Platelet behaviour on von Willebrand Factor changes in pregnancy: Consequences of haemodilution and intrinsic changes in platelet function

Jonathan Cowman,Sieglinde Müllers,Antonio J Ricco,Eimear Dunne,Dermot Kenny,Adam Ralph,Fergal D Malone

doi:10.1038/s41598-017-06959-6

Jonathan Cowman, Sieglinde Müllers + Show 5 more

Open Access

https://doi.org/10.1038/s41598-017-06959-6

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Abstract

Platelet function in pregnancy is poorly understood. Previous studies of platelet function in pregnancy have used non-physiological assays of platelet function with conflicting results. This study using a physiological assay of platelet function investigated platelet interactions with von Willebrand Factor (VWF) in blood from healthy pregnant women and healthy non-pregnant controls. Blood samples (200 µl) from third-trimester pregnancies (n = 21) and non-pregnant controls (n = 21) were perfused through custom-made parallel-plate flow chambers coated with VWF under arterial shear (1,500 s−1). Multi-parameter measurements of platelet interactions with the immobilized VWF surface were recorded by digital-image microscopy and analysed using custom-designed platelet-tracking software. Platelet interactions with VWF decreased in healthy third-trimester pregnant participants relative to controls. This effect is most likely due to haemodilution which occurs physiologically during pregnancy. Interestingly, platelets in blood from pregnant participants translocated more slowly on VWF under arterial-shear conditions. These decreases in platelet translocation speed were independent of haemodilution, suggesting intrinsic changes in platelet function with pregnancy.

Highlights

During pregnancy, physiological changes occur such that platelet count falls slightly, together with a drop in haemoglobin concentration and haematocrit (HCT) as blood volume expands, typically by 40%1
Our findings demonstrate that alterations in platelet function that occur in pregnancy are due both to haemodilution and to intrinsic changes in platelet function
Dynamic platelet function on von Willebrand Factor (VWF) is reduced in healthy pregnancy

Summary

Introduction

Physiological changes occur such that platelet count falls slightly, together with a drop in haemoglobin concentration and haematocrit (HCT) as blood volume expands, typically by 40%1. To the best of our knowledge, this is the first study of pregnancy to use a multi-parameter dynamic platelet function test to examine platelet-VWF interactions under arterial shear-flow conditions.

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