Microparticles (MPs), tissue factor (TF) and tissue factor inhibitor (TFPI) in cord blood plasma. A preliminary study and literature survey of procoagulant properties of MPs.

OBJECTIVES

In the working hypothesis we assumed that the procoagulant activity of microparticles (MPs) is associated with the concentration of tissue factor (TF) and its inhibitor (TFPI), and that these three components together affect fetal hemostasis. The aim of the study was to check whether MPs are present in the cord blood, to compare their concentration with that in the maternal blood, as well as to measure the concentrations of TF antigen and TFPI antigen in the cord blood and maternal blood.

STUDY DESIGN

The study group consisted of 28 healthy parturient women who gave normal delivery, and their 28 babies. Blood from the umbilical vein was collected immediately after delivery, still prior to omphalotomy, whereas mother's blood was obtained from the antecubital vein. The concentration of MPs as well as TF antigen and TFPI antigen were measured using ELISA method.

RESULTS

The level of MPs in cord blood plasma was found to be 6.25 times higher than in the mother's blood plasma (median: 26.76 nM PS; range: 22.90-34.41 nM PS vs. median: 4.26 nM PS; range: 2.68-5.37 nM PS respectively, p=0.0022), whereas the level of TF antigen was 1.94 times higher in the fetus than in the mother (median: 238.03 pg/ml; range: 192.25-283.10 pg/ml vs. median: 122.4 pg/ml, range: 52.71-176.74 pg/ml, respectively, p=0.0012). On the other hand, the level of TFPI antigen was lower in cord blood plasma than in maternal blood plasma, accounting for 33.95% of the value noted in the mother (median: 30.04 ng/ml, range: 24.84-35.12 ng/ml vs. median: 88.48 ng/ml; range: 78.64-107.20 ng/ml, respectively, p<0.0001). There was no correlation between MP concentration and the levels of TF as well as TFPI in fetal blood and maternal blood.

CONCLUSIONS

Microparticles (MPs) are constituent components of cord blood plasma; their concentration is significantly higher than that in mother's blood plasma. In the fetus, MPs may play a role of a powerful procoagulant, thus facilitating thrombin generation (TF-dependent thrombin generation, which may take place on their surface); this hypothesis is based on literature data and our own evidence.