Microparticles in newborn cord blood: slight elevation after normal delivery

Abstract

Introduction: Microparticles formed during delivery may add to the well functioning hemostasis, but also to hypercoaguability in the newborn. We wanted to investigate whether microparticles in newborn cord plasma differ from those in adult plasma in terms of concentration, procoagulant activity, and effect on thrombin generation.

Materials and methods: Three different techniques were used to analyze microparticles. To enumerate and characterize microparticles, flow cytometry and ELISA, based on the prothrombinase reaction, were used. The effect of microparticles derived tissue factor on thrombin generation was measured indirectly by calibrated automated thrombography in newborn cord and adult platelet free plasma.

Results: The flow cytometric measurements of microparticles showed no significantly increased microparticle concentration in newborn cord compared with adult plasma. By the use of ELISA a significantly increased procoagulant activity of microparticles was found in newborn cord plasma as compared to adult plasma. Initiation of thrombin generation by adding phospholipids alone suggested a higher microparticle activity in newborn cord plasma than in adult plasma.

Conclusions: Our results show a higher impact of microparticles on the hemostatic system in newborn cord plasma than in adult plasma in terms of activity, but not concentration. calibrated automated thrombography and ELISA suggest an increased microparticle activity in newborn cord plasma, but comparable results in microparticle number as determined by flow cytometry argue against strong platelet activation during birth.