title: Assessment of neonatal platelet adhesion, activation, and aggregation.
abstract: BACKGROUND
  Acquired and inherited bleeding disorders may present in the neonatal period with devastating lifelong effects. Diagnosing bleeding disorders in the neonatal population could aid in preventing and treating the associated complications. However, currently available platelet function testing is limited in neonates, owing to difficulties in obtaining an adequate blood volume, a lack of normal reference ranges, and an incomplete understanding of the neonatal platelet functional phenotype.
  
  
  OBJECTIVE
  To develop small-volume, whole blood platelet function assays in order to quantify and compare neonatal and adult platelet function.
  
  
  RESULTS
  Peripheral blood was obtained from healthy, full-term neonates at 24 h of life. Platelet activation, secretion and aggregation were measured via flow cytometry. Platelet adhesion and aggregation were assessed under static and flow conditions. As compared with adult platelets, peripheral neonatal platelet P-selectin expression and integrin glycoprotein IIbIIIa activation were significantly reduced in response to the G-protein-coupled receptor (GPCR) agonists thrombin receptor activator peptide-6 (TRAP-6), ADP, and U46619, and the immunoreceptor tyrosine-based activation motif (ITAM) signaling pathway agonists collagen-related peptide (CRP) and rhodocytin. Neonatal platelet aggregation was markedly reduced in response to TRAP-6, ADP, U46619, CRP and rhodocytin as compared with adult platelets. The extents of neonatal and adult platelet adhesion and aggregate formation under static and shear conditions on collagen and von Willebrand factor were similar.
  
  
  CONCLUSIONS
  As compared with adult platelets, we found that neonatal platelet activation and secretion were blunted in response to GPCR or ITAM agonists, whereas the extent of neonatal platelet adhesion and aggregate formation was similar to that of adult platelets.
authors.affiliation: Department of Biomedical Engineering, Portland, OR, USA.
authors.forename: S M
authors.identifier: http://orcid.org/0000-0002-7927-1625
authors.initials: SM
authors.lastname: Baker-Groberg
authors.affiliation: The Hemophilia Center, Oregon Health & Science University, Portland, OR, USA.
authors.forename: S
authors.initials: S
authors.lastname: Lattimore
authors.affiliation: The Hemophilia Center, Oregon Health & Science University, Portland, OR, USA.
authors.forename: M
authors.initials: M
authors.lastname: Recht
authors.affiliation: Department of Biomedical Engineering, Portland, OR, USA.
authors.forename: O J T
authors.initials: OJ
authors.lastname: McCarty
authors.affiliation: The Hemophilia Center, Oregon Health & Science University, Portland, OR, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Haley
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000737:chemistry; D000244:Adenosine Diphosphate / Q000737:chemistry; D000328:Adult; D001792:Blood Platelets / Q000166:cytology*; D002097:C-Reactive Protein / Q000737:chemistry; D002469:Cell Separation; D005434:Flow Cytometry; D006023:Glycoproteins / Q000737:chemistry; D006470:Hemorrhage / Q000097:blood; D006801:Humans; D061625:Immunoreceptor Tyrosine-Based Activation Motif; D007231:Infant, Newborn; D037181:Lectins, C-Type / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry; D015539:Platelet Activation; D010973:Platelet Adhesiveness; D010974:Platelet Aggregation; D010979:Platelet Function Tests; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000737:chemistry; D043562:Receptors, G-Protein-Coupled / Q000819:agonists; D015398:Signal Transduction
chemical_list: D006023:Glycoproteins; D037181:Lectins, C-Type; D009842:Oligopeptides; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D019038:Platelet Glycoprotein GPIb-IX Complex; D043562:Receptors, G-Protein-Coupled; C504808:Ser-Phe-Phe-Leu-Arg-Asn; C094990:adhesion receptor; D000244:Adenosine Diphosphate; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D002097:C-Reactive Protein
keywords: neonate; platelet activation; platelet adhesiveness; platelet aggregation; platelet function tests