Interstitial Trophoblastic Cell Fusion and E-cadherin Immunostaining in the Placental Bed of Normal and Hypertensive Pregnancies

Abstract During their invasion of the placental bed, interstitial trophoblasts fuse to multinuclear giant cells which are thought to have lost their invasive properties. Trophoblast fusion is associated with downregulation of E-cadherin, and persistent E-cadherin expression has been linked to defective placentation in preeclampsia. Since a previous study suggested ‘premature’ giant cell formation in preeclampsia, we started with the working hypotheses that fusion is increased in hypertensive pregnancies, and that the intensity of fusion correlates with the severity of disease. Using double immunostaining for E-cadherin and cytokeratin 7/17, nuclei in interstitially invasive trophoblasts (IT) in the myometrial compartment of the placental bed from normotensive pregnancies (NT, n  = 8), gestational hypertension (GH, n  = 4), preeclampsia (PE, n  = 9), and HELLP syndrome ( n  = 5) were categorised according to the E-cadherin staining of the cell and their occurrence in single, clustered or multinuclear cells. GH and PE patients showed a higher percentage of nuclei in clustered non-fused E-cadherin-positive cells ( P P P