Potential markers of preeclampsia--a review

Clinical syndromes associated with acquired antithrombin deficiency via microvascular leakage and the related risk of thrombosis

Antithrombin (AT) is a 65kDa glycoprotein belonging to a group of inhibitory factors known as serpins (serine protease inhibitors). It plays a critical role in the inhibition of coagulation and inflammation processes within the environment of the vascular endothelium. Inadequate levels of functional AT in plasma results in an increased risk of thrombotic events, both venous and arterial. AT deficiency can be inherited or acquired. Congenital AT deficiency is the most severe inherited thrombophilic condition with an odds ratio of 20 for the increased risk of venous thrombosis. Acquired AT deficiency occurs in a variety of physiologic and pathologic medical conditions with similar risks of increased thrombosis. In this article, we review clinical settings characterized by an acquired AT deficiency largely or partly subsequent to protein microvascular leakage. Other different mechanisms of AT depletion are implied in some clinical conditions together with endothelial loss, and, therefore, outlined. In addition, we provide a description of the current knowledge on the specific mechanisms underlying endothelial AT leakage and on the consequences of this protein decrease, specifically looking at thrombosis. We identify potential directions of research that might prove useful in patients with acquired AT deficiency.

Targeted gene analysis: increased B-cell lymphoma 6 in preeclamptic placentas

Preeclampsia is a leading cause for maternal and perinatal mortality and morbidity. Microarray-based transcriptional profiling has been widely used for identifying genes responsible for preeclampsia. These studies deliver multiple pictures of gene signatures, implying the complicated pathophysiology. In the present work, we designed our own gene array containing genes involved in various signaling transduction pathways and analyzed placental samples from patients with preeclampsia and controls. We verify that genes associated with angiogenesis and migration pathways are mostly altered in preeclamptic placentas. Interestingly, several genes including B-cell lymphoma 6 have been identified to be linked to preeclampsia. Increased expression of B-cell lymphoma 6 is correlated with enhanced FLT1 and LEPTIN, the hallmarks of preeclampsia. Moreover, the protein level of B-cell lymphoma 6 is elevated in preeclamptic placentas and is predominantly localized in the nucleus of villous cytotrophoblasts lying directly underneath the syncytial layer, suggestive of an involvement in the function of villous trophoblasts. Altered B-cell lymphoma 6, a key oncogene in B-cell lymphomagenesis, may be involved in the pathogenesis of preeclampsia, and further investigations are required to decipher the molecular mechanisms.

Transthyretin as a novel candidate biomarker for preeclampsia

Preeclampsia (PE) is considered to be a potentially fatal complication during pregnancy. However, no effective laboratory assessment has been developed to enable early diagnosis and monitoring of PE. The present study aimed to identify differentially expressed transthyretin (TTR) during severe PE and evaluate TTR as a possible biomarker of this disease. TTR levels were determined in the different gestational weeks of normal pregnancy (before 20 weeks, n=41; after 20 weeks, n=39) using enzyme-linked immunosorbent assay (ELISA). TTR concentrations in pregnant females with severe PE (n=43) were compared with those in healthy matched control subjects (n=37) using western blot analysis and ELISA. The median TTR concentration during severe PE in each month of gestation was significantly lower than the concentrations recorded during normal pregnancy. TTR levels in females with severe PE were significantly downregulated compared with the control subjects (P<0.001; area under the curve, 0.834-0.967). Thus, TTR may be used as a potential biomarker of PE.

KE and EE genotypes of ICAM-1 gene K469E polymorphism is associated with severe preeclampsia

BACKGROUND

Preeclampsia (PE) is one of the most important complications of pregnancy that is associated with significant mortality and morbidity in mother and fetus. Since the etiologic factors in its development are still unclear, we aimed to examine the intercellular adhesion molecule-1 (ICAM-1) gene K469E polymorphism in preeclamptic and control healthy women.

MATERIALS AND METHODS

Genetic polymorphism was analyzed in 192 PE and 186 healthy control women. PCR-RFLP method was used to identify K469E polymorphism.

RESULTS

The frequency of KK, KE, and EE genotypes of ICAM-1 gene was not different between PE patients and healthy pregnant women. Whereas, the frequency of KE and EE genotypes was significantly higher in severe PE than mild PE women and control group, and the risk of severe PE was 2.4-fold higher in subjects with KE genotype (OR, 2.4 [95% CI, 1 to 5.9]; P = 0.03) and 3.3-fold higher in subjects with EE genotype (OR, 3.3 [95% CI, 1.2 to 9]; P = 0.015) compared to individuals with KK genotype.

CONCLUSION

We concluded that KE and EE genotypes of K469E polymorphism could increase risk of severe PE.

Gestational diabetes and hypertensive disorders of pregnancy as vascular risk signals: an overview and grading of the evidence

The occurrence of common pregnancy-related medical disorders identifies women at high risk of developing future vascular disease. Systematic reviews of cohort studies demonstrate that gestational diabetes confers a 7-fold risk increase for type 2 diabetes, and preeclampsia confers a 1.8-fold risk increase for type 2 diabetes and 3.4-fold risk increase for hypertension. Gestational diabetes and hypertensive disorders of pregnancy (HDP) increase the risk of premature vascular disease, but the 2-fold risk increase associated with preeclampsia is only partially explained by the development of traditional vascular risk factors. Despite the compelling evidence for gestational diabetes and HDP as vascular risk indicators, there are no published Canadian vascular prevention guidelines that recognize these postpartum women. In contrast, the 2011 American Heart Association guidelines on cardiovascular disease in women include gestational diabetes and HDP in their vascular risk assessment. Studies indicate that the importance surveillance of vascular risk factors in these women after pregnancy is underappreciated by the women themselves and their physicians. Although a prudent diet and physically active lifestyle were demonstrated to reduce diabetes risk in women with a gestational diabetes history in the American Diabetes Prevention Program trial, adoption of these health behaviours is low; qualitative studies confirm a need for tailored strategies that address barriers and provide social support. Further research is also needed on approaches to reduce vascular risk in women with a history of gestational diabetes and HDP. Otherwise, an early window of opportunity for chronic disease prevention in young, high-risk women will be missed.

PAPPA2 is increased in severe early onset pre-eclampsia and upregulated with hypoxia

Severe early onset pre-eclampsia is a serious pregnancy complication, believed to arise as a result of persistent placental hypoxia due to impaired placentation. Pregnancy-associated plasma protein A2 (PAPPA2) is very highly expressed in the placenta relative to all other tissues. There is some evidence that PAPPA2 mRNA and protein are increased in association with pre-eclampsia. The aim of the present study was to characterise the mRNA and protein expression, as well as localisation, of PAPPA2 in an independent cohort of severe early onset pre-eclamptic placentas. We also examined whether exposing placental explants to hypoxia (1% oxygen) changed the expression of PAPPA2. Expression of PAPPA2 mRNA and protein was upregulated in severe early onset pre-eclamptic placentas compared with preterm controls and localised to the syncytiotrophoblast. Interestingly, protein localisation was markedly reduced in term placenta. Syncytialisation of BeWo cells did not change PAPPA2 expression. However, hypoxia upregulated PAPPA2 mRNA and protein expression in primary placental explants. Together, our data suggest that PAPPA2 may be upregulated in severe pre-eclampsia and, functionally, this may be mediated via increased placental hypoxia known to occur with this pregnancy disorder.

New directions in the prediction of pre-eclampsia

Pre-eclampsia remains an important worldwide cause of maternal and perinatal morbidity and mortality. Improved prediction of those destined to develop this condition would allow for timely initiation of prophylactic therapy, appropriate antenatal surveillance and better targeted research into preventive interventions. This paper reviews recent research into strategies for the prediction of pre-eclampsia, including the use of maternal risk factors, mean maternal arterial pressure, ultrasound parameters and biomarkers. The most promising strategies involve multiparametric approaches, which use a variety of individual parameters in combination, as has been established in first-trimester aneuploidy screening. The paper concludes with a discussion of the issues around the introduction of such testing into clinical practice.

Evaluation of current and new biomarkers in severe preeclampsia: a microarray approach reveals the VSIG4 gene as a potential blood biomarker

Preeclampsia is a placental disease characterized by hypertension and proteinuria in pregnant women, and it is associated with a high maternal and neonatal morbidity. However, circulating biomarkers that are able to predict the prognosis of preeclampsia are lacking. Thirty-eight women were included in the current study. They consisted of 19 patients with preeclampsia (13 with severe preeclampsia and 6 with non-severe preeclampsia) and 19 gestational age-matched women with normal pregnancies as controls. We measured circulating factors that are associated with the coagulation pathway (including fibrinogen, fibronectin, factor VIII, antithrombin, protein S and protein C), endothelial activation (such as soluble endoglin and CD146), and the release of total and platelet-derived microparticles. These markers enabled us to discriminate the preeclampsia condition from a normal pregnancy but were not sufficient to distinguish severe from non-severe preeclampsia. We then used a microarray to study the transcriptional signature of blood samples. Preeclampsia patients exhibited a specific transcriptional program distinct from that of the control group of women. Interestingly, we also identified a severity-related transcriptional signature. Functional annotation of the upmodulated signature in severe preeclampsia highlighted two main functions related to “ribosome” and “complement”. Finally, we identified 8 genes that were specifically upmodulated in severe preeclampsia compared with non-severe preeclampsia and the normotensive controls. Among these genes, we identified VSIG4 as a potential diagnostic marker of severe preeclampsia. The determination of this gene may improve the prognostic assessment of severe preeclampsia.

A multi-centre phase IIa clinical study of predictive testing for preeclampsia: improved pregnancy outcomes via early detection (IMPROvED)

BACKGROUND

5% of first time pregnancies are complicated by pre-eclampsia, the leading cause of maternal death in Europe. No clinically useful screening test exists; consequentially clinicians are unable to offer targeted surveillance or preventative strategies. IMPROvED Consortium members have pioneered a personalised medicine approach to identifying blood-borne biomarkers through recent technological advancements, involving mapping of the blood metabolome and proteome. The key objective is to develop a sensitive, specific, high-throughput and economically viable early pregnancy screening test for pre-eclampsia.

METHODS/DESIGN

We report the design of a multicentre, phase IIa clinical study aiming to recruit 5000 low risk primiparous women to assess and refine innovative prototype tests based on emerging metabolomic and proteomic technologies. Participation involves maternal phlebotomy at 15 and 20 weeks' gestation, with optional testing and biobanking at 11 and 34 weeks. Blood samples will be analysed using two innovative, proprietary prototype platforms; one metabolomic based and one proteomic based, both of which outperform current biomarker based screening tests at comparable gestations. Analytical and clinical data will be collated and analysed via the Copenhagen Trials Unit.

DISCUSSION

The IMPROvED study is expected to refine proteomic and metabolomic panels, combined with clinical parameters, and evaluate clinical applicability as an early pregnancy predictive test for pre-eclampsia. If 'at risk' patients can be identified, this will allow stratified care with personalised fetal and maternal surveillance, early diagnosis, timely intervention, and significant health economic savings. The IMPROvED biobank will be accessible to the European scientific community for high quality research into the cause and prevention of adverse pregnancy outcome.

TRIAL REGISTRATION

Trial registration number NCT01891240The IMPROvED project is funded by the seventh framework programme for Research and Technological development of the EU. http://www.fp7-improved.eu/

Function of survivin in trophoblastic cells of the placenta

BACKGROUND

Preeclampsia is one of the leading causes of maternal and perinatal mortality and morbidity worldwide and its pathogenesis is not totally understood. As a member of the chromosomal passenger complex and an inhibitor of apoptosis, survivin is a well-characterized oncoprotein. Its roles in trophoblastic cells remain to be defined.

METHODS

The placental samples from 16 preeclampsia patients and 16 well-matched controls were included in this study. Real-time PCR, immunohistochemistry and Western blot analysis were carried out with placental tissues. Primary trophoblastic cells from term placentas were isolated for Western blot analysis. Cell proliferation, cell cycle analysis and immunofluorescence staining were performed in trophoblastic cell lines BeWo, JAR and HTR-8/SVneo.

RESULTS

The survivin gene is reduced but the protein amount is hardly changed in preeclamptic placentas, compared to control placentas. Upon stress, survivin in trophoblastic cells is phosphorylated on its residue serine 20 by protein kinase A and becomes stabilized, accompanied by increased heat shock protein 90. Depletion of survivin induces chromosome misalignment, abnormal centrosome integrity, and reduced localization and activity of Aurora B at the centromeres/kinetochores in trophoblastic metaphase cells.

CONCLUSIONS

Our data indicate that survivin plays pivotal roles in cell survival and proliferation of trophoblastic cells. Further investigations are required to define the function of survivin in each cell type of the placenta in the context of proliferation, differentiation, apoptosis, angiogenesis, migration and invasion.

Urinary inositol phosphoglycan-P type: near patient test to detect preeclampsia prior to clinical onset of the disease. A study on 416 pregnant Mauritian women

Preeclampsia and eclampsia account for major pregnancy complications in Mauritius, an emerging country (maternal mortality rate of 60 per 100,000 deliveries). This prospective longitudinal study was carried out in the main regional hospital in the north of the island, to measure inositol phosphoglycan-P type (IPG-P) in the urine of pregnant women (using an ELISA-based assay). Women had approximately 10 prenatal visits per pregnancy and a complete follow-up in this same referral centre after the first trimester of pregnancy. Urine samples were collected every 1-4 weeks in all women. In a cohort of 416 patients, preeclampsia (PE) was diagnosed in 34 women. In established PE (hypertension and proteinuria), the assay as a diagnostic test showed a positive likelihood ratio of 18.73, a negligible negative likelihood ratio with area under the curve (AUC) of 0.99, sensitivity of 96.7%, specificity of 94.8% and remained negative in control women (n=312), women with gestational hypertension (without proteinuria (n=56), and gestational diabetic mothers (n=14). Moreover, as a predictive screening test two weeks before the diagnosis of PE, the assay showed sensitivity of 84.2% and specificity of 83.6%. Detection of urinary inositol phosphoglycan-P type in pregnant women can be a useful confirmatory marker of PE, as well as a predictive marker, two weeks before the onset of the disease.

If we know so much about preeclampsia, why haven't we cured the disease?

Preeclampsia has been recognized for at least 100 years. In the last 20 years, the consideration of the disorder as more than simply hypertension in pregnancy has led to an explosion in knowledge about preeclampsia pathophysiology. It is now evident that for most cases of preeclampsia, the root cause is the placenta. Relatively reduced placental perfusion leads to inflammation, oxidative stress, and endoplasmic reticulum stress, which converge to modify maternal physiology, with endothelium an important target. Although preeclampsia is characteristically diagnosed in the last third of pregnancy, it is evident that many of these pathophysiological changes can be detected long before clinically evident disease. Furthermore, it is evident that the "maternal constitution," including genetic, behavioral, and metabolic factors, influences the maternal response to the abnormal placentation of preeclampsia. These insights would seem to provide a guide for the prediction of the disorder in early pregnancy, along with targets for intervention. However, this has not been the case. Predictive tests guided by this knowledge do not predict well and several interventions guided by the expanded understanding of pathophysiology do not prevent the disease. We propose that these failures are secondary to the fact that preeclampsia is more than one disorder. Further, we suggest that future progress toward prediction and prevention will require research guided by this concept.

Presence of auto-antibody against two placental proteins, annexin A1 and vitamin D binding protein, in sera of women with pre-eclampsia

Pre-eclampsia (PE) is one of the most complex and life-threatening pregnancy disorders. PE is characterized by maternal hypertension and proteinuria. There is much evidence to support an immunological etiology for PE and auto-immunity is considered a predisposing factor for PE. The aim of the present study was the investigation of placental proteins as targets for auto-antibodies in PE patients. 2D-PAGE technique was used for separation of the total human placental proteins. After separation, protein spots were transferred to the PVDF membranes and blotted with sera from 20 PE patients and compared with membranes blotted with 20 sera from normal women. MALDI TOF/TOF mass spectrometry technique was used for identification of differentially blotted spots. Moreover, the results of mass analysis were confirmed using western blot with commercial mAbs and RT-PCR technique. The results indicated that two placental proteins, annexin A1 and vitamin D binding protein (DBP), might be targeted by PE sera. The expression of annexin A1 and DBP was also confirmed at RNA level using the RT-PCR technique. Furthermore, the mass results were confirmed by western blotting with commercial mAbs against two targeted proteins. The data of the present study suggest two new placental proteins, annexin A1 and DBP, as placental immune targets. Considering the relation among vitamin D deficiency, increased risk of PE, and the role of annexin A1 in the resolution of inflammation, production of antibody against annexin A1 and DBP may be considered a new auto-immune hypothesis in pre-eclampsia that calls for further investigation in future work.

Biomarkers for the management of pre-eclampsia in pregnant women

Pre-eclampsia (PE) is a pregnancy related disorder characterized by hypertension and proteinuria noticeable after 20 wk of gestation. It is a leading cause of maternal and foetal mortality and morbidity worldwide. The aetiology of the disease is unknown, but recent studies have revealed that this disorder appears to originate in placenta and is characterized by widespread maternal endothelial dysfunction. Till date, delivery of placenta is the only cure for the disease. So, there is a need for the identification of highly specific and sensitive biochemical markers that would allow early identification of patients at risk and thus help in providing proper prenatal care. Several promising biomarkers have been proposed, alone or in combination, that may help in predicting women who are likely to develop PE. Maternal serum concentrations of these biomarkers either increase or decrease in PE during gestation. This review focuses on the various biomarkers available and their utility in predicting pre-eclampsia.

Differential regulation of brain-derived neurotrophic factor in term and preterm preeclampsia

Our earlier studies in preeclampsia (PE) suggest a causal relationship between altered angiogenic factors and birth outcomes. Recent studies suggest that brain-derived neurotrophic factor (BDNF) can stimulate angiogenesis. The present study examines the levels of maternal and cord BDNF in women with PE (n = 106; full term [n = 60] and preterm [n = 46]) and normotensive women (n = 95; control) delivering at term. Maternal BDNF levels were lower (P < .05) in women with PE when compared to normotensive women. Cord BDNF levels were higher (P < .01) in women with PE delivering at term, while it was lower (P < .01) in women delivering preterm. Maternal BDNF levels were negatively associated with systolic and diastolic blood pressure (P < .01 for both). Our data for the first time suggest a possible role for BDNF in the pathophysiology of PE. Differential regulation of cord BDNF levels in preterm PE suggests a need to follow-up children to assess the neurodevelopmental effects in later life.

Differentially expressed microRNAs and affected biological pathways revealed by modulated modularity clustering (MMC) analysis of human preeclamptic and IUGR placentas

INTRODUCTION

This study focuses on the implementation of modulated modularity clustering (MMC) a new cluster algorithm for the identification of molecular signatures of preeclampsia and intrauterine growth restriction (IUGR), and the identification of affected microRNAs

METHODS

Eighty-six human placentas from normal (40), growth-restricted (27), and preeclamptic (19) term pregnancies were profiled using Illumina Human-6 Beadarrays. MMC was utilized to generate modules based on similarities in placental transcriptome. Gene Set Enrichment Analysis (GSEA) was used to predict affected microRNAs. Expression levels of these candidate microRNAs were investigated in seventy-one human term placentas as follows: control (29); IUGR (26); and preeclampsia (16).

RESULTS

MMC identified two modules, one representing IUGR placentas and one representing preeclamptic placentas. 326 differentially expressed genes in the module representing IUGR and 889 differentially expressed genes in a module representing preeclampsia were identified. Functional analysis of molecular signatures associated with IUGR identified P13K/AKT, mTOR, p70S6K, apoptosis and IGF-1 signaling as being affected. Analysis of variance of GSEA-predicted microRNAs indicated that miR-194 was significantly down-regulated both in preeclampsia (p = 0.0001) and IUGR (p = 0.0304), and miR-149 was significantly down-regulated in preeclampsia (p = 0.0168).

DISCUSSION

Implementation of MMC, allowed identification of genes disregulated in IUGR and preeclampsia. The reliability of MMC was validated by comparing to previous linear modeling analysis of preeclamptic placentas.

CONCLUSION

MMC allowed the elucidation of a molecular signature associated with preeclampsia and a subset of IUGR samples. This allowed the identification of genes, pathways, and microRNAs affected in these diseases.

A lesson for cancer research: placental microarray gene analysis in preeclampsia

Tumor progression and pregnancy share many common features, such as immune tolerance and invasion. The invasion of trophoblasts in the placenta into the uterine wall is essential for fetal development, and is thus precisely regulated. Its deregulation has been implicated in preeclampsia, a leading cause for maternal and perinatal mortality and morbidity. Pathogenesis of preeclampsia remains to be defined. Microarray-based gene profiling has been widely used for identifying genes responsible for preeclampsia. In this review, we have summarized the recent data from the microarray studies with preeclamptic placentas. Despite the complex of gene signatures, suggestive of the heterogeneity of preeclampsia, these studies identified a number of differentially expressed genes associated with preeclampsia. Interestingly, most of them have been reported to be tightly involved in tumor progression. We have discussed these interesting genes and analyzed their potential molecular functions in preeclampsia, compared with their roles in malignancy development. Further investigations are warranted to explore the involvement in molecular network of each identified gene, which may provide not only novel strategies for prevention and therapy for preeclampsia but also a better understanding of cancer cells. The trophoblastic cells, with their capacity for proliferation and differentiation, apoptosis and survival, migration, angiogenesis and immune modulation by exploiting similar molecular pathways, make them a compelling model for cancer research.

The obstetric syndromes: clinical relevance of placental hormones

Preterm delivery, preeclampsia and intrauterine growth restriction are the major diseases of pregnancy. A key role in their pathogenesis is played by the placenta, which is the source of hormones and other important regulatory molecules providing the metabolic and endocrine homeostasis of the fetal-placental unit. Since obstetric syndromes are characterized by important maternal and neonatal morbidity and mortality worldwide, numerous efforts have been made over the years to prevent and treat them. Due to their complex pathogenesis, however, the therapy is poor and not very effective. Therefore, great emphasis is currently given to the prevention of these diseases through the identification of biochemical and biophysical markers, among which placental factors play a crucial role. The increasing knowledge of the role of placental molecules can indeed lead to the development of new therapeutic and diagnostic tools.

Congenital anomalies after assisted reproductive technology

Worldwide, more than 5 million children have been born after assisted reproductive technology (ART), and in many developed countries ART infants represent more than 1% of the birth cohorts. It is well known that ART children are at increased risk of congenital malformations even after adjustment for known confounders such as maternal age. The proportion of ART children is not negligible, and knowledge about the causes of the higher risk of congenital malformations is crucial to develop prevention strategies to reduce the future risk in ART children. The aim of this review is to summarize the literature on the association between ART and congenital anomalies with respect to subfertility, fertility treatment other than ART, and different ART methods including intracytoplasmic sperm injection, blastocyst culture, and cryotechniques. Trends over time in ART and congenital anomalies will also be discussed.

Cell-free DNA as a potential marker to predict carbon tetrachloride-induced acute liver injury in rats

PURPOSE

Finding an optimal biomarker for the noninvasive evaluation of acute liver injury (ALI) may be of great value in predicting clinical outcomes and investigating potential treatments. We investigated cell-free DNA (CFD) as a potential biomarker to predict carbon tetrachloride-induced ALI in rats.

METHODS

Forty-five Sprague-Dawley rats were randomly assigned to three groups. ALI was induced by carbon tetrachloride via a nasogastric tube at 1, 2.5, or 5 ml/kg of a 50 % solution. Fifteen additional rats underwent a sham procedure. Blood samples were drawn at time t which was 0 (baseline), 3, 6, 12, 24, 48, 72, 96, and 120 h for the measurements of CFD, glutamate-pyruvate transaminase (GPT), glutamate-oxaloacetate transaminase (GOT), and total bilirubin. Prothrombin time and histology were examined at 24 and 120 h following injection of 5 ml/kg carbon tetrachloride in 18 additional rats and in 10 control rats.

RESULTS

CFD levels in rats subjected to carbon tetrachloride-induced ALI were significantly increased in all blood samples starting at 12 h after the induction of ALI (p < 0.001), reaching peak levels at 24 h. Blood GOT, GPT, and total bilirubin were elevated in all blood samples starting at 3 h after the induction of ALI (p < 0.0001), reaching peak levels by 48 h. A positive correlation was demonstrated between CFD levels and GOT (R (2) = 0.92), GPT (R (2) = 0.92), and total bilirubin (R (2) = 0.76). CFD levels correlated with liver damage seen on histological examination, as well as predicted liver damage, at 24 h after ALI.

CONCLUSIONS

CFD may be a useful biomarker for the prediction and measurement of ALI. There is no evidence to suggest that CFD is superior to other available noninvasive biomarkers.

Promoter hypomethylation of TIMP3 is associated with pre-eclampsia in a Chinese population

A study by Yuen RK, Penaherrera MS, von Dadelszen P, McFadden DE, Robinson WP. DNA methylation profiling of human placentas reveals promoter hypomethylation of multiple genes in early-onset preeclampsia. Eur J Hum Genet 2010;18:1006-1012 based on a Canadian population found the tissue inhibitor of the metalloproteinase 3 (TIMP3) gene to be hypomethylated in pre-eclampsia (PE) placentas and to be a potential prenatal marker for early onset PE. To further explore the role of TIMP3 in PE and to investigate whether the TIMP3 promoter shows the same methylation pattern in the Han Chinese population, we analyzed a complete methylation assay of TIMP3 including the promoter region studied in the Canadian report and the neighboring CpG island in placentas (cases n = 41, controls n = 22) maternal peripheral blood (cases n = 3; controls n = 6) and umbilical cord blood (cases n = 7; controls n = 8) using MassArray EpiTyper (Sequenom, San Diego, CA, USA). Our results confirmed the finding of aberrant TIMP3 promoter methylation in PE placentas (mean = 0.405) compared with those in controls (mean = 0.534, P = 9.40 × 10(-7)). A tissue-specific methylation pattern between placentas (mean = 0.459) and bloods (mean = 0.961, P = 6.91 × 10(-13)) was also demonstrated in our clinical samples. Furthermore, a nearly 2-fold increase in TIMP3 expression for the hypomethylated promoter was found in PE placentas (P = 0.007), pointing to a negative relationship between TIMP3 methylation and the expression (R = -0.758, P = 0.029). In conclusion, we replicated the findings of Yuen et al. in our Han Chinese-based study, confirming that TIMP3 is likely to be involved in the etiology of PE and that hypomethylated and placenta-specific TIMP3 may be a potential marker for early diagnosis of PE in maternal plasma.

Can detection of late-onset PE at triage by sflt-1 or PlGF be improved by the use of additional biomarkers?

OBJECTIVE

Accurate identification of preeclampsia (PE) at triage is essential to reduce maternal and fetal morbidity and mortality. The use of maternal blood based biomarkers may facilitate the clinician's ability to assess high risk pregnancies at triage.

METHODS

A prospective cross-sectional study was performed to investigate the value of soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng), placental growth factor (PlGF), sP-selectin, cell-free fetal DNA and total cell-free DNA in patients with late-onset PE versus gestational age-matched controls.

RESULTS

The diagnosis of late-onset PE (n = 21) at triage was significantly improved by altered levels of sFlt-1, sEng, PlGF and cffDNA as compared with controls (n = 42). Areas under the receiver operating characteristic curves [AUC, Standard error (SE)] for predicting PE were for marker measurements prior to the first stage of labor as follows: sFlt-1 0.97 (SE 0.02), sEng 0.91 (SE 0.04), PlGF 0.95 (SE 0.04), cell-free fetal DNA (DYS 14) 0.84 (SE 0.06), total cell-free DNA (glyceraldehyde 3-phosphate dehydrogenase) 0.61 (SE 0.07), sP-selectin 0.51 (SE 0.07). The discrimination could be slightly improved by using the slt1-PlGF ratio: 0.98 (SE 0.02).

CONCLUSION

The sFlt-1 is a useful tool for the detection of late-onset PE at triage. This can be slightly improved using a sFlt-1/PIGF ratio. The addition of other biomarkers did not improve screening performance for late-onset PE.

Quantitative polymerase chain reaction-based analysis of podocyturia is a feasible diagnostic tool in preeclampsia

Preeclampsia is a significant cause of maternal and fetal morbidity and mortality worldwide. A clinically useful screening test that can predict development of preeclampsia at an early stage is urgently needed. The detection of podocyturia by immunohistochemistry after cell culture has been noted as a reliable marker for preeclampsia. However, this method is laborious and carries the risk of cell culture contamination. The aim of this study was to investigate the diagnostic value of quantitative polymerase chain reaction as a rapid method to detect preeclampsia. Clean-catch urine samples were collected from preeclamptic (n=35), healthy pregnant (n=34), and healthy nonpregnant (n=12) women. Furthermore, a control group of women with gestational hypertension (n=5) was included. Quantitative polymerase chain reaction analysis was performed for podocyte-specific markers. Receiver operating characteristic curve analyses were performed. Significantly elevated mRNA levels of nephrin, podocin, and vascular endothelial growth factor were detected in preeclamptic women compared with healthy pregnant and healthy nonpregnant controls. In addition, significantly elevated levels of nephrin mRNA were detected in urine of preeclamptic women compared with women with gestational hypertension. A positive correlation (ρ=0.82; P<0.0001) was observed between nephrin and vascular endothelial growth factor mRNA levels in preeclamptic women. Receiver operating characteristic curve analyses demonstrated a strong ability of this method to discriminate between the different study groups. Quantitative polymerase chain reaction analysis of podocyte-specific molecules in urine samples is a rapid and reliable method to quantify podocyturia. We demonstrate that this method distinguishes preeclamptic patients from healthy controls and women with gestational hypertension. This method may be a tool for the detection of preeclampsia at an earlier stage, thereby preventing maternal and fetal morbidity and mortality.

Preeclampsia and retinopathy of prematurity in preterm births

OBJECTIVE

The relationship between gestational hypertension, preeclampsia, and the risk of retinopathy of prematurity (ROP) remains unclear. Thus, we used a large cohort database to study the influence of maternal gestational hypertension and preeclampsia on the occurrence of ROP in preterm infants.

METHODS

We used data from a previous retrospective cohort study that includes 25,473 eligible preterm neonates. We examined the association between gestational hypertension, preeclampsia, and ROP while controlling for potential confounders by multiple logistic regression analysis.

RESULTS

Of the 8758 early preterm infants (gestational age <34 weeks), 1024 (11.69%) had ROP, while of the 16,715 late preterm infants, only 29 (0.17%) had ROP. After adjusting for confounders, preeclampsia was associated with a significantly reduced risk of ROP (adjusted odds ratio [aOR], 0.65; 95% confidence interval [CI], 0.49-0.86 for early preterm birth; aOR, 0.10; 95% CI, 0.01-0.93 for late preterm birth; aOR, 0.66; 95% CI, 0.50-0.87 for all preterm births). Gestational hypertension was not significantly associated with ROP at early or late preterm births.

CONCLUSIONS

Preeclampsia, but not gestational hypertension, was associated with a reduced risk of ROP in preterm births.

PP13 and PAPP-A in the First and Second Trimesters: Predictive Factors for Preeclampsia?

Background. Preeclampsia affects 5-6% of all pregnancies. Predictive factors of preeclampsia can be helpful in early diagnosis of this disease. In this study the predictive values of biochemical markers placenta protein 13 (PP13) and pregnancy-associated plasma protein A (PAPP-A) have been assessed in early diagnosis of preeclampsia. Methods. This case-control study was conducted on 1500 women who presented to a healthcare center of Sari, Iran, between 2010 and 2011. Blood samples were drawn in weeks 11–13 and 24–28 of pregnancy. Of them who developed preeclampsia were considered as case group. A control group consisted of similar women regarding mean age, body mass index (BMI), and pregnancy age. PAPP-A and PP13 serum levels were measured. Data were analyzed using proper statistical tests. Results. PAPP-A and PP13 serum levels were significantly lower in both the first and second trimesters in women who developed preeclampsia (P < 0.001). The cumulative value of all four variables with cut-off point of 238.5 has sensitivity, specificity of 91.0%, and undercurve surface of 0.968 which is the most diagnostic value for preeclampsia. Conclusion. It is possible to advantage measuring of PAPP-A and PP13 in the first and second trimesters especially their cumulative values in both trimesters for prediction of the incidence of preeclampsia.

A comprehensive review of hypertension in pregnancy

Hypertension is the most common medical disorder encountered during pregnancy. Hypertensive disorders are one of the major causes of pregnancy-related maternal deaths in the United States. We will present a comprehensive update of the literature pertinent to hypertension in pregnancy. The paper begins by defining and classifying hypertensive disorders in pregnancy. The normal vascular and renal physiological changes which occur during pregnancy are detailed. We will summarize the intriguing aspects of pathophysiology of preeclampsia, emphasizing on recent advances in this field. The existing diagnostic tools and the tests which have been proposed for screening preeclampsia are comprehensively described. We also highlight the short- and long-term implications of preeclampsia. Finally, we review the current management guidelines, goals of treatment and describe the potential risks and benefits associated with various antihypertensive drug classes. Preeclampsia still remains an enigma, and the present management focuses on monitoring and treatment of its manifestations. We are hopeful that this in depth critique will stimulate the blossoming research in the field and assist practitioners to identify women at risk and more effectively treat affected individuals.

Differential placental expression profile of human Growth Hormone/Chorionic Somatomammotropin genes in pregnancies with pre-eclampsia and gestational diabetes mellitus

The human GH/CSH cluster consisting of one pituitary-expressed (GH1) and four placenta-expressed loci has been implicated in maternal metabolic adaptation to pregnancy, regulation of intrauterine and postnatal growth. We investigated how the mRNA expression profile of placental GH2, CSH1 and CSH2 genes and their alternative transcripts correlates with maternal pre-eclampsia (PE) and/or gestational diabetes mellitus (GD). The expression of studied genes in PE placentas (n=17) compared to controls (n=17) exhibited a trend for reduced transcript levels. The alternative transcripts retaining intron 4, GH2-2 and CSH1-2 showed significantly reduced expression in PE cases without growth restriction (P=0.007, P=0.008, respectively). In maternal GD (n=23), a tendency of differential expression was detected only for the GH2 gene and in pregnancies with large-for-gestational-age newborns. Our results, together with those reported by others, are consistent with a pleiotropic effect of placental hGH/CSH genes at the maternal-fetal interface relating to the regulation of fetal growth and the risk of affected maternal metabolism.

Microarray screening for novel preeclampsia biomarker candidates

INTRODUCTION

Our aim was to identify novel biomarker candidates for the near-term prediction of preeclampsia in a homogenous collective. In this study, we screened at the genome-wide level for gene expression in placental villous tissue from patients with severe preeclampsia in comparison to normal healthy pregnancies.

MATERIAL AND METHODS

Total RNA was extracted from placental villous tissue from 9 preeclamptic patients and 7 normotensive controls after scheduled cesarean sections. After sample pooling, gene expression analysis was performed using six Affymetrix Human Gene 1.0 ST arrays, followed by quantitative RT-PCR and validation of selected markers in the serum of patients at the protein level.

RESULTS

In total, 896 significantly differentially expressed genes were identified (p ≤ 0.05). After restricting these to molecules present in the circulation, 9 upregulated and 5 downregulated genes were selected. Four of them (β-hCG, HTRA4, LHB1, all upregulated; and NOX4, downregulated) were validated by quantitative real-time RT-PCR. Finally, the maternal plasma protein levels of 2 of these genes (LHB and β-hCG) were confirmed to be significantly different between preeclampsia cases and controls.

DISCUSSION

We identified 14 potential new biomarker candidates for preeclampsia and validated 4 of them by quantitative RT-PCR and 2 of them with subsequent serum protein analyses. Further studies will assess the optimal marker combination for the imminent prediction of impending preeclampsia.

Vessel remodelling, pregnancy hormones and extravillous trophoblast function

During early human pregnancy, extravillous trophoblast (EVT) cells from the placenta invade the uterine decidual spiral arterioles and mediate the remodelling of these vessels such that a low pressure, high blood flow can be supplied to the placenta. This is essential to facilitate normal growth and development of the foetus. Defects in remodelling can manifest as the serious pregnancy complication pre-eclampsia. During the period of vessel remodelling three key pregnancy-associated hormones, human chorionic gonadotrophin (hCG), progesterone (P(4)) and oestradiol (E(2)), are found in high concentrations at the maternal-foetal interface. Potentially these hormones may control EVT movement and thus act as regulators of vessel remodelling. This review will discuss what is known about how these hormones affect EVT proliferation, migration and invasion during vascular remodelling and the potential relationship between hCG, P(4), E(2) and the development of pre-eclampsia.

Genesis of preeclampsia: an epidemiological approach

THERE ARE ANALYZED SOME OF THE MAIN ASPECTS RELATED TO THE CAUSALITY OF PREECLAMPSIA, PRIVILEGING TWO TYPES OF MODELS: the clinic model and the epidemiologic model, first one represented by the hypothesis of the reduced placental perfusion and the second one considering the epidemiologic findings related to the high levels of psychosocial stress and its association with preeclampsia. It is reasoned out the relevance of raising the causality of the disease from an interdisciplinary perspective, integrating the valuable information generated from both types, clinical and epidemiologic, and finally a tentative explanatory model of preeclampsia is proposed, the subclinical and sociocultural aspects that predispose and trigger the disease are emphasized making aspects to stand out: the importance of reduced placental perfusion as an indicator of individual risk, and the high levels of physiological stress, as a result of the unfavorable conditions of the psychosocial surroundings (indicator of population risk) of the pregnant women.

Plasma kisspeptin levels in pregnancies with diabetes and hypertensive disease as a potential marker of placental dysfunction and adverse perinatal outcome

BACKGROUND

The aim of this study was to prospectively evaluate plasma kisspeptin levels in 129 singleton pregnancies with diabetes [pregestational insulin-dependent diabetes mellitus (type 1) and gestational diabetes (GD)] and hypertensive disease [chronic hypertension (CH), gestational hypertension, and preeclampsia (PE)] as a potential marker of placental dysfunction and adverse perinatal outcome.

STUDY DESIGN

Kisspeptin levels were evaluated in the first, second, and third trimesters in patients with type 1 diabetes (16 patients), H (22), and healthy control (25) and in the second and third trimesters in patients with GD (20), gestational hypertension (18), and PE (28). Maternal kisspeptin levels were correlated with pregnancy outcome, parameters of fetoplacental circulation, ultrasound-detected abnormalities of placental morphology, and placental weight at delivery.

RESULTS

In pregnancies with type 1 diabetes and H, mean kisspeptin levels were significantly lower compared with the control group (p<0.001 in the first and second trimesters and p<0.05 in the third trimester). Decreased plasma kisspeptin levels in the second and third trimesters were found in patients with GD (p<0.001 in the second and third trimesters) and PE (p<0.001 in the second trimester and p<0.05 in the third trimester). In patients with PE and placental dysfunction, low kisspeptin levels in the third trimester were associated with adverse perinatal outcome.

CONCLUSIONS

Our study demonstrates reduced kisspeptin levels in pregnancies with diabetes, H, PE, and placental dysfunction. In patients with PE and placental dysfunction, decreased kisspeptin levels were associated with adverse perinatal outcome. Larger studies are needed to investigate the role of kisspeptin as a potential marker of placental dysfunction and adverse perinatal outcome.

Age at menarche, menstrual characteristics, and risk of preeclampsia

We examined associations of age at menarche and menstrual characteristics with the risk of preeclampsia among participants (n = 3,365) of a pregnancy cohort study. Data were collected using in-person interviews and medical record abstraction. Logistic regression was used to estimate adjusted odds ratio (OR) and 95% confidence interval (95% CI). There was a significant inverse association between age at menarche and risk of preeclampsia (P value for trend < 0.05). Association of long cycle length (>36 days) with higher risk of preeclampsia was present only among women who had prepregnancy body mass index <25 kg/m(2) (interaction P value = 0.04). Early menarche is associated with higher risk of preeclampsia. Prepregnancy weight may modify associations of long menstrual cycles with risk of preeclampsia.

Serum S100B in pregnancy complicated by preeclampsia: A case-control study

BACKGROUND

Serum S100B is a protein produced and released primarily by astrocytes of the Central Nervous System (CNS). Elevated levels of serum S100B are associated with several types of pathological conditions of the brain, including the eclampsia in pregnant women. The aim of this study was to compare serum S100B concentrations in pregnant women with severe and mild preeclampsia (PE) with S100B serum levels in normotensive pregnant women.

MATERIAL AND METHODS

Serum S100B protein was measured in normotensive pregnant women (n=15) and in women with mild PE (n=12) or severe PE (n=34). The serum S100B level (μg/L) was determined by an luminometric assay.

RESULTS

Sixty-one expectant mothers were studied, aged 26.6±8.7 (mean±SD) years and with a gestational age of 33.3±4.2 weeks. The severe PE group demonstrated higher S100B levels (0.20±0.19), as compared with mild PE (0.07±0.05) or normotensive groups (0.04±0.05).

CONCLUSION

Elevated serum S100B levels in pregnant women with severe PE suggest that some kind of neural damage and subsequent astrocytic release of S100B is not dependent on the progression from severe preeclampsia to eclampsia.

Insulin stimulation of Akt/PKB phosphorylation in the placenta of preeclampsia patients

CONTEXT AND OBJECTIVE

Preeclampsia is a multi-systemic disease and one of the most frequent severe health problems during pregnancy. Binding of insulin triggers phosphorylation and activates cytoplasmic substrates such as phosphatidylinositol 3 kinase (PI3K). Phosphorylation of membrane phosphoinositide 2 (PIP2) to phosphoinositide 3 (PIP3) by PI3K starts Akt/PKB activation. Defects in phosphorylation of the insulin receptor and its substrates have an important role in insulin resistance. Studies have shown that insulin resistance is associated with preeclampsia and its pathophysiology. The aim here was to investigate insulin stimulation of the Akt/PKB pathway in the placenta, in normal and preeclampsia parturients.

DESIGN AND SETTING

Cross-sectional study in a tertiary public university hospital.

METHODS

Placentas were collected from 12 normal and 12 preeclampsia patients. These were stimulated and analyzed using Western blot to quantify the Akt/PKB phosphorylation.

RESULTS

The insulin stimulation was confirmed through comparing the stimulated group (1.14 ± 0.10) with the non-stimulated group (0.91 ± 0.08; P < 0.001). The phosphorylation of Akt/PKB did not differ between the placenta of the normal patients (1.26 ± 0.16) and those of the preeclampsia patients (1.01 ± 0.11; P = 0.237).

CONCLUSIONS

In vitro insulin stimulation of the human placenta has been well established. There was no difference in Akt/PKB phosphorylation, after stimulation with insulin, between placentas of normal and preeclampsia patients. Nevertheless, it cannot be ruled out that the Akt/PKB signaling pathway may have a role in the pathophysiology of preeclampsia, since the substrates of Akt/PKB still need to be investigated.

Translational analysis of mouse and human placental protein and mRNA reveals distinct molecular pathologies in human preeclampsia

Preeclampsia (PE) adversely impacts ~5% of pregnancies. Despite extensive research, no consistent biomarkers or cures have emerged, suggesting that different molecular mechanisms may cause clinically similar disease. To address this, we undertook a proteomics study with three main goals: (1) to identify a panel of cell surface markers that distinguish the trophoblast and endothelial cells of the placenta in the mouse; (2) to translate this marker set to human via the Human Protein Atlas database; and (3) to utilize the validated human trophoblast markers to identify subgroups of human preeclampsia. To achieve these goals, plasma membrane proteins at the blood tissue interfaces were extracted from placentas using intravascular silica-bead perfusion, and then identified using shotgun proteomics. We identified 1181 plasma membrane proteins, of which 171 were enriched at the maternal blood-trophoblast interface and 192 at the fetal endothelial interface with a 70% conservation of expression in humans. Three distinct molecular subgroups of human preeclampsia were identified in existing human microarray data by using expression patterns of trophoblast-enriched proteins. Analysis of all misexpressed genes revealed divergent dysfunctions including angiogenesis (subgroup 1), MAPK signaling (subgroup 2), and hormone biosynthesis and metabolism (subgroup 3). Subgroup 2 lacked expected changes in known preeclampsia markers (sFLT1, sENG) and uniquely overexpressed GNA12. In an independent set of 40 banked placental specimens, GNA12 was overexpressed during preeclampsia when co-incident with chronic hypertension. In the current study we used a novel translational analysis to integrate mouse and human trophoblast protein expression with human microarray data. This strategy identified distinct molecular pathologies in human preeclampsia. We conclude that clinically similar preeclampsia patients exhibit divergent placental gene expression profiles thus implicating divergent molecular mechanisms in the origins of this disease.

Establishing a biologic specimens repository for reproductive clinical trials: technical aspects

The individual research group or independent investigator often requires access to samples from a unique well characterized subject population. Cohorts of such samples from a well-defined comparative population are rare and limited access can impede progress. This bottleneck can be removed by accessing the samples provided by biorepositories such as the NIH/NICHD Cooperative Reproductive Medicine Network (RMN) Biorepository (detailed in the preceeding manuscript in this issue. In those cases where the individual research group or independent investigator already has access to a unique population, comparisons between well-defined groups are often sought to contextualize the data. In both cases seamless integration of data resources associated with the samples is required to ensure optimal comparisons. At the most basic level this requires standardization of sample collection and storage, as well as a de-identified data base containing demographic, clinical, and laboratory values. To facilitate such interoperability, the reagents and protocols that have been adopted by the RMN Biorepository for the collection and storage of serum, blood, saliva and sperm are described.

Association of angiotensin-converting enzyme intron 16 insertion/deletion and angiotensin II type 1 receptor A1166C gene polymorphisms with preeclampsia in South East of Iran

Some evidence suggests that a variety of genetic factors contributed in pathogenesis of the preeclampsia. The aim of this study was to assess the association between the angiotensin-converting enzyme (ACE) I/D and angiotensin II type1 receptor A1166C polymorphisms with preeclampsia. This study was performed in 125 preeclamptic pregnant women and 132 controls. The I/D Polymorphism of the ACE gene was assessed by polymerase chain reaction and the A1166C Polymorphism of the AT1R gene was determined by restriction fragment length polymorphism. The genotype and allele frequencies of I/D polymorphism differed between two groups. The risk of preeclampsia was 3.2-fold in pregnant women with D allele (OR, 3.2 [95% CI, 1.1 to 3.8]; P = 0.01). The distribution of the AT1R gene A1166C polymorphism was similar in affected and control groups. Our results supported that presence of the I/D polymorphism of ACE gene is a marker for the increased risk of preeclampsia.

Characterization of discriminatory urinary proteomic biomarkers for severe preeclampsia using SELDI-TOF mass spectrometry

OBJECTIVE

To analyze the proteomic pattern in urine for distinguishing severe preeclampsia from mild preeclampsia and normotensive controls using surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF-MS).

STUDY DESIGN

Urine samples were collected from women with severe preeclampsia (n=11 [sPE]), mild preeclampsia (n=7 [mPE]), and normotensive controls (n=8) and analyzed by SELDI-TOF-MS to identify discriminatory protein peaks in the sPE cohort. A scoring system was constructed--designated as Preeclampsia Proteomic Score of Urine (PPSU)--to differentiate sPE from mPE and normotensive controls.

RESULTS

Four discriminatory protein peaks were identified (m/z ratio: 4155, 6044, 6663, and 7971), all of which were down-regulated in women with sPE. PPSU scores in women with sPE were significantly lower than that in both mPE and controls (sPE 0 [0-4] vs. mPE 3 [0-4] vs. controls 4 [2-4]; median [range]; P<0.05). PPSU<2 had a sensitivity of 90.9% and specificity of 93.3% in discriminating patients with sPE from mPE and controls.

CONCLUSION

Proteomic analysis of urine can accurately distinguish sPE from mPE and normotensive controls.

Angiogenic factors and preeclampsia

Preeclampsia, a hypertensive disorder peculiar to pregnancy, is a systemic syndrome that appears to originate in the placenta and is characterized by widespread maternal endothelial dysfunction. Until recently, the molecular pathogenesis of phenotypic preeclampsia was largely unknown, but recent observations support the hypothesis that altered expression of placental anti-angiogenic factors are responsible for the clinical manifestations of the disease. Soluble Flt1 and soluble endoglin, secreted by the placenta, are increased in the maternal circulation weeks before the onset of preeclampsia. These anti-angiogenic factors produce systemic endothelial dysfunction, resulting in hypertension, proteinuria, and the other systemic manifestations of preeclampsia. The molecular basis for placental dysregulation of these pathogenic factors remains unknown, and as of 2011 the role of angiogenic proteins in early placental vascular development was starting to be explored. The data linking angiogenic factors to preeclampsia have exciting clinical implications, and likely will transform the detection and treatment of preeclampsia.

Levels of soluble fms-like tyrosine kinase one in first trimester and outcomes of pregnancy: a systematic review

Angiogenic factors are involved in formation of new blood vessels required for placental development and function; and critical for fetal growth and development. Soluble fms-like tyrosine kinase 1(sFlt-1) is an anti-angiogenic protein that inhibits formation of new blood vessels resulting in potential pregnancy complications. The objective of this study was to undertake a systematic review to assess levels of sFlt-1 in early pregnancy and association with adverse pregnancy outcomes. PubMed and Medline databases and reference lists were searched up to July 2010. Inclusion criteria were pregnant women, blood sample taken during first trimester and assessment/reporting of sFlt-1 concentrations and subsequent pregnancy complications. Twelve relevant studies were identified of 71 to 668 women. No pooling of results was undertaken due to variation in sFlt-1 concentrations (range, 166-6,349 pg/ml amongst controls), samples used (serum, plasma), different summary statistics (mean, median, odds ratio) and outcome definitions applied. Levels of sFlt-1 were generally higher among women who developed preeclampsia (11 studies) or gestational hypertension (two studies), but not significantly different to normotensive women in most studies. There was no consistent pattern in association between sFlt-1 concentrations and fetal growth restriction (4 studies); and levels were non-significantly higher for women with postpartum bleeding (1 study) and significantly lower for stillbirths (1 study).This review found no clear evidence of an association between sFlt-1 levels in first trimester and adverse pregnancy outcomes. However, findings were affected by methodological, biological and testing variations between studies; highlighting the need for consistent testing of new biomarkers and reporting of outcome measures.

Fetal hemoglobin and α1-microglobulin as first- and early second-trimester predictive biomarkers for preeclampsia

OBJECTIVE

The aim of this study was to evaluate fetal hemoglobin (HbF) and α(1)-microglobulin (A1M) in maternal serum as first-trimester biomarkers for preeclampsia (PE).

STUDY DESIGN

The design was a case-control study. We included 96 patients in the first trimester of pregnancy (60 with PE and 36 controls). Venous serum samples were analyzed for HbF and total hemoglobin (Hb) by enzyme-linked immunosorbent assay and for A1M by radioimmunoassay. Sensitivity and specificity was calculated by logistic regression and receiver operating characteristic curve analysis.

RESULTS

The HbF/Hb ratio and A1M concentration were significantly elevated in serum from women with subsequent development of PE (P < .0001). The optimal sensitivity and specificity was obtained using the biomarkers in combination; 69% sensitivity for a 5% screen positive rate and 90% sensitivity for a 23% screen positive rate.

CONCLUSION

The study suggests that HbF/Hb ratio in combination with A1M is predictive biomarkers for PE.