Placental exosomes and pre-eclampsia: Maternal circulating levels in normal pregnancies and, early and late onset pre-eclamptic pregnancies

Placenta. 2016 Oct;46:18-25. doi: 10.1016/j.placenta.2016.08.078. Epub 2016 Aug 21.

Abstract

Introduction and aim: Exosomes are a subtype of extracellular vesicle (20-130 nm) released by biological cells under normal and pathological conditions. Although there have been reports of circulating exosomes in normal pregnancy, the relevance of placental-derived exosomes in normal and abnormal pregnancies still needs to be elucidated. The aim of this study was to quantify total and placental-derived exosomes in maternal plasma from normal (N), early onset- and late onset-preeclampsia (PE).

Method: Plasma samples were obtained from pregnant women in the third trimester, for the isolation of exosomes by differential ultracentrifugation. Total exosomes were quantified using nanoparticle tracking analysis and immuno-reactive exosomal CD63 quantification. Placental-derived exosomes were quantified using placental alkaline phosphatase (PLAP) as a specific marker. The contribution of placental-derived exosomes to total exosomes in maternal plasma was determined by the ratio of PLAP+ exosomes to CD63+ exosomes.

Results: The concentration of total exosomes significantly increased in early onset-PE and late onset-PE compared to N (≤33 weeks) and N (≥34 weeks). The relative concentration of placental-derived exosomes significantly increased in early onset-PE but decreased in late onset-PE compared to N. The ratio of PLAP+ exosomes to total number of exosomes significantly decreased in early onset-PE and late onset-PE. A positive correlation between total and placental-derived exosomes were obtained in N (≤33 weeks: Pearson's r = 0.60, ≥34 weeks: Pearson's r = 0.67) and early onset-PE (Pearson's r = 0.51, p < 0.05) with the inverse in late onset-PE (Pearson's r = -0.62, p < 0.01).

Conclusion: The differences in the contribution of placental-derived exosomes to total exosomes in maternal circulation suggests a possible pathophysiological role of placental-derived exosomes in pre-eclampsia.

Keywords: Early onset preeclampsia; Exosomes; Late onset pre-eclampsia; Placental-derived exosomes.

MeSH terms

  • Adult
  • Case-Control Studies
  • Exosomes*
  • Female
  • Humans
  • Placenta / metabolism*
  • Pre-Eclampsia / blood*
  • Pregnancy
  • Young Adult