Maternal serum soluble endoglin at 30-33 weeks in the prediction of preeclampsia

Potential biomarkers for late-onset and term preeclampsia: A scoping review

Preeclampsia is a progressive, multisystem pregnancy disorder. According to the time of onset or delivery, preeclampsia has been subclassified into early-onset (<34 weeks) and late-onset (≥34 weeks), or preterm (<37 weeks) and term (≥37 weeks). Preterm preeclampsia can be effectively predicted at 11–13 weeks well before onset, and its incidence can be reduced by preventively using low-dose aspirin. However, late-onset and term preeclampsia are more prevalent than early forms and still lack effective predictive and preventive measures. This scoping review aims to systematically identify the evidence of predictive biomarkers reported in late-onset and term preeclampsia. This study was conducted based on the guidance of the Joanna Briggs Institute (JBI) methodology for scoping reviews. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for scoping reviews (PRISMA-ScR) was used to guide the study. The following databases were searched for related studies: PubMed, Web of Science, Scopus, and ProQuest. Search terms contain “preeclampsia,” “late-onset,” “term,” “biomarker,” or “marker,” and other synonyms combined as appropriate using the Boolean operators “AND” and “OR.” The search was restricted to articles published in English from 2012 to August 2022. Publications were selected if study participants were pregnant women and biomarkers were detected in maternal blood or urine samples before late-onset or term preeclampsia diagnosis. The search retrieved 4,257 records, of which 125 studies were included in the final assessment. The results demonstrate that no single molecular biomarker presents sufficient clinical sensitivity and specificity for screening late-onset and term preeclampsia. Multivariable models combining maternal risk factors with biochemical and/or biophysical markers generate higher detection rates, but they need more effective biomarkers and validation data for clinical utility. This review proposes that further research into novel biomarkers for late-onset and term preeclampsia is warranted and important to find strategies to predict this complication. Other critical factors to help identify candidate markers should be considered, such as a consensus on defining preeclampsia subtypes, optimal testing time, and sample types.

Soluble endoglin versus sFlt-1/PlGF ratio: detection of preeclampsia, HELLP syndrome, and FGR in a high-risk cohort

The angiogenic factors sFlt-1 and PlGF play an established role in the detection of preeclampsia (PE). Recent data suggest that sEng might contribute to the pathogenesis of PE. However, only a few studies so far have addressed its role.This monocentric cross-sectional study of high-risk pregnancies aims to compare the levels of sFlt-1/PlGF ratio and sEng depending on different placental-related adverse pregnancy outcomes. The statistical analysis takes into account Pearson's correlation coefficient between angiogenic factors, the area under the curve estimates (AUCs) for detection, and adjusted odds ratios (aOR) with 95% confidence intervals (95%-CIs). The analysis included 206 patients: 60 controls, 90 PE (59 EOPE, 35 LOPE), 94 FGR, and 35 HELLP cases. Some outcomes overlapped because FGR commonly complicated PE and HELLP syndrome. Serum levels of sFlt-1/PlGF and sEng correlated with each other. Higher levels were observed in HELLP syndrome and EOPE cases. AUCs for sFlt-1/PlGF ratio and sEng were, respectively, 0.915 (95%-Cl 0.87-0.96) and 0.872 (95%-Cl 0.81-0.93) in PE, 0.895 (95%-Cl 0.83-0.96) and 0.878 (95%-Cl 0.81-0.95) in HELLP syndrome, 0.891 (95%-Cl 0.84-0.94), and 0.856 (95%-Cl 0.79-0.92) in FGR.aORsfor sFlt-1/PlGF ratio and sEng were, respectively: 2.69 (95%-Cl 1.86-3.9) and 2.33 (95%-Cl 1.59-3.48) in PE, 2.38 (95%-Cl 1.64-3.44) and 2.28 (95%-Cl 1.55-3.4) in FGR, and 2.10 (95%-Cl 1.45-3.05) and 1.88 (95%-Cl 1.31-2.69) in HELLP syndrome. In addition, the aORs between sFlt-1/PlGF and sEng were very similar but higher for PE and FGR than HELLP syndrome.In conclusion,sEng performed similarly to sFlt-1/PlGF to detect placental dysfunctions.

The prediction of early preeclampsia: Results from a longitudinal proteomics study

OBJECTIVES

To identify maternal plasma protein markers for early preeclampsia (delivery <34 weeks of gestation) and to determine whether the prediction performance is affected by disease severity and presence of placental lesions consistent with maternal vascular malperfusion (MVM) among cases.

STUDY DESIGN

This longitudinal case-control study included 90 patients with a normal pregnancy and 33 patients with early preeclampsia. Two to six maternal plasma samples were collected throughout gestation from each woman. The abundance of 1,125 proteins was measured using high-affinity aptamer-based proteomic assays, and data were modeled using linear mixed-effects models. After data transformation into multiples of the mean values for gestational age, parsimonious linear discriminant analysis risk models were fit for each gestational-age interval (8-16, 16.1-22, 22.1-28, 28.1-32 weeks). Proteomic profiles of early preeclampsia cases were also compared to those of a combined set of controls and late preeclampsia cases (n = 76) reported previously. Prediction performance was estimated via bootstrap.

RESULTS

We found that 1) multi-protein models at 16.1-22 weeks of gestation predicted early preeclampsia with a sensitivity of 71% at a false-positive rate (FPR) of 10%. High abundance of matrix metalloproteinase-7 and glycoprotein IIbIIIa complex were the most reliable predictors at this gestational age; 2) at 22.1-28 weeks of gestation, lower abundance of placental growth factor (PlGF) and vascular endothelial growth factor A, isoform 121 (VEGF-121), as well as elevated sialic acid binding immunoglobulin-like lectin 6 (siglec-6) and activin-A, were the best predictors of the subsequent development of early preeclampsia (81% sensitivity, FPR = 10%); 3) at 28.1-32 weeks of gestation, the sensitivity of multi-protein models was 85% (FPR = 10%) with the best predictors being activated leukocyte cell adhesion molecule, siglec-6, and VEGF-121; 4) the increase in siglec-6, activin-A, and VEGF-121 at 22.1-28 weeks of gestation differentiated women who subsequently developed early preeclampsia from those who had a normal pregnancy or developed late preeclampsia (sensitivity 77%, FPR = 10%); 5) the sensitivity of risk models was higher for early preeclampsia with placental MVM lesions than for the entire early preeclampsia group (90% versus 71% at 16.1-22 weeks; 87% versus 81% at 22.1-28 weeks; and 90% versus 85% at 28.1-32 weeks, all FPR = 10%); and 6) the sensitivity of prediction models was higher for severe early preeclampsia than for the entire early preeclampsia group (84% versus 71% at 16.1-22 weeks).

CONCLUSION

We have presented herein a catalogue of proteome changes in maternal plasma proteome that precede the diagnosis of preeclampsia and can distinguish among early and late phenotypes. The sensitivity of maternal plasma protein models for early preeclampsia is higher in women with underlying vascular placental disease and in those with a severe phenotype.

Integrated Proteomic and Metabolomic prediction of Term Preeclampsia

Term preeclampsia (tPE), ≥37 weeks, is the most common form of PE and the most difficult to predict. Little is known about its pathogenesis. This study aims to elucidate the pathogenesis and assess early prediction of tPE using serial integrated metabolomic and proteomic systems biology approaches. Serial first- (11-14 weeks) and third-trimester (30-34 weeks) serum samples were analyzed using targeted metabolomic (¹H NMR and DI-LC-MS/MS) and proteomic (MALDI-TOF/TOF-MS) platforms. We analyzed 35 tPE cases and 63 controls. Serial first- (sphingomyelin C18:1 and urea) and third-trimester (hexose and citrate) metabolite screening predicted tPE with an area under the receiver operating characteristic curve (AUC) (95% CI) = 0.817 (0.732-0.902) and a sensitivity of 81.6% and specificity of 71.0%. Serial first [TATA box binding protein-associated factor (TBP)] and third-trimester [Testis-expressed sequence 15 protein (TEX15)] protein biomarkers highly accurately predicted tPE with an AUC (95% CI) of 0.987 (0.961-1.000), sensitivity 100% and specificity 98.4%. Integrated pathway over-representation analysis combining metabolomic and proteomic data revealed significant alterations in signal transduction, G protein coupled receptors, serotonin and glycosaminoglycan metabolisms among others. This is the first report of serial integrated and combined metabolomic and proteomic analysis of tPE. High predictive accuracy and potentially important pathogenic information were achieved.

Maternal circulating levels of transforming growth factor-β superfamily and its soluble receptors in hypertensive disorders of pregnancy

OBJECTIVE

To assess circulating levels of transforming growth factor (TGF)-β superfamily members and their soluble receptors in hypertensive disorders of pregnancy, and to investigate associations with clinical manifestations.

METHODS

A retrospective study was conducted using data for women admitted to a center in China for delivery between May 2011 and April 2013. Women with severe pre-eclampsia, mild pre-eclampsia, and gestational hypertension were included, along with a control group. Serum levels of activin A, inhibin A, TGF-β1, soluble endoglin (sEng), and soluble betaglycan (sBG) were measured.

RESULTS

Women with severe pre-eclampsia (n = 17) had higher mean levels of activin A (23.5±2.1 μg/L), inhibin A (1.7±0.2 μg/L), sEng (32.1±3.2 μg/L), and sBG (84.1±9.4 μg/L) than did normotensive controls (n = 18), women with gestational hypertension (n = 15), and those with mild pre-eclampsia (n = 14; all P<0.05). Women with early-onset pre-eclampsia (n = 13) had higher levels of these serum markers than did preterm normotensive controls (n = 8; all P<0.001). Women with severe or early-onset pre-eclampsia had the lowest TGF-β1 levels. Activin A, inhibin A, sEng, and sBG levels were positively correlated with mean arterial pressure and proteinuria (all P<0.01).

CONCLUSION

Pre-eclampsia is associated with an imbalance of members of the TGF-β superfamily and their soluble receptors, which might contribute to the development of pre-eclampsia and help to predict onset and severity.

Altered Biomarkers in Trophoblast Cells Obtained Noninvasively Prior to Clinical Manifestation of Perinatal Disease

A contributing factor to poor placental perfusion, leading to intrauterine growth restriction and preeclampsia, is the failure of invading extravillous trophoblast (EVT) cells to remodel the maternal uterine arteries during the first and second trimesters of pregnancy. Noninvasive assessment of EVT cells in ongoing pregnancies is possible beginning three weeks after conception, using trophoblast retrieval and isolation from the cervix (TRIC). Seven proteins were semi-quantified by immunofluorescence microscopy in EVT cells obtained between gestational weeks 6 and 20 from pregnancies with normal outcomes (N = 29) and those with intrauterine growth restriction or preeclampsia (N = 12). Significant differences were measured in expression of PAPPA, FLT1, ENG, AFP, PGF, and LGALS14, but not LGALS13 or the lineage marker KRT7. These findings provide for the first time direct evidence of pathology-associated protein dysregulation in EVT cells during early placentation. The TRIC platform provides a novel approach to acquire molecular signatures of EVT cells that can be correlated with pregnancy outcome.

Update on the pathophysiological implications and clinical role of angiogenic factors in pregnancy

Angiogenic markers are now being incorporated into clinical practice for the screening, diagnosing, and monitoring of preeclampsia. Pregnancy requires both vasculogenesis and angiogenesis in the fetal compartment and angiogenesis in the maternal compartment. Abnormal angiogenesis in the placenta determines impaired remodeling of the maternal spiral arteries and placental underperfusion that may ultimately lead to fetal growth restriction and maternal preeclampsia. The dysregulation of angiogenesis in the placenta and maternal-fetal circulation has emerged as one of the main pathophysiological features in the development of placental insufficiency and its clinical consequences. Abnormal angiogenesis has also been related to other obstetric and fetal conditions such as peripartum cardiomyopathy and fetal cardiac defects. This opens up new challenges for our understanding of angiogenic involvement in maternal cardiovascular function and fetal cardiac development, and it offers new clinical opportunities. This review summarizes the current knowledge of the pathophysiological implications and the clinical role of angiogenic factors in pregnancy.

Brachial Artery Flow Mediated Dilation in the First Trimester to Predict the Occurrence of Hypertensive Disorders during Pregnancy

Objectives: To determine whether brachial artery flow-mediated dilation (FMD) assessed by ultrasonography during the late first trimester is able to predict the occurrence of hypertensive disorders during pregnancy. Methods: Maternal endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery in 487 pregnant women at 11-13+6 weeks' gestation. Subjects were prospectively followed and grouped according to the outcomes related to hypertensive disorders. We determined the areas under receiver operating characteristic (ROC) curve with their respective 95% confidence intervals (CI) for using low FMD results to predict the occurrence of hypertensive disorders during pregnancy. Results: Among 487 women, 9 (1.8%) were diagnosed with early-onset preeclampsia, 22 (4.5%) were diagnosed with late-onset preeclampsia, 47 (9.7%) developed gestational hypertension, and the remaining 409 (84%) pregnancies were unaffected by hypertensive disorders. Area under ROC curve analyses demonstrated that FMD was not able to predict pregnancies that developed hypertensive disorders. Conclusions: We conclude that FMD should not be considered a potential first-trimester marker of hypertensive disorders during pregnancy.

Longitudinal changes in maternal soluble endoglin and angiopoietin-2 in women at risk for pre-eclampsia

OBJECTIVE

To investigate longitudinal changes in maternal plasma levels of soluble endoglin (sEng) and angiopoietin-2 (Ang-2) in pregnant women who develop pre-eclampsia (PE) and gestational hypertension (GH).

METHODS

This was a nested case-control study drawn from a larger prospective longitudinal study in singleton pregnancies identified by screening at 11 + 0 to 13 + 6 weeks' gestation as being at high-risk for PE. Blood samples were taken every 4 weeks until delivery. Values were compared in women who developed preterm PE (requiring delivery before 37 weeks), term PE, GH and those who remained normotensive.

RESULTS

A total of 471 samples were analyzed in 122 women, comprising 85 who remained normotensive, 12 who developed GH, 13 who developed term PE and 12 who developed preterm PE. In the normotensive group, there was an increase in log10 sEng levels with gestational age. In the preterm PE group, compared with the normotensive group, sEng was higher from 18 weeks onwards, and the difference increased significantly with gestational age (P < 0.001). In the GH and term PE groups, sEng did not differ significantly from that of the normotensive group (P = 0.583 and P = 0.890, respectively). The square root of Ang-2 decreased significantly with gestational age, but did not differ significantly among the different outcome groups (P = 0.571).

CONCLUSION

Maternal plasma sEng, but not Ang-2, may be a useful mid- and late-gestation biomarker for the development of PE.

Pre-eclampsia part 2: prediction, prevention and management

An antiangiogenic state might constitute a terminal pathway for the multiple aetiologies of pre-eclampsia, especially those resulting from placental abnormalities. The levels of angiogenic and antiangiogenic proteins in maternal blood change prior to a diagnosis of pre-eclampsia, correlate with disease severity and have prognostic value in identifying women who will develop maternal and/or perinatal complications. Potential interventions exist to ameliorate the imbalance of angiogenesis and, hence, might provide opportunities to improve maternal and/or perinatal outcomes in pre-eclampsia. Current strategies for managing pre-eclampsia consist of controlling hypertension, preventing seizures and timely delivery of the fetus. Prediction of pre-eclampsia in the first trimester is of great interest, as early administration of aspirin might reduce the risk of pre-eclampsia, albeit modestly. Combinations of biomarkers typically predict pre-eclampsia better than single biomarkers; however, the encouraging initial results of biomarker studies require external validation in other populations before they can be used to facilitate intervention in patients identified as at increased risk. Angiogenic and antiangiogenic factors might also be useful in triage of symptomatic patients with suspected pre-eclampsia, differentiating pre-eclampsia from exacerbations of pre-existing medical conditions and performing risk assessment in asymptomatic women. This Review article discusses the performance of predictive and prognostic biomarkers for pre-eclampsia, current strategies for preventing and managing the condition and its long-term consequences.