sFlt-1 Expression Research Articles

MIF Increases sFLT1 Expression in Early Uncomplicated Pregnancy and Preeclampsia.

Insufficient immune tolerance during pregnancy is associated with pathological conditions such as preeclampsia (PE). Soluble fms-like tyrosine kinase-1 (sFLT1), which exerts a role in the late stage of PE, has shown its beneficial anti-inflammatory effects in inflammation-associated diseases. Macrophage migration inhibitory factor (MIF) was reported to upregulate sFLT1 production in experimental congenital diaphragmatic hernia. However, the placental sFLT1 expression in early uncomplicated pregnancy and whether MIF can regulate sFLT1 expression in uncomplicated and preeclamptic pregnancy are unclear. We collected first-trimester placentas and term placentas from uncomplicated and preeclamptic pregnancies to investigate sFLT1 and MIF expression in vivo. Primary cytotrophoblasts (CTBs) and a human trophoblast cell line (Bewo) were used to study the regulation of MIF on sFLT1 expression in vitro. In placentas from first-trimester pregnancy, we observed a high expression of sFLT1, specifically in extravillous trophoblasts (EVTs) and syncytiotrophoblast (STB) cells. MIF mRNA levels strongly correlated with sFLT1 expression in term placentas from preeclamptic pregnancies. In in vitro experiments, sFLT1 and MIF levels increased significantly in CTBs during their differentiation to EVTs and STBs, and MIF inhibitor (ISO-1) significantly reduced sFLT1 expression in a dose-dependent manner during this process. sFLT1 showed significant upregulation with increasing doses of MIF in Bewo cells. Our results show that sFLT1 is highly expressed at the maternal-fetal interface during early pregnancy and that MIF can increase sFLT1 expression in early uncomplicated pregnancy and PE, which suggests that sFLT1 plays an essential role in the modulation of inflammation in pregnancy.

Regulation of uterus and placenta remodeling under high estradiol levels in gestational diabetes mellitus models†.

The present study aimed to investigate the regulation of placentas and uterus remodeling and involvement of E2 in gestational diabetes mellitus (GDM). To achieve this, we established in vitro and in vivo models for GDM placentas by culturing BeWo cells under hyperglycemic concentration, and treating pregnant rats with streptozotocin (STZ). We evaluated the expression of angiogenesis-related proteins. The expression of the anti-angiogenic factor, excess placental soluble fms-like tyrosine kinase 1 (sFLT1) was increased in our in vitro GDM model compared to the control. Moreover, the expressions of placental sFLT1 and the von willebrand factor (VWF) were also significantly elevated in the placenta of STZ-treated rats. These data indicate the disruption of angiogenesis in the GDM placentas. The expression levels of connexin 43 (Cx43), a component of the gap junction and collagen type I alpha 2 chain (Col1a2), a component of the extracellular matrix, were decreased in the GDM uterus. These results suggest that uterus decidualization and placental angiogenesis are inhibited in GDM rats. Our results also showed upregulation of the expression of genes regulating E2 synthesis as well as estrogen receptors (ER) in vivo models. Accordingly, the concentration of E2 measured in the culture medium under hyperglycemic conditions, as well as in the serum and placenta of the STZ-treated rats, was significantly elevated compared to the control groups. These results suggest that the dysregulated remodeling of the placenta and uterus may result in the elevation of E2 and its signaling pathway in the GDM animal model to maintain pregnancy.

Exposure to Valproic acid (VPA) resulted in alterations in the expression of angiogenic genes (NRP-1, VEGFA, VEGFR-2 and sFlt1) and histological modifications in the placenta of mice (Mus musculus)

Valproic acid (VPA), an anti-epileptic drug (AED), has been reported to exhibit anti-angiogenic properties. This study aimed to examine the impact of VPA on the expression of NRP-1 and additional angiogenic factors, as well as angiogenesis, in mouse placenta. Pregnant mice were divided into four groups: control (K), solvent control (KP), VPA treatment at a dose of 400 mg/kg body weight (BW) (P1), and VPA treatment at a dose of 600 mg/kg BW (P2). The mice were subjected to daily treatment via gavage from embryonic day (E) 9 to E14 and E9 to E16. Histological analysis was performed to evaluate Microvascular Density (MVD) and percentage of the placental labyrinth area. In addition, a comparative analysis of Neuropilin-1 (NRP-1), vascular endothelial growth factor (VEGFA), vascular endothelial growth factor receptor (VEGFR-2), and soluble (sFlt1) expression was conducted in relation to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The results of the MVD analysis and percentage of labyrinth area in the E14 and E16 placentas indicated that the treated groups were significantly lower than the control group. The relative expression levels of NRP-1, VEGFA, and VEGFR-2 in the treated groups were lower than those in the control group at E14 and E16. Meanwhile, the relative expression of sFlt1 in the treated groups at E16 was significantly higher than in the control group. Changes in the relative expression of these genes inhibit angiogenesis regulation in the mouse placenta, as evidenced by reduced MVD and a smaller percentage of the labyrinth area.

Ergothioneine improves myocardial remodeling and heart function after acute myocardial infarction via S-glutathionylation through the NF-ĸB dependent Wnt5a-sFlt-1 pathway

Myocardial infarction (MI) remains the leading cause of cardiovascular death worldwide. Studies have shown that soluble fms-like tyrosine kinase-1 (sFlt-1) has a harmful effect on the heart after MI. However, ergothioneine (ERG) has been shown to have protective effects in rats with preeclampsia by reducing circulating levels of sFlt-1. In this study, we aimed to investigate the mechanism by which ERG protects the heart after MI in rats. Our results indicate that treatment with 10 mg/kg ERG for 7 days can improve cardiac function as determined by echocardiography. Additionally, ERG can reduce the size of the damaged area, prevent heart remodeling, fibrosis, and reduce cardiomyocyte death after MI. To explain the mechanism behind the cardioprotective effects of ERG, we conducted several experiments. We observed a significant reduction in the expression of monocyte chemoattractant protein-1 (MCP-1), p65, and p-p65 proteins in heart tissues of ERG-treated rats compared to the control group. ELISA results also showed that ERG significantly reduced plasma levels of sFlt-1. Using Glutaredoxin-1 (GLRX) and CD31 immunofluorescence, we found that GLRX was expressed in clusters in the myocardial tissue surrounding the coronary artery, and ERG can reduce the expression of GLRX caused by MI. In vitro experiments using a human coronary artery endothelial cell (HCAEC) hypoxia model confirmed that ERG can reduce the expression of sFlt-1, GLRX, and Wnt5a. These findings suggest that ERG protects the heart from MI damage by reducing s-glutathionylation through the NF-ĸB-dependent Wnt5a-sFlt-1 pathway.

Circulatory and Placental Expression of Soluble Fms-like Tyrosine Kinase- 1 and Placental Growth Factor in HIV-infected Preeclampsia.

An imbalance between angiogenic and anti-angiogenic factors plays a fundamental role in the pathogenesis of preeclampsia (PE). Studies have shown a dysregulation of sFlt-1 and placental growth factor (PlGF) in PE. However, there are differing reports on the levels of these pro-/antiangiogenic factors in HIV-infected preeclamptic and normotensive pregnancies, possibly due to highly active antiretroviral therapy (HAART) and its immune reconstitution effect. The study aimed to investigate the effect of hypertension and ARVs on circulating and placental pro- and antiangiogenic factors in HIV-infected PE. The level of sFlt-1 expression is elevated in PE compared to normal pregnancies. PlGF was altered by placental dysfunction. Antiretroviral therapy does not impact the angiogenic shift in PE development. The angiogenic imbalance evident in the circulatory system by higher sFlt-1 compared to PlGF levels is replicated in the placenta by reduced expression of PlGF receptors in comparison to sFlt-1 receptors. However, there is a lack of data that explore the relationship between HAART and anti-angiogenic factors in the placenta and the circulation of PE comorbid with HIV infection.

The correlation between serum levels and placental tissue expression of PLGF and sFLT-1 and the FIGO grading of the placenta accreta spectrum disorders

Objective This study aims to further explore the role of angiogenic vs anti-angiogenic factors in placenta accreta spectrum (PAS). Methods This cohort study included all patients with placenta previa and placenta accreta spectrum (PAS) disorders undergoing surgery at Dr. Soetomo Hospital (Academic Hospital of Universitas Airlangga, Surabaya, Indonesia) from May to September 2021. Venous blood samples for PLGF and sFlt-1 were drawn immediately prior to surgery. Placental tissue samples were taken during surgery. The FIGO grading was diagnosed intraoperatively by an experienced surgeon and confirmed by the pathologist and followed by immunohistochemistry (IHC) staining. The sFlt-1 and PLGF serum were performed by an independent laboratory technician. Results Sixty women were included in this study (20 women with placenta previa; 10 women with FIGO PAS grade 1; 8 women with FIGO PAS grade 2; 22 women with FIGO PAS grade 3). The median with 95% Confidence interval of PLGF serum values in placenta previa, FIGO grade I, grade II, and grade III were 233.68 (0.00–2434.00), 124.39 (10.42–663.68), 236.89 (18.83–418.99) and 237.31 (2.26–3101.00) (p = .736); the median values with 95% CI of serum sFlt-1 levels in placenta previa, FIGO grade I, grade II, and grade III were 2816.50 (418.00–12925.00), 2506.00 (227.50-16104.00), 2494.50 (888.52–20812.00), and 1601.00 (662.16–9574.00) (p = .037). Placental PLGF expression in placenta previa, FIGO grade 1, grade II, and grade III showed median values (with 95% CI) of 4.00 (1.00-9.00), 4.00 (2.00–9.00), 4.00 (4.00–9.00), and 6.00 (2.00–9.00) (p = .001); sFlt-1 expression median values (with 95% CI) were 6.00 (2.00–9.00), 6.00 (2.00–9.00), 4.00 (1.00–9.00), and 4.00 (1.00–9.00) (p = .004). Serum PLGF and sFlt-1 levels did not correlate with placental tissue expression (p = .228; p = .586). Conclusion There are differences in PAS's angiogenic processes ​according to the severity of trophoblast cell invasion. But there is no overall correlation between serum levels and PLGF and sFlt-1 expression in the placenta, suggesting the imbalance between angiogenic and anti-angiogenic are local mechanisms in the placental and the uterine wall.

The protective effect of magnesium sulfate on placental inflammation via suppressing the NF-κB pathway in a preeclampsia-like rat model.

Abnormal placental inflammation has a role in the pathophysiology of preeclampsia. Magnesium sulfate (MgSO4) has anti-inflammatory properties and is a fetal neuroprotective agent. MgSO4 is often used to treat severe preeclampsia; however, the specificmechanisms of action underlyingthistherapeutic effect remain unclear. The objective of this study was to investigate the effects of MgSO4 (270mg/kg) on placental inflammation in a rat model of lipopolysaccharide (LPS; 1.0µg/kg)-induced preeclampsia. Compared to normal pregnant rats, LPS-treated pregnant rats had higher blood pressure, proteinuria, and expression of the anti-angiogenic factor sFlt-1 and the pro-inflammatory factors interleukin-1β (IL-1β) and IL-12 in placental tissue. LPS-treated pregnant rats had placental insufficiency, poor fetal outcomes, and significantly decreased expression of the anti-inflammatory factors apolipoprotein E (APOE) and IL-10 in placental tissue. MgSO4 treatment had favorable effects on maternal and fetal outcomes. MgSO4 treatment improved placental function by repressing an exaggerated inflammatory response in the placenta and promoting angiogenesis via the NF-κB pathway. These findings suggest MgSO4 has a potential role in the prevention of preeclampsia and in the treatment of mild and moderate preeclampsia.

Smooth Muscle Mineralocorticoid Receptor Promotes Hypertension After Preeclampsia.

Preeclampsia is a syndrome of high blood pressure (BP) with end organ damage in late pregnancy that is associated with high circulating soluble VEGF receptor (sFlt1 [soluble Fms-like tyrosine kinase 1]). Women exposed to preeclampsia have a substantially increased risk of hypertension after pregnancy, but the mechanism remains unknown, leaving a missed interventional opportunity. After preeclampsia, women have enhanced sensitivity to hypertensive stress. Since smooth muscle cell mineralocorticoid receptors (SMC-MR) are activated by hypertensive stimuli, we hypothesized that high sFlt1 exposure in pregnancy induces a postpartum state of enhanced SMC-MR responsiveness. Postpartum BP response to high salt intake was studied in women with prior preeclampsia. MR transcriptional activity was assessed in vitro in sFlt1-treated SMC by reporter assays and PCR. Preeclampsia was modeled by transient sFlt1 expression in pregnant mice. Two months post-partum, mice were exposed to high salt and then to AngII (angiotensin II) and BP and vasoconstriction were measured. Women exposed to preeclampsia had significantly enhanced salt sensitivity of BP verses those with a normotensive pregnancy. sFlt1 overexpression during pregnancy in mice induced elevated BP and glomerular endotheliosis, which resolved post-partum. The sFlt1 exposed post-partum mice had significantly increased BP response to 4% salt diet and to AngII infusion. In vitro, SMC-MR transcriptional activity in response to aldosterone or AngII was significantly increased after transient exposure to sFlt1 as was aldosterone-induced expression of AngII type 1 receptor. Post-partum, SMC-MR-KO mice were protected from the enhanced response to hypertensive stimuli after preeclampsia. Mechanistically, preeclampsia mice exposed to postpartum hypertensive stimuli develop enhanced aortic stiffness, microvascular myogenic tone, AngII constriction, and AngII type 1 receptor expression, all of which were prevented in SMC-MR-KO littermates. These data support that sFlt1-induced vascular injury during preeclampsia produces a persistent state of enhanced sensitivity of SMC-MR to activation. This contributes to postpartum hypertension in response to common stresses and supports testing of MR antagonism to mitigate the increased cardiovascular risk in women after PE.

Reduced expression in preterm birth of sFLT-1 and PlGF with a high sFLT-1/PlGF ratio in extracellular vesicles suggests a potential biomarker.

Preterm birth may have a pathological impact on intrauterine development of the fetal brain, resulting in developmental disabilities. In this study, we examine the expression of soluble Fms-like tyrosine kinase 1 (sFLT-1) and placental growth factor (PlGF), which is one of the vascular endothelial growth factors (VEGFs), as these play a key role in angiogenesis; in particular, we examine their effect on the sFLT-1/PlGF ratio in cases of preterm birth as compared to typical pregnancies. Enzyme-linked immunosorbent assay was performed on samples of maternal-derived plasma and extracellular vesicles-exosomes (EVs-EXs) isolated at the third trimester, consisting of 17 samples from cases of preterm birth and 38 control cases. Our results showed that both sFLT-1 (P=0.0014) and PlGF (P=0.0032) were significantly downregulated in cases of preterm birth compared to controls, while the sFLT-1/PIGF ratio was significantly (P=0.0008) increased in EVs-EXs, but not in maternal plasma. Our results suggest that this reduced expression of sFLT-1 and PlGF with an elevated sFLT-1/PlGF ratio in EVs-EXs may represent a potential biomarker for prediction of PTB.

Placental DAAM2 is unaltered in preeclampsia, but upregulated by treatment with proton pump inhibitors.

Dishevelled Associated Activator Of Morphogenesis 2 (DAAM2) levels are elevated in the maternal circulation and placenta in pregnancies complicated by fetal growth restriction. However, placental DAAM2 levels in cases of preeclampsia have not previously been explored. Here, we examined placental DAAM2 in pregnancies complicated by preterm preeclampsia, and whether candidate preeclampsia therapeutics altered its expression. DAAM2 mRNA and protein levels were assessed in placental tissue from cases of preterm preeclampsia and gestation-matched controls (delivering ≤ 34weeks; qPCR and western blot respectively). Short interfering RNAs were used to silence DAAM2 in isolated primary cytotrophoblast under normoxic (8% O2) and hypoxic (1% O2) conditions, and expression of anti-angiogenic sFLT-1, angiogenic PGF, antioxidant, fetal growth, and inflammatory genes assessed. DAAM2 expression was measured in placental explant tissue from pregnancies complicated by preeclampsia, treated with three proton pump inhibitors (100µM esomeprazole, lansoprazole, and rabeprazole). DAAM2 expression was significantly reduced in preeclamptic placental tissue compared to controls, but protein production was unchanged. Silencing DAAM2 in hypoxic cytotrophoblast increased sFLT-i13 isoform expression, but did not alter sFLT-e15a or PGF expression, or sFLT-1 secretion. DAAM2 knockdown did not alter expression of antioxidant (NQO-1, TXN, GCLC), fetal growth (SPINT1), or inflammasome (NLRP3) genes. Esomeprazole and lansoprazole, but not rabeprazole, increased DAAM2 expression in placental explant tissue from cases of preeclampsia. Placental DAAM2 protein is not significantly altered in placental tissue in cases of preeclampsia, and its suppression does not alter sFLT-1 secretion. Hence, placental DAAM2 is unlikely to drive the pathogenesis associated with preeclampsia.

An endogenous inhibitor of angiogenesis downregulated by hypoxia in human aortic valve stenosis promotes disease pathogenesis

Aortic valve stenosis is the most common valve disease in the western world. Central to the pathogenesis of this disease is the growth of new blood vessels (angiogenesis) within the aortic valve allowing infiltration of immune cells and development of intra-valve inflammation. Identifying the cellular mediators involved in this angiogenesis is important as this may reveal new therapeutic targets which could ultimately prevent the progression of aortic valve stenosis. Aortic valves from patients undergoing surgery for aortic valve replacement or dilation of the aortic arch were examined both ex vivo and in vitro. We now demonstrate that the anti-angiogenic protein, soluble fms-like tyrosine kinase 1 (sFlt1), a non-signalling soluble receptor for vascular endothelial growth factor, is constitutively expressed in non-diseased valves. sFlt-1 expression was, however, significantly reduced in aortic valve tissue from patients with aortic valve stenosis while protein markers of hypoxia were simultaneously increased. Exposure of primary-cultured valve interstitial cells to hypoxia resulted in a decrease in the expression of sFlt-1. We further reveal using a bioassay that siRNA knock-down of sFlt1 in valve interstitial cells directly results in a pro-angiogenic environment. Finally, incubation of aortic valves with sphingosine 1-phosphate, a bioactive lipid-mediator, increased sFlt-1 expression and inhibited angiogenesis within valve tissue. In conclusion, this study demonstrates that sFlt1 expression is directly correlated with angiogenesis in aortic valves and the observed decrease in sFlt-1 expression in aortic valve stenosis could increase valve inflammation, promoting disease progression. This could be a viable therapeutic target in treating this disease.

Maternal cadmium exposure impairs placental angiogenesis in preeclampsia through disturbing thyroid hormone receptor signaling.

Cadmium is a ubiquitous environmental pollutant, which can increase the risk of preeclampsia. This study was designed to determine the mechanism of cadmium exposure during pregnancy impaired placental angiogenesis that was associated with the occurrence of preeclampsia. The effects of cadmium exposure on placental thyroid hormone receptor signaling were explored. JEG3 cells were treated with CdCl2 (20μM) and the Dio2 inhibitor, IOP (100μM). Cadmium levels in maternal blood and placentae were increased in preeclampsia group. Placental angiogenesis of preeclampsia was decreased with decreased expression of PLGF and VEGF and increased expression of sFlt1. Meanwhile, the expression and nuclear translocation of thyroid hormone receptor α were decreased in preeclampsia placenta, as well as the expression of Dio2, but not the expression and nuclear translocation of thyroid hormone receptor β. Furthermore, we found that cadmium exposure downregulated the expression of thyroid hormone receptor α and Dio2, but not the expression of thyroid hormone receptor β in JEG3 cells. Also, we found that cadmium exposure decreased the expression of PLGF and VEGF and increased the expression of sFlt1 in JEG3 cells. IOP pretreatment decreased the expression of PLGF and increased the expression of sFlt1. In conclusion, our results elucidated that cadmium exposure would impair placental angiogenesis in preeclampsia through disturbing thyroid hormone receptor signaling.

Abstract P104: Neutralization Of Marinobufagenin Demonstrates Efficacy In Vitro And In Vivo In Models Of Preeclampsia

Objective: Marinobufagenin (MBG), a cardiotonic steroid, is distinctly elevated in preeclampsia (preE) and may directly contribute to pathogenesis, possibly through deleterious signaling in cytotrophoblast (CTB) cells. In this study, we evaluate the effects of anti-MBG human monoclonal antibodies on cellular signaling in CTB cells and in a rat model of preE. Methods: CTB cell proliferation in response to MBG with and without anti-MBG was measured using a Cell Titer assay. Pro-angiogenic factors (VEGF and PlGF) and anti-angiogenic factors (sFlt-1 and sEng) in response to MBG with and without antibody were measured. Finally, we evaluated the lead anti-MBG antibody in comparison with the parent murine antibody in a previously described rat model of preE which recapitulates the hypertension, proteinuria, and fetal growth effects of human preE. Results: CTB cells exposed to ≥ 1 nM MBG showed decreased ( p < 0.05) proliferation, decreased secretion of VEGF and PIGF, and increased secretion of sFlt-1 and sEng. Pretreatment with anti-MBG significantly ( p < 0.05) attenuated the MBG-induced modulation of cell proliferation and expression of VEGF, PIGF, sFlt-1, and sEng. In the rat model, anti-MBG treatment normalized blood pressure, reduced proteinuria, and eliminated fetal effects. Conclusions: MBG has the potential to be a causative agent for preE as it causes dysfunction in CTB cells due to the anti-angiogenic milieu. Our study suggests that anti-MBG antibodies can bind to MBG, neutralizing it, and preventing downstream signaling in vitro. In a saline-induced rat model of preE, treatment with anti-MBG antibody was effective at normalizing blood pressure, kidney function, and fetal birth weights. These data suggest that a human monoclonal antibody with high specificity and affinity for MBG has potential as a therapeutic for preE.

Neuro-oncological Ventral Antigen 2 Regulates Splicing of Vascular Endothelial Growth Factor Receptor 1 and Is Required for Endothelial Function

Pre-eclampsia (PE) affects 2–8% of pregnancies and is responsible for significant morbidity and mortality. The maternal clinical syndrome (defined by hypertension, proteinuria, and organ dysfunction) is the result of endothelial dysfunction. The endothelial response to increased levels of soluble FMS-like Tyrosine Kinase 1 (sFLT1) is thought to play a central role. sFLT1 is released from multiple tissues and binds VEGF with high affinity and antagonizes VEGF. Expression of soluble variants of sFLT1 is a result of alternative splicing; however, the mechanism is incompletely understood. We hypothesize that neuro-oncological ventral antigen 2 (NOVA2) contributes to this. NOVA2 was inhibited in human umbilical vein endothelial cells (HUVECs) and multiple cellular functions were assessed. NOVA2 and FLT1 expression in the placenta of PE, pregnancy-induced hypertension, and normotensive controls was measured by RT-qPCR. Loss of NOVA2 in HUVECs resulted in significantly increased levels of sFLT1, but did not affect expression of membrane-bound FLT1. NOVA2 protein was shown to directly interact with FLT1 mRNA. Loss of NOVA2 was also accompanied by impaired endothelial functions such as sprouting. We were able to restore sprouting capacity by exogenous VEGF. We did not observe statistically significant regulation of NOVA2 or sFLT1 in the placenta. However, we observed a negative correlation between sFLT1 and NOVA2 expression levels. In conclusion, NOVA2 was found to regulate FLT1 splicing in the endothelium. Loss of NOVA2 resulted in impaired endothelial function, at least partially dependent on VEGF. In PE patients, we observed a negative correlation between NOVA2 and sFLT1.

Chronic Hypoxia in Ovine Pregnancy Recapitulates Physiological and Molecular Markers of Preeclampsia in the Mother, Placenta, and Offspring.

Background:Preeclampsia continues to be a prevalent pregnancy complication and underlying mechanisms remain controversial. A common feature of preeclampsia is utero-placenta hypoxia. In contrast to the impact of hypoxia on the placenta and fetus, comparatively little is known about the maternal physiology.Methods:We adopted an integrative approach to investigate the inter-relationship between chronic hypoxia during pregnancy with maternal, placental, and fetal outcomes, common in preeclampsia. We exploited a novel technique using isobaric hypoxic chambers and in vivo continuous cardiovascular recording technology for measurement of blood pressure in sheep and studied the placental stress in response to hypoxia at cellular and subcellular levels.Results:Chronic hypoxia in ovine pregnancy promoted fetal growth restriction (FGR) with evidence of fetal brain-sparing, increased placental hypoxia-mediated oxidative damage, and activated placental stress response pathways. These changes were linked with dilation of the placental endoplasmic reticulum (ER) cisternae and increased placental expression of the antiangiogenic factors sFlt-1 (soluble fms-like tyrosine kinase 1) and sEng (soluble endoglin), combined with a shift towards an angiogenic imbalance in the maternal circulation. Chronic hypoxia further led to an increase in uteroplacental vascular resistance and the fall in maternal blood pressure with advancing gestation measured in normoxic pregnancy did not occur in hypoxic pregnancy.Conclusions:Therefore, we show in an ovine model of sea-level adverse pregnancy that chronic hypoxia recapitulates physiological and molecular features of preeclampsia in the mother, placenta, and offspring.

Study on lipid nanomicelles targeting placenta for the treatment of preeclampsia

: In view of the serious clinical harm of preeclampsia and the lack of effective treatment methods, a PEG-modified lipid hybrid micelle was designed with folic acid molecule on the surface, containing siRNA, targeted delivery to the placenta, interfering the expression of sFlt-1 and treating preeclampsia. In this paper, the preparation and characterization of lipid hybrid micelles were investigated in detail, the cytology in vitro and in vivo distribution, pharmacodynamics, safety and action mechanism of the preparation were studied, which laid a foundation for gene therapy of preeclampsia.

SFlt1‐Induced Preeclampsia Enhances Cardiovascular Response to Post Partum Hypertensive Stimuli via Smooth Muscle Mineralocorticoid Receptor

BackgroundPreeclampsia (PE), a syndrome of high blood pressure (BP) and renal damage in late pregnancy, is associated with increased soluble VEGF receptor (sFlt1) and survivors have increased risk of future hypertension and cardiovascular disease.HypothesisSince smooth muscle cell mineralocorticoid receptor (SMC‐MR) can be activated by hypertensive stimuli, we hypothesized that high sFlt1 exposure during pregnancy may induce a post‐partum state of enhanced vascular sensitivity via SMC‐MR activation.Methods/ResultsA PE model was induced by transient viral expression of sFlt1 in pregnant C57Bl6 mice. Elevated serum sFlt1, BP and glomerular endotheliosis was confirmed which all resolve post‐partum. In a small cohort of women with prior PE, we confirm salt sensitivity of BP. Thus, postpartum mice were implanted with telemetric BP monitors and exposed to repeated hypertensive stimuli (high salt and subsequent AngII). Mice with prior PE had a significantly increased BP response to hypertensive stimuli. Microvascular arteries from mice after PE and hypertensive stimuli had enhanced ex vivomyogenic tone and AngII vasoconstriction. To test the direct impact of sFlt1 on SMC‐MR function, cultured SMC (Pac1) were transiently exposed to sFlt1 (24 hours on then off) to mimic the post‐PE state. SMC‐MR transcriptional activity in response to aldosterone and AngII were significantly increased after sFlt1 exposure as measured by luciferase reporter assay. Target gene expression was also enhanced after sFlt1 exposure. Finally, the role of SMC‐MR in the post‐PE phenotype was tested in vivo by PE induction in SMC‐MR‐KO vs MR‐intact littermates. Post partum, SMC‐MR‐KO mice were protected from the PE‐induced increase in aortic stiffness, microvascular myogenic tone and AngII vasoconstriction.ConclusionsFlt1‐induced PE produces a state of enhanced sensitivity to stimuli that may be mediated by increased activation of SMC‐MR. These data support the use of MR antagonists to mitigate the increased risk of cardiovascular disease in women exposed to PE.

HIF1A promotes miR-210/miR-424 transcription to modulate the angiogenesis in HUVECs and HDMECs via sFLT1 under hypoxic stress.

Angiogenesis is a critical process during human skin wound healing. However, hypoxia might lead to the dysfunction of the cellular interplay of endothelial cells and subcutaneous fibroblasts, resulting in the deregulation of angiogenesis. HIF1A is a key regulatory of the recovery of intracellular homeostasis under hypoxia. In the present study, the detailed role and mechanism of HIF1A in the angiogenesis under hypoxia were investigated. Via bioinformatic analyses on microarray profiles (GSE1041 and GSE17944), solube fms-related tyrosine kinase 1 (sFLT1, also known as sVEGFR1) and miR-210/miR-424 might be involved in HIF1A function on the angiogenesis under hypoxia in human umbilical vascular endothelium cells (HUVECs) and human dermal microvascular endothelial cells (HDMECs). In the present study, we identified sFLT1 as a downregulated gene in response to hypoxia and HIF1A overexpression in HUVECs and HDMECs. sFLT1 overexpression inhibited the capacity of migration and angiogenesis and significantly reversed the inducible effects of HIF1A on the migration and angiogenesis in both cell lines. miR-210 and miR-424 were upregulated by hypoxia and targeted sFLT1 3'-UTR to negatively modulate its expression. HIF1A modulated sFLT1 expression, VEGF signaling, and the migration and angiogenesis in HUVECs and HDMECs via miR-210/miR-424. Regarding the molecular mechanism, HIF1A bound the promoter region of miR-210 and miR-424 to activate their transcription, while miR-210/miR-424 bound sFLT1 3'-UTR to suppress its expression. In summary, HIF1A/miR-210/miR-424/sFLT1 axis modulates the angiogenesis in HUVECs and HDMECs upon hypoxic condition via VEGF signaling.

Effect of Eicosapentaenoic Acid on sFlt-1 and HIF-1α Expression Under Induced Hypoxia Conditions in Trophoblast Tumor Cell Line (JEG-3)

Background: Previous studies have shown the altered levels of long-chain polyunsaturated fatty acids (LCPUFAs) in pathological hypoxic conditions. Elevated soluble fms-like tyrosine kinase-1 (sFlt-1) expression in hypoxia plays an important role in the pathogenesis of placental as preeclampsia. Objectives: The eicosapentaenoic acid (EPA; 20:5, n-3) as LCPUFAs (omega-3) might attenuate sFlt-1 and hypoxia-inducible factor-1α (HIF-1α) expressions and secretions. Methods: JEG-3 cells were incubated with dimethyloxalylglycine (DMOG) and EPA. The SFlt-1 gene expression was determined using a real-time polymerase chain reaction. The protein secretion of sFlt-1 and HIF-1α were analyzed using Western blot. Results: The incubation of JEG-3 cells with DMOG significantly elevated messenger ribonucleic acid (mRNA) expression and protein secretion of sFlt-1 (P < 0.05); nevertheless, EPA decreased mRNA expression and protein secretion of sFlt-1 (P < 0.05). Moreover, EPA inhibited the effect of DMOG on sFlt-1 (P = 0.0361) gene expression and protein secretion and HIF-1α (P = 0.0241) protein secretion. Conclusions: The sFlt-1 expression decreased by n-3 fatty acids in trophoblast tumor cell line under induced hypoxia conditions. It seems that changes in sFlt-1 expression are mediated by the transcription factor HIF-1α.

Placental sFlt-1 Gene Delivery in Early Primate Pregnancy Suppresses Uterine Spiral Artery Remodeling.

Uterine spiral artery remodeling (SAR) is essential for promoting placental perfusion and fetal development. A defect in SAR results in placental ischemia and increase in placental expression and serum levels of the soluble fms-like tyrosine kinase-1 (sFlt-1) receptor that binds to and suppresses vascular endothelial growth factor (VEGF) bioavailability, thereby leading to maternal vascular dysfunction. We have established a nonhuman primate model of impaired SAR and maternal vascular dysfunction by prematurely elevating estradiol levels in early baboon pregnancy. However, it is unknown whether this primate model of defective SAR involves an increase in placental expression of sFlt-1, which may suppress VEGF bioavailability and thus SAR in the first trimester. Therefore, to establish the role of sFlt-1 in early pregnancy, SAR was quantified in baboons treated on days 25 through 59 of gestation (term = 184 days) with estradiol or with the sFlt-1 gene targeted selectively to the placental basal plate by ultrasound-mediated/microbubble-facilitated gene delivery technology. Placental basal plate sFlt-1 protein expression was 2-fold higher (P < 0.038) and the level of SAR for vessels > 25 µm in diameter was 72% and 63% lower (P < 0.01), respectively, in estradiol-treated and sFlt-1 gene-treated baboons than in untreated animals. In summary, prematurely elevating estradiol levels or sFlt-1 gene delivery increased placental basal plate sFlt-1 protein expression and suppressed SAR in early baboon pregnancy. This study makes the novel discovery that in elevated levels sFlt-1 has a role both in suppressing SAR in early primate pregnancy and maternal vascular endothelial function in late gestation.