Preeclampsia, a placental disease, is typically characterized by hypertension and proteinuria in pregnant mothers. There is a need for improved noninvasive detection and diagnosis of this condition. Extracellular microvesicles (EVs), including exosomes, are tissue specific nanoparticles released by many tissue types including the placenta into peripheral circulation. Tissue specific EVs have potential to serve as biomarkers, and their cargoes are dynamic and may reflect functional activity of their tissue counterparts. Several groups have reported an increase in whole plasma EVs in healthy pregnant women in comparison to healthy nonpregnant women, leading to the question of, how does the preeclampsia EV profile differ? In our analysis of this condition, there was no difference in total EV quantity between samples from healthy pregnant females versus those with preeclampsia. However, when we assessed for syncytiotrophoblast EVs (STEVs) using syncytin-1 as the expressed EV surface marker for placental tissue specificity, preeclampsia subjects had significantly lower circulating STEV signal, suggesting that STEV profiles have potential to serve as a noninvasive diagnostic of preeclampsia. STEVs may also play a role in the underlying preeclampsia mechanism, where STEV protein and microRNA cargoes mediate intercellular communication in maternal tissue resulting in the onset of the disease. Coordinated, detailed investigations of STEV cargoes during early pregnancy will need to be performed to understand their potential functional roles. Overall, STEV cargo profiles provide a promising insight into the diagnosis of placental injury, particularly preeclampsia, with an opportunity to noninvasively understand their functional implications.

Preeclampsia, Extracellular vesicles, Exosomes, Biomarkers, Syncytin-1