Figure 3.

Preeclamptic placentas TEM. (A). Villous cores with vacuolated syncytiotrophoblast and few fetal blood vessels lumen (L) containing fetal RBC and white blood cells (WBC). The maternal IVS can be seen. (B). A close-up of a villous section with numerous NPs (arrow heads) throughout the layer and also in the prolongations into the IVS (short arrows). The cytotrophoblast basement membrane is irregularly thick (BM), also contain NPs, and is separated from the EC basement membrane by abundant collagen tissue (*). (C,D) are examples of severe preeclamptic cases with thin syncytiotrophoblast and numerous clusters of pyknotic nuclei (white arrows) in the midst of vacuolated areas (*). Fetal blood vessels are few, ECs are flat and thin, and the lumen (L) is occupied by RBC. (D) shows a close-up of a syncytiotrophoblast with thin extensions (short arrows) into the IVS and numerous NPs with elongated shapes (arrow heads). (E). This is a maternal RBC in the IVS showing abundant NPs lining the surface of the cell. Free NPs are also observed (arrowhead). (F). Close-up of a fetal blood vessel lumen (L) and EC showing a ~600 nm irregular exosome decorated with numerous NPs (arrowheads); also notice the free lumen NPs (short arrows). (G). In the same fetal blood vessel as (A), a monocytic WBC is seen at high power with its branched projections (short arrows). In the midst of the collagenous fibers, fibroblastic cell processes display numerous NPs (short arrows) (H).