Placental Small Extracellular Vesicles Undetected in Cerebrospinal Fluid of Preeclamptic and Eclamptic Women

Circulating small extracellular vesicles (sEVs) released from the placenta carry bioactive compounds. Placental sEVs (psEVs) have been implicated as drivers of pathology in preeclampsia, a common disorder of pregnancy. This study investigates the hypothesis that psEVs are detectable in cerebrospinal fluid (CSF) during pregnancy, and are present at higher concentrations in preeclamptic and eclamptic pregnancies. Two techniques were used to search for psEVs. Firstly, the ExoCounter assay was performed on neat CSF from normotensive, preeclamptic and eclamptic pregnancies, and non-pregnant controls (n = 11, 12, 10 and 4, respectively). Quantitative PCR was used to search for psEV-associated microRNAs in the CSF of pregnant women. Neither assay found evidence of psEVs in the CSF of pregnant women, regardless of whether they had preeclampsia or eclampsia. This study suggests that psEVs do not reside in CSF during pregnancy and may be more likely to impact central nervous tissues through peripheral changes or interaction with the blood–brain barrier without crossing.