Figure 2.

PP13 release from placental syncytiotrophoblast. Extracellular vesicles are cell-derived membrane particles, including exosomes (30–200 nm), microvesicles (100–1000 nm), and apoptotic bodies (>1000 nm). They are released from the placental syncytiotrophoblast layer. During normal turnover, the syncytiotrophoblast releases late-apoptotic syncytial knots (1–5 μm) as large corpuscular structure into the maternal blood. At the same time, microvesicles and exosomes are released and can pass through capillary blood vessels. PP13 cargo of microvesicles and exosomes appears on both types of these extracellular vesicles, on the surface and inside the vesicles. These vesicles may interact with various cell types (red and white blood cells or endothelial cells) and convey different messages to the maternal body.