Reduction of the disintegrin and metalloprotease ADAM12 in preeclampsia

The significance of mitochondrial haplogroups in preeclampsia risk

OBJECTIVE

To determine whether mitochondrial haplogroups function as disease-modifiers or as susceptibility factors in preeclampsia using a traditional haplogroup association model.

METHODS

This retrospective study haplotyped 235 control and 78 preeclamptic pregnancies from Denmark using either real-time PCR or Sanger sequencing depending on the rarity of the haplogroup.

RESULTS

No significant association between haplogroups and the risk of preeclampsia was found, nor was any role for haplogroups in disease severity uncovered.

CONCLUSION

Mitochondrial haplogroups are not associated with preeclampsia or the severity of preeclampsia in the Danish population. However, this study cannot exclude a role for less common mtDNA variation. Models that can examine these should be applied in preeclamptic patients.

Proteomic profile of extracellular vesicles in maternal plasma of women with fetal death

OBJECTIVES

Fetal death is a complication of pregnancy caused by multiple etiologies rather than being the end-result of a single disease process. Many soluble analytes in the maternal circulation, such as hormones and cytokines, have been implicated in its pathophysiology. However, changes in the protein content of extracellular vesicles (EVs), which could provide additional insight into the disease pathways of this obstetrical syndrome, have not been examined. This study aimed to characterize the proteomic profile of EVs in the plasma of pregnant women who experienced fetal death and to evaluate whether such a profile reflected the pathophysiological mechanisms of this obstetrical complication. Moreover, the proteomic results were compared to and integrated with those obtained from the soluble fraction of maternal plasma.

METHODS

This retrospective case-control study included 47 women who experienced fetal death and 94 matched, healthy, pregnant controls. Proteomic analysis of 82 proteins in the EVs and the soluble fractions of maternal plasma samples was conducted by using a bead-based, multiplexed immunoassay platform. Quantile regression analysis and random forest models were implemented to assess differences in the concentration of proteins in the EV and soluble fractions and to evaluate their combined discriminatory power between clinical groups. Hierarchical cluster analysis was applied to identify subgroups of fetal death cases with similar proteomic profiles. A p-value of <.05 was used to infer significance, unless multiple testing was involved, with the false discovery rate controlled at the 10% level (q < 0.1). All statistical analyses were performed by using the R statistical language and environment-and specialized packages.

RESULTS

Nineteen proteins (placental growth factor, macrophage migration inhibitory factor, endoglin, regulated upon activation normal T cell expressed and presumably secreted (RANTES), interleukin (IL)-6, macrophage inflammatory protein 1-alpha, urokinase plasminogen activator surface receptor, tissue factor pathway inhibitor, IL-8, E-Selectin, vascular endothelial growth factor receptor 2, pentraxin 3, IL-16, galectin-1, monocyte chemotactic protein 1, disintegrin and metalloproteinase domain-containing protein 12, insulin-like growth factor-binding protein 1, matrix metalloproteinase-1(MMP1), and CD163) were found to have different plasma concentrations (of an EV or a soluble fraction) in women with fetal death compared to controls. There was a similar pattern of change for the dysregulated proteins in the EV and soluble fractions and a positive correlation between the log₂-fold changes of proteins significant in either the EV or the soluble fraction (ρ = 0.89, p < .001). The combination of EV and soluble fraction proteins resulted in a good discriminatory model (area under the ROC curve, 82%; sensitivity, 57.5% at a 10% false-positive rate). Unsupervised clustering based on the proteins differentially expressed in either the EV or the soluble fraction of patients with fetal death relative to controls revealed three major clusters of patients.

CONCLUSION

Pregnant women with fetal death have different concentrations of 19 proteins in the EV and soluble fractions compared to controls, and the direction of changes in concentration was similar between fractions. The combination of EV and soluble protein concentrations revealed three different clusters of fetal death cases with distinct clinical and placental histopathological characteristics.

From Biomarkers to the Molecular Mechanism of Preeclampsia-A Comprehensive Literature Review

Preeclampsia (PE) is a prevalent obstetric illness affecting pregnant women worldwide. This comprehensive literature review aims to examine the role of biomarkers and understand the molecular mechanisms underlying PE. The review encompasses studies on biomarkers for predicting, diagnosing, and monitoring PE, focusing on their molecular mechanisms in maternal blood or urine samples. Past research has advanced our understanding of PE pathogenesis, but the etiology remains unclear. Biomarkers such as PlGF, sFlt-1, PP-13, and PAPP-A have shown promise in risk classification and preventive measures, although challenges exist, including low detection rates and discrepancies in predicting different PE subtypes. Future perspectives highlight the importance of larger prospective studies to explore predictive biomarkers and their molecular mechanisms, improving screening efficacy and distinguishing between early-onset and late-onset PE. Biomarker assessments offer reliable and cost-effective screening methods for early detection, prognosis, and monitoring of PE. Early identification of high-risk women enables timely intervention, preventing adverse outcomes. Further research is needed to validate and optimize biomarker models for accurate prediction and diagnosis, ultimately improving maternal and fetal health outcomes.

First-Trimester Maternal Serum Adiponectin/Leptin Ratio in Pre-Eclampsia and Fetal Growth

The serum adiponectin/leptin ratio (A/L ratio) is a surrogate marker of insulin sensitivity. Pre-eclampsia (PE) is associated with maternal metabolic syndrome and occasionally impaired fetal growth. We assessed whether the A/L ratio in first-trimester maternal serum was associated with PE and/or birth weight. Adiponectin and leptin were quantitated in first-trimester blood samples (gestational week 10+3−13+6) from 126 women who later developed PE with proteinuria (98 mild PE; 21 severe PE; 7 HELLP syndrome), and 297 controls, recruited from the Copenhagen First-Trimester Screening Study. The A/L ratio was reduced in PE pregnancies, median 0.17 (IQR: 0.12−0.27) compared with controls, median 0.32 (IQR: 0.19−0.62) (p < 0.001). A multiple logistic regression showed that PE was negatively associated with log A/L ratio independent of maternal BMI (odds ratio = 0.315, 95% CI = 0.191 to 0.519). Adiponectin (AUC = 0.632) and PAPP-A (AUC = 0.605) were negatively associated with PE, and leptin (AUC = 0.712) was positively associated with PE. However, the A/L ratio was a better predictor of PE (AUC = 0.737), albeit not clinically relevant as a single marker. No significant association was found between A/L ratio and clinical severity of pre-eclampsia or preterm birth. PE was associated with a significantly lower relative birth weight (p < 0.001). A significant negative correlation was found between relative birth weight and A/L ratio in controls (β = −0.165, p < 0.05) but not in PE pregnancies), independent of maternal BMI. After correction for maternal BMI, leptin was significantly associated with relative birth weight (β = 2.98, p < 0.05), while adiponectin was not significantly associated. Our findings suggest that an impairment of the A/L ratio (as seen in metabolic syndrome) in the first trimester is characteristic of PE, while aberrant fetal growth in PE is not dependent on insulin sensitivity, but rather on leptin-associated pathways.

Role of ADAM and ADAMTS Disintegrin and Metalloproteinases in Normal Pregnancy and Preeclampsia

Normal pregnancy (NP) involves intricate processes starting with egg fertilization, proceeding to embryo implantation, placentation and gestation, and culminating in parturition. These pregnancy-related processes require marked uteroplacental and vascular remodeling by proteolytic enzymes and metalloproteinases. A disintegrin and metalloproteinase (ADAM) and ADAM with thrombospondin motifs (ADAMTS) are members of the zinc-dependent family of proteinases with highly conserved protein structure and sequence homology, which include a pro-domain, and a metalloproteinase, disintegrin and cysteine-rich domain. In NP, ADAMs and ADAMTS regulate sperm-egg fusion, embryo implantation, trophoblast invasion, placental angiogenesis and spiral arteries remodeling through their ectodomain proteolysis of cell surface cytokines, cadherins and growth factors as well as their adhesion with integrins and cell-cell junction proteins. Preeclampsia (PE) is a serious complication of pregnancy characterized by new-onset hypertension (HTN) in pregnancy (HTN-Preg) at or after 20 weeks of gestation, with or without proteinuria. Insufficient trophoblast invasion of the uterine wall, inadequate expansive remodeling of the spiral arteries, reduced uteroplacental perfusion pressure, and placental ischemia/hypoxia are major initiating events in the pathogenesis of PE. Placental ischemia/hypoxia increase the release of reactive oxygen species (ROS), which lead to aberrant expression/activity of certain ADAMs and ADAMTS. In PE, abnormal expression/activity of specific ADAMs and ADAMTS that function as proteolytic sheddases could alter proangiogenic and growth factors, and promote the release of antiangiogenic factors and inflammatory cytokines into the placenta and maternal circulation leading to generalized inflammation, endothelial cell injury and HTN-Preg, renal injury and proteinuria, and further decreases in uteroplacental blood flow, exaggeration of placental ischemia, and consequently fetal growth restriction. Identifying the role of ADAMs and ADAMTS in NP and PE has led to a better understanding of the underlying molecular and vascular pathways, and advanced the potential for novel biomarkers for prediction and early detection, and new approaches for the management of PE.

Longitudinal Proteomic Analysis of Plasma across Healthy Pregnancies Reveals Indicators of Gestational Age

Longitudinal changes in the blood proteome during gestation relate to fetal development and maternal homeostasis. Charting the maternal blood proteome in normal pregnancies is critical for establishing a baseline reference when assessing complications and disease. Using mass spectrometry-based shotgun proteomics, we surveyed the maternal plasma proteome across uncomplicated pregnancies. Results indicate a significant rise in proteins that govern placentation and are vital to the development and health of the fetus. Importantly, we uncovered proteome signatures that strongly correlated with gestational age. Fold increases and correlations between the plasma concentrations of ADAM12 (ρ = 0.973), PSG1 (ρ = 0.936), and/or CSH1/2 (ρ = 0.928) with gestational age were validated with ELISA. Proteomic and validation analyses demonstrate that the maternal plasma concentration of ADAM12, either independently or in combination with either PSG1 or CSH1/2, correlates with gestational age within ±8 days throughout pregnancy. These findings suggest that the gestational age in healthy pregnancies may be determined by referencing the concentration of select plasma proteins.

A disintegrin and metalloproteinase 12 (ADAM12) is reduced at 36 weeks' gestation in pregnancies destined to deliver small for gestational age infants

First trimester circulating ADAM12 is reduced in fetal growth restriction (FGR) and preeclampsia. We measured plasma ADAM12 at 36 weeks' gestation preceding diagnosis of term preeclampsia or delivery of a small for gestational age (SGA; birthweight <10th centile) infant in two independent cohorts (Cohort 1 90 SGA, 41 preeclampsia, 862 controls; Cohort 2121 SGA 23 preeclampsia; 190 controls). ADAM12 was reduced with SGA in both cohorts (p = 0.0015 and 0.011 respectively), and further reduced with birthweight <5th centile (p = 0.0013 and 0.0058 respectively). This validates ADAM12 as an SGA biomarker near term. Circulating ADAM12 preceding preeclampsia was not consistently altered.

Preeclampsia and the challenge of early prediction: reality or utopia? State of art and critical review of literature

Purpose: The challenge to obtain improved predictive tools, able to identify women destined to develop preeclampsia (PE), is raising the interest of researchers for the attractive chance to allow for timely initiation of prophylactic therapy, appropriate antenatal surveillance, and better-targeted research into preventive interventions. We aimed to gather all the evidence reported up to now in scientific literature relating to all prediction tests for PE.Materials and methods: We searched articles on conventional literature platforms from January 1952 to August 2016, using the terms "preeclampsia," "gestational preeclampsia," and "gestational hypertensive disorders" combined with "predictive test" and "risk assessment." Abstracts/titles identified by the search were screened by three investigators.Results: The search identified 203 citations, of which 154 potentially relevant after the initial evaluation. Among these studies, 20 full articles were excluded, therefore, 134 primary studies met the criteria for inclusion and were analyzed.Conclusions: Current evidence suggests that a combination of several features may provide the best predictive accuracy for the identification of PE. Large-scale, multicenter, multiethnic, prospective trials are required to propose an ideal combination of markers for routine screening.

Clinical Presentation of Preeclampsia and the Diagnostic Value of Proteins and Their Methylation Products as Biomarkers in Pregnant Women with Preeclampsia and Their Newborns

Preeclampsia (PE) is a disorder which affects 1-10% of pregnant women worldwide. It is characterised by hypertension and proteinuria in the later stages of gestation and can lead to maternal and perinatal morbidity and mortality. Other than the delivery of the foetus and the removal of the placenta, to date there are no therapeutic approaches to treat or prevent PE. It is thus only possible to reduce PE-related mortality through early detection, careful monitoring, and treatment of the symptoms. For these reasons the search for noninvasive, blood-borne, or urinary biochemical markers that could be used for the screening, presymptomatic diagnosis, and prediction of the development of PE is of great urgency. So far, a number of biomarkers have been proposed for predicting PE, based on pathophysiological observations, but these have mostly proven to be unreliable and inconsistent between different studies. The clinical presentation of PE and data gathered for the biochemical markers placental growth factor (PlGF), soluble Feline McDonough Sarcoma- (fms-) like tyrosine kinase-1 (sFlt-1), asymmetric dimethylarginine (ADMA), and methyl-lysine is being reviewed with the aim of providing both a clinical and biochemical understanding of how these biomarkers might assist in the diagnosis of PE or indicate its severity.

Preeclampsia biomarkers: An assessment of maternal cardiometabolic health

Preeclampsia is a serious pregnancy condition defined as new-onset hypertension and proteinuria, commonly characterized as either early, 'placental', or late onset, 'maternal', using a cut-off of 34 weeks gestation. However, it may be more useful to differentiate between the vascular remodelling and placental invasion vs. inflammation and metabolic pathophysiology that underlie these forms of preeclampsia. Due to rising rates of obesity, the late-onset, maternal form is increasingly occurring earlier in pregnancy. Predictive tests for preeclampsia typically include biophysical markers such as maternal body mass index and mean arterial pressure, indicating the importance of cardiovascular and metabolic health in its pathophysiology. In contrast, the placental, inflammatory, endothelial and/or metabolic biomarkers used in these tests are generally thought to indicate an abnormal response to placentation and predict the disease. However, many of these non-placental biomarkers are known to predict impaired metabolic health in non-pregnant subjects with obesity (metabolically unhealthy obesity) and coronary artery disease or stroke in people at risk for cardiovascular events. Similarities between the performance of these markers in the prediction of cardiovascular and metabolic health outside of pregnancy suggests that they may be more indicative of maternal health than predictive for preeclampsia. This paper reviews the biophysical and biochemical markers in preeclampsia prediction and compares their performance to tests assessing metabolic health and risk of cardiovascular disease, particularly in the obese population.

First trimester maternal serum analytes and second trimester uterine artery Doppler in the prediction of preeclampsia and fetal growth restriction

OBJECTIVE

This study aimed to determine whether pregnancy-associated plasma protein-A (PAPP-A), free β-human chorionic gonadotropin (β-hCG), a disintegrin and metalloprotease 12 (ADAM12), and placenta protein 13 (PP13) in the first trimester, and uterine artery Doppler (UAD) in the second trimester, predict preeclampsia and fetal growth restriction (FGR).

MATERIALS AND METHODS

Maternal serum levels of PAPP-A, free β-hCG, ADAM12, and PP13 at 11-13⁺⁶ weeks of gestation and bilateral uterine artery pulsatility index (PI) at 22-24 weeks of gestation were measured in a nested case-control study within a prospective cohort. The serum analytes and Doppler measurements were compared for uncomplicated pregnancies and pregnancies complicated by preeclampsia and FGR. The efficacy of biochemical and Doppler measurements for the prediction of preelampsia and FGR was investigated.

RESULTS

Compared with gestational age-matched controls (n = 200), the mean PAPP-A and ADAM12 were lower (P < 0.001, P < 0.05) in pregnancies complicated by preeclampsia (n = 462) and FGR (n = 350). The median uterine artery mean PI was higher (P < 0.001) in preeclampsia and FGR groups. However, the median free β-hCG and PP13 were not significantly different from normal (P > 0.05). In screening for preeclampsia and FGR, assuming a fixed false positive rate (FPR) of 10%, the detection rates were 72% and 68% for a combination of PAPP-A, ADAM12, and UAD, respectively.

CONCLUSION

First trimester PAPP-A and ADAM12 levels and second trimester uterine artery PI are associated with adverse pregnancy outcomes. The combination of biochemical markers and UAD improves the screening efficiency for the prediction of preeclampsia and FGR.

Prediction and prevention of pre-eclampsia in Asian subpopulation

The benefit of the early administration of aspirin to reduce preterm pre-eclampsia among screened positive European women from multivariate algorithmic approach (ASPRE trial) has opened an intense debate on the feasibility of universal screening. This review aims to assess the new perspectives in the combined screening of pre-eclampsia in the first trimester of pregnancy and the chances for prevention using low-dose aspirin with special emphasis on the particularities of the Asian population. PubMed, CENTRAL and Embase databases were searched from inception until 15 November 2017 using combinations of the search terms: preeclampsia, Asian, prenatal screening, early prediction, ultrasonography, pregnancy, biomarker, mean arterial pressure, soluble fms-like tyrosine kinase-1, placental growth factor, pregnancy-associated plasma protein-A and pulsatility index. This is not a systematic review or meta-analysis, so the risk of bias of the selected published articles and heterogeneity among the studies need to be considered. The prevalence of pre-eclampsia and serum levels of biochemical markers in Asian are different from Caucasian women; hence, Asian ethnicity needs to be corrected for in the algorithmic assessment of multiple variables to improve the screening performance. Aspirin prophylaxis may still be viable in Asian women, but resource implication needs to be considered. Asian ethnicity should be taken into account before implementing pre-eclampsia screening strategies in the region. The variables included can be mixed and matched to achieve an optimal performance that is appropriate for economical restriction in individual countries.

Placental protein-13 (PP13) in combination with PAPP-A and free leptin index (fLI) in first trimester maternal serum screening for severe and early preeclampsia

Background:

Placental protein-13 (PP13) is involved in placental invasion and has been suggested as a maternal serum marker of preeclampsia (PE) development. However, the discriminatory ability of PP13 in first trimester has not been completely clarified.

Methods:

PP13 was measured in first trimester (week 10+3–13+6) maternal serum from 120 PE pregnancies and 267 control pregnancies and was correlated with clinical parameters. The population screening performance of PP13 in combination with the PE markers pregnancy associated plasma protein A (PAPPA) and free leptin index (fLI) was assessed by Monte Carlo simulation.

Results:

In severe PE (including HELLP) cases (n=26) the median PP13 concentration was 35.8 pg/mL (range: 17.8–85.5 pg/mL) and in PE pregnancies (n=10) with birth prior to week 34, the median PP13 concentration was 30.6 pg/mL (13.1–50.1 pg/mL), compared to controls with a median of 54.8 pg/mL (range: 15.4–142.6 pg/mL) (p<0.04). The population screening detection rate (DR) for a false-positive rate of 10% for severe PE and HELLP was 26% for PP13, 28% for PP13+PAPP-A, 33% for PP13+fLI, and 40% for PP13+PAPP-A+fLI.

Conclusions:

PP13 is a marker of severe PE and HELLP syndrome. The screening performance of PP13 can be markedly improved by combining it with fLI and PAPP-A.

The role of ADAMTS genes in preeclampsia

Preeclampsia is a complex disease that increases both maternal and fetal morbidity and mortality in both developed and developing countries. It complicates around 5-10% of all pregnancies..The pathophysiology of preeclampsia includes both maternal and fetal/placental factors. Implantation of embryo and placentation are crucial steps for development of pregnancy involving trophoblast invasion. Abnormalities of spiral artery invasion, trophoblast function, inflammatory process, and biologic functions of angiogenic/anti-angiogenic factors early in pregnancy result in pregnancy diseases, including preeclampsia. ADAMTS genes are members of the family of matrix metalloproteinase, which have important tasks in extracellular matrix (ECM) degradation and repair processes. The roles of ADAMTS in preeclampsia may include regulation of spiral artery invasion and ECM arrangement of the placenta.

Evaluation of ADAMTS12, ADAMTS16, ADAMTS18 and IL-33 serum levels in pre-eclampsia

OBJECTIVE

Pre-eclampsia is the result of impaired trophoblast invasion and spiral artery remodeling managed by inflammatory response in its etiology and physiopathology. The aim of this study was to compare serum molecules including IL-33, ADAMTS12, ADAMTS16 and ADAMTS18 levels between pre-eclampsia and control groups and to investigate the role of these molecules in pre-eclampsia.

METHODS

Forty-one women diagnosed as pre-eclampsia between 30 and 40 weeks of gestation and 41 non-complicated pregnant women were enrolled in this cross-sectional, case-control prospective study. ELISA method was used to determine IL-33, ADAMTS12, ADAMTS16 and ADAMTS18 levels within serums in two groups.

RESULTS

Serum ADAMTS12 and IL-33 levels were significantly lower in pre-eclampsia group (p < 0.001 and p: 0.028, respectively), however, in sub-group analysis, no significant difference was observed (p > 0.05). The cut-off value of ADAMTS12 levels to discriminate pre-eclampsia with %73.17 sensitivity and %92.68 specificity was 8.27 ng/ml while the cut-off value for IL-33 was 0.23 pg/ml with 82.93% sensitivity and 53.66% specificity.

CONCLUSION

Pre-eclampsia is associated with lower serum IL-33 and ADAMTS12 levels.

Combined Screening for Early Detection of Pre-Eclampsia

Although the precise pathophysiology of pre-eclampsia remains unknown, this condition continues to be a major cause of maternal and fetal mortality. Early prediction of pre-eclampsia would allow for timely initiation of preventive therapy. A combination of biophysical and biochemical markers are superior to other tests for early prediction of the development of pre-eclampsia. Apart from the use of parameters in first-trimester aneuploidy screening, cell-free fetal DNA quantification is emerging as a promising marker for prediction of pre-eclampsia. This article reviews the current research of the most important strategies for prediction of pre-eclampsia, including the use of maternal risk factors, mean maternal arterial pressure, ultrasound parameters, and biomarkers.

Mass spectrometry-based proteomics for pre-eclampsia and preterm birth

Pregnancy-related complications such as pre-eclampsia and preterm birth now represent a notable burden of adverse health. Pre-eclampsia is a hypertensive disorder unique to pregnancy. It is an important cause of maternal death worldwide and a leading cause of fetal growth restriction and iatrogenic prematurity. Fifteen million infants are born preterm each year globally, but more than one million of those do not survive their first month of life. Currently there are no predictive tests available for diagnosis of these pregnancy-related complications and the biological mechanisms of the diseases have not been fully elucidated. Mass spectrometry-based proteomics have all the necessary attributes to provide the needed breakthrough in understanding the pathophysiology of complex human diseases thorough the discovery of biomarkers. The mass spectrometry methodologies employed in the studies for pregnancy-related complications are evaluated in this article. Top-down proteomic and peptidomic profiling by laser mass spectrometry, liquid chromatography or capillary electrophoresis coupled to mass spectrometry, and bottom-up quantitative proteomics and targeted proteomics by liquid chromatography mass spectrometry have been applied to elucidate protein biomarkers and biological mechanism of pregnancy-related complications. The proteomes of serum, urine, amniotic fluid, cervical-vaginal fluid, placental tissue, and cytotrophoblastic cells have all been investigated. Numerous biomarkers or biomarker candidates that could distinguish complicated pregnancies from healthy controls have been proposed. Nevertheless, questions as to the clinically utility and the capacity to elucidate the pathogenesis of the pre-eclampsia and preterm birth remain to be answered.

The Elsevier Trophoblast Research Award Lecture: Importance of metzincin proteases in trophoblast biology and placental development: a focus on ADAM12

Placental development is a highly regulated process requiring signals from both fetal and maternal uterine compartments. Within this complex system, trophoblasts, placental cells of epithelial lineage, form the maternal-fetal interface controlling nutrient, gas and waste exchange. The commitment of progenitor villous cytotrophoblasts to differentiate into diverse trophoblast subsets is a fundamental process in placental development. Differentiation of trophoblasts into invasive stromal- and vascular-remodeling subtypes is essential for uterine arterial remodeling and placental function. Inadequate placentation, characterized by defects in trophoblast differentiation, may underlie the earliest cellular events driving pregnancy disorders such as preeclampsia and fetal growth restriction. Molecularly, invasive trophoblasts acquire characteristics defined by profound alterations in cell-cell and cell-matrix adhesion, cytoskeletal reorganization and production of proteolytic factors. To date, most studies have investigated the importance of the matrix metalloproteinases (MMPs) and their ability to efficiently remodel components of the extracellular matrix (ECM). However, it is now becoming clear that besides MMPs, other related proteases regulate trophoblast invasion via mechanisms other than ECM turnover. In this review, we will summarize the current knowledge on the regulation of trophoblast invasion by members of the metzincin family of metalloproteinases. Specifically, we will discuss the emerging roles that A Disintegrin and Metalloproteinases (ADAMs) play in placental development, with a particular focus on the ADAM subtype, ADAM12.

Development and validation of a risk factor scoring system for first-trimester prediction of preeclampsia

OBJECTIVE

The aim of this study was to develop a multiparameter risk-based scoring system for first-trimester prediction of preeclampsia and to validate this scoring system in our patient population.

STUDY DESIGN

Secondary analysis of a prospective cohort of 1,200 patients presenting for first-trimester aneuploidy screening. Maternal serum pregnancy-associated plasma protein A (PAPP-A) levels were measured and bilateral uterine artery (UA) Doppler studies performed. Using the first half of the study population, a prediction model for preeclampsia was created. Test performance characteristics were used to determine the optimal score for predicting preeclampsia. This model was then validated in the second half of the population.

RESULTS

Significant risk factors and their weighted scores derived from the prediction model were chronic hypertension (4), history of preeclampsia (3), pregestational diabetes (2), body mass index ≥ 30 kg/m(2) (2), bilateral UA notching (1), and PAPP-A MoM < 10 th percentile (1). The area under the curve (AUC) for the risk scoring system was 0.76 (95% confidence interval [CI], 0.69-0.83), and the optimal threshold for predicting preeclampsia was a total score of ≥ 6. This AUC did not differ significantly from the AUC observed in our validation cohort (AUC, 0.78 [95% CI, 0.69-0.86]; p = 0.75].

CONCLUSION

Our proposed risk factor scoring system demonstrates modest accuracy but excellent reproducibility for first-trimester prediction of preeclampsia.

Mid-trimester maternal ADAM12 levels differ according to fetal gender in pregnancies complicated by preeclampsia

An overrepresentation of adverse pregnancy outcomes has been observed in pregnancies associated with a male fetus. We investigated the association between fetal gender and candidate biomarkers for preeclampsia. Proteins were quantified in samples taken at 20 weeks from women recruited to the SCreening fOr Pregnancy Endpoints (SCOPE) study (preeclampsia n = 150; no preeclampsia n = 450). In contrast to placental growth factor, soluble endoglin, and insulin-like growth factor acid labile subunit, levels of metallopeptidase domain 12 (ADAM12) at 20 weeks were dependent on fetal gender in pregnancies complicated by preeclampsia, for male (n = 73) fetuses the multiples of the median (MoM; interquartile range [IQR] 1.1-1.5) was 1.3, whereas for female fetuses (n = 75) MoM was 1.1 (1.0-1.3); P < .01. Prediction of preeclampsia using ADAM12 levels was improved for pregnancies associated with a male fetus (area under receiver-operator curve [AUC] 0.73 [95% confidence interval [CI] 0.67-0.80]) than that of a female fetus (AUC 0.62 [0.55-0.70]); P = .03. The data presented here fit a contemporary hypothesis that there is a difference between the genders in response to an adverse maternal environment and suggest that an alteration in ADAM12 may reflect an altered placental response in pregnancies subsequently complicated by preeclampsia.

Pregnancy-associated plasma protein A (PAPP-A) and preeclampsia

Pregnancy-associated plasma protein A (PAPP-A) is a key regulator of insulin-like growth factor bioavailability essential for normal fetal development. In maternal blood, this protein increases with gestational age and then rapidly decreases after delivery. It is routinely used for Down syndrome screening in the first trimester of pregnancy, and its decrease compared to a normal pregnancy indicates an increased risk for both chromosomal anomalies and adverse pregnancy outcomes. It belongs to a group of biomarkers that predict later preeclampsia development, primarily early onset preeclampsia; however, it should be combined with a Doppler ultrasonography of the uterine artery (pulsatile index) and other biochemical and maternal factors to achieve a higher detection rate with an acceptable false positivity rate. Some studies have demonstrated an even more pronounced decrease of PAPP-A in the early second trimester of pregnancy in women who subsequently develop preeclampsia compared with women who do not develop preeclampsia. Conversely, during the last trimester of pregnancy, its concentration increases even more in patients with preeclampsia than in patients without. It is also detectable at very low levels in nonpregnant individuals, and a higher concentration indicates an adverse effect in patients with acute coronary syndromes or stable atherosclerotic disease and in patients with end-stage renal disease who are being treated with hemodialysis.

Maternal serum disintegrin and metalloprotease protein-12 in early pregnancy as a potential marker of adverse pregnancy outcomes

Objectives

The aim of this study was to determine whether the concentration of disintegrin and metalloprotease protein12 (ADAM12) in first trimester maternal serum can be used as a marker for first-trimester complete spontaneous abortions, missed abortions, ectopic pregnancies and hydatidiform moles.

Methods

The maternal serum concentrations of ADAM12 were measured in the range of 5–9⁺⁶ weeks of gestation using an automated AutoDelfia immunoassay platform in 9 cases of complete spontaneous abortion, 27 cases of missed abortions, 56 cases of ectopic pregnancies, 12 cases of hydatidiform moles, and 100 controls. Logistic regression analysis was used to determine significant factors for predicting adverse pregnancy outcomes in early pregnancy. Screening performance was assessed using receiver operating characteristic curves.

Results

Two hundred and four women were enrolled in the study. In the control group, the level of ADAM12 increased with gestational age. The median ADAM12 levels in the spontaneous abortion (0.430 MoM), ectopic pregnancy (0.460 MoM) and hydatidiform mole (0.037 MoM) groups were lower than that in the control group, while the median ADAM12 level in the missed abortion group (1.062 MoM) was not significant from the controls (1.002 MoM). Logistic regression analysis demonstrated that the level of ADAM12 in maternal serum facilitated the detection of ectopic pregnancies (OR = 0.909; 95% CI = 0.841∼0.982) and complete spontaneous abortion (OR = 0.863; 95% CI = 0.787∼0.946).

Conclusions

In complete spontaneous abortion and ectopic pregnancy, ADAM12 maintained at low levels in early pregnancies, and there were significant differences compared to normal pregnancies. ADAM12 is a promising marker for the diagnosis of complete spontaneous abortion and ectopic pregnancy in symptomatic women, and under certain conditions, ADAM12 can diagnose ectopic pregnancy and spontaneous abortion before an ultrasonographic detection of the conditions.

ADAM12s and PP13 as first trimester screening markers for adverse pregnancy outcome

BACKGROUND

The aim of the study was to assess the screening performance of first trimester maternal serum measurements of A-disintegrin-and-metalloprotease 12-s (ADAM12s) and placental protein 13 (PP13) for preeclampsia (PE), gestational hypertension (GH) and small-for-gestational-age (SGA) fetuses.

METHODS

In this retrospective case-control study 220 pregnant women were matched for gestational and maternal age at sampling. Results were expressed as multiples of the median (MoM) and compared using Kruskal-Wallis and Mann-Whitney U-test. Screening performance was assessed by receiver operator characteristics (ROC) curves and area under the curve (AUC).

RESULTS

Seventeen cases of PE, 30 cases of GH and eight cases of SGA fetuses were matched with 165 controls. ROC-analysis yielded AUCs for ADAM12s and PP13 of 0.63 and 0.59 for PE, 0.68 and 0.57 for GH and 0.59 and 0.62 for SGA, respectively. Combined ADAM12 and PP13 did not improve the AUC value. When the specificity was set at 80%, corresponding detection rate of ADAM12s was 52% for GH.

CONCLUSIONS

Combined ADAM12s and PP13 measurements do not predict adverse pregnancy outcome, but decreased first trimester ADAM12s levels are associated with GH.

Extravillous trophoblast-associated ADAM12 exerts pro-invasive properties, including induction of integrin beta 1-mediated cellular spreading

ADAM12, consisting of a membrane-bound (ADAM12L) and a secreted (ADAM12S) form, is expressed exclusively in regenerating and developing tissue as well as in certain cancer types. Strong ADAM12 expression levels have been noticed in the human placenta, and deregulated ADAM12S levels were associated with various pregnancy-related disorders including pre-eclampsia and intrauterine growth restriction. However, the role of ADAM12 in trophoblast motility has not been investigated so far. Hence, the present study aimed to investigate the specific function of the protease by using different primary trophoblast cell models. Immunofluorescence and Western blot analyses of first trimester placental tissue and differentiating primary first trimester cytotrophoblasts (CTBs) indicated strong upregulation of both of the ADAM12 isoforms during extravillous trophoblast differentiation. Functional assays involving short interfering RNA (siRNA)-mediated knockdown studies in primary CTBs and first trimester explant cultures revealed a significant repression of trophoblast motility upon partial loss of ADAM12. Conversely, isoform-specific overexpression in the ADAM12-negative trophoblast cell line SGHPL-5 enhanced the invasive capacity of these cells. We further confirmed proteolytic activity of trophoblast-derived ADAM12S by demonstrating its potential to degrade insulin-like growth factor-binding protein 3. Finally, we suggest that ADAM12S exerts its pro-migratory function in trophoblasts by inducing integrin beta 1-mediated cellular spreading.

Including ethical considerations in models for first-trimester screening for pre-eclampsia

Recent efforts to develop reliable and efficient early pregnancy screening programmes for pre-eclampsia have focused on combining clinical, biochemical and biophysical markers. The same model has been used for first-trimester screening for fetal aneuploidies i.e. prenatal diagnosis (PD), which is routinely offered to all pregnant women in many developed countries. Some studies suggest combining PD and pre-eclampsia screening, so women can be offered testing for a number of conditions at the same clinical visit. A combination of these tests may be practical in terms of saving time and resources; however, the combination raises ethical issues. First-trimester PD and pre-eclampsia screening entail qualitative differences which alter the requirements for disclosure, non-directedness and consent with regard to the informed consent process. This article explores the differences related to the ethical issues raised by PD and pre-eclampsia in order to elucidate which factors are relevant to deciding the type of information and consent required in each context from the perspective of the ethical principles of beneficence and autonomy. Furthermore, it argues that ensuring respect for patient autonomy is context dependent and, consequently, pre-eclampsia screening and PD should be performed independently of one another.

ISGylation: a conserved pathway in mammalian pregnancy

Successful pregnancy includes remodeling and differentiation of the endometrium in response to sex steroid hormones, development of maternal immunotolerance to the implanting embryo, and modification of the local uterine environment by the embryo to suit its own needs. The major signal released by the ruminant conceptus during establishment of pregnancy is interferon-tau (IFNT) that stimulates the expression of many genes in the endometrium and ovary. One of these genes is called interferon stimulated gene 15 (ISG15), which encodes a ubiquitin homolog with a C-terminal Gly that becomes covalently attached to Lys residues on targeted proteins through an ATP-dependent multi-step enzymatic reaction called ISGylation. The conceptus-derived induction of endometrial ISGs also occurs in mouse and human deciduas and placenta, in response to pregnancy presumably through action of cytokines such as interleukins and type I IFN. Described herein is evidence to support the concept that ISGylation is a maternal response to the developing conceptus, implantation and placentation that is conserved across mammalian pregnancy. Although the precise role for ISG15 remains elusive during pregnancy, it is clear that up-regulation in response to pregnancy may impart a pre-emptive defense to infection or other environmental insults, and protection of the conceptus against inflammatory insults across species.

A disintegrin and metalloproteinase 12 (ADAM12) localizes to invasive trophoblast, promotes cell invasion and directs column outgrowth in early placental development

During pregnancy, stromal- and vascular-remodeling trophoblasts serve critical roles in directing placental development acquiring pro-invasive characteristics. The A Disintegrin and Metalloproteinase (ADAM) family of multifunctional proteins direct cellular processes across multiple organ systems via their intrinsic catalytic, cell adhesive and intracellular signaling properties. ADAM12, existing as two distinct splice variants (ADAM12L and ADAM12S), is highly expressed in the human placenta and promotes cell migration and invasion in several tumor cell lines; however, its role in trophoblast biology is unknown. In this study, ADAM12 was localized to anchoring trophoblast columns in first trimester placentas and to highly invasive extracellular matrix-degrading trophoblasts in placental villous explants. The importance of ADAM12 in directing trophoblast invasion was tested using loss-of and gain-of-function strategies, where siRNA-directed knockdown of ADAM12 inhibited trophoblast cell invasion while over-expression promoted migration and invasion in two trophoblastic cell models. In placental villous explant cultures, siRNA-directed loss of ADAM12 significantly dampened trophoblast column outgrowth. Additionally, we provide functional evidence for the ADAM12S variant in promoting trophoblast invasion and column outgrowth through a mechanism requiring its catalytic activity. This is the first study to assign a function for ADAM12 in trophoblast biology, where ADAM12 may play a central role regulating the behavior of invasive trophoblast subsets in early pregnancy. This study also underlines the importance of ADAM12L and ADAM12S in directing cell motility in normal developmental processes outside of cancer, specifically highlighting a potentially important function of ADAM12S in directing early placental development.

Review: the ADAM metalloproteinases - novel regulators of trophoblast invasion?

During pregnancy, the extravillous trophoblast (EVT) invades the maternal decidua and remodels spiral arteries reaching as far as the inner third of the myometrium. This process is mandatory to a successful pregnancy since EVTs regulate spiral artery remodeling to achieve maximal vasodilation and thus an adequate nutrient supply to the embryo or communicate with maternal leukocyte populations to guarantee acceptance of the allogeneic conceptus. To achieve this, EVTs undergo a remarkable and unique differentiation process, which yields different phenotypes such as proliferative cell column trophoblasts or growth-arrested, invasive interstitial or endovascular cytotrophoblasts. Matrix metalloproteinases have long been seen as imperative to trophoblast invasion because of their ability to degrade extracellular matrix and therefore allow cellular movement in foreign tissues. However, global gene expression analysis reveals that EVTs also express various members of distintegrin and metalloproteinases (ADAMs). These proteases are associated with the process of proteolytic shedding and activation of surface proteins including growth factors, cytokines, receptors and their ligands rather than extracellular matrix breakdown. While ADAM12 has been associated with chromosomal abnormalities as well as preeclampsia or intrauterine fetal growth restriction, the function of ADAMs in trophoblasts remains elusive. In this article, we review the diverse invasive trophoblast phenotypes, EVT-associated protease systems and related open questions. In addition, we examine recent information about relevant ADAM members and their putative implications for EVT biology.

Can changes in angiogenic biomarkers between the first and second trimesters of pregnancy predict development of pre-eclampsia in a low-risk nulliparous patient population?

OBJECTIVE

To determine if change in maternal angiogenic biomarkers between the first and second trimesters predicts pre-eclampsia in low-risk nulliparous women.

DESIGN

A nested case-control study of change in maternal plasma soluble Flt-1 (sFlt-1), soluble endoglin (sEng) and placenta growth factor (PlGF). We studied 158 pregnancies complicated by pre-eclampsia and 468 normotensive nonproteinuric controls.

SETTING

A multicentre study in 16 academic medical centres in the USA.

POPULATION

Low-risk nulliparous women.

METHODS

Luminex assays for PlGF, sFlt-1 and sEng performed on maternal EDTA plasma collected at 9-12, 15-18 and 23-26 weeks of gestation. Rate of change of analyte between first and either early or late second trimester was calculated with and without adjustment for baseline clinical characteristics.

MAIN OUTCOME MEASURES

Change in PlGF, sFlt-1 and sEng.

RESULTS

Rates of change of PlGF, sEng and sFlt-1 between first and either early or late second trimesters were significantly different in women who developed pre-eclampsia, severe pre-eclampsia or early-onset pre-eclampsia compared with women who remained normotensive. Inclusion of clinical characteristics (race, body mass index and blood pressure at entry) increased sensitivity for detecting severe and particularly early-onset pre-eclampsia but not pre-eclampsia overall. Receiver operating characteristics curves for change from first to early second trimester in sEng, PlGF and sFlt-1 with clinical characteristics had areas under the curve of 0.88, 0.84 and 0.86, respectively, and for early-onset pre-eclampsia with sensitivities of 88% (95% CI 64-99), 77% (95% CI 50-93) and 77% (95% CI 50-93) for 80% specificity, respectively. Similar results were seen in the change from first to late second trimester.

CONCLUSION

Change in angiogenic biomarkers between first and early second trimester combined with clinical characteristics has strong utility for predicting early-onset pre-eclampsia.

Efficiency of first-trimester uterine artery Doppler, a-disintegrin and metalloprotease 12, pregnancy-associated plasma protein a, and maternal characteristics in the prediction of preeclampsia

OBJECTIVES

The purpose of this study was to estimate the efficiency of first-trimester uterine artery Doppler, A-disintegrin and metalloprotease 12 (ADAM12), pregnancy-associated plasma protein A (PAPP-A), and maternal characteristics in the prediction of preeclampsia.

METHODS

We conducted a prospective cohort study of patients presenting for first-trimester aneuploidy screening between 11 and 14 weeks' gestation. Maternal serum ADAM12 and PAPP-A levels were measured by an immunoassay, and mean uterine artery Doppler pulsatility indices were calculated. Outcomes of interest included preeclampsia, early preeclampsia (defined as requiring delivery at <34 weeks' gestation), and gestational hypertension. Logistic regression analysis was used to model the prediction of preeclampsia using ADAM12 multiples of the median (MoM), PAPP-A MoM, and uterine artery Doppler pulsatility index MoM, either individually or in combination. The sensitivity, specificity, and area under the receiver operating characteristic curves were used to compare the screening efficiency of the models using nonparametric U statistics.

RESULTS

Among 578 patients with complete outcome data, there were 54 cases of preeclampsia (9.3%) and 13 cases of early preeclampsia (2.2%). Median ADAM12 levels were significantly lower in patients who developed preeclampsia compared to those who did not (0.81 versus 1.01 MoM; P = .04). For a fixed false-positive rate of 10%, ADAM12, PAPP-A, and uterine artery Doppler parameters in combination with maternal characteristics identified 50%, 48%, and 52% of patients who developed preeclampsia, respectively. Combining these first-trimester parameters did not improve the predictive efficiency of the models.

CONCLUSIONS

First-trimester ADAM12, PAPP-A, and uterine artery Doppler characteristics are not sufficiently predictive of preeclampsia. Combinations of these parameters do not further improve their screening efficiency.

A disintegrin and metalloproteinase-12 (ADAM12): function, roles in disease progression, and clinical implications

BACKGROUND

A disintegrin and metalloproteinase-12 (ADAM12) is a member of the greater ADAM family of enzymes: these are multifunctional, generally membrane-bound, zinc proteases for which there are forty genes known (21 of these appearing in humans). ADAM12 has been implicated in the pathogenesis of various cancers, liver fibrogenesis, hypertension, and asthma, and its elevation or decrease in human serum has been linked to these and other physiological/pathological conditions.

SCOPE

In this review, we begin with a brief overview of the ADAM family of enzymes and protein structure. We then discuss the role of ADAM12 in the progression and/or diagnosis of various disease conditions, and we will conclude with an exploration of currently known natural and synthetic inhibitors.

MAJOR CONCLUSION

ADAM12 has potential to emerge as a successful drug target, although targeting the metalloproteinase domain with any specificity will be difficult to achieve due to structural similarity between the members of the ADAM and MMP family of enzymes. Overall, more research is required to establish ADAM12 being as a highly desirable biomarker and drug target of different diseases, and their selective inhibitors as potential therapeutic agents.

GENERAL SIGNIFICANCE

Given the appearance of elevated levels of ADAM12 in various diseases, particularly breast cancer, our understanding of this enzyme both as a biomarker and a potential drug target could help make significant inroads into both early diagnosis and treatment of disease.

RASSF1A in maternal plasma as a molecular marker of preeclampsia

OBJECTIVES

This study aimed to quantitate cell free (cf) and cell free fetal (cff) DNA in maternal plasma by determining RASSF1A levels before and after enzyme digestion in women who subsequently developed preeclampsia (PE) and compare them with uncomplicated pregnancies.

METHODS

Twenty-four samples from pregnant women who developed PE and 48 samples from women with uncomplicated pregnancies were analysed. Blood samples were obtained at 11-13 weeks. cfDNA was determined by quantifying RASSF1A using qRT-PCR. A second qRT-PCR was performed following methylation-sensitive enzyme digestion by BstUI, to quantitate hypermethylated RASSF1A sequences of fetal origin. ACTB gene was used as control to confirm complete enzyme digestion.

RESULTS

cfDNA and cffDNA levels were significantly increased in women who developed PE as compared with uncomplicated pregnancies (median cfDNA: 9402 vs 2698, median cffDNA: 934.5 vs 62, respectively). Following operating characteristic curve analysis, cut-off values of 7486 Εq/mL for cfDNA and 512 Εq/mL for cffDNA were chosen, which provided a sensitivity of 75% and 100% and specificity of 98% and 100%, respectively, to identify women at risk for PE.

CONCLUSIONS

The study demonstrates potential use of cfDNA and cffDNA in maternal plasma as markers for the early prediction of women at risk for PE.

First-trimester prediction of preterm birth using ADAM12, PAPP-A, uterine artery Doppler, and maternal characteristics

OBJECTIVE

The objective of this study was to estimate the efficiency of first-trimester a disintegrin and metalloprotease 12 (ADAM12), pregnancy-associated plasma protein A (PAPP-A), uterine artery Doppler, and maternal characteristics in the prediction of preterm birth (PTB).

METHODS

This was a prospective cohort study of patients presenting for first-trimester aneuploidy screening. Maternal serum ADAM12 and PAPP-A levels were measured by immunoassay, and mean uterine artery Doppler pulsatility indices were calculated. The primary outcome was PTB <34 weeks' gestation, and the secondary outcome was PTB <37 weeks' gestation. Logistic regression was used to model the prediction of PTB using ADAM12, PAPP-A, uterine artery Doppler, and maternal characteristics, individually and in combination. Sensitivity, specificity, and area under the receiver-operating characteristic curves were compared between models.

RESULTS

Of 578 patients, 36 (6.2%) delivered <34 weeks, and 78 (13.5%) delivered <37 weeks. For a 20% fixed false positive rate, ADAM12, PAPP-A, and uterine artery Doppler identified 58%, 52%, and 62% of patients with PTB <34 weeks and 42%, 48%, and 50% of patients with PTB <37 weeks, respectively. Combining these first-trimester parameters did not improve the predictive efficiency of the models.

CONCLUSION

First-trimester ADAM12, PAPP-A, and uterine artery Doppler are each modestly predictive of PTB; however, combinations of these parameters do not further improve their screening efficiency.

First-trimester prediction of preeclampsia in nulliparous women at low risk

OBJECTIVE

To identify clinical characteristics and biochemical markers in first-trimester samples that would possibly predict the subsequent development of preeclampsia.

METHODS

We conducted a multicenter observational study in 2,434 nulliparous women at low risk to identify biomarkers that possibly predict preeclampsia. Clinical history, complete blood count, and biochemical markers were assessed in the first trimester. The trophoblast and angiogenesis markers ADAM-12, pregnancy-associated plasma protein-A, placental protein 13, placental growth factor, soluble fms-like tyrosine kinase-1, and endoglin were measured in a case-control subset of 174 women with preeclampsia and 509 women in the control group.

RESULTS

Univariable analysis revealed maternal age, race, marital status, years of education, source of medical payment, prenatal caregiver, body mass index (BMI, calculated as weight (kg)/[height (m)]), and systolic blood pressure at enrollment were significantly associated with preeclampsia. Mean platelet volume was greater at enrollment in women who later had development of preeclampsia (median 9.4 compared with 9.0 femtoliter (fl); P=.02). First-trimester concentrations (multiples of the median) of ADAM-12 (1.14 compared with 1.04; P=.003), pregnancy-associated plasma protein-A (0.94 compared with 0.98; P=.04), and placental growth factor (0.83 compared with 1.04; P<.001) were significantly different in women who had development of preeclampsia compared with women in the control group. The optimal multivariable model included African American race, systolic blood pressure, BMI, education level, ADAM-12, pregnancy-associated plasma protein-A, and placental growth factor, and yielded an area under the curve of 0.73 (95% confidence interval 0.69-0.77) and a sensitivity of 46.1% (95% confidence interval 38.3-54.0) for 80% specificity.

CONCLUSION

A multivariable analysis of clinical data and biochemical markers in the first trimester did not identify a model that had clinical utility for predicting preeclampsia in a nulliparous population at low risk.

LEVEL OF EVIDENCE

II.

The value of early second trimester PAPP-A and ADAM12 in screening for pre-eclampsia

OBJECTIVE

To estimate the pre-eclampsia screening performance of PAPP-A (pregnancy-associated plasma protein-A) and ADAM12 (A Disintegrin And Metalloprotease 12) in the early second trimester of pregnancy.

METHODS

Stored frozen serum samples from a previously published nested case-control study comprising 77 women who developed pre-eclampsia and 224 unaffected controls were thawed and assayed for PAPP-A and ADAM12. Levels were converted into multiple of the unaffected median (MoM) values.

RESULTS

Neither PAPP-A or ADAM12 were significantly different in women who developed pre-eclamspia compared with unaffected controls (PAPP-A: 0.97 MoM [95% confidence interval 0.73 to 1.25], ADAM12: 1.01 MoM [0.91 to 1.13]).

CONCLUSION

Our results do not support the use of PAPP-A or ADAM12 in early second trimester antenatal screening for pre-eclampsia.

Differential Expression of HrtA1 and ADAM12 in Placentas from Preeclamptic and Normotensive Pregnancies

BACKGROUND

High temperature requirement factor A 1 (HtrA1) and a disintegrin and metalloproteinase 12 (ADAM12), which play roles in placental implantation and placental growth, have been implicated in the pathogenesis of preeclampsia.

METHODS

We investigated relative mRNA expression of both genes in placental tissues from women with preeclampsia (N=18) (average gestational age 36 weeks) and an equal number of women with normotensive pregnancies (average gestational age 39 weeks). Real-time polymerase chain reaction was used to measure mRNA extracted from term placental biopsies. Differential gene expression was evaluated using Student's T-test and fold change analyses.

RESULTS

Statistically significant increases in placental HtRA1 (1.69-fold, p=0.030) and ADAM12 (1.48-fold, p=0.010) mRNA expression were observed among preeclamptic cases as compared with normotensive controls. HtrA1 expression was correlated with maternal age (p-value <0.01) among preeclampsia cases.

CONCLUSION

Increases in HtRA1 and ADAM12 placental gene expression in placentas from preeclamptic pregnancies are consistent with some earlier reports of altered serum protein concentrations in preeclamptic pregnancies. This adds to the literature suggesting that defects in placentation (e.g. involving trophoblast invasion) are of etiologic importance in preeclampsia.

Evaluation of 7 serum biomarkers and uterine artery Doppler ultrasound for first-trimester prediction of preeclampsia: a systematic review

Preeclampsia (PE) affects 1% to 2% of pregnant women and is a leading cause of maternal and perinatal morbidity and mortality worldwide. The clinical syndrome of PE arises in the second half of pregnancy. However, many underlying factors including defective placentation may already be apparent in the first and early second trimester in many patients. In clinical practice, there is currently no reliable screening method in the first trimester of pregnancy with sufficient accuracy to identify women at high risk to develop PE. Early identification of high-risk pregnancy may facilitate the development of new strategies for antenatal surveillance or prevention and thus improve maternal and perinatal outcome. The aim of this systematic review was to study the literature on the predictive potential of first-trimester serum markers and of uterine artery Doppler velocity waveform assessment (Ut-A Doppler). Literature on the 7 most studied serum markers (ADAM12, fβ-hCG, Inhibin A, Activin A, PP13, PlGF, and PAPP-A) and Ut-A Doppler was primarily selected. In the selected literature, a combination of these markers was analyzed, and where relevant, the value of maternal characteristics was added. Measurements of serum markers and Ut-A Doppler were performed between week 8 + 0 and 14 + 0 GA. Low levels of PP13, PlGF, and PAPP-A and elevated level of Inhibin A have been found to be significantly associated with the development of PE later in pregnancy. The detection rates of single markers, fixed at 10% false-positive rate, in the prediction of early-onset PE were relatively low, and ranged from 22% to 83%. Detection rates for combinations of multiple markers varied between 38% and 100%. Therefore, a combination of multiple markers yields high detection rates and is promising to identify patients at high risk of developing PE. However, large scale prospective studies are required to evaluate the power of this integrated approach in clinical practice.

TARGET AUDIENCE

Obstetricians and Gynecologists, Family physicians Learning Objectives: After completion of this article, the reader should be better able to appraise the recent literature on the development of preeclampsia in the first-trimester, evaluate the predictive value of first-trimester markers and use first-trimester markers, either individually or in combination, to assess the risk of preeclampsia.

Screening for pre-eclampsia--lessons from aneuploidy screening

BACKGROUND

Antenatal screening for aneuploidy is an established routine clinical practice worldwide. The same statistical methodology, developed and refined over three decades, might be adapted to screening for pre-eclampsia.

METHODS

The published literature is reviewed for evidence that the methodology is valid for pre-eclampsia using first trimester maternal serum PP13, PAPP-A, PlGF, ADAM12 and inhibin A, together with MAP and uterine artery Doppler PI. Risk is estimated for both early onset pre-eclampsia, requiring delivery before 34 weeks, or late onset disease. Prior risk from the background prevalence multiplied by likelihood ratios (LRs) for ethnicity, parity, adiposity and family history is multiplied by an LR from the screening marker profile. Markers are expressed in multiples of the gestation-specific median and adjusted for body mass, ethnicity and smoking status as appropriate. A standardized population with a fixed distribution of risk factors and a multi-variate Gaussian model of marker profiles is used to predict performance.

RESULTS

There is sufficient published data to estimate individual risks reasonably well. Modeling predicts that using PAPP-A and one other serum marker, together with the physical markers more than two-thirds of early and one-third of late onset cases can be detected by classifying less than 2% of pregnancies as high risk; three-quarters of early case could be detected with a 5% high risk rate.

CONCLUSION

Whilst more data on some markers is still required modeling so far suggests that extending first trimester aneuploidy screening programs to include pre-eclampsia screening would yield a high detection. However, prospective studies are needed to verify the model predictions.

Von Willebrand factor and ADAMTS13: a candidate couple for preeclampsia pathophysiology

OBJECTIVE

The goal of this study was to search for an association between a desintegrin-like and metalloprotease thrombospondin type 1 motif, member 13 (ADAMTS13) levels and the occurrence of preeclampsia, its characteristics (time-onset and severity), and its consequences (occurrence of fetal growth restriction or preterm delivery).

METHODS AND RESULTS

We studied 140 pairs of women in a case-control study with 3 matching criteria: maternal age, gestational age, and ethnic origin. We measured ADAMTS13 activity using a fluorescence resonance energy transfer assay with the fluorescence resonance energy transfer-VWF73 peptide. ELISA was used to assess protein antigen levels: ADAMTS13, von Willebrand Factor (VWF), interleukin-6, C-reactive protein, P-selectin, and thrombospondin-1. The lowest levels of ADAMTS13 (activity ≤ 70% or antigen ≤ 592 ng/mL) were significantly associated with preeclampsia (odds ratios [OR] [95% confidence interval] of 4.2 [1.1 to 15] and 14.3 [1.7 to 123], respectively). This association was independent of VWF levels and preeclampsia risk factors but dependent on interleukin-6 and C-reactive protein levels for ADAMTS13 activity. Levels of ADAMTS13 activity (≤ 57%) were significantly associated with early-onset preeclampsia (OR = 2.5 [1.1 to 5.8]). Severe preeclampsia was associated with the highest levels of P-selectin (>57 ng/mL) (OR = 3.4 [1.2 to 9.7]).

CONCLUSIONS

Preeclampsia is associated with decreased levels of ADAMTS13, independently of VWF. This decrease is quantitative, occurs early, and seems to be dependent on inflammation. Our results suggest that ADAMTS13 could participate in the pathophysiology of preeclampsia.

Regulation of pregnancy-associated plasma protein A2 (PAPPA2) in a human placental trophoblast cell line (BeWo)

BACKGROUND

Pregnancy-associated plasma protein A2 (PAPPA2) is an insulin-like growth factor-binding protein (IGFBP) protease expressed at high levels in the placenta and upregulated in pregnancies complicated by preeclampsia and HELLP (Hemolytic anemia, Elevated Liver enzymes, and Low Platelet count) syndrome. However, it is unclear whether elevated PAPPA2 expression causes abnormal placental development, or whether upregulation compensates for placental pathology. In the present study, we investigate whether PAPPA2 expression is affected by hypoxia, oxidative stress, syncytialization factors or substances known to affect the expression of PAPPA2's paralogue, PAPPA.

METHODS

BeWo cells, a model of placental trophoblasts, were treated with one of the following: hypoxia (2% O2), oxidative stress (20 microM hydrogen peroxide), forskolin (10 microM and 100 microM), TGF-beta (10 and 50 ng/mL), TNF-alpha (100 ng/mL), IL-1beta (100 ng/mL) or PGE2 (1 microM). We used quantitative RT-PCR (qRT-PCR) to quantify the mRNA levels of PAPPA2, as well as those of PAPPA and ADAM12 since these proteases have similar substrates and are also highly expressed in the placenta. Where we observed significant effects on PAPPA2 mRNA levels, we tested for effects at the protein level using an in-cell Western assay.

RESULTS

Hypoxia, but not oxidative stress, caused a 47-fold increase in PAPPA2 mRNA expression, while TNF-alpha resulted in a 6-fold increase, and both of these effects were confirmed at the protein level. PGE2 resulted in a 14-fold upregulation of PAPPA2 mRNA but this was not reflected at the protein level. Forskolin, TGF-beta and IL-1beta had no significant effect on PAPPA2 mRNA expression. We observed no effects of any treatment on PAPPA or ADAM12 expression.

CONCLUSION

Our study demonstrates that factors previously known to be highly expressed in preeclamptic placentae (PGE2 and TNF-alpha), contribute to the upregulation of PAPPA2. Hypoxia, known to occur in preeclamptic placentae, also increased PAPPA2 expression. These results are consistent with the hypothesis that PAPPA2 is upregulated as a consequence of placental pathology, rather than elevated PAPPA2 levels being a cause of preeclampsia.

A disintegrin and metalloprotease protein-12 as a novel marker for the diagnosis of ectopic pregnancy

OBJECTIVE

To evaluate the performance of a novel biomarker, a disintegrin and metalloprotease-12 (ADAM-12), to differentiate an ectopic pregnancy (EP) from normal intrauterine pregnancies (IUPs).

DESIGN

Case-control study.

SETTING

Three urban academic centers.

PATIENT(S)

Women who were seen in the emergency department with pain or bleeding in the first trimester of pregnancy.

INTERVENTION(S)

Sera from women with diagnosed EP or IUP were evaluated via proteomics and an ADAM-12 dissociation-enhanced lanthanide fluoroimmunoassay.

MAIN OUTCOME MEASURE(S)

Differences between groups, area under the receiver operating curve, sensitivity, and specificity.

RESULT(S)

Via a proteomics evaluation, we found a statistically significant decrease in ADAM-12 in the sera of patients with EP, which we confirmed in a larger group of 199 patients (median IUP 18.6 ng/mL versus median EP 2.5 ng/mL with good discrimination between the groups as assessed by receiver operating characteristics [area under the curve = 0.82]). At a low cut-point, the sensitivity was 70% and specificity 84%, but, at a higher cut-point optimizing sensitivity, the ADAM-12 test demonstrated a sensitivity of 97%.

CONCLUSION(S)

ADAM-12 is a promising marker for the diagnosis of EP in women with symptoms in the first trimester, validating the proteomics findings. Further studies in additional patient populations and in combination with other biomarkers are needed.

The role of serum markers and uterine artery Doppler in identifying at-risk pregnancies

Measures of placental dysfunction, including maternal serum analytes and Doppler studies, have been linked to adverse pregnancy outcomes, although the predictive ability of any single one is poor. Improved knowledge of the multifactorial nature of many of the adverse outcomes of pregnancy has sparked interest in the use of multi-parameter models that combine maternal serum analytes with measures of placental structure and blood flow. The combination of various first-trimester and second-trimester analytes and uterine artery Doppler screening show promise as potential screening tools, but large prospective studies are needed to further define their role in clinical practice.

Complex patterns of ADAM12 mRNA and protein splice variants in the human placenta

AIMS

Trophoblast fusion in the placenta is prerequisite to successful pregnancy and the pathological conditions related to it. The presence of syncytin-1, is not sufficient to explain the complete event and ADAM12 is a major co-player candidate. Via differential splicing, the ADAM12 gene produces a short and a long form, being the ADAM12-S and the ADAM12-L respectively.

METHODS AND RESULTS

We investigated the localisation of both variants in the human placenta using whole mount in situ hybridisation, immunohistochemistry and Northern blotting in 1st (n=8) and 3rd (n=8) trimester placentae and in the case of NB in several cell lines. In Northern blotting, 1st and 3rd trimester placentae were positive for the ADAM12-S and Bewo, 293HEK, JAR, leucocytes, macrophages, 1st and 3rd trimester placentae were positive for ADAM12-L. In whole mount in situ hybridisation, the 1st and 3rd trimester placental syncytium was positive for both variants. In immunohistochemistry, ADAM12-L localised in the cytotrophoblast of both 1st and 3rd trimester placentae, while ADAM12-S localised in the complete syncytium, often including the cytotrophoblast.

CONCLUSION

The different localisation of ADAM12-S and ADAM12-L indicates a possible different role making ADAM12-L a candidate for the fusion event, while the syncytial localisation of the ADAM12-S makes it a candidate for cell-cell and cell-matrix interactions between the placental syncytium and the maternal interface.

First-trimester placental protein 13 and placental growth factor: markers for identification of women destined to develop early-onset pre-eclampsia

OBJECTIVE

 To investigate the predictive value of maternal serum pregnancy-associated plasma protein A (PAPP-A), free β subunit of human chorionic gonadotrophin (fβ-hCG), placental protein 13 (PP13), placental growth factor (PlGF) and a desintegrin and metalloproteinase 12 (ADAM12), for first-trimester identification of early-onset pre-eclampsia.

DESIGN

  Nested case-control study.

SETTING

  Routine first-trimester screening for trisomy 21 in the Netherlands.

POPULATION

  Eighty-eight women who developed pre-eclampsia or haemolysis, elevated liver enzymes, low platelets (HELLP) syndrome before 34 weeks of gestation and 480 controls.

METHODS

  PP13, PlGF and ADAM12 were measured in stored first-trimester serum, previously tested for PAPP-A and fβ-hCG. All marker levels were expressed in multiples of the gestation-specific normal median (MoMs). Model predicted detection rates for fixed false-positive rates were obtained for statistically significant markers alone and in combination.

MAIN OUTCOME MEASURES

  Development of pre-eclampsia or HELLP syndrome.

RESULTS

 PP13 and PlGF were reduced in women with pre-eclampsia, with medians 0.68 MoM and 0.73 MoM respectively (P < 0.0001 for both). PAPP-A was reduced (median 0.82 MoM, P < 0.02) whereas ADAM12 and fβ-hCG did not differ between control women and those with pre-eclampsia. In pre-eclampsia complicated by a small-for-gestational-age fetus, all markers except fβ-hCG had lower values, compared with pregnancies involving fetuses of normal weight. The model-predicted pre-eclampsia detection rate for a combination of PP13 and PlGF was 44% and 54%, respectively, for a fixed 5% and 10% false-positive rate.

CONCLUSION

 This study demonstrates that PP13 and PlGF in the first-trimester might be promising markers in risk assessment for early pre-eclampsia/HELLP syndrome but for an adequate screening test additional characteristics are necessary.