Impact of placenta-derived extracellular vesicles on endothelial function in supraphysiological maternal hypercholesterolemia

Maternal physiological hypercholesterolemia (MPH; total cholesterol (TC)≤280 mg/dL) occurs during pregnancy to support fetal growth. When TC exceeds this threshold, this condition is recognized as maternal supraphysiological hypercholesterolemia (MSPH), which is associated with endothelial dysfunction in the maternal and fetoplacental vasculature. Placenta-derived extracellular vesicles (EVs), which mediate intercellular communication during pregnancy, may contribute to MSPH by affecting endothelial cells. Aim: To characterize EVs isolated from MPH and MSPH term placentas and assess their effects on endothelial function in vitro. Methods: EVs from term MPH (n = 10) and MSPH (n = 10) placental explants were purified by differential ultracentrifugation. EVs were characterized by nanoparticle tracking analysis (NTA), transmission electron microscopy, and analysis of protein markers and content. MPH- and MSPH-EVs were labeled to assess their uptake by endothelial cells (HMEC-1). Their effects on angiogenesis, endothelial activation, endothelial nitric oxide (NO) synthase (eNOS) protein expression and NO levels were evaluated. Results: The concentration and morphology of placental EVs from MPH and MSPH were comparable. When HMEC-1 were exposed to placenta-derived EVs, MSPH-EVs increased angiogenic capacity. Intercellular adhesion molecule-1 (ICAM-1) expression was induced regardless of whether vesicles were originated from MPH or MSPH placentas. No differences were observed in eNOS expression or NO production when cells were incubated with placenta-derived EVs from both conditions. Conclusion: In our in vitro model, MSPH placenta-derived EVs adjusted angiogenesis but did not alter eNOS expression or activity in endothelial cells. Our findings suggest that placental EVs could have a protective role in the NO-associated endothelial dysfunction described in MSPH pregnancies.