Placental Release of Distinct DNA-associated Micro-particles into Maternal Circulation: Reflective of Gestation Time and Preeclampsia

BackgroundThe aim of this study was to determine whether DNA-associated micro-particles (MPs) in maternal plasma express fetal-derived human leukocyte antigen-G (HLA-G) or placental alkaline phosphatase (PLAP) and whether the levels differ between women with normotensive pregnancies and preeclampsia.MethodsDNA-associated MPs expressing HLA-G or PLAP were examined in the plasma of normal pregnant women and preeclamptic patients using flow cytometric analysis.ResultsDNA-associated HLA-G+ MPs were significantly increased in maternal plasma compared to plasma from non-pregnant controls (p < 0.005), with highest levels found in the first and second trimesters. DNA-associated PLAP+ MPs were also increased in maternal plasma compared to plasma from non-pregnant controls (p < 0.006), with highest levels in the second and third trimesters. Term preeclamptic women had higher levels of DNA-associated MPs than control pregnant women. HLA-G+ MPs from the plasma of preeclamptic women had more DNA per MP than HLA-G+ MPs from the plasma of normal pregnant women (p < 0.03).ConclusionsHLA-G+ and PLAP+ MPs increase in maternal circulation at different times during gestation. DNA amounts per HLA-G+ MP increase in preeclamptic women which might indicate dysfunctional extravillous cytotrophoblasts.