Placental barrier breakage in preeclampsia: ultrastructural evidence

It is known that the placenta acts as an immunological barrier between the mother and fetal "graft" allowing two antigenically different organisms to tolerate one another. Preeclampsia may be considered as a fetal rejection consequent to severe damage at placental endothelial and syncytiotrophoblast level. In order to verify this placental barrier damage we undertook the present study by electron microscopy.

14 placentae from preeclaptic women, and the same number of placentae from healthy controls were examined.

The results showed that endothelial cells from preeclamptic placentae express various and severe alterations, consisting of swollen and bulbous cytoplasm, degenerated inter-endothelial junctions with consequent crossing of fetal blood cells outside the vessels.

These lesions could be the ultrastructural evidence of the placental barrier breakage leading to rejective reaction we presumed to be basis of preeclampsia.