The Research On Vascular Endothelial Factor And Its Soluble Receptor-1for Patients With Unexplained Recurrent Spontaneous Abortion

BackgroundThe modern definition of recurrent spontaneous abortion (RSA) is the spontaneous loss of two or more consecutive pregnancies before20weeks of gestation. It is a common clinical problem that affects1%of couples who attempt to have children. Various factors have been identified that are thought to play a role in about50%of cases of RSA including genetic, endocrine, anatomical or autoimmune issues and infections. However the mechanism involved in the other50%of RSAs remains unexplained (Unexplained RSA). Recent studies have indicated that placental ischemia/hypoxia and endothelial dysfunction may contribute to cases of RSA. Yet the pathogenesis has not been fully elucidated. It is reported that growth and development of the fetus are critically dependent on the placental function and on vascular development. Vascular endothelial growth factor (VEGF) is a multifunctional cytokine that is produced by a variety of cell types, including the placenta. Fms-like tyrosine kinase-1(Flt-1), a transmembranous tyrosine-kinase, is a receptor for VEGF. Flt-1mRNA produces a soluble form of Flt-1by alternative splicing (sFlt-1). Soluble Flt-1(sFlt-1) is a splice variant of the Flt-1that lacks the transmembrane and cytoplasmic domains. It is a good antagonist of VEGF and can competitively inhibit the proangiogenic role of VEGF. Although sFlt-1has been demonstrated to inhibit VEGF activity, the association between sFlt-1and human disease remains unclear. Several recent experimental studies have demonstrated that VEGF and sFlt-1, contribute to the endothelial dysfunction observed in these pregnancy complications, such as hypertension, fetal growth restriction, and preeclampsia. In this study, we planned to evaluate the association between the VEGF and its soluble receptor-1, sFlt-1, in cases of recurrent spontaneous abortion. To further explose the pathogenesis of URSA. and to provide theories for the clinical prevention and treatmentPart One Association study between Vascular Endothelial Factor and its Soluble Receptor-1in pregnancy womenObjective To explores the connection between the Vascular Endothelial Growth Factor (VEGF) and its Soluble Receptor-1(sFlt-1) in pregnancy women. And to explore serum levels of VEGF and sFlt-1in diferrence early pregnancy weeks.Methods1. Case-contrl study:During the study period,50cases of no-pregnant women,50cases of normal pregnant women;50cases of URSA no-pregnant women,50cases of URSA early pregnant women were included in this study. Immunoassay for sFlt-1and VEGF serum levels of each group, respectively.2. Following up study:50cases of normal pregnant women were included in this study. Immunoassay for sFlt-1and VEGF serum levels of pregnancy4to6weeks;7to8weeks;9to10weeks;11to12weeks, respectively.Results1. The mean sFlt-1level was higher in normal pregnancy group compared to the non-pregnant group (3631.742±3000.0891pg/ml vs.1587.001±1678.2486pg/ml, P<0.05). The mean VEGF level was significantly higher in the normal pregnancy compared to the non-pregnant group (969.6429±696.9974pg/ml vs.253.8277±137.0413pg/ml, P<0.001).2. The mean sFlt1concentration in non-pregnancy women with RSA compared to the women with normal non-pregnancy (878.56±837.1065pg/ml vs.1587.001±1678.2486pg/ml, P>0.05). There is no significant difference between the two groups; The mean VEGF levels in the non-pregnancy women with RSA compared to the non-pregnant womem. There is no difference between the two groups.(242.8±236.52026pg/ml vs.253.8277±137.0413pg/ml, P>0.05). 3. In the first trimester pregnancies, the mean sFltl and VEGF concentration were highest in4to6weeks, especially in the4weeks. Then decreased and reach to certain level.ConelusionsThere is a correlation of sFlt-1and VEGF with pregnancy. In the early stages of specific placental proteins are regulated by sFlt-1and VEGF. The mean concentration of sFltl and VEGF are higher in pregnancy compared to non-pregnancy women. There is the highest level in4-6weeks in the the first trimester pregnancies, which indicates that embryo implantation and early pregnancy development occur in a relatively hypoxic environment.Part Two The Correlation Study on Vascular Endothelial Factor and its Soluble Receptor-1in Patients with Unexplained Recurrent Spontaneous AbortionObjectiveTo explores the connection between the Vascular Endothelial Growth Factor (VEGF) and its Soluble Receptor-1(sFlt-1) in pregnancy women with Unexplained Recurrent Spontaneous Abortion.Methods1. A total of35URSA patients, that subsequently miscarried and35healthy normal pregnancy women who induced abortions between weeks6and12of pregnancy were included in this study. The sFlt-1and VEGF serum levels of each group were deteced by immunoassay.2. A total of35URSA patients, that subsequently miscarried and35healthy normal pregnancy women who induced abortions between weeks6and12of pregnancy were included in this study. The expression of VEGF and sFlt-1proteins in chorionic villus tissues were deteced by immunohistochemistry.3. A total of30URSA patients, that subsequently miscarried and30healthy normal pregnancy women who induced abortions between weeks6and12of pregnancy were included in this study. The expression of expression of sFlt-1mRNA and VEGF mRNA in chorionic villus tissues were deteced by reverse transcription-polymerase chain reaction (RT-PCR).Results1. Serum level of VEGF in the URSA patients who subsequently miscarried was significantly higher than in the healthy controls (2637.5±2145.09ng/L vs.982.67±675.47ng/L P<0.001)。Serum level of sflt-1in the patients of URSA who subsequently miscarried was significantly higher than in the healthy controls (13796.67±11917.08ng/L vs.3540.67±2989.80ng/L, P<0.001)2. The expression level of VEGF protein in chorionic villus of URSA embryo growth arrest patients were significantly higher than that in normal early pregnant women (P<0.05).3. The expression level of sflt-1protein in chorionic villus of URSA embryo growth arrest patients were significantly higher than that in normal early pregnant women (P<0.05).4. The expression of sFlt-1mRNA in URSA group was found significantly increase compared with control group (38.83±2.64vs.28.53±1.70, P<0.005,). A significant increase in VEGF mRNA levels has been also detected in URSA patients when compared with control group (74.34±4.03vs.21.20±1.65, P<0.0001).ConclusionsIn this prospective study we found a high level of expression of VEGF and sFlt-1in various tissues and in the serum of URSA patients that subsequently miscarried, compared to controls. This indicates that there is a relationship between early URSA and VEGF and sFlt-1and suggests that over-expression and high levels of the sFlt-1and VEGF may be associated with the pathogenesis of URSA. Part Three The Association of VEGF Single Nucleotide Polymorphisms with the Risk of Recurrent Spontaneous Abortion of Zhuang Nationality in GuangxiObjective To investigate the association of single nucleotide polymorphisms (SNPs) in VEGF gene with the risk of recurrent spontaneous abortion of Zhuang nationality in Guangxi province.Methods110Zhuang nationality patients in Guangxi suffering recurrent spontaneous abortion and110controls were enrolled in this study. SNP of VEGF were measured by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.ResultsThe study show there is no significant difference in allele and genotype distributions of the five VEGF SNP(-2578C/A、-1154G/A、-634G/C、-460C/T and+936C/T) between URSA and controls(p>0.05). The analysis show there is no evidence of assoeiation between these polymorphisms and URSAConclusion(1) No significant evidence of assoeiation or linkage was found at any of the markers tested, indicating that the SNP of VEGF(-2578C/A、-1154G/A、-634G/C、-460C/T and+936C/T) is unlikely to play a major role in the etiology of URSA in Zhuang nationality in Guangxi.(2)Because of the highly Polymorphic of VEGF molecule, further investigation are needed to address the contribution of other SNPs and several Polymorphisms in the form of haplotypes.