A Critical Review of Early-Onset and Late-Onset Preeclampsia

Mitochondrial role in adaptive response to stress conditions in preeclampsia

Preeclampsia (PE) is a pregnancy-specific syndrome, characterized in general by hypertension with proteinuria or other systemic disturbances. PE is the major cause of maternal and fetal morbidity and mortality worldwide. However, the etiology of PE still remains unclear. Our study involved 38 patients: 14 with uncomplicated pregnancy; 13 with early-onset PE (eoPE); and 11 with late-onset PE (loPE). We characterized the immunophenotype of cells isolated from the placenta and all biopsy samples were stained positive for Cytokeratin 7, SOX2, Nestin, Vimentin, and CD44. We obtained a significant increase in OPA1 mRNA and protein expression in the eoPE placentas. Moreover, TFAM expression was down-regulated in comparison to the control (p < 0.01). Mitochondrial DNA copy number in eoPE placentas was significantly higher than in samples from normal pregnancies. We observed an increase of maximum coupled state 3 respiration rate in mitochondria isolated from the placenta in the presence of complex I substrates in the eoPE group and an increase of P/O ratio, citrate synthase activity and decrease of Ca(2+)-induced depolarization rate in both PE groups. Our results suggest an essential role of mitochondrial activity changes in an adaptive response to the development of PE.

Metabolomic determination of pathogenesis of late-onset preeclampsia

OBJECTIVE

Our primary objective was to apply metabolomic pathway analysis of first trimester maternal serum to provide an insight into the pathogenesis of late-onset preeclampsia (late-PE) and thereby identify plausible therapeutic targets for PE.

METHODS

NMR-based metabolomics analysis was performed on 29 cases of late-PE and 55 unaffected controls. In order to achieve sufficient statistical power to perform the pathway analysis, these cases were combined with a group of previously analyzed specimens, 30 late-PE cases and 60 unaffected controls. Specimens from both groups of cases and controls were collected in the same clinical centers during the same time period. In addition, NMR analyses were performed in the same lab and using the same techniques.

RESULTS

We identified abnormalities in branch chain amino acids (valine, leucine and isoleucine) and propanoate, glycolysis, gluconeogenesis and ketone body metabolic pathways. The results suggest insulin resistance and metabolic syndrome, mitochondrial dysfunction and disturbance of energy metabolism, oxidative stress and lipid dysfunction in the pathogenesis of late PE and suggest a potential role for agents that reduce insulin resistance in PE.

CONCLUSIONS

Branched chain amino acids are known markers of insulin resistance and strongly predict future diabetes development. The analysis provides independent evidence linking insulin resistance and late-PE and suggests a potentially important therapeutic role for pharmacologic agents that reduce insulin resistance for late-PE.

The Role of Adenomyosis in the Pathogenesis of Preeclampsia

INTRODUCTION

Adenomyosis can cause defective deep placentation. Preeclampsia is known to be associated with abnormal placentation. The aim of this study was to compare the presence of adenomyosis on magnetic resonance imaging in patients with and without history of preeclampsia in order to investigate the possible role of adenomyosis in the pathogenesis of preeclampsia.

MATERIALS AND METHODS

This prospective, randomized study consisted of patients with (n = 35) and without (n = 34) history of preeclampsia. Direct (submucosal microcysts, adenomyoma and cystic adenomyoma) and indirect (maximal thickness of junctional zone, ratio of maximal thickness of junctional zone to myometrial thickness, junctional zone differential, focal thickening of junctional zone, globally enlarged uterus and non-uniform junctional zone contours) signs of adenomyosis were assessed by pelvic magnetic resonance imaging.

RESULTS

The prevalence of adenomyosis was found to be more common in patients with preeclampsia und fetal growth restriction compared to patients without fetal growth restriction (94.4 vs. 64.7 %; p = 0.041), respectively. There was a strong association between maximal thickness of junctional zone (9 vs. 13 mm, p = 0.005), ratio of maximal thickness of junctional zone to myometrial thickness (0.42 vs. 0.66, p = 0.001) and junctional zone differential (3 vs. 5 mm, p = 0.02) and late-onset preeclampsia.

CONCLUSIONS

Presence of adenomyoma is more common in patients with preeclampsia complicated with fetal growth restriction. Indirect signs of adenomyosis detected on pelvic magnetic resonance imaging might have a role in the pathogenesis of late-onset preeclampsia.

Placental exosomes and pre-eclampsia: Maternal circulating levels in normal pregnancies and, early and late onset pre-eclamptic pregnancies

INTRODUCTION AND AIM

Exosomes are a subtype of extracellular vesicle (20-130 nm) released by biological cells under normal and pathological conditions. Although there have been reports of circulating exosomes in normal pregnancy, the relevance of placental-derived exosomes in normal and abnormal pregnancies still needs to be elucidated. The aim of this study was to quantify total and placental-derived exosomes in maternal plasma from normal (N), early onset- and late onset-preeclampsia (PE).

METHOD

Plasma samples were obtained from pregnant women in the third trimester, for the isolation of exosomes by differential ultracentrifugation. Total exosomes were quantified using nanoparticle tracking analysis and immuno-reactive exosomal CD63 quantification. Placental-derived exosomes were quantified using placental alkaline phosphatase (PLAP) as a specific marker. The contribution of placental-derived exosomes to total exosomes in maternal plasma was determined by the ratio of PLAP⁺ exosomes to CD63⁺ exosomes.

RESULTS

The concentration of total exosomes significantly increased in early onset-PE and late onset-PE compared to N (≤33 weeks) and N (≥34 weeks). The relative concentration of placental-derived exosomes significantly increased in early onset-PE but decreased in late onset-PE compared to N. The ratio of PLAP⁺ exosomes to total number of exosomes significantly decreased in early onset-PE and late onset-PE. A positive correlation between total and placental-derived exosomes were obtained in N (≤33 weeks: Pearson's r = 0.60, ≥34 weeks: Pearson's r = 0.67) and early onset-PE (Pearson's r = 0.51, p < 0.05) with the inverse in late onset-PE (Pearson's r = -0.62, p < 0.01).

CONCLUSION

The differences in the contribution of placental-derived exosomes to total exosomes in maternal circulation suggests a possible pathophysiological role of placental-derived exosomes in pre-eclampsia.

Expression of the complement system's activation factors in plasma of patients with early/late-onset severe pre-eclampsia

PROBLEM

To investigate the expression of complement activation factors in plasma of patients with early/late-onset severe pre-eclampsia.

METHODS

A case-control study was performed. The study group consisted of 30 cases of early-onset severe pre-eclampsia (EOSPE) and 30 cases of late-onset severe pre-eclampsia (LOSPE). Thirty cases were selected as the early-onset control group (E-control) and 30 as the late-onset control group (L-control). ELISA was used to test C1q, C4d, MBL, Bb, C3a, C5a, and MAC in the maternal peripheral circulation.

RESULTS

The complement activation factors Bb, C3a, C5a, and MAC were increased significantly in EOSPE (all P<.01) and LOSPE (P value: .027, <.001, .001, and <.001, respectively) compared with E/L-control. C1q and C4d were increased significantly in LOSPE (P value: .003 and .014, respectively) compared with L-control.

CONCLUSION

Abnormal activation of the complement system exists in the maternal circulation of patients with early- and late-onset severe pre-eclampsia. In patients complicated with LOSPE, the complement system was activated through both the classical and alternative pathways, while in EOSPE, the complement system was activated mainly through the alternative pathway.

Hypertensive disorders of pregnancy

PURPOSE

In this continuing professional development module, we review recent Society of Obstetricians and Gynaecologists of Canada (SOGC) guidelines for the classification and diagnosis of hypertensive disorders of pregnancy (HDP) as well as review the clinical features, laboratory investigations, and outcomes of HDP. We explore the evidence for anesthetic management and prevention of end-organ damage in women with HDP and describe the role and contribution of anesthesiologists as part of a multidisciplinary care team.

PRINCIPAL FINDINGS

Hypertensive disorders of pregnancy can have variable presentations with clinical signs and symptoms that often do not correlate with the underlying severity and progression of the disease. Failure of timely diagnosis and treatment contributes significantly to adverse maternal (neurologic complications, pulmonary edema, and postpartum hemorrhage) and neonatal (respiratory and neurologic complications and stillbirth) outcomes. In the Canadian context, improvements in medical care have led to better maternal and neonatal outcomes. Timing of delivery is crucial in balancing maternal risks and fetal benefits of ongoing pregnancy. Evidence-based SOGC guidelines regarding diagnosis and management of HDP address many aspects of clinical care relevant to anesthesiologists, who have an important role in the multidisciplinary care team.

CONCLUSIONS

Hypertensive disorders of pregnancy are on the rise worldwide, and this trend is expected to continue. The major contributors to maternal mortality are failure to recognize HDP promptly or to treat the condition adequately. It is essential that anesthesiologists understand the disease process and acquire knowledge of the guidelines governing current obstetrical care in order to provide evidence-based multidisciplinary quality care to these patients. Anesthetic management helps prevent potentially deleterious maternal and fetal outcomes.

Protective Role of Maternal P.VAL158MET Catechol-O-Methyltransferase Polymorphism against Early-Onset Preeclampsia and its Complications

Background

Up until now there have been contradictory data about the association between p.Val158Met catechol-O-methyltransferase (COMT) polymorphism and risk of preeclampsia (PE). The goal of this study was to assess the potential correlation between p.Val158Met COMT polymorphism and risk of early-onset PE, risk of a severe form of early-onset PE, as well as risk of small-for-gestational-age (SGA) complicating PE.

Methods

The study included 47 early-onset PE patients and 47 control cases. Forty-seven early-onset PE patients were grouped by disease severity (33 patients with a severe form and 14 patients without severe features) and secondly by size for gestational age (12 patients with appropriate-for-gestational-age (AGA) and 35 patients with SGA size). p.Val158Met polymorphism was genotyped by PCR-RFLP analysis.

Results

Allele analysis showed significant difference in COMT allele distribution between early-onset PE and control group as well as early-onset PE SGA and controls (p=0.04057 and p=0.0411 respectively). A statistically significant distribution difference between the severe form and form without severe features of early-onset PE patients was not observed (p>0.05). The highest difference observed was in the allele recessive model where COMT MetMet genotype was associated with decreased risk of early-onset PE (OR=0.281; 95%CI = 0.092–0.7836) and PE complications including severe early-onset PE (OR= 0.304; 95%CI=0.086–0.944) and SGA early-onset PE (OR=0.284; 95%CI=0.081–0.874).

Conclusions

COMT may be used as a candidate gene for early-onset PE and its severe form and SGA complications.

Association between Placental Lesions, Cytokines and Angiogenic Factors in Pregnant Women with Preeclampsia

Preeclampsia (PE) is considered the leading cause of maternal and perinatal morbidity and mortality. The placenta seems to play an essential role in this disease, probably due to factors involved in its formation and development. The present study aimed to investigate the association between placental lesions, cytokines and angiogenic factors in pregnant women with preeclampsia (PE). We evaluated 20 normotensive pregnant women, 40 with early-onset PE and 80 with late-onset PE. Placental samples were analyzed for histopathology, immunohistochemistry and determination of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-10 (IL-10), transforming growth factor-beta 1 (TGF-β₁), tumor necrosis factor-alpha (TNF-α), placental growth factor (PlGF), vascular endothelial growth factor (VEGF), fms-like tyrosine-kinase-1 (Flt-1) and endoglin (Eng) levels. Higher percentages of increased syncytial knots and increased perivillous fibrin deposits, and greater levels of TNF-α, TGF-β1and Flt-1 were detected in placentas from early-onset PE. Levels of IL-10, VEGF and PlGF were decreased in PE versus normotensive placentas. Both the TNF-α/IL-10 and sFlt-1/PlGF ratios were higher in placental homogenate of early-onset PE than late-onset PE and control groups. The more severe lesions and the imbalance between TNF-α/IL-10 and PlGF/sFlt-1 in placentas from early-onset PE allows differentiation of early and late-onset PE and suggests higher placental impairment in early-onset PE.

Amnion as a surrogate tissue reporter of the effects of maternal preeclampsia on the fetus

BACKGROUND

Preeclampsia, traditionally characterized by high blood pressure and proteinuria, is a common pregnancy complication, which affects 2-8 % of all pregnancies. Although children born to women with preeclampsia have a higher risk of hypertension in later life, the mechanism of this increased risk is unknown. DNA methylation is an epigenetic modification that has been studied as a mediator of cellular memory of adverse exposures in utero. Since each cell type in the body has a unique DNA profile, cell subtype composition is a major confounding factor in studies of tissues with heterogeneous cell types. The best way to avoid this confounding effect is by using purified cell types. However, using purified cell types in large cohort translational studies is difficult. The amnion, the inner layer of the fetal membranes of the placenta, is derived from the epiblast and consists of two cell types, which are easy to isolate from the delivered placenta. In this study, we demonstrate the value of using amnion samples for DNA methylation studies, revealing distinctive patterns between fetuses exposed to proteinuria or hypertension and fetuses from normal pregnancies.

RESULTS

We performed a genome-wide DNA methylation analysis, HpaII tiny fragment Enrichment by Ligation-mediated PCR (HELP)-tagging, on 62 amnion samples from the placentas of uncomplicated, normal pregnancies and from those with complications of preeclampsia or hypertension. Using a regression model approach, we found 123, 85, and 99 loci with high-confidence hypertension-associated, proteinuria-associated, and hypertension- and proteinuria-associated DNA methylation changes, respectively. A gene ontology analysis showed DNA methylation changes to be selecting genes with different biological processes in exposure status. We also found that these differentially methylated regions overlap loci previously reported as differentially methylated regions in preeclampsia.

CONCLUSIONS

Our findings support prior observations that preeclampsia is associated with changes of DNA methylation near genes that have previously been found to be dysregulated in preeclampsia. We propose that amniotic membranes represent a valuable surrogate fetal tissue on which to perform epigenome-wide association studies of adverse intrauterine conditions.

Total oxidative and anti-oxidative status, and ADAMTS-12 levels in placenta previa and early-onset severe preeclampsia

AIM

This study was carried out due to the discussions in the literature stating that the inverse association between placenta previa (PP) and preeclampsia (PE). The aim of this study was to determine whether total antioxidant status (TAS), and total oxidant status (TOS) and ADAMTS-12 levels differ among early-onset (<34th gestational week) severe PE (EOS-PE), PP and uncomplicated pregnancies.

METHODS

In this case-control study, serum samples obtained from 26 pregnant with EOS-PE, 31 pregnant with PP, and 32 healthy patients with uncomplicated pregnancies (control group).

RESULTS

TOS levels were significantly higher in the EOS-PE than in the control group and PP groups (p=0.002, p=0.05, respectively). TAS levels were significantly lower in the EOS-PE than in the control (p<0.001). Although TAS levels were lower in the EOS-PE group than in the PP group, the differences were not statistically significant (p=0.09). There were no significant differences in the ADAMTS-12 levels of the groups.

DISCUSSION

The data in this study suggested that the balance between oxidative and anti-oxidative substances were comparable and normal in pregnancies complicated by PP when compared to normal pregnancies without placentation abnormality. In support of this, we encountered no case with PE and fetal growth restriction in our study groups suggesting normal placental angiogenesis. Contrarily, EOS-PE was associated with decreased TAS and increased TOS levels in the maternal serum.

Pre-pregnancy maternal obesity and the risk of preterm preeclampsia in the American primigravida

OBJECTIVE

To estimate the risk of preterm preeclampsia in primiparous women by pre-pregnancy obesity class.

METHODS

A retrospective cohort study of primiparous women with singleton gestations was performed for deliveries from January 2003 to April 2014. Cases were stratified by delivery occurring either at ≥ 37 weeks or < 37 weeks. Pre-pregnancy maternal obesity was defined as a body mass index (BMI) ≥ 30 kg/m(2) . World Health Organization criteria were used to define BMI class of obesity. Multinomial logistic regression modeling estimated the association between term and preterm preeclampsia and pre-pregnancy obesity.

RESULTS

Of 28,361 women with complete pre-pregnancy BMI data, 2,588 women (9.1%) had a diagnosis of preeclampsia. Women who developed preeclampsia prior to 37 weeks (n = 784) were more likely to be women with obesity compared to women who developed preeclampsia after 37 weeks (33.1% vs. 25.3%, P = 0.0001). Compared to normal-weight women without preeclampsia, the risk of preterm preeclampsia increased proportionally with pre-pregnancy obesity class, with women with a BMI ≥ 40 kg/m(2) having the greatest risk (RR 5.23, 95% CI: 3.86-7.09, P <0.001).

CONCLUSIONS

The risk of preterm preeclampsia increased significantly as the severity of maternal pre-pregnancy obesity increased. Reduction in maternal pre-pregnancy BMI may be protective in mitigating such risk.

The impact of early- and late-onset preeclampsia on umbilical cord blood cell populations

Pregnancies complicated by preeclampsia (PE) are characterised by an enhanced maternal and fetal inflammatory response with increased numbers of leukocytes in maternal peripheral blood. The impact of PE on newborn umbilical cord blood cell (UCBC) populations however, has been scarcely studied. We hypothesise that PE deranges fetal haematopoiesis and subsequently UCBC populations. Therefore, the objective of this study was to investigate newborn umbilical cord blood cell populations in early- (EOPE) and late-onset PE (LOPE). A secondary cohort analysis in The Rotterdam Periconceptional Cohort was conducted comprising 23 PE cases, including 11 EOPE and 12 LOPE, and 195 controls, including 153 uncomplicated and 23 fetal growth restriction- and 19 preterm birth complicated controls. UCBC counts and differentials were quantified by flow cytometry and analysed as main outcome measures. Multivariable regression analysis revealed associations of EOPE with decreased leucocyte- (monocytes, neutrophils, eosinophils, immature granulocytes) and thrombocyte counts and increased NRBC counts (all p<0.05). EOPE remained associated with neutrophil- (β-0.92, 95%CI -1.27,-0.57, p<0.001) and NRBC counts (β1.11, 95%CI 0.27,1.95, p=0.010) after adjustment for gestational age and birth weight. LOPE did not reveal any significant association. We conclude that derangements of fetal haematopoiesis, in particular of neutrophil- and NRBC counts, are associated with EOPE only, with a potential impact for future health of the offspring. This heterogeneity in UCBC should be considered as confounder in epigenetic association studies examining EOPE.

Preeclampsia and the Risk of Future Vascular Disease and Mortality: A Review

INTRODUCTION

Preeclampsia increases a woman's long-term risk of vascular disease and/or death including chronic hypertension, myocardial infarction, heart failure, stroke, and venous thromboembolism. The literature suggests that maternity care providers may be unaware of this association.

METHODS

A database search was conducted examining the long-term effects of hypertensive disorders of pregnancy using MEDLINE, Scopus, CINAHL, ISI Web of Knowledge, and the Cochrane Database of Systematic Reviews. Inclusion criteria were: 1) English language, 2) peer-reviewed journals, 3) January 2000 to July 2015, 4) systematic reviews with or without meta-analyses, and 5) studies that addressed the relationship between hypertensive disorders of pregnancy and vascular disease such as hypertension, cardiovascular disease (CVD), and cerebrovascular diseases.

RESULTS

Three systematic reviews with meta-analysis qualified for this review. They represented 48 unique studies from 20 countries and included a total of 3,598,601 women. Preeclampsia was associated with a 3-fold increased risk for developing chronic hypertension. Compared with normotensive women, those with preeclampsia experienced double the risk, or more, for CVD or CVD-related mortality. Preeclampsia was also associated with approximately double the risk for fatal or nonfatal stroke.

DISCUSSION

Preeclampsia is associated with an increased risk for future chronic hypertension, CVD, cerebrovascular disease, and death. While evidence shows that women with cardiac risk factors may have a higher chance of developing preeclampsia, many women with preeclampsia have no CVD risk factors. Measures to prevent preeclampsia such as calcium supplementation for women with low calcium intake and low-dose aspirin for women with a history of more than one incident of preeclampsia or a preterm birth associated with preeclampsia are supported by evidence. Reduction of modifiable risks associated with CVD before, during, and after pregnancy is recommended. All care providers and women should be educated regarding these risks and the importance of pregnancy history to future health.

Association between decreased plasma levels of soluble human leukocyte antigen-G and severe pre-eclampsia

OBJECTIVE

The aim of this study was to investigate the levels of different isoforms of soluble human leukocyte antigen-G (sHLA-G) in maternal plasma during early and late pregnancy, and to investigate the expression of sHLA-G isoforms in women with early or late-onset severe preeclampsia.

METHODS

This prospective, nested, case-control study was performed in 24 early-onset severe preeclamptic, 34 late-onset severe preeclamptic, and 74 uncomplicated pregnant women. Plasma levels of sHLA-G1/5 were measured using ELISA.

RESULTS

Plasma sHLA-G1 levels in women with late-onset severe preeclampsia were markedly lower compared with normal controls (median: 0 vs. 1.22 ng/mL) at the first trimester, and plasma sHLA-G1 levels in women with early-onset severe preeclampsia were markedly lower compared with normal controls at the second (median: 0 vs. 1.24 ng/mL) and third (median: 0 vs. 1.34 ng/mL) trimesters. There was no difference between the late-onset and early-onset groups at three trimesters. As for sHLA-G5, there was no difference in concentrations among the three groups at any time point. However, compared with controls, more women with early- or late-onset severe preeclampsia had undetectable sHLA-G5 levels in the first (71.4% and 76.2% vs. 14.1%), second (75.0% and 73.3% vs. 19.0%), and third (100.0% and 70.4% vs. 14.8%, respectively) trimester (all P<0.05). sHLA-G1 levels in the first (odds ratio [OR]=0.254, 95% confidence interval [CI]=0.109-0.591, P=0.010), second (OR=0.315, 95% CI=0.158-0.627, P=0.001), and third (OR=0.170, 95% CI=0.054-0.533, P=0.002) trimester was a risk factor for severe preeclampsia.

CONCLUSION

Severe preeclampsia was associated with low/undetectable maternal plasma levels of sHLA-G. Low sHLA-G1 levels might be a risk marker for severe preeclampsia.

Maternal Cardiovascular Function in Normal Pregnancy

The aim of this study was to investigate cardiac functional status in pregnancy using a comprehensive approach taking into account the simultaneous changes in loading and geometry, as well as maternal age and anthropometric indices. This was a prospective cross-sectional study of 559 nulliparous pregnant women assessed at 4 time points during pregnancy and at 1 year postpartum. All women underwent conventional echocardiography and tissue Doppler velocities and strain rate analysis at multiple cardiac sites. Mean arterial pressure and total vascular resistance index significantly decreased (both P <0.001) during the first 2 trimesters of pregnancy and increased thereafter. Stroke volume index and cardiac index showed the opposite trend compared with mean arterial pressure and total vascular resistance index (both P <0.05). Myocardial and ventricular function were significantly enhanced in the first 2 trimesters but progressively declined thereafter. By the end of pregnancy, significant chamber diastolic dysfunction and impaired myocardial relaxation was evident in 17.9% and 28.4% of women, respectively, whereas myocardial contractility was preserved. There was full recovery of cardiac function at 1 year postpartum. Cardiovascular changes during pregnancy are thought to represent a physiological adaptation to volume overload. The findings of a drop in stroke volume index, impaired myocardial relaxation with diastolic dysfunction, and a tendency toward eccentric remodeling in a significant proportion of cases at term are suggestive of cardiovascular maladaptation to the volume-overloaded state in some apparently normal pregnancies. These unexpected cardiovascular findings have important implications for the management of both normal and pathological pregnancy states.

Placental levels of total oxidative and anti-oxidative status, ADAMTS-12 and decorin in early- and late-onset severe preeclampsia

OBJECTIVE

Preeclampsia (PE), can be classified according to the timing of disease onset: early-onset PE occurs before the 34th gestational week and late-onset PE occurs in the 34th gestational week or later. The aim of this study was to determine whether total antioxidant status (TAS), and total oxidant status (TOS), ADAMTS-12 and decorin levels differ among early-onset severe PE (EOS-PE), late-onset severe PE (LOS-PE) and uncomplicated pregnancies.

METHODS

In this case-control study, placental samples obtained from 25 pregnant patients with EOS-PE, 26 pregnant patients with LOS-PE and 28 healthy patients with uncomplicated pregnancies (control group).

RESULTS

Placenta levels of decorin and TOS were significantly higher and TAS was significantly lower in the EOS-PE and LOS-PE groups than in the control group. These alterations were more prominent in patients with EOS-PE than in patients with LOS-PE. There were no significant differences in the ADAMTS-12 levels of the groups.

CONCLUSION

The distinctly higher rate of negative perinatal outcomes in both EOS-PE and LOS-PE patients is well evidenced. However, the main questions that need to be answered are whether the only difference between these two diseases is the time of their onset and whether the only difference between them with respect to fetal morbidity and mortality is prematurity.

Role of vitamin D and sFlt-1/PlGF ratio in the development of early- and late-onset preeclampsia

BACKGROUND

The imbalanced production of placental biomarkers and vitamin D deficiency have been proposed as risk factors for the development of preeclampsia (PE). However, little is known about the relationship between them and their role in early- versus late-onset PE. The objectives were to assess the role of 25-hydroxyvitamin D [25(OH)D] concentrations and the soluble fms-like tyrosine kinase 1 (sFlt-1) to placental growth factor (PlGF) ratio in the development of early- and late-onset PE; and to evaluate the relationship between 25(OH)D and the biomarkers.

METHODS

A retrospective, full-blinded cohort study was conducted at the Obstetric Emergency Service of a tertiary care hospital. Pregnant women (n=257) attending obstetric triage with suspicion of PE were included. sFlt-1, PlGF and 25(OH)D concentrations were measured by electrochemoluminescence (ECLIA) immunoassay and pregnancy outcome (development of PE) was registered from patients records.

RESULTS

PE women showed lower 25(OH)D concentrations at clinical presentation than non-PE women (median: 35.0 nmol/L and 39.6 nmol/L, respectively; p=0.027). Women with 25(OH)D levels <50 nmol/L experienced an increased risk of developing late-onset PE [odds ratio (OR) 4.6, 95% confidence interval (CI) 1.4-15], but no association was found for early-onset PE. However, a sFlt-1/PlGF ratio above the corresponding cutpoints increased the risk of developing both early- and late-onset PE [ORs 58 (95% CI 11-312) and 12 (95% CI 5.0-27), respectively]. No association was found between 25(OH)D levels and sFlt-1/PlGF ratio.

CONCLUSIONS

Low vitamin D status in women with suspected late-onset PE increases the risk of imminent development of the disease.

Prognostic Value of Cardiovascular Disease Risk Factors Measured in the First-Trimester on the Severity of Preeclampsia

Recent studies have suggested that preeclampsia and cardiovascular disease may share common mechanisms. The purpose of this prospective nested case-controlled study was to characterize a variety of cardiovascular disease risk factors measured during the first trimester of pregnancy in predicting subsequent outcomes and the severity of preeclampsia.We ascertained the severity of preeclampsia at the onset of the disease, and the presence of intrauterine growth restriction (IUGR). We compared first trimester maternal serum cardiovascular disease risk factors in preeclampsia subjects versus normal pregnancies, early-onset versus late-onset preeclampsia, and preeclampsia with IUGR versus without IUGR. To identify the prognostic value of independent predictors on the severity of preeclampsia, we calculated the area under the receiver operating characteristics curve (AUC) using logistic regression analysis.There were 134 cases of preeclampsia and 150 uncomplicated pregnancies, and preeclampsia cases were classified as early-onset (53 cases) or late-onset (81 cases), or as with IUGR (44 cases) or without IUGR (90 cases). Among the cardiovascular disease risk factors, maternal serum high-sensitive C-reactive protein (hsCRP) and homocysteine were predictors of both early-onset preeclampsia and preeclampsia with IUGR. For the detection of early onset preeclampsia or preeclampsia with IUGR, the AUC for the combination model (0.943 and 0.952, respectively) was significantly higher than with serum hsCRP or serum homocysteine only.Patients with preeclampsia can be subdivided into different severities according to time of onset and fetal weight. Cardiovascular risk factors distinguish a subgroup of these patients.

Immune Mechanisms Linking Obesity and Preeclampsia

Preeclampsia (PE) is characterized by hypertension occurring after the twentieth week of pregnancy. It is a significant contributor to maternal and perinatal morbidity and mortality in developing countries and its pervasiveness is increasing within developed countries including the USA. However, the mechanisms mediating the pathogenesis of this maternal disorder and its rising prevalence are far from clear. A major theory with strong experimental evidence is that placental ischemia, resulting from inappropriate remodeling and widening of the maternal spiral arteries, stimulates the release of soluble factors from the ischemic placenta causing maternal endothelial dysfunction and hypertension. Aberrant maternal immune responses and inflammation have been implicated in each of these stages in the cascade leading to PE. Regarding the increased prevalence of this disease, it is becoming increasingly evident from epidemiological data that obesity, which is a state of chronic inflammation in itself, increases the risk for PE. Although the specific mechanisms whereby obesity increases the rate of PE are unclear, there are strong candidates including activated macrophages and natural killer cells within the uterus and placenta and activation in the periphery of T helper cells producing cytokines including TNF-α, IL-6 and IL-17 and the anti-angiogenic factor sFlt-1 and B cells producing the agonistic autoantibodies to the angiotensin type 1 receptor (AT1-aa). This review will focus on the immune mechanisms that have been implicated in the pathogenesis of hypertension in PE with an emphasis on the potential importance of inflammatory factors in the increased risk of developing PE in obese pregnancies.

Combination of serum angiopoietin-2 and uterine artery Doppler for prediction of preeclampsia

The aim of this study was to determine the predictive value of the combination of serum angiopoietin-2 (Ang-2) levels and uterine artery Doppler for the detection of preeclampsia in women at 16-18 weeks of gestation and to identify other pregnancy complications that could be predicted with these combined tests. Maternal serum Ang-2 levels were measured, and uterine artery Doppler was performed in 400 pregnant women. The main outcome was preeclampsia. The predictive values of this combination were calculated. Twenty-five women (6.3%) developed preeclampsia. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of uterine artery Doppler combined with serum Ang-2 levels for the prediction of preeclampsia were 24.0%, 94.4%, 22.2% and 94.9%, respectively. For the prediction of early-onset preeclampsia, the sensitivity, specificity, PPV and NPV were 57.1%, 94.1%, 14.8% and 99.2%, respectively. Patients with abnormal uterine artery Doppler and abnormal serum Ang-2 levels (above 19.5 ng ml(-1)) were at higher risk for preterm delivery (relative risk=2.7, 95% confidence interval 1.2-5.8). Our findings revealed that the combination of uterine artery Doppler and serum Ang-2 levels at 16-18 weeks of gestation can be used to predict early-onset preeclampsia but not overall preeclampsia. Thus, this combination may be a useful early second trimester screening test for the prediction of early-onset preeclampsia.

Increased risk for the development of preeclampsia in obese pregnancies: weighing in on the mechanisms

Preeclampsia (PE) is a pregnancy-specific disorder typically presenting as new-onset hypertension and proteinuria. While numerous epidemiological studies have demonstrated that obesity increases the risk of PE, the mechanisms have yet to be fully elucidated. Growing evidence from animal and human studies implicate placental ischemia in the etiology of this maternal syndrome. It is thought that placental ischemia is brought about by dysfunctional cytotrophoblast migration and invasion into the uterus and subsequent lack of spiral arteriole widening and placental perfusion. Placental ischemia/hypoxia stimulates the release of soluble placental factors into the maternal circulation where they cause endothelial dysfunction, particularly in the kidney, to elicit the clinical manifestations of PE. The most recognized of these factors are the anti-angiogenic sFlt-1 and pro-inflammatory TNF-α and AT1-AA, which promote endothelial dysfunction by reducing levels of the provasodilator nitric oxide and stimulating production of the potent vasoconstrictor endothelin-1 and reactive oxygen species. We hypothesize that obesity-related metabolic factors increase the risk for developing PE by impacting various stages in the pathogenesis of PE, namely, 1) cytotrophoblast migration and placental ischemia; 2) release of soluble placental factors into the maternal circulation; and 3) maternal endothelial and vascular dysfunction. This review will summarize the current experimental evidence supporting the concept that obesity and metabolic factors like lipids, insulin, glucose, and leptin affect placental function and increase the risk for developing hypertension in pregnancy by reducing placental perfusion; enhancing placental release of soluble factors; and by increasing the sensitivity of the maternal vasculature to placental ischemia-induced soluble factors.

Placental Aromatase Is Deficient in Placental Ischemia and Preeclampsia

Introduction

Preeclampsia is a maternal hypertensive disorder with uncertain etiology and a leading cause of maternal and fetal mortality worldwide, causing nearly 40% of premature births delivered before 35 weeks of gestation. The first stage of preeclampsia is characterized by reduction of utero-placental blood flow which is reflected in high blood pressure and proteinuria during the second half of pregnancy. In human placenta androgens derived from the maternal and fetal adrenal glands are converted into estrogens by the enzymatic action of placental aromatase. This implies that alterations in placental steroidogenesis and, subsequently, in the functionality or bioavailability of placental aromatase may be mechanistically involved in the pathophysiology of PE.

Methods

Serum samples were collected at 32–36 weeks of gestation and placenta biopsies were collected at time of delivery from PE patients (n = 16) and pregnant controls (n = 32). The effect of oxygen tension on placental cells was assessed by incubation JEG–3 cells under 1% and 8% O₂ for different time periods, Timed-mated, pregnant New Zealand white rabbits (n = 6) were used to establish an in vivo model of placental ischemia (achieved by ligature of uteroplacental vessels). Aromatase content and estrogens and androgens concentrations were measured.

Results

The protein and mRNA content of placental aromatase significantly diminished in placentae obtained from preeclamptic patients compared to controls. Similarly, the circulating concentrations of 17-β-estradiol/testosterone and estrone/androstenedione were reduced in preeclamptic patients vs. controls. These data are consistent with a concomitant decrease in aromatase activity. Aromatase content was reduced in response to low oxygen tension in the choriocarcinoma JEG–3 cell line and in rabbit placentae in response to partial ligation of uterine spiral arteries, suggesting that reduced placental aromatase activity in preeclamptic patients may be associated with chronic placental ischemia and hypoxia later in gestation.

Conclusions

Placental aromatase expression and functionality are diminished in pregnancies complicated by preeclampsia in comparison with healthy pregnant controls.

Elevation of (Pro)Renin and (Pro)Renin Receptor in Preeclampsia

OBJECTIVE

Preeclampsia (preE), a syndrome of hypertension, proteinuria, and edema, has many elusive triggers. The renin-angiotensin system has been implicated in preE pathogenesis. In this study, we test the hypothesis that (pro)renin levels are increased in preE patients and that levels of (pro)renin and (pro)renin receptor ((P)RR) are elevated in a rat model of preE.

METHODS

We recruited 30 preE and 43 normal pregnant consenting patients. We used normally pregnant rats (NP, n = 10) and pregnant rats receiving weekly injections of desoxycorticosterone acetate and whose drinking water was replaced with 0.9% saline (preE, n = 10). Plasma and placental levels of (pro)renin were assayed by ELISA. Placental and kidney (P)RR was measured both by immunoblotting and immunohistochemistry.

RESULTS

The mean plasma (pro)renin of 27.1±5.2 in preE patients differs from that in patients without preE: 14.8±5.2 ng Ang I/ml/hour (P < 0.0001). In rats, both plasma (NP: 22.7±4.3 and preE: 49.2±10.0 ng Ang I/ml/hour) and placental (NP: 152±24 and preE: 302±39 ng/g tissue) levels of (pro)renin were higher (P < 0.001) in preE compared to NP rats. (P)RR expression was greater (P < 0.05) in placental tissue of preE rats, while kidney (P)RR expression was similar.

CONCLUSION

Elevated levels of circulating (pro)renin have been observed in preE patients and in a rat model of preE. We also found the increased expression of placental (P)RR in preE rats.

Strong ion and weak acid analysis in severe preeclampsia: potential clinical significance

BACKGROUND

The influence of common disturbances seen in preeclampsia, such as changes in strong ions and weak acids (particularly albumin) on acid-base status, has not been fully elucidated. The aims of this study were to provide a comprehensive acid-base analysis in severe preeclampsia and to identify potential new biological predictors of disease severity.

METHODS

Fifty women with severe preeclampsia, 25 healthy non-pregnant- and 46 healthy pregnant controls (26-40 weeks' gestation), were enrolled in this prospective case-control study. Acid-base analysis was performed by applying the physicochemical approach of Stewart and Gilfix.

RESULTS

Mean [sd] base excess was similar in preeclamptic- and healthy pregnant women (-3.3 [2.3], and -2.8 [1.5] mEq/L respectively). In preeclampsia, there were greater offsetting contributions to the base excess, in the form of hyperchloraemia (BE(Cl) -2 [2.3] vs -0.4 [2.3] mEq/L, P<0.001) and hypoalbuminaemia (BE(Alb) 3.6 [1] vs 2.1 [0.8] mEq/L, P<0.001). In preeclampsia, hypoalbuminaemic metabolic alkalosis was associated with a non-reassuring/abnormal fetal heart tracing (P<0.001). Quantitative analysis in healthy pregnancy revealed respiratory and hypoalbuminaemic alkalosis that was metabolically offset by acidosis, secondary to unmeasured anions and dilution.

CONCLUSIONS

While the overall base excess in severe preeclampsia is similar to that in healthy pregnancy, preeclampsia is associated with a greater imbalance offsetting hypoalbuminaemic alkalosis and hyperchloraemic acidosis. Rather than the absolute value of base excess, the magnitude of these opposing contributors may be a better indicator of the severity of this disease. Hypoalbuminaemic alkalosis may also be a predictor of fetal compromise.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov: NCT 02164370.

Placental lipase expression in pregnancies complicated by preeclampsia: a case-control study

BACKGROUND

Preeclampsia (PE) is associated with maternal and neonatal morbidity and mortality. In PE, the physiological hyperlipidaemia of pregnancy is exaggerated. The purpose of this study was to examine the expression of adipose triglyceride lipase (ATGL), hormone sensitive lipase (HSL), lipoprotein lipase (LPL) and endothelial lipase (EL) in pregnancies complicated by PE.

METHODS

Placentae were collected from 16 women with PE and 20 women with uncomplicated pregnancies matched for maternal prepregnancy BMI and gestational age of delivery. Gene and protein expression of the placental lipases were measured by Q-PCR and Western blot. DNA methylation of the promoter of LPL was assessed by bisulfite sequencing. Lipase localisation and activity were analysed.

RESULTS

Gene expression of all lipases was significantly reduced, as was HSL protein level in women with PE. All lipases were localised to trophoblasts and endothelial cells in PE and control placentae. There was no difference in methylation of the LPL promoter between PE and control placentae. Lipase activity was not altered in placentae from women with PE.

CONCLUSION

These results suggest that the decreased placental lipase gene but not protein expression or lipase activity, which is associated with late-onset PE is not a major contributor to the abnormal lipids seen in PE.

Diagnosis and Treatment of Hypertensive Pregnancy Disorders. Guideline of DGGG (S1-Level, AWMF Registry No. 015/018, December 2013)

Purpose: Official guideline published and coordinated by the German Society of Gynecology and Obstetrics (DGGG). Hypertensive pregnancy disorders contribute significantly to perinatal as well as maternal morbidity and mortality worldwide. Also in Germany these diseases are a major course for hospitalization during pregnancy, iatrogenic preterm birth and long-term cardiovascular morbidity. Methods: This S1-guideline is the work of an interdisciplinary group of experts from a range of different professions who were commissioned by DGGG to carry out a systematic literature search of positioning injuries. Members of the participating scientific societies develop a consensus in an informal procedure. Afterwards the directorate of the scientific society approves the consensus. Recommendations: This guideline summarizes the state-of-art for classification, risk stratification, diagnostic, treatment of hypertensive pregnancy disorders.

Plasma F2-isoprostane class VI isomers at 12-18 weeks of pregnancy are associated with later occurrence of preeclampsia

Preeclampsia (PE) has long been associated with early oxidative stress, although the symptoms occur later in pregnancy. We have hypothesized that the oxidative stress in PE, as characterized by the presence of F2-isoprostane (F2-isoP) isomers in late pregnancy, should already be present in plasma at the first regular visit of the obstetrical follow-up. There are 64 possible isomers of F2-isoPs derived from the oxidation of arachidonic acid (AA), but only one of these isomers has been investigated so far in PE, the classical 8-iso-PGF2α. Here, we have investigated two regioisomers of class III (8-iso-15(R)-PGF2α and 8-iso-PGF2α) and a mix of two isomers of class VI ((±)5-iPF2α-VI) in plasma samples collected prospectively at 12-18 weeks from normotensive controls (n = 60) and pregnant mothers who developed PE later in pregnancy (n = 33). The plasma samples were subjected to alkaline hydrolysis followed by liquid-liquid extraction to extract total F2-isoPs for later quantification by HPLC-MS/MS. The F2-isoPs were normalized to either plasma volume or polyunsaturated fatty acid (PUFA) levels measured by GC-FID in plasma phospholipids. Early in pregnancy, only the class VI F2-isoP isomers were found at concentrations significantly higher in women developing PE later in pregnancy (+13%; p = 0.0074). Normalization of F2-isoPs to their substrate, AA, or the omega-3 to omega-6 ratio improved the predictability of PE as determined by receiver operating characteristic (from area under the curve of 0.67 to 0.68 and 0.70 respectively). Interestingly, omega-3 fatty acids were 25% higher in the control group than in the PE group (P = 0.0225). Omega-6 PUFAs correlated with F2-Isop isomers only in cases of PE (r > 0.377; P >0.03, Spearman correlation). In sum, this study indicates that specific isomers of class VI are significant predictors of PE. This work also suggests that F2-isoP isomers are not all generated and eliminated to the same extent and are influenced by the PUFA composition of plasma phospholipids.

Controlled direct effects of preeclampsia on neonatal health after accounting for mediation by preterm birth

BACKGROUND

Preeclampsia is characterized by alterations in angiogenic factors that may increase neonatal morbidity independent of preterm birth.

METHODS

We estimated the controlled direct effect of preeclampsia on neonatal outcomes independent of preterm birth among 200,103 normotensive and 10,507 preeclamptic singleton pregnancies in the Consortium on Safe Labor (2002-2008). Marginal structural models with stabilized inverse probability weights accounted for potential confounders in the pathway from preeclampsia to preterm birth to neonatal outcomes, including mediator-outcome confounders related to preeclampsia status, such as cesarean delivery. Controlled direct effects of preeclampsia on perinatal mortality, small for gestational age (SGA), neonatal intensive care unit (NICU) admission, respiratory distress syndrome, transient tachypnea of the newborn, anemia, apnea, asphyxia, peri- or intraventricular hemorrhage, and cardiomyopathy were estimated for the hypothesized intervention of term delivery for all infants.

RESULTS

When delivery was set at ≥37 weeks, preeclampsia increased the odds of perinatal mortality (odds ratio = 2.2 [95% confidence interval = 1.1-4.5], SGA = (1.9 [1.8-2.1]), NICU admission (1.9 [1.7-2.1]), respiratory distress syndrome (2.8 [2.0-3.7], transient tachypnea of the newborn (1.6 [1.3-1.9]), apnea (2.2 [1.6-3.1]), asphyxia (2.7 [1.5-4.9]), and peri- or intraventricular hemorrhage (3.2 [1.4-7.7]). No direct effect of preeclampsia at term was observed for anemia or cardiomyopathy. Our results appear robust in the presence of moderate confounding, and restriction to severe preeclampsia yielded similar findings.

CONCLUSION

Preeclampsia was directly associated with adverse neonatal outcomes beyond morbidity mediated by preterm birth. Although severe neonatal outcomes were less common at later gestational ages, marginal structural models suggested elevated neonatal risk due to preeclampsia even if it was possible to deliver all infants at term.

Preeclampsia in twin pregnancies: association with selective intrauterine growth restriction

OBJECTIVE

To identify the association between preeclampsia (PE) and selective intrauterine growth restriction (sIUGR) in twin pregnancies.

METHODS

This was a retrospective cohort study of 1004 twin pregnancies from 2008 to 2014. We specifically compared the incidence, clinical characteristics and outcomes of PE between sIUGR and normal-growth twin pregnancies.

RESULTS

PE occurred more frequently in sIUGR pregnancies [29.0% (51/176)] than in normal-growth twin pregnancies [13.1% (99/756), p < 0.001, adjusted odds ratio 3.29]. Among sIUGR, the incidence of PE was significantly higher in dichorionic (DC) pregnancies (37.5%, 30/80) than in monochorionic (MC) pregnancies (21.9%, 21/96). The rates of onset at <32 weeks (p = 0.045) and of severe PE (p = 0.025) were higher in sIUGR pregnancies with PE. The systolic blood pressure was also higher in sIUGR pregnancies with PE (152.6 ± 11.8 mmHg) than in normal-growth pregnancies with PE (148.0 ± 8.2 mmHg) (p = 0.042). Additionally, more sIUGR pregnancies were delivered at 32-36 weeks (p = 0.001), and fewer were delivered at ≥36 weeks (p < 0.001). Moreover, the prevalence of severe neonatal asphyxia was higher in sIUGR pregnancies with PE than in normal-growth pregnancies with PE (8.8% versus 2.5%, p = 0.020).

CONCLUSIONS

sIUGR is associated with increased odds of developing severe PE in twin pregnancies, leading to poorer perinatal outcomes.

First-trimester maternal cell microRNA is a superior pregnancy marker to immunological testing for predicting adverse pregnancy outcome

Patients at risk of immune-mediated pregnancy complications have historically relied on the use of peripheral blood immunological assays for diagnosis and pregnancy monitoring. However, these tests often fail to identify many at-risk patients, achieving moderately predictive receiver operating characteristic (ROC) curve AUCs of 0.60-0.70. We previously demonstrated that a microRNA panel comprising 30 microRNAs successfully predicts pregnancy outcome in the first trimester. In our current study we constructed a smaller, more clinically useful seven-microRNA panel from the original panel of 30 microRNAs with equivalent sensitivity and specificity. To select optimal microRNAs for a smaller panel, quantitative RT-PCR on 30 microRNAs was first performed on 48 patients (191 samples) with concurrent immunological testing: TNFα/Il-10 ratio, IFNγ/Il-10, CD56+16+%, NK 50:1 cytotoxicity and T regulatory cells. MicroRNAs were separated into clusters associated with: Th1/Th2 response; T regulatory cell percent; pregnancy risk; treatment response. Seven most differentially expressed microRNAs were selected. The seven microRNA scoring system was then applied to 39 patient samples in the first trimester of pregnancy (19 healthy deliveries, 8 miscarriages, 12 preeclampsia [7 late-onset and 5 early-onset]) and 20 samples in the preconception period (2-10 weeks before conception). Predictive value was assessed. ROC curves for the seven-microRNA panel achieved AUC 0.92 for miscarriage and 0.90 for preeclampsia (blood drawn 34.9±19.2 days post-implantation). For samples measured preconception, ROC curve analysis demonstrated AUC 0.81 for adverse pregnancy outcome. Maternal PBMC microRNA can identify high-risk patients likely to benefit from immunotherapy with improved sensitivity and specificity compared with standard immune assays.

Full-length human placental sFlt-1-e15a isoform induces distinct maternal phenotypes of preeclampsia in mice

OBJECTIVE

Most anti-angiogenic preeclampsia models in rodents utilized the overexpression of a truncated soluble fms-like tyrosine kinase-1 (sFlt-1) not expressed in any species. Other limitations of mouse preeclampsia models included stressful blood pressure measurements and the lack of postpartum monitoring. We aimed to 1) develop a mouse model of preeclampsia by administering the most abundant human placental sFlt-1 isoform (hsFlt-1-e15a) in preeclampsia; 2) determine blood pressures in non-stressed conditions; and 3) develop a survival surgery that enables the collection of fetuses and placentas and postpartum (PP) monitoring.

METHODS

Pregnancy status of CD-1 mice was evaluated with high-frequency ultrasound on gestational days (GD) 6 and 7. Telemetry catheters were implanted in the carotid artery on GD7, and their positions were verified by ultrasound on GD13. Mice were injected through tail-vein with adenoviruses expressing hsFlt-1-e15a (n = 11) or green fluorescent protein (GFP; n = 9) on GD8/GD11. Placentas and pups were delivered by cesarean section on GD18 allowing PP monitoring. Urine samples were collected with cystocentesis on GD6/GD7, GD13, GD18, and PPD8, and albumin/creatinine ratios were determined. GFP and hsFlt-1-e15a expression profiles were determined by qRT-PCR. Aortic ring assays were performed to assess the effect of hsFlt-1-e15a on endothelia.

RESULTS

Ultrasound predicted pregnancy on GD7 in 97% of cases. Cesarean section survival rate was 100%. Mean arterial blood pressure was higher in hsFlt-1-e15a-treated than in GFP-treated mice (∆MAP = 13.2 mmHg, p = 0.00107; GD18). Focal glomerular changes were found in hsFlt-1-e15a -treated mice, which had higher urine albumin/creatinine ratios than controls (109.3 ± 51.7 μg/mg vs. 19.3 ± 5.6 μg/mg, p = 4.4 x 10(-2); GD18). Aortic ring assays showed a 46% lesser microvessel outgrowth in hsFlt-1-e15a-treated than in GFP-treated mice (p = 1.2 x 10(-2)). Placental and fetal weights did not differ between the groups. One mouse with liver disease developed early-onset preeclampsia-like symptoms with intrauterine growth restriction (IUGR).

CONCLUSIONS

A mouse model of late-onset preeclampsia was developed with the overexpression of hsFlt-1-e15a, verifying the in vivo pathologic effects of this primate-specific, predominant placental sFlt-1 isoform. HsFlt-1-e15a induced early-onset preeclampsia-like symptoms associated with IUGR in a mouse with a liver disease. Our findings support that hsFlt-1-e15a is central to the terminal pathway of preeclampsia, and it can induce the full spectrum of symptoms in this obstetrical syndrome.

First trimester placental retinol-binding protein 4 (RBP4) and pregnancy-associated placental protein A (PAPP-A) in the prediction of early-onset severe pre-eclampsia

OBJECTIVE

In a retrospective case-control study, we examined the levels of placental retinol-binding protein 4 (RBP4) and pregnancy-associated placental protein A (PAPP-A) in first-trimester maternal serum samples as well as maternal characteristics to predict early-onset and severe pre-eclampsia.

METHODS

In this retrospective case-control study, we identified females who delivered a singleton pregnancy on or after 24 weeks' gestation from 2003 to 2010 at Oulu University Hospital and had a retrospective first trimester trisomy screening, including serum PAPP-A measurement. Within this cohort, we identified 65 females who experienced early onset pre-eclampsia (EO-PE) and 742 controls who had uncomplicated deliveries. Retrospectively, we thawed all previously collected serum samples to measure placental retinol binding protein 4 (RBP4). PAPP-A and RBP4 were measured using automatic immunoassay systems and converted to multiples of the median (MoMs). Logistic regression analysis was performed to determine whether these biomarkers separately and in combination with maternal characteristics (maternal age, weight and smoking status) can be used to predict the development of early onset pre-eclampsia.

RESULTS

The expected log(10) PAPP-A concentration and the expected log(10) RBP4 concentration in the control group were both affected by maternal weight and smoking status. The expected log(10) PAPP-A concentration was also affected by gestational age (GA). RBP4 levels in first-trimester serum were significantly higher in females who subsequently developed EO-PE outcome compared to those with normal pregnancy outcome (1.14 vs. 1.01 MoMs, p<0.0001). Maternal serum PAPP-A levels from the same pregnancy period were significantly lower in the EO-PE group compared to controls (0.80 vs. 1.05 MoMs, p=0.005). The risk model including maternal characteristics with PAPP-A log(10) MoM and RBP4 log(10) MoM had the best EO-PE prediction ability. It detected 34% (23%-46%) of females with subsequent EO-PE with a 10% false positive rate.

CONCLUSION

This study showed that first-trimester maternal serum RBP4 was significantly increased and that PAPP-A decreased in pregnancies that ended in EO-PE compared to normal pregnancies. Thus, these markers may be useful members in a panel of markers for the early detection of early-onset and severe pre-eclampsia.

The effects of gene polymorphisms in angiotensin II receptors on pregnancy-induced hypertension and preeclampsia: a systematic review and meta-analysis

BACKGROUND

To assess whether the polymorphisms of angiotensin II type 1 and type 2 receptors (AT1R, AT2R) are associated with pregnancy-induced hypertension (PIH) and preeclampsia.

METHODS

Studies were searched from PubMed, ISI Web of Science and HuGE Navigator.

RESULTS

The A1166C polymorphism of AT1R, A1675G and C3123A polymorphisms of AT2R were analyzed. Significant association was found in recessive model (OR = 1.581, 95% confidence interval (CI): 1.054-2.371) and co-dominant (GG versus AG) model (OR = 1.900, 95%CI: 1.001-3.604) between the A1675G polymorphism and preeclampsia. No association was found between the other polymorphisms and PIH or preeclampsia.

CONCLUSIONS

The A1675G polymorphism might be associated with preeclampsia, but the A1166C and C3123A polymorphisms had no effect on PIH or preeclampsia.

Genome-scale hypomethylation in the cord blood DNAs associated with early onset preeclampsia

Background

Preeclampsia is one of the leading causes of fetal and maternal morbidity and mortality worldwide. Preterm babies of mothers with early onset preeclampsia (EOPE) are at higher risks for various diseases later on in life, including cardiovascular diseases. We hypothesized that genome-wide epigenetic alterations occur in cord blood DNAs in association with EOPE and conducted a case control study to compare the genome-scale methylome differences in cord blood DNAs between 12 EOPE-associated and 8 normal births.

Results

Bioinformatics analysis of methylation data from the Infinium HumanMethylation450 BeadChip shows a genome-scale hypomethylation pattern in EOPE, with 51,486 hypomethylated CpG sites and 12,563 hypermethylated sites (adjusted P <0.05). A similar trend also exists in the proximal promoters (TSS200) associated with protein-coding genes. Using summary statistics on the CpG sites in TSS200 regions, promoters of 643 and 389 genes are hypomethylated and hypermethylated, respectively. Promoter-based differential methylation (DM) analysis reveals that genes in the farnesoid X receptor and liver X receptor (FXR/LXR) pathway are enriched, indicating dysfunction of lipid metabolism in cord blood cells. Additional biological functional alterations involve inflammation, cell growth, and hematological system development. A two-way ANOVA analysis among coupled cord blood and amniotic membrane samples shows that a group of genes involved in inflammation, lipid metabolism, and proliferation are persistently differentially methylated in both tissues, including IL12B, FAS, PIK31, and IGF1.

Conclusions

These findings provide, for the first time, evidence of prominent genome-scale DNA methylation modifications in cord blood DNAs associated with EOPE. They may suggest a connection between inflammation and lipid dysregulation in EOPE-associated newborns and a higher risk of cardiovascular diseases later in adulthood.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0052-x) contains supplementary material, which is available to authorized users.

Association between preeclampsia and the CXC chemokine family (Review)

Preeclampsia is a major cause of maternal and perinatal mortality and morbidity, characterized by gestational hypertension, proteinuria, systemic endothelial cell activation and an exaggerated inflammatory response. The precise cause of preeclampsia is not currently known; however, it is widely accepted that the pathogenesis of preeclampsia involves inadequate trophoblast invasion, leading to generalized endothelial dysfunction and an exaggerated inflammatory response. Chemokines are a superfamily of structurally similar proteins that mediate cell recruitment, angiogenesis, immunity and stem cell trafficking. CXC chemokines are a family of cytokines, unique in their ability to behave in a disparate manner in the regulation of angiogenesis. The CXC chemokine family further divides into two subfamilies; CXC ELR+, which promotes angiogenesis, and CXC ELR-, which inhibits angiogenesis. Furthermore, CXC chemokines are involved in the pathogenesis of various conditions, including malignant tumors, wound repair, chronic inflammation, atherosclerosis and potentially preeclampsia.

Nitric oxide dysregulation in the pathogenesis of preeclampsia among Ghanaian women

BACKGROUND

Preeclampsia (PE) is still a disease of theories as the exact cause remains uncertain. Widespread vascular endothelial cell dysfunction is thought to mediate the generalized vasospasm and hypertension characteristic of PE. Altered nitric oxide (NO) production has been associated with the endothelial dysfunction in the pathogenesis of PE but conflicting results have emerged from previous studies.

OBJECTIVES

To determine maternal serum levels of NO, a biomarker of endothelial function, in nonpregnant, normal pregnant, and preeclamptic women.

MATERIALS AND METHODS

This was a cross-sectional case-control study of 277 women comprising 75 nonpregnant, 102 normal pregnant, and 100 preeclamptic women conducted at the Korle Bu Teaching Hospital between April and June 2011. About 5 mL of venous blood was obtained from the participants for the various investigations after meeting the inclusion criteria and signing to a written consent. Serum levels of NO were determined by Griess reaction. The data obtained were analyzed with SPSS version 20.

RESULTS

The study showed significantly elevated serum levels of NO in preeclamptic women (82.45±50.31 μM) compared with normal pregnant (33.12±17.81 μM) and nonpregnant (16.92±11.41 μM) women with P<0.001. The alteration in maternal serum NO levels was significantly more profound in early-onset (severe) PE (119.63±45.860 μM) compared to that of late-onset (mild) disease (62.44±40.44 μM) with P<0.001, indicating a more severe vascular endothelial cell dysfunction in the early-onset disease.

CONCLUSION

This study has determined a profound NO upregulation in PE evidenced by significant elevation of NO metabolite levels compared to normal pregnancy. This might be due to deranged endothelial function with dysregulated production of NO to restore the persistent hypertension characteristic of PE.

New biomarkers in diagnosis of early onset preeclampsia and imminent delivery prognosis

BACKGROUND

Several studies have revealed a high soluble fms-like tyrosine kinase 1 (sFlt-1) to placental growth factor (PlGF) ratio in preeclamptic women. However, its role in patients with suspected preeclampsia (PE) at triage in the emergency department remains an issue and a controversial unique cutpoint of 85 has been proposed regardless of gestational age. A new cutpoint for sFlt-1/PlGF ratio was investigated to rule out PE at obstetric triage, and to assess its prognostic value for risk of imminent delivery.

METHODS

Blood samples from 257 pregnant women with suspected PE were obtained at obstetric triage admission. Serum PlGF and sFlt-1 were measured by an electrochemoluminiscence immunoassay (ECLIA) on the immunoanalyzer Cobas e601 (Roche Diagnostics) and the corresponding ratio was calculated. Final outcomes (mainly development of PE) were reviewed and time between clinical presentation and delivery was calculated.

RESULTS

The best ratio cutpoint to diagnose PE changed according to gestational age: 23 (92.0% sensitivity, 81.1% specificity) and 45 (83.7% sensitivity, 72.6% specificity) for women <34 and ≥ 34 weeks' gestation, respectively. Furthermore, sFlt-1/PlGF ratio inversely correlated with time elapsed between clinical presentation and delivery, and a cutpoint of 178 could predict complications such as imminent delivery or fetal/neonatal death with a sensitivity of 70.6% and a specificity of 97.8%.

CONCLUSIONS

The new cut-off values for the sFlt-1/PlGF ratio adjusted by the gestational age at clinical presentation can be used to rule out PE at obstetric triage and to predict imminent delivery with better accuracy than the cutpoint currently accepted.

Adjuvanted vaccines in pregnancy: no evidence for effect of the adjuvanted H1N1/09 vaccination on occurrence of preeclampsia or intra-uterine growth restriction

OBJECTIVE

During the H1N1/09 pandemic, pregnant women in the Netherlands were vaccinated with an adjuvanted vaccine. During pregnancy, the maternal immune system changes to enable placental development and growth and acceptance of the semi-allogeneic fetus. As an adjuvant is a pro-inflammatory substance, it may interfere with these immunological changes, resulting in poor placentation or placental growth, which may result in preeclampsia (PE) and fetal intra-uterine growth restriction (IUGR). This study investigated a possible association between adjuvanted H1N1/09 vaccination and the development of PE and/or IUGR.

STUDY DESIGN

Case-control study. Cases were Dutch women with PE and/or IUGR occurring during H1N1/09 vaccination program. Controls had uncomplicated pregnancies during the same period. Maternal characteristics, pregnancy and neonatal outcomes were collected from medical files. Participants were contacted by telephone to enquire about vaccination. Data were analyzed using t-tests, Chi-square tests or Fisher's exact tests. Multivariate analysis was conducted to control for confounders.

RESULTS

We included 254 cases and 247 controls. Of the cases, 90 (35.4%) were vaccinated, compared to 87 (35.2%) of the controls (OR:1.009, 95% CI:0.70-1.46, p:0.961). The majority (73.5%) had been vaccinated in second and third trimester. In multivariate analysis, there were no confounders influencing these results. Exploratory subgroup analysis did not show an association between vaccination status in subgroups of women with either PE or IUGR.

CONCLUSION

Our study showed no association between adjuvanted H1N1/09 vaccination and PE and/or IUGR.

Pulsatility index in combination with biomarkers or mean arterial pressure for the prediction of pre-eclampsia: Systematic literature review and meta-analysis

INTRODUCTION

Our objective was to perform a meta-analysis examining the sensitivity of pulsatility index (PI) and various biomarkers and PI and mean arterial pressure (MAP) for the prediction of pre-eclampsia.

MATERIAL AND METHODS

PubMed, CENTRAL, and Embase databases were searched from inception until 8 May 2014 using combinations of the search terms: pre-eclampsia, ultrasonography, pregnancy, biomarker, mean arterial pressure, placental protein 13, pregnancy-associated plasma protein-A, placental growth factor, activin A, inhibin A, pulsatility index. The pooled sensitivity of PI + biomarkers and PI + MAP were calculated, and reported with corresponding 95% confidence intervals (CIs).

RESULTS

Fifteen studies were included in the meta-analysis. The pooled sensitivity of all biomarkers for the prediction of pre-eclampsia was 0.669 (95% CI 0.610-0.723), for the prediction of early-onset pre-eclampsia was 0.830 (95% CI 0.794-0.861), and for the prediction of late-onset pre-eclampsia was 0.564 (95% CI 0.499-0.627). Similarly, the predictive ability of PI + MAP for early-onset pre-eclampsia was good (sensitivity 0.894), while that for late-onset was poor (sensitivity 0.570).

CONCLUSION

The combination of PI and different biomarkers or MAP exhibits a good predictive ability for early-onset pre-eclampsia, and poor predictive ability for late-onset pre-eclampsia.

Inconformity of CXCL3 plasma level and placenta expression in preeclampsia and its effect on trophoblast viability and invasion

As a member of the chemokine family, CXCL3 was previously known to participate in many pathophysiological events. However, whether CXCL3 stimulates trophoblast invasion as a key process of preeclampsia pathogenesis remains largely unknown. Therefore, the aim of this study was to investigate this hypothesis and determine the effect of CXCL3 on the first trimester trophoblast. Seventy gravidas were included in this study. ELISA was used to detect CXCL3 plasma levels on preeclampsia and normal pregnant groups. CXCL3 protein and mRNA levels were detected via Western blot and real-time quantitative PCR analysis after immunolocalized in human placenta. Moreover, the CXCL3 function in HTR-8/Svneo was analyzed via WST-1 assay, flow cytometry and invasion test. The plasma CXCL3 level in preeclampsia was significantly higher than that in normal pregnancy. CXCL3 expression was observed in the cytoplasm of placental trophoblasts and vascular endothelium in all groups without significant difference between maternal and fetal sides. In addition, placenta CXCL3 expression in severe preeclampsia was significantly lower than those in normal and mild PE groups. Moreover, exogenous CXCL3 can promote the proliferation and invasion of HTR-8/Svneo; however, its effect on apoptosis remains unclear. In summary, a significant abnormality of plasma CXCL3 level and placental CXCL3 expression was discovered in severe preeclampsia; CXCL3 had a function in trophoblast invasion, which indicated its participation in shallow implantation. Therefore CXCL3 might be involved in severe preeclampsia pathogenesis.