ObjectiveDespite lack of evidence supporting efficacy, prophylactic fresh frozen plasma and Octaplas transfusions may be administered to very preterm infants to reduce bleeding risk. International variation in plasma transfusion practices in neonatal intensive care units (NICUs) is poorly understood, therefore, we aimed to describe neonatal plasma transfusion practice in Europe.DesignProspective observational study.Setting64 NICUs in 22 European countries, with a 6-week study period per centre between September 2022 and August 2023.PatientsPreterm infants born below 32 weeks of gestational age.InterventionsAdmission to the NICU.Main outcome measuresPlasma transfusion prevalence, cumulative incidence, indications, transfusion volumes and infusion rates and adverse effects.ResultsA total of 92 of 1143 infants included (8.0%) received plasma during the study period, collectively receiving 177 transfusions. Overall prevalence was 0.3 plasma transfusion days per 100 admission days, and rates varied substantially across Europe. By day 28 of life, 13.5% (95% CI 10.0% to 16.9%) of infants received at least one plasma transfusion, accounted for competing risks of death or discharge. Transfusions were given for a broad range of indications, including active bleeding (29.4%), abnormal coagulation screen results (23.7%) and volume replacement/hypotension (21.5%). Transfusion volumes and infusion rates varied significantly; the most common volume was 15 mL/kg (range: 5–30 mL/kg) and the most common duration was 2 hours (range: 30 min to 6 hours).ConclusionsWe found wide variation in plasma transfusion practices in Europe, highlighting the need for evidence to inform neonatologists in daily practice and guidelines, in particular for non-bleeding indications.Trial registration numberISRCTN17267090.

Thrombocytopenia (defined as a platelet count <150×109/L) is a common condition in preterm neonates and may occur in 18-35% of all infants admitted to the Neonatal Intensive Care Unit (NICU). Neonatal platelet functionality in terms of reactivity is often described as reduced compared to adults, even in healthy, term neonates. However, this platelet "hyporeactivity" does not correspond to a global functional impairment of the normal delicately balanced neonatal hemostatic system. The extent to which neonatal thrombocytopenia and platelet hyporeactivity contribute to the bleeding risk in preterm neonates remains unknown. Prophylactic platelet transfusions are often administered to them to reduce the risk of bleeding. However, recent literature indicates that adopting a higher platelet transfusion threshold than a lower one results in significantly higher death rates or major bleeding and can be harmful. Although the mechanism by which this occurs is not entirely clear, a mismatch between adult transfused platelets and the neonatal hemostatic system, as well as volume overload, are speculated to be potentially involved. Therefore, future research should consider novel transfusion products that may be more suitable for premature neonates. Blood products derived from umbilical cord blood (UCB) are promising, as they might perfectly match neonatal blood features. Here, we discuss the current knowledge about UCB-derived products, focusing on UCB-derived platelet concentrates and their potential for future clinical application. We will discuss how they may overcome the potential risks of transfusing adult-derived platelets to premature infants while maintaining efficacy.

Background Platelet transfusions are given to preterm infants with severe thrombocytopenia aiming to prevent haemorrhage. The PlaNeT2/MATISSE trial revealed higher rates of mortality and/or major bleeding in preterm infants receiving prophylactic platelet transfusions at a platelet count threshold of 50 x 10(9)/L compared to 25 x 10(9)/L. The extent to which this evidence has been incorporated into clinical practice is unknown, thus we aimed to describe current neonatal platelet transfusion practices in Europe. Methods We performed a prospective observational study in 64 neonatal intensive care units across 22 European countries between September 2022 and August 2023. Outcome measures included observed transfusion prevalence rates (per country and overall, pooled using a random effects Poisson model), expected rates based on patient-mix (per country, estimated using logistic regression), cumulative incidence of receiving a transfusion by day 28 (with death and discharge considered as competing events), transfusion indications, volumes and infusion rates, platelet count triggers and increment, and adverse effects. Findings We included 1143 preterm infants, of whom 71 (6.2%, [71/1143]) collectively received 217 transfusions. Overall observed prevalence rate was 0.3 platelet transfusion days per 100 admission days. By day 28, 8.3% (95% CI: 5.5-11.1) of infants received a transfusion. Most transfusions were indicated for threshold (74.2%, [161/217]). Pre-transfusion platelet counts were above 25 x 10(9)/L in 33.1% [53/160] of these transfusions. There was significant variability in volume and duration. Interpretation The restrictive threshold of 25 x 10(9)/L is being integrated into clinical practice. Research is needed to explore existing variation and generate evidence for various aspects including optimal volumes and infusion rates.

Importance:Red blood cell (RBC) transfusions are frequently administered to preterm infants born before 32 weeks of gestation in the neonatal intensive care unit (NICU). Two randomized clinical trials (Effects of Transfusion Thresholds on Neurocognitive Outcomes of Extremely Low-Birth-Weight Infants [ETTNO] and Transfusion of Prematures [TOP]) found that liberal RBC transfusion thresholds are nonsuperior to restrictive thresholds, but the extent to which these results have been integrated into clinical practice since publication in 2020 is unknown. Objective:To describe neonatal RBC transfusion practice in Europe. Design, Setting, and Participants:This international prospective observational cohort study collected data between September 1, 2022, and August 31, 2023, with a 6-week observation period per center, from 64 NICUs in 22 European countries. Participants included 1143 preterm infants born before 32 weeks of gestation. Exposure:Admission to the NICU. Main Outcomes and Measures:Study outcome measures included RBC transfusion prevalence rates, cumulative incidence, indications, pretransfusion hemoglobin (Hb) levels, volumes, and transfusion rates, Hb increment, and adverse effects of RBC transfusion. Results:A total of 1143 preterm infants were included (641 male [56.1%]; median gestational age at birth, 28 weeks plus 2 days [IQR, 26 weeks plus 2 days to 30 weeks plus 2 days]; median birth weight, 1030 [IQR, 780-1350] g), of whom 396 received 1 or more RBC transfusions, totaling 903 transfusions. Overall RBC transfusion prevalence rate during postnatal days 1 to 28 was 3.4 transfusion days per 100 admission days, with considerable variation across countries, only partly explained by patient mix. By day 28, 36.5% (95% CI, 31.6%-41.5%) of infants had received at least 1 transfusion. Most transfusions were given based on a defined Hb threshold (748 [82.8%]). Hemoglobin levels before transfusions indicated for threshold were below the restrictive thresholds set by ETTNO in 324 of 729 transfusions (44.4%) and TOP in 265 of 729 (36.4%). Conversely, they were between restrictive and liberal thresholds in 352 (48.3%) and 409 (56.1%) transfusions, respectively, and above liberal thresholds in 53 (7.3%) and 55 (7.5%) transfusions, respectively. Most transfusions given based on threshold had volumes of 15 mL/kg (470 of 738 [63.7%]) and were administered over 3 hours (400 of 738 [54.2%]), but there was substantial variation in dose and duration. Conclusions and Relevance:In this cohort study of very preterm infants, most transfusions indicated for threshold were given for pretransfusion Hb levels above restrictive transfusion thresholds evaluated in recent trials. These results underline the need to optimize practices and for implementation research to support uptake of evidence.

Importance:Red blood cell (RBC) transfusion is a common medical intervention to treat anemia in very preterm neonates; however, best transfusion practices, such as thresholds, remain uncertain. Objective:To develop recommendations for clinicians on the use of RBC transfusions in very preterm neonates. Evidence Review:An international steering committee reviewed evidence from a systematic review of 6 randomized clinical trials (RCTs) that compared high vs low hemoglobin-based or hematocrit-based transfusion thresholds. The steering committee reached consensus on certainty-of-evidence ratings and worked with a panel from stakeholder organizations on reviewing the evidence. With input from parent representatives and the stakeholder panel, the steering committee used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to develop recommendations. Findings:A systematic review of 6 RCTs encompassing 3483 participants (1759 females [51.3%]; mean [SD] age range, 25.9-29.8 [1.5-3.0] weeks) was used as the basis of the recommendations. The ranges for higher hemoglobin concentration (liberal) vs lower hemoglobin concentration (restrictive) threshold study arms were similar across the trials. However, specific thresholds differed based on the severity of illness, which was defined using variable criteria in the trials. There was moderate certainty of evidence that low transfusion thresholds likely had little to no difference in important short-term and long-term outcomes. The recommended hemoglobin thresholds varied on the basis of postnatal week and respiratory support needs. At postnatal weeks 1, 2, and 3 or more, for neonates on respiratory support, the recommended thresholds were 11, 10, and 9 g/dL, respectively; for neonates on no or minimal respiratory support, the recommended thresholds were 10, 8.5, and 7 g/dL, respectively (to convert hemoglobin to grams per liter, multiply by 10.0). Conclusions and Relevance:This consensus statement recommends a restrictive RBC transfusion strategy, with moderate certainty of evidence, for preterm neonates with less than 30 weeks' gestation.

Background Preterm infants commonly receive red blood cell (RBC), platelet and fresh frozen plasma (FFP) transfusions. The aim of this Neonatal Transfusion Network survey was to describe current transfusion practices in Europe and to compare our findings to three recent randomised controlled trials to understand how clinical practice relates to the trial data. Methods From October to December 2020, we performed an online survey among 597 neonatal intensive care units (NICUs) caring for infants with a gestational age (GA) of <32 weeks in 18 European countries. Results Responses from 343 NICUs (response rate: 57%) are presented and showed substantial variation in clinical practice. For RBC transfusions, 70% of NICUs transfused at thresholds above the restrictive thresholds tested in the recent trials and 22% below the restrictive thresholds. For platelet transfusions, 57% of NICUs transfused at platelet count thresholds above 25×10 9 /L in non-bleeding infants of GA of <28 weeks, while the 25×10 9 /L threshold was associated with a lower risk of harm in a recent trial. FFP transfusions were administered for coagulopathy without active bleeding in 39% and for hypotension in 25% of NICUs. Transfusion volume, duration and rate varied by factors up to several folds between NICUs. Conclusions Transfusion thresholds and aspects of administration vary widely across European NICUs. In general, transfusion thresholds used tend to be more liberal compared with data from recent trials supporting the use of more restrictive thresholds. Further research is needed to identify the barriers and enablers to incorporation of recent trial findings into neonatal transfusion practice.

Background: Children affected by fetal and neonatal alloimmune thrombocytopenia (FNAIT) are at risk for severe intracranial haemorrhage and other types of bleeding during pregnancy and after birth. Management in the postnatal period is based on limited evidence. We set out to describe contemporary management and outcomes of patients with FNAIT.Methods: Observational cohort study analysing data on the postnatal treatment and neonatal outcomes of children diagnosed with FNAIT between 2010 and 2020 from seven countries. Cases were recorded in an international dedicated web-based FNAIT Registry.Findings: A total of 389 liveborn neonates with FNAIT were included. Severe thrombocytopenia (platelet count <50 ×10 9 /L) and extreme thrombocytopenia (<10×10 9 /L) was reported in 73% (283/389) and 24% (92/389), respectively. Severe intracranial haemorrhage was detected in 6% (22/389). Thresholds for platelet transfusions in non-bleeding neonates varied from 20 to 50×10 9 /L between centres. Platelet transfusions were administered to 53% (207/389) of neonates, either as random donor platelets (43%, 88/207), human platelet antigen (HPA) matched platelets (41%, 85/207), or both (17%, 35/207). The use of HPA-matched transfusions differed between centres from not being used at all to being first choice and used in 62% of cases. Additional postnatal intravenous immunoglobulins treatment was given in 29% (110/389) of cases, with large variation between centres 12% to 63%.Interpretation: Postnatal management in FNAIT varies greatly between centres internationally, highlighting the lack of consensus on optimal treatments.Funding: Process and Product Development Diagnostic Services, Sanquin (SQI/00034).Declaration of Interest: The authors report no conflict of interest.Ethical Approval: The medical ethical committee of Leiden-Delft-DenHaag provided a waiver-of-consent for the initiating country (G20.074).

Background Children affected by fetal and neonatal alloimmune thrombocytopenia (FNAIT) are at risk of severe intracranial haemorrhage. Management in the postnatal period is based on sparse evidence. We aimed to describe the contemporary management and outcomes of patients with FNAIT in high-income countries. Methods In this multicentre, retrospective, cohort study, we set up a web-based registry for the collection of deidentified data on the management and course of neonates with FNAIT. Eight centres from seven countries (Australia, Norway, Slovenia, Spain, Sweden, the Netherlands, and the USA) participated. Eligibility criteria comprised neonates with FNAIT being liveborn between Jan 1, 2010, and Jan 1, 2020; anti-human platelet antigen (HPA) alloantibodies in maternal serum; confirmed maternal and fetal HPA incompatibility; and bleeding detected at antenatal ultrasound, neonatal thrombocytopenia (<150 x 10(9) platelets per L), or both in the current or previous pregnancy. Clinical data were retrieved from local medical records of the first neonatal admission and entered in the registry. The key outcome was the type of postnatal treatment given to neonates with FNAIT. Other outcomes were daily median platelet counts in the first week of life, median platelet count increment after first unmatched versus first matched transfusions, and the proportion of neonates with mild or severe bleeding. Findings 408 liveborn neonates with FNAIT were entered into the FNAIT registry, of whom 389 from Australia (n=74), Norway (n=56), Slovenia (n=19), Spain (n=55), Sweden (n=31), the Netherlands (n=138), and the USA (n=16) were included in our analyses. The median follow-up was 5 days (IQR 2-9). More neonates were male (241 [64%] of 379) than female (138 [36%]). Severe thrombocytopenia (platelet count <50 x 10(9) platelets per L) was reported in 283 (74%) of 380 neonates, and extreme thrombo-cytopenia (<10 x 10(9) platelets per L) was reported in 92 (24%) neonates. Postnatal platelet count nadir was higher in the no-treatment group than in all other groups. 163 (42%) of 389 neonates with FNAIT received no postnatal treatment. 207 (53%) neonates received platelet transfusions, which were either HPA-unmatched (88 [43%] of 207), HPA-matched (84 [41%]), or a combination of both (35 [17%]). The proportion of neonates who received HPA-matched platelet transfusions varied between countries, ranging from 0% (Slovenia) to 63% (35 of 56 neonates; Norway). Postnatal intravenous immunoglobulin treatment was given to 110 (28%) of 389 neonates (alone [n=19] or in combination with platelet transfusions [n=91]), with the proportion receiving it ranging from 12% (17 of 138 neonates; the Netherlands) to 63% (ten of 16 neonates; the USA) across countries. The median platelet increment was 59 x 10(9) platelets per L (IQR 35-94) after HPA-unmatched platelet transfusions and 98 x 10(9) platelets per L (67-134) after HPA-matched platelet transfusions (p<0 center dot 0001). Severe bleeding was diagnosed in 23 (6%) of 389 liveborn neonates, with one having a severe pulmonary haemorrhage and 22 having severe intracranial haemorrhages. Mild bleeding was diagnosed in 186 (48%) neonates. Interpretation Postnatal management of FNAIT varies greatly between international centres, highlighting the absence of consensus on optimal treatments. Our data suggest that HPA-matched transfusions lead to a larger median platelet count increment than HPA-unmatched transfusions, but whether HPA matching is also associated with a reduced risk of bleeding remains unknown. Copyright (c) 2022 Published by Elsevier Ltd. All rights reserved.

AbstractEltrombopag (ELT) is a thrombopoietic agent approved for immune thrombocytopenia and also a potent iron chelator. Here we found that ELT exhibited dose-dependent opposing effects on in vitro megakaryopoiesis: low concentrations (≤6 µM, ELT6) stimulated megakaryopoiesis, but high concentrations (30 µM, ELT30) suppressed megakaryocyte (MK) differentiation and proliferation. The suppressive effects of ELT30 were reproduced by other iron chelators, supporting iron chelation as a likely mechanism. During MK differentiation, committed MK progenitors (CD34+/CD41+ and CD34−/CD41+ cells) were significantly more sensitive than undifferentiated progenitors (CD34+/CD41− cells) to the suppressive effects of ELT30, which resulted from both decreased proliferation and increased apoptosis. The antiproliferative effects of ELT30 were reversed by increased iron in the culture, as were the proapoptotic effects when exposure to ELT30 was short. Because committed MK progenitors exhibited the highest proliferative rate and the highest sensitivity to iron chelation, we tested whether their iron status influenced their response to ELT during rapid cell expansion. In these studies, iron deficiency reduced the proliferation of CD41+ cells in response to all ELT concentrations. Severe iron deficiency also reduced the number of MKs generated in response to high thrombopoietin concentrations by ∼50%, compared with iron-replete cultures. Our findings support the hypothesis that although iron deficiency can stimulate certain cells and steps in megakaryopoiesis, it can also limit the proliferation of committed MK progenitors, with severity of iron deficiency and degree of thrombopoietic stimulation influencing the ultimate output. Further studies are needed to clarify how megakaryopoiesis, iron deficiency, and ELT stimulation are clinically interrelated.

Over the last decades, as the survival of neonates admitted to the neonatal intensive care unit (NICU) improved, thrombocytopenia became an increasingly important problem in the care of sick term and particularly preterm neonates. In this population, the majority of thrombocytopenias are due to acquired processes, and most resolve with time and/or treatment of the underlying illness. Frequently, however, the etiology of the thrombocytopenia poses a diagnostic dilemma, and – if severe enough – may place the affected neonate at risk of bleeding.

Transfusions should be given for medical indications and based on the clinical context for the individual patient. Clinicians should follow the most current existing clinical guidelines. The neonatal hemostatic system differs significantly from that of children and adults. Still, healthy neonates have a balanced hemostatic system. Since the level of hemoglobin is critical to tissue oxygenation, it is important in the rapidly developing neonate. For preterm neonates, different red blood cell transfusion thresholds should be used based on postnatal age and illness severity. Most hemodynamically stable pediatric intensive care patients with a hemoglobin >70 g/L do not require transfusion. Pediatric massive transfusion protocols should exist in pediatric hospitals. At Karolinska University Hospital, red blood cells, fresh frozen plasma and platelets are transfused in a ratio of 20:20:10 mL/kg to children <50 kg. In liver disease, transfusions can lead to increased bleeding.

This cohort study analyzes the association of closure time in response to adenosine diphosphate (CT-ADP) with bleeding score and the associations of platelet transfusions with change in platelet count, CT-ADP, and bleeding scores in preterm neonates with thrombocytopenia.

This cohort study examines the use of closure time following stimulation with collagen and adenosine diphosphate vs the platelet count as a marker of bleeding in premature neonates with thrombocytopenia.

Vox SanguinisVolume 114, Issue 5 p. 523-530 International Forum Vox Sanguinis International Forum on paediatric indications for blood component transfusion: Summary Mie Topholm Bruun, Mie Topholm Bruun mie.topholm.bruun@rsyd.dk Department of Clinical Immunology, Odense University Hospital, Odense, DenmarkSearch for more papers by this authorMark H. Yazer, Mark H. Yazer myazer@itxm.org The Institute for Transfusion Medicine, Pittsburgh, PA, USASearch for more papers by this authorPhilip C. Spinella, Philip C. Spinella pspinella@wustl.edu Department of Pediatrics, Division of Critical Care Medicine, Washington University in St Louis, St Louis, MO, USASearch for more papers by this authorKjell Titlestad, Kjell Titlestad kjell.titlestad@rsyd.dk Department of Clinical Immunology, Odense University Hospital, Odense, DenmarkSearch for more papers by this authorMiquel Lozano, Miquel Lozano mlozano@clinic.cat orcid.org/0000-0003-2593-833X Department of Hemotherapy and Hemostasis, Hospital Clinic, Barcelona, SpainSearch for more papers by this authorMeghan Delaney, Meghan DelaneySearch for more papers by this authorHana Lejdarová, Hana LejdarováSearch for more papers by this authorDana E. Pavlova, Dana E. PavlovaSearch for more papers by this authorPavel Trakhtman, Pavel TrakhtmanSearch for more papers by this authorNikolay Starostin, Nikolay StarostinSearch for more papers by this authorEugene Zhiburt, Eugene ZhiburtSearch for more papers by this authorMarian G. J. van Kraaij, Marian G. J. van KraaijSearch for more papers by this authorElise Huisman, Elise HuismanSearch for more papers by this authorJose M. Kutner, Jose M. KutnerSearch for more papers by this authorAraci M. Sakashita, Araci M. SakashitaSearch for more papers by this authorAna P. H. Yokoyama, Ana P. H. YokoyamaSearch for more papers by this authorJosune Zubicaray, Josune ZubicaraySearch for more papers by this authorJulián Sevilla, Julián SevillaSearch for more papers by this authorHitoshi Okazaki, Hitoshi OkazakiSearch for more papers by this authorMitsuteru Hiwatari, Mitsuteru HiwatariSearch for more papers by this authorYutaka Nagura, Yutaka NaguraSearch for more papers by this authorPaola Maria Manzini, Paola Maria Manzini orcid.org/0000-0002-0385-9123 Search for more papers by this authorGiuseppina Facco, Giuseppina FaccoSearch for more papers by this authorCostantino Avdis, Costantino AvdisSearch for more papers by this authorLakhvinder Singh, Lakhvinder SinghSearch for more papers by this authorRekha Hans, Rekha HansSearch for more papers by this authorRatti Ram Sharma, Ratti Ram Sharma orcid.org/0000-0002-7415-4665 Search for more papers by this authorPraveen Kumar, Praveen KumarSearch for more papers by this authorAgneta Wikman, Agneta Wikman orcid.org/0000-0002-8810-7974 Search for more papers by this authorEmöke Deschmann, Emöke DeschmannSearch for more papers by this authorHartirathpal Kaur, Hartirathpal KaurSearch for more papers by this authorJoyce Lam Ching Mei, Joyce Lam Ching MeiSearch for more papers by this authorSelina Ho Kah Ying, Selina Ho Kah YingSearch for more papers by this authorKoh Pei Lin, Koh Pei LinSearch for more papers by this authorHelen V. New, Helen V. NewSearch for more papers by this authorRachel Moss, Rachel MossSearch for more papers by this authorAnne Kinmonth, Anne KinmonthSearch for more papers by this authorMary Comande, Mary ComandeSearch for more papers by this authorHelen Savoia, Helen SavoiaSearch for more papers by this authorGemma Crighton, Gemma CrightonSearch for more papers by this authorJoanne Yacobovich, Joanne YacobovichSearch for more papers by this authorVered Yahalom, Vered YahalomSearch for more papers by this authorWendy Lau, Wendy LauSearch for more papers by this author Mie Topholm Bruun, Mie Topholm Bruun mie.topholm.bruun@rsyd.dk Department of Clinical Immunology, Odense University Hospital, Odense, DenmarkSearch for more papers by this authorMark H. Yazer, Mark H. Yazer myazer@itxm.org The Institute for Transfusion Medicine, Pittsburgh, PA, USASearch for more papers by this authorPhilip C. Spinella, Philip C. Spinella pspinella@wustl.edu Department of Pediatrics, Division of Critical Care Medicine, Washington University in St Louis, St Louis, MO, USASearch for more papers by this authorKjell Titlestad, Kjell Titlestad kjell.titlestad@rsyd.dk Department of Clinical Immunology, Odense University Hospital, Odense, DenmarkSearch for more papers by this authorMiquel Lozano, Miquel Lozano mlozano@clinic.cat orcid.org/0000-0003-2593-833X Department of Hemotherapy and Hemostasis, Hospital Clinic, Barcelona, SpainSearch for more papers by this authorMeghan Delaney, Meghan DelaneySearch for more papers by this authorHana Lejdarová, Hana LejdarováSearch for more papers by this authorDana E. Pavlova, Dana E. PavlovaSearch for more papers by this authorPavel Trakhtman, Pavel TrakhtmanSearch for more papers by this authorNikolay Starostin, Nikolay StarostinSearch for more papers by this authorEugene Zhiburt, Eugene ZhiburtSearch for more papers by this authorMarian G. J. van Kraaij, Marian G. J. van KraaijSearch for more papers by this authorElise Huisman, Elise HuismanSearch for more papers by this authorJose M. Kutner, Jose M. KutnerSearch for more papers by this authorAraci M. Sakashita, Araci M. SakashitaSearch for more papers by this authorAna P. H. Yokoyama, Ana P. H. YokoyamaSearch for more papers by this authorJosune Zubicaray, Josune ZubicaraySearch for more papers by this authorJulián Sevilla, Julián SevillaSearch for more papers by this authorHitoshi Okazaki, Hitoshi OkazakiSearch for more papers by this authorMitsuteru Hiwatari, Mitsuteru HiwatariSearch for more papers by this authorYutaka Nagura, Yutaka NaguraSearch for more papers by this authorPaola Maria Manzini, Paola Maria Manzini orcid.org/0000-0002-0385-9123 Search for more papers by this authorGiuseppina Facco, Giuseppina FaccoSearch for more papers by this authorCostantino Avdis, Costantino AvdisSearch for more papers by this authorLakhvinder Singh, Lakhvinder SinghSearch for more papers by this authorRekha Hans, Rekha HansSearch for more papers by this authorRatti Ram Sharma, Ratti Ram Sharma orcid.org/0000-0002-7415-4665 Search for more papers by this authorPraveen Kumar, Praveen KumarSearch for more papers by this authorAgneta Wikman, Agneta Wikman orcid.org/0000-0002-8810-7974 Search for more papers by this authorEmöke Deschmann, Emöke DeschmannSearch for more papers by this authorHartirathpal Kaur, Hartirathpal KaurSearch for more papers by this authorJoyce Lam Ching Mei, Joyce Lam Ching MeiSearch for more papers by this authorSelina Ho Kah Ying, Selina Ho Kah YingSearch for more papers by this authorKoh Pei Lin, Koh Pei LinSearch for more papers by this authorHelen V. New, Helen V. NewSearch for more papers by this authorRachel Moss, Rachel MossSearch for more papers by this authorAnne Kinmonth, Anne KinmonthSearch for more papers by this authorMary Comande, Mary ComandeSearch for more papers by this authorHelen Savoia, Helen SavoiaSearch for more papers by this authorGemma Crighton, Gemma CrightonSearch for more papers by this authorJoanne Yacobovich, Joanne YacobovichSearch for more papers by this authorVered Yahalom, Vered YahalomSearch for more papers by this authorWendy Lau, Wendy LauSearch for more papers by this author First published: 13 May 2019 https://doi.org/10.1111/vox.12763Citations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. 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Eltrombopag (ELT), a small molecular thrombopoietin (TPO) mimetic approved for children and adults, could offer a therapeutic alternative to selected neonates and young children with chronic thrombocytopenias. ELT has also been proposed as a potential anti-cancer drug due to its anti-proliferative effects in tumor cells, which are mediated by its strong iron chelating properties. This raises the potential concern that rapidly proliferating normal cells, like bone marrow cells in neonates or young infants, could also be susceptible to the anti-proliferative effects of ELT. In this study, we first assessed the responses of neonatal (cord blood, CB) and adult (peripheral blood, PB) megakaryocyte (MK) progenitors to increasing concentrations of ELT, TPO and Romiplostim (ROM) in vitro. Consistent with the previously described pattern of neonatal megakaryopoiesis, CB progenitors generated 10-times more MKs, which were of lower ploidy but had higher CD42 surface expression levels than PB-MKs. Unlike TPO or ROM, ELT exhibited dose-dependent opposing effects on in vitro megakaryopoiesis: Low concentrations (≤6µM) stimulated megakaryopoiesis, but high concentrations (30µM) suppressed MK differentiation and proliferation, as evidenced by a severe reduction in the percentage and absolute number of CD41+ cells after 7 days of culture. The toxic effects of high ELT concentrations were not abrogated by the addition of TPO at concentrations achieved in hyporegenerative thrombocytopenias (3 ng/mL), and were reproduced by the addition of the iron chelators deferoxamine (DFO) or deferiprone (DFP) at concentrations of 100µM to MK cultures, suggesting iron deficiency as a potential mechanism. To further assess the iron chelating effects of ELT in human MKs, we used the calcein assay. In K562 cells, as well as in CB MKs, ELT concentrations >10µM reduced the labile intracellular iron pool (LIP) to lower levels than the iron chelator DFP at a concentration of 200 µM, indicating the strength of ELT's iron chelating properties. These concentrations of ELT also resulted in a severe reduction of mitochondrial transmembrane potential, detected by the JC-1 assay, decreased proliferation (EdU click assay) and apoptosis (Annexin-V binding). During MK differentiation, committed MK progenitors (CD34+/CD41+ cells) were the cell population most sensitive to the antiproliferative and apoptotic effects of high-dose ELT. Next, we evaluated whether the iron status of differentiated MK progenitors would influence their responses to ELT. To test this, we generated iron-depleted and iron-repleted CB-MK progenitors by culturing CD34+ cells for 7 days in the presence of apo-transferrin (iron-free) or holo-transferrin (iron-saturated), followed by a 72 hour culture with different concentrations of ELT. These studies revealed a strong iron status/ELT dose interaction (interaction p<0.0001); In iron-depleted cultures, 30 µM ELT and 100 µM DFO similarly impaired MK expansion and induced MK apoptosis, but these effects were attenuated in iron-repleted cultures. Interestingly, iron-depleted adult PB progenitors did not show reduced MK expansion or increased apoptosis in response to 30 µM ELT, suggesting a lower susceptibility of adult megakaryopoiesis to the iron chelating effects of ELT. Taken together, these findings suggest that iron status is an important variable affecting the response to ELT, particularly in neonates and children. Disclosures Cooper: Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Principia: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Porter:Celgene: Consultancy, Honoraria; Protagonism: Honoraria; Agios: Consultancy, Honoraria; La Jolla: Honoraria; Vifor: Honoraria; Silence therapeutics: Honoraria; Bluebird bio: Consultancy, Honoraria. Bussel:Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; argenx: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; RallyBio: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Kezar Life Sciences: Consultancy, Membership on an entity's Board of Directors or advisory committees; Physician Education Resource: Speakers Bureau; 3S Bio: Speakers Bureau; Rigel: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Tranquil: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Momenta Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Dova Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; UCB: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Sola-Visner:Sysmex America, Inc.: Other: Laboratory equipment on loan, Research Funding.

AimTo assess the prevalence, types and indications for fluid bolus therapy in neonates with haemodynamic compromise.MethodsThis was a pragmatic, international, multicentre observational study in neonatal units across Australasia, Europe and North America with a predefined study period of 10–15 study days per participating neonatal unit between December 2015 and March 2017. Infants ≤28 days of age who received a fluid bolus for the management of haemodynamic compromise (≥10 mL/kg given at ≤6 h) were included.ResultsA total of 163 neonates received a bolus over 8479 eligible patient days in 41 neonatal units. Prevalence of fluid bolus therapy varied between centres from 0 to 28.6% of admitted neonates per day, with a pooled prevalence rate of 1.5% (95% confidence interval 1.1–1.9%). The most common fluid used was 0.9% sodium chloride (129/163; 79%), and the volume of fluid administered was most commonly 10 mL/kg (115/163; 71%) over a median of 30 min (interquartile range 20–60). The most frequent indications were hypotension (n = 56; 34%), poor perfusion (n = 20; 12%) and metabolic acidosis (n = 20; 12%). Minimal or no clinical improvement was reported by clinicians in 66 of 163 cases (40%).ConclusionsWide international variations in types, indications and effects of fluid bolus administration in haemodynamically compromised neonates suggest uncertainty in the risk–benefit profile. This is likely to reflect the lack of robust evidence to support the efficacy of different fluid types, doses and appropriate indications. Together, these highlight a need for further clinically relevant studies.

Commentary on: Tarnow-Mordi W, Stenson B, Kirby A, Juszczak E, Donoghoe M, Deshpande S, et al. Outcomes of Two Trials of Oxygen-Saturation Targets in Preterm Infants. N Engl J Med 2016; 374: 749–60. Oxygen-saturation target range in extremely preterm infants is an important question of the daily practice in the NICUs, because significant complications such as ROP and BPD can be associated with oxygen exposure outside physiological boundaries. Observational data suggested that saturation <90% was associated with lower rate of ROP without increased rate of CP or death 1. These data led to practice change: targeting lower oxygen saturations in the NICUs without strong evidence of its safety and efficacy from large RCTs. To answer the question whether a lower saturation target range (85–89%) is superior to a higher saturation target range (91–95%) on an outcome of death or major disability at 18–24 months corrected age, five comparative effectiveness trials of oxygen saturation targeting in infants <28 weeks' gestation (the Neonatal Oxygen Prospective Meta-analysis (NeOProM) Collaboration) were designed. The trials were planned similarly and enrolled ~5000 preterm infants <28 weeks of gestation. The report presented the outcomes of two of these trials, the Australian and U.K. BOOST-II trials in children up to a corrected age of two years. As previously reported 2, the NeOProM trials encountered several problems: (i) an oxygen-saturation calibration problem was found in the pulse oximeters used in two of the NeOProM trials (COT, UK BOOST-II): approximately a third fewer oxygen-saturation values between 87 and 90% were displayed than expected, and values >87% were shifted up by 1–2% points; (ii) additionally, when the SUPPORT trial found that targeting the lower oxygen-saturation range resulted in significantly lower rate of ROP, but higher mortality at discharge compared with the higher oxygen-saturation range 3, the BOOST-II trial was stopped early, because the safety monitoring committees found that the pooled safety analysis of the two trials showed similar results to SUPPORT at 36 weeks' postmenstrual age; (iii) none of the NeOProM trials managed to keep the infants' oxygen saturation in the target range: all median oxygen saturations were higher (>89%) than the predetermined in the lower saturation target group, and there was also significant overlap in oxygen saturations achieved. This meta-analysis of the two BOOST-II trials 4 confirms the findings of the SUPPORT that targeting lower oxygen saturation does not increase major disability, however, increases the rate of death. The authors conclude that at present, the most rigorously evaluated evidence for policy is that targeting an oxygen saturation of 91–95% is safer than targeting an oxygen saturation of 85–89%. However, controversy still remains around dynamic saturation target ranges and alarm settings 2 over the neonatal period. Tissue oxygenation, which depends on multiple factors, including oxygen saturation, is affected by foetal haemoglobin concentration and blood haemoglobin level, along with several other factors. Although the quality of the existing evidence has been graded as moderate to low 5, we think that until more sophisticated methods and individual patient data are available, targeting oxygen saturation between 91 and 95% is a reasonable initial approach for extremely preterm infants. Still, in units with low rates of mortality and but high rates of severe ROP, lower saturation targets have been suggested 2. https://ebneo.org/2017/01/oxygen-saturation-targets-in-extremely-preterm-infants None. None.

Bone marrow megakaryocytes produce platelets by extending long cytoplasmic protrusions, designated proplatelets, into sinusoidal blood vessels. Although microtubules are known to regulate platelet production, the underlying mechanism of proplatelet elongation has yet to be resolved. Here we report that proplatelet formation is a process that can be divided into repetitive phases (extension, pause, and retraction), as revealed by differential interference contrast and fluorescence loss after photoconversion time-lapse microscopy. Furthermore, we show that microtubule sliding drives proplatelet elongation and is dependent on cytoplasmic dynein under static and physiological shear stress by using fluorescence recovery after photobleaching in proplatelets with fluorescence-tagged β1-tubulin. A refined understanding of the specific mechanisms regulating platelet production will yield strategies to treat patients with thrombocythemia or thrombocytopenia.

There is significant world-wide variability in platelet transfusion thresholds used to transfuse thrombocytopenic neonates. A large multicenter randomized controlled trial comparing 2 different platelet transfusion thresholds in neonates is currently ongoing, and should provide data to guide transfusion practice. However, several studies have found that factors other than the degree of thrombocytopenia determine the bleeding risk. Thus, it will be important to develop better tests to assess primary hemostasis and bleeding risk in neonates.