title: Dynamic platelet function on von Willebrand factor is different in preterm neonates and full-term neonates: changes in neonatal platelet function.
abstract: Essentials It is unclear if platelet function differs between preterm and full-term neonates. Platelet behavior was characterized using a flow-based assay on von Willebrand Factor (VWF). Preterms had increased platelet interaction with VWF and glycoprotein Ibα expression. Platelets from preterm neonates behave differently on VWF compared to full-term neonates.
  
  
  
  Background Very low birth weight (VLBW) preterm neonates have an increased risk of hemorrhage-related morbidity and mortality as compared with their full-term counterparts. It is unclear whether platelet function differs between preterm and full-term neonates. This is partly because of the large volumes of blood required to perform standard platelet function tests, and the difficulty in obtaining such samples in neonates. Objectives This study was designed to characterize platelet behavior in neonates with a physiologic flow-based assay that quantifies platelet function in microliter volumes of blood under arterial shear. Methods Blood from VLBW preterm neonates of ≤ 32 weeks' gestation (n = 15) and full-term neonates (n = 13) was perfused under arterial shear over surface-immobilized von Willebrand factor (VWF). Platelet behavior was recorded by digital-image microscopy and analyzed. Surface expression of platelet glycoprotein (GP) Ibα and GPIIIa of VLBW preterm and full-term neonates was also measured. Results VLBW preterm neonates had increased numbers of platelets interacting with VWF, and increased GPIbα expression on the platelet surface. Despite the increased numbers of VWF interactions as reflected by flow-driven platelet translocation along the protein surface, no significant differences were observed in the numbers of platelets that adhered in a stationary fashion to VWF. Platelets from VLBW preterm neonates and those from full-term neonates behaved differently on VWF. Conclusions These differences in platelet function may contribute to the higher incidence of bleeding observed in VLBW preterm neonatal populations, or may represent a compensatory mechanism to counteract this risk of bleeding.
authors.affiliation: Biomedical Diagnostics Institute, Royal College of Surgeons in Ireland and Dublin City University, Dublin, Ireland.
authors.forename: J
authors.initials: J
authors.lastname: Cowman
authors.affiliation: Department of Neonatology, National Maternity Hospital, Dublin, Ireland.
authors.forename: N
authors.initials: N
authors.lastname: Quinn
authors.affiliation: Department of Neonatology, National Maternity Hospital, Dublin, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Geoghegan
authors.affiliation: Royal College of Surgeons in Ireland, Rotunda Hospital, Dublin, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Müllers
authors.affiliation: Biomedical Diagnostics Institute, Royal College of Surgeons in Ireland and Dublin City University, Dublin, Ireland.
authors.forename: I
authors.initials: I
authors.lastname: Oglesby
authors.affiliation: Biomedical Diagnostics Institute, Royal College of Surgeons in Ireland and Dublin City University, Dublin, Ireland.
authors.forename: B
authors.initials: B
authors.lastname: Byrne
authors.affiliation: Biomedical Diagnostics Institute, Royal College of Surgeons in Ireland and Dublin City University, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Somers
authors.affiliation: Irish Centre for High End Computing National University Ireland, Galway, Ireland.
authors.forename: A
authors.initials: A
authors.lastname: Ralph
authors.affiliation: Irish Centre for High End Computing National University Ireland, Galway, Ireland.
authors.forename: B
authors.initials: B
authors.lastname: Voisin
authors.affiliation: Biomedical Diagnostics Institute, Royal College of Surgeons in Ireland and Dublin City University, Dublin, Ireland.
authors.forename: A J
authors.initials: AJ
authors.lastname: Ricco
authors.affiliation: Department of Paediatrics, Trinity College Dublin, National Children's Hospital, Tallaght & Coombe Women's and Infant's University Hospital, Dublin, Ireland.
authors.forename: E J
authors.initials: EJ
authors.lastname: Molloy
authors.affiliation: Biomedical Diagnostics Institute, Royal College of Surgeons in Ireland and Dublin City University, Dublin, Ireland. dkenny@rcsi.ie.
authors.forename: D
authors.initials: D
authors.lastname: Kenny
mesh_terms: D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000166:cytology; D005260:Female; D005865:Gestational Age; D018056:Hemorheology; D006470:Hemorrhage / Q000097:blood; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D008297:Male; D010477:Perfusion; D015539:Platelet Activation; D010973:Platelet Adhesiveness / Q000502:physiology; D010979:Platelet Function Tests / Q000379:methods*; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism*; D011485:Protein Binding; D033081:Shear Strength; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D019038:Platelet Glycoprotein GPIb-IX Complex; D014841:von Willebrand Factor
keywords: neonate; platelet function tests; platelets; preterm infants; von Willebrand factor