Study Of HtrA4 And Syncytin-1 In Preeclampsia

Objective:Preeclampsia,a hypertensive disorder unique to pregnancy,remains a leading cause of fetal and maternal morbidity and mortality worldwide.Ten percent of women have high blood pressure during pregnancy,and preeclampsia complicates 3% to 8% of pregnancies.Its cause(s)remain unknown,and delivery remains the only definitive treatment.It is increasingly recognized that many pathophysiological processes contribute to this syndrome,it hypothesized that the progression of preeclampsia begins with shallow trophoblast invasion and disturbed remodeling of uterine spiral arteries to provide inadequate blood flow to placenta,subsequently leading increased oxidative stress and maternal endothelial dysfunction.Several circulating factors of placental origin have been found in PE,but very few have been confirmed to be produced exclusively by the placenta in association with a specific subtype of PE.High-temperature requirement factor A(HtrA)proteins belong to a unique family of multidomain serine proteases and are conserved from prokaryotes to humans.Human HtrA4,the newest member of the HtrA family,was initially reported as a serine protease associated with pregnancy.At high temperature as protease degradation the misfolded proteins in the cell cytoplasm,but at low temperature,display molecular chaperone function.Studies have shown that HtrA4,which participate in the placenta development is a early predictor of early-onset preeclampsia.The envelope gene of a identified human endogenous defective retrovirus,HERV-W,encoding a protein that we have called syncytin.Studies have indicated that syncytin may mediate placental cytotrophoblast fusion,and thus may be important in human placental morphogenesis.In addition,studies have demonstrated that the PDZ domain of HtrA4 is crucial for recognition of the SU subunit of syncytin-1.As a result,HtrA4 decreases the level of surface syncytin-1 to suppress cell-cell fusion mediated by syncytin-1.The abnormal expression of HrtA4 and Syncytin-1 may contribute to shallow trophoblast invasion in PE.The aim of the study is to evaluate the expression of HtrA4 and Syncytin-1 in maternal plasma and placental tissues,at the same time detect the value of S/D,PI,RI in uterine spiral artery blood flow,then to explore the correlation between HtrA4 and Syncytin-1 with the pathogenesis of preeclampsia,which may provide a new sight for diagnosis and treatment of PE.Methods:1 Study groups: severe preeclampsia and normal pregnant women who were admitted to the Department of Obstetrics and Gynecology,The Second Hospital of Hebei Medical University during February 2014 and May 2015.A total of 107 pregnant women were enrolled in the study,with 39 in early onset preeclampsia(E-PE),35 in late onset severe preeclampsia(LS-PE)and 33 in the control group.All women provided their written informed consent to participate in the study.Definition and classification of PE was in accordance with "the diagnosis and treatment guidelines of gestational hypertension disease(2015)".All women delivered by cesarean section(CS)were included as cases.2 Sample collection: all the object of research in the 3 days before termination of pregnancy using color doppler ultrasonic detection the umbilical artery blood flow mechanics parameters: systolic/diastolic(S/D),pulsation index(PI)and resistance index(RI).Blood samples was collected from the elbow vein before any treatment.It remained at room temperature for 2 hours and blood samples were then centrifuged by 2000 rpm,10 minutes.The supematant was collected and stored at-70℃ using for the concentration analysis of HtrA4 and Syncytin-1.All placenta tissues were obtained from pregnancies delivered by cesarean section after delivery.Placenta tissues were immediately dissected and cutted into sizes of approximately lx1x1 cm within the umbilical cord root of 3cm in maternal surface.Immunohistochemical staining was carried out using the streptavidin perosidase method after the preparation that all placenta tissues were fixed in 10% neutral buffered formalin and embedded in paraffin.3 Measurement indexes:All of the subjects,S/D,PI and RI,were measured by using color doppler ultrasonic.Enzyme-linked immunosorbent assay(ELISA)was used to measured the concentration of HtrA4 and Syncytin-1 in blood.The distribution of HtrA4,Syncytin-1 in the placenta was observed by Immunohistochemical techniques(IHC)and mean optical density value(MOD).4 Statistical analyses:SPSS version 21.0 was applied for all statistical analyses.The clinical data and the results were expressed as the mean±SD,Comparisons among groups were tested by One-Way ANOVA analysis and Student-Newman-Keuls(SNK)test,Kruskal-Wallis H Test was used if the results were homogeneity of variance or non-normal distribution.Linear correlation was assessed the linear relationship between two variables.For all tests performed,P<0.05 was considered statistically significant.Results:1 Compared with the control group,the value of S/D in E-PE was significantly higher than the normotensive pregnancy and LS-PE(P<0.05,respectively).The value of PI,RI were significantly higher than the normotensive pregnancy and LS-PE(P<0.05,respectively),and as the same with the value of PI,RI in LS-PE was also significantly higher compared with the control group(P<0.05);2 The concentration of HtrA4 in the maternal plasma was higher significantly in E-PE compared with LS-PE and normotensive pregnancy respectively(P<0.01,respectively).On the contrary,the concentration of Syncytin-1 in the maternal plasma was decreased significantly in E-PE compared to LS-PE and normotensive pregnancy respectively(P<0.01,respectively);3 HE staining: Placental villi matured well in normotensive pregnancy.The blood vessels were rich and morphology was normal in placentas villi and stroma,and the nucleuses of syncytiotrophoblast were arranged orderly on the surface of villus in normotensive pregnancy women.There were immature placental villi,arrangement in disorder of the nucleus of syncytiotrophoblasts,and the decrease,incompletion of elastic membrane,hyaline degeneration of arteriolar smooth muscle cells in LS-PE.The number of placental villi became fewer in E-PE,and there were obviously degeneration and necrosis in the villi and syncytiotrophoblast cell fusion largely on the surface of villi;4 Immunohistochemical staining: HtrA4 and Syncytin-1 were expressed in the three groups.HtrA4 was expressed in the cytotrophoblast,syncytiotrophoblast layer,and endothelial cells.The subcellular localization is in the cell membrane and cytoplasm.While Syncytin-1 was expressed in cytotrophoblast,and the subcellular localization is as same as HtrA4.Signal intensity is weak in preeclampsia,as well as the brown granules are shallow in E-PE than in LS-PE group;5 HtrA4 and Syncytin-1 were both expressed in the placenta of the three groups(E-PE,LS-PE and normotensive pregnancy):Mean optical density(MOD)values for HtrA4 in E-PE were significantly high than the normotensive pregnancy and LS-PE(P<0.05,respectively).In addition,HtrA4 in E-PE was also significantly higher compared to LS-PE(P<0.05).The expression of Syncytin-1 were significantly lower than the normotensive pregnancy and LS-PE(P<0.05,respectively),and as the same with Syncytin-1 in E-PE was also significantly lower compared to LS-PE(P<0.05);6 There is a negative correlation between HtrA4 and Syncytin-1 in maternal plasma and placenta tissue(r=-0.413,P<0.001;r=-0.649,P<0.01;respectively);7 There is a negative correlation between HtrA4 and Birth weight both in maternal plasma and placenta tissue,while a positive correlation between HtrA4 and S/D,PI,RI.A positive correlation between Syncytin-1 level and Birth Weight was found both in maternal plasma and placenta tissue,while a negative correlation between Syncytin-1 MOD level and S/D,PI,RI.Conclusions:1 The expression of HtrA4 in severe preeclampsia is unregulated.Moreover,E-PE group is higher than LS-PE.On the contrary,the expression of Syncytin-1 in severe preeclampsia is downregulated.Furthermore,E-PE group is lower than LS-PE.It suggests that HtrA4 and Syncytin-1 may involved in the pathogenesis of PE,and correlated with severity of PE.2 There is a negative correlation between the level of HtrA4 and Syncytin-1 both in maternal plasma and placenta tissue,which indicate that HtrA4 and Syncytin-1 may be have a role of antagonism in the development of PE.3 There is a negative correlation between the level of HtrA4 and the birth weight of newborns both in maternal plasma and placenta tissue in preeclampsia,and positive correlation between Htr A4 levels and S/D,PI,RI;whatever a negative correlation between the level of Syncytin-1 and the birth weight of newborns,negative correlation between Syncytin-1 levels and S/D,PI,RI.