Selective deficit of angiogenic growth factors characterises pregnancies complicated by pre-eclampsia

Establishment of the fetal-maternal interface: developmental events in human implantation and placentation

Early pregnancy is a complex and well-orchestrated differentiation process that involves all the cellular elements of the fetal-maternal interface. Aberrant trophoblast-decidual interactions can lead to miscarriage and disorders that occur later in pregnancy, including preeclampsia, intrauterine fetal growth restriction, and preterm labor. A great deal of research on the regulation of implantation and placentation has been performed in a wide range of species. However, there is significant species variation regarding trophoblast differentiation as well as decidual-specific gene expression and regulation. Most of the relevant information has been obtained from studies using mouse models. A comprehensive understanding of the physiology and pathology of human implantation and placentation has only recently been obtained because of emerging advanced technologies. With the derivation of human trophoblast stem cells, 3D-organoid cultures, and single-cell analyses of differentiated cells, cell type-specific transcript profiles and functions were generated, and each exhibited a unique signature. Additionally, through integrative transcriptomic information, researchers can uncover the cellular dysfunction of embryonic and placental cells in peri-implantation embryos and the early pathological placenta. In fact, the clinical utility of fetal-maternal cellular trafficking has been applied for the noninvasive prenatal diagnosis of aneuploidies and the prediction of pregnancy complications. Furthermore, recent studies have proposed a viable path toward the development of therapeutic strategies targeting placenta-enriched molecules for placental dysfunction and diseases.

FtMt reduces oxidative stress-induced trophoblast cell dysfunction via the HIF-1α/VEGF signaling pathway

BACKGROUND

Preeclampsia (PE) is a complication of pregnancy that causes long-term adverse outcomes for the mother and fetus and may even lead to death. Oxidative stress caused by the imbalance of oxidants and antioxidants in the placenta has been considered as one of the key mechanisms of preeclampsia (together with inflammation, etc.), in which the placental mitochondria play an important role. The expression of hypoxia-inducible factor-1 (HIF-1α) and vascular endothelial growth factor (VEGF) is known to be increased in patients with PE. Mitochondrial ferritin (FtMt) is known to protect the mitochondria from oxidative stress, although its specific role in PE remains unclear.

METHODS

We used qRT-PCR and western blotting to detect the expression levels of FtMt, HIF-1α, and VEGF in placental tissues from patients with PE. Human chorionic trophoblast cells were also administered with hypoxia treatment, followed by the detection of cell proliferation, invasion and angiogenic capacity by CCK8, Transwell, and endothelial cell angiogenesis assays; we also detected the expression of HIF-1α and VEGF in these cells. Finally, overexpression or inhibitory FtMt lentiviral vectors, along with negative control vectors, were constructed and transfected into hypoxia-treated human chorionic trophoblast cells; this was followed by analyses of cell function.

RESULTS

The expression levels of FtMt, HIF-1α and VEGF in the PE group were higher than those in the control group (P < 0.05). Following hypoxia, there was an increase in the expression levels of HIF-1α and VEGF protein in trophoblast cells. There was also an increase in invasion ability and vascular formation ability along with a reduction in cell proliferation ability. These effects were reversed by transfecting cells with the knockout FtMt lentivirus vector. The differences were statistically significant.

CONCLUSION

Analyses showed that FtMt plays a key role in the vascular regulation of PE trophoblast cells after hypoxia possibly acting via the HIF-1α/VEGF signaling pathway. These results provide us an enhanced understanding of the pathogenesis of PE and suggest that the HIF-1α/VEGF signaling pathway represents a new target for the treatment of PE.

Similar Pro- and Antiangiogenic Profiles Close to Delivery in Different Clinical Presentations of Two Pregnancy Syndromes: Preeclampsia and Fetal Growth Restriction

The purpose of this study was to evaluate serum levels of anti- and pro-angiogenic substances measured using enzyme-linked immunosorbent assays and their ratios in pregnancies complicated by different clinical subsets of placental ischemic syndrome: preeclampsia and/or fetal growth restriction. A prospective case-control study was performed consisting of 77 singleton pregnancies complicated by preeclampsia, preeclampsia with concurrent fetal growth restriction (FGR), and isolated normotensive FGR pairwise matched by gestational age with healthy pregnancies. The entire study cohort was analyzed with respect to adverse pregnancy outcomes that occurred. In all investigated subgroups, placental growth factor (PlGF) was lower and soluble endoglin (sEng), the soluble fms-like tyrosine kinase-1-sFlt-1/PlGF and sFlt-1*sEng/PlGF ratios were higher than in the control group. The differences were most strongly pronounced in the PE with concurrent FGR group and in the sFlt-1/PlGF ratio. The highest sFlt-1 values in preeclamptic patients suggest that this substance may be responsible for reaching the threshold needed for PE to develop as a maternal manifestation of ischemic placental disease. The FGR is characterized by an elevated maternal sFlt-1/PlGF ratio, which boosts at the moment of indicated delivery due to fetal risk. We concluded that angiogenic imbalance is reflective of placental disease regardless of its clinical manifestation in the mother, and may be used as support for the diagnosis and prognosis of FGR.

Cytokine conjugates to elastin-like polypeptides

Cytokines are a group of pleiotropic proteins which are crucial for various biological processes and useful as therapeutics. However, they usually suffer from the poor stability, extreme short circulation half-life, difficulty in high-yield and large-scale production and side effects, which greatly restricts their applications. Over the past decades, conjugation of cytokines with elastin-like polypeptides (ELPs), a type of promising biomaterials, have showed great potential in solving these challenges due to ELP's thermal responsiveness, excellent biocompatibility and biodegradability, non-immunogenicity, and ease of design and control at the genetic level. This review presents recent progress in the design and production of a variety of ELP conjugated cytokines for extended circulation, enhanced stability, increased soluble protein expression, simplified purification, improved drug delivery, and controlled release. Notably, the unique thermoresponsive properties of cytokine-ELP conjugates make it possible to self-assemble into micelles with drastically extended circulatory half-life for targeted delivery or to in situ form drug depots for topical administration and controlled release. The challenges and issues in the emerging field are further discussed and the future directions are pointed out at the end of this review.

Long-term observational study of renal outcome after preeclampsia: Role of soluble fms-like tyrosine kinase-1(sFlt-1)/ placental growth factor (PlGF) and endoglin

Introduction

Preeclampsia (PE) is an important complication of pregnancy that can lead to chronic kidney disease. Soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), the sFlt-1/PlGF ratio and endoglin are biomarkers for the differential diagnosis of PE and other diseases. We aimed to explore the correlation of these biomarkers with long-term renal function, blood pressure and the urine albumin/creatinine ratio (UACR) in PE patients.

Methods

34 patients with PE were enrolled. Blood samples for sFlt-1, PlGF, endoglin and the urine albumin/creatinine ratio (UACR) were collected at the time of PE diagnosis (at 35–40 weeks’ gestational age (GA) (87.50% of cases). After delivery, the patients were followed up at three months and one year to assess blood pressure, renal function and the UACR.

Results

Thirty-four PE patients were included, and 17 completed the study. The estimated glomerular filtration rate (eGFR) decreased significantly at three months and one year after follow-up (128.20 ± 10.34 to 120.75 ± 10.166 ml/min/1.73 m² (p = 0.001) at three months and 126.71 ± 9.948 to 114.29 ± 11.274 ml/min/1.73 m² (p < 0.001) at one year). The endoglin level correlated significantly with the eGFR level during PE, but there was no correlation of any biomarker with eGFR, blood pressure, or the UACR at one year.

Conclusion

Women with PE have a reduction of eGFR at three months and one year after the diagnosis of PE. Only endoglin is correlated with eGFR antepartum; however, it is not correlated with long-term renal function, blood pressure or the UACR.

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Preeclampsia has been suggested to increase the risk of kidney problems.

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The soluble endoglin level and sFlt-1:PlGF ratio can predict early and late-onset preeclampsia.

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Analysis of angiogenic factors may be associated with long term renal function.

Identification of Biomarkers for Preeclampsia Based on Metabolomics

Background

Preeclampsia (PE) is a significant cause of maternal and neonatal morbidity and mortality worldwide. However, the pathogenesis of PE is unclear and reliable early diagnostic methods are still lacking. The purpose of this review is to summarize potential metabolic biomarkers and pathways of PE, which might facilitate risk prediction and clinical diagnosis, and obtain a better understanding of specific metabolic mechanisms of PE.

Methods

This review included human metabolomics studies related to PE in the PubMed, Google Scholar, and Web of Science databases from January 2000 to November 2021. The reported metabolic biomarkers were systematically examined and compared. Pathway analysis was conducted through the online software MetaboAnalyst 5.0.

Results

Forty-one human studies were included in this systematic review. Several metabolites, such as creatinine, glycine, L-isoleucine, and glucose and biomarkers with consistent trends (decanoylcarnitine, 3-hydroxyisovaleric acid, and octenoylcarnitine), were frequently reported. In addition, eight amino acid metabolism-related, three carbohydrate metabolism-related, one translation-related and one lipid metabolism-related pathways were identified. These biomarkers and pathways, closely related to renal dysfunction, insulin resistance, lipid metabolism disorder, activated inflammation, and impaired nitric oxide production, were very likely to contribute to the progression of PE.

Conclusion

This study summarized several metabolites and metabolic pathways, which may be associated with PE. These high-frequency differential metabolites are promising to be biomarkers of PE for early diagnosis, and the prominent metabolic pathway may provide new insights for the understanding of the pathogenesis of PE.

Growth arrest-specific protein-6/AXL signaling induces preeclampsia in rats†

Preeclampsia (PE) is a complicated obstetric complication characterized by increased blood pressure, decreased trophoblast invasion, and inflammation. The growth arrest-specific 6 (Gas6) protein is known to induce dynamic cellular responses and is elevated in PE. Gas6 binds to the AXL tyrosine kinase receptor and AXL-mediated signaling is implicated in proliferation and migration observed in several tissues. Our laboratory utilized Gas6 to induce preeclamptic-like conditions in pregnant rats. Our objective was to determine the role of Gas6/AXL signaling as a possible model of PE. Briefly, pregnant rats were divided into three groups that received daily intraperitoneal injections (from gestational day 7.5 to 17.5) of phosphate buffered saline (PBS), Gas6, or Gas6 + R428 (an AXL inhibitor administered from gestational day 13.5 to 17.5). Animals dispensed Gas6 experienced elevated blood pressure, increased proteinuria, augmented caspase-3-mediated placental apoptosis, and diminished trophoblast invasion. Gas6 also enhanced expression of several PE-related genes and a number of inflammatory mediators. Gas6 further enhanced placental oxidative stress and impaired mitochondrial respiration. Each of these PE-related characteristics was ameliorated in dams and/or their placentae when AXL inhibition by R428 occurred in tandem with Gas6 treatment. We conclude that Gas6 signaling is capable of inducing PE and that inhibition of AXL prevents disease progression in pregnant rats. These results provide insight into pathways associated with PE that could be useful in the clarification of potential therapeutic approaches.

A Role for RAGE in DNA Double Strand Breaks (DSBs) Detected in Pathological Placentas and Trophoblast Cells

Impaired DNA damage responses are associated with several diseases, including pregnancy complications. Recent research identified an ATM-kinase dependent function for the nuclear isoform of the receptor for advanced glycation end-products (RAGE) during double strand break (DSB)-repair. RAGE contributes to end-resectioning of broken DNA sites by binding with the MRE11-Rad50-Nbs1 (MRN) complex. Placental research is limited regarding the impact of genomic instability and the mechanism for potential repair. We tested the hypothesis regarding the involvement of RAGE during the repair of placental DNA-DSBs. We first identified that the pregnancy complications of PE and preterm labor (PTL) experience loss of genomic integrity and an in vitro trophoblast cell model was used to characterize trophoblast DSBs. Colocalized immunofluorescence of γ-H2AX and RAGE support the potential involvement of RAGE in cellular responses to DNA-DSBs. Immunoblotting for both molecules in PE and PTL placenta samples and in trophoblast cells validated a connection. Co-immunoprecipitation studies revealed interactions between RAGE and pATM and MRE11 during DNA-DSBs. Reduced cellular invasion confirmed the role of genomic instability in trophoblastic function. Collectively, these experiments identified genomic instability in pregnancy complications, the impact of defective DNA on trophoblast function, and a possible RAGE-mediated mechanism during DNA-DSB repair.

Differential regulation of a placental SAM68 and sFLT1 gene pathway and the relevance to maternal vitamin D sufficiency

OBJECTIVE

The goal of this study was to determine if an axis of placental gene expression associated with early onset and severe preeclampsia (EOSPE) was operative in term pregnancy and correlated with vitamin D sufficiency.

METHODS

qPCR analysis of NKX2-5, SAM68, sFLT1 and membrane bound VEGFR1/FLT1 mRNA expression was conducted in placentas from 43 subjects enrolled in a vitamin D3 pregnancy supplementation trial. Pair-wise rank order correlations between patient-specific gene expression levels were calculated, and their relationship to maternal 25(OH)D status was assessed by a two-sample Wilcoxon test. Additionally, we probed the mechanistic link between SAM68 and sFLT1 using siRNA depletion in a human trophoblast cell line model.

RESULTS

Positive and highly significant correlations were found between SAM68 vs. sFLT1 and SAM68 vs. FLT1 expression levels, as were significant and differential correlations between the expression of these genes and perinatal 25(OH)D status. The variability when stratified by race/ethnicity was qualitatively distinct from those previously observed in EOSPE. Mechanistic studies confirmed a functional role for SAM68 protein in the regulation of sFLT1 expression. NKX2-5 expression was not significantly correlated with sFLT1 or SAM68 expression in these samples, suggesting that its expression may be significant at earlier stages of pregnancy or be restricted to pathological settings.

CONCLUSIONS

These data further support our overarching hypothesis that SAM68 expression is a key determinant of VEGFR1 isoform expression in the placenta, and provide additional insights into how this gene pathway may be differentially deployed or modified in normal and pathological pregnancies.

Serum levels of vasoactive factors in HIV-infected pre-eclamptic women on HAART

In South Africa, pre-eclampsia (PE) and human immunodeficiency virus (HIV) infection are major causes of pregnancy-related deaths. This study aimed to measure serum levels of endothelin-1 (ET-1), endothelial nitric oxide synthase (eNOS), soluble fms-like tyrosine kinase 1 (sFlt-1), soluble endoglin (sEng) and placental growth factor (PlGF) in HIV-infected highly active antiretroviral therapy (HAART)-treated and HIV-uninfected PE and normotensive women to ascertain if HIV/HAART alters their concentrations. Mean sFlt-1 levels were significantly up-regulated in the PE (HIV-uninfected 4.39 ± 1.29; HIV-infected 5.10 ± 1.10 ng/ml) compared to normotensive women (HIV-uninfected 2.59 ± 0.83; HIV-infected 2.20 ± 0.85 ng/ml). Mean PlGF levels were significantly lower in HIV-uninfected PE vs. HIV-infected normotensive women (29.69 ± 4.47 pg/ml vs. 32.86 ± 6.46 pg/ml; p = .002). In conclusion, PE women with HIV exhibited significantly low serum PlGF, ET-1 and eNOS levels. Infection with HIV may have further increased the sFlt-1 levels.IMPACT STATEMENTWhat is already known on this subject? In PE, the numerous identified local and circulating bioactive factors differed in concentrations when compared to normal pregnancy.What do the results of this study add? PE women with HIV exhibited significantly low serum PlGF, ET-1 and eNOS levels as well as increased levels of sFlt-1.What are the implications of these findings for clinical practice and/or further research? Understanding the link between PE, HIV and HAART during pregnancy will improve prognosis, management and treatment strategies for women clinically.

Vascular endothelial growth factor C/A 2578 gene polymorphism and umbilical artery Doppler in preeclamptic women

INTRODUCTION

Preeclampsia is strongly associated with placental hypoperfusion. Genetic factors have an impact on the pathogenesis of preeclampsia. The aim is to assess the association of Vascular Endothelial Growth Factor (C2578A) gene polymorphism with the occurrence and severity of preeclampsia and the umbilical artery Doppler changes among preeclamptic women.

MATERIALS AND METHODS

This case-control study was conducted in clinical and Chemical pathology and Obstetrics departments in Beni- Suef University, Egypt. Two hundred and ninety pregnant women above 20 weeks gestational age until delivery were divided into 2 main groups. The patient group included 145 preeclamptic women who were further sub grouped according to the severity of preeclampsia into 82 severe and 63 mild cases. Control group included 145 normotensive pregnant women. Our primary outcome was detection of VEGF C 2578 A gene mutations by a polymerase chain reaction. A secondary outcome was Doppler changes in the pulsatility index of the umbilical artery compared with VEGF genotypes.

RESULTS

Our study showed that VEGF C 2578 A genotype and alleles frequencies were not related to the occurrence of preeclampsia (p-value 0.513 and 0.549, respectively), odds ratio (95%CI) 1.154 (0.724-1.848). Mild preeclamptic cases showed no significance comparing VEGF genotypes studied and pulsatility index of the umbilical artery. However, severe cases showed p-value < 0.0001.

CONCLUSION

We concluded that VEGF 2578C/A polymorphism had no association with the occurrence of preeclampsia in studied groups, whereas there was a significant relationship among severe cases between CA and CC genotypes and pulsatility index of the umbilical artery.

The orphan nuclear receptor NUR77 promotes trophoblast invasion at early pregnancy through paracrine placental growth factor

NR4A1 (NUR77) is an orphan nuclear receptor that has been implicated in both cell survival and apoptosis. However, the role of NUR77 in trophoblast function during early placenta development has not been fully elucidated. In this study, we showed that NUR77 expression was significantly lower in the villi of the recurrent miscarriage (RM) group compared to that in the healthy controls (HCs) group. We used immunohistochemistry and found that NUR77 was highly expressed in human placental villi during early pregnancy, especially in syncytiotrophoblast (STB), and was expressed at a much lower level in STB from the RM group than in those from HC group. Western blotting data further confirmed that NUR77 was highly expressed in primary human term placental STB and the FSK-induced BeWo cell line. Moreover, antibody array screening and ELISA revealed that NUR77 promoted significant placental growth factor (PGF) expression during trophoblast fusion. Ectopic overexpression and knockdown experiments demonstrated that PGF was a novel downstream target of NUR77, and serum PGF expression correlated positively with trophoblast NUR77 mRNA levels in HCs and RM patients. Importantly, bioinformatics analysis identified two NUR77 binding sites in the PGF promoter region, and chromatin immunoprecipitation (ChIP) coupled with Western blotting analysis further verified that NUR77 bound directly to the PGF promoter region and promoted PGF expression. Furthermore, in a BeWo/HTR-8 co-culture system, FSK-induced BeWo-secreted PGF promoted HTR-8 cell migration and invasion, and an anti-PGF antibody reversed this effect. Collectively, these results indicated that NUR77 may play a key role in regulating trophoblast invasion at early pregnancy. KEY MESSAGES: NUR77 expression was significantly decreased in the syncytiotrophoblast of the recurrent miscarriage group compared to that in the healthy control group. NUR77 promoted PGF expression during trophoblast fusion. ChIP and western blotting experiments verified that NUR77 bound directly to the PGF promoter region and activated PGF expression in trophoblast. Trophoblast-derived PGF promoted HTR-8 cell migration and invasion in a cell co-culture system.

Paternal Determinants in Preeclampsia

Preeclampsia is a condition associated with high rates of maternal-fetal morbidity and mortality. It usually occurs in 3–10% of nulliparous women and 18% of previously affected women. Different lines of evidence have demonstrated the role of the father in the onset of preeclampsia. The placenta is the cornerstone of preeclampsia and poses important paternal genetic determinants; in fact, the existence of a “paternal antigen” has been proposed. Nulliparity is a well-known risk factor. Change of partner to a woman without history of preeclampsia increases the risk; however, this change decreases in women with history of the condition. High interval between pregnancies, short sexual intercourse before pregnancy, and conception by intracytoplasmic sperm injection suggest a limited exposure to the so-called paternal antigen. A man who was born from a mother with preeclampsia also increases the risk to his partner. Not only maternal but also paternal obesity is a risk factor for preeclampsia. Fetal HLA-G variants from the father increased the immune incompatibility with the mother and are also significantly associated with preeclampsia in multigravida pregnancies. An analysis of a group of Swedish pregnant women showed that the risk for preeclampsia is attributable to paternal factors in 13% of cases, which could be related to genetic interactions with maternal genetic factors. This review aimed to evaluate the evidences of the father’s contribution to the onset of preeclampsia and determine the importance of including them in future studies.

An updated view on the origin and use of angiogenic biomarkers for preeclampsia

Introduction: The last decade has seen massive efforts towards the identification and the potential use of predictive biomarkers for the pregnancy pathology preeclampsia. The angiogenic factors sFlt-1 and placental growth factor (PGF) have been in focus and have been massively supported. Areas covered: This review describes preeclampsia and intra-uterine growth restriction (IUGR), focusing on sFlt-1 and PGF, their sources during and outside pregnancy and the application of these markers in diseases outside pregnancy. Finally, the specificity of the angiogenic markers for preeclampsia is discussed. Expert commentary: The admixture of the two independent syndromes preeclampsia and IUGR has not helped in identifying the etiologies of either. Rather, it has made the search for new markers and pathways much more complicated as has the constriction on the angiogenic markers. The current markers sFlt-1 and PGF have a clear value once an adverse outcome is diagnosed but are not specific for preeclampsia. Also, they are mostly derived from the maternal vascular system rather than the placenta and are already in use as markers outside pregnancy. A new holistic approach using disease maps and interoperable workflows based on topic-related big data will help in broadening our understanding of the etiology of preeclampsia and hence, develop new markers and therapies.

Characterization of maternal plasma biomarkers associated with delivery of small and large for gestational age infants in the MIREC study cohort

Objective

Neonatal morbidity and mortality can be influenced by maternal health status. Information on maternal and fetal biomarkers of adverse health outcomes is limited. This work aims at identifying maternal biomarkers associated with low and high birth weight for gestational age groups.

Design and settings

Population-based prospective cohort study of the potential adverse health effects of exposure to environmental contaminants on pregnancy and infant health.

Methods

Third trimester maternal plasma samples (n = 1588) from a pregnancy cohort (Maternal-Infant Research on Environmental Chemicals Study, MIREC) were analyzed for changes in a target spectrum of biomarkers of vascular health (e.g., matrix metalloproteinases MMPs, vascular endothelial cell growth factor VEGF), inflammation (e.g. cellular adhesion molecules CAMs, cytokines, chemokines) by affinity-based multiplex protein array analyses. Multivariate logistic regression analyses were done to examine associations between target plasma biomarkers, maternal-infant characteristics, and birth weight outcomes assessed as small for gestational age (SGA) ≤10^th percentile and large for gestational age (LGA) ≥90^th percentile groups.

Results and outcomes

Our results revealed that maternal plasma biomarkers monocyte chemoattractant protein-1 MCP-1 (p<0.05, +ve) and VEGF (p<0.05, -ve) along with parity = 1 (p<0.01, -ve) and gestational hypertension (p<0.05, +ve) were associated with SGA births. Meanwhile, LGA was associated with maternal plasma VEGF (p<0.05, +ve) and MMP-9 (p<0.05, -ve) and gestational hypertension (p<0.01, +ve), pre-pregnancy body mass index (p<0.01, +ve), parity (p<0.05, +ve) and education (p<0.05, -ve).

Conclusions

Third trimester maternal plasma biomarkers in combination with maternal health and socioeconomic characteristics can be useful in predicting SGA and LGA outcomes. Maternal vascular health and inflammatory status may contribute to both SGA and LGA births through distinct molecular mechanisms.

ELABELA plasma concentrations are increased in women with late-onset preeclampsia

Objective: ELABELA is a newly discovered peptide hormone that appears to be implicated in the mechanisms leading to preeclampsia, independently of angiogenic factors. The aim of the current study was to investigate whether women with early- or late-onset preeclampsia have altered ELABELA plasma concentrations compared to gestational-age-matched normal pregnant women.Methods: This retrospective cross-sectional study focused on the maternal plasma samples collected from 232 women with a singleton pregnancy who were allocated into the following groups: (1) early-onset preeclampsia (<34 weeks of gestation, N = 56); (2) late-onset preeclampsia (≥34 weeks of gestation, N = 57); and (3) gestational-age-matched controls with a normal pregnancy [(<34 weeks of gestation, N = 59); (≥34 weeks of gestation, N = 60)]. ELABELA plasma concentrations were determined using a validated enzyme immunoassay.Results: (1) ELABELA plasma concentrations are higher in patients with late-onset preeclampsia compared with those from gestational-age-matched controls with a normal pregnancy [median: 7.99 ng/mL (IQR, 5.3-13.95 ng/mL) versus median: 4.17 ng/mL (IQR, 3-11.19 ng/mL), p =.001]; (2) ELABELA plasma concentrations in patients with early-onset preeclampsia do not differ from those of normal pregnant women [median: 6.09 ng/mL (IQR, 2.8-10.66 ng/mL) versus median: 4.02 ng/mL (IQR, 3.26-7.49), p = .32]; and (3) ELABELA plasma concentrations are higher in patients with late-onset preeclampsia compared to those with early-onset preeclampsia [median: 7.99 ng/mL (IQR, 5.3-13.95 ng/mL) versus median: 6.09 ng/mL (IQR, 2.8-10.66 ng/mL), p = .01].Conclusion: ELABELA plasma concentrations are higher in patients with late-onset preeclampsia than in those with a normal pregnancy. However, women with early-onset preeclampsia have similar ELABELA plasma concentrations to those with a normal pregnancy. These findings provide insight into the ELABELA axis during the human syndrome of preeclampsia. In addition, these data support the concept that different pathophysiologic mechanisms are implicated in early- and late-onset preeclampsia.

Application of metabolomics to preeclampsia diagnosis

Preeclampsia is a multifactorial disorder defined by hypertension and increased urinary protein excretion during pregnancy. It is a significant cause of maternal and neonatal deaths worldwide. Despite various research efforts to clarify pathogenies of preeclampsia and predict this disease before beginning of symptoms, the pathogenesis of preeclampsia is unclear. Early prediction and diagnosis of women at risk of preeclampsia has not markedly improved. Therefore, the objective of this study was to perform a review on metabolomic articles assessing predictive and diagnostic biomarkers of preeclampsia. Four electronic databases including PubMed/Medline, Web of Science, Sciencedirect, and Scopus were searched to identify studies of preeclampsia in humans using metabolomics from inception to March 2018. Twenty-one articles in a variety of biological specimens and analytical platforms were included in the present review. Metabolite profiles may assist in the diagnosis of preeclampsia and discrimination of its subtypes. Lipids and their related metabolites were the most generally detected metabolites. Although metabolomic biomarkers of preeclampsia are not routinely used, this review suggests that metabolomics has the potential to be developed into a clinical tool for preeclampsia diagnosis and could contribute to an improved understanding of disease mechanisms.

ABBREVIATIONS

PE: preeclampsia; sFlt-1: soluble FMS-like tyrosine kinase-1; PlGF: placental growth factor; GC-MS: gas chromatography-mass spectrometry; LC-MS: liquid chromatography-mass spectrometry; NMR: nuclear magnetic resonance spectroscopy; HMDB: human metabolome database; RCT: randomized control trial; e-PE: early-onset PE; l-PE: late-onset PE; PLS-DA: partial least-squares-discriminant analysis; CRL: crown-rump length; UtPI: uterine artery Doppler pulsatility index; BMI: body mass index; MAP: mean arterial pressure; OS: oxidative stress; PAPPA: plasma protein A; FTIR: Fourier transform infrared; BCAA: branched chain amino acids; Arg: arginine; NO: nitric oxide.

The Potential of Angiogenin as a Serum Biomarker for Diseases: Systematic Review and Meta-Analysis

Background

Angiogenin (ANG) is a multifunctional angiogenic protein that participates in both normal development and diseases. Abnormal serum ANG levels are commonly reported in various diseases. However, whether ANG can serve as a diagnostic or prognostic marker for different diseases remains a matter of debate.

Methods

Here, we performed a systematic review and meta-analysis of the literature utilizing PubMed, Web of Science, and Scopus search engines to identify all publications comparing plasma or serum ANG levels between patients with different diseases and healthy controls, as were studies evaluating circulating ANG levels in healthy populations, pregnant women, or other demographic populations.

Results

This study demonstrated that the serum ANG concentration in healthy populations was 336.14 ± 142.83 ng/ml and remained relatively stable in different populations and regions. We noted no significant differences in serum ANG levels between patients and healthy controls, except in cases in which patients suffered from cancer or cardiovascular diseases. The serum ANG concentrations were significantly higher in patients who developed colorectal cancer, acute myeloid leukemia, multiple myeloma, myelodysplastic syndromes, and heart failure than those in healthy controls.

Conclusion

ANG has the potential of being a serum biomarker for cancers and cardiovascular diseases.

Prediction and prevention of pre-eclampsia in Asian subpopulation

The benefit of the early administration of aspirin to reduce preterm pre-eclampsia among screened positive European women from multivariate algorithmic approach (ASPRE trial) has opened an intense debate on the feasibility of universal screening. This review aims to assess the new perspectives in the combined screening of pre-eclampsia in the first trimester of pregnancy and the chances for prevention using low-dose aspirin with special emphasis on the particularities of the Asian population. PubMed, CENTRAL and Embase databases were searched from inception until 15 November 2017 using combinations of the search terms: preeclampsia, Asian, prenatal screening, early prediction, ultrasonography, pregnancy, biomarker, mean arterial pressure, soluble fms-like tyrosine kinase-1, placental growth factor, pregnancy-associated plasma protein-A and pulsatility index. This is not a systematic review or meta-analysis, so the risk of bias of the selected published articles and heterogeneity among the studies need to be considered. The prevalence of pre-eclampsia and serum levels of biochemical markers in Asian are different from Caucasian women; hence, Asian ethnicity needs to be corrected for in the algorithmic assessment of multiple variables to improve the screening performance. Aspirin prophylaxis may still be viable in Asian women, but resource implication needs to be considered. Asian ethnicity should be taken into account before implementing pre-eclampsia screening strategies in the region. The variables included can be mixed and matched to achieve an optimal performance that is appropriate for economical restriction in individual countries.

The prediction of late-onset preeclampsia: Results from a longitudinal proteomics study

BACKGROUND

Late-onset preeclampsia is the most prevalent phenotype of this syndrome; nevertheless, only a few biomarkers for its early diagnosis have been reported. We sought to correct this deficiency using a high through-put proteomic platform.

METHODS

A case-control longitudinal study was conducted, including 90 patients with normal pregnancies and 76 patients with late-onset preeclampsia (diagnosed at ≥34 weeks of gestation). Maternal plasma samples were collected throughout gestation (normal pregnancy: 2-6 samples per patient, median of 2; late-onset preeclampsia: 2-6, median of 5). The abundance of 1,125 proteins was measured using an aptamers-based proteomics technique. Protein abundance in normal pregnancies was modeled using linear mixed-effects models to estimate mean abundance as a function of gestational age. Data was then expressed as multiples of-the-mean (MoM) values in normal pregnancies. Multi-marker prediction models were built using data from one of five gestational age intervals (8-16, 16.1-22, 22.1-28, 28.1-32, 32.1-36 weeks of gestation). The predictive performance of the best combination of proteins was compared to placental growth factor (PIGF) using bootstrap.

RESULTS

1) At 8-16 weeks of gestation, the best prediction model included only one protein, matrix metalloproteinase 7 (MMP-7), that had a sensitivity of 69% at a false positive rate (FPR) of 20% (AUC = 0.76); 2) at 16.1-22 weeks of gestation, MMP-7 was the single best predictor of late-onset preeclampsia with a sensitivity of 70% at a FPR of 20% (AUC = 0.82); 3) after 22 weeks of gestation, PlGF was the best predictor of late-onset preeclampsia, identifying 1/3 to 1/2 of the patients destined to develop this syndrome (FPR = 20%); 4) 36 proteins were associated with late-onset preeclampsia in at least one interval of gestation (after adjustment for covariates); 5) several biological processes, such as positive regulation of vascular endothelial growth factor receptor signaling pathway, were perturbed; and 6) from 22.1 weeks of gestation onward, the set of proteins most predictive of severe preeclampsia was different from the set most predictive of the mild form of this syndrome.

CONCLUSIONS

Elevated MMP-7 early in gestation (8-22 weeks) and low PlGF later in gestation (after 22 weeks) are the strongest predictors for the subsequent development of late-onset preeclampsia, suggesting that the optimal identification of patients at risk may involve a two-step diagnostic process.

Maternal and Cord Blood Plasma sEng and TGF-β1 in Patients with Hypertensive Disorders of Pregnancy: A Pilot Study in a South Indian Population

INTRODUCTION

Hypertensive Disorders of Pregnancy (HDP) are one of the most widespread complications of pregnancy that affects both mother and foetus. It has been observed that in Preeclampsia, the release of soluble angiogenic factors from the ischemic placenta into maternal plasma plays a crucial role in the pathogenesis.

AIM

To assess the plasma Soluble Endoglin (sEng) and Transforming Growth Factor (TGF-β1) levels in various types of HDP and to correlate the levels of these markers with the pregnancy outcome.

MATERIALS AND METHODS

A total of 128 pregnant women were recruited and the study was carried out for a period of three years. Cord blood and maternal blood plasma levels of sEng and TGF-β1 were analysed by ELISA kits in Control Pregnant Women (CPW), Gestational Hypertension (GH), Early Onset Preeclampsia (EOPE), Late Onset Preeclampsia (LOPE), and Eclampsia (E) during third trimester. The Gestational Age (GA) at the time of delivery and Birth Weight (BW) of the baby also were also evaluated.

RESULTS

The circulating levels of maternal and cord blood sEng were significantly higher in EOPE and E compared to CPW and GH. However, the maternal and cord blood levels of TGF-β1 were significantly lower in LOPE and E when compared to CPW and GH. The GA and BW of the baby were found to be significantly lower in EOPE and E compared to CPW, GH and LOPE. Also, a negative correlation was observed between sEng levels with pregnancy outcome; GA and BW. And also, a positive correlation was found between TGF-β1 and pregnancy outcome.

CONCLUSION

A generalised angiogenic imbalance and poor birth outcomes were observed in HDP. There is a spectrum of biochemical derangements related to angiogenesis in GH, EOPE, LOPE and E.

A computational analysis of in vivo VEGFR activation by multiple co-expressed ligands

The splice isoforms of vascular endothelial growth A (VEGF) each have different affinities for the extracellular matrix (ECM) and the coreceptor NRP1, which leads to distinct vascular phenotypes in model systems expressing only a single VEGF isoform. ECM-immobilized VEGF can bind to and activate VEGF receptor 2 (VEGFR2) directly, with a different pattern of site-specific phosphorylation than diffusible VEGF. To date, the way in which ECM binding alters the distribution of isoforms of VEGF and of the related placental growth factor (PlGF) in the body and resulting angiogenic signaling is not well-understood. Here, we extend our previous validated cell-level computational model of VEGFR2 ligation, intracellular trafficking, and site-specific phosphorylation, which captured differences in signaling by soluble and immobilized VEGF, to a multi-scale whole-body framework. This computational systems pharmacology model captures the ability of the ECM to regulate isoform-specific growth factor distribution distinctly for VEGF and PlGF, and to buffer free VEGF and PlGF levels in tissue. We show that binding of immobilized growth factor to VEGF receptors, both on endothelial cells and soluble VEGFR1, is likely important to signaling in vivo. Additionally, our model predicts that VEGF isoform-specific properties lead to distinct profiles of VEGFR1 and VEGFR2 binding and VEGFR2 site-specific phosphorylation in vivo, mediated by Neuropilin-1. These predicted signaling changes mirror those observed in murine systems expressing single VEGF isoforms. Simulations predict that, contrary to the 'ligand-shifting hypothesis,' VEGF and PlGF do not compete for receptor binding at physiological concentrations, though PlGF is predicted to slightly increase VEGFR2 phosphorylation when over-expressed by 10-fold. These results are critical to design of appropriate therapeutic strategies to control VEGF availability and signaling in regenerative medicine applications.

The use of angiogenic biomarkers in maternal blood to identify which SGA fetuses will require a preterm delivery and mothers who will develop pre-eclampsia

OBJECTIVE

To determine (1) whether maternal plasma concentrations of angiogenic and anti-angiogenic factors can predict which mothers diagnosed with "suspected small for gestational age fetuses (sSGA)" will develop pre-eclampsia (PE) or require an indicated early preterm delivery (≤ 34 weeks of gestation); and (2) whether risk assessment performance is improved using these proteins in addition to clinical factors and Doppler parameters.

METHODS

This prospective cohort study included women with singleton pregnancies diagnosed with sSGA (estimated fetal weight <10th percentile) between 24 and 34 weeks of gestation (n = 314). Plasma concentrations of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1), soluble endoglin (sEng) and placental growth factor (PlGF) were determined in maternal blood obtained at the time of diagnosis. Doppler velocimetry of the umbilical (Umb) and uterine (UT) arteries was performed. The outcomes were (1) subsequent development of PE; and (2) indicated preterm delivery at ≤ 34 weeks of gestation (excluding deliveries as a result of spontaneous preterm labor, preterm pre-labor rupture of membranes or chorioamnionitis).

RESULTS

(1) The prevalence of PE and indicated preterm delivery was 9.2% (n = 29/314) and 7.3% (n = 23/314), respectively; (2) the area under the receiver operating characteristic curve (AUC) for the identification of patients who developed PE and/or required indicated preterm delivery was greater than 80% for the UT artery pulsatility index (PI) z-score and each biochemical marker (including their ratios) except sVEGFR-1 MoM; (3) using cutoffs at a false positive rate of 15%, women with abnormal plasma concentrations of angiogenic/anti-angiogenic factors were 7-13 times more likely to develop PE, and 12-22 times more likely to require preterm delivery than those with normal plasma MoM concentrations of these factors; (4) sEng, PlGF, PIGF/sEng and PIGF/sVEGFR-1 ratios MoM, each contributed significant information about the risk of PE beyond that provided by clinical factors and/or Doppler parameters: women who had low MoM values for these biomarkers were at 5-9 times greater risk of developing PE than women who had normal values, adjusting for clinical factors and Doppler parameters (adjusted odds ratio for PlGF: 9.1, PlGF/sEng: 5.6); (5) the concentrations of sVEGFR-1 and PlGF/sVEGFR-1 ratio MoM, each contributed significant information about the risk of indicated preterm delivery beyond that provided by clinical factors and/or Doppler parameters: women who had abnormal values were at 8-9 times greater risk for indicated preterm delivery, adjusting for clinical factors and Doppler parameters; and (6) for a two-stage risk assessment (Umb artery Doppler followed by Ut artery Doppler plus biochemical markers), among women who had normal Umb artery Doppler velocimetry (n = 279), 21 (7.5%) developed PE and 11 (52%) of these women were identified by an abnormal UT artery Doppler mean PI z-score (>2SD): a combination of PlGF/sEng ratio MoM concentration and abnormal UT artery Doppler velocimetry increased the sensitivity of abnormal UT artery Doppler velocimetry to 76% (16/21) at a fixed false-positive rate of 10% (p = 0.06).

CONCLUSION

Angiogenic and anti-angiogenic factors measured in maternal blood between 24 and 34 weeks of gestation can identify the majority of mothers diagnosed with "suspected SGA" who subsequently developed PE or those who later required preterm delivery ≤ 34 weeks of gestation. Moreover, incorporation of these biochemical markers significantly improves risk assessment performance for these outcomes beyond that of clinical factors and uterine and umbilical artery Doppler velocimetry.

Maternal plasma angiogenic index-1 (placental growth factor/soluble vascular endothelial growth factor receptor-1) is a biomarker for the burden of placental lesions consistent with uteroplacental underperfusion: a longitudinal case-cohort study

BACKGROUND

Placental lesions consistent with maternal vascular underperfusion (MVU) are thought to be pathogenically linked to preeclampsia, small-for-gestational-age newborns, fetal death, and spontaneous preterm labor and delivery; yet, these lesions cannot be diagnosed antenatally. We previously reported that patients with such conditions and lesions have an abnormal profile of the angiogenic placental growth factor (PlGF) and antiangiogenic factors (eg, soluble vascular endothelial growth factor receptor [sVEGFR]-1).

OBJECTIVE

The objectives of this study were to: (1) examine the relationship between the maternal plasma PlGF/sVEGFR-1 concentration ratio (referred to herein as angiogenic index-1) and the burden of histologic placental features consistent with MVU; and (2) test the hypothesis that angiogenic index-1 can identify patients in the midtrimester who are destined to deliver before 34 weeks of gestation with multiple (ie, ≥3) histologic placental features consistent with MVU.

STUDY DESIGN

A 2-stage case-cohort sampling strategy was used to select participants from among 4006 women with singleton gestations enrolled from 2006 through 2010 in a longitudinal study. Maternal plasma angiogenic index-1 ratios were determined using enzyme-linked immunosorbent assays. Placentas underwent histologic examination according to standardized protocols by experienced pediatric pathologists who were blinded to clinical diagnoses and pregnancy outcomes. The diagnosis of lesions consistent with MVU was made using criteria proposed by the Perinatal Section of the Society for Pediatric Pathology. Weighted analyses were performed to reflect the parent cohort; "n*" is used to reflect weighted frequencies.

RESULTS

(1) Angiogenic index-1 (PlGF/sVEGFR-1) concentration ratios were determined in 7560 plasma samples collected from 1499 study participants; (2) the prevalence of lesions consistent with MVU was 21% (n* = 833.9/3904) and 27% (n* = 11.4/42.7) of women with ≥3 MVU lesions delivered before 34 weeks of gestation; (3) a low angiogenic index-1 (<2.5th quantile for gestational age) in maternal plasma samples obtained within 48 hours of delivery had a sensitivity of 73% (n* = 8.3/11.4; 95% confidence interval [CI], 47-98%), a specificity of 94% (n* = 3130.9/3316.2; 95% CI, 94-95%), a positive likelihood ratio of 12.2, and a negative likelihood ratio of 0.29 in the identification of patients who delivered placentas with ≥3 MVU lesions at <34 weeks; (4) prospectively, at 20-23 weeks of gestation, a maternal plasma concentration of angiogenic index-1 <2.5th quantile identified 70% (n* = 7.2/10.3; 95% CI, 42-98%) of patients who delivered placentas with ≥3 MVU lesions before 34 weeks (specificity, 97% [n* = 2831.3/2918; 95% CI, 96-98%]; positive likelihood ratio, 23; negative likelihood ratio, 0.31); and (5) among women without obstetrical complications who delivered at term, angiogenic index-1 was lower in women with than without placental lesions consistent with MVU (P < .05).

CONCLUSION

Maternal plasma angiogenic index-1 (PlGF/sVEGFR-1) is the first biomarker for the burden of placental lesions consistent with MVU. We propose that an accumulation of these lesions in placentas delivered before 34 weeks is a histologic counterpart of an antiangiogenic profile.

Elevated levels of neuropeptide Y in preeclampsia: A pilot study implicating a role for stress in pathogenesis of the disease

OBJECTIVE

To determine if preeclampsia (PE) is associated with dysregulation of the neuropeptide Y (NPY) system.

METHODS

The study enrolled 114 subjects either with normal pregnancy (NP) or with PE. Systolic blood pressure (SBP) was collected from patients using a standard sphygmomanometer. The PE patients were divided into two groups based on the gestational age (GA) at delivery - placental PE (PLPE, GA <34 weeks) or maternal PE (MTPE, GA ≥34 weeks). NPY was measured in platelet rich plasma (PRP), platelet poor plasma (PPP) and in the serum of NP and PE patients utilizing radioimmunoassay. Serum levels of soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) were measured in NP and PE subjects by ELISA.

RESULTS

SBP was higher in PE compared to NP. Circulating NPY in serum and PRP, as well as NPY content per 100,000 platelets, but not its concentrations in PPP, were elevated in PE, as compared to NP. The highest NPY concentrations were observed in sera and PRP of patients with MTPE. PE patients had also elevated levels of sFlt-1, as compared to NP, although no difference between PLPE and MTPL groups were observed. There was no increase in P1GF in PE patients.

CONCLUSION

Systemic NPY is elevated in PE patients, as compared to NP. This increase is observed in blood fractions containing platelets, suggesting accumulation of the peptide in these cells. NPY concentrations are particularly high in patients with MTPE, underlying differences in etiology between PLPE and MTPE. Our study implicates NPY as a potential target in antihypertensive therapies for PE patients.

Preeclampsia and Vascular Function: A Window to Future Cardiovascular Disease Risk

Preeclampsia affects ∼3%-7% of all pregnancies and is the third leading cause of maternal mortality globally. Growing evidence indicates that preeclampsia results from vascular dysfunction, which also increases the risk for future cardiovascular events. Until recently, preeclampsia was considered a disorder limited to pregnancy, which fully resolved with the delivery of the placenta; however, it is now clear that women with a history of preeclampsia have approximately double the risk of future cardiovascular events compared to women with normotensive pregnancies. The aims of this review were to describe the hemodynamic and vascular changes that occur in normal and preeclamptic pregnancies, to review noninvasive methods to test vascular function, and to discuss the associated increased cardiovascular disease risk related to preeclampsia.

Serum VEGF and PGF may be significant markers in prediction of severity of preeclampsia

OBJECTIVE

The aim of this study evaluate the value of vascular endothelial growth factor (VEGF) and placental growth factor (PGF) serum levels in prediction of preeclampsia, severity and onset time of the disease.

METHODS

Twenty five placentas of pregnant women diagnosed with preeclampsia (15 severe preeclampsia, 10 mild preeclampsia) and peripheral venous blood samples were collected. The placental and serum levels of VEGF and PGF were measured.

RESULTS

VEGF level was significantly higher in cases and the optimal cut-off point was calculated as 600.5 to differentiate the cases and the controls, with 64% sensitivity and 100% specificity. There was a significant increase in median serum level of VEGF in severe cases compared to the mild cases and the controls. The optimal cut-off point for VEGF was calculated as 673.5 to differentiate mild and severe cases, with 93.3% sensitivity and 90% specificity. Whereas, PGF was significantly lower in severe cases than that in the mild cases and controls. The optimal cut-off point for PGF was calculated as 16.1 to differentiate mild and severe cases, with 66.7% sensitivity and 100% specificity.

CONCLUSION

VEGF and PGF may be significant markers in prediction of severity of preeclampsia, and VEGF may also be valuable in prediction of preeclampsia.

Full-length human placental sFlt-1-e15a isoform induces distinct maternal phenotypes of preeclampsia in mice

OBJECTIVE

Most anti-angiogenic preeclampsia models in rodents utilized the overexpression of a truncated soluble fms-like tyrosine kinase-1 (sFlt-1) not expressed in any species. Other limitations of mouse preeclampsia models included stressful blood pressure measurements and the lack of postpartum monitoring. We aimed to 1) develop a mouse model of preeclampsia by administering the most abundant human placental sFlt-1 isoform (hsFlt-1-e15a) in preeclampsia; 2) determine blood pressures in non-stressed conditions; and 3) develop a survival surgery that enables the collection of fetuses and placentas and postpartum (PP) monitoring.

METHODS

Pregnancy status of CD-1 mice was evaluated with high-frequency ultrasound on gestational days (GD) 6 and 7. Telemetry catheters were implanted in the carotid artery on GD7, and their positions were verified by ultrasound on GD13. Mice were injected through tail-vein with adenoviruses expressing hsFlt-1-e15a (n = 11) or green fluorescent protein (GFP; n = 9) on GD8/GD11. Placentas and pups were delivered by cesarean section on GD18 allowing PP monitoring. Urine samples were collected with cystocentesis on GD6/GD7, GD13, GD18, and PPD8, and albumin/creatinine ratios were determined. GFP and hsFlt-1-e15a expression profiles were determined by qRT-PCR. Aortic ring assays were performed to assess the effect of hsFlt-1-e15a on endothelia.

RESULTS

Ultrasound predicted pregnancy on GD7 in 97% of cases. Cesarean section survival rate was 100%. Mean arterial blood pressure was higher in hsFlt-1-e15a-treated than in GFP-treated mice (∆MAP = 13.2 mmHg, p = 0.00107; GD18). Focal glomerular changes were found in hsFlt-1-e15a -treated mice, which had higher urine albumin/creatinine ratios than controls (109.3 ± 51.7 μg/mg vs. 19.3 ± 5.6 μg/mg, p = 4.4 x 10(-2); GD18). Aortic ring assays showed a 46% lesser microvessel outgrowth in hsFlt-1-e15a-treated than in GFP-treated mice (p = 1.2 x 10(-2)). Placental and fetal weights did not differ between the groups. One mouse with liver disease developed early-onset preeclampsia-like symptoms with intrauterine growth restriction (IUGR).

CONCLUSIONS

A mouse model of late-onset preeclampsia was developed with the overexpression of hsFlt-1-e15a, verifying the in vivo pathologic effects of this primate-specific, predominant placental sFlt-1 isoform. HsFlt-1-e15a induced early-onset preeclampsia-like symptoms associated with IUGR in a mouse with a liver disease. Our findings support that hsFlt-1-e15a is central to the terminal pathway of preeclampsia, and it can induce the full spectrum of symptoms in this obstetrical syndrome.

Growth factor purification and delivery systems (PADS) for therapeutic angiogenesis

Background

Therapeutic angiogenesis with vascular endothelial growth factor (VEGF), delivered either via recombinant protein infusion or via gene therapy, has shown promise in preclinical models of various diseases including myocardial infarction, renovascular disease, preeclampsia, and neurodegenerative disorders. However, dosing, duration of expression, and tissue specificity are challenges to VEGF gene therapy, and recombinant VEGF delivery suffers from extremely rapid plasma clearance, necessitating continuous infusion and/or direct injection at the site of interest.

Methods

Here we describe a novel growth factor purification and delivery system (PADS) generated by fusion of VEGF₁₂₁ to a protein polymer based on Elastin-like Polypeptide (ELP). ELP is a thermally responsive biopolymer derived from a five amino acid repeat sequence found in human tropoelastin. _VEGFPADS were constructed by fusion of the ELP coding sequence in-frame with the VEGF₁₂₁ coding sequence connected by a flexible di-glycine linker. In vitro activity of _VEGFPADS was determined using cell proliferation, tube formation, and migration assays with vascular endothelial cells. Pharmacokinetics and biodistribution of _VEGFPADS in vivo were compared to free VEGF in mice using quantitative fluorescence techniques.

Results

ELP fusion allowed for recombinant expression and simple, non-chromatographic purification of the ELP-VEGF₁₂₁ chimera in yields as high as 90 mg/L of culture and at very high purity. ELP fusion had no effect on the VEGF activity, as the _VEGFPADS were equally potent as free VEGF₁₂₁ in stimulating HUVEC proliferation, tube formation, and migration. Additionally, the _VEGFPADS had a molecular weight five-fold larger than free VEGF₁₂₁, which lead to slower plasma clearance and an altered biodistribution after systemic delivery in vivo.

Conclusion

PADS represent a new method of both purification and in vivo stabilization of recombinant growth factors. The use of this system could permit recombinant growth factors to become viable options for therapeutic angiogenesis in a number of disease models.

Electronic supplementary material

The online version of this article (doi:10.1186/s13221-014-0026-3) contains supplementary material, which is available to authorized users.

In vivo experiments reveal the good, the bad and the ugly faces of sFlt-1 in pregnancy

Objective

Soluble fms-like tyrosine kinase (sFlt)-1-e15a, a primate-specific sFlt-1-isoform most abundant in the human placenta in preeclampsia, can induce preeclampsia in mice. This study compared the effects of full-length human (h)sFlt-1-e15a with those of truncated mouse (m)sFlt-1(1-3) used in previous preeclampsia studies on pregnancy outcome and clinical symptoms in preeclampsia.

Methods

Mice were injected with adenoviruses or fiber-mutant adenoviruses overexpressing hsFlt-1-e15a, msFlt-1(1-3) or control GFP under the CMV or CYP19A1 promoters on gestational day 8 (GD8) and GD11. Placentas and pups were delivered by cesarean section, and dams were monitored postpartum. Blood pressure was telemetrically recorded. Urine samples were collected with cystocentesis and examined for albumin/creatinine ratios. Tissue specimens were evaluated for transgene as well as endogenous mFlt-1 and msFlt-1-i13 expression. H&E-, Jones- and PAS-stained kidney sections were histopathologically examined. Placental GFP expression and aortic ring assays were investigated with confocal microscopy.

Results

Mean arterial blood pressure (MAP) was elevated before delivery in hsFlt-1-e15a-treated mice compared to controls (GD18: ΔMAP = 7.8 mmHg, p = 0.009), while ΔMAP was 12.8 mmHg (GD18, p = 0.005) in msFlt-1(1-3)-treated mice. Urine albumin/creatinine ratio was higher in hsFlt-1-e15a-treated mice than in controls (GD18, p = 0.04; PPD8, p = 0.03), and msFlt-1(1-3)-treated mice had marked proteinuria postpartum (PPD8, p = 4×10⁻⁵). Focal glomerular changes were detected in hsFlt-1-e15a and msFlt-1(1-3)-treated mice. Aortic ring microvessel outgrowth was decreased in hsFlt-1-e15a (p = 0.007) and msFlt-1(1-3)-treated (p = 0.02) mice. Full-length msFlt-1-i13 expression was unique for the placenta. In hsFlt-1-e15a-treated mice, the number of pups (p = 0.046), total weight of living pups (p = 0.04) and maternal weights (p = 0.04) were higher than in controls. These differences were not observed in truncated msFlt-1(1-3)-treated mice.

Conclusions

Truncated msFlt-1(1-3) simulated the preeclampsia-promoting effects of full-length hsFlt-1. MsFlt-1(1-3) had strong effect on maternal endothelium but not on placentas and embryos. In contrast, hsFlt-1-e15a induced preeclampsia-like symptoms; however, it also increased litter size. In accord with the predominant placental expression of hsFlt-1-e15a and msFlt-1-i13, full-length sFlt-1 may have a role in the regulation of embryonic development. These observations point to the difference in the biological effects of full-length and truncated sFlt-1 and the changes in the effect of full-length sFlt-1 during pregnancy, and may have important implications in the management of preeclampsia.

Placental Nkx2-5 and target gene expression in early-onset and severe preeclampsia

OBJECTIVE

Preeclampsia (PE) affects 2-8% of pregnancies worldwide and is a significant source of maternal and neonatal morbidity and mortality. However, the mechanisms underlying PE are poorly understood and major questions regarding etiology and risk factors remain to be addressed. Our objective was to examine whether abnormal expression of the cardiovascular developmental transcription factor, Nkx2-5, was associated with early onset and severe preeclampsia (EOSPE).

METHODS

Using qPCR and immunohistochemical assay, we examined expression of Nkx2-5 and target gene expression in EOSPE and control placental tissue. We tested resulting mechanistic hypotheses in cultured cells using shRNA knockdown, qPCR, and western blot.

RESULTS

Nkx2-5 is highly expressed in racially disparate fashion (Caucasians > African Americans) in a subset of early EOSPE placentae. Nkx2-5 mRNA expression is highly correlated (Caucasians > African Americans) to mRNA expression of the preeclampsia marker sFlt-1, and of the Nkx2-5 target and RNA splicing factor, Sam68. Knockdown of Sam68 expression in cultured cells significantly impacts sFlt-1 mRNA isoform generation in vitro, supporting a mechanistic hypothesis that Nkx2-5 impacts EOSPE severity in a subset of patients via upregulation of Sam68 to increase sFlt-1 expression. Expression of additional Nkx2-5 targets potentially regulating metabolic stress response is also elevated in a racially disparate fashion in EOSPE.

CONCLUSIONS

Expression of Nkx2-5 and its target genes may directly influence the genesis and racially disparate severity, and define a mechanistically distinct subclass of EOSPE.

Decreased placental miR-126 expression and vascular endothelial growth factor levels in patients with pre-eclampsia

OBJECTIVES

To detect microRNA (miR)-126 expression and its correlation with vascular endothelial growth factor (VEGF) levels in placentas from patients with pre-eclampsia compared with those from normotensive pregnancies.

METHODS

miR-126 expression, and VEGF mRNA and protein levels, in placentas collected sequentially from patients with pre-eclampsia and normotensive pregnancies were measured using real-time reverse transcription-polymerase chain reaction and Western blot, respectively. The relationship between miR-126 and VEGF expression was analysed statistically. The regulatory effect of miR-126 on VEGF expression in human placental choriocarcinoma (BeWo) cells in vitro was also investigated.

RESULTS

miR-126 expression was decreased, and VEGF mRNA and protein levels were significantly lower, in placentas from patients with pre-eclampsia (n = 115) compared with placentas from normotensive pregnancies (n = 115). A positive correlation was found between VEGF mRNA and miR-126 expression (r = 0.79). In addition, miR-126 overexpression significantly upregulated VEGF expression in BeWo cells, whereas miR-126 downregulation decreased VEGF expression.

CONCLUSIONS

miR-126 was downregulated in placentas from patients with pre-eclampsia and this correlated with decreased VEGF expression. These findings indicate that miRNA-126 may be involved in pre-eclampsia pathogenesis and could be a potential biomarker for this disease.

Placenta growth factor induces invasion and activates p70 during rapamycin treatment in trophoblast cells

PROBLEM

Aberrant trophoblast invasion has been associated with human intrauterine growth restriction (IUGR) and preeclampsia (PE). Our objective was to determine placenta growth factor (PlGF)-mediated regulation of cell invasion in trophoblast cells with reduced mammalian target of Rapamycin (mTOR) signaling.

METHOD OF STUDY

First trimester SW 71 trophoblast cells were subjected to invasion assays with the following conditions: 10% FBS, 10% FBS with Rapamycin, and 10% FBS with Rapamycin and PlGF. mTOR siRNA was also done in these cells. Western blots were performed on cell lysates with antibodies against phospho- and total mTOR, 70-kDa ribosomal protein kinase I (p70), 4EBP1, extracellular regulated kinase (ERK), and phosphatidylinositol-3 kinase (AKT).

RESULTS

Compared to controls, trophoblast cells showed: (i) a 33% decrease in invasion following Rapamycin treatment, (ii) protection from decreased invasion following Rapamycin and PlGF treatment, (iii) a 31% decrease in mTOR phosphorylation with Rapamycin, (iv) increased phosphorylation of p70 (43%) with Rapamycin and PlGF, and (v) a 76% decrease in invasion following mTOR depletion.

CONCLUSION

We conclude that first trimester trophoblast invasion is functionally decreased when phosphorylation of mTOR is prevented and this decrease is recovered with the addition of PlGF. Mechanistically, this recovery involves the phosphorylation of p70 independent of mTOR.

Soluble endoglin, transforming growth factor-Beta 1 and soluble tumor necrosis factor alpha receptors in different clinical manifestations of preeclampsia

Background

Despite intensive research, the etiopathogenesis of preeclampsia (PE) remains uncertain. Inflammatory and angiogenic factors are thought to play considerable roles in this disease. The objective of this study was to investigate the association between soluble endoglin (sEng), transforming growth factor beta-1 (TGF-β1) and tumor necrosis factor alpha soluble receptors (sTNF-Rs) and the clinical manifestations of PE.

Methods

Plasma levels of sEng, TGF-β1 and sTNF-Rs were determined by ELISA in 23 non-pregnant, 21 normotensive pregnant and 43 PE women. PE women were stratified into subgroups according to the severity [mild (n = 12) and severe (n = 31)] and onset-time of the disease [early (n = 19) and late (n = 24)].

Results

Pregnancy was associated with higher levels of sEng, sTNF-R1 and sTNF-R2 than the non-pregnant state. Moreover, PE women had higher levels of sEng and sTNF-R1 than normotensive pregnant women. No difference was found in TGF-β1 levels, comparing the three study groups. Late PE had higher levels of sTNF-R1 and sTNF-R2 than early PE. No significant differences were found in sEng and TGF-β1 comparing early and late PE. sEng levels were higher in severe PE than in mild PE and no difference was found for TGF-β1, sTNF-R1 and sTNF-R2 levels. There was a positive correlation among sEng, TNF-R1 and sTNF-2 levels. Logistic regression analysis revealed that primiparity and sEng levels are independently associated with the development of PE. Furthermore, sEng levels are independently associated with the disease severity.

Conclusions

These results suggest that pregnancy is a condition associated with higher levels of anti-angiogenic and pro-inflammatory factors than the non-pregnant state and that PE is associated with an imbalance of these factors in the maternal circulation.

Vascular endothelial growth factor +936C/T, -634G/C, -2578C/A, and -1154G/A polymorphisms with risk of preeclampsia: a meta-analysis

BACKGROUND

Emerging evidence showed that VEGF gene polymorphisms are involved in the regulation of VEGF protein expression, thus increasing an individual's susceptibility to preeclampsia (PE); but individually published results are inconclusive. The aim of this meta-analysis was to investigate the associations between VEGF gene polymorphisms and PE risk.

METHODS

A systematic literature search of MEDLINE, Embase, Web of Science, and CNKI (Chinese National Knowledge Infrastructure) databases was conducted. Statistical analyses were performed using STATA 12.0 software and Review manager 5.1. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

RESULTS

According to the inclusion criteria, 11 case-control studies were finally included in this meta-analysis. A total of 1,069 PE cases and 1,315 controls were included in this study. Our meta-analysis indicated that VEGF +936C/T (T vs. C, OR = 1.52, 95%CI = 1.08-2.12) or -634G/C polymorphism (C vs. G, OR = 1.24, 95% CI = 1.03-1.50) was associated with the risk of PE, whereas there was no association between -2578C/A (A vs. C, OR = 0.98, 95%CI = 0.82-1.16) or -1154G/A (A vs. G, OR = 1.30, 95%CI = 0.94-1.78) polymorphism and PE risk in our study.

CONCLUSION

Our meta-analysis suggested that VEGF -2578C/A or -1154G/A polymorphism had no association with PE risk in all examined patients, whereas there was an association between VEGF +936C/T or -634G/C polymorphism and risk of PE.

Maternal plasma soluble TRAIL is decreased in preeclampsia

OBJECTIVE

Preeclampsia (PE) is characterized by systemic intravascular inflammation. Women who develop PE are at an increased risk for cardiovascular disease in later life. Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) has anti-atherosclerotic effects in endothelial cells and can mediate neutrophil apoptosis. Low soluble TRAIL (sTRAIL) and high C-reactive protein (CRP) concentrations are associated with an increased risk of future cardiovascular disease in non-pregnant individuals. The aim of this study was to determine whether maternal plasma concentrations of sTRAIL and CRP differ between women with PE and those with uncomplicated pregnancies.

METHOD

This cross-sectional study included women with an uncomplicated pregnancy (n = 93) and those with PE (n = 52). Maternal plasma concentrations of sTRAIL and CRP concentrations were determined by ELISA.

RESULTS

1) The median plasma sTRAIL concentration (pg/mL) was significantly lower and the median plasma CRP concentration was significantly higher in women with PE than in those with an uncomplicated pregnancy (25.55 versus 29.17; p = 0.03 and 8.0 versus 4.1; p = 0.001, respectively); 2) the median plasma concentration sTRAIL/CRP ratio was two-fold lower in women with PE than in those with an uncomplicated pregnancy (p < 0.001); and 3) women with plasma sTRAIL and CRP ratio in the lowest quartile were 8 times more likely to have PE than women with concentrations in the upper three quartiles (OR 8.9; 95% CI: 2.8-27.8).

CONCLUSION

Maternal plasma sTRAIL concentrations are lower (while those of CRP are higher) in women with PE than in those with uncomplicated pregnancies. These findings are consistent with the evidence of intravascular inflammation in this disorder.

Comparison of placental growth factor and fetal flow Doppler ultrasonography to identify fetal adverse outcomes in women with hypertensive disorders of pregnancy: an observational study

BACKGROUND

Hypertensive disorders of pregnancy and intrauterine growth restriction (IUGR) are leading causes of maternal and perinatal morbidity and mortality. Failure to detect intrauterine growth restriction in women at high risk has been highlighted as a significant avoidable cause of serious fetal outcome. In this observational study we compare fetal flow using Doppler ultrasonography with a new test for placental growth factor (PlGF) to predict fetal adverse events.

METHODS

Eighty-nine women with hypertensive disorders of pregnancy (24 with chronic hypertension, 17 with gestational hypertension, 12 with HELLP syndrome, 19 with preeclampsia and 17 with superimposed preeclampsia) were enrolled. A single maternal blood sample to measure free PlGF (Alere Triage) taken before 35 weeks of pregnancy was compared to the last Doppler ultrasound measurement of fetal flow before delivery. PlGF was classified as normal (PlGF≥100 pg/ml), low (12<PlGF<100) or very low (PlGF≤12 pg/ml). A positive test for abnormal fetal flow was defined as either signs of centralisation of the fetal circulation or diastolic block or reverse flow in the umbilical artery or descending aorta; this was a criterion for delivery. Fetal outcomes were intrauterine growth restriction and birth before 37 weeks of pregnancy.

RESULTS

In total 61/89 women had a preterm birth and 22 infants had IUGR. Of those who delivered preterm, 20/20 women with abnormal fetal flow and 36/41 (87.8%) women with normal fetal flow had low or very low PlGF. Of those infants with IUGR, 22/22 had low or very low maternal PlGF and 10/22 had abnormal fetal flow.

CONCLUSIONS

PlGF may provide useful information before 35th gestational week to identify fetuses requiring urgent delivery, and those at risk of later adverse outcomes not identified by fetal flow Doppler ultrasonography.

Maternal plasma concentrations of sST2 and angiogenic/anti-angiogenic factors in preeclampsia

OBJECTIVES

Angiogenic/anti-angiogenic factors have emerged as one of the promising biomarkers for the prediction of preeclampsia. Since not all patients with preeclampsia can be identified by these analytes, the search for additional biomarkers continues. The soluble form of ST2 (sST2), a protein capable of binding to interleukin (IL)-33 and thus contributing to a Th1-biased immune response, has been reported to be elevated in maternal plasma of women with preeclampsia. The aims of this study were to examine: (1) differences in maternal plasma concentrations of sST2 and IL-33 between women diagnosed with preeclampsia and those having uncomplicated pregnancies; (2) the relationship between sST2, umbilical and uterine artery Doppler velocimetry, and the severity of preeclampsia; and (3) the performance of sST2 and angiogenic/anti-angiogenic factors in identifying patients with preeclampsia at the time of diagnosis.

METHODS

This cross-sectional study included women with preeclampsia (n = 106) and women with an uncomplicated pregnancy (n = 131). Plasma concentrations of sST2, IL-33, soluble vascular endothelial growth factor receptor (sVEGFR)-1, soluble endoglin (sEng) and placental growth factor (PlGF) were determined by enzyme linked immune sorbent assay. Area under the receiver operating characteristic curve (AUC) for the identification of preeclampsia was examined for each analyte.

RESULTS

(1) Patients with preeclampsia had a higher mean plasma concentrations of sST2 than those with an uncomplicated pregnancy (p < 0.0001), while no significant difference in the mean plasma concentration of IL-33 between the two groups was observed; (2) the magnitude of this difference was greater in early-onset, compared to late-onset disease, and in severe compared to mild preeclampsia; (3) sST2 plasma concentrations did not correlate with the results of uterine or umbilical artery Doppler velocimetry (p = 0.7 and p = 1, respectively) among women with preeclampsia; (4) sST2 correlated positively with plasma concentrations of sVEGFR1-1 and sEng (Spearman's Rho = 0.72 and 0.63; each p < 0.0001), and negatively with PlGF (Spearman's Rho = -0.56, p < 0.0001); and (5) while the AUC achieved by sST2 and angiogenic/anti-angiogenic factors in identifying women with preeclampsia at the time of diagnosis were non-significantly different prior to term (<37 weeks of gestation), thereafter the AUC achieved by sST2 was significantly less than that achieved by angiogenic/anti-angiogenic factors.

CONCLUSIONS

Preeclampsia is associated with increased maternal plasma concentrations of sST2. The findings that sST2 concentrations do not correlate with uterine or umbilical artery Doppler velocimetry in women with preeclampsia suggest that elevated maternal plasma sST2 concentrations in preeclampsia are not related to the increased impedance to flow in the utero-placental circulation. The performance of sST2 in identifying preeclampsia at the time of diagnosis prior to 37 weeks of gestation was comparable to that of angiogenic/anti-angiogenic factors. It remains to be elucidated if an elevation of maternal plasma sST2 concentrations in pregnancy is specific to preeclampsia.

Maternal plasma concentrations of angiogenic/antiangiogenic factors in the third trimester of pregnancy to identify the patient at risk for stillbirth at or near term and severe late preeclampsia

OBJECTIVE

To determine whether maternal plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), and soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) at 30-34 weeks of gestation can identify patients at risk for stillbirth, late preeclampsia, and delivery of small-for-gestational-age (SGA) neonates.

STUDY DESIGN

A prospective cohort study included 1269 singleton pregnant women from whom blood samples were obtained at 30-34 weeks of gestation and who delivered at >34 weeks of gestation. Plasma concentrations of PlGF, sEng, and sVEGFR-1 were determined by enzyme-linked immunosorbent assay.

RESULTS

The prevalence of late (>34 weeks of gestation) preeclampsia, severe late preeclampsia, stillbirth, and SGA was 3.2% (n = 40), 1.8% (n = 23), 0.4% (n = 5), and 8.5% (n = 108), respectively. A plasma concentration of PlGF/sEng <0.3 MoM was associated with severe late preeclampsia (adjusted odds ratio, 16); the addition of PlGF/sEng to clinical risk factors increased the area under the receiver-operating characteristic curve from 0.76 to 0.88 (P = .03). The ratio of PlGF/sEng or PlGF/sVEGFR-1 in the third trimester outperformed those obtained in the first or second trimester and uterine artery Doppler velocimetry at 20-25 weeks of gestation for the prediction of severe late preeclampsia (comparison of areas under the receiver-operating characteristic curve; each P ≤ .02). Both PlGF/sEng and PlGF/sVEGFR-1 ratios achieved a sensitivity of 74% with a fixed false-positive rate of 15% for the identification of severe late preeclampsia. A plasma concentration of PlGF/sVEGFR-1 <0.12 MoM at 30-34 weeks of gestation had a sensitivity of 80%, a specificity of 94%, and a likelihood ratio of a positive test of 14 for the identification of subsequent stillbirth. Similar findings (sensitivity 80%; specificity 93%) were observed in a separate case-control study.

CONCLUSION

Risk assessment for stillbirth and severe late preeclampsia in the third trimester is possible with the determination of maternal plasma concentrations of angiogenic and antiangiogenic factors at 30-34 weeks of gestation.

Evidence of an imbalance of angiogenic/antiangiogenic factors in massive perivillous fibrin deposition (maternal floor infarction): a placental lesion associated with recurrent miscarriage and fetal death

OBJECTIVE

Massive perivillous fibrin deposition (MPFD) is associated with serious complications of pregnancy including recurrent spontaneous abortion, fetal growth restriction, and fetal demise. The aim of this study was to determine whether maternal plasma concentrations of angiogenic/antiangiogenic factors in MPFD differ from those of uncomplicated pregnancies.

STUDY DESIGN

This retrospective longitudinal case-control study included MPFD cases (n = 10) and control patients (n = 175) with uncomplicated pregnancies who were enrolled in a longitudinal study and delivered at term. Serial plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), and soluble vascular endothelial growth factor receptor (sVEGFR)-1 and -2 were determined by an enzyme-linked immunosorbent assay (cases, n = 28 samples; controls, n = 723 samples). Individual analyte concentrations were averaged across gestational age at specimen collection intervals. Linear mixed models were used to test for differences in log-transformed mean analyte concentrations both overall and as a function of time.

RESULTS

The following results were found: (1) patients with MPFD had a lower mean plasma PlGF concentration (P = .03) and higher mean plasma concentrations of sVEGFR-1 and sEng (both P < .01) than controls, adjusted for potential confounders; (2) the mean plasma concentration of PlGF differed further among cases and controls as a function of gestational age interval (P < .0001); however, mean sVEGFR-1 and sEng group differences as a function of gestational age interval approached but did not reach significance (P = .09 and P = .11, respectively); (3) patients with MPFD had lower mean plasma concentrations of PlGF/sVEGFR-1 (P < .0001) and PlGF/sEng (P < .001): both of these relationships differed further as a function of gestational age interval (both P < .0001); and (4) differences in mean sVEGFR-1, sEng, and the ratios of PlGF to sVEGFR-1 and PlGF to sEng were observed before 20 weeks of gestation.

CONCLUSION

An imbalance of angiogenic/antiangiogenic factors is present in patients with MPFD prior to the diagnosis. We propose that these changes participate in the mechanisms responsible for adverse pregnancy outcomes in patients with MPFD.

Evaluation of a rapid and simple placental growth factor test in hypertensive disorders of pregnancy

The aim of this study was to investigate the diagnostic accuracy of the Triage placental growth factor (PlGF) assay, together with its prognostic efficiency in determining the need for preterm delivery in all forms of hypertensive disorders of pregnancy. A total of 130 pregnant women with a diagnosis of preeclampsia (PE: 23), HELLP syndrome (20), superimposed preeclampsia (SIPE: 17), chronic hypertension (CHT: 25), gestational hypertension (GHT: 18) and 27 normotensive pregnant controls were enrolled in this case-control study. A single blood sample was taken between 22 and 34 weeks of gestation, and the plasma was analyzed for PlGF using the Alere Triage PlGF assay. The PlGF levels found in all hypertensive disorder groups differed significantly from those observed in controls. There was a highly significant difference in PlGF concentrations between women with a pregnancy duration <35 weeks and controls. Using a gestational age-dependent threshold of 5% of normal, a positive PlGF test predicted delivery before 35 weeks in 93.7% of hypertensive women and delivery before 37 weeks in 90.5% of hypertensive women. A positive PlGF test identified the following proportions of hypertensive patients: 95.7% (PE), 95.0% (HELLP syndrome), 82.4% (SIPE), 60.0% (CHT) and 44.4% (GHT). A positive PlGF test was associated with a significantly shorter duration of pregnancy (hazard ratio of 3.43 adjusted for the gestational age at the time of sample collection and hypertension with proteinuria). In conclusion, PlGF concentrations are significantly lower in all hypertensive disorders. A positive test using the Triage PlGF assay at 22-34 weeks of gestation predicts delivery before 37 weeks in women with both proteinuric and non-proteinuric hypertensive disorders of pregnancy.

Magnesium sulfate therapy of preeclampsia: an old tool with new mechanism of action and prospect in management and prophylaxis

A disturbed balance between angiogenic and antiangiogenic growth factors is a highly accepted mechanism in the pathogenesis of pregnancy-induced hypertension and proteinuria, which is clinically known as preeclampsia (PE). We investigated the effect of magnesium sulfate (MgSO4) therapy on vascular endothelial growth factor (VEGF), placental growth factor (PlGF), nitric oxide (NO) metabolites, soluble fm-like tyrosine kinase-1 (sFlt-1) and endoglin levels in PE rats and the effect of this treatment on the feto-maternal outcome. The PE group showed hypertension, proteinuria and decreased number and weight of live pups relative to the control group. This result was associated with increased sFlt-1, VEGF receptor-2 (VEGFR-2), VEGFR-3 and endoglin levels but decreased NO metabolites. MgSO4 therapy ameliorated systolic hypertension and proteinuria and decreased sFlt-1, VEGFR-2, VEGFR-3 and endoglin levels but increased NO metabolites in the treated group. Physiological and biochemical changes and improved pup weight and viability were observed in the treated group. The vasodilator action of MgSO4 and increased NO production are expected to increase placental blood flow and help fetal nutrition and development. Relief of placental ischemia decreases the production of antiangiogenic growth factors and restores the bioavailability of angiogenic factors (PlGF and VEGF). These changes resulted in better fetal outcome and an improved clinical picture of PE. These findings are promising and encourage further study of the mechanism of action of MgSO(4) to support its widespread use in the prevention and management of the etiopathological changes underlying the vast majority of the manifestations and complications of PE.

The vascular endothelial growth factor family in adverse pregnancy outcomes

BACKGROUND

Pre-eclampsia, small-for-gestational-age infants, preterm birth and recurrent miscarriage complicate a significant number of pregnancies. The vascular endothelial growth factor (VEGF) family of angiogenic growth factors is implicated in the pathophysiology of these complications. We aimed to elucidate the role of these angiogenic factors in placentation and to evaluate the predictive value of their protein concentrations and genetic variations in pregnancy complications.

METHODS

We performed a systematic search of PubMed, and retrieved original articles. The search included a combination of terms such as VEGF-A, placental growth factor (PlGF), kinase insert domain receptor, fms-like-tyrosine-kinase receptor 1, soluble fms-like-tyrosine-kinase receptor 1, pre-eclampsia, small-for-gestational-age infants, preterm birth, recurrent miscarriage, placenta, prediction and polymorphisms.

RESULTS

This review summarizes the current knowledge of the roles of the VEGF family in early placentation and of the abnormalities in maternal plasma and placental expression of angiogenic proteins in adverse pregnancy outcomes compared with normal pregnancy. PlGF and sFLT-1 in combination with other clinical and biochemical markers in late first or second trimester appear to predict early-onset pre-eclampsia with a high sensitivity and specificity. However, VEGF family proteins do not have sufficient power to accurately predict late-onset pre-eclampsia, small-for-gestational age pregnancies or preterm birth. Functional polymorphisms in these angiogenic genes are implicated in pregnancy complications, but their contribution appears to be minor.

CONCLUSIONS

Although the VEGF family has important roles in normal and complicated pregnancy, the current predictive value of the VEGF family as biomarkers appears to be limited to early-onset pre-eclampsia.