Association of fetal-derived hypermethylated RASSF1A concentration in placenta-mediated pregnancy complications

Examining the predictive value of fetal fraction on hypertensive disorders of pregnancy

BACKGROUND

Cell-free fetal DNA (cffDNA) screening is routinely performed in pregnancy. Abnormal fetal fraction has been associated with adverse pregnancy outcomes, including hypertensive disorders of pregnancy, which are associated with severe maternal and neonatal morbidity and mortality.

OBJECTIVE

This study examined whether abnormal fetal fraction, defined in this study as fetal fraction either <6 or >15 on the basis of restricted-cubic-spline-plot within our study population, was associated with HDP in a retrospective sample, as well as whether fetal fraction improves the prediction of hypertensive disorders of pregnancy (HDP). We hypothesized that abnormal fetal fraction would be associated with HDP and that adding fetal fraction to a model would significantly improve its strength to predict HDP.

STUDY DESIGN

This was a retrospective cohort study of 729 patients delivering singleton, non-anomalous pregnancies with conclusive cffDNA screening. The primary outcome was HDP. Logistic regression models tested associations between fetal fraction and HDP. We evaluated the impact of including fetal fraction on the prediction of hypertensive disorders of pregnancy (HDP) by comparing the area under the receiver operating characteristic (ROC) curve (AUC) between predictive models with and without fetal fraction.

RESULTS

Among the study sample, there was an HDP rate of 11.5 %. Abnormal fetal fraction was defined as <6 % percentile and >15 %, HDP incidence was significantly higher in patients with fetal fraction <6 % compared to patients with fetal fraction in normal range (fetal fraction 6-15 %) (19.5 % vs 10.7 %, p = 0.006 on post hoc comparison). Model 1 had one predictor (fetal fraction) with an AUC of 0.59, Model 2 had three predictors (BMI, nulliparity, history of HDP) with an AUC of 0.71, and Model 3 had four predictors (BMI, nulliparity, history of HDP, and fetal fraction) with an AUC of 0.73. Models 2 and 3 were not significantly different (p = 0.18).

CONCLUSIONS

More patients who developed HDP had low fetal fraction and fewer patients who developed HDP had high fetal fraction compared to those patients who did not develop HDP. Based on results from multivariable regression models, we cannot conclude that fetal fraction improves HDP prediction. However, developing standardized values for abnormal fetal fraction may be clinically useful.

Association between fetal fraction of cell-free DNA and adverse pregnancy outcomes

PURPOSE

To determine the association between fetal fraction (FF) levels in cell-free fetal DNA (cffDNA) testing and adverse pregnancy outcomes.

METHODS

This retrospective cohort study, conducted at a single center, involved 2063 pregnant women with normal 1st and 2nd trimester non-invasive prenatal test (NIPT) results between 2016 and 2021. Pregnancy outcomes were examined by determining the  < 4% and  < 5th percentile (3.6%) cut-off values for low fetal fraction (LFF). Pregnancy outcomes were also examined by dividing the FF into population-based quartiles. Adverse pregnancy outcomes were pregnancy-induced hypertensive diseases (PIHD), gestational diabetes mellitus (GDM), spontaneous preterm birth (PTB), intrahepatic cholestasis of pregnancy (ICP), small for gestational age (SGA), large for gestational age (LGA), low birth weight (LBW), macrosomia, and 1st and 5th minutes low APGAR scores (< 7).

RESULTS

PIHD was significantly higher in LFF (< 4% and  < 5th percentile) cases (p = 0.015 and p < 0.001, respectively). However, in population-based quartiles of FF, PIHD did not differ significantly between groups. Composite adverse maternal outcomes were significantly higher in the FF < 4% group (p = 0.042). When analyzes were adjusted for maternal age, BMI, and gestational age at NIPT, significance was maintained at  < 4%,  < 5th percentile LFF for PIHD, and  < 4% LFF for composite adverse maternal outcomes. However, there was no significant relationship between LFF with GDM, ICP and PTB. Additionally, there was no significant association between low APGAR scores, SGA, LGA, LBW, macrosomia, and LFF concerning neonatal outcomes.

CONCLUSION

Our study showed that LFF in pregnant women with normal NIPT results may be a predictor of subsequent PIHD.

DNA methylation landscape in pregnancy-induced hypertension: progress and challenges

Gestational hypertension (PIH), especially pre-eclampsia (PE), is a common complication of pregnancy. This condition poses significant risks to the health of both the mother and the fetus. Emerging evidence suggests that epigenetic modifications, particularly DNA methylation, may play a role in initiating the earliest pathophysiology of PIH. This article describes the relationship between DNA methylation and placental trophoblast function, genes associated with the placental microenvironment, the placental vascular system, and maternal blood and vascular function, abnormalities of umbilical cord blood and vascular function in the onset and progression of PIH, as well as changes in DNA methylation in the progeny of PIH, in terms of maternal, fetal, and offspring. We also explore the latest research on DNA methylation-based early detection, diagnosis and potential therapeutic strategies for PIH. This will enable the field of DNA methylation research to continue to enhance our understanding of the epigenetic regulation of PIH genes and identify potential therapeutic targets.

Obstetrical, perinatal, and genetic outcomes associated with nonreportable prenatal cell-free DNA screening results

BACKGROUND

The clinical implications of nonreportable cell-free DNA screening results are uncertain, but such results may indicate poor placental implantation in some cases and be associated with adverse obstetrical and perinatal outcomes.

OBJECTIVE

This study aimed to assess the outcomes of pregnancies with nonreportable cell-free DNA screening in a cohort of patients with complete genetic and obstetrical outcomes.

STUDY DESIGN

This was a prespecified secondary analysis of a multicenter prospective observational study of prenatal cell-free DNA screening for fetal aneuploidy and 22q11.2 deletion syndrome. Participants who underwent cell-free DNA screening from April 2015 through January 2019 were offered participation. Obstetrical outcomes and neonatal genetic testing results were collected from 21 primary-care and referral centers in the United States, Europe, and Australia. The primary outcome was risk for adverse obstetrical and perinatal outcomes (aneuploidy, preterm birth at <28, <34, and <37 weeks' gestation, preeclampsia, small for gestational age or birthweight <10th percentile for gestational week, and a composite outcome that included preterm birth at <37 weeks, preeclampsia, small for gestational age, and stillbirth at >20 weeks) after nonreportable cell-free DNA screening because of low fetal fraction or other causes. Multivariable analyses were performed, adjusting for variables known to be associated with obstetrical and perinatal outcomes, nonreportable results, or fetal fraction.

RESULTS

In total, 25,199 pregnant individuals were screened, and 20,194 were enrolled. Genetic confirmation was missing in 1165 (5.8%), 1085 (5.4%) were lost to follow-up, and 93 (0.5%) withdrew; the final study cohort included 17,851 (88.4%) participants who had cell-free DNA, fetal or newborn genetic confirmatory testing, and obstetrical and perinatal outcomes collected. Results were nonreportable in 602 (3.4%) participants. A sample was redrawn and testing attempted again in 427; in 112 (26.2%) participants, results were again nonreportable. Nonreportable results were associated with higher body mass index, chronic hypertension, later gestational age, lower fetal fraction, and Black race. Trisomy 13, 18, or 21 was confirmed in 1.6% with nonreportable tests vs 0.7% with reported results (P=.013). Rates of preterm birth at <28, 34, and 37 weeks, preeclampsia, and the composite outcome were higher among participants with nonreportable results, and further increased among those with a second nonreportable test, whereas the rate of small for gestational age infants was not increased. After adjustment for confounders, the adjusted odds ratios were 2.2 (95% confidence interval, 1.1-4.4) and 2.6 (95% confidence interval, 0.6-10.8) for aneuploidy, and 1.5 (95% confidence interval, 1.2-1.8) and 2.1 (95% confidence interval, 1.4-3.2) for the composite outcome after a first and second nonreportable test, respectively. Of the patients with nonreportable tests, 94.9% had a live birth, as opposed to 98.8% of those with reported test results (adjusted odds ratio for livebirth, 0.20 [95% confidence interval, 0.13-0.30]).

CONCLUSION

Patients with nonreportable cell-free DNA results are at increased risk for a number of adverse outcomes, including aneuploidy, preeclampsia, and preterm birth. They should be offered diagnostic genetic testing, and clinicians should be aware of the increased risk of pregnancy complications.

Use of cell-free signals as biomarkers for early and easy prediction of preeclampsia

Introduction

Preeclampsia (PE) is a leading cause of maternal and perinatal morbidity worldwide. However, current methods of screening are complicated and require special skill sets. In this observational study of prospectively collected samples, we wanted to evaluate if cell-free (cf) DNA could be an efficient biomarker for identification of at-risk patients.

Methods

One hundred patients attending a private prenatal clinic in Canada were enrolled in their first trimester of pregnancy and a blood draw was carried out at 11 + 0 to 14 + 2 weeks' (timepoint A) and 17 + 6 to 25 + 5 weeks of gestation (timepoint B). CfDNA signals, namely concentration, fetal fraction, and fragment size distribution, were correlated with clinical outcomes in the test population to develop the logistic regression model.

Results

Twelve patients developed PE-four early-stage and eight late-stage PE. Significant differences were observed between PE patients and control cases for all three cfDNA signals at timepoint A, while both fetal fraction and concentration were significantly different between PE patients and control cases at timepoint B. Overall, the model had a sensitivity of up to 100% and specificity of up to 87.5% at Timepoint A.

Conclusion

This proof-of-principle study showed that use of this logistic regression model could identify patients at risk of preeclampsia in the first trimester of pregnancy.

Evaluation of umbilical cord immune cells in pregnancies with autoimmune disorders and/or methylenetetrahydrofolate reductase polymorphisms

OBJECTIVES

To evaluate umbilical cord immune cells in pregnancies with autoimmune disorders (AID) and/or methylenetetrahydrofolate reductase (MTHFR) polymorphisms.

METHODS

Umbilical cords were obtained from seven AID women without MTHFR polymorphisms, eight with AID and MTHFR polymorphisms, nine with MTHFR polymorphisms, and eight with neither. Umbilical cords were assessed immunohistologcally by anti-CD4, anti-CD8, anti-CD14, anti-CD19, anti-CD21, and anti-CD56 antibodies in six umbilical cord zones: 1) arterial wall 2) periarterial zone 3) venous wall 4) perivenous zone 5) intervascular zone, and 6) subamniotic zone.

RESULTS

AIDs and MTHFR polymorphisms had an effect on the number and composition of CD4+ cells in the venous wall. The presence of a MTHFR polymorphism may affect the number and morphology of CD4+ cells in the subamniotic zone. CD8+ cell distribution is substantially influenced by the presence of maternal risk factors. The co-existence of AID with MTHFR polymorphism has a prominent effect on the number and morphology of CD14+ cells, especially in the arterial wall. CD19+ cells were only observed in the control group in the venous wall, perivenous zone, and intervascular zone. CD21+ cells were only observed in the arterial wall of the control group and the intervascular zone of the AID group with different morphologic features. The number and morphology of CD56+ cells is prominently affected by the presence of maternal risk factors.

CONCLUSIONS

Umbilical cord stem cell and immune cell composition may be affected by the presence of risk factors like MTHFR polymorphisms and/or AID.

Association between Levels of Total Cell-Free DNA and Development of Preeclampsia-A Literature Review

Objectives  The aim of the study is to synthesize the evidence and evaluate the total cell-free deoxyribonucleic (cfDNA) associated with the prediction of preeclampsia (PE). Total cfDNA is constituted by both cell-free fetal DNA (cffDNA) originated mainly from the placenta, and maternal cfDNA derived from maternal leukocytes. Methods  A systematic review was conducted by searching PubMed and Medline. Literature reporting levels of total cfDNA in the development of PE was included. Studies that only reported cffDNA, but no cfDNA concentrations were not included in this review. Results  Eight studies were included. Seven reported values of cfDNA in PE patients, regardless of early or late onset PE, six of which demonstrated a significant increase of cfDNA in patients who subsequently developed PE. Seven studies evaluated cfDNA levels in the first trimester, six of which showed significant increase of cfDNA concentrations in women who later developed PE. Five studies investigated cfDNA levels in the second trimester, all presenting increased total cfDNA levels in the PE group compared with normal controls. Conclusion  Total cfDNA may play a role as a biochemical marker of PE, compared with fetal cfDNA. Large prospective studies with homogeneous populations and standardized methodology are needed to further confirm its predictive value.

Comparison of VEGF-A values between pregnant women with COVID-19 and healthy pregnancies and its association with composite adverse outcomes

The aim is to compare VEGF-A values between pregnant women with coronavirus disease 2019 (COVID-19) and healthy controls. Furthermore, the association of inflammation parameters, disease severity, and obstetric complications with VEGF-A was investigated. This prospective case-control study was conducted on pregnant women who were admitted to Ankara City Hospital between June 14, 2020 and August 28, 2020. Pregnant women with COVID-19 (n = 95) were compared with a control group of healthy pregnant women (n = 92) with similar clinical and demographic characteristics. Demographic features, clinical characteristics, laboratory test results, VEGF-A values were compared between the groups. A correlation analysis was performed between VEGF-A levels, inflammation parameters, and clinical characteristics of the cases for pregnant women with COVID-19. VEGF-A levels were also compared between patients with composite adverse outcome and patients without any complication in the COVID-19 group. The two groups were similar except for obstetric complications (p > .05). The obstetric complication rate was higher in the COVID-19 group (p =.02). The two groups were comparable in terms of neutrophil to lymphocyte ratio and VEGF-A values. VEGF-A values were slightly different between the trimesters. A negative moderate statistically significant correlation was found between the neutrophil and VEGF-A values (r = -0.231, p =.02). VEGF-A values were similar between patients with and without composite adverse outcomes (p > .05). VEGF-A values were similar between pregnant women with COVID-19 and healthy controls.

Implications of non-invasive prenatal testing for identifying and managing high-risk pregnancies

Non-invasive prenatal testing is regularly used to screen for aneuploidies and Rhesus status of a fetus. Since 1997 when free fetal DNA (ffDNA) in the maternal circulation was first identified, it has been hypothesized that it may be possible to use non-invasive prenatal testing (NIPT) to identify high-risk pregnancies including pre-eclampsia, growth restriction and preterm birth. Since then there has been much interest in this area as a way to identify and understand disease processes. This review presents the current evidence for this approach. For pre-eclampsia the hypothesis is that ffDNA would increase but the evidence for this is heterogenous across studies and trimesters. There is however increasing agreement between studies that by the third trimester ffDNA is more likely to be raised in pre-eclamptic patients than controls. For preterm birth, again, the main hypothesis is that ffDNA should increase. The results are also heterogenous, with some studies finding increased ffDNA prior to preterm birth, and others finding no change. For fetal growth restriction, there are competing theories for reduced and increased ffDNA and some studies suggest that levels are raised and some reduced. There are complexities in interpreting all of this evidence as the studies' designs, patient populations, and especially in the context of growth restriction, the definitions are not clear. Furthermore, authors use different biochemical tests and different units to describe their results, making meta-analysis difficult. All of these issues and conflicting findings lead us to the conclusion that currently there is yet no definitive place in clinical practice for NIPT to support the diagnosis and management of high-risk pregnancies. However, it is vital that this research continues as it could open the door to better understanding of the disease process and novel approaches to management.

Maternal total cell-free DNA in preeclampsia with and without intrauterine growth restriction

Elevation of total cell-free DNA (cfDNA) in patients with preeclampsia is well-known; however, whether this change precedes the onset of symptoms remains inconclusive. Here, we conducted a nested case-control study to determine the elevation of cfDNA levels in women who subsequently developed preeclampsia. Methylated HYP2 (m-HYP2) levels were determined in 68 blood samples collected from women with hypertensive disorders of pregnancy, along with 136 control samples, using real-time quantitative PCR. The measured m-HYP2 levels were converted to multiples of the median (MoM) values for correction of maternal characteristics. The m-HYP2 levels and MoM values in patients with preeclampsia were significantly higher than in controls during the third trimester (P < 0.001, both), whereas those for women who subsequently developed preeclampsia did not differ during the second trimester. However, when patients with preeclampsia were divided based on the onset-time of preeclampsia or 10th percentile birth weight, both values were significantly higher in women who subsequently developed early-onset preeclampsia (P < 0.05, both) and preeclampsia with small-for-gestational-age (SGA) neonate (P < 0.01, both) than controls. These results suggested that total cfDNA levels could be used to predict early-onset preeclampsia or preeclampsia with SGA neonate.

The effect of antithrombotic therapy on the recurrence of placenta-mediated diseases in pregnancy

Objectives: To analyze the recurrence rate of placenta-mediated diseases (PMDs) such as preeclampsia (PE) and/or intrauterine growth restriction (IUGR), intrauterine fetal death (IUFD), and placental abruption (PA) in high-risk patients on antithrombotic therapy (AT) because of a previous obstetrical history for such complications.Methods: The study group (SG) included 150 patients to whom either 100 mg of aspirin or low-molecular weight heparin (LMWH) was administered due to a previous history of PMDs. The AT in the SG was started before 16 gestational weeks (g.w.). The patients in the first control group (CG-1) were 150 who also had a previous obstetrical history of PMDs, but did not receive antithrombotic therapy (AT) throughout their ongoing pregnancies. The second CG (CG-2) comprised 320 patients with a previous history of normally developing pregnancies and without AT throughout their ongoing pregnancies.Results: The total percentage of PE in pregnant patients from the SG was 25.3% (38/150 patients), with 22.2% (10/45) in the SG on AT only with LDA (SG-LDA group), 25% (17/68) in the SG on AT only with LMWHs (SG-LMWH group) and 29.7% (11/37) in the SG on combined AT with LDA and LMWHs (SG-LDA + LMWH group), as opposed to 18.67% (28/150) in CG-1 and 0.62% (2/320) in CG-2. The recurrent severe PE/total PE ratio in the SG was 44.7% (17/38), with 30% (3/10) in the SG-LDA group, 47% (8/17) in the SG-LMWH group and 54% (6/11) in the SG-LDA + LMWH group, against 75% (21/28) in CG-1. There were no cases with severe PE in CG-2. All cases with recurrent IUGR from the SG were equal to 13.3% (20/150), with 13.3% (6/45) in the SG-LDA group, 11.76% (8/68) in the SG-LMWH group and 16.2% (6/37) in the SG-LDA + LMWH group, as compared to 30% (45/150) in CG-1 and 5% (16/320) in CG-2. As a whole, the overall recurrence rate of PMDs in the SG was 38.67% (58/150), with 35.56% (16/45) in the SG-LDA group, 36.76% (25/68) in the SG-LMWH group and 45.9% (17/37) in the SG-LDA + LMWH group, as compared to 50.67% (76/150) in CG-1 and 5.94% (19/320) in CG-2.Conclusion: AT had a partial beneficial effect on the prophylaxis of recurrent PMDs. On the one hand, AT led to a significant reduction in the recurrent severe PE/total PE ratio, as well as in the total PMDs' recurrence rate in the SG as compared to the one in CG-1. On the other hand, the percentage of recurrent PMDs still remained significantly higher in the SG as compared to CG-2. Pregnant patients with previous PMDs still need close surveillance in subsequent pregnancies as they remain at a high risk for complications.

Novel Epigenetic Biomarkers in Pregnancy-Related Disorders and Cancers

As the majority of cancers and gestational diseases are prognostically stage- and grade-dependent, the ultimate goal of ongoing studies in precision medicine is to provide early and timely diagnosis of such disorders. These studies have enabled the development of various new diagnostic biomarkers, such as free circulating nucleic acids, and detection of their epigenetic changes. Recently, extracellular vesicles including exosomes, microvesicles, oncosomes, and apoptotic bodies have been recognized as powerful diagnostic tools. Extracellular vesicles carry specific proteins, lipids, DNAs, mRNAs, and miRNAs of the cells that produced them, thus reflecting the function of these cells. It is believed that exosomes, in particular, may be the optimal biomarkers of pathological pregnancies and cancers, especially those that are frequently diagnosed at an advanced stage, such as ovarian cancer. In the present review, we survey and critically appraise novel epigenetic biomarkers related to free circulating nucleic acids and extracellular vesicles, focusing especially on their status in trophoblasts (pregnancy) and neoplastic cells (cancers).

Extracellular DNA in the Dynamics of Uncomplicated Pregnancy

We analyzed the concentration of extracellular DNA and its fractions in the dynamics of uncomplicated pregnancy Thirty women with singleton pregnancy were examined. The concentration of total, maternal, and fetal cell-free DNA in maternal blood was measured at gestation weeks 11-14, 24-26, and 30-32. The level of total cell-free DNA was evaluated by measuring the concentration of RASSF1A gene using quantitative PCR analysis, the level of cell-free fetal DNA was assessed by determining the hypermethylated part of RASSF1A gene. The concentration of total cell-free DNA and cell-free maternal DNA did not change during the first half of pregnancy, but increased after 24-26 weeks. The level of cell-free fetal DNA increased from the first to the second and third trimester: 14.15 (2.32-36.25), 24.87 (6.29-129.32), and 32.62 (8.97-133.52) GE/ml (p<0.05), respectively. Our results characterize the dynamics of the content of cell-free DNA and its fractions during pregnancy, which should be taken into account when using cell-free DNA for prediction of placenta-associated complications.

RASSF1A uncouples Wnt from Hippo signalling and promotes YAP mediated differentiation via p73

Transition from pluripotency to differentiation is a pivotal yet poorly understood developmental step. Here, we show that the tumour suppressor RASSF1A is a key player driving the early specification of cell fate. RASSF1A acts as a natural barrier to stem cell self-renewal and iPS cell generation, by switching YAP from an integral component in the β-catenin-TCF pluripotency network to a key factor that promotes differentiation. We demonstrate that epigenetic regulation of the Rassf1A promoter maintains stemness by allowing a quaternary association of YAP-TEAD and β-catenin-TCF3 complexes on the Oct4 distal enhancer. However, during differentiation, promoter demethylation allows GATA1-mediated RASSF1A expression which prevents YAP from contributing to the TEAD/β-catenin-TCF3 complex. Simultaneously, we find that RASSF1A promotes a YAP-p73 transcriptional programme that enables differentiation. Together, our findings demonstrate that RASSF1A mediates transcription factor selection of YAP in stem cells, thereby acting as a functional "switch" between pluripotency and initiation of differentiation.

Association of Placenta Previa with a History of Previous Cesarian Deliveries and Indications for a Possible Role of a Genetic Component

A prior Cesaria section (C-section) is an important risk factor that leads to endometrial damage and abnormal implantation of the placenta. Our retrospective study aims to correlate the frequency of placenta previa to previous C-sections, to determine the effect of male gender in this condition and to evaluate further the maternal outcome. Seventy-six cases with placenta previa were selected out of 5200 live births. Diagnosis was confirmed by ultrasound and in the operating theater. In the 76 women examined, we found 50 cases with a history of a previous C-section (66.0%) and 49 male offspring (65.0%) (p <0.001), with a mean birth weight of 2635 ± 740 g. Of all these patients, six (8.0%) cases developed placenta percreta, seven (9.0%) were transferred to the intensive care unit (ICU), 14 (18.0%) women needed blood transfusion and eight (11.0%) underwent hysterectomy. The results of our series show a strong correlation of placenta previa to a history of previous C-sections and a predominance of male fetuses. Early recognition and proper monitoring could minimize the possibility of a poor outcome.

Steroidogenic factor-1 hypermethylation in maternal rat blood could serve as a biomarker for intrauterine growth retardation

Intrauterine growth retardation (IUGR) is a common obstetric complication lacking an optimal method for prenatal screening. DNA methylation profile in maternal blood holds significant promise for prenatal screening. Here, we aimed to screen out potential IUGR biomarkers in maternal blood from the perspective of DNA methylation. The IUGR rat model was established by prenatal maternal undernutrition. High-throughput bisulfite sequencing of genomic DNA methylation followed by functional clustering analysis for differentially methylated region (DMR)-associated genes demonstrated that genes regulating transcription had the most significantly changed DNA methylation status in maternal blood with IUGR. Genes about apoptosis and placental development were also changed. Besides increased placental apoptosis, IUGR rats demonstrated the same hypermethylated CpG sites of steroidogenic factor-1 (SF-1, a DMR-associated transcription factor about placenta) promoter in maternal blood and placentae. Further, ff1b, the SF-1 ortholog, was knocked out in zebrafish by CRISPR/Cas9 technology. The knock-out zebrafish demonstrated developmental inhibition and increased IUGR rates, which confirmed the role of SF-1 in IUGR development. Finally, hypermethylated SF-1 was observed in human maternal blood of IUGR. This study firstly presented distinct DNA methylation profile in maternal blood of IUGR and showed hypermethylated SF-1 could be a potential IUGR biomarker in maternal rat blood.

Intrauterine growth retardation-associated syncytin b hypermethylation in maternal rat blood revealed by DNA methylation array analysis

BackgroundEmerging evidence suggests that DNA methylation in maternal blood is a promising target for intrauterine growth retardation (IUGR) screening, a common developmental toxicity. Here, we aimed to screen out IUGR-related DNA methylation status in maternal blood via high-throughput profiling.MethodsPregnant Wistar rats were subcutaneously administered nicotine (1 mg/kg) twice per day from gestational day (GD) 11 to GD20 to establish the IUGR model. MeDIP array assays and the following GO analysis were used to evaluate DNA methylation status in maternal blood. One placental development-associated gene was selected for further confirmation.ResultsGenes regulating the development of multiple organs and major body systems had changed DNA methylation frequencies in the maternal blood of IUGR rats. Placental development, which can affect the development of multiple fetal organs and induce IUGR, is a hypermethylated cluster consisting of four significantly changed genes, including syncytin b (Synb), Lrrc15, Met, and Tex19.1. With the most significant change, Synb hypermethylation in maternal blood was confirmed by bisulfite-sequencing PCR (BSP). Moreover, decreased Synb expression and histological changes were observed in IUGR placentae.ConclusionThe IUGR-associated DNA methylation profile in maternal blood, such as placenta-related Synb hypermethylation, provides evidence for further studies on possible IUGR biomarkers.

Evaluation of fetal hypermethylated RASSF1A in pre-eclampsia and its relationship with placental protein-13, pregnancy associated plasma protein-A and urine protein

OBJECTIVES

Cell free fetal DNA (cffDNA) and its hypermethylated RASSF1A gene signify a recent advancement in non-invasive prenatal diagnosis of feto-placental anomalies like pre-eclampsia. The study uses hypermethylated RASSF1A gene to quantify cffDNA and to assess its relationship with placental and urine proteins in pre-eclampsia cases.

DESIGN AND METHODS

DNA was isolated from plasma samples of clinically diagnosed cases of pre-eclampsia (n=103) and normal pregnancy (n=616) from 21weeks of gestation. Through methylation sensitive enzyme (BstUI) digestion; followed by real time-polymerase chain reaction (RT-PCR), quantification of hypermethylated RASSF1A was done. Immunoassays determined: placental protein-13 (pp-13) and pregnancy associated plasma protein A (PAPP-A) and pyrogallol red molybdate assay for 24h urine protein.

RESULTS

Highly significant differences between control and pre-eclampsia cases for hypermethylated RASSF1A concentrations were found; Group I: 33±7.35 vs 74.46±16.71, Group II: 53.75±16.65 vs 244.22±35.68, Group III: 93.25±19.08 vs 412.31±80.18, Group IV: 144.30±18.13 vs 1056.89±153.78, Group V: 307.55±40.76 vs 2763.76±259.76copies/ml. Multivariate Pearson's correlation analysis of hypermethylated RASSF1A with pp-13, PAPP-A and urine proteins showed positive and very highly significant (P<0.001) associations.

CONCLUSIONS

Diagnostic potential of fetal specific, hypermethylated RASSF1A was evaluated. Its positive relationship with placental and urine proteins submit the case for considering it as a reliable marker for pre-eclampsia.

Fetal-specific hypermethylated RASSF1A quantification in pregnancy

OBJECTIVE

To quantify cell free fetal DNA (cffDNA) with fetal specific epigenetic marker, hypermethylated RASSF1A, in maternal plasma of normal pregnant women from 20 weeks of gestation and to assess its relationship with maternal age, height, pre-pregnancy weight and body mass index (BMI).

METHODS

Hundred normal pregnant women within the gestational age of 21-40 weeks were randomly selected and grouped into five (n = 20). Group 1: 21-24, Group 2: 25-28, Group 3: 29-32, Group 4: 33-36 and Group 5: 37-40 weeks. Maternal plasma DNA was extracted, digested with methylation-sensitive restriction enzyme, BstUI and the fetal specific DNA (cffDNA) was quantified by Real-time polymerase chain reaction (qRT-PCR).

RESULTS

The mean hypermethylated RASSF1A concentrations in different gestational groups were Group 1: 30.1 ± 14.9, Group 2: 52.6 ± 22.18, Group 3: 93.2 ± 19.08, Group 4: 172.8 ± 26.81 and Group 5: 337.8 ± 52.9 copies/ml. Pearson's correlation analysis showed highly significant positive correlation between cffDNA and gestational age (r = 0.899, p < 0.001). BMI was also found to be positively related to cffDNA (r = 0.217, p < 0.05). However, it did not show any correlation with maternal age, height and pre-pregnancy weight.

CONCLUSIONS

The gestational age-dependent increase of hypermethylated RASSF1A; the fetal specific epigenetic marker in maternal plasma was demonstrated, in an Indian study group of normal pregnant women. Findings would form the basis of future studies involving pregnancy complications that would aid in the early diagnosis of placental pathologies with hypermethylated RASSF1A.

Early Prediction of Hypertensive Disorders of Pregnancy Using Cell-Free Fetal DNA, Cell-Free Total DNA, and Biochemical Markers

OBJECTIVE

To evaluate the predictive value of separate and combined tests using cell-free fetal DNA (cffDNA), cell-free total DNA (cfDNA), and biochemical markers for the early detection of pregnancies with hypertensive disorders.

METHODS

A nested case-control study was conducted with 135 singleton pregnancies including 17 gestational hypertension cases, 34 preeclampsia (PE) cases, and 84 controls. We performed real-time quantitative PCR to measure levels of DSCR3 and RASSF1A as cffDNA markers and HYP2 as a cfDNA marker in the first and early second trimesters. Levels of pregnancy-associated plasma protein A (PAPP-A), α-fetoprotein, β-human chorionic gonadotropin, unconjugated estriol, and inhibin A were also determined.

RESULTS

Compared with controls, the median levels and multiples of the median (MoM) values of HYP2 were significantly higher in the PE and hypertensive disorders of pregnancy (HDP) groups at 6-14 and 15-23 weeks. Frist-trimester PAPP-A MoM was significantly lower in PE and HDP than in controls. For PE and HDP, the best model included the first-trimester DSCR3, HYP2, and PAPP-A MoM values achieving detection rates of 67 and 58% at a fixed 10% false-positive rate, respectively [area under the receiver operating characteristic curve 0.832 (95% CI 0.689-0.928) for PE; 0.751 (0.607-0.863) for HDP].

DISCUSSION

The study demonstrates the potential utility of combined first-trimester cffDNA, cfDNA, and PAPP-A for the early prediction of PE.

Quantification and Application of Potential Epigenetic Markers in Maternal Plasma of Pregnancies with Hypertensive Disorders

The aim of this study was to evaluate quantitative aberrations of novel fetal-specific epigenetic markers in maternal plasma of pregnancies with hypertensive disorders. We compared the concentrations of DSCR3, RASSF1A, and SRY as cell-free fetal DNA markers in 188 normal pregnancies, 16 pregnancies with early-onset preeclampsia (EO-PE), 47 pregnancies with late-onset preeclampsia (LO-PE), and 29 pregnancies with gestational hypertension (GH). The concentrations of all markers were significantly correlated with gestational age (p < 0.001 for all). Strong positive correlations were also observed between DSCR3 and SRY (r = 0.471, p < 0.001), as well as between RASSF1A and SRY (r = 0.326, p = 0.015) and between DSCR3 and RASSF1A (r = 0.673, p < 0.001). The concentrations of DSCR3 and RASSF1A in the EO-PE were significantly higher at 24–32 weeks and onwards (p < 0.05 for both). In the LO-PE, DSCR3 and RASSF1A concentrations were significantly higher only at 33–41 weeks compared with the controls. The concentrations of all markers in the GH group were not significantly different from those in the control group. This study is the first demonstration that DSCR3 is a novel epigenetic marker that can be an alternative to the RASSF1A for the prediction of EO-PE.

Potential role of folate in pre-eclampsia

Dietary deficiencies of folate and other B vitamin cofactors involved in one-carbon metabolism, together with genetic polymorphisms in key folate-methionine metabolic pathway enzymes, are associated with increases in circulating plasma homocysteine, reduction in DNA methylation patterns, and genome instability events. All of these biomarkers have also been associated with pre-eclampsia. The aim of this review was to explore the literature and identify potential knowledge gaps in relation to the role of folate at the genomic level in either the etiology or the prevention of pre-eclampsia. A systematic search strategy was designed to identify citations in electronic databases for the following terms: folic acid supplementation AND pre-eclampsia, folic acid supplementation AND genome stability, folate AND genome stability AND pre-eclampsia, folic acid supplementation AND DNA methylation, and folate AND DNA methylation AND pre-eclampsia. Forty-three articles were selected according to predefined selection criteria. The studies included in the present review were not homogeneous, which made pooled analysis of the data very difficult. The present review highlights associations between folate deficiency and certain biomarkers observed in various tissues of women at risk of pre-eclampsia. Further investigation is required to understand the role of folate in either the etiology or the prevention of pre-eclampsia.

Rapid method for growth hormone receptor exon 3 delete (GHRd3) SNP genotyping from archival human placental samples

Analysis of archival samples from cohorts of pregnant women may be key to discovering prognosticators of stillbirth and pregnancy/perinatal complications. Growth hormone (GH) and its receptor (GHR) are pivotal in feto-placental development and pregnancy maintenance. We report a rapid, optimized method for genotyping the GHR full-length versus exon 3-deleted isoform (GHRd3). TaqMan single nucleotide polymorphism (SNP) genotyping proved superior to standard multiplex polymerase chain reaction (PCR) in allele detection and GHR genotyping from archived samples, including those with poor genomic deoxyribonucleic acid quality/quantity such as formalin fixed, paraffin embedded, blood, and serum. Furthermore, this assay is suitable for high through put 96 or 384-well plate quantitative PCR machines with automated genotype calling software. The TaqMan genotyping assay can increase the data obtained from precious archival human samples.

Prospective evaluation of RASSF1A cell-free DNA as a biomarker of pre-eclampsia

INTRODUCTION

This study aims to quantify total and fetal cell-free DNA (cfDNA) in maternal plasma at different gestational ages and to assess whether this could represent a reliable predictive marker of pre-eclampsia (PE) before clinical onset.

METHODS

We performed a qPCR assay to compare the cfDNA concentration of hypermethylated and unmethylated RASSF1A promoter gene sequences in maternal plasma among 3 groups of pregnant women. These included 17 women with overt PE, 33 women at risk for the disease subsequently differentiated into 9 who developed PE and 24 who did not, and 73 controls. All women at risk were consecutively sampled throughout the whole gestation.

RESULTS

Both total and fetal cfDNA had a good diagnostic performance in distinguishing patients with overt PE from healthy controls. When comparing women at risk who developed PE to women at risk who did not, the predictive capability was satisfactory at a gestational age ranging from 17 to 30 weeks. This allowed establishing within this time interval a cut-off value of 735 GE/ml for total cfDNA (87.5% sensitivity and 70.0% specificity), and a cut-off value of 7.49 GE/ml for fetal cfDNA (100% sensitivity and 50% specificity). cfDNA levels turned positive several weeks before the onset of the disease: from 2 to 18 weeks for total cfDNA and from 8 to 17 weeks for fetal cfDNA.

DISCUSSION

The simultaneous use of total and fetal cfDNA would allow an accurate monitoring and prevention of PE development thus suggesting that RASSF1A could represent a potential biomarker of PE.

Quantification of the placental epigenetic signature of the SERPINB5 gene in maternal plasma of pregnancies complicated by small for gestational age

INTRODUCTION

To investigate the association between pregnancies with small for gestational age (SGA) neonates and the concentration of cell-free fetal DNA or cell-free total DNA in maternal plasma during the first and second trimesters using tissue-specific epigenetic characteristics of the SERPINB5 gene.

METHODS

A nested case-control study was conducted with maternal plasma collected at 11 to 26 gestational weeks from 51 women with SGA neonates and 102 controls. We performed a real-time quantitative methylation-specific PCR to quantify concentrations of unmethylated-SERPINB5 (U-SERPINB5) as a cell-free fetal DNA marker and methylated-SERPINB5 (M-SERPINB5) as a cell-free total DNA marker.

RESULTS

A positive correlation was observed between U-SERPINB5 and M-SERPINB5 concentrations in both control (r = 0.363, p < 0.001) and SGA groups (r = 0.548, p < 0.001). Moreover, the concentration of U-SERPINB5 or M-SERPINB5 was significantly positive correlated with gestational age at sampling in both controls (U-SERPINB5: r = 0.397, p < 0.001; M-SERPINB5: r = 0.275, p = 0.005) and SGA (U-SERPINB5: r = 0.274, p = 0.052; M-SERPINB5: r = 0.439, p = 0.001). However, the concentration of U-SERPINB5 or M-SERPINB5 was not correlated with birthweight. At 11-14 weeks, U-SERPINB5 and M-SERPINB5 concentrations in SGA did not differ significantly from those of controls. There were also no statistically significant differences in the concentrations of U-SERPINB5 and M-SERPINB5 between SGA and controls at 15-26 weeks of gestation.

DISCUSSION

Our findings suggest that U-SERPINB5 and M-SERPINB5 concentrations in maternal plasma during early pregnancy are not associated with pregnancies who delivered SGA neonates.

Cell-free fetal DNA and pregnancy-related complications (review)

Cell-free fetal DNA (cff-DNA) is a novel promising biomarker that has been applied in various aspects of obstetrical research, notably in prenatal diagnosis and complicated pregnancies. It is easily detected by semi-quantitative PCR for the SRY target gene. It is well recognized that the levels of circulating cff-DNA play a role in various complications of pregnancy. In this review, we explore the implications of the detection of cff-DNA in a range of pregnancy-related complications, such as preeclampsia, intrauterine growth restriction (IUGR), preterm labor, placenta previa and hyperemesis gravidarum. cff-DNA is released due to apoptotic mechanisms occurring on trophoblastic cells, although recent in vivo studies support the existence of additional mechanisms. The increase in the levels of cff-DNA can be used to predict pregnancy-related complications and has great value in the field of prenatal diagnosis and in common pregnancy-related complications, as it precedes the clinical symptoms of the disease. Gestational age is a factor that determines the elevation in cff-DNA levels in response to pathological conditions. In conclusion, the detection of cff-DNA levels has a number of valuable applications in prenatal screening; however, the detection of cff-DNA levels has not yet been applied in clinical practice for the diagnosis of pregnancy-related disorders. Thus, studies are focusing on unraveling the etiology of alterations in its levels under pathological conditions during pregnancy, in order to determine the potenial predictive and diagnostic applications of this biomarker.

Role of fetal DNA in preeclampsia (review)

Preeclampsia is an autoimmune disorder characterized by hypertension. It begins with abnormal cytotrophoblast apoptosis, which leads to inflammation and an increase in the levels of anti-angiogenic factors followed by the disruption of the angiogenic status. Increased levels of fetal DNA and RNA coming from the placenta, one of the most commonly affected organs in pregnancies complicated by preeclampsia, have been found in pregnant women with the condition. However, it remains unknown as to whether this is a cause or a consequence of preeclampsia. Few studies have been carried out on preeclampsia in which an animal model of preeclampsia was induced by an injection of different types of DNA that are mimic fetal DNA and provoke inflammation through Toll-like receptor 9 (TLR9) or cyclic guanosine monophosphate-adenosine monophosphate (cGAMP). The specific mechanisms involved in the development of preeclampsia are not yet fully understood. It is hypothesized that the presence of different fragments of fetal DNA in maternal plasma may cause for the development of preeclampsia. The function of DNase during preeclampsia also remains unresolved. Studies have suggested that its activity is decreased or the DNA is protected against its effects. Further research is required to uncover the pathogenesis of preeclampsia and focus more on the condition of patients with the condition.

Can the quantity of cell-free fetal DNA predict preeclampsia: a systematic review

OBJECTIVE

Previous studies have demonstrated an increase in the quantity of cell-free fetal DNA (cffDNA) before the onset of preeclampsia. It would be beneficial if the quantity of cffDNA predicted preeclampsia in order to implement preventative trials and strategies to decrease maternal and fetal morbidity. Our objective was to review the literature on using cffDNA levels as a predictor of preeclampsia.

METHODS

We performed a systematic review following the Meta-analyses and Systematic Review of Observational Studies guidelines. Included studies evaluated cffDNA levels in pregnant women before the clinical onset of preeclampsia.

RESULTS

Thirteen studies met inclusion criteria. There was considerable heterogeneity between included studies, and all received a quality grade of C on the Grading of Recommendations Assessment, Development, and Evaluation scale. Of the 13 studies, 11 found an increase in cffDNA among pregnant women who subsequently developed preeclampsia. In addition, all four studies analyzing early-onset or severe preeclampsia found significantly elevated cffDNA levels prior to disease onset.

CONCLUSION

Cell-free fetal DNA quantification is a promising marker for preeclampsia prediction, especially for the development of early-onset or severe preeclampsia. However, because of the heterogeneity in published studies, a precise conclusion about the statistical and clinical relevance cannot be made.