Characterization of negatively charged phospholipids and cell origin of microparticles in women with gestational vascular complications

Introduction: Gestational vascular complications (GVC) are a major cause of maternal and fetal morbidity which can be potentially reduced by LMWH. Microparticles (MPs) are involved in thrombosis and inflammation. However, characterization and role of MPs in GVC have not been elucidated. Materials and Methods: MPs were isolated from non-pregnant women, healthy pregnant women, women with GVC (hypertension or preeclamptic toxemia (PET)) and women with a history of pregnancy complications who were treated with LMWH. MP count, cell origin and expression of negatively charged phospholipids were evaluated. Results: Total numbers of MPs were similar in the study cohorts, with a non-significant trend toward an increase in the pregnant groups, while percentage of MPs bearing negatively charged phospholipids was significantly reduced in all the pregnancy groups. Endothelial CD144-MPs were elevated in the GVC groups compared to the healthy pregnant cohort. Endothelial CD31 +/CD41-MPs were decreased in the LMWH group compared to women with PET. Percentage of placental trophoblast MPs was similar in all pregnancy groups and platelet MPs were reduced in healthy pregnant compared to non-pregnant women. Notably, percent of MPs bearing negatively charged phospholipids correlated only with platelet MPs, but not with endothelial, trophoblast or leukocyte MPs. Conclusion(s): Presence of negatively charged phospholipids cannot be considered universal characteristics of MPs in pregnancy. MPs may reflect the vascular injury characterizing GVC pathology.