Single extracellular vesicle analysis in human amniotic fluid shows evidence of phenotype alterations in preeclampsia.

Amniotic fluid surrounding the developing fetus is a complex biological fluid rich in metabolically active bio-factors. The presence of extracellular vesicles (EVs) in amniotic fluid has been mainly related to foetal urine. We here characterized EVs from term amniotic fluid in terms of surface marker expression using different orthogonal techniques. EVs appeared to be a heterogeneous population expressing markers of renal, placental, epithelial and stem cells. Moreover, we compared amniotic fluid EVs from normal pregnancies with those of preeclampsia, a hypertensive disorder affecting up to 8% of pregnancies worldwide. An increase of CD105 (endoglin) expressing EVs was observed in preeclamptic amniotic fluid by bead-based cytofluorimetric analysis, and further confirmed using a chip-based analysis. HLA-G, a typical placental marker, was not co-expressed by the majority of CD105+ EVs, in analogy with amniotic fluid stromal cell derived-EVs. At a functional level, preeclampsia-derived EVs, but not normal pregnancy EVs, showed an antiangiogenic effect, possibly due to the decoy effect of endoglin. Our results provide a characterization of term amniotic fluid-EVs, supporting their origin from foetal and placental cells. In preeclampsia, the observed antiangiogenic characteristics of amniotic fluid-EVs may reflect the hypoxic and antiangiogenic microenvironment and could possibly impact on the developing fetus or on the surrounding foetal membranes.

Angiogenic Properties of Placenta-Derived Extracellular Vesicles in Normal Pregnancy and in Preeclampsia.

Angiogenesis is one of the main processes that coordinate the biological events leading to a successful pregnancy, and its imbalance characterizes several pregnancy-related diseases, including preeclampsia. Intracellular interactions via extracellular vesicles (EVs) contribute to pregnancy's physiology and pathophysiology, and to the fetal-maternal interaction. The present review outlines the implications of EV-mediated crosstalk in the angiogenic process in healthy pregnancy and its dysregulation in preeclampsia. In particular, the effect of EVs derived from gestational tissues in pro and anti-angiogenic processes in the physiological and pathological setting is described. Moreover, the application of EVs from placental stem cells in the clinical setting is reported.

Selective increase of cardiomyocyte derived extracellular vesicles after experimental myocardial infarction and functional effects on the endothelium.

INTRODUCTION: Wound healing after myocardial infarction (MI) is mediated by different cell types, secreted proteins, components of the extracellular matrix (ECM) and, as increasing evidences suggest, extracellular vesicles (EVs). We aim to determine the dynamics of release and origin of EVs after MI, as well as their biological activity on endothelial cells (ECs). METHODS: MI was induced in WT mice and blood and tissues collected at baseline, 3, 15 and 30 days post-ligation for cardiac function (echocardiography) and histological evaluation. Circulating EVs subpopulations were measured by flow cytometry in mouse, and in a small cohort of patients with ST-segment elevation MI (STEMI, n = 6). In vitro, EVs were isolated from a cardiomyocyte cell line (HL1) and their function assayed on ECs. RESULTS: Leukocyte and endothelial EVs increased concomitant to inflammatory and angiogenic processes triggered by ischemia. More strikingly, cardiomyocyte EVs (connexin43+) were detected in STEMI patients and in murine MI, where a significant increase in their levels was reported at day 15 post-ischemia (p < 0.05 vs baseline). In vitro, HL1EVs induced ECs migration (p = 0.05) and proliferation (p < 0.05), but impaired tube formation. These apparent contradictory results could be partially explained by the upregulation of MMP3, and the apoptosis and senescence genes, p53 and p16, induced by HL1EVs on ECs (p < 0.05). CONCLUSIONS: MI induces the release of different EVs subpopulations, including those of cardiac origin, in a preclinical model of MI and STEMI patients. In vitro, cardiomyocyte derived EVs are able to modulate endothelial function, suggesting their active role in heart repair after ischemia.