Placental barrier breakage in preeclampsia: ultrastructural evidence

Objective: 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. Study design: 14 placentae from preeclaptic women, and the same number of placentae from healthy controls were examined. Results: 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. Conclusions: These lesions could be the ultrastructural evidence of the placental barrier breakage leading to rejective reaction we presumed to be basis of preeclampsia.