Preeclampsia (PE) is a pregnancy syndrome characterized by hypertension and organ damage manifesting after 20 gestational weeks. The etiology is of multifactorial origin, where placental stress causes increased levels of placenta-derived extracellular vesicles (STBEVs) in the maternal circulation, shown to cause inflammation, endothelial activation, vasoconstriction, and anti-angiogenic activity. General endothelial dysfunction is believed to be initiated by endothelial insult during pregnancy that alters vascular function resulting in increased arterial stiffness, cardiac dysfunction, and increased risk of cardiovascular disease later in life.
Lund University researchers compared the effect of normal and PE derived STBEVs in vitro on vascular contractility of human subcutaneous arteries using wire myography. Cellular structures of exposed vessels were investigated by transmission electron microscopy. The researchers explored strategies to pharmacologically block the effects of the STBEVs on human vessels. The PE STBEVs caused significantly stronger angiotensin II-mediated contractions and extended structural damage to human subcutaneous arteries compared to normal STBEVs. These negative effects could be reduced by blocking vesicle uptake by endothelial cells, using chlorpromazine or specific antibodies towards the LOX-1 receptor. The therapeutic potential of blocking vesicle uptake should be further explored, to reduce the permanent damage caused on the vasculature during PE pregnancy to prevent future cardiovascular risk.
Blocking STBEV uptake in exposed human arterial vessels
Immunoelectron microscopy analysis using gold labeled anti-PLAP antibodies on human arterial vessels exposed in vitro to placenta-derived normal (A, C, E) or PE (B, D, F) STBEVs. (A) Exposure to normal STBEVs. Black arrows indicate PLAP-positive STBEVs. (B) Exposure to PE STBEVs. Black arrow indicates PLAP-positive STBEV. (C) Exposure to normal STBEVs in combination with chlorpromazine. (D) Exposure to PE STBEVs in combination with chlorpromazine. (E) Exposure to normal STBEVs in combination with anti-LOX-1 antibody. (F) Exposure to PE STBEVs in combination with anti-LOX-1 antibody. Scale bar = 200 nm. EC = endothelial cell; L = arterial vessel lumen.