Differentiated reactivity of whole blood neonatal platelets to various agonists
| Autor: | S Nowak, Janusz Greger, Jacek Golanski, C. Watala, Tadeusz Pietrucha, E J drzejewska, S. Chrul, T Wojciechowski |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Adult
Blood Platelets Male Agonist medicine.medical_specialty medicine.drug_class Antithrombin III Thrombin Internal medicine medicine Humans Receptor PAR-1 Platelet Platelet activation Receptor Whole blood biology Chemistry Antithrombin Age Factors Infant Newborn Proteins Hematology General Medicine Middle Aged Flow Cytometry Platelet Activation Peptide Fragments Adenosine Diphosphate P-Selectin Endocrinology Platelet Glycoprotein GPIb-IX Complex Glycoprotein Ib biology.protein Female Prothrombin Receptors Thrombin Peptide Hydrolases medicine.drug |
| Zdroj: | Platelets. 12:99-107 |
| ISSN: | 1369-1635 0953-7104 |
| DOI: | 10.1080/09537100020032281 |
| Popis: | Neonatal platelets have been occasionally reported to show a reduced response to various agonists. The molecular mechanism(s) of such a depressed reactivity remains unclear. To further address this problem we studied neonatal platelet activation with thrombin, TRAP (thrombin receptor activating peptide, Ser-Phe-Leu-Leu-Arg-Asn-Pro-Asn-Asp-Lys-Tyr-Glu-Pro-Phe) and ADP in 42 healthy 1-2 day old neonates using a whole peripheral blood flow cytometry. The neonates did not show an increased fraction of P-selectin-positive circulating platelets, whereas the expression of GPIb (glycoprotein Ib) in resting neonatal platelets was significantly lower compared to adults. Neonatal platelets were significantly less reactive than adult platelets to thrombin and TRAP, especially at lower agonist concentrations, but not to ADP or when incubated for 1 h at room temperature. Activation of neonatal platelets with agonists resulted in a marked alterations in the expression of P-selectin, whereas the internalization of GPIb was not affected. The reduced neonatal platelet sensitivity to thrombin and TRAP was accompanied by significantly reduced ATIII (antithrombin III) and increased prothrombin fragment F(1+2) in neonatal plasma. We conclude that various receptor systems potentially able to bind thrombin are relatively insensitive in neonatal platelets. The novelty of our work is that neonatal platelet hyposensitivity is not a generalized phenomenon, but concerns only selected agonists and selected receptor systems. |
| Databáze: | OpenAIRE |
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