytes. The contribution of increased TPO protein synthesis by a translational mechanism was recently appreciated as the cause for hereditary thrombocythemia and will have to be elucidated in other conditions of thrombocytosis in association with increased TPO levels.
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Affiliation(s)
- W Verbeek
- Department of Medicine, Georg August University, Göttingen, Germany
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Hellström-Lindberg E, Kanter-Lewensohn L, Nichol J, Ost A. Spontaneous and cytokine-induced thrombocytopenia in myelodysplastic syndromes: serum thrombopoietin levels and bone marrow morphology. Scandinavian MDS Group, Sweden and Norway. Br J Haematol 1999; 105:966-73. [PMID: 10554808 DOI: 10.1046/j.1365-2141.1999.01442.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Thrombocytopenia is a substantial clinical problem for patients with myelodysplastic syndromes (MDS). Cytokine treatment for granulocytopenia and anaemia may further reduce the platelet counts. We studied serum thrombopoietin levels (S-TPO) in 52 patients with MDS and 96 healthy controls and related the results to clinical and morphological variables. S-TPO was also assessed after treatment with granulocyte-CSF (G-CSF) and erythropoietin (EPO) in 30 of these patients. S-TPO in MDS was not a normally distributed variable; mean value was 394 pg/ml, SD +/-831 and median value 123 (12-5000 pg/ml). The controls showed lower S-TPO levels than the patients (median 78 pg/ml, P = 0.003) whereas no differences between the MDS subgroups were observed (P = 0.86). Patients with ringed sideroblastic anaemia (RARS) showed the highest platelet counts and higher S-TPO levels than the controls (P = 0.005). No association between platelet counts and S-TPO levels was found in the patients (P = 0.67). TPO levels were generally low in patients with refractory anaemia with an excess of blasts (RAEB), but very high levels were found in five patients. Patients with a high transfusion need had higher S-TPO levels, whereas bone marrow blast counts, cellularity or megakaryocytes showed no correlation with S-TPO. Patients with 5q- showed lower TPO levels than the other patients, indicating that thrombopoietin is not a mediator of thrombocytosis in these cases. Treatment with G-CSF + EPO significantly reduced the platelet counts (P = 0.0002), but this change was not related to significant changes in S-TPO levels or morphology. Patients with RARS and thrombocytosis who normalized their platelet counts showed a concomitant reduction in S-TPO. This may suggest that the increased platelet counts observed in RARS may be caused by increased S-TPO levels. In conclusion, our study shows that platelet, megakaryocyte and thrombopoietin regulation is rather complex in myelodysplastic syndromes and that spontaneous or induced thrombocytopenia are not usually mirrored by increased S-TPO levels.
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Kinjo K, Kizaki M, Takayama N, Michikawa N, Oda A, Okamoto SI, Tahara T, Kato T, Miyazaki H, Ikeda Y. Serum thrombopoietin and erythropoietin levels in patients with acute promyelocytic leukaemia during all-trans retinoic acid treatment. Br J Haematol 1999. [DOI: 10.1111/j.1365-2141.1999.01341.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Louwes H, Zeinali Lathori OA, Vellenga E, de Wolf JT. Platelet kinetic studies in patients with idiopathic thrombocytopenic purpura. Am J Med 1999; 106:430-4. [PMID: 10225246 DOI: 10.1016/s0002-9343(99)00054-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine the value in diagnosis and treatment of mean platelet life, platelet production, and major sites of platelet destruction in patients with idiopathic thrombocytopenic purpura (ITP). PATIENTS AND METHODS Sternal or posterior superior iliac spine bone marrow aspiration was performed in 141 patients. Platelet kinetic studies with Indium-111 tropolonate labeled autologous platelets were utilized to determine platelet production. RESULTS Two subgroups of patients could be defined. The first group (n = 81, 58%) had normal or increased platelet production and increased peripheral platelet destruction. These patients fulfilled the conventional criteria for ITP, including reduced platelet survival time (mean +/- SD, 1.6 +/- 1.4 days). Forty-eight (59%) of these patients had increased splenic sequestration and 30 (88%) of the 34 patients who underwent splenectomy had a complete or partial remission. The second group (n = 60, 42%) had decreased platelet production, with significantly greater platelet survival times (3.6 +/- 2 days, P <0.0001). In this group, the proportion of patients with complete or partial response to splenectomy (62%) was somewhat lower (P = 0.09). These patients mainly had ineffective platelet production in the bone marrow. CONCLUSIONS Platelet kinetic studies suggest that ITP is a heterogeneous disease that comprises two subgroups. Further studies are needed to validate these findings and to determine their effect on the choice and outcome of therapy.
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Affiliation(s)
- H Louwes
- Department of Nuclear Medicine, Martini Hospital, Groningen, The Netherlands
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von dem Borne AE, Folman C, Linthorst GE, Porcelijn L, van den Oudenrijn S, van der Schoot E, de Haas M. Thrombopoietin: its role in platelet disorders and as a new drug in clinical medicine. BAILLIERE'S CLINICAL HAEMATOLOGY 1998; 11:427-45. [PMID: 10097818 DOI: 10.1016/s0950-3536(98)80059-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- A E von dem Borne
- Department of Hematology, Academic Medical Centre, Amsterdam, The Netherlands
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Manley R, Murphy MF. Thrombocytopenia-Platelet Support or Growth Factors? Hematology 1998; 3:469-82. [PMID: 27420334 DOI: 10.1080/10245332.1998.11746421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The prevention and treatment of hemorrhage in patients with severe thrombocytopenia following cytotoxic chemotherapy and/or radiotherapy remain important issues in the supportive care of these patients. Platelet transfusions have been available for this purpose for over 30 years, and there have been recent initiatives to refine the way in which they are used and to improve their safety. An alternative to platelet transfusions is the enhancement of platelet recovery through the use of hemopoietic growth factors, and the recent identification of thrombopoietin and its potential for clinical use are exciting developments. Further work is needed to ensure its safety, and to define the appropriate indications for its use. Another alternative to platelet transfusions is the use of platelet substitutes, and a number of products are being developed. The clinical use of hemopoietic growth factors and platelet substitutes raises the prospect of reducing the current high demand for platelet concentrates. However, it remains to be seen whether their potential will be fully realised, and platelet transfusions will continue to be needed for the forseeable future.
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Affiliation(s)
- R Manley
- a Department of Haematology , The John Radcliffe Hospital , Oxford , UK
| | - M F Murphy
- a Department of Haematology , The John Radcliffe Hospital , Oxford , UK.,b National Blood Service , The John Radcliffe Hospital , Oxford , UK
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