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Extracellular Vesicle Tissue Factor Activity Assay
Published on: December 29, 2023
High availability of intravascular tissue factor in neonates
Gerhard Cvirn1, Hans-Juergen Gruber, Martin Koestenberger
1Institute of Physiological Chemistry, Department of Pediatrics, Medical University of Graz, Austria. gerhard.cvirn@meduni-graz.at
Journal of Pediatric Hematology/Oncology
|May 8, 2007
Summary
Neonatal whole blood (WB) exhibits higher intravascular tissue factor (TF) and faster clotting times than adult WB, even after lipopolysaccharide (LPS) stimulation. This suggests TF contributes to efficient cord blood clotting in neonates.
Area of Science:
- Hematology
- Immunology
- Neonatal Medicine
Background:
- Cord blood exhibits efficient clotting despite lower procoagulatory factors.
- Intravascular tissue factor (TF) is a key initiator of blood coagulation.
- Understanding TF levels in neonatal blood is crucial for explaining hemostasis.
Purpose of the Study:
- To compare intravascular tissue factor (TF) levels in neonatal cord versus adult whole blood (WB).
- To investigate the impact of lipopolysaccharide (LPS) stimulation on TF expression and clotting in both groups.
- To elucidate the mechanisms behind efficient cord blood clotting.
Main Methods:
- Quantitative reverse transcription-polymerase chain reaction (RT-PCR) for TF mRNA expression.
- Flow-cytometric analysis (fluorescence-activated cell sorting) for surface TF antigen exposure on monocytes.
- Thrombelastography (TEG) to assess blood clotting times.
Main Results:
- Basal and LPS-induced TF mRNA expression levels were similar in cord and adult WB.
- Neonatal monocytes showed significantly higher surface TF antigen exposure in native WB.
- Cord WB exhibited significantly shorter clotting times, with a more pronounced shortening after LPS stimulation compared to adult WB.
Conclusions:
- Higher constitutive surface TF antigen on neonatal monocytes contributes to efficient cord blood clotting.
- The increased number of monocytes in neonates may enhance TF-mediated clotting.
- Intravascular TF levels play a significant role in the effective hemostasis observed in neonatal circulation.
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