Circulating predictive biomarkers in preeclampsia

AI-based preeclampsia detection and prediction with electrocardiogram data

Introduction

More than 76,000 women die yearly from preeclampsia and hypertensive disorders of pregnancy. Early diagnosis and management of preeclampsia can improve outcomes for both mother and baby. In this study, we developed artificial intelligence models to detect and predict preeclampsia from electrocardiograms (ECGs) in point-of-care settings.

Methods

Ten-second 12-lead ECG data was obtained from two large health care settings: University of Tennessee Health Science Center (UTHSC) and Atrium Health Wake Forest Baptist (AHWFB). UTHSC data was split into 80% training and 20% holdout data. The model used a modified ResNet convolutional neural network, taking one-dimensional raw ECG signals comprising 12 channels as an input, to predict risk of preeclampsia. Sub-analyses were performed to assess the predictive accuracy for preeclampsia prediction within 30, 60, or 90 days before diagnosis.

Results

The UTHSC cohort included 904 ECGs from 759 females (78.8% African American) with a mean ± sd age of 27.3 ± 5.0 years. The AHWFB cohort included 817 ECGs from 141 females (45.4 African American) with a mean ± sd age of 27.4 ± 5.9 years. The cross-validated ECG-AI model yielded an AUC (95% CI) of 0.85 (0.77-0.93) on UTHSC holdout data, and an AUC (95% CI) of 0.81 (0.77-0.84) on AHWFB data. The sub-analysis of different time windows before preeclampsia prediction resulted in AUCs (95% CI) of 0.92 (0.84-1.00), 0.89 (0.81-0.98) and 0.90 (0.81-0.98) when tested on ECGs 30 days, 60 days and 90 days, respectively, before diagnosis. When assessed on early onset preeclampsia (preeclampsia diagnosed at <34 weeks of pregnancy), the model's AUC (95% CI) was 0.98 (0.89-1.00).

Discussion

We conclude that preeclampsia can be identified with high accuracy via application of AI models to ECG data.

Longitudinal Associations between Ambient Air Pollution and Angiogenic Biomarkers among Pregnant Women in the LIFECODES Study, 2006-2008

BACKGROUND

Exposures to ambient air pollution during pregnancy have been linked to adverse pregnancy outcomes such as preeclampsia and fetal growth restriction. Although evidence has shown that women with preeclampsia have higher ratio of soluble fms-like tyrosine kinase 1 to placental growth factor (sFlt-1/PlGF ratio), the potential impact of air pollution on markers of placental growth and function has not been well studied.

OBJECTIVES

We aimed to examine longitudinal associations between ambient air pollution exposure and angiogenic factors among pregnant women in LIFECODES, a prospective birth cohort and biorepository in Massachusetts in the United States.

METHODS

PlGF and sFlt-1 were measured among pregnant women using plasma samples collected around 10, 18, 26, and 35 wk' gestation. Women's exposures to ozone (O 3 ), fine particulate matter with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ), and nitrogen dioxide (NO 2 ) within 1, 2, 4, and 8 wk prior to each plasma sample collection were estimated based on geocoded residential addresses, and mixed effect linear regression models were fitted to assess their associations with sFlt-1/PlGF ratio, sFlt-1 (ng/mL), and PlGF (pg/mL). Percent changes in outcomes associated with each interquartile range increase in exposures were reported, along with their 95% confidence intervals.

RESULTS

A total of 1,066 pregnant women were included. In the multipollutant models, significant associations were observed for increased sFlt-1/PlGF ratio (PM 2.5 3-8 wk' gestation, NO 2 : 35-39 wk' gestation), elevated sFlt-1 (O 3 : 26-34 wk' gestation, PM 2.5 : 3-8 wk' gestation), decreased sFlt-1 (NO 2 : 4-8 wk' gestation), and decreased PlGF (NO 2 : 34-39 wk' gestation) after adjusting for sociodemographic status, smoking, drinking, body mass index, parity, history of chronic hypertension, and conception time.

DISCUSSION

Exposures to PM 2.5 during early pregnancy and exposures to O 3 and NO 2 during late pregnancy were associated with increased sFlt-1/PlGF ratio, elevated sFlt-1 and with decreased PlGF, which may be a potential mechanism underlying ambient air pollution's impacts on adverse pregnancy and birth outcomes. https://doi.org/10.1289/EHP11909.

Elevated Placental microRNA-155 Is a Biomarker of a Preeclamptic Subtype

BACKGROUND

Preeclampsia is a complicated syndrome with marked heterogeneity. The biomarker-based classification for this syndrome is more constructive to the targeted prevention and treatment of preeclampsia. It has been reported that preeclamptic patients had elevated microRNA-155 (miR-155) in placentas or circulation. Here, we investigated the characteristics of patients with high placental miR-155 (pl-miR-155).

METHODS

Based on the 95th percentile (P95) of pl-miR-155 in controls, preeclamptic patients were divided into high miR-155 group (≥P95) and normal miR-155 group (<P95). The changes of placental pathology, clinical manifestations, and placental transcriptome of preeclamptic patients were clustered by t-distributed stochastic neighbor embedding and hierarchical clustering analysis. The placental restricted miR-155 overexpression mouse model was constructed, and the phenotype, placental pathology, and transcriptome were evaluated. Furthermore, the therapeutic potential of antagonist of miR-155 was explored by administrating with antagomir-155.

RESULTS

About one-third of preeclamptic patients had high pl-miR-155 expression, which was positively correlated with circulating miR-155 levels. These patients could be clustered as 1 group, according to clinical manifestation, placental pathology, or transcriptomes by t-distributed stochastic neighbor embedding and hierarchical clustering analysis. Further, the pregnant mice with placental restricted miR-155 overexpression could simulate the changes of clinical signs, pathology, and transcriptome of placentas in patients with high pl-miR-155. AntagomiR-155 treatment relieved the preeclampsia-like phenotype and improved the placental vascular development in mice.

CONCLUSIONS

There is at least 1 type of preeclampsia with upregulated miR-155 presenting more severe clinical manifestations. MiR-155 may be a potential therapeutic target in patients with high pl-miR-155.

Metabolomics in Prenatal Medicine: A Review

Pregnancy is a complicated and insidious state with various aspects to consider, including the well-being of the mother and child. Developing better non-invasive tests that cover a broader range of disorders with lower false-positive rates is a fundamental necessity in the prenatal medicine field, and, in this sense, the application of metabolomics could be extremely useful. Metabolomics measures and analyses the products of cellular biochemistry. As a biomarker discovery tool, the integrated holistic approach of metabolomics can yield new diagnostic or therapeutic approaches. In this review, we identify and summarize prenatal metabolomics studies and identify themes and controversies. We conducted a comprehensive search of PubMed and Google Scholar for all publications through January 2020 using combinations of the following keywords: nuclear magnetic resonance, mass spectrometry, metabolic profiling, prenatal diagnosis, pregnancy, chromosomal or aneuploidy, pre-eclampsia, fetal growth restriction, pre-term labor, and congenital defect. Metabolite detection with high throughput systems aided by advanced bioinformatics and network analysis allowed for the identification of new potential prenatal biomarkers and therapeutic targets. We took into consideration the scientific papers issued between the years 2000-2020, thus observing that the larger number of them were mainly published in the last 10 years. Initial small metabolomics studies in perinatology suggest that previously unidentified biochemical pathways and predictive biomarkers may be clinically useful. Although the scientific community is considering metabolomics with increasing attention for the study of prenatal medicine as well, more in-depth studies would be useful in order to advance toward the clinic world as the obtained results appear to be still preliminary. Employing metabolomics approaches to understand fetal and perinatal pathophysiology requires further research with larger sample sizes and rigorous testing of pilot studies using various omics and traditional hypothesis-driven experimental approaches.

Association of Aquaporin-3, Aquaporin-7, NOS3 and CYBA polymorphisms with hypertensive disorders in women

Preeclampsia (PE), a pregnancy disorder influenced by oxidative stress and hypoxia, affects the health of the mother and baby and is associated with an increased risk of future hypertension (HT). Aquaporins are a family of water channels, comprising members that also transport glycerol (aquaglyceroporins) and hydrogen peroxide (peroxiporins), key molecules for metabolic homeostasis and redox signaling. Here, we investigated the association of Aquaporin-3 (AQP3; rs2231231), Aquaporin-7 (AQP7; rs2989924), NOS3 (4B/A intron) and CYBA (rs4673) genetic polymorphisms with the development of hypertensive disorders by qPCR/PCR in a cohort of 150 normotensive (NT) women (N = 90) or with previous PE (N = 60) during pregnancy. Prospectively, women were reclassified 2-16 years after pregnancy as NT (N = 98) or hypertensive (N = 48) and the genetic associations were reevaluated. In addition, genetic associations were reevaluated and compared between normotensive and hypertensive (HT) subjects. We found that AQP3 rs2231231, an aquaglyceroporin/peroxiporin, is associated with the development of HT, whereas AQP7, NOS3 and CYBA polymorphism did not correlate with PE or future HT. Because AQP3 was associated with hypertension only after pregnancy, its role might be related to later risk factors of hypertension such as metabolic syndrome or oxidative stress.

Biosensors for Detection of Human Placental Pathologies: A Review of Emerging Technologies and Current Trends

Substantial growth in the biosensor research has enabled novel, sensitive and point-of-care diagnosis of human diseases in the last decade. This paper presents an overview of the research in the field of biosensors that can potentially predict and diagnosis of common placental pathologies. A survey of biomarkers in maternal circulation and their characterization methods is presented, including markers of oxidative stress, angiogenic factors, placental debris, and inflammatory biomarkers that are associated with various pathophysiological processes in the context of pregnancy complications. Novel biosensors enabled by microfluidics technology and nanomaterials is then reviewed. Representative designs of plasmonic and electrochemical biosensors for highly sensitive and multiplexed detection of biomarkers, as well as on-chip sample preparation and sensing for automatic biomarker detection are illustrated. New trends in organ-on-a-chip based placental disease models are highlighted to illustrate the capability of these in vitro disease models in better understanding the complex pathophysiological processes, including mass transfer across the placental barrier, oxidative stress, inflammation, and malaria infection. Biosensor technologies that can be potentially embedded in the placental models for real time, label-free monitoring of these processes and events are suggested. Merger of cell culture in microfluidics and biosensing can provide significant potential for new developments in advanced placental models, and tools for diagnosis, drug screening and efficacy testing.

Copeptin in Preeclampsia Development

Background:

Preeclampsia complicates 2-8% of all pregnancies worldwide and is one of the leading causes of maternal and neonatal morbidity and mortality. It occurs after the 20th week of gestation and is characterized by high blood pressure, proteinuria or end-organ disease. The heterogeneous and multi-systemic nature of this disease has led to the elusive pathophysiology which delays timely diagnoses and the clinical treatment of those affected.

Objective:

Despite the extensive investigations surrounding the inclusion of various potential markers for PE prediction, early diagnosis remains unresolved. Quantification of copeptin, a stable component of the arginine vasopressin (AVP) precursor is shown to be relatively reliable in confirming the circulating levels of AVP.

Conclusion:

Elevated copeptin levels confirmed in pregnant women have also provided clinical support for its role in PE development. However, its clinical use in predicting disease severity in early-onset pre-eclampsia has been debatable. This review thus recapitulates the current literature surrounding copeptin and its potential as a risk indicator for PE development.</P>

Application of metabolomics to preeclampsia diagnosis

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

ABBREVIATIONS

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

Significance of Serum Uric Acid in Pregnancy Induced Hypertension

BACKGROUND AND OBJECTIVE

Hypertension is one of the common medical complications of pregnancy and contributes significantly to maternal and perinatal morbidity and mortality. Uric acid (UA) is filtered, reabsorbed and secreted by the kidney. Thus, this study was conducted to assess the serum UA levels in PIH and to evaluate the diagnostic value of serum UA level in PIH.

MATERIALS AND METHODS

This is a hospital based comparative cross-sectional study conducted in BPKIHS. Ninety study participants were included; forty five participants were diagnosed of PIH and forty five in control group after obtaining informed consent from study participants from August 2014 to May 2015. Serum UA was done by Uricase method and serum creatinine was done by Jaffe's alkaline picrate method in cobas c311 autoanalyser. Data were expressed in frequency, percentage, mean ± S.D., median (IQR), and Independent t-test, Mann-Whitney U test were applied. p Value <0.05 is considered to be significant.

RESULTS

Mean serum UA levels was higher in PIH compared to control group (5.46 ± 1.51 vs 4.03 ± 0.69) respectively. ROC curve demonstrated that serum UA showed a superior diagnostic efficiency (Sensitivity - 79.07%, Specificity - 71.19%) compared to creatinine (Sensitivity - 62.75%, Specificity - 27.45%) in PIH respectively.

CONCLUSION

The present study shows that serum UA is significantly raised in PIH compared to the control group. Assessment of uric acid is a convenient and cost-effective method for determination of severity in PIH. Thus, serum uric acid can still be used as prevalent marker for risk assessment in PIH.

Pre-eclampsia: Molecular events to biomarkers

Pre-eclampsia is a hypertensive disorder in pregnancy, which accounts for 10-15% of the maternal and perinatal mortality worldwide. Abnormal placental development and tissue hypoxia are its main etiologic factors. The present diagnostic methods of blood pressure monitoring and renal function evaluation are insufficient in the early detection of pre-eclampsia. Since molecular events portent well ahead of the disease onset, biomarker research for the early diagnosis of pre-eclampsia has recently generated ambitious clinical targets. However, no clinically validated biomarker has so far been reported for the prediction of pre-eclampsia. Therefore, this review takes stock of the current understanding of pre-eclampsia from a molecular biology perspective and critically evaluates the following diagnostic potentials claimed for the biomarkers: placental proteins, angiogenic markers, and cell-free fetal DNA (cffDNA) in maternal circulation. Though the emerging evidences in favor of the fetal-specific epigenetic marker, hypermethylated RASSF1A of cffDNA, are highlighted, it pitches for a broader strategy of 'combination biomarker approach' for the reliable forecasting and triaging of pre-eclampsia.

Placental Growth Factor, Soluble fms-Like Tyrosine Kinase 1, Soluble Endoglin, IL-6, and IL-16 as Biomarkers in Preeclampsia

Preeclampsia (PE), an important cause of maternal and perinatal morbidity and mortality worldwide, is a pregnancy-related disease characterized by hypertension and proteinuria after 20 weeks of gestation. The aim of our study was to find a practical panel of biomarkers useful in early diagnosis of PE. This study was carried out at the Obstetrics and Gynecology Department in Tîrgu Mureș University Hospital, Romania, between January 2014 and July 2015 and included 68 pregnant women (47 preeclamptic women and 21 controls) with gestational age between 16 and 20 weeks at enrollment. The biomarkers PlGF, sFlt-1, sEng, IL-6, and IL-16 were determined by ELISA test. We compared the serum levels of soluble markers analysed in preeclamptic women and controls during the second and third trimesters of pregnancy and we found that the best predictor for PE was PlGF with a sensitivity of 100% at a concentration threshold of 120.16 pg/mL, a diagnosis accuracy of 70.8%, and AUC of 0.684 (p = 0.005). We also estimated the risk for PE according to BMI and we found that pregnant women with weight >90 kg had 7 times higher risk for PE. Second-trimester PlGF serum level may serve as an early biomarker for the diagnosis of PE.

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.

In women with previous pregnancy hypertension, levels of cardiovascular risk biomarkers may be modulated by haptoglobin polymorphism

Preeclampsia (PE) may affect the risk for future cardiovascular disease. Haptoglobin (Hp), an acute phase protein with functional genetic polymorphism, synthesized in the hepatocyte and in many peripheral tissues secondary of oxidative stress of PE, may modulate that risk through the antioxidant, angiogenic, and anti-inflammatory differential effects of their genotypes. We performed a prospective study in 352 women aged 35 ± 5.48 years, which 165 had previous PE, 2 to 16 years ago. We studied demographic, anthropometric, and haemodynamic biomarkers such as C-reactive protein (CRP), myeloperoxidase (MPO), and nitric oxide metabolites (total and nitrites), and others associated with liver function (AST and ALT) and lipid profile (total LDL and cholesterol HDL, non-HDL, and apolipoproteins A and B). Finally, we study the influence of Hp genetic polymorphism on all these biomarkers and as a predisposing factor for PE and its remote cardiovascular disease prognosis. Previously preeclamptic women either hypertensive or normotensive presented significant differences in those risk biomarkers (MPO, nitrites, and ALT), whose variation may be modulated by Hp 1/2 functional genetic polymorphism. The history of PE may be relevant, in association with these biomarkers to the cardiovascular risk in premenopausal women.

Endothelial function and circulating biomarkers are disturbed in women and children after preeclampsia

Preeclampsia is a long-term cardiovascular risk factor for the mother and possibly the offspring. Preeclampsia and cardiovascular diseases share common pathophysiological features, including endothelial dysfunction. We explored whether endothelial function, measured noninvasively, as well as circulating biomarkers reflecting lipid metabolism, angiogenesis, and inflammation, differed in paired mothers and offspring 5 to 8 years after delivery. Twenty-six mother and child pairs after pregnancies complicated by preeclampsia were compared with 17 mother and child pairs after uncomplicated pregnancies. In addition, we assessed whether concentrations of maternal circulating biomarkers at delivery predicted findings 5 to 8 years postpartum. We also included an assessment of early onset preeclampsia and specifically addressed the effects of small for gestational age. Endothelial function was significantly reduced in both mothers and children after preeclampsia when combined with a small-for-gestational-age infant compared with mothers and children after pregnancies without a small-for-gestational-age infant (mothers: P<0.001; children: P<0.05). Postpartum maternal soluble fms-like tyrosine kinase 1 (P=0.05) and high-sensitivity C-reactive protein (P=0.02) were elevated in the preeclampsia group compared with controls. High concentrations of these maternal biomarkers both at delivery and 5 to 8 years postpartum were also more frequent in preeclampsia compared with controls (P<0.05). The novelty of our study is the parallel finding of reduced endothelial function in mother and child pairs 5 to 8 years after small-for-gestational-age preeclamptic pregnancies, accompanied by increased inflammatory and antiangiogenic maternal biomarkers. This finding supports the concept of transgenerational risk of cardiovascular disease after preeclampsia.