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Schlagenhauf A, Bohler S, Kunze M, Strini T, Haidl H, Erlacher M, Zieger B. Neonatal Platelets: Lower G12/13 Expression Contributes to Reduced Secretion of Dense Granules. Cells 2022; 11:cells11162563. [PMID: 36010639 PMCID: PMC9406762 DOI: 10.3390/cells11162563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/13/2022] [Accepted: 08/15/2022] [Indexed: 12/03/2022] Open
Abstract
Despite fully functional primary hemostasis, platelets of healthy neonates exhibit hypoaggregability and secretion defects, which may be adaptations to specific requirements in this developmental stage. The etiologies for reduced signal transduction vary with the type of agonist. The discovered peculiarities are lower receptor densities, reduced calcium mobilization, and functional impairments of G proteins. Reduced secretion of dense granules has been attributed to lower numbers of granules. Signaling studies with adult platelets have shown a regulating effect of the G12/13 signaling pathway on dense granule secretion via RhoA. We comparatively analyzed secretion profiles using flow cytometry and expression levels of Gq, Gi, and G12/13 using Western blot analysis in platelets from cord blood and adults. Furthermore, we evaluated Rho activation after in vitro platelet stimulation with thrombin using a pulldown assay. We observed a markedly reduced expression of the dense granule marker CD63 on neonatal platelets after thrombin stimulation. Gα12/13 expression was significantly decreased in neonatal platelets and correlated with lower Rho activation after thrombin stimulation. We conclude that lower expression of G12/13 in neonatal platelets results in attenuated activation of Rho and may contribute to reduced secretion of dense granules after exposure to thrombin.
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Affiliation(s)
- Axel Schlagenhauf
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Sheila Bohler
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, Medical Center-University of Freiburg, 79098 Freiburg im Breisgau, Germany
| | - Mirjam Kunze
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Freiburg, 79110 Freiburg im Breisgau, Germany
| | - Tanja Strini
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Harald Haidl
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Miriam Erlacher
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, Medical Center-University of Freiburg, 79098 Freiburg im Breisgau, Germany
| | - Barbara Zieger
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, Medical Center-University of Freiburg, 79098 Freiburg im Breisgau, Germany
- Correspondence: ; Tel.: +49-761-270-43000
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Heibel J, Graham EM, Mahle WT, Roux A, Graham D, Manlhiot C, Everett AD. Perioperative Metabolites Are Associated With Adverse Neonatal Congenital Heart Disease Surgical Outcomes. J Am Heart Assoc 2022; 11:e024996. [PMID: 35946448 PMCID: PMC9496308 DOI: 10.1161/jaha.121.024996] [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] [Indexed: 11/16/2022]
Abstract
Background Clinical risk factors in neonatal cardiac surgery do not fully capture discrepancies in outcomes. Targeted metabolomic analysis of plasma from neonates undergoing heart surgery with cardiopulmonary bypass was performed to determine associations with clinical outcomes. Methods and Result Samples and clinical variables from 149 neonates enrolled in the Corticosteroid Therapy in Neonates Undergoing Cardiopulmonary Bypass trial with surgical treatment for congenital heart disease between 2012 and 2016 were included. Blood samples were collected before skin incision, immediately after cardiopulmonary bypass, and 12 hours after surgery. Outcomes include composite morbidity/mortality (death, extracorporeal membrane oxygenation, cardiac arrest, acute kidney injury, and/or hepatic injury) and a cardiac composite (extracorporeal membrane oxygenation, cardiac arrest, or increase in lactate level), hepatic injury, and acute kidney injury. Targeted metabolite levels were determined by high-resolution tandem liquid chromatography and mass spectrometry. Principal component and regression analyses were used to assess associations between metabolic profiles and outcomes, with 2 models created: a base clinical model and a base model+metabolites. Of the 193 metabolites examined, 40 were detected and quantified. The first principal component, principal component 1, was composed mostly of preoperative metabolites and was significantly associated with the composite morbidity/mortality, cardiac composite, and hepatic injury outcomes. In regression models, individual metabolites also improved model performance for the composite morbidity/mortality, cardiac composite, and hepatic injury outcomes. Significant disease pathways included myocardial injury (false discovery rate, 0.00091) and heart failure (false discovery rate, 0.041). Conclusions In neonatal cardiac surgery, perioperative metabolites were associated with postoperative outcomes and improved clinical model outcome associations. Preoperative metabolite levels alone may improve risk models and provide a basis for optimizing perioperative care.
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Affiliation(s)
- Jessica Heibel
- Department of Pediatrics, Blalock-Taussig-Thomas Congenital Heart Center Johns Hopkins University Baltimore MD
| | - Eric M Graham
- Division of Pediatric Cardiology, Department of Pediatrics Medical University of South Carolina Charleston SC
| | | | - Aurelie Roux
- Molecular Determinants Core Johns Hopkins All Children's Hospital St Petersburg FL
| | - David Graham
- Molecular Determinants Core Johns Hopkins All Children's Hospital St Petersburg FL
| | - Cedric Manlhiot
- Department of Pediatrics, Blalock-Taussig-Thomas Congenital Heart Center Johns Hopkins University Baltimore MD
| | - Allen D Everett
- Department of Pediatrics, Blalock-Taussig-Thomas Congenital Heart Center Johns Hopkins University Baltimore MD
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Abstract
Neonatal megakaryopoiesis and platelet turnover form a developmentally unique pattern by generating a pool of newly released reticulated platelets from the bone marrow into the circulation. Reticulated platelets are more reactive and hyperaggregable compared to mature platelets, due to their high residual mRNA content, large size, increased expression of platelet surface receptors, and degranulation. The proportion of reticulated platelets in neonates is higher compared to that in adults. Due to the emergence of an uninhibited platelet subpopulation, the newly formed reticulated platelet pool is inherently hyporesponsive to antiplatelets. An elevated population of reticulated platelets is often associated with increased platelet reactivity and is inversely related to high on-treatment platelet reactivity, which can contribute to ischemia. Measurements of the reticulated platelet subpopulation could be a useful indicator of increased tendency for platelet aggregation. Future research is anticipated to define the distinct functional properties of newly formed reticulated or immature platelets in neonates, as well as determine the impact of enhanced platelet turnover and high residual platelet reactivity on the response to antiplatelet agents.
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Affiliation(s)
- Belay Tesfamariam
- Division of Pharmacology and Toxicology, 372792Center for Drug Evaluation and Research, Silver Spring, MD, USA
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Palma-Barqueros V, Torregrosa JM, Caparrós-Pérez E, Mota-Pérez N, Bohdan N, Llanos MDC, Begonja AJ, Sola-Visner M, Vicente V, Teruel-Montoya R, Rivera J, Ferrer-Marín F. Developmental Differences in Platelet Inhibition Response to Prostaglandin E1. Neonatology 2020; 117:15-23. [PMID: 31786577 DOI: 10.1159/000504173] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/15/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND The mechanisms underlying neonatal platelets hyporesponsiveness are not fully understood. While previous studies have demonstrated developmental impairment of agonist-induced platelet activation, differences in inhibitory signaling pathways have been scarcely investigated. OBJECTIVE To compare neonatal and adult platelets with regard to inhibition of platelet reactivity by prostaglandin E1 (PGE1). METHODS Platelet-rich plasma from umbilical cord (CB) or adult blood was incubated with PGE1 (0-1 μM). We assessed aggregation in response to adenosine diphosphate (ADP), collagen, and thrombin receptor activating peptide as well as cyclic adenosine 3'5'-monophosphate (cAMP) levels (ELISA). Gαs, Gαi2, and total- and phospho-protein kinase A (PKA) were evaluated in adult and CB ultrapure and washed platelets, respectively, by immunoblotting. RESULTS Neonatal (vs. adult) platelets display hypersensitivity to inhibition by PGE1 of platelet aggregation induced by ADP and collagen (PGE1 IC50: 14 and 117 nM for ADP and collagen, respectively, vs. 149 and 491 nM in adults). They also show increased basal and PGE1-induced cAMP levels. Mechanistically, PGE1 acts by binding to the prostanoid receptor IP (prostacyclin receptor), which couples to the Gαs protein-adenylate cyclase axis and increases intracellular levels of cAMP. cAMP activates PKA, which phosphorylates different target inhibitor proteins. Neonatal platelets showed higher basal and PGE1-induced cAMP levels, higher Gαs protein expression, and a trend to increased PKA-dependent protein phosphorylation compared to adult platelets. CONCLUSION Neonatal platelets have a functionally increased PGE1-cAMP-PKA axis. This finding supports a downregulation of inhibitory when going from neonate to adult contributing to neonatal platelet hyporesponsiveness.
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Affiliation(s)
- Verónica Palma-Barqueros
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain
| | - José Miguel Torregrosa
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain.,Praticien Hospitalier at Service d'Hématologie Oncologique, Pole Régional de Cancérologie, University Hospital of Poitiers, Poitiers, France
| | - Eva Caparrós-Pérez
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain
| | - Nerea Mota-Pérez
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain
| | - Natalia Bohdan
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain
| | | | | | - Martha Sola-Visner
- Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Vicente Vicente
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain
| | - Raúl Teruel-Montoya
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain
| | - José Rivera
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain
| | - Francisca Ferrer-Marín
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia, Spain, .,Grado de Medicina, Universidad Católica de Murcia, Murcia, Spain,
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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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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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