Extravillous trophoblast invasion in placenta accreta is associated with differential local expression of angiogenic and growth factors: a cross-sectional study.

OBJECTIVE: Placenta accreta is clinically associated with maternal uterine scar. Our objective was to investigate the biochemical contribution of maternal scarring to hyperinvasive trophoblast. We hypothesised that trophoblast over-invasion in placenta accreta is associated with aberrant invasion-site signalling of growth and angiogenic factors known to be involved in wound healing and promotion of cell invasion through the epithelial to mesenchymal cellular programme. DESIGN: Cross-sectional series. SETTING: Yale-New Haven Hospital. POPULATION: Women with histologically confirmed normal and abnormal placentation. METHODS: Placental invasion site tissue sections were immunostained for endoglin and other angiogenic regulators, and transforming growth factor ß (TGFß) proteins. Maternal serum endoglin, and the vascular endothelial growth factor (VEGF) mediators hypoxia-inducible factor-1α (HIF1α) and endostatin, were assessed using immunoassay. MAIN OUTCOME MEASURES: Differences in median H-score by immunostaining and in mean serum level by immunoassay. RESULTS: By immunostaining, placenta accreta samples demonstrated intervillous endoglin shedding and increased trophoblast expression of its cleavage protein matrix metalloproteinase-14. Absent decidual HIF1α and endostatin were observed in areas of VEGF upregulation. TGFß1 was present in myocytes but not in collagen bundles into which accreta trophoblast invaded. Maternal serum endoglin decreased in praevia and accreta when corrected for gestational age. CONCLUSION: Angiogenic and growth factors at the placental invasion site are altered in accreta, both by decidual absence and within myometrial scar. We postulate this promotes the invasive phenotype of placenta accreta by activating hyperinvasive trophoblast and by dysregulating placental vascular remodelling. FUNDING: Yale Department of Obstetrics, Gynecology and Reproductive Sciences funds. TWEETABLE ABSTRACT: Placenta accreta histology shows dysregulation of angiogenic and growth factors.

The invasive phenotype of placenta accreta extravillous trophoblasts associates with loss of E-cadherin.

INTRODUCTION: Epithelial-to-mesenchymal transition (EMT) is a process of molecular and phenotypic epithelial cell alteration promoting invasiveness. Loss of E-cadherin (E-CAD), a transmembrane protein involved in cell adhesion, is a marker of EMT. Proteolysis into N- and C-terminus fragments by ADAM10 and presenilin-1 (PSEN-1) generates soluble (sE-CAD) and transcriptionally active forms. We studied the protein expression patterns of E-CAD in the serum and placenta of women with histologically-confirmed over-invasive placentation. METHODS: The patterns of expression and levels of sE-CAD were analyzed by Western blot, immunoassay, and immunoprecipitation. Tissue immunostaining for E-CAD, cytokeratin-7 (epithelial marker), vimentin (mesenchymal marker), ADAM10, PSEN-1 and ß-catenin expression were investigated in parallel. RESULTS: N-terminus cleaved 80 kDa sE-CAD fragments were present in serum of pregnant women with gestational age regulation of the circulatory levels. Women with advanced trophoblast invasion did not display circulatory levels of sE-CAD different from those of women with normal placentation. Histologically, extravillous trophoblasts (EVT) closer to the placental-myometrial interface demonstrated less E-CAD staining than those found deeper in the myometrium. These cells expressed both vimentin and cytokeratin, an additional feature of EMT. EVT of placentas with advanced invasion displayed intracellular E-CAD C-terminus immunoreactivity predominating over that of the extracellular N-terminus, a pattern consistent with preferential PSEN-1 processing. DISCUSSION: Local processing of E-CAD may be an important molecular mechanism controlling the invasive phenotype of accreta EVT.