Trophoblast Extracellular Vesicles in Preeclampsia

The syncytiotrophoblast (STB), a fused single-cell layer of the placenta is the interface between mother and fetus. The STB constitutively releases extracellular vesicles (STBEV) directly into the maternal circulation. STBEV contain a variety of proteins and RNA which target specific cells. In preeclampsia, asymptomatic placental oxidative stress is a precursor to later multi-organ dysfunction in the mother. Increased STBEV release in preeclampsia is considered to be a consequence of syncytiotrophoblast stress. These STBEV may play a key role in signaling between fetus and mother. STBEV release in preeclampsia changes, both in terms of volume and content. In this chapter, we summarise studies to date demonstrating STBEV actions on target cells. We consider how STBEV fit into the pathophysiology of the heterogeneous syndrome of preeclampsia. We propose that STBEV are the key stress signal in preeclampsia and can explain a large part of the heterogeneity of the disease. We believe that further investigation of STBEV release, content, and actions may offer valuable insights into preeclampsia pathophysiology and potential new clinical diagnostics and therapeutic targets.