Placental disease and the maternal syndrome of preeclampsia: missing links?

Ghrelin alleviates placental dysfunction by down-regulating NF-κB phosphorylation in LPS-induced rat model of preeclampsia

In our previous study, we uncovered that ghrelin promotes angiogenesis in human umbilical vein endothelial cells (HUVECs) in vitro by activating the Jagged1/Notch2/VEGF pathway in preeclampsia (PE). However, the regulatory effects of ghrelin on placental dysfunction in PE are unclear. Therefore, we applied Normal pregnant Sprague-Dawley (SD) rats, treated with lipopolysaccharide (LPS), to establish a PE-like rat model. The hematoxylin-eosin (HE) staining method and immunohistochemistry (IHC) technology were used to detect morphological features of the placenta. IHC and Western blot were applied to examine Bax and Bcl-2 expression levels. The concentrations of serum soluble fms-like tyrosine kinase-1 (sFlt1) and placental growth factor (PIGF) were assessed by enzyme-linked immunosorbent assay (ELISA) kit. In addition, the apoptosis rates of JEG-3 and HTR-8/SVneo trophoblast cells were determined by Annexin V-FITC/PI apoptosis detection kit. Cell migratory capacities were assessed by scratch-wound assay, and RNA-sequencing assay was used to determine the mechanism of ghrelin in regulating trophoblast apoptosis. It has been found that ghrelin significantly reduced blood pressure, urinary protein, and urine creatinine in rats with PE, at the meanwhile, ameliorated placental and fetal injuries. Second, ghrelin clearly inhibited placental Bax expression and circulating sFlt-1 as well as elevated placental Bcl-2 expression and circulating PIGF, restored apoptosis and invasion deficiency of trophoblast cells caused by LPS in vitro. Finally, transcriptomics indicated that nuclear factor kappa B (NF-κB) was the potential downstream pathway of ghrelin. Our findings illustrated that ghrelin supplementation significantly improved LPS-induced PE-like symptoms and adverse pregnancy outcomes in rats by alleviating placental apoptosis and promoting trophoblast migration.

Impact of Increased Activated Protein-C Resistance, Decreased Antithrombin III Activity and Hypocomplementemia on the Gestational Outcomes of Pregnancies with MTHFR Polymorphisms

OBJECTIVE

To evaluate the impact of increased Activated Protein C (APC) resistance, decreased antithrombin III activity and hypocomplementemia on the pregnancy outcomes of the patients with methylentetrahydrofolate reductase (MTHFR) polymorphisms.

METHODS

This study was composed of 83 pregnancies with MTHFR polymorphisms. Increased APC resistance, decreased antithrombin III activity and hypocomplementemia were accepted as risk factors for poor gestational outcome.

RESULTS

Having at least one risk factor resulted in significantly higher rates of "APGAR score of<7" at the first ten minutes (p=0.009). Composite adverse outcome rate was also higher in patients with at least one of the defined risk factors despite lack of statistical significance (p=0.241). Rate of newborn with an "APGAR score of<7" at first ten minutes was significantly higher at patients with hypocomplementemia (p=0.03).

CONCLUSION

Hypocomplementemia is a risk factor for poor gestational outcome in pregnancies with MTHFR polymorphisms.

No association of a Vascular endothelial growth factor A (VEGFA) gene polymorphism with pre-eclampsia among pregnant women in Uganda

BACKGROUND

Vascular endothelial growth factor A (VEGFA) is a major angiogenic factor that plays an important role in the formation of blood vessels during embryonic development. VEGFA has been implicated in the pathophysiology of pre-eclampsia (PE), since pre-eclamptic women present with reduced levels of free circulating VEGFA. The 3' untranslated region (3'-UTR) of the VEGFA gene consists of elements that regulate the transcription and hence expression of the VEGFA protein in circulation. Hence it is suggested that variations thereof could underlie the reduced VEGFA levels observed in pre-eclamptic women. The purpose of this study was to investigate presence of the + 936C/T polymorphism, a common single nucleotide polymorphism (SNP) in the 3'-UTR of the VEGFA gene, and determine its association with PE among pregnant women in Uganda.

RESULTS

There was no significant difference observed in the allele and genotype frequencies of the + 936C/T 3' UTR-VEGFA polymorphism between pre-eclamptic and normotensive pregnant women (P > 0.05). Additionally, there was no significant difference in the median plasma levels of free VEGFA among women with the wild type, CT and TT genotypes of the + 936C/T VEGFA polymorphism (median = 0.84 pg/mL (IQR = 0.39-1.41) Vs 1.05 (0.61-1.18) Vs 1.05 (1.05-1.05) respectively, p-value = 0.7161).

CONCLUSIONS

These study findings indicate that the + 936C/T 3' UTR-VEGFA polymorphism had no significant association with increased susceptibility to PE among women in Uganda. Further studies with a larger sample size are recommended.

Worsened Stroke Outcome in a Model of Preeclampsia is Associated With Poor Collateral Flow and Oxidative Stress

BACKGROUND

Preeclampsia increases the incidence of maternal stroke, a devastating condition that is on the rise. We investigated stroke outcome in a model of experimental preeclampsia with and without treatment with clinically relevant doses of magnesium sulfate (experimental preeclampsia+MgSO4) compared to normal late-pregnant and nonpregnant rats.

METHODS

Transient middle cerebral artery occlusion was used to induce focal stroke for either 1.5 or 3 hours. Infarct volume and hemorrhagic transformation were determined as measures of stroke outcome. Changes in core middle cerebral artery and collateral flow were measured by dual laser Doppler. The relationship between middle cerebral artery perfusion deficit and infarction was used as a measure of ischemic tolerance. Oxidative stress and endothelial dysfunction were measured by 3-nitrotyrosine and 8-isoprostane, in brain and serum, respectively.

RESULTS

Late-pregnant animals had robust collateral flow and greater ischemic tolerance of brain tissue, whereas experimental preeclampsia had greater infarction that was related to poor collateral flow, endothelial dysfunction, and oxidative stress. Importantly, pregnancy appeared preventative of hemorrhagic transformation as it occurred only in nonpregnant animals. MgSO4 did not provide benefit to experimental preeclampsia animals for infarction.

CONCLUSIONS

Stroke outcome was worse in a model of preeclampsia. As preeclampsia increases the risk of future stroke and cardiovascular disease, it is worth understanding the influence of preeclampsia on the material brain and factors that might potentiate injury both during the index pregnancy and years postpartum.

The Role of Cluster C19MC in Pre-Eclampsia Development

Pre-eclampsia is a placenta-related complication occurring in 2-10% of all pregnancies. miRNAs are a group of non-coding RNAs regulating gene expression. There is evidence that C19MC miRNAs are involved in the development of the placenta. Deregulation of chromosome 19 microRNA cluster (C19MC) miRNAs expression leads to impaired cell differentiation, abnormal trophoblast invasion and pathological angiogenesis, which can lead to the development of pre-eclampsia. Information was obtained through a review of articles available in PubMed Medline. Articles on the role of the C19MC miRNA in the development of pre-eclampsia published in 2009-2022 were analyzed. This review article summarizes the current data on the role of the C19MC miRNA in the development of pre-eclampsia. They indicate a significant increase in the expression of most C19MC miRNAs in placental tissue and a high level of circulating fractions in serum and plasma, both in the first and/or third trimester in women with PE. Only for miR-525-5p, low levels of plasma expression were noted in the first trimester, and in the placenta in the third trimester. The search for molecular factors indicating the development of pre-eclampsia before the onset of clinical symptoms seems to be a promising diagnostic route. Identifying women at risk of developing pre-eclampsia at the pre-symptomatic stage would avoid serious complications in both mothers and fetuses. We believe that miRNAs belonging to cluster C19MC could be promising biomarkers of pre-eclampsia development.

An observational study of pro- and anti-angiogenic factors in hypertensive disorders of pregnancy in women of African ancestry

Hypertensive disorders in pregnancy (HDPs) are the leading cause of maternal and perinatal deaths worldwide. Despite the widely reported multisystemic pathophysiology of pre-eclampsia and other HDPs, it is unknown whether these disorders represent a continuum or separate entities making clinical diagnosis a challenge. This study aimed to investigate angiogenic, metabolic and immunoregulatory specific profiles of hypertensive and gestationally matched normotensive pregnancies. A total of 200 pregnancies from a regional hospital in South Africa, via convenience sampling, were quantitatively analysed for circulating sFlt-1; PlGF; VEGF; sENG; PAPP-A; PP13; ADAMTS 12; TGF-β1 in maternal serum samples using ELISA technique. Serum protein markers TGF-β1, sENG and PAPP-A were significantly increased (p < .05) in early-onset pre-eclampsia vs. NG1 groups. sFlt-1 was significantly higher in late-onset pre-eclampsia vs NG2 groups. The GH group showed a significant increase in TGF-β1 and PAPP-A vs. NG1 counterpart. ADAMTS12 and sENG were significantly lower in gestational hypertension vs. early-onset pre-eclampsia. No significant differences were seen in PlGF, VEGF and PP13 levels across the groups. These changes show the HDP spectrum has distinct characteristics on the angiogenic profile. Based on these results, further validation of diagnostic and prognostic biomarkers of pre-eclampsia and gestational hypertension is warranted.Impact statementWhat is already known on this subject? Hypertensive pregnancy disorders are a public health problem with adverse effects on both mother and neonate. The elusive pathogenesis of this syndrome combined with the late prevalence of symptoms leaves clinicians with a myriad of theories and indefinite treatments. The investigation into conventional anti-/angiogenic factors has been extensively studied in pre-eclampsia patients only. The overlapping clinical presentation of pre-eclampsia and gestational hypertension further complicates the diagnosis of disorders.What do the results of this study add? The investigation of novel angiogenic, metabolic and inflammatory markers will firstly contribute to generating a database for researchers both nationally and internationally. This combinatory triad of markers will assist in elucidating and differentiating between early- and late-onset preeclampsia versus gestational hypertension. The results of our cohort study suggest possible early diagnostic markers for pre-eclampsia and gestational hypertension.What are the implications of these findings for clinical practice and/or further research? Research in this area will contribute to an improvement in early disease management which will ultimately lead to a reduction in health care costs and mortality rate locally and globally. It will also enforce diagnostic and prognostic markers for hypertensive pregnancy diseases and warrant further investigation into the proteins primarily involved in the trophoblastic invasion. This will then clarify whether these two closely related hypertensive disorders represent a continuum or two separate entities.

Oxidative stress, lipid peroxidation and premature placental senescence in preeclampsia

Accelerated placental senescence is associated with preeclampsia (PE) and other pregnancy complications. It is characterized by an accelerated decline in placental function due to the accumulation of senescence patterns such as telomere shortening, mitochondrial dysfunction, oxidative damages, increased expression of phosphorylated (serine-139) histone γ-H2AX, a sensitive marker of double-stranded DNA breaks, accumulation of cross-linked ubiquitinated proteins and sirtuin inhibition. Among the lipid oxidation products generated by the peroxidation of polyunsaturated fatty acids, aldehydes such as acrolein, 4-hydroxy-2-nonenal, 4-oxo-2-nonenal, are present in the blood and placenta from PE-affected women and could contribute to PE pathogenesis and accelerated placental aging. In this review we summarize the current knowledge on premature placental senescence and the role of oxidative stress and lipid oxidation-derived aldehydes in this process, as well as their links with PE pathogenesis. The interest of developing (or not) new therapeutic strategies targeting lipid peroxidation is discussed, the objective being a better understanding of accelerated placental aging in PE pathophysiology, and the prevention of PE bad outcomes.

Pathological Role of Reactive Oxygen Species on Female Reproduction

Oxidative stress (OS), a clinical predicament characterized by a shift in homeostatic imbalance among prooxidant molecules embracing reactive oxygen species (ROS) and reactive nitrogen species (RNS), along with antioxidant defenses, has been established to play an indispensable part in the pathophysiology of subfertility in both human males and females. ROS are highly reactive oxidizing by-products generated during critical oxygen-consuming processes or aerobic metabolism. A healthy body system has its own course of action to maintain the equilibrium between prooxidants and antioxidants with an efficient defense system to fight against ROS. But when ROS production crosses its threshold, the disturbance in homeostatic balance results in OS. Besides their noxious effects, literature studies have depicted that controlled and adequate ROS concentrations exert physiologic functions, especially that gynecologic OS is an important mediator of conception in females. Yet the impact of ROS on oocytes and reproductive functions still needs a strong attestation for further analysis because the disruption in prooxidant and antioxidant balance leads to abrupt ROS generation initiating multiple reproductive diseases such as polycystic ovary syndrome (PCOS), endometriosis, and unexplained infertility in addition to other impediments in pregnancy such as recurrent pregnancy loss, spontaneous abortion, and preeclampsia. The current article elucidates the skeptical state of affairs created by ROS that influences female fertility.

Extracellular Vesicles From Women With Severe Preeclampsia Impair Vascular Endothelial Function

BACKGROUND

Preeclampsia (PE) manifesting as hypertension and organ injury is mediated by vascular dysfunction. In biological fluids, extracellular vesicles (EVs) containing microRNA (miRNA), protein, and other cargo released from the placenta may serve as carriers to propagate injury, altering the functional phenotype of endothelial cells. PE has been consistently correlated with increased levels of placenta-derived EVs (pEVs) in maternal circulation. However, whether pEVs impaired endothelial cell function remains to be determined. In this study, we hypothesize that pEVs from pregnant women with severe PE (sPE) impair endothelial function through altered cell signaling.

METHODS

We obtained plasma samples from women with sPE (n = 14) and normotensive pregnant women (n = 15) for the isolation of EVs. The total number of EV and pEV contribution was determined by quantifying immunoreactive EV-cluster of designation 63 (CD63) and placental alkaline phosphatase (PLAP) as placenta-specific markers, respectively. Vascular endothelial functional assays were determined by cell migration, electric cell-substrate impedance sensing in human aortic endothelial cells (HAECs), and wire myography in isolated blood vessels, preincubated with EVs from normotensive and sPE women.

RESULTS

Plasma EV and pEV levels were increased in sPE when compared to normotensive without a significant size distribution difference in sPE (108.8 ± 30.2 nm) and normotensive-EVs (101.3 ± 20.3 nm). Impaired endothelial repair and proliferation, reduced endothelial barrier function, reduced endothelial-dependent vasorelaxation, and decreased nitrite level indicate that sPE-EVs induced vascular endothelial dysfunction. Moreover, sPE-EVs significantly downregulated endothelial nitric oxide synthase (eNOS and p-eNOS) when compared to normotensive-EV.

CONCLUSIONS

EVs from sPE women impair endothelial-dependent vascular functions in vitro.

Exosomal mRNA and lncRNA profiles in cord blood of preeclampsia patients

BACKGROUND

Exosomes are endosome-derived membrane vesicles that contain numerous RNAs and allow intercellular communication. The roles of mRNAs and lncRNAs from umbilical cord blood exosomes in the development of preeclampsia (PE) remain unclear.

METHODS

In the study, microarray technology was used to construct the differential mRNA and lncRNA expression profiles in umbilical cord blood exosomes between PE patients and normal controls.

RESULTS

Totally, 120 differentially expressed mRNAs and 248 differentially expressed lncRNAs were identified. Pathway analysis showed that the differentially expressed mRNAs were related to glycolysis/gluconeogenesis, PI3K-Akt signaling pathway and JAK-STAT signaling pathway, which are critical in PE development. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted for the differential lncRNA-associated mRNAs. We found several significantly enriched pathways were closely associated with metabolic process, cell proliferation, differentiation, and apoptosis. Moreover, the constructed pathway network revealed key pathways in PE, including apoptosis and TGF-beta signaling pathway. Further analysis of lncRNA/miRNA interactions showed that most of the lncRNAs had miRNA binding sites, and some of them were associated with PE.

CONCLUSIONS

The study highlights the importance of exosomal mRNAs and lncRNAs in umbilical cord blood, and provides new insight into the development of PE.

Assessment of Placental Extracellular Vesicles-Associated Fas Ligand and TNF-Related Apoptosis-Inducing Ligand in Pregnancies Complicated by Early and Late Onset Preeclampsia

Preeclampsia (PE) is a hypertensive disorder that affects 2-8% of pregnancies and is one of the main causes of fetal, neonatal, and maternal mortality and morbidity worldwide. Although PE etiology and pathophysiology remain unknown, there is evidence that the hyperactivation of maternal immunity cells against placental cells triggers trophoblast cell apoptosis and death. It has also been reported that placenta-derived extracellular vesicles (EV) carry Fas ligand (FasL) and Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and trigger apoptosis in Jurkat T cells. This study aimed to quantify and compare FasL and TRAIL expression in EV derived from cultures of placenta explants from women with PE (early versus late) and women with uncomplicated pregnancies. Also, the study assessed EV capacity to induce apoptosis in Jurkat T cells. The authors isolated EV from placenta explant cultures, quantified FasL and TRAIL using ELISA, and analyzed EV apoptosis-inducing capability by flow cytometry. Results showed increased FasL and TRAIL in EV derived from placenta of women with PE, and increased EV apoptosis-inducing capability in Jurkat T cells. These results offer supporting evidence that EV FasL and TRAIL play a role in the pathophysiology of PE.

Hypoxia-Induced Alpha-Globin Expression in Syncytiotrophoblasts Mimics the Pattern Observed in Preeclamptic Placentas

Preeclampsia (PE) is a pregnancy disorder associated with placental dysfunction and elevated fetal hemoglobin (HbF). Early in pregnancy the placenta harbors hematopoietic stem and progenitor cells (HSPCs) and is an extramedullary source of erythropoiesis. However, globin expression is not unique to erythroid cells and can be triggered by hypoxia. To investigate the role of the placenta in increasing globin levels previously reported in PE, flow cytometry, histological and immunostaining and in situ analyses were used on placenta samples and ex vivo explant cultures. Our results indicated that in PE pregnancies, placental HSPC homing and erythropoiesis were not affected. Non-erythroid alpha-globin mRNA and protein, but not gamma-globin, were detected in syncytiotrophoblasts and stroma of PE placenta samples. Similarly, alpha-globin protein and mRNA were upregulated in normal placenta explants cultured in hypoxia. The upregulation was independent of HIF1 and NRF2, the two main candidates of globin transcription in non-erythroid cells. Our study is the first to demonstrate alpha-globin mRNA expression in syncytiotrophoblasts in PE, induced by hypoxia. However, gamma-globin was only expressed in erythrocytes. We conclude that alpha-globin, but not HbF, is expressed in placental syncytiotrophoblasts in PE and may contribute to the pathology of the disease.

CREB-binding protein (CREBBP) and preeclampsia: a new promising target gene

Preeclampsia (PE) is a major complication of pregnancy and remains a leading cause of neonatal and maternal mortality worldwide. Several studies have revealed that the incidence of preeclampsia is high in mothers who carried a fetus with Rubinstein-Taybi Syndrome due to the mutation in CREBBP. We aimed to compare the expression level of the CERBBP gene between preeclamptic and healthy placenta in our study. The expression level of CREBBP gene was evaluated in a total of one hundred placental biopsies from PE patients and healthy pregnant women after delivery using quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, the differential expression of CREBBP was assessed between the maternal and fetal sides of the placenta. Expression of the CREBBP gene was higher in preeclampsia patients compared with the controls (Fold change = 2.158; P = 0.018). Moreover, the gene expression was slightly higher in the fetal side of the placenta, although it was not significantly different (Fold change = 1.713, P = 0.254). Our findings show a role for CREBBP in the pathogenesis of PE. Due to the important role of CREBBP in angiogenesis and hypoxia, the gene may serve as a promising target in future studies.

Role of oxidative stress in the dysfunction of the placental endothelial nitric oxide synthase in preeclampsia

Preeclampsia (PE) is a multifactorial pregnancy disease, characterized by new-onset gestational hypertension with (or without) proteinuria or end-organ failure, exclusively observed in humans. It is a leading cause of maternal morbidity affecting 3–7% of pregnant women worldwide. PE pathophysiology could result from abnormal placentation due to a defective trophoblastic invasion and an impaired remodeling of uterine spiral arteries, leading to a poor adaptation of utero-placental circulation. This would be associated with hypoxia/reoxygenation phenomena, oxygen gradient fluctuations, altered antioxidant capacity, oxidative stress, and reduced nitric oxide (NO) bioavailability. This results in part from the reaction of NO with the radical anion superoxide (O₂^•−), which produces peroxynitrite ONOO^-, a powerful pro-oxidant and inflammatory agent. Another mechanism is the progressive inhibition of the placental endothelial nitric oxide synthase (eNOS) by oxidative stress, which results in eNOS uncoupling via several events such as a depletion of the eNOS substrate L-arginine due to increased arginase activity, an oxidation of the eNOS cofactor tetrahydrobiopterin (BH4), or eNOS post-translational modifications (for instance by S-glutathionylation). The uncoupling of eNOS triggers a switch of its activity from a NO-producing enzyme to a NADPH oxidase-like system generating O₂^•−, thereby potentiating ROS production and oxidative stress. Moreover, in PE placentas, eNOS could be post-translationally modified by lipid peroxidation-derived aldehydes such as 4-oxononenal (ONE) a highly bioreactive agent, able to inhibit eNOS activity and NO production. This review summarizes the dysfunction of placental eNOS evoked by oxidative stress and lipid peroxidation products, and the potential consequences on PE pathogenesis.

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Physiological ROS production is enhanced during pregnancy.

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eNOS is one of the main target of oxidative stress in PE placenta.

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eNOS is S-glutathionylated in PE placentas.

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eNOS is modified by lipid oxidation products in PE placentas.

The association between first trimester placental biomarkers and placental lesions of maternal vascular malperfusion

INTRODUCTION

Abnormal levels of first trimester placental biomarkers are associated with the development of placental syndrome (PS). However, prediction performance is moderate, possibly explained by the clinical heterogeneity of PS. Aim of this study is to investigate the association between first trimester biomarkers and the presence of maternal vascular malperfusion (MVM), as a marker for placental insufficiency.

METHODS

This retrospective study included 195 women with available first trimester blood sample and placenta histological sections for examination at the Maastricht University Medical Centre. Women were divided into 4 groups, based on the presence of having MVM lesions and/or PS. Levels of PAPP-A, PlGF and sFlt-1 were measured and MVM lesions were classified according to the Amsterdam Placental Workshop Group Consensus Statement.

RESULTS

MVM occurrence was observed in 32% of the uncomplicated pregnancies. Women with MVM (regardless of the PS) had lower levels of PAPP-A (p = 0.038) and sFLt-1 (p = 0.006), and a non-significant trend for lower PlGF and sFlt-1/PlGF ratio compared to women without MVM. Low PAPP-A levels individually and in combination with the presence of PS was significantly associated with MVM lesions (aOR = 3.0 and 6.1, respectively), as did the combination of low PlGF levels and PS (aOR = 4.6). In women with PS, having MVM increased the incidence of fetal growth restriction, small for gestational age neonates, lower birthweight and adverse neonatal outcome.

DISCUSSION

Our findings suggest that MVM lesions were found to be associated with increased obstetric risks due to early placental dysfunction that can potentially be predicted by the use of first trimester biomarkers.

microRNA-646 inhibits angiogenesis of endothelial progenitor cells in pre-eclamptic pregnancy by targeting the VEGF-A/HIF-1α axis

Pre-eclampsia is a complication that occurs during pregnancy, the pathological feature of which is a change in vascular endothelial homeostasis. microRNA (miR)-646 is an anti-angiogenic miRNA that has been indicated to exhibit potential anti-angiogenic effects in endothelial cells cultured in vitro and in ischemia-induced angiogenesis. However, whether miR-646 has therapeutic potential in placental angiogenesis in pre-eclampsia remains to be determined. In the current study, human peripheral blood-derived endothelial progenitor cells (EPCs) were isolated to study the coordination between miR-646, vascular endothelial growth factor (VEGF)-A and hypoxia-inducible factor (HIF)-1α expression in preeclampsia EPCs. EPCs were isolated from human peripheral blood to demonstrate a potential interaction between miR-646 and targets (VEGF-A) in vitro. The number of EPCs and the expression of miR-646 in patients with preeclampsia was detected, and the effects of miR-646 on EPC function and preeclampsia angiogenesis was assessed. Clinical specimens demonstrated that miR-646 expression was enhanced in pregnancy with preeclampsia. The results indicated that miR-646 suppressed EPCs multiplication, differentiation and migration. miR-646 was observed to exert an anti-angiogenic function by suppressing the expression of angiogenic cytokines VEGF-A and HIF-1α. Additionally, luciferase results displayed that miR-646 downregulated VEGF-A expression by directly binding to a specific sequence in its 3'-untranslated region. The results of the current study demonstrated that the miR-646/VEGF-A/HIF-1α axis is significant for angiogenic properties of EPCs in vitro and in vivo placental vasculogenesis. The results of the present study provide a new insight into microRNA regulation of vessel homeostasis and angiogenesis, and a basis for alternative treatments for patients with pre-eclampsia.

Transfection of maternal cells with placental extracellular vesicles in preeclampsia

The role of extracellular vesicles is widely studied. As well as other organs, placenta produces extracellular vesicles during both, normal and pathological pregnancies. During pregnancy, placental/fetal free DNA circulates in maternal blood. Concentrations of free placental DNA are much higher when pregnancy complications of various etiologies occur. Such a complication could be preeclampsia. In our previous animal model, administration of pure DNA isolated from fetus did not induce any prenatal complications. Here we hypothesize that in real life during preeclampsia or other pregnancy complications, placental DNA might be transported by extracellular vesicles to maternal cells. Also, our preliminary data prove that placental DNA is present in circulating exosomes in maternal blood. Therefore, a lipid bilayer of extracellular vesicles could protect DNA from degradation by enzymes. Extracellular vesicles tend to merge with other cells, therefore, following expression of fetal genes from placental extracellular vesicles in maternal cells could lead to an immune response already observed in pregnancy complications. Future studies should be mainly focused on verification of our hypothesis and evaluate the potential of placental/fetal extracellular vesicles and their gene transfer in preeclampsia or other pregnancy complications.

Mechanisms of Endothelial Dysfunction in Pre-eclampsia and Gestational Diabetes Mellitus: Windows Into Future Cardiometabolic Health?

Placental insufficiency and adipose tissue dysregulation are postulated to play key roles in the pathophysiology of both pre-eclampsia (PE) and gestational diabetes mellitus (GDM). A dysfunctional release of deleterious signaling motifs can offset an increase in circulating oxidative stressors, pro-inflammatory factors and various cytokines. It has been previously postulated that endothelial dysfunction, instigated by signaling from endocrine organs such as the placenta and adipose tissue, may be a key mediator of the vasculopathy that is evident in both adverse obstetric complications. These signaling pathways also have significant effects on long term maternal cardiometabolic health outcomes, specifically cardiovascular disease, hypertension, and type II diabetes. Recent studies have noted that both PE and GDM are strongly associated with lower maternal flow-mediated dilation, however the exact pathways which link endothelial dysfunction to clinical outcomes in these complications remains in question. The current diagnostic regimen for both PE and GDM lacks specificity and consistency in relation to clinical guidelines. Furthermore, current therapeutic options rely largely on clinical symptom control such as antihypertensives and insulin therapy, rather than that of early intervention or prophylaxis. A better understanding of the pathogenic origin of these obstetric complications will allow for more targeted therapeutic interventions. In this review we will explore the complex signaling relationship between the placenta and adipose tissue in PE and GDM and investigate how these intricate pathways affect maternal endothelial function and, hence, play a role in acute pathophysiology and the development of future chronic maternal health outcomes.

The effects of placental long noncoding RNA H19 polymorphisms and promoter methylation on H19 expression in association with preeclampsia susceptibility

The effect of DNA methylation on gene expression triggered it as a susceptibility factor in various diseases including preeclampsia (PE). The pathogenesis of PE is closely associated with the methylation status and genetic variants of relevant genes. Therefore, the aim of the study was to investigate the possible impacts of the placental DNA methylation and rs3741219, rs217727, and rs2107425 polymorphisms of the H19 gene on the PE susceptibility as well as the its mRNA expression. Moreover, eight haplotypes of three loci in the H19 gene were analyzed. In this case-control study, the placentas of 107 preeclamptic and 113 non-preeclamptic women were collected after delivery. The methylation status was assessed by methylation-specific polymerase chain reaction (PCR). The H19 polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism or amplification refractory mutation system-polymerase chain reaction methods. The quantitative real time PCR was used for mRNA expression assay. The placental H19 rs3741219 and rs2107425 polymorphisms were not associated with PE. However, H19 rs217727CT and TT genotypes might be associated with a 9.2- and 17.7-fold increased risk of PE, respectively. The T_rs3741219 C_rs217727 C_rs2107425 and T_rs3741219 C_rs217727 T_rs2107425 haplotypes were significantly lower, whereas the T_rs3741219 T_rs217727 C_rs2107425 and C_rs3741219 T_rs217727 C_rs2107425 haplotypes were significantly higher in PE women. Promoter but not upstream region hypermethylation of H19 gene could be led to decreased risk of PE (MM vs. UM + UU). No significant difference was observed in the placental mRNA expression between two groups. The H19 expression was significantly higher in women with unmethylated (UU), compared to methylated promoter (MM). The H19 expression was 17- and 15-fold higher in H19-rs2107425 CC and CT genotypes in PE women. In conclusion, the H19 rs2107425 polymorphism was associated with a higher risk of PE and increased H19 mRNA expression. The promoter hypermethylation of H19 gene was associated with a lower risk of PE and decreased H19 mRNA expression.

Placental Syncytiotrophoblast-Derived Extracellular Vesicles Carry Active NEP (Neprilysin) and Are Increased in Preeclampsia

NEP (neprilysin) is a widely expressed membrane-bound metalloprotease, which binds and cleaves a variety of peptides including vasodilators, natriuretics, and diuretics. Higher levels of NEP result in hypertension-a cardinal feature of the placental disease preeclampsia. Syncytiotrophoblast-derived extracellular vesicles (EVs), comprising microvesicles and exosomes, are released into the peripheral circulation in pregnancy and are postulated as a key mechanism coupling placental dysfunction and maternal phenotype in preeclampsia. We aimed to determine whether higher levels of active NEP are found in syncytiotrophoblast-derived EVs in preeclampsia compared with normal pregnancy. Using immunostaining and Western blotting, we first demonstrated that NEP levels are greater not only in preeclampsia placental tissue but also in syncytiotrophoblast-derived microvesicles and exosomes isolated from preeclampsia placentas ( P<0.05, n=5). We confirmed placental origin using antibody-coated magnetic beads to isolate NEP-bound vesicles, finding that they stain for placental alkaline phosphatase. NEP on syncytiotrophoblast-derived EVs is active and inhibited by thiorphan ( P<0.01, n=3; specific inhibitor). Syncytiotrophoblast-derived microvesicles, isolated from peripheral plasma, demonstrated higher NEP expression in preeclampsia using flow cytometry ( P<0.05, n=8). We isolated plasma exosomes using size-exclusion chromatography and showed greater NEP activity in preeclampsia ( P<0.05, n=8). These findings show that the placenta releases active NEP into the maternal circulation on syncytiotrophoblast-derived EVs, at significantly greater levels in preeclampsia. NEP has pathological roles in hypertension, heart failure, and amyloid deposition, all of which are features of preeclampsia. Circulating syncytiotrophoblast-derived EV-bound NEP thus may contribute to the pathogenesis of this disease.

PFOS Modulates Interactive Epigenetic Regulation in First-Trimester Human Trophoblast Cell Line HTR-8/SVneo

Organic compounds have been linked to adverse pregnancy complications. Perfluorooctanesulfonic acid (PFOS), a man-made fluorosurfactant and global pollutant, has been shown to induce oxidative stress in various cell types. Oxidative stress plays a key role in leading several placental diseases including preeclampsia (PE), gestational diabetes, spontaneous abortion, preterm labor, and intrauterine growth restriction. Recently, epigenetic regulation such as histone modifications, DNA methylation, and microRNAs (miRNAs), are shown to be associated with oxidative stress as well as pregnancy complications such as PE. However, whether PFOS exerts its detrimental effects in the placenta through epigenetics remains to be unveiled. Therefore, we aimed to investigate the effect of PFOS-induced reactive oxygen species (ROS) generation in first trimester human trophoblast cell line (HTR-8/SV_neo) and whether epigenetic regulation is involved in this process. When treated with a range of PFOS doses at 24 and 48 h, even at 10 μM, it significantly increased the ROS production and decreased gene and protein expression, respectively, of the DNA methyltransferases DNMT1 (p < 0.001; p < 0.05), DNMT3A (p < 0.001; p < 0.05), and DNMT3B (p < 0.01; p < 0.01) and the sirtuins, for example, SIRT1 (p < 0.001; p < 0.001) and SIRT3 (p < 0.001; p < 0.05), while reducing global DNA methylation (p < 0.01) and increasing protein lysine acetylation (p < 0.001) as compared to vehicle controls. Interestingly, PFOS (10 μM) significantly increased miR29-b (p < 0.01), which has been previously reported to be associated with PE. The observed epigenetic effects were shown to be dependent on the expression of miR-29b, as knockdown of miR-29b significantly alters the gene and protein expression of DNMT1, DNMT3A, DNMT3B, SIRT1, and SIRT3 and ROS production as well as global DNA methylation and protein acetylation. This study provides for the first time a novel insight into PFOS-induced ROS generation via regulation of sets of the interactive epigenetic circuit in the placenta, which may lead to pregnancy complications.

Status of VEGF in preeclampsia and its effect on endoplasmic reticulum stress in placental trophoblast cells

Objective

To explore the role of VEGF in attenuating endoplasmic reticulum stress in placental trophoblast cells.

Study design

Study was divided into following parts: 1. Serum Analysis of GRP78 and VEGF using sandwich ELISA. 2. Expression of VEGF and GRP78 in placentae by immunohistochemistry (IHC). 3. In Vitro experiments. Status of ER stress markers (GRP78, eIF2α, XBP1, ATF6 and CHOP) was assessed at various time points (8 h, 14 h, 24 h) when trophoblast cells were treated with varying concentration(s) of VEGF and also by adding recombinant VEGF at protein (Immunofluorescence, Western blot) and transcript levels (qRT-PCR).

Results

Increased GRP78 and decreased VEGF protein levels in sera and placentae of preeclamptic pregnant women and reduced expression of various ER stress markers at both transcript and protein levels was observed in trophoblast cells when they were exposed to recombinant VEGF thereby indicating positive role of VEGF in alleviating ER stress.

Conclusions

Reduced expression of ER stress markers in trophoblast cells against increased VEGF highlighted a new window to explore prospective drugs that can be designed to modulate the activities of various ER stress sensors in order to alleviate ER stress in pregnant women with preeclampsia.

Preeclampsia is Associated with Sex-Specific Transcriptional and Proteomic Changes in Fetal Erythroid Cells

Preeclampsia (PE) has been associated with placental dysfunction, resulting in fetal hypoxia, accelerated erythropoiesis, and increased erythroblast count in the umbilical cord blood (UCB). Although the detailed effects remain unknown, placental dysfunction can also cause inflammation, nutritional, and oxidative stress in the fetus that can affect erythropoiesis. Here, we compared the expression of surface adhesion molecules and the erythroid differentiation capacity of UCB hematopoietic stem/progenitor cells (HSPCs), UCB erythroid profiles along with the transcriptome and proteome of these cells between male and female fetuses from PE and normotensive pregnancies. While no significant differences were observed in UCB HSPC migration/homing and in vitro erythroid colony differentiation, the UCB HSPC transcriptome and the proteomic profile of the in vitro differentiated erythroid cells differed between PE vs. normotensive samples. Accordingly, despite the absence of significant differences in the UCB erythroid populations in male or female fetuses from PE or normotensive pregnancies, transcriptional changes were observed during erythropoiesis, particularly affecting male fetuses. Pathway analysis suggested deregulation in the mammalian target of rapamycin complex 1/AMP-activated protein kinase (mTORC1/AMPK) signaling pathways controlling cell cycle, differentiation, and protein synthesis. These results associate PE with transcriptional and proteomic changes in fetal HSPCs and erythroid cells that may underlie the higher erythroblast count in the UCB in PE.

Cell-Free DNA (cfDNA) Fetal Fraction in Early- and Late-Onset Fetal Growth Restriction

OBJECTIVE

Our objective was to retrospectively evaluate whether the levels of cell-free DNA (cfDNA) fetal fraction differed in the first trimester of pregnancies between controls and those who subsequently developed early- or late-onset fetal growth restriction (FGR).

METHODS

This was a case-control study conducted between May 2015 and May 2018 in 231 low-risk women who had received first trimester screening for major fetal aneuploidies (Panorama, Natera, San Carlos, CA, USA). Early- and late-onset FGR developed in 5 and 16 women, respectively, according to Delphi criteria. Multiples of median (MoM) were used to evaluate the differences in cfDNA fetal fraction between cases and controls. cfDNA fetal fraction was adjusted for gestational age (from 10 + 0 to 13 + 6 gestational weeks) and maternal weight (43-96 kg).

RESULTS

The median cfDNA fetal fractions for controls and early- and late-onset FGR were 1.00 (interquartile range [IQR] 0.89-1.12), 0.69 (IQR 0.44-0.84) and 0.93 (IQR 0.83-1.03) MoM, respectively. Statistically lower cfDNA fetal fraction MoM values were observed only in patients with early-onset FGR (Kruskal-Wallis test with Dunn post hoc test). In a 1:35 ratio (one case of early-onset FGR: 35 controls), the mean observed rank of 2.00 ± 2.23 in the cases was significantly lower than the expected 18.97 ± 10.17 (p < 0.001).

CONCLUSIONS

Low-risk pregnancies that developed early-onset FGR had lower cfDNA fetal fractions than did the matched controls. This result is consistent with the placental dysfunction typical of early-onset FGR. For possible clinical use, the cfDNA fetal fraction would yield a better predictive value if adjusted for maternal weight, since maternal weight affects both cfDNA fetal fraction and the occurrence of FGR.

Preeclamptic placentae release factors that damage neurons: implications for foetal programming of disease

Prenatal development is a critical period for programming of neurological disease. Preeclampsia, a pregnancy complication involving oxidative stress in the placenta, has been associated with long-term health implications for the child, including an increased risk of developing schizophrenia and autism spectrum disorders in later life. To investigate if molecules released by the placenta may be important mediators in foetal programming of the brain, we analysed if placental tissue delivered from patients with preeclampsia secreted molecules that could affect cortical cells in culture. Application of culture medium conditioned by preeclamptic placentae to mixed cortical cultures caused changes in neurons and astrocytes that were related to key changes observed in brains of patients with schizophrenia and autism, including effects on dendrite lengths, astrocyte number as well as on levels of glutamate and γ-aminobutyric acid receptors. Treatment of the placental explants with an antioxidant prevented neuronal abnormalities. Furthermore, we identified that bidirectional communication between neurons and astrocytes, potentially via glutamate, is required to produce the effects of preeclamptic placenta medium on cortical cells. Analysis of possible signalling molecules in the placenta-conditioned medium showed that the secretion profile of extracellular microRNAs, small post-transcriptional regulators, was altered in preeclampsia and partially rescued by antioxidant treatment of the placental explants. Predicted targets of these differentially abundant microRNAs were linked to neurodevelopment and the placenta. The present study provides further evidence that the diseased placenta may release factors that damage cortical cells and suggests the possibility of targeted antioxidant treatment of the placenta to prevent neurodevelopmental disorders.

The direct and sustained consequences of severe placental hypoxia on vascular contractility

INTRODUCTION

Preeclampsia is a major health problem in human pregnancy, severely complicating 5-8% of all pregnancies. The emerging molecular mechanism is that conditions like hypoxic stress trigger the release of placental messengers into the maternal circulation, which causes preeclampsia. Our objective was to develop an in vitro model, which can be used to further elucidate the molecular mechanisms of preeclampsia and which might be used to find a remedy.

METHODS

Human non-complicated term placentas were collected. Placental explants were subjected to severe hypoxia and the conditioned media were added to chorionic arteries that were mounted into a myograph. Contractile responses of the conditioned media were determined, as well as effects on thromboxane-A2 (U46619) induced contractility. To identify the vasoactive compounds present in the conditioned media, specific receptor antagonists were evaluated.

RESULTS

Factors released by placental explants generated under severe hypoxia induced an increased vasoconstriction and vascular contractility to thromboxane-A2. It was found that agonists for the angiotensin-I and endothelin-1 receptor released by placental tissue under severe hypoxia provoke vasoconstriction. The dietary antioxidant quercetin could partially prevent the acute and sustained vascular effects in a concentration-dependent manner.

DISCUSSION

Both the acute vasoconstriction, as well as the increased contractility to U46619 are in line with the clinical vascular complications observed in preeclampsia. Data obtained with quercetin supports that our model opens avenues for e.g. nutritional interventions aimed at treating or preventing preeclampsia.

Pre-eclampsia affects procalcitonin production in placental tissue

PROBLEM

Procalcitonin (PCT) is the prohormone of calcitonin which is usually released from neuroendocrine cells of the thyroid gland (parafollicular) and the lungs (K cells). PCT is synthesized by almost all cell types and tissues, including monocytes and parenchymal tissue, upon LPS stimulation. To date, there is no evidence for PCT expression in the placenta both in physiological and pathological conditions.

METHOD

Circulating and placental PCT levels were analysed in pre-eclamptic (PE) and control patients. Placental cells and macrophages (PBDM), stimulated with PE sera, were analysed for PCT expression. The effect of anti-TNF-α antibody was analysed.

RESULTS

Higher PCT levels were detected in PE sera and in PE placentae compared to healthy women. PE trophoblasts showed increased PCT expression compared to those isolated from healthy placentae. PE sera induced an upregulation of PCT production in macrophages and placental cells. The treatment of PBDM with PE sera in the presence of anti-TNF-α completely abrogated the effect induced by pathologic sera.

CONCLUSION

Trophoblast cells are the main producer of PCT in PE placentae. TNF-α, in association with other circulating factors present in PE sera, upregulates PCT production in macrophages and normal placental cells, thus contributing to the observed increased in circulating PCT in PE sera.

Differential expression of miRNAs are associated with the insulin signaling pathway in preeclampsia and gestational hypertension

OBJECTIVES

The objective of this study was to determine microRNAs (miRNAs) expression levels in placental tissue and serum samples from preeclampsia (PE) and gestational hypertensive (GH) patients.

STUDY DESIGN

Using a targeted qPCR method, the selected miRNAs putatively involved in the PE and GH were examined from normotensive (n = 32), PE (n = 32) and GH (n = 28) in South African women. Western blot analysis of protein expressions of AKT and PI3K was performed in the placental tissue of all three groups.

RESULTS

qPCR results of serum miR-222 expression levels showed a significant decrease in PE compared to GH and normotensive groups. miR-29a expression levels were significantly increased in PE and GH groups compared to normotensives. Serum expression levels of miR-181a in GH showed a significant increase compared to the PE and normotensive groups. Placental tissue expression levels of miR-181a were significantly increased in PE and GH groups compared to normotensives. Western blot results of placental tissue showed a decrease in the expression levels of AKT-serine and threonine in the PE groups compared to the normotensives and a significantly higher expression in the GH groups compared to normotensives. Phosphatidyl-inositol-3 kinase (PI3K) expression levels were significantly decreased in PE and GH groups compared to normotensives.

CONCLUSION

The present study, interestingly, demonstrates the differential expression of circulating miRNA in GH and a correlation between the expression levels of miRNAs with AKT/PI3K in the insulin signaling pathway, reinforcing the presence of metabolic dysregulation in PE and GH.

Circulating fetal and total cell-free DNA, and sHLA-G in black South African women with gestational hypertension and pre-eclampsia

OBJECTIVE

Quantification of circulating fetal and total cell-free DNA (cfDNA) and soluble human leucocyte antigen (HLAG) in gestational hypertension and pre-eclampsia.

METHODS

Serum cfDNA were quantified in controls, pre-eclamptics, and gestational hypertensive patients using real-time qPCR. Soluble HLAG was measured by enzyme-linked immune-sorbent assay.

RESULTS

Serum fetal and total cfDNA levels were higher in pre-eclampsia compared with the controls and gestational hypertensives (p < 0.001), more so in severe compared with mild-to-moderate pre-eclampsia (p < 0.05). Soluble HLAG levels were lower in pre-eclamptics than controls and gestational hypertension (p < 0.05).

CONCLUSION

Circulating fetal and total cfDNA were increased, while soluble HLAG was decreased in pre-eclampsia.

Role of kidney biomarkers [Kidney injury molecule-1, Calbindin, Interleukin-18 and Monocyte chemoattractant protein-1] in HIV associated pre-eclampsia

OBJECTIVE

Both HIV infection and pre-eclampsia (PE) are associated with considerable maternal mortality in South Africa. This study was designed to compare the urinary levels of kidney injury molecule-1 (KIM-1), calbindin, interleukin-18 (IL-18), and monocyte chemoattractant protein-1 (MCP-1) in HIV associated normotensive and preeclamptic pregnancies.

METHODS

Following ethical approval and written consent, urine samples were collected from HIV negative (HIV -ve) normotensive pregnant (n = 19), HIV positive (HIV +ve) normotensive pregnant (n = 19), HIV -ve pre-eclamptic (n = 19) and HIV +ve pre-eclamptic (n = 19) women. The concentrations of KIM-1, calbindin, IL-18 and MCP-1 were assessed using the Bioplex technology.

RESULTS

In contrast to IL-18 (p > 0.05) and MCP-1 (p > 0.05), the concentrations of KIM-1 (p = 0.02) and calbindin (p = 0.02) were significantly higher in PE compared to normotensive pregnancies, irrespective of HIV status. Based on HIV status, all 4 analytes were similar between HIV+ve and HIV-ve groups. Urinary KIM-1 levels in the HIV -ve pre-eclamptics were significantly higher than those in the HIV -ve women with normal pregnancies (p = 0.007). The maternal hypertension and/or HIV profile has no marked impact on the fetal weight.

CONCLUSION

Our results demonstrate an increase in the urinary level of kidney injury molecule-1 and calbindin in PE, implicating their possible value as biomarkers of kidney injury. We observed no differences in the levels of KIM-1, IL-18, MCP-1 and calbindin based on HIV status. We propose that studies with larger sample sizes using these markers be conducted to establish their use as markers of diagnosing kidney injury in PE.

Complement component C1q as potential diagnostic but not predictive marker of preeclampsia

PROBLEM

We have previously found that C1q is constitutively expressed by invading trophoblast and endothelial cells of decidua and contributes to vascular and tissue remodeling. Based on these findings, we sought to determine whether there were changes in the circulating level of C1q that may be used as a diagnostic and predictive marker of preeclampsia.

METHOD OF STUDY

We measured the levels of C1q, C4, and complement activation products in serum or plasma of normal pregnant women and preeclamptic patients from different cohorts.

RESULTS

We observed a marked decrease in the concentration of C1q associated with a reduced level of C4 in preeclamptic patients as compared to matched healthy pregnant woman but no significant difference in the circulating level of the activating products C5a and the soluble terminal complement complex sC5b-9. Analysis of serum samples collected at early phase of pregnancy from women who later developed preeclampsia failed to show a decrease in C1q level.

CONCLUSION

The results of the present investigation demonstrate that low levels of C1q and C4 are associated with preeclampsia but cannot be used as predictive markers.

Update of syncytiotrophoblast derived extracellular vesicles in normal pregnancy and preeclampsia

The release of extracellular vesicles (EV) by the syncytiotrophoblast (STB) may be an important mechanism by which the placenta signals to the mother. STB derived EV (STBEV) are comprised predominantly of exosomes (50-150nm) and microvesicles (100-1000nm) that contain bioactive mediators such as proteins, nucleic acids and lipids. They, along with larger syncytial nuclear aggregates are released by the STB into the maternal circulation throughout gestation in normal pregnancy where they appear to have an immunoregulatory role, inhibiting T cell and NK cell responses. In pre-eclampsia (PE) STBEV are released in significantly increased numbers and have pro-inflammatory, anti-angiogenic and procoagulant activity, implicating them in the maternal systemic inflammation, endothelial dysfunction and activation of the clotting system which typifies the disorder. Research has focused on understanding the biological significance of STBEV by measuring their size and repertoire of molecules carried and how they differ in normal pregnancy and PE, using techniques such as Nanoparticle Tracking Analysis, flow cytometry and mass spectrometry. We have also found alterations in STBEV surface glycans associated with PE. The goal is to better understand the role STBEV play in normal pregnancy and PE and whether they are potential biomarkers of placental pathology and therapeutic targets in PE.

Placental exosomes and pre-eclampsia: Maternal circulating levels in normal pregnancies and, early and late onset pre-eclamptic pregnancies

INTRODUCTION AND AIM

Exosomes are a subtype of extracellular vesicle (20-130 nm) released by biological cells under normal and pathological conditions. Although there have been reports of circulating exosomes in normal pregnancy, the relevance of placental-derived exosomes in normal and abnormal pregnancies still needs to be elucidated. The aim of this study was to quantify total and placental-derived exosomes in maternal plasma from normal (N), early onset- and late onset-preeclampsia (PE).

METHOD

Plasma samples were obtained from pregnant women in the third trimester, for the isolation of exosomes by differential ultracentrifugation. Total exosomes were quantified using nanoparticle tracking analysis and immuno-reactive exosomal CD63 quantification. Placental-derived exosomes were quantified using placental alkaline phosphatase (PLAP) as a specific marker. The contribution of placental-derived exosomes to total exosomes in maternal plasma was determined by the ratio of PLAP⁺ exosomes to CD63⁺ exosomes.

RESULTS

The concentration of total exosomes significantly increased in early onset-PE and late onset-PE compared to N (≤33 weeks) and N (≥34 weeks). The relative concentration of placental-derived exosomes significantly increased in early onset-PE but decreased in late onset-PE compared to N. The ratio of PLAP⁺ exosomes to total number of exosomes significantly decreased in early onset-PE and late onset-PE. A positive correlation between total and placental-derived exosomes were obtained in N (≤33 weeks: Pearson's r = 0.60, ≥34 weeks: Pearson's r = 0.67) and early onset-PE (Pearson's r = 0.51, p < 0.05) with the inverse in late onset-PE (Pearson's r = -0.62, p < 0.01).

CONCLUSION

The differences in the contribution of placental-derived exosomes to total exosomes in maternal circulation suggests a possible pathophysiological role of placental-derived exosomes in pre-eclampsia.

Preeclampsia: What Does the Father Have to Do with It?

Preeclampsia (PE) is one of the leading causes of maternal and fetal morbidity and mortality, with incidence rates ranging between 2 and 5 % in the Western World. The exact causes of the disease remain largely unknown, because of the complex pathophysiologic mechanisms involved in the process. Genetic, environmental, and epigenetic parameters have been implicated by various authors as culprits for the pathogenesis of PE. Recent reports in the literature highlight the paternal role. Still, the exact extent and mechanism remain elusive. In this systematic review, we attempt to present data regarding the paternal role in a concise and comprehensive manner.

Increased tissue factor and thrombomodulin expression and histopathological changes in placentas of pregnancies with preeclampsia

INTRODUCTION

Preeclampsia has a global frequency of 2-8% and a frequency of 10% in developing countries. In Colombia, preeclampsia causes 42% of maternal mortality. Alterations in placental homeostasis have been proposed to be involved in its pathophysiology. The aim of this study was to compare mRNA and protein levels of tissue factor (F3) and thrombomodulin (THBD) and the histopathological findings of placentas.

MATERIALS AND METHODS

We studied 16 placentas from patients with preeclampsia and 19 term placentas with uncomplicated pregnancy. An expert pathologist, who was masked to the group assignment, conducted an evaluation to determine specific histological changes. Assessments of mRNA and protein levels of F3 and THBD were performed using real-time PCR and ELISA, respectively.

RESULTS

Cases and controls differed in the frequency of decidual arteriopathy (p = 0.027), acute infarction (p = 0.001) and hyperplasia of the syncytiotrophoblast (p = 0.0017). Cases had increased levels of F3 mRNA (p = 0.0124) and protein (p <  0.0001) and THBD mRNA (p <  0.0001) and protein (p <  0.0001).

CONCLUSION

In placenta of patients with preeclampsia, we detected abnormal expression of F3 and THBD with increased protein and mRNA levels. The role of these molecules in the pathogenesis of this disease and in alterations of hemostatic and histopathological aspects of placentas need further studying.

Syncytiotrophoblast Extracellular Vesicles from Pre-Eclampsia Placentas Differentially Affect Platelet Function

Pre-eclampsia (PE) complicates around 3% of all pregnancies and is one of the most common causes of maternal mortality worldwide. The pathophysiology of PE remains unclear however its underlying cause originates from the placenta and manifests as raised blood pressure, proteinuria, vascular or systemic inflammation and hypercoagulation in the mother. Women who develop PE are also at significantly higher risk of subsequently developing cardiovascular (CV) disease. In PE, the failing endoplasmic reticulum, oxidative and inflammatory stressed syncytiotrophoblast layer of the placenta sheds increased numbers of syncytiotrophoblast extracellular vesicles (STBEV) into the maternal circulation. Platelet reactivity, size and concentration are also known to be altered in some women who develop PE, although the underlying reasons for this have not been determined. In this study we show that STBEV from disease free placenta isolated ex vivo by dual placental perfusion associate rapidly with platelets. We provide evidence that STBEV isolated from normal placentas cause platelet activation and that this is increased with STBEV from PE pregnancies. Furthermore, treatment of platelets with aspirin, currently prescribed for women at high risk of PE to reduce platelet aggregation, also inhibits STBEV-induced reversible aggregation of washed platelets. Increased platelet reactivity as a result of exposure to PE placenta derived STBEVs correlates with increased thrombotic risk associated with PE. These observations establish a possible direct link between the clotting disturbances of PE and dysfunction of the placenta, as well as the known increased risk of thromboembolism associated with this condition.

The association between maternal antioxidant levels in midpregnancy and preeclampsia

OBJECTIVE

We sought to determine whether midpregnancy antioxidant levels are associated with preeclampsia, overall and by timing of onset.

STUDY DESIGN

We carried out a case-control study, nested within a cohort of 5337 pregnant women in Montreal, Quebec, Canada. Blood samples obtained at 24-26 weeks were assayed for nonenzymatic antioxidant levels among cases of preeclampsia (n = 111) and unaffected controls (n = 441). We excluded women diagnosed with gestational hypertension only. We used logistic regression with the z-score of each antioxidant level as the main predictor variable for preeclampsia risk. We further stratified early-onset (<34 weeks) and late-onset preeclampsia and carried out multinomial logistic regression. Finally, we assessed associations between antioxidant biomarkers and timing of onset (in weeks) by Cox regression, with appropriate selection weights. We summed levels of correlated biomarkers (r(2) > 0.3) and log-transformed positively skewed distributions. We adjusted for body mass index, nulliparity, preexisting diabetes, hypertension, smoking, and proxies for ethnicity and socioeconomic status.

RESULTS

The odds ratios for α-tocopherol, α-tocopherol:cholesterol, lycopene, lutein, and carotenoids (sum of α-carotene, β-carotene, anhydrolutein, α-cryptoxanthin, and β-cryptoxanthin) suggested an inverse association between antioxidant levels and overall preeclampsia risk; however, only lutein was significantly associated with overall preeclampsia in adjusted models (odds ratio, 0.60; 95% confidence interval, 0.46-0.77) per SD. In multinomial logistic models, the relative risk ratio (RRR) estimates for the early-onset subgroup were farther from the null than those for the late-onset subgroup. The ratio of α-tocopherol to cholesterol and retinol were significantly associated with early- but not late-onset preeclampsia: RRRs (95% confidence intervals) for early-onset preeclampsia 0.67 (0.46-0.99) and 1.61 (1.12-2.33), respectively. Lutein was significantly associated with both early- and late-onset subtypes in adjusted models; RRRs 0.53 (0.35-0.80) and 0.62 (0.47-0.82), respectively. Survival analyses confirmed these trends.

CONCLUSION

Most antioxidants were more strongly associated with early-onset preeclampsia, suggesting that oxidative stress may play a greater role in the pathophysiology of early-onset preeclampsia. Alternatively, reverse causality may explain this pattern. Lutein was associated with both early- and late-onset preeclampsia and may be a promising nutrient to consider in preeclampsia prevention trials, if this finding is corroborated.

Oxidative stress-induced C/EBPβ inhibits β-catenin signaling molecule involving in the pathology of preeclampsia

INTRODUCTION

Oxidative stress-induced trophoblast cell dysfunction is a major pathology in preeclampsia (PE). Recently, CCAAT/enhancer binding protein beta (C/EBPβ) has been investigated as a tumor suppressor that participates in tumor invasion. However, the function of C/EBPβ in trophoblast cells remains unknown. Our study was designed to detect the expression of C/EBPβ in the preeclamptic placenta and to identify the underlying mechanisms of oxidative stress.

METHODS

Human placental tissues with PE were collected. The expression of C/EBPβ and β-catenin were detected. Human first trimester extravillous trophoblast cell (HTR8/SVneo) line exposed to hypoxia/reoxygenation (H/R) was employed as an oxidative stress model in vitro to investigate the effects of C/EBPβ on invasion and the expression of β-catenin. Moreover, first trimester-derived placental villous explants were used to verify the effects of C/EBPβ and β-catenin in placentation.

RESULTS

In preeclamptic placentas, C/EBPβ was overexpressed and β-catenin was decreased. In addition, C/EBPβ was found to have increased expression in H/R-treated HTR8/SVneo cells and villous explants. C/EBPβ knockdown and β-catenin activation could significantly promote the invasion of HTR8/SVneo cells, enhance the outgrowth and migration in villous explants and inhibit the excessive generation of intracellular ROS. These findings might be related to the increased activities of MMP-2/9 and the decreased expression of TIMP-1/2. Meanwhile, C/EBPβ knockdown remarkably increased the expression of β-catenin.

DISCUSSION

We hypothesize that the oxidative stress-induced overexpression of C/EBPβ might influence the activity of MMPs by regulating the Wnt/β-catenin signaling pathway to affect the invasion of trophoblast cells, which then participate in the pathogenesis of preeclampsia.

Trophoblast expression of the minor histocompatibility antigen HA-1 is regulated by oxygen and is increased in placentas from preeclamptic women

INTRODUCTION

Maternal T-cells reactive towards paternally inherited fetal minor histocompatibility antigens are expanded during pregnancy. Placental trophoblast cells express at least four fetal antigens, including human minor histocompatibility antigen 1 (HA-1). We investigated oxygen as a potential regulator of HA-1 and whether HA-1 expression is altered in preeclamptic placentas.

METHODS

Expression and regulation of HA-1 mRNA and protein were examined by qRT-PCR and immunohistochemistry, using first, second, and third trimester placentas, first trimester placental explant cultures, and term purified cytotrophoblast cells. Low oxygen conditions were achieved by varying ambient oxygen, and were mimicked using cobalt chloride. HA-1 mRNA and protein expression levels were evaluated in preeclamptic and control placentas.

RESULTS

HA-1 protein expression was higher in the syncytiotrophoblast of first trimester as compared to second trimester and term placentas (P<0.01). HA-1 mRNA was increased in cobalt chloride-treated placental explants and purified cytotrophoblast cells (P = 0.04 and P<0.01, respectively) and in purified cytotrophoblast cells cultured under 2% as compared to 8% and 21% oxygen (P<0.01). HA-1 mRNA expression in preeclamptic vs. control placentas was increased 3.3-fold (P = 0.015). HA-1 protein expression was increased in syncytial nuclear aggregates and the syncytiotrophoblast of preeclamptic vs. control placentas (P = 0.02 and 0.03, respectively).

DISCUSSION

Placental HA-1 expression is regulated by oxygen and is increased in the syncytial nuclear aggregates and syncytiotrophoblast of preeclamptic as compared to control placentas. Increased HA-1 expression, combined with increased preeclamptic syncytiotrophoblast deportation, provides a novel potential mechanism for exposure of the maternal immune system to increased fetal antigenic load during preeclampsia.

Extracellular vesicles and reproduction-promotion of successful pregnancy

Extracellular vesicles (EVs) are membrane-bound complexes secreted from cells under both physiological and pathological conditions. They contain proteins, nucleic acids and lipids and act as messengers for cell–cell communication and signalling, particularly between immune cells. EV research is a rapidly evolving and expanding field, and it appears that all biological fluids contain very large numbers of EVs; they are produced from all cells that have been studied to date, and are known to have roles in several reproductive processes. This review analyses the evidence for the role of EVs throughout human reproduction, starting with the paternal and maternal gametes, followed by the establishment and continuation of successful pregnancies, with specific focus, where possible, on the interaction of EVs with the maternal immune system. Importantly, variations within the EV populations are identified in various reproductive disorders, such as pre-term labour and pre-eclampsia.