Role In Placental Dysfunction Research Articles

Whole transcriptome profiling of placental pathobiology in SARS-CoV-2 pregnancies identifies placental dysfunction signatures.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus infection in pregnancy is associated with higher incidence of placental dysfunction, referred to by a few studies as a 'preeclampsia-like syndrome'. However, the mechanisms underpinning SARS-CoV-2-induced placental malfunction are still unclear. Here, we investigated whether the transcriptional architecture of the placenta is altered in response to SARS-CoV-2 infection. We utilised whole-transcriptome, digital spatial profiling, to examine gene expression patterns in placental tissues from participants who contracted SARS-CoV-2 in the third trimester of their pregnancy (n = 7) and those collected prior to the start of the coronavirus disease 2019 (COVID-19) pandemic (n = 9). Through comprehensive spatial transcriptomic analyses of the trophoblast and villous core stromal cell subpopulations in the placenta, we identified SARS-CoV-2 to promote signatures associated with hypoxia and placental dysfunction. Notably, genes associated withvasodilation (NOS3), oxidative stress (GDF15, CRH) and preeclampsia (FLT1, EGFR, KISS1, PAPPA2) were enriched with SARS-CoV-2. Pathways related to increased nutrient uptake, vascular tension, hypertension and inflammation were also enriched in SARS-CoV-2 samples compared to uninfected controls. Our findings demonstrate the utility of spatially resolved transcriptomic analysis in defining the underlying pathogenic mechanisms of SARS-CoV-2 in pregnancy, particularly its role in placental dysfunction. Furthermore, this study highlights the significance of digital spatial profiling in mapping the intricate crosstalk between trophoblasts and villous core stromal cells, thus shedding light on pathways associated with placental dysfunction in pregnancies with SARS-CoV-2 infection.

Placental OLAH Levels Are Altered in Fetal Growth Restriction, Preeclampsia and Models of Placental Dysfunction

Previously, we identified elevated transcripts for the gene Oleoyl-ACP Hydrolase (OLAH) in the maternal circulation of pregnancies complicated by preterm fetal growth restriction. As placental dysfunction is central to the pathogenesis of both fetal growth restriction and preeclampsia, we aimed to investigate OLAH levels and function in the human placenta. We assessed OLAH mRNA expression (qPCR) throughout pregnancy, finding placental expression increased as gestation progressed. OLAH mRNA and protein levels (Western blot) were elevated in placental tissue from cases of preterm preeclampsia, while OLAH protein levels in placenta from growth-restricted pregnancies were comparatively reduced in the preeclamptic cohort. OLAH expression was also elevated in placental explant tissue, but not isolated primary cytotrophoblast cultured under hypoxic conditions (as models of placental dysfunction). Further, we discovered that silencing cytotrophoblast OLAH reduced the expression of pro- and anti-apoptosis genes, BAX and BCL2, placental growth gene, IGF2, and oxidative stress gene, NOX4. Collectively, these findings suggest OLAH could play a role in placental dysfunction and may be a therapeutic target for mitigating diseases associated with this vital organ. Further research is required to establish the role of OLAH in the placenta, and whether these changes may be a maternal adaptation or consequence of disease.

Fear Stress During Pregnancy Affects Placental m6A-Modifying Enzyme Expression and Epigenetic Modification Levels

As the hub connecting mother and offspring, the placenta’s normal development is vital for fetal growth. Fear stress can cause some structural alterations in the placenta and affect placental development and function. N6-methyladenosine (m6A) is the most common mRNA modification and is involved in regulating the development of the placenta and embryo. There are no reports on the potential role of m6A modification in placental damage caused by fear stress during pregnancy. In this study, we demonstrated that fear stress during pregnancy increases the levels of methylated enzymes (METTL3, METTL14, and WTAP), decreases the levels of demethylase FTO, and increases the overall methylation levels in the placenta of pregnant rats. MeRIP-seq data analysis revealed 22,010 m6A peaks associated with 12,219 genes in the placenta of the model and 21,060 m6A peaks associated with 11,730 genes in the placenta of the control. The peaks were mainly concentrated in the coding region and the 3ʹ untranslated region. In addition, 50 genes with abnormal modification and expression (double aberrant genes) were screened out by combining MeRIP-seq and RNA-seq data. Mefv, Erbb2, and Cgas were selected from 50 double aberrant genes, and MeRIP-qPCR and real-time quantitative polymerase chain reaction were used to verify their modification and expression levels. Our findings suggest that m6A modifications play an important role in placental dysfunction induced by fear stress during pregnancy.

DAAM2 is elevated in the circulation and placenta in pregnancies complicated by fetal growth restriction and is regulated by hypoxia

Previously, we identified increased maternal circulating DAAM2 mRNA in pregnancies complicated by preterm fetal growth restriction (FGR). Here, we assessed whether circulating DAAM2 mRNA could detect FGR, and whether the DAAM2 gene, known to play roles in the Wnt signalling pathway is expressed in human placenta and associated with dysfunction and FGR. We performed linear regression analysis to calculate area under the ROC curve (AUC) for DAAM2 mRNA expression in the maternal circulation of pregnancies complicated by preterm FGR. DAAM2 mRNA expression was assessed across gestation by qPCR. DAAM2 protein and mRNA expression was assessed in preterm FGR placenta using western blot and qPCR. DAAM2 expression was assessed in term cytotrophoblasts and placental explant tissue cultured under hypoxic and normoxic conditions by qPCR. Small interfering RNAs were used to silence DAAM2 in term primary cytotrophoblasts. Expression of growth, apoptosis and oxidative stress genes were assessed by qPCR. Circulating DAAM2 mRNA was elevated in pregnancies complicated by preterm FGR [p < 0.0001, AUC = 0.83 (0.78–0.89)]. Placental DAAM2 mRNA was detectable across gestation, with highest expression at term. DAAM2 protein was increased in preterm FGR placentas but demonstrated no change in mRNA expression. DAAM2 mRNA expression was increased in cytotrophoblasts and placental explants under hypoxia. Silencing DAAM2 under hypoxia decreased expression of pro-survival gene, BCL2 and oxidative stress marker, NOX4, whilst increasing expression of antioxidant enzyme, HMOX-1. The increased DAAM2 associated with FGR and hypoxia implicates a potential role in placental dysfunction. Decreasing DAAM2 may have cytoprotective effects, but further research is required to elucidate its role in healthy and dysfunctional placentas.

Hypoxia and Mitochondrial Dysfunction in Pregnancy Complications.

Hypoxia is a common and severe stress to an organism’s homeostatic mechanisms, and hypoxia during gestation is associated with significantly increased incidence of maternal complications of preeclampsia, adversely impacting on the fetal development and subsequent risk for cardiovascular and metabolic disease. Human and animal studies have revealed a causative role of increased uterine vascular resistance and placental hypoxia in preeclampsia and fetal/intrauterine growth restriction (FGR/IUGR) associated with gestational hypoxia. Gestational hypoxia has a major effect on mitochondria of uteroplacental cells to overproduce reactive oxygen species (ROS), leading to oxidative stress. Excess mitochondrial ROS in turn cause uteroplacental dysfunction by damaging cellular macromolecules, which underlies the pathogenesis of preeclampsia and FGR. In this article, we review the current understanding of hypoxia-induced mitochondrial ROS and their role in placental dysfunction and the pathogenesis of pregnancy complications. In addition, therapeutic approaches selectively targeting mitochondrial ROS in the placental cells are discussed.

174 Association between paternal health and severe maternal morbidity: analysis of US claims data

A critical paternal role in placental dysfunction and pre-eclampsia has been reported and attributed to immunologic and genetic factors. Our objective was to examine the hypothesis that paternal health is associated with abnormal placentation, pre-eclampsia and severe maternal morbidity (SMM). Retrospective analysis of live births from 2007-2016 among women 20-45 years of age in the IBM Marketscan® research database. Infants were linked to paired mothers and fathers using family ID. Preconception paternal health was assessed using the number of metabolic syndrome (MetS) diagnostic criteria and the most common individual chronic disease diagnoses (hypertension, diabetes mellitus, obesity, hyperlipidemia, COPD, cancer, and depression). Adverse pregnancy outcomes assessed included: 1) abnormal placentation including placenta accreta spectrum, placenta previa and placental abruption, 2) pre-eclampsia with severe features and eclampsia, and 3) SMM, identified as any indicator from the CDC Index except blood transfusion alone, which has been found to overestimate true cases. The association between paternal health and maternal pregnancy outcomes was determined using logistic regression models estimated with generalized estimating equations adjusted for maternal age, region, birth year, maternal obesity, smoking, parity and average number of outpatient visits per year. Among 785,809 births, preconception paternal health was significantly associated with all adverse pregnancy outcomes (Table 1). The odds of SMM were 57% higher (95% CI 1.16-2.13) for women whose partners had 5 or more chronic diseases than for women whose partners did not have a chronic disease. Furthermore, the magnitude of risk of SMM increased with preconception paternal comorbidities in a dose-dependent fashion. Preconception paternal health is associated with abnormal placentation, pre-eclampsia and SMM, suggesting that paternally derived factors may play significant roles in placentation and the subsequent development of adverse pregnancy outcomes.

Combining Biomarkers to Predict Pregnancy Complications and Redefine Preeclampsia: The Angiogenic-Placental Syndrome.

Placental dysfunction underlies a spectrum of perinatal pathologies, including preeclampsia and fetal growth restriction. Angiogenesis-related factors, including sFlt-1 (soluble fms-like tyrosine kinase 1) and PlGF (placental growth factor), play an important role in placental dysfunction; altered levels are detectable several weeks before onset of pregnancy complications. In vitro diagnostic tests for these biomarkers can improve early diagnosis and facilitate prediction of maternal and fetal outcomes. We assessed evidence for combining angiogenic biomarkers with other biomarkers or clinical parameters to predict maternal/fetal outcomes in pregnant women with placental dysfunction. Pooled information on placental perfusion (ultrasonography, mean arterial pressure), clinical characteristics, and biomarker levels (PlGF) can improve first-trimester prediction and preeclampsia diagnosis. Angiogenic factors (sFlt-1/PlGF ratio; PlGF alone) with or without clinical characteristics can facilitate second-/third-trimester prediction of early-onset and late-onset preeclampsia. A combination of increased sFlt-1/PlGF ratio and ultrasound can rule out early fetal growth restriction. The sFlt-1/PlGF ratio is also a reliable tool for discriminating between pregnancy-related hypertensive disorders, including superimposed preeclampsia and gestational hypertension. Analysis of angiogenic factors with or without uterine Doppler substantially improves sensitivity and specificity for predicting adverse outcomes and iatrogenic preterm delivery. We propose to extend the American College of Obstetricians and Gynecologists definition of preeclampsia in the future to include the combination of new-onset hypertension and new-onset of altered angiogenic factors (sFlt-1/PlGF ratio or PlGF alone). In summary, altered angiogenic biomarkers indicate placental dysfunction, and their implementation into clinical practice will help reduce the considerable burden of morbidity and mortality associated with adverse pregnancy outcomes as a consequence of angiogenic-placental syndrome.

1037: Betamethasone reverses vasopressin induced inhibition of trophoblast migration

Elevated arginine vasopressin (AVP) is predictive of human preeclampsia (PreE) and causes a PreE phenotype in mice. Betamethasone (BMTZ), a corticosteroid administered to prevent preterm birth complications, inhibits AVP and stimulates serum/glucocorticoid regulated kinase 1 (SGK1), a serine/threonine kinase. In the AVP mouse model of PreE, early administration of BMTZ prevents preeclampsia. The objective of this study was to determine if BMTZ acts through SGK1 to inhibit the effects of AVP on trophoblast cell migration. Trophoblast migration was assessed using a human extravillous trophoblast cell line HTR-8/SVneo. Cells were plated into ibidi 2-well silicone inserts and allowed to adhere for 24 hours before removal of the insert creating a 500mm gap for migration analysis and treatment. Cells were treated with saline (n=7), AVP (n=7), AVP + BMTZ (n=3), or AVP + BMTZ + SGK1 inhibitor (n=3). Images were taken at 0 and 24 hours post-treatment. All wells were set up in duplicate and averaged for n=1. The area of the gap was measured and the percent closure for cell migration was calculated. Two-tailed Student t test or one way ANOVA multiple comparisons were performed with alpha=0.05. AVP treatment of trophoblast cells inhibited migration at 24 hours (Saline: 38% vs AVP: 25%, n=7 p< 0.05). Treatment of trophoblast cells with BMTZ prevented AVP induced inhibition of trophoblast migration (AVP: 25% n=7 vs AVP + BMTZ: 40% n=3, p< 0.05) with migration rates comparable to saline-treated cells (saline: 38% n=7 vs AVP + BMTZ: 40% n=3, p=0.99). The effect of BMTZ on AVP-induced inhibition of trophoblast cell migration was not mediated via SGK1 (AVP + BMTZ: 40% vs AVP + BMTZ + SGK1 inhibitor: 49%, n=3, p=0.51). These data demonstrate that AVP may play a role in placental dysfunction via inhibition of trophoblast migration. While BMTZ is sufficient to prevent the impaired trophoblast migration via AVP, these effects are mediated through a SGK1 independent mechanism.

Cardiovascular Programming During and After Diabetic Pregnancy: Role of Placental Dysfunction and IUGR.

Intrauterine growth restriction (IUGR) is a condition whereby a fetus is unable to achieve its genetically determined potential size. IUGR is a global health challenge due to high mortality and morbidity amongst affected neonates. It is a multifactorial condition caused by maternal, fetal, placental, and genetic confounders. Babies born of diabetic pregnancies are usually large for gestational age but under certain conditions whereby prolonged uncontrolled hyperglycemia leads to placental dysfunction, the outcome of the pregnancy is an intrauterine growth restricted fetus with clinical features of malnutrition. Placental dysfunction leads to undernutrition and hypoxia, which triggers gene modification in the developing fetus due to fetal adaptation to adverse utero environmental conditions. Thus, in utero gene modification results in future cardiovascular programming in postnatal and adult life. Ongoing research aims to broaden our understanding of the molecular mechanisms and pathological pathways involved in fetal programming due to IUGR. There is a need for the development of effective preventive and therapeutic strategies for the management of growth-restricted infants. Information on the mechanisms involved with in utero epigenetic modification leading to development of cardiovascular disease in adult life will increase our understanding and allow the identification of susceptible individuals as well as the design of targeted prevention strategies. This article aims to systematically review the latest molecular mechanisms involved in the pathogenesis of IUGR in cardiovascular programming. Animal models of IUGR that used nutrient restriction and hypoxia to mimic the clinical conditions in humans of reduced flow of nutrients and oxygen to the fetus will be discussed in terms of cardiac remodeling and epigenetic programming of cardiovascular disease. Experimental evidence of long-term fetal programming due to IUGR will also be included.

The possible role of cytomegalovirus infection and pro-inflammatory IL_2 cytokine in preeclampsia

Background and Objective: Fragmentary evidence suggests that trophoblast viral infection may play a role in placental dysfunction leading to complications like Preeclampsia. Among these, placental exposure to CMV induces an inflammatory response that precedes invasive trophoblast cell death. This study aimed to assess the frequency of anti-CMV IgG seropositivity and IL2 level in serum in patients with preeclampsia compared to normotensive control pregnant women. Methods: A total of 90 women were enrolled, of which 60 had preeclampsia and 30 normotensive pregnant women as the control. A serum sample was collected from each subject and was investigated for anti-CMV IgG serostatus and IL-2 concentration using Enzyme-Linked Immunosorbent Assay (ELISA) based kits. Results: In preeclamptic and normotensive pregnant women, 33.3% and 16.6% of the tested sera were seropositive for anti CMV IgG antibodies respectively (P = 0.136). Early onset preeclamptic women revealed a high frequency of anti-CMV seropositivity (80%) when compared with late onset Preeclampsia (20%). Cytokine assessment revealed a higher IL-2 level in preeclamptic women seropositive for anti-CMV IgG although statistically was not significant (P = 0.14), but in normotensive women, the IL-2 level was significantly higher in sera seropositive for anti-CMV IgG (P = 0.02). Conclusion: This study delineates a high frequency of anti-CMV IgG antibodies particularly those with early onset preeclampsia; with no significant difference for the IL-2 level.

Loss of Thrombomodulin in Placental Dysfunction in Preeclampsia.

Preeclampsia is a pregnancy-specific syndrome characterized by placental dysfunction and an angiogenic imbalance. Systemically, levels of thrombomodulin, an endothelium- and syncytiotrophoblast-bound protein that regulates coagulation, inflammation, apoptosis, and tissue remodeling, are increased. We aimed to investigate placental thrombomodulin dysregulation and consequent downstream effects in the pathogenesis of preeclampsia. Placentas from 28 preeclampsia pregnancies, 30 uncomplicated pregnancies, and 21 pregnancies complicated by growth restriction as extra controls were included. Immunohistochemical staining of thrombomodulin, caspase-3, and fibrin was performed. Placental mRNA expression of thrombomodulin, inflammatory markers, matrix metalloproteinases 2 and 9, and soluble Flt-1 were measured with quantitative polymerase chain reaction. Thrombomodulin mRNA expression was determined in vascular endothelial growth factor-transfected trophoblast cell lines. Thrombomodulin protein and mRNA expression were decreased in preeclampsia as compared with both control groups (P=0.001). Thrombomodulin mRNA expression correlated with maternal body mass index (P<0.01) and diastolic blood pressure (P<0.05) in preeclampsia. An increase in placental apoptotic cells was associated with preeclampsia (P<0.001). Thrombomodulin expression correlated positively with matrix metalloproteinase expression (P<0.01) in preeclampsia, but not with fibrin deposits or inflammatory markers. Placental soluble Flt-1 expression correlated with decreased thrombomodulin expression. Vascular endothelial growth factor induced upregulation of thrombomodulin expression in trophoblast cells. Decreased thrombomodulin expression in preeclampsia may play a role in placental dysfunction in preeclampsia and is possibly caused by an angiogenic imbalance. Hypertension and obesity are associated with thrombomodulin downregulation. These results set the stage for further basic and clinical research on thrombomodulin in the pathogenesis of preeclampsia and other syndromes characterized by endothelial dysfunction.

443: The role of placental dysfunction in the pathogenesis of IUGR

443: The role of placental dysfunction in the pathogenesis of IUGR

The ever growing complexity of placental epigenetics – Role in adverse pregnancy outcomes and fetal programming

As the primary interface between maternal and fetal circulations, the placenta is subject to a myriad of environmental exposures with the capacity to alter placental function and fetal development. Many of these effects are likely to be mediated by epigenetic (‘above DNA’) change, which is also in turn regulated by maternal and fetal genetic factors. Linking specific environmental exposures, genetic, and epigenetic variation to maternal and fetal outcomes may provide valuable mechanistic insights into the role of placental dysfunction in pregnancy-associated disease and later health. The complexities are manifold but are rapidly being overcome by technological advances and emerging analytical approaches. Although focussing on recent genome-scale and gene-specific DNA methylation studies in the human placenta, this review also discusses the potential of a future broader exploration of combined environmental, genetic and epigenomic approaches, encompassing higher order epigenetic modifications, for unravelling the molecular mechanisms underlying gene-environment interaction at the fetomaternal interface.

Short telomeres may play a role in placental dysfunction in preeclampsia and intrauterine growth restriction

Telomeres shorten and aggregate with cellular senescence and oxidative stress. Telomerase and its catalytic component human telomerase reverse-transcriptase regulate telomere length. The pathogenesis of preeclampsia and intrauterine growth restriction involves hypoxic stress. We aimed to assess telomere length in trophoblasts from pregnancies with those complications. Placental specimens from 4 groups of patients were studied: severe preeclampsia, intrauterine growth restriction, preeclampsia combined with intrauterine growth restriction, and uncomplicated (control). Telomere length and human telomerase reverse-transcriptase expression were assessed by using quantitative fluorescence-in-situ protocol and immunohistochemistry. Telomere length was significantly lower in preeclampsia, intrauterine growth restriction, and preeclampsia plus intrauterine growth restriction placentas. More aggregates were found in preeclampsia, but not in intrauterine growth restriction placentas. Human telomerase reverse-transcriptase was significantly higher in the controls compared with the other groups. Telomeres are shorter in placentas from preeclampsia and intrauterine growth restriction pregnancies. Increased telomere aggregate formation in preeclampsia but not in intrauterine growth restriction pregnancies, implies different placental stress-related mechanisms in preeclampsia with or without intrauterine growth restriction.

64: Short telomeres may play a role in placental dysfunction in preeclampsia and intra uterine growth restriction

64: Short telomeres may play a role in placental dysfunction in preeclampsia and intra uterine growth restriction

Fetal Stress Response to Fetal Cardiac Surgery

A deleterious fetal stress response, although not fully elucidated, may account for poor outcomes after experimental fetal cardiac surgery. We set out to characterize this fetal stress response and its potential role in placental dysfunction. Fifteen ovine fetuses at gestational day 100 to 114 were placed on extracorporeal support for 30 minutes and were then followed 2 hours after cardiopulmonary bypass. Fetal plasma samples were analyzed for vasopressin, cortisol, and beta-endorphin levels, and correlated to fetal hemodynamics and placental gas exchange. Unique temporal patterns of response were seen in release of the three stress hormones. Vasopressin demonstrated the most profound and early response followed by cortisol and beta-endorphin, the latter continuing to rise in the post-bypass period. A sharp rise in fetal mean arterial pressure and placental vascular resistance strongly correlated with rising vasopressin levels. Post-bypass deterioration of fetal gas exchange and hemodynamics correlated with the ensuing rise in cortisol and beta-endorphin. Rising fetal lactate levels correlated with elevations in all three stress hormones. Fetal cardiopulmonary bypass leads to a profound, early rise in vasopressin concentrations that strongly correlates with placental dysfunction after fetal bypass. Vasopressin may play an important mechanistic role in pathogenesis of this placental dysfunction.

Cytokine Response to Fetal Cardiac Bypass † 133

Cytokines (IL-1s, IL-6, and IL-8) have been associated with the systemic inflammatory response syndrome known to occur in patients undergoing cardiopulmonary bypass. We hypothesized that the placental dysfunction which has been found to complicate fetal cardiac bypass (FCB) may be in part a function of a cytokine mediated acute phase reaction. To test this hypothesis, we conducted a controlled study to characterize the effect of cardiac bypass on plasma levels of IL-1s, IL-6, and IL-8 in fetal sheep. 9 mixed-breed pregnant ewes at 118-122 days of gestation were assigned randomly to either of 2 groups: `fetal cardiac bypass group' (n=5) or `control group' (n=4). After surgical exposure and instrumentation, previously described techniques were used to perform 30 minutes of FCB in study group fetuses, while control group fetuses were exposed and instrumented identically, but did not undergo bypass. Placental and systemic hemodynamics were monitored in both groups. Pre- and post-FCB blood samples were analyzed for IL-1β, IL-6, and IL-8 using previously described ELISA protocols. Pre-FCB IL-6 levels were zero in all study and control fetuses. IL-6 levels consistently increased in all study animals (to an average post-FCB level of 53.0±24.2 pg/ml; p=.01), while they remained at zero in all control animals. FCB produced no significant changes in IL-1s and 8. The decrease in placental blood flow (PBF) from pre- to post-FCB in study group fetuses (33.3±6.4 ml/kg) was significantly greater than the decrease in control fetuses (9.3±2.3 ml/kg; p=.0002). Placental vascular resistance (PVR) increased significantly(from.43±.11 pre-FCB to.52±.14 post-FCB; p=.01) in study group fetuses, but was essentially unchanged (.388±.10 pre-FCB to.394±.10 post-FCB; p=.40) in control fetuses. The difference in PVR changes between the 2 groups was highly significant (p=.004). In conclusion, FCB produces significant and consistent increases in fetal plasma IL-6, which correspond with increased PVR and decreased PBF. It appears that IL-6 may have an important role in placental dysfunction during and after FCB. Further investigation is necessary to elucidate its specific role in the impairment of placental function or as a marker of placental injury.