Placental productions and expressions of soluble endoglin, soluble fms-like tyrosine kinase receptor-1, and placental growth factor in normal and preeclamptic pregnancies

Context: Increased production of antiangiogenic factors soluble endoglin (sEng) and soluble fms-like tyrosine kinase receptor-1 (sFlt-1) by the placenta contributes to the pathophysiology in pre-eclampsia (PE). Objective: Our objective was to determine the differences in encloglin (Eng), fms-like tyrosine kinase receptor-1 (Flt-1), and placental growth factor (PIGF) expressions between normal and PE placentas and sEng, sFlt-1, and PlGF production by trophoblast cells (TC) cultured under lowered oxygen conditions. Methods:TCs isolated from normal and PE placentas were cultured under regular(5% CO2/air) and lowered (2% O-2/5% CO2/93% N-2) oxygen conditions. sEng, sFlt-1, and PIGF productions were determined by ELISA. Protein expressions for Eng, Flt-1, and PIGF in the placental tissues were accessed by immunohistochemical staining and Western blot analysis. Deglycosylated Eng, Flt-1, and PlGF protein expressions in placental tissues were also examined. Results: PE TCs produced significantly more sEng, sFlt-1, and PIGF compared with those from normal TCs (P < 0.05). Under lowered oxygen conditions, PETCs, but not normal TCs, released more sEng and sFlt-1. In contrast, both normal and PE TCs released less PIGF (P < 0.05). Enhanced expressions of Eng and Flt-1, as well as glycosylated Eng and Flt-1, were observed in PE placentas. Immunoblot also revealed that TCs released glycosylated sFlt-1, but not sEng, in culture. Conclusions: PE TCs produce more sEng, sFlt-1, and PIGF than normal TCs. Lowered oxygen conditions promote sEng and sFlt-1, but reduce PIGF, productions by PE TCs. More glycosylated sEng and sFlt-1 are present in PE placentas. Trophoblasts release glycosylated sFlt-1, but unglycosylated sEng, in culture.