1
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Takeshita S, Kakita H, Toriuchi K, Aoki H, Ueda H, Wakatsuki A, Yamada Y, Aoyama M. Insufficient thrombopoietin due to hepatic dysmature results in thrombocytopenia in small-for-gestational-age rats. Br J Haematol 2021; 192:e105-e108. [PMID: 33403676 DOI: 10.1111/bjh.17294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/26/2020] [Accepted: 12/01/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Satoru Takeshita
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabe-dori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan.,Department of Perinatal and Neonatal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Hiroki Kakita
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabe-dori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan.,Department of Perinatal and Neonatal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Kohki Toriuchi
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabe-dori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan
| | - Hiromasa Aoki
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabe-dori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan
| | - Hiroko Ueda
- Department of Perinatal and Neonatal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Akihiko Wakatsuki
- Department of Obstetrics and Gynecology, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Yasumasa Yamada
- Department of Perinatal and Neonatal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Mineyoshi Aoyama
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabe-dori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan
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2
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Go H, Ohto H, Nollet KE, Kashiwabara N, Chishiki M, Hoshino M, Ogasawara K, Kawasaki Y, Momoi N, Hosoya M. Perinatal factors affecting platelet parameters in late preterm and term neonates. PLoS One 2020; 15:e0242539. [PMID: 33211743 PMCID: PMC7676724 DOI: 10.1371/journal.pone.0242539] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 11/04/2020] [Indexed: 12/21/2022] Open
Abstract
Platelets parameters including platelet count (PLT), plateletcrit (PCT), mean platelet volume (MPV) and platelet distribution width (PDW) are associated with various physiological and pathological functions in various disease. However, few studies have addressed whether perinatal factors may be associated with platelet parameters at birth in a large cohort of late preterm and term neonates. The aim of this study to investigate perinatal factors affecting platelet parameters in late preterm and term neonates. We retrospectively investigated platelet parameters including PLT, PCT, MPV, and PDW on the first day of life in 142 late preterm and 258 term neonates admitted to our NICU from 2006 through 2020. PLT, MPV, PCT, PDW on Day 0 did not significantly differ between the two groups. In term neonates, multivariate analysis revealed that PCT correlated with being small for gestational age (SGA) (β = -0.168, P = 0.006), pregnancy induced hypertension (PIH) (β = -0.135, P = 0.026) and male sex (β = -0.185, P = 0.002). PLT was associated with SGA (β = -0.186, P = 0.002), PIH (β = -0.137, P = 0.024) and male sex (β = -0.166, P = 0.006). In late preterm neonates, multivariate analysis revealed that PLT were associated with PIH, whereas no factors associated with PDW and MPV were found. In all patients studied, chorioamnionitis (CAM) was significantly associated with MPV (CAM = 10.3 fL vs. no CAM = 9.7 fL, P<0.001). Multivariate analysis showed that SGA, male sex and PIH were associated with PCT and PLT. This study demonstrates that different maternal and neonatal complications affect platelet parameters in late preterm and term neonates.
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Affiliation(s)
- Hayato Go
- Department of Pediatrics, Fukushima Medical University School of Medicine, Fukushima, Japan
- * E-mail:
| | - Hitoshi Ohto
- Department of Advanced Cancer Immunotherapy, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Kenneth E. Nollet
- Department of Blood Transfusion and Transplantation Immunology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Nozomi Kashiwabara
- Department of Pediatrics, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Mina Chishiki
- Department of Pediatrics, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Masato Hoshino
- Department of Pediatrics, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Kei Ogasawara
- Department of Pediatrics, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Yukihiko Kawasaki
- Department of Pediatrics, Sapporo Medical University School of Medicine, Hokkaido, Japan
| | - Nobuo Momoi
- Department of Pediatrics, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Mitsuaki Hosoya
- Department of Pediatrics, Fukushima Medical University School of Medicine, Fukushima, Japan
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3
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Kim JS, Kim JY. Neonatal Thrombocytopenia: Diagnostic Approach and Platelet Transfusion Guideline. CLINICAL PEDIATRIC HEMATOLOGY-ONCOLOGY 2019. [DOI: 10.15264/cpho.2019.26.2.67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Ji Sook Kim
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Ji Yoon Kim
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu, Korea
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4
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Esiaba I, Mousselli I, M. Faison G, M. Angeles D, S. Boskovic D. Platelets in the Newborn. NEONATAL MEDICINE 2019. [DOI: 10.5772/intechopen.86715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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5
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Mahat U, Talati R, Kodish E. Comment on: Use of thrombopoietin receptor agonist (romiplostim) in neonatal autoimmune thrombocytopenia due to maternal immune thrombocytopenia. Pediatr Blood Cancer 2019; 66:e27706. [PMID: 30854752 DOI: 10.1002/pbc.27706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Upendra Mahat
- Pediatric Hematology Oncology, Cleveland Clinic Children's, Cleveland, Ohio
| | - Ravi Talati
- Pediatric Hematology Oncology, Cleveland Clinic Children's, Cleveland, Ohio
| | - Eric Kodish
- Pediatric Hematology Oncology, Cleveland Clinic Children's, Cleveland, Ohio
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7
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Abstract
Platelets undergo a process of developmental maturation, and hence its regulation of vascular integrity and control of hemostasis at various stages of neonatal ages deserves better characterization. Functional assays for platelets require a larger volume of blood than what is feasible to collect in neonates, creating a technical hurdle that has been a challenge to investigate neonatal platelets. For this reason, the current knowledge of neonatal platelet function has been based on studies from cord blood-derived platelets as a surrogate for neonatal peripheral blood. Studies indicate that neonatal platelets are hypofunctional to various agonists, although neonates tend to maintain normal hemostasis. This apparently paradoxical finding may be due to several factors, such as elevated functionally potent von Willebrand factor multimers or hematocrit levels, in the neonatal blood that enhance the platelet and vessel wall interaction, and counteract platelet hyporeactivity. This review describes the functional characteristics of neonatal platelets, differences in platelet reactivity between neonates and adults, and potential biomarkers of platelet activation.
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Affiliation(s)
- Belay Tesfamariam
- Division of Cardiovascular and Renal Products, Center for Drug Evaluation and Research, FDA, 10903 New Hampshire Ave, Bldg 22, Rm 4176, Silver Spring, MD 20993, United States.
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8
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Sparger KA, Ramsey H, Lorenz V, Liu ZJ, Feldman HA, Li N, Laforest T, Sola-Visner MC. Developmental differences between newborn and adult mice in response to romiplostim. Platelets 2017; 29:365-372. [PMID: 28548028 DOI: 10.1080/09537104.2017.1316481] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Thrombocytopenia is frequent among sick neonates. While most cases are transient, some neonates experience prolonged and severe thrombocytopenia. These infants often pose diagnostic and therapeutic challenges, and may receive large numbers of platelet transfusions. Romiplostim (ROM) is a thrombopoietin (TPO)-receptor-agonist approved for treatment of adults with chronic immune thrombocytopenia (ITP). The immature platelet fraction (IPF) is a novel measure of newly produced platelets, which could aid with the diagnostic evaluation of thrombocytopenic neonates. This study had the following two objectives: (1) compare the response of newborn and adult mice to escalating doses of ROM in vivo and (2) assess the correlation between IPF and megakaryocyte (MK) mass in newborn and adult treated and untreated mice. In the first set of studies, newborn (day 1) and adult mice received a single subcutaneous (SC) dose of ROM ranging from 0 to 300 ng/g, and platelet counts were followed every other day for 14 days. Both sets of mice responded with dose-dependent platelet and IPF increases, peaking on days 5-7 post-treatment, but neonates had a blunted response (2.1-fold compared to 4.2-fold maximal increase in platelet counts, respectively). On day 5 post-treatment with 300 ng/g ROM, MKs in the bone marrow (BM) and spleen of adult mice were significantly increased in numbers and size (p < 0.0001 for both) compared to controls. MKs in the spleen and BM (but not liver) of treated neonates also increased in number, but not in size. The immature platelet count (IPC, calculated as IPF x platelet count) was highly correlated with the MK number and size in neonatal and adult BM and spleen, but not neonatal liver. The lack of response of neonatal liver MKs was not due to a cell-intrinsic reduced responsiveness to TPO, since neonatal liver progenitors were more sensitive to murine TPO (mTPO) in vitro than adult BM progenitor. In vivo treatment of newborn mice with high mTPO doses or with higher doses of ROM (900 ng/g) resulted in peak platelet counts approaching 3-fold of controls. Taken together, our data indicate that newborn mice are less responsive to ROM than adult mice in vivo, due to a combination of likely pharmacokinetic differences and developmental differences in the response of MKs to thrombopoietic stimulation, evidenced by neonatal MKs increasing in numbers but not in size. PK/PD studies in human infants treated with ROM are warranted.
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Affiliation(s)
- Katherine A Sparger
- a Division of Newborn Medicine , Boston Children's Hospital , Boston , MA , USA.,b Division of Neonatology , Massachusetts General Hospital for Children , Boston , MA , USA
| | - Haley Ramsey
- a Division of Newborn Medicine , Boston Children's Hospital , Boston , MA , USA
| | - Viola Lorenz
- a Division of Newborn Medicine , Boston Children's Hospital , Boston , MA , USA
| | - Zhi-Jian Liu
- a Division of Newborn Medicine , Boston Children's Hospital , Boston , MA , USA
| | - Henry A Feldman
- c Clinical Research Center , Boston Children's Hospital , Boston , MA , USA
| | - Nan Li
- a Division of Newborn Medicine , Boston Children's Hospital , Boston , MA , USA
| | - Tahirih Laforest
- a Division of Newborn Medicine , Boston Children's Hospital , Boston , MA , USA
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9
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Cremer M, Sallmon H, Kling PJ, Bührer C, Dame C. Thrombocytopenia and platelet transfusion in the neonate. Semin Fetal Neonatal Med 2016; 21:10-8. [PMID: 26712568 DOI: 10.1016/j.siny.2015.11.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Neonatal thrombocytopenia is widespread in preterm and term neonates admitted to neonatal intensive care units, with up to one-third of infants demonstrating platelet counts <150 × 10(9)/L. Thrombocytopenia may arise from maternal, placental or fetal/neonatal origins featuring decreased platelet production, increased consumption, or both mechanisms. Over the past years, innovations in managing neonatal thrombocytopenia were achieved from prospectively obtained clinical data on thrombocytopenia and bleeding events, animal studies on platelet life span and production rate and clinical use of fully automated measurement of reticulated platelets (immature platelet fraction). This review summarizes the pathophysiology of neonatal thrombocytopenia, current management including platelet transfusion thresholds and recent developments in megakaryopoietic agents. Furthermore, we propose a novel index score for bleeding risk in thrombocytopenic neonates to facilitate clinician's decision-making when to transfuse platelets.
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Affiliation(s)
- Malte Cremer
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany.
| | - Hannes Sallmon
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - Pamela J Kling
- Department of Pediatrics, University of Wisconsin - Madison, Madison, WI, USA
| | - Christoph Bührer
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - Christof Dame
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
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10
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Abstract
Similarly to the development of the plasma coagulation system, which matures during the early weeks and months of life, age-dependent mechanisms and developmental changes influence platelet production and function in neonates. Platelet function testing on cord blood and peripheral blood demonstrates a generalized platelet hyporeactivity, during the first days of life. This reactivity reaches normal adult levels between the fifth and ninth day of life. The persistence of hyporeactivity after the tenth day of life might indeed suggest a platelet disorder.
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Affiliation(s)
- Antonio Del Vecchio
- Neonatal Intensive Care Unit, Di Venere Hospital, Via Ospedale Di Venere n.1, Bari 70131, Italy.
| | - Mario Motta
- Neonatology and Neonatal Intensive Care Unit, Children's Hospital of Brescia, Brescia, Italy
| | - Costantino Romagnoli
- Neonatal Intensive Care Unit, Division of Neonatology, Department of Pediatrics, Catholic University of the Sacred Heart, Rome, Italy
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11
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Christensen RD, Baer VL, Henry E, Snow GL, Butler A, Sola-Visner MC. Thrombocytopenia in Small-for-Gestational-Age Infants. Pediatrics 2015; 136. [PMID: 26216323 PMCID: PMC4906543 DOI: 10.1542/peds.2014-4182] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Thrombocytopenia is common among small-for-gestational-age (SGA) neonates (birth weight <10th percentile reference range), but several aspects of this thrombocytopenia are unclear, including the incidence, typical nadir, duration, association with preeclampsia, mechanism, and risk of death. METHODS Using 9 years of multihospital records, we studied SGA neonates with ≥2 platelet counts <150,000/μL in their first week. RESULTS We found first-week thrombocytopenia in 31% (905 of 2891) of SGA neonates versus 10% of non-SGA matched controls (P < .0001). Of the 905, 102 had a recognized cause of thrombocytopenia (disseminated intravascular coagulation, early-onset sepsis, or extracorporeal membrane oxygenation). This group had a 65% mortality rate. The remaining 803 did not have an obvious cause for their thrombocytopenia, and we called this "thrombocytopenia of SGA." They had a mortality rate of 2% (P < .0001) and a mean nadir count on day 4 of 93,000/μL (SD 51,580/μL, 10th percentile 50,000/μL, 90th percentile 175,000/μL). By day 14, platelet counts were ≥150,000/μL in more than half of the patients. Severely SGA neonates (<1st percentile) had lower counts and longer thrombocytopenia duration (P < .001). High nucleated red cell counts at birth correlated with low platelets (P < .0001). Platelet transfusions were given to 23%, and counts typically more than tripled. Thrombocytopenia was more associated with SGA status than with the diagnosis of maternal preeclampsia. CONCLUSIONS SGA neonates with clearly recognized varieties of thrombocytopenia have a high mortality rate. In contrast, thrombocytopenia of SGA is a hyporegenerative condition of moderate severity and 2 weeks' duration and is associated with evidence of intrauterine hypoxia and a low mortality rate.
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Affiliation(s)
- Robert D. Christensen
- Divisions of Hematology/Oncology, and,Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah;,Primary Children’s Hospital, Salt Lake City, Utah;,Address correspondence to Robert D. Christensen, MD, University of Utah Department of Pediatrics, 295 Chipeta Way, Salt Lake City, UT 84108. E-mail:
| | - Vickie L. Baer
- Women and Newborn’s Clinical Program, Intermountain Healthcare, Salt Lake City, Utah
| | - Erick Henry
- Primary Children’s Hospital, Salt Lake City, Utah
| | - Gregory L. Snow
- Statistical Data Center, LDS Hospital, Salt Lake City, Utah; and
| | - Allison Butler
- Statistical Data Center, LDS Hospital, Salt Lake City, Utah; and
| | - Martha C. Sola-Visner
- Division of Neonatal Medicine, Children’s Hospital and Harvard Medical School, Boston, Massachusetts
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12
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Yang J, Zhang H, Niu J, Mu X, Zhang X, Liu Y, Wang J, Chen Y. Impact of preeclampsia on megakaryocytopoesis and platelet homeostasis of preterm infants. Platelets 2015; 27:123-7. [DOI: 10.3109/09537104.2015.1048213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Abstract
Thrombocytopenia is a very frequent problem among sick neonates, affecting up to 35% of all infants admitted to the neonatal intensive care unit (NICU), and serves as an important indicator of multiple clinical conditions. The cause of the thrombocytopenia is unclear in up to 60% of affected neonates. A clinical classification of thrombocytopenia is based on the time of presentation, early (≤72 hours of life) vs. late (>72 hours of life). Early thrombocytopenia is commonly associated with feto-maternal conditions, is most commonly caused by disorders associated with placental insufficiency, and is generally mild to moderate and resolves spontaneously within 7-10 days without any intervention. In contrast, neonates who develop late-onset thrombocytopenia frequently have bacterial sepsis or necrotizing enterocolitis. It is often severe (platelets <50,000/μL), prolonged and frequently requires multiple platelet transfusions. Platelet transfusions represent the only specific therapy currently available for most thrombocytopenic neonates, even though much evidence suggests that platelet transfusions are not benign. Many of the prophylactic platelet transfusions currently given to NICU patients are unnecessary, convey no benefits, and carry known and unknown risks. For this reason, pharmacological alternatives have been investigated as potential therapies for thrombocytopenia, but they still have limited use treating the common varieties of neonatal thrombocytopenia.
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Affiliation(s)
- Antonio Del Vecchio
- Department of Maternal and Child Health, Division of Neonatology, Neonatal Intensive Care Unit, Di Venere Hospital, Bari, Italy.
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14
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Copley MR, Eaves CJ. Developmental changes in hematopoietic stem cell properties. Exp Mol Med 2013; 45:e55. [PMID: 24232254 PMCID: PMC3849580 DOI: 10.1038/emm.2013.98] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 07/29/2013] [Indexed: 01/18/2023] Open
Abstract
Hematopoietic stem cells (HSCs) comprise a rare population of cells that can regenerate and maintain lifelong blood cell production. This functionality is achieved through their ability to undergo many divisions without activating a poised, but latent, capacity for differentiation into multiple blood cell types. Throughout life, HSCs undergo sequential changes in several key properties. These affect mechanisms that regulate the self-renewal, turnover and differentiation of HSCs as well as the properties of the committed progenitors and terminally differentiated cells derived from them. Recent findings point to the Lin28b-let-7 pathway as a master regulator of many of these changes with important implications for the clinical use of HSCs for marrow rescue and gene therapy, as well as furthering our understanding of the different pathogenesis of childhood and adult-onset leukemia.
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15
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Al-Tonbary Y, Al-Haggar M, Salama O, Abul-Kheir M, El-Alfy A, Hafez M. Platelet count and serum thrombopoietin level as predictors for morbidity and/or mortality in thrombocytopenic neonates. Hematology 2012; 17:341-5. [DOI: 10.1179/1607845412y.0000000026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Affiliation(s)
- Youssef Al-Tonbary
- Hematology/Oncology/BMT UnitMansoura University Children's Hospital, Mansoura University, Egypt
| | - Mohammad Al-Haggar
- Hematology/Oncology/BMT UnitMansoura University Children's Hospital, Mansoura University, Egypt
| | - Osama Salama
- Hematology/Oncology/BMT UnitMansoura University Children's Hospital, Mansoura University, Egypt
| | - Magdy Abul-Kheir
- Hematology/Oncology/BMT UnitMansoura University Children's Hospital, Mansoura University, Egypt
| | - Abla El-Alfy
- Hematology/Oncology/BMT UnitMansoura University Children's Hospital, Mansoura University, Egypt
| | - Mohammad Hafez
- Hematology/Oncology/BMT UnitMansoura University Children's Hospital, Mansoura University, Egypt
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16
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Abstract
Background: Neonates often develop thrombocytopenia at some time during hospital stay. Platelet transfusion are frequently given to them and are likely to result in unnecessary transfusion. Material and Methods: Thus, we analyzed thrombocytopenia in neonates, its prevalence, and relationship if any, between clinical condition and platelet transfusion in neonates, which would have been helpful in developing guidelines and/or protocols for platelet transfusion (and reducing the donor exposure) in neonates. Results: A total of 870 neonates who were admitted in Neonatal Intensive Care Unit (NICU) with various morbidities had platelets count done; of these, 146 (16.7%) neonate revealed thrombocytopenia. Discussion: Low birth weight babies (P 0.009) and babies born with mother having hypertension (P 0.04) showed significant thrombocytopenia. Neonates with intrauterine growth retardation (IUGR) diagnosed during antenatal screening showed lower platelet count (P 0.022). Neonates having associated illness, such as sepsis, gastrointestinal, and respiratory problems, and on vasopressor drugs were found to be associated with low platelet count. Conclusion: In our study, 16.40% of thrombocytopenic neonates required platelet transfusion either alone or with other blood component during their stay in NICU.
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Affiliation(s)
- Anil K Gupta
- Department of Transfusion Medicine, Centre for Newborn Care, Delhi, India
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17
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Abstract
PURPOSE OF REVIEW It has become increasingly clear that there are substantial biological differences between fetal/neonatal and adult megakaryopoiesis. Over the last 18 months, studies challenged the paradigm that neonatal megakaryocytes are immature and revealed a developmentally unique uncoupling of proliferation, polyploidization, and cytoplasmic maturation. Several studies also described substantial molecular differences between fetal/neonatal and adult megakaryocytes involving transcription factors, signaling pathways, cytokine receptors, and microRNAs. RECENT FINDINGS This review will summarize our current knowledge on the developmental differences between fetal/neonatal and adult megakaryocytes, and recent advances in the underlying molecular mechanisms, including differences in transcription factors, in the response to thrombopoietin (Tpo), and newly described developmentally regulated signaling pathways. We will also discuss the implications of these findings on the way megakaryocytes interact with the environment, the response of neonates to thrombocytopenia, and the pathogenesis of Down syndrome-transient myeloproliferative disorder (TMD) and Down syndrome-acute megakaryoblastic leukemia (DS-AMKL). SUMMARY A better characterization of the molecular differences between fetal/neonatal and adult megakaryocytes is critical to elucidating the pathogenesis of a group of disorders that selectively affect fetal/neonatal megakaryocyte progenitors, including the thrombocytopenia-absent radius (TAR) syndrome, Down syndrome-TMD or Down syndrome-AMKL, and the delayed platelet engraftment following cord blood transplantation.
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18
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Abstract
The haemostatic system is a complex interaction between the vasculature, cellular components and plasma proteins that interact to maintain haemostasis in the healthy body. The haemostatic system can be further defined as primary, secondary and tertiary haemostasis to better define the interdependent mechanisms that combine to maintain haemostasis. The term 'developmental haemostasis' was first introduced by Maureen Andrews in the 1980s to describe the age-related physiological changes of the coagulation system as it develops progressively over time from fetal, neonatal, paediatric to adult and geriatric systems. This paper will focus on developmental changes in secondary haemostasis, that is, the plasma protein changes that occur with age, particularly during the fetal and neonatal period, when the changes are most marked compared to the adult system.
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Affiliation(s)
- Paul Monagle
- Department of Clinical Haematology, Royal Children's Hospital, Melbourne, Australia.
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19
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Developmental differences in megakaryocytopoiesis are associated with up-regulated TPO signaling through mTOR and elevated GATA-1 levels in neonatal megakaryocytes. Blood 2011; 117:4106-17. [PMID: 21304100 DOI: 10.1182/blood-2010-07-293092] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Multiple observations support the existence of developmental differences in megakaryocytopoiesis. We have previously shown that neonatal megakaryocyte (MK) progenitors are hyperproliferative and give rise to MKs smaller and of lower ploidy than adult MKs. Based on these characteristics, neonatal MKs have been considered immature. The molecular mechanisms underlying these differences are unclear, but contribute to the pathogenesis of disorders of neonatal megakaryocytopoiesis. In the present study, we demonstrate that low-ploidy neonatal MKs, contrary to traditional belief, are more mature than adult low-ploidy MKs. These mature MKs are generated at a 10-fold higher rate than adult MKs, and result from a developmental uncoupling of proliferation, polyploidization, and terminal differentiation. This pattern is associated with up-regulated thrombopoietin (TPO) signaling through mammalian target of rapamycin (mTOR) and elevated levels of full-length GATA-1 and its targets. Blocking of mTOR with rapamycin suppressed the maturation of neonatal MKs without affecting ploidy, in contrast to the synchronous inhibition of polyploidization and cytoplasmic maturation in adult MKs. We propose that these mechanisms allow fetuses/neonates to populate their rapidly expanding bone marrow and intravascular spaces while maintaining normal platelet counts, but also set the stage for disorders restricted to fetal/neonatal MK progenitors, including the Down syndrome-transient myeloproliferative disorder and the thrombocytopenia absent radius syndrome.
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20
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Ferrer-Marin F, Liu ZJ, Gutti R, Sola-Visner M. Neonatal thrombocytopenia and megakaryocytopoiesis. Semin Hematol 2011; 47:281-8. [PMID: 20620440 DOI: 10.1053/j.seminhematol.2010.04.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Thrombocytopenia is common among sick neonates, affecting 20% to 35% of all patients admitted to the neonatal intensive care unit (NICU). While most cases of neonatal thrombocytopenia are mild or moderate and resolve within 7 to 14 days with appropriate therapy, 2.5% to 5% of NICU patients develop severe thrombocytopenia, sometimes lasting for several weeks and requiring >20 platelet transfusions. The availability of thrombopoietic agents offers the possibility of decreasing the number of platelet transfusions and potentially improving the outcomes of these infants. However, adding thrombopoietin (TPO) mimetics to the therapeutic armamentarium of neonatologists will require careful attention to the substantial developmental differences between neonates and adults in the process of megakaryocytopoiesis and in their responses to TPO. Taken together, the available data suggest that TPO mimetics will stimulate platelet production in neonates, but might do so through different mechanisms and at different doses than those established for adults. In addition, the specific groups of thrombocytopenic neonates most likely to benefit from therapy with TPO mimetics need to be defined, and the potential nonhematological effects of these agents on the developing organism need to be considered. This review summarizes our current understanding of neonatal megakaryocytopoiesis, and examines in detail the developmental factors relevant to the potential use of TPO mimetics in neonates.
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Affiliation(s)
- Francisca Ferrer-Marin
- Division of Newborn Medicine, Children's Hospital Boston and Harvard Medical School, Boston, MA 02115, USA
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Sallmon H, Gutti RK, Ferrer-Marin F, Liu ZJ, Sola-Visner MC. Increasing platelets without transfusion: is it time to introduce novel thrombopoietic agents in neonatal care? J Perinatol 2010; 30:765-9. [PMID: 20410910 DOI: 10.1038/jp.2010.50] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Food and Drug Administration recently approved two novel thrombopoiesis-stimulating agents, Romiplostim (AMG-531, Nplate) and Eltrombopag (Promacta), for the treatment of adults with immune thrombocytopenic purpura. For physicians taking care of critically ill neonates, this offers the opportunity of decreasing platelet transfusions and potentially improving the outcomes of neonates with severe and prolonged thrombocytopenia. However, several developmental factors need to be taken into consideration. First, the population of thrombocytopenic neonates likely to benefit from these agents needs to be carefully selected. Second, the mechanisms underlying neonatal and adult thrombocytopenia differ from each other and are incompletely understood, and pre-clinical evidence suggests that the response of neonates to thrombopoietic factors might be different from that of adults. Finally, the potential non-hematopoietic effects of thrombopoietin have not been well established. Here, we will discuss these issues in detail, and will highlight the critical developmental differences between neonates and adults that need to be considered as we think about introducing these agents into neonatal care.
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Affiliation(s)
- H Sallmon
- Division of Newborn Medicine, Children's Hospital Boston and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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Hu Z, Slayton WB, Rimsza LM, Bailey M, Sallmon H, Sola-Visner MC. Differences between newborn and adult mice in their response to immune thrombocytopenia. Neonatology 2010; 98:100-8. [PMID: 20134184 PMCID: PMC2914362 DOI: 10.1159/000280413] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 08/18/2009] [Indexed: 11/19/2022]
Abstract
BACKGROUND Sick neonates frequently develop severe thrombocytopenia. OBJECTIVE AND METHODS In order to test the ability of fetal mice to increase their megakaryocyte size and ploidy in response to thrombocytopenia, we injected an antiplatelet antibody (MWReg30) into pregnant mice daily for 7 days, and into nonpregnant adult mice to serve as controls. After that time, platelet counts were obtained and megakaryocytes in the bone marrow, liver, and spleen were stained with anti-von Willebrand factor antibody, individually measured, and quantified. RESULTS Our study demonstrated that megakaryocytopoiesis in newborn mice shares many features of human fetal/neonatal megakaryocytopoiesis, including the small size of megakaryocytes. In response to thrombocytopenia, adult mice increased megakaryocyte volume and concentration, primarily in the spleen. Newborn mice, in contrast, increased the megakaryocyte concentration in the spleen, but exhibited no increase in megakaryocyte volume in any of the organs studied. In fact, the megakaryocyte mass was significantly lower in the bone marrow of thrombocytopenic neonates than in age-matched controls. CONCLUSIONS We concluded that fetuses have a limited ability to increase their megakaryocyte mass in response to consumptive thrombocytopenia, compared to adult mice. These observations provide further evidence for the existence of biological differences between fetal/neonatal and adult megakaryocytopoiesis.
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Affiliation(s)
- Zhongbo Hu
- Department of Pediatrics, University of Florida, Gainesville, FL, USA
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Serum thrombopoietin level and thrombocytopenia during the neonatal period in infants with Down's syndrome. J Perinatol 2010; 30:98-102. [PMID: 19675574 DOI: 10.1038/jp.2009.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The pathogenesis of thrombocytopenia during the neonatal period in Down's syndrome (DS) infants remains unclear. OBJECTIVE To elucidate kinetic changes of serum thrombopoietin (TPO) level and platelet count, and their correlation in DS neonates. STUDY DESIGN Twelve DS infants (male/female: 7/5, term/late preterm: 10/2) born between 1997 and 2007 were included. Blood samples were serially collected during the neonatal period and serum TPO levels were determined in 44 sera using an enzyme-linked immunosorbent assay. RESULTS Thrombocytopenia <150 x 10(9) per liter was observed in seven (58%) patients. In 12 DS patients, the median TPO value showed 2.86 fmol ml(-1) on day 0, rose to 4.64 fmol ml(-1) on day 2, and thereafter decreased to 4.30 fmol ml(-1) on day 5, 2.40 fmol ml(-1) on days 11-15, and 1.75 fmol ml(-1) on days 28-30. This kinetics parallels that in historical non-DS controls. In 35 pair sample analysis from 11 patients without transient myeloproliferative disease, TPO level inversely correlated with platelet count (r=-0.38, P=0.023). However, there was no significant difference in TPO concentrations between thrombocytopenic and non-thrombocytopenic DS individuals. CONCLUSIONS This is the first study to describe the relationship between TPO level and platelet count in neonates with DS. Median TPO levels and their kinetic changes in DS neonates are comparable to those in non-DS controls. In contrast to earlier findings in several studies showing higher TPO concentrations in thrombocytopenic non-DS newborns than those in non-thrombocytopenic counterparts, the response of the TPO system to thrombocytopenia in DS during the neonatal period seems suboptimal.
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Sola-Visner M, Sallmon H, Brown R. New insights into the mechanisms of nonimmune thrombocytopenia in neonates. Semin Perinatol 2009; 33:43-51. [PMID: 19167581 PMCID: PMC2674325 DOI: 10.1053/j.semperi.2008.10.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Thrombocytopenia affects up to 35% of all patients admitted to the neonatal intensive care unit. The causes of thrombocytopenia in neonates are very diverse and include immune and nonimmune disorders. Most cases of thrombocytopenia encountered in the neonatal intensive care unit are nonimmune, and these will constitute the focus of this review. Specifically, we first discuss the biological differences between neonatal and adult megakaryocytopoiesis, which contribute to explain the vulnerability of neonates to develop thrombocytopenia. Next, we review new diagnostic tools that have allowed for a better evaluation of platelet production in neonates, without having to obtain a bone marrow sample. Finally, we summarize our current understanding of the mechanisms underlying the thrombocytopenia in several common neonatal conditions, such as chronic intrauterine hypoxia, sepsis and necrotizing enterocolitis, and viral infections. A better understanding of the mechanisms underlying these varieties of thrombocytopenia is critical to develop disease-specific treatment protocols and to begin to entertain the possibility of using novel thrombopoietic growth factors to treat selected neonates with severe thrombocytopenia.
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Affiliation(s)
- Martha Sola-Visner
- Division of Newborn Medicine, Children's Hospital Boston, Boston, MA 02115, USA.
| | - Hannes Sallmon
- Division of Newborn Medicine, Children’s Hospital Boston, Boston, MA,Department of Neonatology, Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Germany
| | - Rachel Brown
- Division of Newborn Medicine, Nationwide Children’s Hospital, Columbus, OH
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Brown RE, Rimsza LM, Pastos K, Young L, Saxonhouse MA, Bailey M, Lawrence RM, Sola-Visner MC. Effects of sepsis on neonatal thrombopoiesis. Pediatr Res 2008; 64:399-404. [PMID: 18552713 DOI: 10.1203/pdr.0b013e318181ad49] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We serially evaluated the effects of sepsis and/or necrotizing enterocolitis (NEC) on neonatal thrombopoiesis, using a panel of tests that included platelet counts, thrombopoietin concentrations (Tpo), circulating megakaryocyte progenitor concentrations (CMPs), and reticulated platelets (RPs). Variables analyzed included sepsis type, time after onset of sepsis, platelet counts, and gestational (GA) and postconceptional ages (PCA). Twenty neonates were enrolled. Ten had Gram-negative, six had Gram-positive, and four had presumed sepsis. Four neonates had NEC stage II or higher, and six developed thrombocytopenia. Overall, septic neonates had significantly elevated Tpo concentrations and circulating megakaryocyte progenitors. The highest Tpo levels were associated with Gram-negative or presumed sepsis. RP percentages were increased only in neonates with low platelet counts, while RP counts (RP% x platelet count) were elevated in neonates with high platelet counts. Our findings suggest that septic neonates up-regulate Tpo production, leading to increased megakaryocytopoiesis and platelet release, although the degree of upregulation is moderate. The changes in RP% and RP count most likely reflect increased thrombopoiesis with variable degrees of platelet consumption. In addition, our findings suggest that different factors, likely including level of illness and/or specific platelet or bacterial products, can down-regulate the magnitude of the thrombopoietic response.
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Affiliation(s)
- Rachel E Brown
- Department of Pediatrics, University of Florida, Gainesville, Florida 32610, USA.
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Sola-Visner MC, Christensen RD, Hutson AD, Rimsza LM. Megakaryocyte size and concentration in the bone marrow of thrombocytopenic and nonthrombocytopenic neonates. Pediatr Res 2007; 61:479-84. [PMID: 17515875 DOI: 10.1203/pdr.0b013e3180332c18] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Thrombocytopenia is frequent among sick neonates, but little is known about its underlying mechanisms. It is known, however, that neonatal megakaryocytes are smaller and of lower ploidy than their adult counterparts and that smaller megakaryocytes produce fewer platelets than larger, more polyploid, megakaryocytes. We hypothesized that neonatal megakaryocytes would not increase their size in response to thrombocytopenia, thus limiting the ability of neonates to mount a response. To test this, we obtained marrow specimens from thrombocytopenic and nonthrombocytopenic neonates and adults. Megakaryocytes were immunohistochemically stained, quantified using an eyepiece reticle, and measured using an image analysis system with incorporated electronic micrometer. We found that, after adjusting for differences in cellularity, neonates and adults had similar megakaryocyte concentrations. When samples from the same sources were compared (tibial clot and vertebral body sections in neonates, iliac crest biopsies in adults), there were also no differences in megakaryocyte concentration between thrombocytopenic and nonthrombocytopenic subjects. The megakaryocyte diameter, however, was greater in adults than in neonates (19.4 +/- 3.0 versus 15.3 +/- 1.7 microm, p<0.0001). Thrombocytopenic adults also had a higher proportion of large megakaryocytes than nonthrombocytopenic adults (p<0.001). This was not observed among thrombocytopenic neonates, suggesting a developmental limitation in their ability to increase megakaryocyte size.
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Israels SJ. Platelet Function in the Newborn. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50784-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Roberts IA, Murray NA. Thrombocytopenia in the Newborn. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50814-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Saxonhouse MA, Rimsza LM, Stevens G, Jouei N, Christensen RD, Sola MC. Effects of hypoxia on megakaryocyte progenitors obtained from the umbilical cord blood of term and preterm neonates. Neonatology 2005; 89:104-8. [PMID: 16192692 DOI: 10.1159/000088561] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Accepted: 07/11/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND Placental insufficiency is associated with early-onset thrombocytopenia in preterm neonates. Prior studies demonstrated a reduction in circulating megakaryocyte (Mk) progenitors, suggesting decreased platelet production. We hypothesized that decreased Mk production is the result of a direct inhibitory effect of hypoxia on the proliferation of Mk progenitors, or a hypoxia-induced change in the fetal hematopoietic environment. OBJECTIVE To test the effects of hypoxia on the clonogenic maturation of Mk progenitors obtained from term and preterm cord blood CD34(pos) cells, either cultured alone or in conjunction with CD34(neg) light density mononuclear cells (LDMCs). METHODS CD34(pos) cells and CD34(neg) LDMCs were isolated from the cord blood of term and preterm deliveries, and mobilized peripheral blood CD34(pos) cells were obtained from healthy adults. CD34(pos) cells were then cultured alone or co-cultured with CD34(neg) LDMCs in a semisolid, serum-free media containing rTpo, IL-3, and IL-6. Cultures were exposed to 20%, 5%, or 1% oxygen for 10-12 days. Mk colonies were then quantified following immunohistochemical staining. RESULTS Pure CD34(pos) cells from preterm (n = 5) and term (n = 5) neonates and from adults (n = 4) generated similar numbers of Mk colonies in all three oxygen concentrations. However, the number of Mk colonies in preterm co-cultures was progressively lower with decreasing O(2) concentrations. CONCLUSIONS Hypoxia did not appear to directly inhibit colony formation of Mk progenitors from preterm and term cord blood CD34(pos) cells. However, co-culture studies showed a decrease in Mk colony formation with hypoxia, suggesting an indirect inhibitory effect of hypoxia on Mk clonogenic maturation mediated by non-progenitor cells in the hematopoietic microenvironment.
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Abstract
This review summarizes current data on the pathomechanisms and clinical aspects of primary and secondary thrombocytosis in childhood. Primary thrombocytosis is extremely rare in childhood, mostly diagnosed at the beginning of the second decade of life. As in adults, the criteria of the Polycythemia Vera Group are appropriate to diagnose primary thrombocytosis. The pathomechansims of non-familial forms are complex and include spontaneous formation of megakaryopoietic progenitors and increased sensitivity to thrombopoietin (Tpo). Familial forms can be caused by mutations in Tpo or Tpo receptor (c-mpl) genes. These mutations result in overexpression of Tpo, sustained intracellular signalling or disturbed regulation of circulating Tpo. Treatment of primary thrombocytosis is not recommended if platelet counts are <1500/nl and bleeding or thrombosis did not occur in patient's history. In severe cases, decision on treatment should weigh potential risks of treatment options (hydroxyurea, anagrelide) against expected benefits for preventing thrombosis or haemorrhage. Secondary thrombocytosis is frequent in children, in particular in the first decade of life. Hepatic Tpo production is stimulated in acute response reaction to a variety of disorders. Thrombosis prophylaxis is not required, even at platelet counts >1000/nl, except for cases with additional prothrombotic risk factors.
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Affiliation(s)
- Christof Dame
- Department of Neonatology, Charité- University Medicine Berlin, Campus Virchow-Klinikum, Berlin, Germany.
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Matsubara K, Nigami H, Harigaya H, Hirata T, Nozaki H, Fukaya T, Baba K, Miyazaki H. Thrombopoietin in the Cerebrospinal Fluid of Patients with Aseptic and Bacterial Meningitis. J Interferon Cytokine Res 2005; 25:220-6. [PMID: 15812248 DOI: 10.1089/jir.2005.25.220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Despite the recent evidence of the localization of thrombopoietin (TPO) and its receptor in the central nervous system (CNS), TPO protein concentrations in the cerebrospinal fluid (CSF) remained to be clarified. We previously reported that serum TPO is increased in children with meningitis. To determine changes in TPO concentrations in the CSF by meningitis and to explore the relationship between serum and CSF TPO concentrations, we measured TPO concentrations in 110 CSF samples and 33 serum/CSF pairs from 11 bacterial meningitis, 49 aseptic meningitis, and 50 nonmeningitis children. In only 12% (13 of 110) of CSF samples (0 bacterial meningitis, 8 aseptic meningitis, and 5 controls), TPO concentrations could be determined (24.1 +/- 29.0 pg/ml). CSF TPO concentrations did not significantly differ among the three groups and did not correlate with age. TPO concentrations in all serum samples were detectable, and mean concentrations in bacterial meningitis (510.6 +/- 237.0 pg/ml) were significantly higher than those in aseptic meningitis (136.6 +/- 71.6, p < 0.01) and controls (181.3 +/- 88.3, p < 0.01). These findings suggest that TPO is not produced in the CNS of patients with meningitis and that TPO did not cross the blood-brain barrier even during meningeal infection.
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Affiliation(s)
- Kousaku Matsubara
- Department of Pediatrics, Nishi-Kobe Medical Center, 5-7-1 Kojidai, Nishi-ku, Kobe 651-2273, Japan.
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Dodig S, Raos M, Kovac K, Nogalo B, Benko B, Glojnaric I, Dodig M, Cepelak I. Thrombopoietin and Interleukin-6 in Children with Pneumonia-Associated Thrombocytosis. Arch Med Res 2005; 36:124-8. [PMID: 15847944 DOI: 10.1016/j.arcmed.2004.12.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Accepted: 11/24/2004] [Indexed: 11/22/2022]
Abstract
BACKGROUND The aim of this study was to investigate why some, but not all, children develop thrombocytosis during the course of pneumonia. METHODS The retrospective study included 40 healthy children and 75 children with pneumonia: 17 patients with platelet count within the reference values, i.e., platelet count </=450 x 10(9)/L, and 58 with thrombocytosis >450 x 10(9)/L. Erythrocyte sedimentation rate, leukocyte and platelet counts, and concentrations of hemoglobin, C-reactive protein, interleukin-6 and thrombopoietin were determined in the blood of patients and control groups of children. RESULTS Patients with thrombocytosis were slightly younger (3.0 +/- 1.8 years and median 2.5 years, respectively) than patients with normal platelet count (3.8 +/- 2.4 years and median 4 years, respectively). Additionally, according to clinical and radiological findings, pneumonia in children with thrombocytosis had a more severe and protracted course. Serum thrombopoietin concentrations were found to be 91.2 +/- 41.7 ng/L (range: 14.3-166.7 ng/L) in patients with normal platelet count (313 +/- 70 x 10(9)/L, range: 206-428 x 10(9)/L). In patients with thrombocytosis (581 +/- 131 x 10(9)/L, range: 450-830 x 10(9)/L) serum thrombopoietin ranged from 63.6 to 1115.9 ng/L (526.6 +/- 268.4 ng/L). In these patients both concentration of hemoglobin (114 +/- 12 g/L) and iron (4.3 +/- 1.3 micromol/L) significantly decreased as compared with the control group. CONCLUSIONS Study results suggested the possible development of reactive thrombocytosis in children with pneumonia. As platelets are involved in inflammatory reaction, reactive thrombocytosis might be part of the mechanism of defense. Reactive thrombocytosis may develop as a sequel of either anemia or inflammatory reaction (or both).
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Affiliation(s)
- Slavica Dodig
- Special Hospital for Respiratory Diseases in Children and Adolescents, School of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia.
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Nakayama H, Ihara K, Hikino S, Yamamoto J, Nagatomo T, Takemoto M, Hara T. Thrombocytosis in preterm infants: a possible involvement of thrombopoietin receptor gene expression. J Mol Med (Berl) 2005; 83:316-20. [PMID: 15647951 DOI: 10.1007/s00109-004-0619-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2004] [Accepted: 11/01/2004] [Indexed: 11/29/2022]
Abstract
Transient thrombocytosis is commonly observed in preterm infants after birth, but its physiological mechanism is still unknown. To understand the mechanism of the transient thrombocytosis in preterm infants we firstly evaluated a correlation between platelet counts and thrombopoietin (TPO) levels in preterm infants and next c-mpl mRNA levels on platelets in healthy preterm infants longitudinally during a half-year of life. The mean platelet counts in 45 very low birth weight infants (mean gestational age 27.4+/-1.8 weeks, mean birth weight 1047+/-249 g) was 230+/-71x10(9)/l just after birth and thereafter gradually increased to 579+/-178x10(9)/l by 5 weeks of age. The platelet counts continued this level for about next 8 weeks. Serum TPO levels soon after birth and at 1 month of age were significantly higher than those at the age of 2-6 months. There was a significant negative correlation between platelet counts and serum TPO values. The c-mpl expression levels on platelets at birth and at 1 month of age tended to be lower than those on platelets from adults, and the c-mpl levels gradually increased through 6 months of age, although they were still lower than those of adults. Our results suggest that low expression of TPO receptor on platelets until 1 month after birth cause a decreased TPO clearance and keep a high level of free TPO in blood, thereby promoting platelet production from megakaryocytes or their progenitors in bone marrow, resulting in the subsequent thrombocytosis in preterm infants.
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Affiliation(s)
- Hideki Nakayama
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, 812-8582 Fukuoka, Japan
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Abstract
Thrombocytopenia occurs in up to a third of preterm neonates admitted to intensive care units. In these babies, thrombocytopenia typically presents in one of two patterns: early-onset thrombocytopenia occurring within 72 h of birth and late-onset thrombocytopenia which develops after 72 h. Early-onset thrombocytopenia is most commonly caused by disorders associated with placental insufficiency (e.g. maternal hypertension), is mild-moderate, self-limiting and requires no treatment; it is caused by reduced platelet production. Late-onset thrombocytopenia is usually due to bacterial sepsis or necrotising enterocolitis; it is often severe (platelets <50 x 10(9)/l), prolonged and requires treatment with platelet transfusions. In term babies, neonatal thrombocytopenia is usually severe and most commonly caused by bacterial sepsis, perinatal asphyxia or neonatal alloimmune thrombocytopenia. There is a lack of evidence-based guidelines for treatment of neonatal thrombocytopenia. The most important future developments will depend upon studies aimed at determining optimal platelet transfusion schedules for term and preterm neonates.
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Affiliation(s)
- Subarna Chakravorty
- Department of Haematology, Great Ormond Street Hospital, Great Ormond Street, London WC1N 3JH, UK
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Saxonhouse MA, Christensen RD, Walker DM, Hutson AD, Sola MC. The concentration of circulating megakaryocyte progenitors in preterm neonates is a function of post-conceptional age. Early Hum Dev 2004; 78:119-24. [PMID: 15223116 DOI: 10.1016/j.earlhumdev.2004.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/31/2004] [Indexed: 11/26/2022]
Abstract
Circulating megakaryocyte (Mk) progenitors have been used as a measure of megakaryocytopoiesis in neonates. Prior studies have shown a gestational age-dependent decrease in their concentration, but it is unclear how this process continues after birth in preterm neonates. To answer this question, we quantified the Mk progenitors in the blood of 42 neonates of varying post-conceptional ages (gestational age+days of life). We found an inverse relationship between concentration of circulating Mk progenitors and post-conceptional age (r=-0.54, p=0.0002).
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Affiliation(s)
- Matthew A Saxonhouse
- Division of Neonatology, Department of Pediatrics, University of Florida, College of Medicine, P.O. Box 100296, Gainesville, FL 32610-0296, USA.
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Abstract
Thrombocytopenia is one of the most common hematologic problems in the neonatal intensive care unit (NICU). Despite its prevalence,several basic pathophysiologic questions remain unanswered. For instance, there is a lack of evidence-based guidelines for treatment,and the kinetic mechanisms (decreased platelet production,increased platelet consumption, or sequestration) responsible for most varieties of neonatal thrombocytopenia are not well defined.Moreover, a clear correlation between degree of thrombocytopenia and the resulting bleeding risk has not been demonstrated, and no transfusion-trigger studies have been conducted in neonates. As a consequence of these deficiencies in knowledge, there is great variability in platelet transfusion practices among NICUs. This article presents an overview of the evaluation of a neonate with severe thrombocytopenia and a review of current and projected therapeutic options.
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Affiliation(s)
- Martha C Sola
- Division of Neonatology, Department of Pediatrics, University of Florida College of Medicine, 1600 SW Archer Road, Gainesville, FL 32610, USA.
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Abstract
Necrotizing enterocolitis (NEC), the most common surgical emergency in newborns, remains a therapeutic challenge for clinicians. The hematological manifestations associated with NEC were first described 25 years ago. This review discusses current knowledge of the pathophysiology involved in disturbances in megakaryocytopoiesis, coagulation, leukopoiesis, and erythropoiesis that accompany the clinical entity NEC. The discussion includes current understanding of and potential strategies for treating the hematopoietic disturbances that occur secondary to NEC.
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Affiliation(s)
- Pamela J Kling
- Department of Pediatrics, University of Wisconsin, 6 Center Meriter Hospital, 202 South Park Street, Madison, WI 53715, USA
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Abstract
Neonatal thrombocytopenia is a common clinical problem. Thrombocytopenia presenting in the first 72 hours of life is usually secondary to placental insufficiency and caused by reduced platelet production; fortunately most episodes are mild or moderate and resolve spontaneously. Thrombocytopenia presenting after 72 hours of age is usually secondary to sepsis or necrotising enterocolitis and is usually more severe and prolonged. Platelet transfusion remains the only treatment. There is a need for trials to define the safe lower limit for platelet count and which neonates will benefit from treatment.
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Affiliation(s)
- I Roberts
- Imperial College, Hammersmith Campus, London W12 0NN, UK.
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Cremer M, Dame C, Schaeffer HJ, Giers G, Bartmann P, Bald R. Longitudinal thrombopoietin plasma concentrations in fetuses with alloimmune thrombocytopenia treated with intrauterine PLT transfusions. Transfusion 2003; 43:1216-22. [PMID: 12919423 DOI: 10.1046/j.1537-2995.2003.00489.x] [Citation(s) in RCA: 10] [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
BACKGROUND The purpose of this study was to describe longitudinal thrombopoietin (TPO) plasma concentrations in fetuses with fetomaternal alloimmune thrombocytopenia (FMAIT). STUDY DESIGN AND METHODS Group 1 was the control group, 8 fetuses with normal hematopoiesis. Group 2 consisted of 4 nonthrombocytopenic fetuses with fetomaternal human PLT antigen incompatibility. Group 3 consisted of 14 fetuses with prenatal-diagnosed severe FMAIT owing to human PLT antigen-1a incompatibility. Fetal PLT counts, MoAb-specific immobilization of PLT antigen score, and TPO plasma concentrations were measured in a total number of 94 serial samples taken by cordocentesis before intrauterine PLT transfusion. RESULTS Normal fetal TPO plasma concentrations ranged between 15 and 119 pg per mL (Group 1 median, 67 pg/mL). In fetuses with risk of FMAIT but normal PLT counts, TPO concentrations were normal (Group 2 median, 72 pg/mL; range, <15-158 pg/mL). In FMAIT with thrombocytopenia, the median TPO concentration was significantly higher than in Groups 1 and 2 (Group 3 median, 172 pg/mL; range, 15-623 pg/mL; p < 0.001). In the longitudinal analysis, TPO concentrations remained constant (n = 8), peaked only transiently (n = 3), or increased at the end of gestation (n = 3). Elevated TPO concentrations (592 and 623 pg/mL) were detected in one patient, who already had intracranial hemorrhage in utero. CONCLUSION TPO concentrations are normal or slightly elevated in FMAIT. Further clinical information can be provided by the longitudinal analysis of TPO concentrations in severe FMAIT.
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Affiliation(s)
- Malte Cremer
- Department of Neonatology, University of Bonn, Bonn, Germany.
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Murray NA. Evaluation and treatment of thrombocytopenia in the neonatal intensive care unit. ACTA PAEDIATRICA (OSLO, NORWAY : 1992). SUPPLEMENT 2003; 91:74-81. [PMID: 12477267 DOI: 10.1111/j.1651-2227.2002.tb02908.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
UNLABELLED Phlebotomy-induced anaemia excepted, thrombocytopenia is the most common haematological abnormality in neonatal intensive care unit (NICU) patients. Roughly one-quarter of all NICU patients and half of all sick preterm neonates develop thrombocytopenia. Whereas a large number of varied precipitating conditions has been identified, early-onset thrombocytopenia (<72 h) is most commonly associated with fetomaternal conditions complicated by placental insufficiency and/or fetal hypoxia, e.g. maternal pre-eclampsia and fetal intrauterine growth restriction. The resulting neonatal thrombocytopenia is usually mild to moderate, resolves spontaneously and requires no specific therapy. Deviation from this pattern of thrombocytopenia suggests the presence of more significant precipitating conditions. The most important of these are the immune thrombocytopenias, and every NICU should develop investigation and treatment protocols to manage these cases promptly and avoid unnecessary risk of haemorrhage. In contrast, late-onset thrombocytopenia (>72 h) is almost always associated with sepsis or necrotizing enterocolitis and the associated thrombocytopenia is severe, prolonged and often requires treatment by platelet transfusion. Unfortunately, evidence-based guidelines for platelet transfusion therapy in NICU patients are currently unavailable, making it difficult to define widely accepted thresholds for transfusion and leading to a significant variation in transfusion practice between centres. CONCLUSION While improving this situation remains a pressing need, the growing evidence that impaired megakaryocytopoiesis and platelet production are major contributors to many neonatal thrombocytopenias suggests that recombinant haemopoietic growth factors, including thrombopoietin and interleukin-11, may be useful future therapies to ameliorate neonatal thrombocytopenia.
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Affiliation(s)
- N A Murray
- Imperial College, Faculty of Medicine, Hammersmith Hospital, London, UK
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Sola MC, Rimsza LM. Mechanisms underlying thrombocytopenia in the neonatal intensive care unit. ACTA PAEDIATRICA (OSLO, NORWAY : 1992). SUPPLEMENT 2003; 91:66-73. [PMID: 12477266 DOI: 10.1111/j.1651-2227.2002.tb02907.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
UNLABELLED Thrombocytopenia is one of the most common hematological problems among neonates in the neonatal intensive care unit (NICU), but in the majority of cases the kinetic mechanism responsible is unclear. This review focuses on both traditional and innovative methods used to evaluate the mechanisms responsible for thrombocytopenia in neonates, and analyzes the data generated from those methods. CONCLUSION Results of studies using new methods for evaluating thrombocytopenia, coupled with recent descriptions of marrow megakaryocyte mass, suggest that decreased platelet production complicates most cases of thrombocytopenia among neonates in the NICU.
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Affiliation(s)
- M C Sola
- Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
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Abstract
Thrombocytopenia remains a common problem in sick newborns. A quarter of all neonates admitted to neonatal intensive care units develop thrombocytopenia, and in 20% of episodes the thrombocytopenia is severe (platelets <50 x 10(9)/L). Practical and clinically relevant classifications of neonatal thrombocytopenia have now been developed which, by highlighting the principal conditions precipitating severe thrombocytopenia (eg, sepsis, necrotizing enterocolitis, perinatal asphyxia, and the immune thrombocytopenias), aid the practicing neonatologist. Recent reviews demonstrate that many neonates with severe thrombocytopenia receive repeated platelet transfusions, although evidence of their clinical benefit is lacking, and there exists a significant variation in platelet transfusion practice between centers. These facts support the need for the development of evidence-based protocols for platelet transfusion in the newborn and stimulate continued interest in the potential of hemopoietic growth factors (, thrombopoietin and interleukin-11) to prevent or treat neonatal thrombocytopenia.
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Affiliation(s)
- Irene A G Roberts
- Pediatric Hematology, Imperial College, Faculty of Medicine, Hammersmith Hospital, London, United Kingdom.
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Abstract
PURPOSE To investigate the factors affecting thrombopoietin (TPO) levels in preterm infants and to determine if TPO levels differ in infants born to mothers with preeclampsia and those infants with culture-proven sepsis. METHODS Serial serum samples (N = 95) were obtained from 27 infants less than 33 weeks' gestation. Samples were analyzed for TPO using enzyme-linked immunosorbent assay. All samples had an accompanying complete blood count. Analysis of variance with post hoc analysis by least significant difference test, Mann-Whitney test, or chi2 was used to compare groups, as appropriate. Forward, stepwise linear regression was used to account for potential confounding variables. Data are expressed as mean +/- SD. RESULTS TPO levels were not significantly correlated with the absolute platelet counts (R = -0.04, P = 0.69). TPO levels were significantly correlated with gestational age (R= 0.50, P < 0.001) when the platelet count was less than 150,000/mm3. TPO levels were significantly elevated in infants with platelets less than 150,000/mm3 born to mothers with preeclampsia compared with infants with sepsis (1184 +/- 98 vs. 579 +/- 363 pg/mL, P < 0.01). After adjusting for confounding variables using multivariate analysis (model: r2 = 0.43, P < 0.01), gestational age (r2 = 0.26) and preeclampsia (r2 = 0.03) remained significantly associated with TPO levels, whereas sepsis did not contribute to the variability of TPO. CONCLUSIONS TPO response of infants with platelets less than 150,000/mm3 is dependent on gestational age. Infants with thrombocytopenia associated with preeclampsia have increased circulating levels of TPO. Infants with thrombocytopenia secondary to sepsis do not show an increase in TPO, but this appears to be an effect of low gestational age.
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Affiliation(s)
- David A Paul
- Department of Pediatrics, Section of Neonatology, Christiana Care Health Services, Newark, DE 19718, USA.
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Matsubara K, Kato T, Miyazaki H. Thrombopoietin in human milk. Int J Hematol 2002; 75:109-10. [PMID: 11843283 DOI: 10.1007/bf02981991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Matsubara K, Baba K, Nigami H, Harigaya H, Ishiguro A, Kato T, Miyazaki H. Early elevation of serum thrombopoietin levels and subsequent thrombocytosis in healthy preterm infants. Br J Haematol 2001; 115:963-8. [PMID: 11843834 DOI: 10.1046/j.1365-2141.2001.03183.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To verify pathophysiological mechanisms underlying thrombocytosis in low-birth-weight (LBW) preterm babies, we evaluated kinetic changes in platelet counts and thrombopoietic cytokines including thrombopoietin (TPO), interleukin 6 (IL-6) and IL-11 in 24 uncomplicated preterm infants. Platelet counts in cord blood (CB) (265 +/- 64 x 10(9)/l) were similar to adult levels, increased by d 14 (473 +/- 140 x 10(9)/l), and then remained fairly constant. Thrombocytosis (> 500 x 10(9)/l) was observed in 9/24 (38%) subjects. Mean TPO level in CB was 5.11 +/- 1.51 fmol/ml, peaked at d 2 (7.64 +/- 3.28 fmol/ml), decreased at d 5 (3.93 +/- 1.67 fmol/ml), and thereafter kept fairly constant during the remaining neonatal period. Compared with term infants, mean TPO levels of preterm infants in CB and at d 2 were significantly higher (P < 0.01). There was an inverse correlation between platelet counts and TPO levels (r = 0.45, P < 0.001, n = 88). Preterm neonates with thrombocytosis had significantly higher TPO values in CB than those without thrombocytosis (P < 0.05). There was no significant relationship between platelet counts and IL-6. IL-11 was not detectable. These results suggest that an early elevation of serum TPO levels is related to the subsequent thrombocytosis in LBW preterm infants.
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Affiliation(s)
- K Matsubara
- Department of Paediatrics, Nishi-Kobe Medical Centre, 5-7-1 Kojidai, Nishi-ku, Kobe 651-2273, Japan.
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Bornstein R, García-Vela J, Gilsanz F, Auray C, Calés C. Cord blood megakaryocytes do not complete maturation, as indicated by impaired establishment of endomitosis and low expression of G1/S cyclins upon thrombopoietin-induced differentiation. Br J Haematol 2001; 114:458-65. [PMID: 11529870 DOI: 10.1046/j.1365-2141.2001.02954.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cord blood (CB) has successfully been used as a stem cell source for haemopoietic reconstitution. However, a significant delay in platelet engraftment is consistently found in CB versus adult peripheral blood (PB) or bone marrow transplants. We sought to determine whether or not CB megakaryocytes have reached terminal maturation and, hence, full thrombopoietic potential. A comparative analysis of megakaryocytes cultured from either CB or PB progenitors in the presence of thrombopoietin (TPO) showed a similar differentiation response, although proliferation was 2.4 times higher in CB than in PB cells. Importantly, the TPO-induced ploidy level was notably different: whereas 82.7% of CB megakaryocytes remained diploid (2N) at the end of the culture, more than 50% of PB megakaryocytes had reached a DNA content equal to or higher than 4N. Western blot and flow cytometry analyses revealed that only polyploid PB megakaryocytes expressed cyclins E, A and B, whereas cyclin D3 was detected in both fetal and adult megakaryocytic nuclei. These data suggest that establishment of endomitotic cycles is impaired in CB megakaryocytes, associated with a differential regulation of G1/S cell cycle factors. We believe that the relative immaturity of fetal megakaryocytes could be a contributing factor to the delayed platelet engraftment in cord blood transplantation.
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Affiliation(s)
- R Bornstein
- Madrid Cord Blood Bank, Hospital Universitario 12 de Octubre, Madrid, Spain
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Del Vecchio A, Sola MC, Theriaque DW, Hutson AD, Kao KJ, Wright D, Garcia MG, Pollock BH, Christensen RD. Platelet transfusions in the neonatal intensive care unit:factors predicting which patients will require multiple transfusions. Transfusion 2001; 41:803-8. [PMID: 11399824 DOI: 10.1046/j.1537-2995.2001.41060803.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Previous studies suggest that recombinant thrombopoietin (rTPO) will increase platelet production in thrombocytopenic neonates. However, the target populations of neonates most likely to benefit should be defined. Studies suggest that rTPO will not elevate the platelet count until 5 days after the start of treatment. Therefore, the neonates who might benefit from rTPO are those who will require multiple platelet transfusions for more than 5 days. This study was designed to find means of prospectively identifying these patients. STUDY DESIGN AND METHODS A historic cohort study of all patients in the neonatal intensive care unit (NICU) at the University of Florida who received platelet transfusions from January 1, 1997, through December 31, 1998, was conducted. RESULTS Of the 1389 patients admitted to the NICU during the study period, 131 (9.4%) received platelet transfusions. Seventeen were treated with extracorporeal membrane oxygenation and were excluded from further analysis. Of the remaining 114 patients, 55 (48%) received one transfusion and 59 (52%) received more than one transfusion (21 had >4). None of the demographic factors examined predicted multiple platelet transfusions. However, two clinical conditions did; liver disease and renal insufficiency. Neonates who received one platelet transfusion had a relative risk of death 10.4 times that in neonates who received none (p = 0.0001). Neonates who received >4 platelet transfusions had a risk of death 29.9 times that in those who received no transfusions (p = 0.0001). CONCLUSION NICU patients with liver disease or renal insufficiency who receive one platelet transfusion are likely to receive additional transfusions. Therefore, these patients constitute a possible study population for a Phase I/II rTPO trial.
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Affiliation(s)
- A Del Vecchio
- Division of Neonatology, Department of Pediatrics, University of Florida, College of Medicine, Gainesville, Florida, USA
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Sola MC, Dame C, Christensen RD. Toward a rational use of recombinant thrombopoietin in the neonatal intensive care unit. J Pediatr Hematol Oncol 2001; 23:179-84. [PMID: 11305723 DOI: 10.1097/00043426-200103000-00013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- M C Sola
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, USA.
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50
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Roberts IA, Murray NA. Neonatal thrombocytopenia: new insights into pathogenesis and implications for clinical management. Curr Opin Pediatr 2001; 13:16-21. [PMID: 11176238 DOI: 10.1097/00008480-200102000-00003] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The healthy fetus has a platelet count of greater than 150 x 10(9)/L by the second trimester of pregnancy and only 2% of term infants are thrombocytopenic at birth. Severe thrombocytopenia (platelets < 50 x 10(9)/L) occurs in fewer than three per 1000 term infants, the most important cause being alloimmune thrombocytopenia. In contrast, in infants admitted to neonatal intensive care units, thrombocytopenia develops in 25% and in up to half of sick preterm infants. Recent evidence shows that these infants mostly have evidence of underlying impaired fetal megakaryocytopoiesis and platelet production following pregnancy complications characterized by placental insufficiency or fetal hypoxia. The mechanism of this is unknown. However, many neonatal complications exacerbate this thrombocytopenic potential and 20% of thrombocytopenias in neonatal intensive care unit patients are severe. Evidence-based guidelines for platelet transfusion therapy in these patients are yet to be defined, but as platelet underproduction underlies most neonatal thrombocytopenias, recombinant hemopoietic growth factors, including thrombopoietin and interkeukin-11, may be useful future therapies.
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Affiliation(s)
- I A Roberts
- Department of Paediatric Haematology, Imperial College School of Medicine, Hammersmith Hospital, London UK.
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