Placenta-derived angiogenic proteins and their contribution to the pathogenesis of preeclampsia

Tanshinol inhibits trophoblast cell migration and invasion by regulating Gadd45a in preeclampsia

OBJECTIVE

Tanshinol is an active constituent of Salvia miltiorrhiza that possesses anti-inflammatory, antioxidant, and antibacterial activities. Therefore, this study attempted to detect whether it has a role in the treatment of preeclampsia (PE).

METHODS

In this study, we explored the effect of tanshinol on the development of PE at the cellular level. The effect of tanshinol on cell proliferation was measured by colony formation and EdU assays. The migration, invasion, and in vitro angiogenesis of HTR-8/SVneo cells were detected by wound-healing, transwell, and tube formation assays, respectively. In addition, a PE cell model was established by overexpression of Gadd45a, and this cell model was assessed with the optimal concentration of tanshinol.

RESULTS

The results show that tanshinol enhanced proliferation, migration, invasion, and tube formation of HTR-8/SVneo cells in vitro. Furthermore, the reduction in proliferation, migration, invasion, and tube formation of cells by Gadd45a overexpression was partially reversed by tanshinol treatment. Tanshinol also inhibited the apoptosis of HTR-8/SVneo cells transfected with Gadd45a.

CONCLUSIONS

In summary, tanshinol promoted proliferation, migration, invasion, and tube formation and inhibited the apoptosis of HTR-8/SVneo cells. It may be a novel therapeutic compound to attenuate the development of PE.

Predictive value of the sFlt‑1/PlGF ratio in women with suspected preeclampsia: An update (Review)

Preeclampsia (PE) is a major complication of pregnancy with an incidence rate of 2‑8% and is a leading cause of maternal mortality and morbidity. The various consequences of severe preeclampsia for the fetus, neonate and child include intrauterine growth retardation (IUGR), fetal hypoxia, oligohydramnios, intrauterine fetal demise, increased perinatal mortality and morbidity, neurodevelopmental disorders and even irreversible brain damage (cerebral palsy). A number of studies have demonstrated that differences in maternal serum concentrations of angiogenic factors between preeclampsia and normotensive pregnancies can be used as biomarkers, either alone or in combination with other markers, to predict the development of PE. The presence in the maternal circulation of two proteins of placental origin, placental growth factor (PlGF) and soluble fms‑like tyrosine kinase 1 (sFlt‑1), has been shown to be of clinical value, as the sFlt‑1/PlGF ratio appears to be the optimal predictive tool for the development of PE. The measurement of their concentration in maternal serum in screening models, serves as predictive marker for the development of PE or IUGR later in gestation. However, further research is required to improve its clinical applicability and provide guidelines for its use worldwide to achieve more consistent clinical management of women with PE.

The role of immune cells and mediators in preeclampsia

Preeclampsia is a hypertensive disorder of major concern in pregnancy than can lead to intrauterine growth restriction, placental abruption and stillbirth. The pathophysiology of preeclampsia is multifactorial, including not only kidney dysfunction but also endothelial dysfunction, as the maternal endothelium becomes exposed to placental factors that are released into the circulation and increase systemic levels of vasoconstrictors, oxidative stress, anti-angiogenic factors and inflammatory mediators. Importantly, inflammation can lead to insufficient placental perfusion and low birthweight in offspring. Various innate and adaptive immune cells and mediators have been implicated in the development of preeclampsia, in which oxidative stress is associated with activation of the maternal inflammatory response. Immune cells such as regulatory T cells, macrophages, natural killer cells, and neutrophils are known to have major causative roles in the pathology of preeclampsia, but the contributions of additional immune cells such as B cells, inflammatory cytokines and anti-angiotensin II type 1 receptor autoantibodies are also now recognized. Immunological interventions, therefore, have therapeutic potential in this disease. Here, we provide an overview of the immune responses that are involved in the pathogenesis of preeclampsia, including the role of innate and adaptive immune cells and mediators.

CCL2: An important cytokine in normal and pathological pregnancies: A review

C-C motif ligand 2 (CCL2), also known as monocytic chemotactic protein 1 (MCP-1), is an integral chemotactic factor which recruits macrophages for the immune response. Together with its receptors (e.g., CCR2, ACKR1, and ACKR2), they exert noticeable influences on various diseases of different systems. At the maternal-fetal interface, CCL2 is detected to be expressed in trophoblasts, decidual tissue, the myometrium, and others. Meanwhile, existing reports have determined a series of physiological regulators of CCL2, which functions in maintaining normal recruitment of immunocytes, tissue remodeling, and angiogenesis. However, abnormal levels of CCL2 have also been reported to be associated with adverse pregnancy outcomes such as spontaneous abortion, preeclampsia and preterm labor. In this review, we concentrate on CCL2 expression at the maternal-fetal interface, as well as its precise regulatory mechanisms and classic signaling pathways, to reveal the multidimensional aspects of CCL2 in pregnancy.

Preeclampsia: state of art and future perspectives. A special focus on possible preventions

Preeclampsia (PE) is characterised by the new onset of hypertension after the 20th week of pregnancy, with or without proteinuria or hypertension that leads to end-organ dysfunction. Since the only definitive treatment is delivery, PE still represents one of the leading causes of preterm birth and perinatal mobility and mortality. Therefore, any strategies that aim to reduce adverse outcomes are based on early primary prevention, prenatal surveillance and prophylactic interventions. In the last decade, intense research has been focussed on the study of predictive models in order to identify women at higher risk accurately. To date, the most effective screening model is based on the combination of anamnestic, demographic, biophysical and maternal biochemical factors. In this review, we provide a detailed discussion about the current and future perspectives in the field of PE. We will examine pathogenesis, risk factors and clinical features. Moreover, recent developments in screening and prevention strategies, novel therapies and healthcare management strategies will be discussed.

The Role of Syncytin in Placental Angiogenesis and Fetal Growth

Background: Syncytin, a retroviral envelope protein, is specifically expressed on trophoblast cells and mediates formation of the syncytiotrophoblast through fusogenic activity. Decreased expression of Syncytin was found in fetal growth restriction placentas. Results: By generating an inducible knockout of the syncytin-a gene in mice, we show a specific disruption of placental angiogenesis with abnormal formation of two syncytiotrophoblast layers. Consistent with the defects observed in vivo, conditioned medium collected from trophoblast cells, following Syncytin-1 knockdown, contains lower expression of vascular endothelial growth factor and placental growth factor, and higher levels of soluble fms-like protein kinase-1 in BeWo and HTR-8/SVneo cells which related with suppressed PI3K/Akt/mTOR pathway, and is reduced in ability to induce tube formation by HUVECs. Conclusion: Syncytin participates in angiogenesis during placental development was first identified both in vivo and in vitro. Here, we give a new sight on understanding syncytin and pathophysiology of placenta related disease such as fetal growth restriction.

Placental lesions and differential expression of pro-and anti-angiogenic growth mediators and oxidative DNA damage marker in placentae of Ghanaian suboptimal and optimal health status pregnant women who later developed preeclampsia

Background

Angiogenic growth mediators (AGMs) and oxidative stress (OS) both play essential roles in normal placental vascular development and as such, placental alterations in these factors contribute to pre-eclampsia (PE). Suboptimal health status (SHS), an intermediate between health and disease, has been associated with imbalanced AGMs and OS biomarkers. Thus, SHS pregnant women may be at increased risk of developing PE and may present abnormal placental alteration and expression of AGMs and OS compared to optimal health status (OHS) pregnant women. We examined the histopathological morphology, immunohistochemical expression of AGMs antibodies and oxidative DNA damage marker in the placentae of SHS and OHS pregnant women who developed early-onset PE (EO-PE) and late-onset (LO-PE) compared to normotensive pregnancy (NTN-P).

Methods

This nested case-control study recruited 593 singleton normotensive pregnant women at baseline (10–20 weeks gestation) from the Ghanaian Suboptimal Health Status Cohort Study (GHOACS) undertaken at the Komfo Anokye Teaching Hospital, Ghana. Socio-demographic, clinical and obstetrics data were collected, and a validated SHS questionnaire-25 (SHSQ-25) was used in classifying participants into SHS (n = 297) and OHS (n = 296). Participants were followed until the time of PE diagnosis and delivery (32–42 weeks gestation). Blood samples were collected at the two-time points and were assayed for AGMs; soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PIGF), vascular endothelial growth factor-A (VEGF-A), and soluble endoglin (sEng), and OS biomarkers; 8-hydroxydeoxyguanosine (8-OHdG), 8-epiprostaglandinF2-alpha (8- epi-PGF2α) and total antioxidant capacity (TAC) using ELISA. Placental samples were collected for histopathological and immunohistochemical analysis.

Results

Of the 593 pregnant women, 498 comprising 248 SHS and 250 OHS women returned for delivery and were included in the final analysis. Of the 248 SHS women, 56, 97 and 95 developed EO-PE, LO-PE and NTN-P, respectively, whereas 14, 30 and 206 of the 250 OHS mothers developed EO-PE, LO-PE and NTN-P, respectively. At baseline, SHS_NTN pregnant women had a significant imbalance in AGMs and OS biomarkers compared to OHS_NTN pregnant women (p<0.0001). At the time of PE diagnosis, SHS_NTN-P women who developed EO-PE, LO-PE, and NTN-P had lower serum levels of P1GF, VEGF-A and TAC and correspondingly higher levels of sEng, sFlt-1, 8-epiPGF2α, and 8-OHdG than OHS-NTN-P women who developed EO-PE and LO-PE, NTN-P (p<0.0001). A reduced placental size, increased foetal/placental weight ratio, and a significantly higher proportion of fibrinoid necrosis, infarction, villous fibrin, syncytial knots, calcification, chorangiosis, tunica media/vascular wall hypertrophy and chorioamnionitis was associated with the SHS group who developed PE (EO-PE>LO-PE) more than OHS groups who developed PE (EO-PE>LO-PE) when all were compared to NTN-P (p<0.0001). The intensity of antibody expression of PIGF and VEGF-A were significantly reduced, whereas Flt-1, Eng and 8-OHdG were significantly increased in placentae from SHS-pregnant women who developed EO-PE>LO-PE more than OHS- pregnant women who developed EO-PE>LO-PE when all were compared to NTN-P (p<0.0001).

Conclusion

Increased lesions, oxidative DNA damage, and imbalanced expression between pro-and anti-AGMs are associated more with SHS-embodied PE placentae rather than OHS-embodied PE subtypes, thus potentially allowing differential evaluation of PE.

Association between placental implantation abnormalities and hypertensive disorders of pregnancy

AIM

This study aimed to investigate the association between placental implantation abnormalities (PIAs) and gestational hypertension-preeclampsia (GH-PE) in pregnant women.

METHODS

Patients were recruited from 2010 to 2019 into this retrospective study at the International Peace Maternity & Child Health Hospital. PIAs were classified as follows: placenta previa (PP), low-lying placenta (LP), placenta accreta, and placenta adherence (PA). Logistic regression models were constructed to analyze the associations between placental abnormalities and GH-PE. Propensity score matching (PSM) was conducted to reduce confounders. The relationship between PP with placenta accreta spectrum (PAS) and GH-PE were assessed.

RESULTS

In total, 5527 women were recruited, and 2614 women had an abnormal placenta (992 with LP; 749 with PP 839 and PA; and 34 with placenta accreta). There were 296 patients with GH-PE in those groups. After adjustments for confounding factors, women with PP had a lower risk of PE (odds ratio [OR]: 0.43; 95% confidence interval [CI]: 0.19-0.86, p = 0.025) than those in the control group. Women with PA had a higher risk of GH-PE (OR: 1.45; 95% CI: 1.05-1.99, p = 0.022). In addition, we categorized PP into marginal, complete, and partial PP and investigated these associations. We found a lower risk of PE in complete PP (OR: 0.09, 95% CI: 0.01-0.44, p = 0.020) than in marginal or partial PP. There was no significant difference regarding GH-PE in the PP with PAS group (OR = 0.67, 95% CI: 0.82-2.34, p = 0.525).

CONCLUSION

PP, especially complete PP, is associated with a lower risk of PE. PA is associated with higher risks of GH-PE.

Early gestational profiling of oxidative stress and angiogenic growth mediators as predictive, preventive and personalised (3P) medical approach to identify suboptimal health pregnant mothers likely to develop preeclampsia

BACKGROUND

Pregnant women, particularly in developing countries are facing a huge burden of preeclampsia (PE) leading to high morbidity and mortality rates. This is due to delayed diagnosis and unrecognised early targeted preventive measures. Adapting innovative solutions via shifting from delayed to early diagnosis of PE in the context of predictive diagnosis, targeted prevention and personalisation of medical care (PPPM/3 PM) is essential. The subjective assessment of suboptimal health status (SHS) and objective biomarkers of oxidative stress (OS) and angiogenic growth mediators (AGMs) could be used as new PPPM approach for PE; however, these factors have only been studied in isolation with no data on their combine assessment. This study profiled early gestational biomarkers of OS and AGMs as 3 PM approach to identify SHS pregnant mothers likely to develop PE specifically, early-onset PE (EO-PE) and late-onset PE (LO-PE).

METHODS

A prospective cohort of 593 singleton normotensive pregnant (NTN-P) women were recruited at 10-20th (visit 1) and followed from 21 weeks gestation until the time of PE diagnosis and delivery. At visit 1, SHS was assessed using SHS questionnaire-25 (SHSQ-25) and women were classified as SHS and optimal health status (OHS). Biomarkers of OS (8-hydroxy-2-deoxyguanosine [8-OHdG], 8-epi-prostaglansinF2alpha [8-epi-PGF2α] and total antioxidant capacity [TAC]) and AGMs (vascular endothelial growth factor [VEGF-A], soluble Fms-like tyrosine kinase-1 [sFlt-1], placental growth factor [PlGF] and soluble endoglin [sEng]) were measured at visit 1 and time of PE diagnosis.

RESULTS

Of the 593 mothers, 498 (248 SHS and 250 OHS) returned for delivery and were included in the final analysis. Fifty-six, 97 and 95 of the 248 SHS mothers developed EO-PE, LO-PE and NTN-P respectively, versus 14 EO-PE, 30 LO-PE and 206 NTN-P among the 250 OHS mothers. At the 10-20th week gestation, unbalanced levels of OS and AGMs were observed among SHS women who developed EO-PE than LO-PE compared to NTN-P women (p < 0.0001). The combined ratios of OS and AGMs, mainly the levels of 8-OHdG/PIGF ratio at 10-20th week gestation yielded the best area under the curve (AUC) and highest relative risk (RR) for predicting SHS-pregnant women who developed EO-PE (AUC = 0.93; RR = 6.5; p < 0.0001) and LO-PE (AUC = 0.88, RR = 4.4; p < 0.0001), as well as for OHS-pregnant women who developed EO-PE (AUC = 0.89, RR = 5.6; p < 0.0001) and LO-PE (AUC = 0.85; RR = 5.1; p < 0.0001).

CONCLUSION

Unlike OHS pregnant women, SHS pregnant women have high incidence of PE coupled with unbalanced levels of OS and AGMs at 10-20 weeks gestation. Combining early gestational profiling of OS and AGMs created an avenue for early differentiation of PE subtypes in the context of 3 PM care for mothers at high risk of PE.

NRP1 and MMP9 are dual targets of RNA-binding protein QKI5 to alter VEGF-R/ NRP1 signalling in trophoblasts in preeclampsia

Preeclampsia (PE) is characterized by placental ischemia and hypoxia, resulting in abnormal casting of the uterine spiral artery, which is mainly caused by insufficient trophoblastic cell infiltration. A reduction in levels of growth factor-based signalling via Neuropilin-1 (NRP1) has been shown to contribute to dysfunctional trophoblast development. In this study, we showed that the RNA-binding protein, QKI5, regulated NRP1 expression and significantly improved trophoblast proliferation in vitro and in vivo. QKI5 and NRP1 expressions were significantly reduced in human PE placentas and in trophoblasts during hypoxia. Overexpression of these factors significantly improved cell proliferation and migration in vitro, in contrast to a decrease upon siRNA knockdown of QKI5 and NRP1 in HTR-8/SVneo cells. Using RIP and RNA pull-down assays, we further showed that QKI5 directly interacted with the 3'-UTR region of NRP1, to mediate cell proliferation and migration via matrix metalloprotease-9. Further, similar to NRP1, QKI5 also targets matrix metalloproteinase 9 (MMP9) involved in secretion of growth factors and its effects can be counteracted by NRP1 overexpression. In vivo studies using a PE mouse model revealed that QKI5 overexpression alleviated PE-related symptoms such as elevated blood pressure and proteinuria. Taken together, we found that QKI5 was a novel regulator, of VEGF-R/NRP1 signalling pathway functioning in trophoblast proliferation and migration, resulting in major contributors to the pathogenesis of PE. While careful evaluation of the broad implications of QKI5 expression is still necessary, this study identified QKI5 as a promising target for treatment strategies in acute PE patients.

Reduction of serum-induced endothelial STAT3(Y705) activation is associated with preeclampsia

OBJECTIVES

Preeclampsia is associated with maternal morbidity and mortality during pregnancy, and also an increased cardiovascular disease (CVD) risk later in life. During preeclampsia, alterations in secreted placental factors leading to systemic maternal endothelial dysfunction are evident. However, little is known about the associated endothelial intracellular signaling. STAT3 is a latent cytoplasmic transcription factor involved in endothelial cell differentiation, survival, and angiogenesis. We aimed to test if preeclampsia and preeclampsia-related placental factors could alter serum-induced STAT3(Y705) activation in endothelial cells. Furthermore, if altered serum-induced endothelial STAT3 (Y705) activation is related to post-preeclamptic CVD risk.

STUDY DESIGN

HUVECs were used as a model of maternal endothelium. Experiments entailed addition of 20% human pregnancy serum as well as addition of recombinant PlGF, sFLT1 and VEGF-A_165a to the cells.

MAIN OUTCOME MEASURES

Levels of pSTAT3(Y705) related to STAT3 levels were evaluated by immunoblotting analysis.

RESULTS

Our results show that preeclamptic serum induces significantly lower STAT3(Y705) phosphorylation compared with uncomplicated pregnancy serum (P = 0.0089) in endothelial cells. Furthermore, STAT3(Y705) phosphorylation was not changed upon addition of PlGF, sFLT1, or VEGF-A_165a together with pregnancy sera compared with sera alone. Finally, sera from women with previous preeclampsia and current hypertension and carotid atherosclerotic plaques show significantly lower STAT3(Y705) phosphorylation capabilities compared with healthy women with previous uncomplicated pregnancies 8-18 years after deliveries (P = 0.029).

CONCLUSIONS

Reduction in serum-induced endothelial STAT3(Y705) activation may play an important role in the preeclampsia-associated endothelial dysfunction. Additionally, reduced endothelial STAT3(Y705) phosphorylation may contribute to increased post-preeclamptic CVD risk 8-18 years after delivery.

Clinical implications of placenta-derived angiogenic/anti-angiogenic biomarkers in pre-eclampsia

Pre-eclampsia (PE) is a devastating systemic disease which results in maternal hypertension with multi-organ failure due to angiogenic imbalance, characterized by lack of circulating pro-angiogenic factors and excess of anti-angiogenic factors. These factors are crucial for understanding the pathophysiology of PE since they serve as a critical link from placental dysfunction to the clinical syndrome of systemic endothelial dysfunction in the disease. Moreover, utilizing these angiogenic/anti-angiogenic biomarkers can be helpful in risk stratifying and the early detection of PE, which allows for timely intervention to improve maternal and neonatal outcomes. In this review, we summarize updated perspectives of the angiogenic imbalance in PE with detailed characterization of key factors involved in the pathogenesis and how the developed biomarkers can be used in clinical settings as diagnostic tools and as possible therapeutic targets of PE.

Placental growth factor and Fms related tyrosine kinase-1 are hypomethylated in preeclampsia placentae

Aim: This study aims to examine the DNA methylation (DNAm) and expression patterns of genes associated with placental angiogenesis in preeclampsia. Materials & methods: DNAm and expression were examined in normotensive (n = 100) and preeclampsia (n = 100) women using pyrosequencing and quantitative real-time PCR respectively. Results: Hypomethylation at several CpGs was observed in PlGF and FLT-1 in women with preeclampsia compared to normotensive controls. PlGF expression was lower in women with preeclampsia while FLT-1 expression was comparable. DNAm at various CpGs was negatively correlated with expression in both the genes and were associated with maternal blood pressure and birth outcomes. Conclusion: DNAm and expression of angiogenic factors in placentae are differentially regulated in preeclampsia and influence birth outcomes.

The Multifaced Actions of Curcumin in Pregnancy Outcome

Curcumin, also known as diferuloylmethane, is the main polyphenolic substance present in the rhizomes of Curcuma longa L. This plant showed many beneficial effects and has been used since ancient times for both food and pharmaceutical purposes. Due to its pleiotropic functions, curcumin consumption in the human diet has become very common thanks also to the fact that this natural compound is considered quite safe as it does not have serious side effects. Its functions as an anti-inflammatory, anti-oxidant, neuroprotective, immunomodulatory, anti-toxicant, anti-apoptotic, and anti-diabetic compound are already known and widely demonstrated. There are numerous studies concerning its effects on various human pathologies including cancer, diabetes and arthritis while the studies on curcumin during pregnancy have been performed only in animal models. Data concerning the role of curcumin as anti-inflammatory compound suggest a possible use of curcumin in managing pregnancy complications such as Preeclampsia (PE), Gestational Diabetes Mellitus (GDM), Fetal Growth Restriction (FGR), PreTerm Birth (PTB), and exposure to toxic agents and pathogens. The aim of this review is to present data to support the possible use of curcumin in clinical trials on human gestation complications.

Roles of aryl hydrocarbon receptor in endothelial angiogenic responses†

Aryl hydrocarbon receptor (AhR) is a transcription factor, which can be activated by a plethora of structure-diverse ligands. Historically, AhR is known for its involvements in regulation of metabolism of xenobiotics. However, normal physiological roles of AhR have been defined in other essential biological processes, including vascular growth and function, reproduction, and immunoresponses. In contrast, aberrant expression and activation of the AhR signaling pathway occur in a variety of human diseases, many of which (e.g., preeclampsia, atherosclerosis, and hypertension) could be associated with endothelial dysfunction. Indeed, emerging evidence has shown that either exogenous or endogenous AhR ligands can induce endothelial dysfunction in either an AhR-dependent or AhR-independent manner, possibly reliant on the blood vessel origin (artery and vein) of endothelial cells. Given that the AhR signaling pathway has broad impacts on endothelial and cardiovascular function, AhR ligands, AhR, and their downstream genes could be considered novel therapeutic targets for those endothelial-related diseases. This review will discuss the current knowledge of AhR's mediation on endothelial function and potential mechanisms underlying these actions with a focus on placental endothelial cells.

Potential Protein Biomarkers for Preeclampsia

To date, the etiology of preeclampsia (PE) has not been clarified and the specific treatment is lacking; hence, early prediction and prevention are very important. Thus, a large number of biomarkers that may be associated with PE have been identified based on proteomics to provide a reference for the prediction of PE and for the understanding of the pathological mechanisms of this disease. This article briefly summarizes the application of proteomics in PE and the potential protein biomarkers to provide a reference for other researchers.

Pericytes Contribute to Dysfunction in a Human 3D Model of Placental Microvasculature through VEGF-Ang-Tie2 Signaling

Placental vasculopathies are associated with a number of pregnancy-related diseases, including pre-eclampsia (PE)-a leading cause of maternal-fetal morbidity and mortality worldwide. Placental presentations of PE are associated with endothelial dysfunction, reduced vessel perfusion, white blood cell infiltration, and altered production of angiogenic factors within the placenta (a candidate mechanism). Despite maintaining vascular quiescence in other tissues, how pericytes contribute to vascular growth and signaling in the placenta remains unknown. Here, pericytes are hypothesized to play a detrimental role in the pathogenesis of placental vascular growth. A perfusable triculture model is developed, consisting of human endothelial cells, fibroblasts, and pericytes, capable of recapitulating growth and remodeling in a system that mimics inflamed placental microvessels. Placental pericytes are shown to contribute to growth restriction of microvessels over time, an effect that is strongly regulated by vascular endothelial growth factor and Angiopoietin/Tie2 signaling. Furthermore, this model is capable of recapitulating essential processes including tumor necrosis factor alpha (TNFα)-mediated vascular leakage and leukocyte infiltration, both important aspects associated with placental PE. This placental vascular model highlights that an imbalance in endothelial-pericyte crosstalk can play a critical role in the development of vascular pathology and associated diseases.

Serum Levels of Angiogenic Factors Distinguish Between Women with Preeclampsia and Normotensive Pregnant Women But Not Severity of Preeclampsia in an Obstetric Center in Turkey

Background

This study aimed to compare serum levels of vascular endothelial growth factor (VEGF) and the VEGF receptors, VEGFR-1 and VEGFR-2, free placental growth factor (fPGF), endostatin, and serum pregnancy-associated plasma protein-A (PAPP-A) levels in women with mild and severe preeclampsia and healthy pregnant women.

Material/Methods

A included patients diagnosed with mild preeclampsia (n=32), severe preeclampsia (n=32), and healthy pregnant women (n=24). Serum levels of VEGF-A, VEGFR-1, VEGFR-2, fPGF, endostatin, and PAPP-A levels were measured by enzyme-linked immunosorbent assay (ELISA).

Results

In women with mild and severe preeclampsia, the gestation age at birth and birth weight were found to be significantly lower than the control group (p<0.001). Serum levels of endostatin, VEGFR-1, and VEGF-A levels were significantly increased in pregnant women with preeclampsia compared with healthy pregnant women (p<0.001). Serum levels of PAPP-A, VEGFR-2, and fPGF were significantly higher in healthy pregnant women when compared with women with preeclampsia (p=0.024, p<0.001, and p<0.001, respectively), but there were no significant differences between women with mild and severe preeclampsia.

Conclusions

Reduced serum levels of the angiogenic factors PAPP-A, VEGFR-2, and fPGF distinguished between women with preeclampsia and normotensive pregnant women but did not significantly distinguish between mild and severe preeclampsia.

Diversity in human placental microvascular endothelial cells and macrovascular endothelial cells

Angiogenesis is fundamental to normal placental development, and aberrant angiogenesis contributes substantially to placental pathologies. Placental angiogenesis is a pivotal process that plays a key mechanistic role in the elaboration of the placental villous tree, which is mainly taken by human placental microvascular endothelial cells (HPMECs), present in the fetal capillaries of chorionic villi, and macrovascular human umbilical vein endothelial cells (HUVECs) also play a role in this process. These are the two types of endothelial cells that form the placenta and differ in morphology and function. The placental vasculature represents a distinct territory that is highly specialized in structure and function. To distinguish the differences between HPMECs and HUVECs, we isolated HPMECs by paramagnetic particle separation and HUVECs through trypsinization and validated their characteristics. Then, we examined their response to fibroblast growth factor 2 (FGF2), vascular endothelial growth factor (VEGF) and endocrine-gland-derived vascular endothelial growth factor (EG-VEGF), as well as the underlying signaling mechanisms and their transcriptomes. We found that cultured HPMECs and HUVECs took up DiI-Ac-LDL and formed capillary-like tube structures on Matrigel. HPMECs and HUVECs had different expressions of eNOS, PROKR1 and PROKR2, and these characteristics substantiate the endothelial nature of cultured cells. FGF2 and VEGF stimulated the proliferation and migration of HPMECs and HUVECs via activation of PI3K/AKT1 and MEK1/MEK2/ERK1/ERK2. Interestingly, EG-VEGF increased the proliferation and migration of HPMECs via only MEK1/MEK2/ERK1/ERK2 and not PI3K/AKT1. Microarray analysis showed that there were some differentially expressed genes between HPMECs and HUVECs. Gene ontology analysis indicated that the differentially expressed genes were highly related to G-protein coupled receptor signaling pathway, angiogenesis, L-lysine transmembrane transport and blood vessel remodeling. These data provided evidence of heterogeneity between microvascular HPMECs and macrovascular HUVECs that most likely reflected significant differences in endothelial cell function in the two different cellular environments.

Angiogenic and antiangiogenic factors in preeclampsia

BACKGROUND

Pre-eclampsia is a multifactorial hypertensive disorder that is triggered by placental insufficiency and that accounts for up to 15% of maternal deaths. In normal pregnancies, this process depends on the balance between the expression of angiogenic factors and antiangiogenic factors, which are responsible for remodeling the spiral arteries, as well as for neoangiogenesis and fetal development.

PURPOSE

The aim of this review is to discuss the main scientific findings regarding the role of angiogenic and antiangiogenic factors in the etiopathogenesis of preeclampsia.

METHODS

An extensive research was conducted in the Pubmed database in search of scientific manuscripts discussing potential associations between angiogenic and antiangiogenic factors and preeclampsia. Ninety-one papers were included in this review.

RESULTS

There is an increased expression of soluble fms-like tyrosine kinase receptor and soluble endoglin in pre-eclampsia, as well as reduced placental expression of vascular endothelial growth factor and placental growth factor. Systemic hypertension, proteinuria and kidney injury - such as enlargement and glomerular fibrin deposit, capillary occlusion due to edema, and hypertrophy of endocapillary cells - are some of these changes. The complex etiopathogenesis of preeclampsia instigates research of different biomarkers that allow for the early diagnosis of this entity, such as vascular endothelial growth factor, placental growth factor, soluble fms-like tyrosine kinase receptor, soluble endoglin, placental glycoprotein pregnancy-associated plasma protein-A and protein 13.

CONCLUSION

Even though it is possible to establish an efficient and effective diagnostic tool, three key principles must be observed in the management of preeclampsia: prevention, early screening and treatment.

Vitamin D Supplementation Prevents Placental Ischemia Induced Endothelial Dysfunction by Downregulating Placental Soluble FMS-Like Tyrosine Kinase-1

Maternal vitamin D deficiency in pregnancy has been associated with an increased risk of preeclampsia. Vascular endothelial dysfunction is a major phenotype of pregnancies with preeclampsia, contributing to increased maternal hypertension and proteinuria. We sought to determine whether vitamin D supplementation would alleviate preeclampsia associated endothelial dysfunction and explore the underlying mechanism using the reduced uterine perfusion pressure (RUPP) rat model. RUPP operated rats were supplemented with 1,25(OH)₂D (RUPP+VD) on day 1, 7, and 14 of pregnancy by subcutaneous injection. On day 19 of pregnancy, after the measurement of blood pressure and urine collection, maternal blood serum and placenta samples were collected. 1,25(OH)₂D treatment significantly improved endothelial dysfunction by reducing apoptosis and increasing nitric oxide (NO) production in blood vessels of RUPP operated rats compared to untreated RUPP rats. 1,25(OH)₂D significantly down-regulated the expression of placental soluble FMS-like tyrosine kinase-1 (sFlt-1) in RUPP rats. Furthermore, the circulating sFlt-1 levels in maternal serum were positively correlated with the expression of placental sFlt-1 and were restored to a normal pregnant level by 1,25(OH)₂D treatment in RUPP rats. Incubation of endothelial cell line with rat serum from RUPP+VD group significantly increased NO production and decreased caspase-3 activity compared with serum from untreated RUPP rats. Moreover, neutralization of sFlt-1 using the specific antibody mimicked the effect of 1,25(OH)₂D, which abolished the deleterious effect of RUPP rat's serum on NO production and apoptosis. These results suggest that vitamin D supplementation is protective against RUPP induced endothelial dysfunction by downregulating placental sFlt-1, which can possibly alleviate preeclampsia associated symptoms.

A Single Sphingomyelin Species Promotes Exosomal Release of Endoglin into the Maternal Circulation in Preeclampsia

Preeclampsia (PE), an hypertensive disorder of pregnancy, exhibits increased circulating levels of a short form of the auxillary TGF-beta (TGFB) receptor endoglin (sENG). Until now, its release and functionality in PE remains poorly understood. Here we show that ENG selectively interacts with sphingomyelin(SM)-18:0 which promotes its clustering with metalloproteinase 14 (MMP14) in SM-18:0 enriched lipid rafts of the apical syncytial membranes from PE placenta where ENG is cleaved by MMP14 into sENG. The SM-18:0 enriched lipid rafts also contain type 1 and 2 TGFB receptors (TGFBR1 and TGFBR2), but not soluble fms-like tyrosine kinase 1 (sFLT1), another protein secreted in excess in the circulation of women with PE. The truncated ENG is then released into the maternal circulation via SM-18:0 enriched exosomes together with TGFBR1 and 2. Such an exosomal TGFB receptor complex could be functionally active and block the vascular effects of TGFB in the circulation of PE women.

FLT1 and transcriptome-wide polyadenylation site (PAS) analysis in preeclampsia

Maternal symptoms of preeclampsia (PE) are primarily driven by excess anti-angiogenic factors originating from the placenta. Chief among these are soluble Flt1 proteins (sFlt1s) produced from alternatively polyadenylated mRNA isoforms. Here we used polyadenylation site sequencing (PAS-Seq) of RNA from normal and PE human placentae to interrogate transcriptome-wide gene expression and alternative polyadenylation signatures associated with early-onset PE (EO-PE; symptom onset < 34 weeks) and late-onset PE (LO-PE; symptom onset > 34 weeks) cohorts. While we observed no general shift in alternative polyadenylation associated with PE, the EO-PE and LO-PE cohorts do exhibit gene expression profiles distinct from both each other and from normal placentae. The only two genes upregulated across all transcriptome-wide PE analyses to date (microarray, RNA-Seq and PAS-Seq) are NRIP1 (RIP140), a transcriptional co-regulator linked to metabolic syndromes associated with obesity, and Flt1. Consistent with sFlt1 overproduction being a significant driver of clinical symptoms, placental Flt1 mRNA levels strongly correlate with maternal blood pressure. For Flt1, just three mRNA isoforms account for > 94% of all transcripts, with increased transcription of the entire locus driving Flt1 upregulation in both EO-PE and LO-PE. These three isoforms thus represent potential targets for therapeutic RNA interference (RNAi) in both early and late presentations.

Pre-eclampsia and the risk of retinopathy of prematurity in preterm infants with birth weight <1500 g and/or <31 weeks' gestation

Objective

To evaluate the relationship between pre-eclampsia and development of retinopathy of prematurity (ROP) in infants with birth weight of <1500 g and/or gestation <31 weeks.

Methods

A retrospective cohort study comprising infants born to mothers with pre-eclampsia between January 2007 and June 2010 at a single tertiary care centre. Their ROP outcome was compared with infants born to the next two normotensive mothers with a ±1 week gestational age difference. Pearson χ² test was used for categorical variables and Mann-Whitney U test was used for continuous variables. Multivariable regression was used to estimate the OR of ROP with prenatal pre-eclampsia exposure and adjust for confounders.

Results

Of the 97 infants in the pre-eclampsia group, 27 (27%) developed ROP and of the 185 infants in the normotensive group, 50 (27%) developed ROP. On multivariable regression modelling, pre-eclampsia was not a risk factor for the development of ROP (OR 1.4, 95% CI 0.46 to 4.1). Gestational age, intrauterine growth restriction and blood transfusion were significant risk factors for the development of ROP.

Conclusions

In our cohort, pre-eclampsia was not a significant risk factor for the development of ROP. Intrauterine growth restricted infants of pre-eclamptic and normotensive mothers were at higher risk of ROP.

Mild anemia during pregnancy upregulates placental vascularity development

The connection between maternal hematological status and pregnancy outcome has been shown by many independent researchers. Attention was initially focused on the adverse effects of moderate and severe anemia. Interestingly, some studies revealed that mild anemia was associated with optimal fetal development and was not affecting pregnancy outcome. The explanation for this phenomenon became a target for scientists. Hemodilution, physiologic anemia and relative decrease in hemoglobin concentration are the changes observed during pregnancy but they do not explain the reasons for the positive influence of mild anemia on a fetomaternal unit. It is hypothesized that hemodilution facilitates placental perfusion because blood viscosity is reduced. Subsequently, it may lead to a decline in hemoglobin concentration. Anemia from its definition implies decreased oxygen carrying capacity of the blood and can result in hypoxemia and even hypoxia, which is a common factor inducing new blood vessels formation. Therefore, we raised the hypothesis that the lowered hemoglobin concentration during pregnancy may upregulate vascular growth factor receptors expression such as VEGFR-1 (Flt-1) and VEGFR-2 (FLK-1/KDR). Consecutively, increased fetoplacental vasculogenesis and angiogenesis provide further expansion of vascular network development, better placental perfusion and hence neither fetus nor the mother are affected.

Association between Placental Lesions, Cytokines and Angiogenic Factors in Pregnant Women with Preeclampsia

Preeclampsia (PE) is considered the leading cause of maternal and perinatal morbidity and mortality. The placenta seems to play an essential role in this disease, probably due to factors involved in its formation and development. The present study aimed to investigate the association between placental lesions, cytokines and angiogenic factors in pregnant women with preeclampsia (PE). We evaluated 20 normotensive pregnant women, 40 with early-onset PE and 80 with late-onset PE. Placental samples were analyzed for histopathology, immunohistochemistry and determination of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-10 (IL-10), transforming growth factor-beta 1 (TGF-β₁), tumor necrosis factor-alpha (TNF-α), placental growth factor (PlGF), vascular endothelial growth factor (VEGF), fms-like tyrosine-kinase-1 (Flt-1) and endoglin (Eng) levels. Higher percentages of increased syncytial knots and increased perivillous fibrin deposits, and greater levels of TNF-α, TGF-β1and Flt-1 were detected in placentas from early-onset PE. Levels of IL-10, VEGF and PlGF were decreased in PE versus normotensive placentas. Both the TNF-α/IL-10 and sFlt-1/PlGF ratios were higher in placental homogenate of early-onset PE than late-onset PE and control groups. The more severe lesions and the imbalance between TNF-α/IL-10 and PlGF/sFlt-1 in placentas from early-onset PE allows differentiation of early and late-onset PE and suggests higher placental impairment in early-onset PE.

Increased levels of serum clusterin is associated with intrauterine growth restriction and adverse pregnancy outcomes in preeclampsia

AIM

Our aim was to investigate serum clusterin levels in preeclampsia and to determine whether any changes in clusterin levels are useful in distinguishing the presence of concomitant intrauterine growth restriction (IUGR) and in predicting adverse pregnancy outcomes.

METHODS

A prospective case-control study was carried out which included 86 pregnant women (47 patients with preeclampsia and 39 healthy controls). Maternal serum samples obtained from all participants and clusterin levels were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared with controls, women with preeclampsia had significantly higher clusterin levels (mean 83.8±23.6 vs. 119.2±40.5, P<0.01). Further analysis revealed the highest clusterin levels were in patients with preeclampsia and IUGR (P<0.001). According to the receiver operating characteristic (ROC) analysis performed for the predictive value of clusterin levels for adverse maternal outcomes, the area under the curve (AUC) was 0.738 (95% CI: 0.616-0.859). The best clusterin cut-off value in predicting adverse maternal outcomes was 102.6 pg/mL with 75% sensitivity and 66% specifity. Multivariable logistic regression analysis revealed serum clusterin levels of >102.6 pg/mL was independently associated with preeclampsia (OR: 6.18, 95% CI: 2.41-15.9) and maternal adverse outcomes (OR: 5.13, 95% CI: 2.01-13.1) and also clusterin levels higher than 117.4 pg/mL were associated with adverse neonatal outcomes (OR: 5.02, 95% CI: 1.04-24.3).

CONCLUSIONS

The current study suggests that increased levels of clusterin is associated with IUGR and probably predictive for adverse pregnancy outcomes in preeclampsia.

Expression of factors involved in the regulation of angiogenesis in the full-term human placenta: Effects of in vitro fertilization

The effects of assisted reproductive technologies (ARTs) on the safety of pregnancy and the resulting offspring remain controversial. Studies of placental functions, especially vasculogenesis and angiogenesis, in pregnancies established through ART are helpful for furthering our understanding of the safety of ART. This study compares the expression profiles of angiogenic factors in human term placentas obtained from natural (NAT) pregnancies vs. placentas obtained from pregnancies that resulted from ART. Term placentas were obtained from women who underwent an ART procedure (n=4), and these were compared with term placentas that were obtained from women who had experienced a spontaneous pregnancy (controls, n=4). An array analysis was performed using the Human Angiogenesis Antibody Array to detect 43 angiogenic factors and to identify which of these factors were differentially expressed between the two groups. The expression of six of these factors was greater in the ART group than in the NAT group. The levels of four of them, including vascular endothelial growth factor receptor-3 (VEGFR3), basic fibroblast growth factor (bFGF), interferon gamma (IFNG) and matrix metalloproteinase 1 (MMP1), were quantified using western blot analysis. These factors were examined using immunohistochemistry and microscopy in vascular endothelial cells or the cytoplasm and membranes of syncytiotrophoblast cells. Our finding that selected angiogenic factors exhibit altered expression profiles in ART placentas might be significant when evaluating ART safety.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Placental NRP1 and VEGF expression in pre-eclamptic women and in a homocysteine-treated mouse model of pre-eclampsia

OBJECTIVES

To investigate the expression levels of neuropilin 1 (NRP1) and vascular endothelial growth factor (VEGF) in the placentas of women with pre-eclampsia (PE), determine whether homocysteine (Hcy) contributes to the development of PE in mice, and detect alterations in placental NRP1 and VEGF in Hcy-treated mice.

STUDY DESIGN

Placental tissue samples were obtained from 16 patients with and without PE. Using reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, the expression levels of NRP1 and VEGF in PE and control placental tissues were examined. Immunohistochemical (IHC) assay was used to detect the localization of NRP1 and VEGF proteins. Pregnant mice were treated with DL-Hcy on embryonic day 7.5. The symptoms of the treated mice were examined. The expression levels of Ddah1, Ddah2, eNos, Cbs and Cse were determined by quantitative RT-PCR to study the possible mechanism of hyperhomocysteinemia (HHcy). Nrp1 and Vegf expression levels in the placentas of treated mice were measured by quantitative RT-PCR, western blot analysis and IHC.

RESULTS

NRP1 and VEGF were expressed at lower levels in women with PE compared with control women. The immunoreactivity of NRP1 was detected in villous trophoblast cells and villous capillary endothelial cells (ECs). Immunoreactive VEGF was observed mainly in vascular ECs within the villi. The pregnant mice treated with DL-Hcy showed PE-like symptoms such as higher systolic blood pressure and proteinuria in late pregnancy. Compared with the control mice, Ddah1, Ddah2 and eNos mRNA were expressed at lower levels, and Cbs and Cse mRNA were expressed at significantly higher levels in the placentas of the Hcy-treated group. Expression levels of Nrp1 and Vegf in mice placentas were decreased in the Hcy-treated group.

CONCLUSIONS

DL-Hcy can induce PE-like symptoms in mice. Both placental NRP1 and VEGF were expressed at lower levels in women with PE and Hcy-treated mice, which may contribute to endothelial damage.

Ischemic placental syndrome--prediction and new disease monitoring

The last decade has seen an improved understanding of the cause of the development of pathologies such as gestational hypertension, preeclampsia, intrauterine growth restriction, intrauterine fetal death or placental abruption. Nowadays, we know that most conditions within this group share the same pathogenesis, the cause of which is placental ischemia. The following review is an attempt to propose a new method for prediction, diagnosis and--above all--appropriate monitoring of pregnant women and fetuses developing the ischemic placental syndrome with the use of tests that are new but yet widely available in clinical diagnosis. They are closely related to the condition's pathogenesis, therefore their elevated levels may predate clinical symptoms, and--most importantly--they correlate with syndrome aggravation and the occurrence of complications. Perhaps, the new look will allow us to improve perinatal results by reducing mortality and severe complications in pregnant women and fetal deaths resulting from sudden intrauterine fetal death or placental abruption.