Placenta-mediated complications: nucleosomes and free DNA concentrations differ depending on subtypes.

BACKGROUND Placenta-mediated pregnancy complications generate short- and long-term adverse medical outcomes for both the mother and the foetus. Nucleosomes and free DNA (fDNA) have been described in patients suffering from a wide-range of inflammatory conditions. OBJECTIVE The objective of our study was to compare nucleosomes and fDNA circulating levels during pregnancy and particularly in women developing a placenta-mediated complication according to the subtype (preeclampsia or intrauterine growth restriction) (NCT01736826). PATIENTS/METHODS A total of 115 women were prospectively included in the study across three groups: 30 healthy non-pregnant women, 50 women with normal pregnancy and 35 with a complicated pregnancy. Blood samples were taken up to every four weeks for several women with normal pregnancy and nucleosomes and fDNA were quantified using ELISA and quantitative polymerase chain reaction respectively. RESULTS We show that nucleosomes and fDNA concentrations significantly increase during normal pregnancy, with concentrations at delivery differing between the two groups. Interestingly, we show that concentrations differ according to the type of placenta-mediated complications, with higher levels in preeclampsia compared to intrauterine growth restriction. CONCLUSIONS These data suggest that nucleosomes and fDNA may be additional actors participating in placenta-mediated pregnancy complications.