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Sokou R, Parastatidou S, Konstantinidi A, Tsantes AG, Iacovidou N, Piovani D, Bonovas S, Tsantes AE. Contemporary tools for evaluation of hemostasis in neonates. Where are we and where are we headed? Blood Rev 2024; 64:101157. [PMID: 38016836 DOI: 10.1016/j.blre.2023.101157] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 11/30/2023]
Abstract
The assessment of hemostatic disorders in neonates is crucial, but remains challenging for clinicians. Although the concept of developmental hemostasis is widely accepted among hemostasis specialists globally, it is probably under-recognized by clinicians and laboratory practitioners. In parallel with age-dependent hemostatic status maturation, comprehension of the differences between normal values is crucial for the accurate diagnosis of potential hemorrhagic and thrombotic disorders of the vulnerable neonatal population. This review outlines the basics of developmental hemostasis and the features of the available coagulation testing methods, with a focus on novel tools for evaluating the neonatal hemostatic profile. Common errors, issues, and pitfalls during the assessment of neonatal hemostasis are discussed, along with their impact on patient management. Current knowledge gaps and research areas are addressed. Further studying to improve our understanding of developmental hemostasis and its reflection on everyday clinical practice is warranted.
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Affiliation(s)
- Rozeta Sokou
- Neonatal Intensive Care Unit, "Agios Panteleimon" General Hospital of Nikea, Piraeus, Greece.
| | | | | | - Andreas G Tsantes
- Laboratory of Haematology and Blood Bank Unit, "Attiko" Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece
| | - Nicoletta Iacovidou
- Neonatal Department, National and Kapodistrian University of Athens, Aretaieio Hospital, Athens, Greece
| | - Daniele Piovani
- Department of Biomedical Sciences, Humanitas University, Milan, Italy; IRCCS Humanitas Research Hospital, Milan, Italy
| | - Stefanos Bonovas
- Department of Biomedical Sciences, Humanitas University, Milan, Italy; IRCCS Humanitas Research Hospital, Milan, Italy
| | - Argirios E Tsantes
- Laboratory of Haematology and Blood Bank Unit, "Attiko" Hospital, School of Medicine, National and Kapodistrian University of Athens, Greece
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Pablo-Moreno JAD, Serrano LJ, Revuelta L, Sánchez MJ, Liras A. The Vascular Endothelium and Coagulation: Homeostasis, Disease, and Treatment, with a Focus on the Von Willebrand Factor and Factors VIII and V. Int J Mol Sci 2022; 23:ijms23158283. [PMID: 35955419 PMCID: PMC9425441 DOI: 10.3390/ijms23158283] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/22/2022] [Accepted: 07/23/2022] [Indexed: 11/27/2022] Open
Abstract
The vascular endothelium has several important functions, including hemostasis. The homeostasis of hemostasis is based on a fine balance between procoagulant and anticoagulant proteins and between fibrinolytic and antifibrinolytic ones. Coagulopathies are characterized by a mutation-induced alteration of the function of certain coagulation factors or by a disturbed balance between the mechanisms responsible for regulating coagulation. Homeostatic therapies consist in replacement and nonreplacement treatments or in the administration of antifibrinolytic agents. Rebalancing products reestablish hemostasis by inhibiting natural anticoagulant pathways. These agents include monoclonal antibodies, such as concizumab and marstacimab, which target the tissue factor pathway inhibitor; interfering RNA therapies, such as fitusiran, which targets antithrombin III; and protease inhibitors, such as serpinPC, which targets active protein C. In cases of thrombophilia (deficiency of protein C, protein S, or factor V Leiden), treatment may consist in direct oral anticoagulants, replacement therapy (plasma or recombinant ADAMTS13) in cases of a congenital deficiency of ADAMTS13, or immunomodulators (prednisone) if the thrombophilia is autoimmune. Monoclonal-antibody-based anti-vWF immunotherapy (caplacizumab) is used in the context of severe thrombophilia, regardless of the cause of the disorder. In cases of disseminated intravascular coagulation, the treatment of choice consists in administration of antifibrinolytics, all-trans-retinoic acid, and recombinant soluble human thrombomodulin.
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Affiliation(s)
- Juan A. De Pablo-Moreno
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University, 28040 Madrid, Spain; (J.A.D.P.-M.); (L.J.S.)
| | - Luis Javier Serrano
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University, 28040 Madrid, Spain; (J.A.D.P.-M.); (L.J.S.)
| | - Luis Revuelta
- Department of Physiology, School of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain;
| | - María José Sánchez
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas (CSIC), Junta de Andalucía, Pablo de Olavide University, 41013 Sevilla, Spain;
| | - Antonio Liras
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University, 28040 Madrid, Spain; (J.A.D.P.-M.); (L.J.S.)
- Correspondence:
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The role of the calibrated automated thrombogram in neonates: describing mechanisms of neonatal haemostasis and evaluating haemostatic drugs. Eur J Pediatr 2022; 181:23-33. [PMID: 34283272 PMCID: PMC8760221 DOI: 10.1007/s00431-021-04196-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/11/2021] [Accepted: 07/01/2021] [Indexed: 12/04/2022]
Abstract
Premature infants are at high risk of haemorrhage and thrombosis. Our understanding of the differences between the neonatal and adult haemostatic system is evolving. There are several limitations to the standard coagulation tests used in clinical practice, and there is currently a lack of evidence to support many of the transfusion practices in neonatal medicine. The evaluation of haemostasis is particularly challenging in neonates due to their limited blood volume. The calibrated automated thrombogram (CAT) is a global coagulation assay, first described in 2002, which evaluates both pro- and anti-coagulant pathways in platelet-rich or platelet-poor plasma. In this review, the current applications and limitations of CAT in the neonatal population are discussed.Conclusion: CAT has successfully elucidated several differences between haemostatic mechanisms in premature and term neonates compared with adults. Moreover, it has been used to evaluate the effect of a number of haemostatic drugs in a pre-clinical model. However, the lack of evidence of CAT as an accurate predictor of neonatal bleeding, blood volume required and the absence of an evidence-based treatment algorithm for abnormal CAT results limit its current application as a bedside clinical tool for the evaluation of sick neonates. What is Known: • The Calibrated automated thrombogram (CAT) is a global coagulation assay which evaluates pro- and anti-coagulant pathways. • CAT provides greater information than standard clotting tests and has been used in adults to evaluate bleeding risk. What is New: • This review summarises the physiological differences in haemostasis between neonates and adults described using CAT. • The haemostatic effect of several drugs has been evaluated in neonatal plasma using CAT.
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Rey Y Formoso V, Barreto Mota R, Soares H. Developmental hemostasis in the neonatal period. World J Pediatr 2022; 18:7-15. [PMID: 34981411 DOI: 10.1007/s12519-021-00492-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/17/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND The hemostatic system is complex and evolves continuously since gestation and well into the adult years, in a process known as "developmental hemostasis." DATA SOURCES A comprehensive review was performed after an extensive literature search on PubMed/MEDLINE concerning developmental hemostasis during the neonatal period. Relevant cross references were also included. RESULTS Although part of a system, each component of the hemostatic system evolves differently, with many displaying both quantitative and qualitative age-related differences. This leads to drastic disparities between the coagulation system of neonates and both other children's and adults', while still maintaining a generally balanced and physiological hemostasis. The motives behind this process remain to be fully elucidated but may be, at least in part, related to non-hemostatic factors. CONCLUSIONS Knowledge regarding "developmental hemostasis" is essential for everyone caring for newborns or even children in general and in this review, we describe each hemostatic system component's neonatal characteristics and age-related progression as well as explore some of the possible physiological motives behind the process.
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Affiliation(s)
- Vicente Rey Y Formoso
- Neonatology Department (Reference Center for Congenital Heart Diseases), São João University Hospital Center, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.
| | - Ricardo Barreto Mota
- Neonatology Department (Reference Center for Congenital Heart Diseases), São João University Hospital Center, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal
| | - Henrique Soares
- Neonatology Department (Reference Center for Congenital Heart Diseases), São João University Hospital Center, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.,Faculty of Medicine, Porto University, Porto, Portugal
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Sheriff J, Malone LE, Avila C, Zigomalas A, Bluestein D, Bahou WF. Shear-Induced Platelet Activation is Sensitive to Age and Calcium Availability: A Comparison of Adult and Cord Blood. Cell Mol Bioeng 2020; 13:575-590. [PMID: 33281988 PMCID: PMC7704822 DOI: 10.1007/s12195-020-00628-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 06/16/2020] [Indexed: 10/24/2022] Open
Abstract
INTRODUCTION Antiplatelet therapy for neonates and infants is often extrapolated from the adult experience, based on limited observation of agonist-induced neonatal platelet hypoactivity and poor understanding of flow shear-mediated platelet activation. Therefore, thrombotic events due to device-associated disturbed flow are inadequately mitigated in critically ill neonates with indwelling umbilical catheters and infants receiving cardiovascular implants. METHODS Whole blood (WB), platelet-rich plasma (PRP), and gel-filtered platelets (GFP) were prepared from umbilical cord and adult blood, and exposed to biochemical agonists or pathological shear stress of 70 dyne/cm2. We evaluated α-granule release, phosphatidylserine (PS) scrambling, and procoagulant response using P-selectin expression, Annexin V binding, and thrombin generation (PAS), respectively. Activation modulation due to depletion of intracellular and extracellular calcium, requisite second messengers, was also examined. RESULTS Similar P-selectin expression was observed for sheared adult and cord platelets, with concordant inhibition due to intracellular and extracellular calcium depletion. Sheared cord platelet Annexin V binding and PAS activity was similar to adult values in GFP, but lower in PRP and WB. Annexin V on sheared cord platelets was calcium-independent, with PAS slightly reduced by intracellular calcium depletion. CONCLUSIONS Increased PS activity on purified sheared cord platelets suggest that their intrinsic function under pathological flow conditions is suppressed by cell-cell or plasmatic components. Although secretory functions of adult and cord platelets retain comparable calcium-dependence, PS exposure in sheared cord platelets is uniquely calcium-independent and distinct from adults. Identification of calcium-regulated developmental disparities in shear-mediated platelet function may provide novel targets for age-specific antiplatelet therapy.
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Affiliation(s)
- Jawaad Sheriff
- Department of Biomedical Engineering, T08-50 Health Sciences Center, Stony Brook University, Stony Brook, NY 11794-8084 USA
| | - Lisa E. Malone
- Division of Hematology and Oncology, Department of Medicine, Stony Brook University, Stony Brook, NY 11794 USA
| | - Cecilia Avila
- Department of Obstetrics, Gynecology and Reproductive Medicine, Stony Brook University, Stony Brook, NY 11794 USA
| | - Amanda Zigomalas
- Department of Biomedical Engineering, T08-50 Health Sciences Center, Stony Brook University, Stony Brook, NY 11794-8084 USA
| | - Danny Bluestein
- Department of Biomedical Engineering, T08-50 Health Sciences Center, Stony Brook University, Stony Brook, NY 11794-8084 USA
| | - Wadie F. Bahou
- Division of Hematology and Oncology, Department of Medicine, Stony Brook University, Stony Brook, NY 11794 USA
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Schlagenhauf A, Zieger B, Muntean W. Contact activation and acquired von Willebrand syndrome during neonatal extracorporeal circulation. J Thromb Haemost 2020; 18:3119-3121. [PMID: 33463037 DOI: 10.1111/jth.15058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 06/25/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Axel Schlagenhauf
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Barbara Zieger
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Wolfgang Muntean
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University Graz, Graz, Austria
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Abstract
Although the hemostatic potential of adult platelets has been investigated extensively, regulation of platelet function during fetal life is less clear. Recent studies have provided increasing evidence for a developmental control of platelet function during fetal ontogeny. Fetal platelets feature distinct differences in reactive properties compared with adults. These differences very likely reflect a modified hemostatic and homeostatic environment in which platelet hyporeactivity contributes to prevent pathological clot formation on the one hand but still ensures sufficient hemostasis on the other hand. In this review, recent findings on the ontogeny of platelet function and reactivity are summarized, and implications for clinical practice are critically discussed. This includes current platelet-transfusion practice and its potential risk in premature infants and neonates.
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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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Haidl H, Pohl S, Leschnik B, Gallistl S, Muntean W, Schlagenhauf A. Neonatal thrombocytopenia: Thrombin generation in presence of reduced platelet counts and effects of rFVIIa in cord blood. Sci Rep 2019; 9:8014. [PMID: 31142810 PMCID: PMC6541708 DOI: 10.1038/s41598-019-44199-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 05/07/2019] [Indexed: 11/12/2022] Open
Abstract
Healthy neonates exhibit a well-functioning haemostatic system despite peculiarities regarding composition of clotting factors and inhibitors as well as impaired platelet aggregation. Thrombocytopenia and severe bleeding events are feared in sick infants. Recombinant factor VIIa (rFVIIa) is a haemostatic agent used as a last resort in neonates with refractory bleedings. Aim of this study was to investigate in-vitro (i) changes in thrombin generation with different platelet counts, (ii) effects of rFVIIa under conditions of thrombocytopenia and (iii) potentially differing dose-response of rFVIIa in cord blood as a surrogate for neonatal blood compared to adult blood. Thrombin generation parameters were observed in cord blood plasma and adult plasma with various platelet counts, with or without addition of rFVIIa, respectively. Low platelet counts did not influence thrombin generation in cord blood in contrast to adult blood. RFVIIa primarily affected lag time throughout all platelet concentrations. Interestingly, peak height was reduced exclusively in cord blood plasma after addition of rFVIIa. No significant differences regarding dose-response were observed between cord blood and adult blood. In contrast to adult blood, thrombocytopenia in cord blood does not significantly influence thrombin generation. Even at very low platelet counts there is enough negatively charged surface to support rFVIIa action in plasma from cord blood and adult blood in-vitro.
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Affiliation(s)
- Harald Haidl
- Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| | - Sina Pohl
- Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| | - Bettina Leschnik
- Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| | - Siegfried Gallistl
- Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| | - Wolfgang Muntean
- Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| | - Axel Schlagenhauf
- Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria.
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Ngo AT, Sheriff J, Rocheleau AD, Bucher M, Jones KR, Sepp ALI, Malone LE, Zigomalas A, Maloyan A, Bahou WF, Bluestein D, McCarty OJT, Haley KM. Assessment of neonatal, cord, and adult platelet granule trafficking and secretion. Platelets 2019; 31:68-78. [PMID: 30810440 PMCID: PMC6711836 DOI: 10.1080/09537104.2019.1573314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 02/01/2019] [Accepted: 01/16/2019] [Indexed: 10/27/2022]
Abstract
Despite the transient hyporeactivity of neonatal platelets, full-term neonates do not display a bleeding tendency, suggesting potential compensatory mechanisms which allow for balanced and efficient neonatal hemostasis. This study aimed to utilize small-volume, whole blood platelet functional assays to assess the neonatal platelet response downstream of the hemostatic platelet agonists thrombin and adenosine diphosphate (ADP). Thrombin activates platelets via the protease-activated receptors (PARs) 1 and 4, whereas ADP signals via the receptors P2Y1 and P2Y12 as a positive feedback mediator of platelet activation. We observed that neonatal and cord blood-derived platelets exhibited diminished PAR1-mediated granule secretion and integrin activation relative to adult platelets, correlating to reduced PAR1 expression by neonatal platelets. PAR4-mediated granule secretion was blunted in neonatal platelets, correlating to lower PAR4 expression as compared to adult platelets, while PAR4 mediated GPIIb/IIIa activation was similar between neonatal and adult platelets. Under high shear stress, cord blood-derived platelets yielded similar thrombin generation rates but reduced phosphatidylserine expression as compared to adult platelets. Interestingly, we observed enhanced P2Y1/P2Y12-mediated dense granule trafficking in neonatal platelets relative to adults, although P2Y1/P2Y12 expression in neonatal, cord, and adult platelets were similar, suggesting that neonatal platelets may employ an ADP-mediated positive feedback loop as a potential compensatory mechanism for neonatal platelet hyporeactivity.
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Affiliation(s)
- Anh T.P. Ngo
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Jawaad Sheriff
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Anne D. Rocheleau
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Matthew Bucher
- Knight Cardiovascular Institute, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
- Department of Obstetrics and Gynecology, Oregon Health
& Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Kendra R. Jones
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Anna-Liisa I. Sepp
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Lisa E. Malone
- Division of Hematology, Department of Medicine, Stony Brook
University, Stony Brook, NY, USA 11794
| | - Amanda Zigomalas
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Alina Maloyan
- Knight Cardiovascular Institute, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
- Department of Obstetrics and Gynecology, Oregon Health
& Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Wadie F. Bahou
- Division of Hematology, Department of Medicine, Stony Brook
University, Stony Brook, NY, USA 11794
| | - Danny Bluestein
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Owen J. T. McCarty
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Kristina M. Haley
- The Hemophilia Center, Oregon Health & Science
University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
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Schlagenhauf A, Haidl H, Pohl S, Weiss EC, Leschnik B, Gallistl S, Muntean W. Polyphosphate in Neonates: Less Shedding from Platelets and Divergent Prothrombotic Capacity Due to Lower TFPI Levels. Front Physiol 2017; 8:586. [PMID: 28970801 PMCID: PMC5609555 DOI: 10.3389/fphys.2017.00586] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/31/2017] [Indexed: 12/28/2022] Open
Abstract
Background: The neonatal hemostatic system exhibits a fragile balance featuring lower levels of clotting factors as well as inhibitors. Neonatal platelets show in-vitro hypoaggregability, but neonates exhibit well-functioning primary and secondary hemostasis despite this impairment. Recently, polyphosphate shed by activated platelets has been shown to induce a prothrombotic shift on the plasmatic coagulation system of adults. The impact of platelet derived polyphosphate might differ in neonates due to aforementioned peculiarities. Aims: We aimed to comparatively determine polyphosphate content and release from adult and neonatal platelets and to determine its impact on thrombin generation in plasma from adult and cord blood. Methods: Polyphosphate was extracted from adult and neonatal platelet lysates and releasates using silica spin-columns and quantified with a DAPI based fluorescence assay. The impact of exogenous polyphosphate in various concentrations (208–0.026 μg/ml) on thrombin generation was evaluated in plasma from adult and cord blood as well as in adult plasma with reduced tissue factor pathway inhibitor (TFPI) levels using calibrated automated thrombography. Results: Polyphosphate content was comparable in both groups, but the fraction of released polyphosphate upon stimulation with thrombin receptor activating peptide was lower in neonatal samples (adult: 84.1 ± 12.9%; cord: 58.8 ± 11.2%). Relative impact of polyphosphate on lag time of thrombin generation was higher in adult samples compared to samples from cord blood (adult: 41.0% [IQR: 35.2–71.8%] of vehicle; cord: 73.4% [IQR: 70.2–91.4%] of vehicle). However, in samples from cord blood, lower concentrations of polyphosphate were required to obtain maximal impact on thrombin generation (adult: 26 μg/ml; cord: 0.814 μg/ml). PolyP affected thrombin generation in adult plasma similarly to cord plasma, when the TFPI concentration was reduced to neonatal levels. Conclusion: Differences in the impact of polyphosphate on adult and neonatal coagulation are largely caused by differences in TFPI levels. Lower polyphosphate release from neonatal platelets, but lower optimum concentration to drive neonatal plasmatic hemostasis emphasizes the well-matched, but fragile interplay between platelets and coagulation in newborns. A potential developmental mismatch should be considered when transfusing adult platelets into neonates.
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Affiliation(s)
- Axel Schlagenhauf
- Department of General Pediatrics and Adolescent Medicine, Medical University of GrazGraz, Austria
| | - Harald Haidl
- Department of General Pediatrics and Adolescent Medicine, Medical University of GrazGraz, Austria
| | - Sina Pohl
- Department of General Pediatrics and Adolescent Medicine, Medical University of GrazGraz, Austria
| | - Eva-Christine Weiss
- Department of Obstetrics and Gynecology, Medical University of GrazGraz, Austria
| | - Bettina Leschnik
- Department of General Pediatrics and Adolescent Medicine, Medical University of GrazGraz, Austria
| | - Siegfried Gallistl
- Department of General Pediatrics and Adolescent Medicine, Medical University of GrazGraz, Austria
| | - Wolfgang Muntean
- Department of General Pediatrics and Adolescent Medicine, Medical University of GrazGraz, Austria
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Haley KM, Recht M, McCarty OJ. Neonatal platelets: mediators of primary hemostasis in the developing hemostatic system. Pediatr Res 2014; 76:230-7. [PMID: 24941213 PMCID: PMC4348010 DOI: 10.1038/pr.2014.87] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 03/19/2014] [Indexed: 12/16/2022]
Abstract
The human hemostatic system is developmentally regulated, resulting in qualitative and quantitative differences in the mediators of primary and secondary hemostasis as well as fibrinolysis in neonates and infants. Although gestational age-related differences in coagulation factor levels occur, the existence of a unique neonatal platelet phenotype remains controversial. Complicated by difficulties in obtaining adequate neonatal blood volumes with which to perform functional assays, ambiguity surrounds the characterization of neonatal platelets. Thus, much of the current knowledge of neonatal platelet function has been based on studies from cord blood samples. Studies suggest that cord blood-derived platelets, as a surrogate for neonatal platelets, are hypofunctional when compared with adult platelets. This relative platelet dysfunction, combined with a propensity toward thrombocytopenia in the neonatal intensive care unit population, creates a clinical conundrum regarding the appropriate administration of platelet transfusions. This review provides an appraisal of the distinct functional phenotype of neonatal platelets. Neonatal platelet transfusion practices and the impact of the relatively hypofunctional neonatal platelet on those practices will be considered.
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Affiliation(s)
- Kristina M. Haley
- The Hemophilia Center, Oregon Health & Science University, Portland, OR, USA
| | - Michael Recht
- The Hemophilia Center, Oregon Health & Science University, Portland, OR, USA
| | - Owen J.T. McCarty
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, USA
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13
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Schlagenhauf A, Haidl H, Leschnik B, Leis HJ, Heinemann A, Muntean W. Prostaglandin E2 levels and platelet function are different in cord blood compared to adults. Thromb Haemost 2014; 113:97-106. [PMID: 25118631 DOI: 10.1160/th14-03-0218] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 07/01/2014] [Indexed: 11/05/2022]
Abstract
Neonatal platelets support primary haemostasis and thrombin generation as well as adult platelets, despite observable hypoaggregability in vitro. High prostaglandin E2 levels at accouchement could account for inhibited platelet function via the EP4 receptor. We set out to determine prostaglandin E2 plasma levels in cord blood of healthy neonates and evaluate the impact of prostaglandin E2 on platelet function in adult and cord blood samples. Prostaglandin E2 plasma levels were measured in cord blood and venous adult blood using GC-MS. Impact of prostaglandin E2 on platelet aggregation was measured by spiking cord blood and adult samples. Contributions of EP3 and EP4 receptors were evaluated using respective antagonists. Intracellular cAMP concentrations were measured using a commercial ELISA-kit. Prostaglandin E2 plasma levels were substantially higher in cord blood than in adult samples. Spiking with prostaglandin E2 resulted in a slight but consistent reduction of platelet aggregation in adult blood, but response to PGE2 was blunted in cord blood samples. Aggregation response of spiked adult samples was still higher than with non-spiked cord blood samples. Blockage of EP4 receptors resulted in improved platelet aggregation in adult platelets upon prostaglandin E2 spiking, while aggregation in cord blood samples remained unaltered. Intracellular cAMP concentrations after preincubation with prostaglandin E2 were only increased in adult samples. In conclusion, very high prostaglandin E2 concentrations in cord blood affect platelet function. This effect may partially explain neonatal platelet hypoaggregability. Peak levels of prostaglandin E2 can potentially protect against birth stress-induced platelet activation.
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Affiliation(s)
- Axel Schlagenhauf
- Axel Schlagenhauf, PhD, Department of General Pediatrics and Adolescent Medicine, Medical University of Graz, Auenbruggerplatz 34/II, A-8036 Graz, Austria, Tel.: +43 316 385 14031, Fax: +43 316 385 13264, E-mail:
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Microparticles in newborn cord blood: Slight elevation after normal delivery. Thromb Res 2011; 128:62-7. [DOI: 10.1016/j.thromres.2011.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 12/28/2010] [Accepted: 01/31/2011] [Indexed: 11/18/2022]
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Schlagenhauf A, Schweintzger S, Birner-Gruenberger R, Leschnik B, Muntean W. Newborn platelets: lower levels of protease-activated receptors cause hypoaggregability to thrombin. Platelets 2010; 21:641-7. [PMID: 20807173 DOI: 10.3109/09537104.2010.504869] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Newborn platelets show in vitro hypoaggregability to thrombin. Sensitivity of platelets to such a potent agonist is crucial for a functional clot formation. Nevertheless, newborns have an excellent hemostasis. We wanted to investigate the reason for this impairment by comparatively analysing levels of receptors known to be involved in thrombin signaling in newborn and adult platelets. Platelets of adult and cord blood were isolated, washed, and lysed. Resulting protein samples were separated by SDS-PAGE and blotted on nitrocellulose membranes. Receptors were visualized using immunodetection and evaluated densitometrically. Thrombin receptor activating peptide induced platelet aggregation was measured in citrated whole blood on a Multiplate analyzer. Statistical analysis was performed using SPSS 16.0. Significantly lower levels of protease-activated receptors (PAR1, PAR4) and higher levels of glycoprotein Ibα (GPIbα) were found in newborn platelets as compared to adult platelets. Platelet aggregation was lower in newborn samples than in adult controls and values correlated with the corresponding PAR levels. Our results suggest that lower levels of protease-activated receptors contribute to the poor thrombin induced aggregation observed with newborn platelets, which can not be compensated by higher levels of GPIbα.
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Affiliation(s)
- A Schlagenhauf
- Department of Pediatrics, Medical University of Graz, Austria
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