Plasma soluble vascular endothelial growth factor receptor-1 concentration is elevated prior to the clinical diagnosis of pre-eclampsia

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

OBJECTIVES

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Circulating soluble fms-like tyrosine kinase-1, soluble endoglin and placental growth factor during pregnancy in normotensive women in KwaZulu-Natal, South Africa

BACKGROUND

Based on the increased pre-eclampsia and HIV antenatal incidence in South Africa, we determined the angiogenic profiles due to its mechanistic link in preeclampsia development, throughout uncomplicated pregnancies in HIV positive and negative women.

OBJECTIVE

To determine the angiogenic profiles throughout uncomplicated pregnancies in HIV positive and HIV negative women. We explored possible correlations between angiogenic serum levels and selected maternal characteristics (HIV status, gestational age, maternal factors, and pregnancy outcomes).

METHOD

This study was conducted at a primary health care facility in Durban, South Africa. Forty-six pregnant women aged 18-45 years, were enrolled at 10-20, 22-30 and 32-38 weeks' gestation, respectively through convenient sampling. Serum samples were collected and quantitatively evaluated using ELISAs. Clinical and epidemiological data were analysed using STATA (version 14). A probability level of p < 0.05 was considered statistically significant.

RESULTS

Of those enrolled, 28.3% were nulliparous, 82% were HIV positive and none developed pre-eclampsia. Systolic and diastolic blood pressure increased slightly throughout pregnancy. Fluctuating angiogenic and anti-angiogenic levels were demonstrated during pregnancy.

CONCLUSION

This study contributes to the current angiogenic knowledge in normotensive pregnancies, and may assist as a reference range against which these factors may be compared in HIV complicated pregnancies.

The diagnostic conundrum of maternal mirror syndrome progressing to pre-eclampsia - A case report

Mirror syndrome, also called Ballantyne syndrome, is a rare condition in pregnancy, defined by the presence of the clinical triad of fetal hydrops, placentomegaly and maternal oedema. Any aetiology of fetal hydrops, including rhesus iso-immunization, congenital infection, twin-to-twin transfusion, structural anomalies and fetal malignancies, can lead to the syndrome. The pathogenesis, although not well established, mimics trophoblastic damage and maternal vascular endothelial dysfunction, as is also seen in pre-eclampsia, and, hence, the two conditions may have a similar clinical presentation. They may even co-exist, where a patient with maternal mirror syndrome develops features of pre-eclampsia. A timely, accurate diagnosis and prompt interventions are needed to prevent fetal mortality and maternal morbidity.

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Mirror syndrome is a rare condition in pregnancy defined by the clinical triad of fetal, placental and maternal hydrops

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The correction of fetal hydrops (and, hence placental hydrops) resolves Mirror syndrome

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The trophoblastic damage caused by placental oedema causes endothelial dysfunction leading to Mirror syndrome

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Although Mirror syndrome and pre-eclampsia have different aetiologies they may have similar presentations and co-exist

Pre-eclampsia: pathogenesis, novel diagnostics and therapies

Pre-eclampsia is a complication of pregnancy that is associated with substantial maternal and fetal morbidity and mortality. The disease presents with new-onset hypertension and often proteinuria in the mother, which can progress to multi-organ dysfunction, including hepatic, renal and cerebral disease, if the fetus and placenta are not delivered. Maternal endothelial dysfunction due to circulating factors of fetal origin from the placenta is a hallmark of pre-eclampsia. Risk factors for the disease include maternal comorbidities, such as chronic kidney disease, hypertension and obesity; a family history of pre-eclampsia, nulliparity or multiple pregnancies; and previous pre-eclampsia or intrauterine fetal growth restriction. In the past decade, the discovery and characterization of novel antiangiogenic pathways have been particularly impactful both in increasing understanding of the disease pathophysiology and in directing predictive and therapeutic efforts. In this Review, we discuss the pathogenic role of antiangiogenic proteins released by the placenta in the development of pre-eclampsia and review novel therapeutic strategies directed at restoring the angiogenic imbalance observed during pre-eclampsia. We also highlight other notable advances in the field, including the identification of long-term maternal and fetal risks conferred by pre-eclampsia.

Early onset preeclampsia in a model for human placental trophoblast

Preeclampsia, a leading cause of maternal and perinatal morbidity and mortality worldwide, is accompanied by shallow placentation and deficient remodeling of the uterine spiral arteries by invasive placental trophoblast cells during the first trimester of pregnancy. Here, we generated induced pluripotent stem cells from umbilical cords of normal pregnancies and ones complicated by early onset preeclampsia (EOPE) and converted them to trophoblast to recapitulate events of early pregnancy. Parameters disturbed in EOPE, including trophoblast invasiveness, were assessed. Under low O₂, both sets of cells behaved similarly, but, under the more stressful 20% O₂ conditions, the invasiveness of EOPE trophoblast was markedly reduced. Gene expression changes in EOPE trophoblast suggested a dysregulation invasion linked to high O₂.

We describe a model for early onset preeclampsia (EOPE) that uses induced pluripotent stem cells (iPSCs) generated from umbilical cords of EOPE and control (CTL) pregnancies. These iPSCs were then converted to placental trophoblast (TB) representative of early pregnancy. Marker gene analysis indicated that both sets of cells differentiated at comparable rates. The cells were tested for parameters disturbed in EOPE, including invasive potential. Under 5% O₂, CTL TB and EOPE TB lines did not differ, but, under hyperoxia (20% O₂), invasiveness of EOPE TB was reduced. RNA sequencing analysis disclosed no consistent differences in expression of individual genes between EOPE TB and CTL TB under 20% O₂, but, a weighted correlation network analysis revealed two gene modules (CTL4 and CTL9) that, in CTL TB, were significantly linked to extent of TB invasion. CTL9, which was positively correlated with 20% O₂ (P = 0.02) and negatively correlated with invasion (P = 0.03), was enriched for gene ontology terms relating to cell adhesion and migration, angiogenesis, preeclampsia, and stress. Two EOPE TB modules, EOPE1 and EOPE2, also correlated positively and negatively, respectively, with 20% O₂ conditions, but only weakly with invasion; they largely contained the same sets of genes present in modules CTL4 and CTL9. Our experiments suggest that, in EOPE, the initial step precipitating disease is a reduced capacity of placental TB to invade caused by a dysregulation of O₂ response mechanisms and that EOPE is a syndrome, in which unbalanced expression of various combinations of genes affecting TB invasion provoke disease onset.

Preeclampsia and HELLP syndrome, the role of the liver

Preeclampsia is a multisystemic disorder which accounts for the high prevalence of maternal and perinatal morbidity and mortality, especially in middle and low-income countries. Currently, the primary intervention is the urgent delivery of the fetus, hence it would be advantageous to identify those who are likely to develop preeclampsia and the maternal and fetal outcomes. However, an array of risk factors makes these challenging. This review explores the potentials of liver biomarkers in predicting the occurrence and outcome of preeclampsia, which could be beneficial in reducing the burden of the disease. Liver dysfunction in preeclampsia results in a severe condition, hence liver function tests are specific predictors of outcome.

Anti-angiogenic isoform of vascular endothelial growth factor-A in cardiovascular and renal disease

Accumulating evidence suggests that pathologic interactions between the heart and the kidney can contribute to the progressive dysfunction of both organs. Recently, there has been an increase in the prevalence of cardiovascular disease (CVD) and chronic kidney disease (CKD) due to increasing obesity rates. It has been reported that obesity causes various heart and renal disorders and appears to accelerate their progression. Vascular endothelial growth factor-A (VEGF-A) is a major regulator of angiogenesis and vessel permeability, and is associated with CVD and CKD. It is now recognized that alternative VEGF-A gene splicing generates VEGF-A isoforms that differ in their biological actions. Proximal splicing that includes an exon 8a sequence results in pro-angiogenic VEGF-A₁₆₅a, whereas distal splicing inclusive of exon 8b yields the anti-angiogenic isoform of VEGF-A (VEGF-A₁₆₅b). This review highlights several recent preclinical and clinical studies on the role of VEGF-A₁₆₅b in CVD and CKD as a novel function of VEGF-A. This review also discusses potential therapeutic approaches of the use of VEGF-A in clinical settings as a potential circulating biomarker for CVD and CKD.

Association of antepartum blood pressure levels and angiogenic profile among women with chronic hypertension

BACKGROUND

Angiogenic factors have been implicated in the pathogenesis of preeclampsia. This pilot study explored the association between antenatal blood pressure levels and angiogenic biomarkers (sFlt1 and PlGF) among women with chronic hypertension (cHTN).

METHODS

Blood samples were collected from women with cHTN (with/without superimposed preeclampsia) within 96 h prior to delivery. Subjects were stratified by mean outpatient BP as controlled (cBP < 140/90) or uncontrolled (uBP ≥ 140/90). Descriptive statistics were generated and assessed as appropriate. Logistic regression was employed to assess for adverse pregnancy outcomes between groups.

RESULTS

Data from seventy-eight women were analyzed, of which 58 (74.4%) were African American. Fifty-six (71.8%) had cBP and 22 (28.2%) had uBP. Use of antepartum outpatient antihypertensive medications was more frequent in patients with uBP (46.4% vs. 13.6%, p = 0.01). Compared to women with cBP, women with uBP had higher levels of pre-delivery sFlt1 and sFlt1/PlGF ratio (sFlt: 4218.5 vs. 3056.0 pg/ml, p = 0.046; sFlt/PlGF: 62.5 vs. 25.0, p = 0.04). Additionally, more uBP patients had superimposed preeclampsia with severe features (54.6% vs. 25.0%; p = 0.01) and preterm delivery (defined as a gestational age <35 weeks (40.9% vs. 10.7%; p = 0.002)) than cBP patients. In the multivariable model, women with uBP had greater odds of preterm delivery (OR 6.78; p = 0.01), superimposed preeclampsia (OR 3.20; p = 0.03) and preeclampsia with severe features (OR 3.27; p = 0.04) than women with cBP.

CONCLUSION

In women with cHTN, elevated antepartum BP is associated with worsened outcomes and may be associated with abnormal angiogenic profile at delivery. Larger studies are needed to confirm these findings.

Upregulation of Nrf2 and Decreased Redox Signaling Contribute to Renoprotective Effects of Chemerin Receptor Blockade in Diabetic Mice

Chemerin, acting through its receptor ChemR23, is an adipokine associated with inflammatory response, glucose and lipid metabolism and vascular function. Although this adipokine has been associated with the development and progression of kidney disease, it is not clear whether the chemerin/ChemR23 system plays a role in renal function in the context of diabetes. Therefore, we sought to determine whether ChemR23 receptor blockade prevents the development and/or progression of diabetic nephropathy and questioned the role of oxidative stress and Nrf2 in this process. Renal redox state and function were assessed in non-diabetic lean db/m and diabetic obese db/db mice treated with vehicle or CCX832 (ChemR23 antagonist). Renal reactive oxygen species (ROS) production, which was increased in diabetic mice, was attenuated by CCX832. This was associated with an increase in Nox 4 expression. Augmented protein oxidation in db/db mice was not observed when mice were treated with CCX832. CCX832 also abrogated impaired Nrf2 nuclear activity and associated downregulation in antioxidants expression in kidneys from db/db mice. Our in vivo findings highlight the role of the redox signaling and Nrf2 system as renoprotective players during chemerin receptor blockade in diabetic mice. The chemerin/ChemR23 system may be an important target to limit renal dysfunction associated with obesity-related diabetes.

Integrated Systems Biology Approach Identifies Novel Maternal and Placental Pathways of Preeclampsia

Preeclampsia is a disease of the mother, fetus, and placenta, and the gaps in our understanding of the complex interactions among their respective disease pathways preclude successful treatment and prevention. The placenta has a key role in the pathogenesis of the terminal pathway characterized by exaggerated maternal systemic inflammation, generalized endothelial damage, hypertension, and proteinuria. This sine qua non of preeclampsia may be triggered by distinct underlying mechanisms that occur at early stages of pregnancy and induce different phenotypes. To gain insights into these molecular pathways, we employed a systems biology approach and integrated different "omics," clinical, placental, and functional data from patients with distinct phenotypes of preeclampsia. First trimester maternal blood proteomics uncovered an altered abundance of proteins of the renin-angiotensin and immune systems, complement, and coagulation cascades in patients with term or preterm preeclampsia. Moreover, first trimester maternal blood from preterm preeclamptic patients in vitro dysregulated trophoblastic gene expression. Placental transcriptomics of women with preterm preeclampsia identified distinct gene modules associated with maternal or fetal disease. Placental "virtual" liquid biopsy showed that the dysregulation of these disease gene modules originates during the first trimester. In vitro experiments on hub transcription factors of these gene modules demonstrated that DNA hypermethylation in the regulatory region of ZNF554 leads to gene down-regulation and impaired trophoblast invasion, while BCL6 and ARNT2 up-regulation sensitizes the trophoblast to ischemia, hallmarks of preterm preeclampsia. In summary, our data suggest that there are distinct maternal and placental disease pathways, and their interaction influences the clinical presentation of preeclampsia. The activation of maternal disease pathways can be detected in all phenotypes of preeclampsia earlier and upstream of placental dysfunction, not only downstream as described before, and distinct placental disease pathways are superimposed on these maternal pathways. This is a paradigm shift, which, in agreement with epidemiological studies, warrants for the central pathologic role of preexisting maternal diseases or perturbed maternal-fetal-placental immune interactions in preeclampsia. The description of these novel pathways in the "molecular phase" of preeclampsia and the identification of their hub molecules may enable timely molecular characterization of patients with distinct preeclampsia phenotypes.

ELABELA plasma concentrations are increased in women with late-onset preeclampsia

Objective: ELABELA is a newly discovered peptide hormone that appears to be implicated in the mechanisms leading to preeclampsia, independently of angiogenic factors. The aim of the current study was to investigate whether women with early- or late-onset preeclampsia have altered ELABELA plasma concentrations compared to gestational-age-matched normal pregnant women.Methods: This retrospective cross-sectional study focused on the maternal plasma samples collected from 232 women with a singleton pregnancy who were allocated into the following groups: (1) early-onset preeclampsia (<34 weeks of gestation, N = 56); (2) late-onset preeclampsia (≥34 weeks of gestation, N = 57); and (3) gestational-age-matched controls with a normal pregnancy [(<34 weeks of gestation, N = 59); (≥34 weeks of gestation, N = 60)]. ELABELA plasma concentrations were determined using a validated enzyme immunoassay.Results: (1) ELABELA plasma concentrations are higher in patients with late-onset preeclampsia compared with those from gestational-age-matched controls with a normal pregnancy [median: 7.99 ng/mL (IQR, 5.3-13.95 ng/mL) versus median: 4.17 ng/mL (IQR, 3-11.19 ng/mL), p =.001]; (2) ELABELA plasma concentrations in patients with early-onset preeclampsia do not differ from those of normal pregnant women [median: 6.09 ng/mL (IQR, 2.8-10.66 ng/mL) versus median: 4.02 ng/mL (IQR, 3.26-7.49), p = .32]; and (3) ELABELA plasma concentrations are higher in patients with late-onset preeclampsia compared to those with early-onset preeclampsia [median: 7.99 ng/mL (IQR, 5.3-13.95 ng/mL) versus median: 6.09 ng/mL (IQR, 2.8-10.66 ng/mL), p = .01].Conclusion: ELABELA plasma concentrations are higher in patients with late-onset preeclampsia than in those with a normal pregnancy. However, women with early-onset preeclampsia have similar ELABELA plasma concentrations to those with a normal pregnancy. These findings provide insight into the ELABELA axis during the human syndrome of preeclampsia. In addition, these data support the concept that different pathophysiologic mechanisms are implicated in early- and late-onset preeclampsia.

Disruption in the Regulation of Immune Responses in the Placental Subtype of Preeclampsia

Preeclampsia is a pregnancy-specific disorder, of which one of its major subtypes, the placental subtype is considered a response to an ischemic placental environment, impacting fetal growth and pregnancy outcome. Inflammatory immune responses have been linked to metabolic and inflammatory disorders as well as reproductive failures. In healthy pregnancy, immune regulatory mechanisms prevent excessive systemic inflammation. However, in preeclampsia, the regulation of immune responses is disrupted as a result of aberrant activation of innate immune cells and imbalanced differentiation of T-helper cell subsets creating a cytotoxic environment in utero. Recognition events that facilitate immune interaction between maternal decidual T cells, NK cells, and cytotrophoblasts are considered an indirect cause of the incomplete remodeling of spiral arteries in preeclampsia. The mechanisms involved include the activation of immune cells and the subsequent secretion of cytokines and placental growth factors affecting trophoblast invasion, angiogenesis, and eventually placentation. In this review, we focus on the role of excessive systemic inflammation as the result of a dysregulated immune system in the development of preeclampsia. These include insufficient control of inflammation, failure of tolerance toward paternal antigens at the fetal-maternal interface, and subsequent over- or insufficient activation of immune mediators. It is also possible that external stimuli, such as bacterial endotoxin, may contribute to the excessive systemic inflammation in preeclampsia by stimulating the release of pro-inflammatory cytokines. In conclusion, a disrupted immune system might be a predisposing factor or result of placental oxidative stress or excessive inflammation in preeclampsia. Preeclampsia can thus be considered a hyperinflammatory state associated with defective regulation of the immune system proposed as a key element in the pathological events of the placental subtype of this disorder.

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

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

Cerebrospinal Fluid Protein Changes in Preeclampsia

The molecular mechanisms underlying seizure susceptibility in preeclampsia are unknown. We hypothesized that altered expression of distinct proteins in the cerebrospinal fluid (CSF) may reflect pathophysiological changes in the central nervous system that contribute to the neurological manifestations of severe preeclampsia. We obtained CSF samples from 13 patients with preeclampsia and 14 control patients during spinal anesthesia before delivery and analyzed them by SOMAscan, an aptamer-based proteomics platform for alterations in 1310 protein levels. Ingenuity Pathway Analysis was conducted to highlight relationships between preeclampsia-specific proteins found to be significantly altered. For 2 of the target proteins, we validated the difference in CSF concentrations by ELISA. SOMAscan revealed 82 proteins, whose expression levels were significantly different (P<0.05) in CSF from patients with preeclampsia versus controls. Principal component analysis achieved perfect separation of the preeclampsia and control groups in 2 dimensions. The differentially expressed proteins converge around 4 signaling molecules: TGF-β (transforming growth factor-β), VEGFA (vascular endothelial growth factor A), angiotensinogen, and IL-6 (interleukin-6). Within the TGF-β pathway, upregulation of activin A (301.6±47.4 versus 151.6±20.5 pg/mL; P=0.0074) and follistatin-related gene (5129±347 versus 3016±188 pg/mL; P<0.0001) in preeclampsia was confirmed by ELISA. In summary, signaling pathways important for vascular remodeling, inflammation, and neuronal growth, signaling, and electrophysiology were well represented among the proteins found to be altered in CSF in patients with preeclampsia.

Angiogenic biomarkers in triage and risk for preeclampsia with severe features

There is an urgent need for biomarkers that can help stratify women with suspected preeclampsia (PE) for the subsequent appearance of PE with severe features (sPE), to improve risk assessment and direct monitoring related to complications of sPE. Elevated levels of circulating anti-angiogenic factors like soluble fms-like tyrosine kinase 1 (sFlt1) and decreased free levels of pro-angiogenic factors such as placental growth factor (PlGF) are associated with adverse outcomes related to preeclampsia (PE). Here, we report in a single-center prospective study (N = 402) that plasma levels of these circulating angiogenic markers predict sPE within two weeks among women presenting with suspected PE in the preterm period (<37 weeks). sFlt1/PlGF ratio of >38 at the triage visit had a positive predictive value (PPV) of 47% and a negative predictive value (NPV) of 98% for the presence of sPE within 2 weeks. Among patients presenting <34 weeks, the PPV for sPE improved to 65% with NPV of 98%. sFlt1/PlGF ratio >85, had a PPV of 59% in all patients and 74% among patients presenting <34 weeks for the presence of sPE within 2 weeks. When we restricted the analysis to hospitalized patients, PPVs were 58% and 63% in all patients and 73% and 77% for patients presenting <34 weeks for plasma sFlt1/PlGF cutoff >38 and >85 respectively. Clinical trials are needed to evaluate whether risk stratification with angiogenic biomarkers in patients with suspected PE will lead to improved maternal and fetal outcomes among women at risk for severe disease.

Long term follow up of biomarkers of podocyte damage and renal function in patients with and without preeclampsia

Introduction:

preeclampsia can be associated with future renal disease.

Objectives:

To measure changes in renal function overtime in patients with preeclampsia.

Methods:

urine and serum samples from eleven patients with preeclampsia and eight patients with a normal pregnancy were obtained during pregnancy, postpartum, and 3 years after delivery. Urine podocalyxin, protein, and serum creatinine were measured.

Results:

after 3 years, there were no significant differences in urinary podocalyxin in patients with or without preeclampsia: 4.34 ng/mg [2.69, 8.99] vs. 7.66 ng/mg [2.35, 13], p = 0.77. The same applied to urinary protein excretion: 81.5 mg/g [60.6, 105.5] vs. 43.2 mg/g [20.9, 139.3] p = 0.23. Serum creatinine was 0.86 mg/dL [0.7, 0.9] vs. 0.8 mg/dL [0.68, 1] p = 0.74 in those with and without preeclampsia. In normal patients, urinary podocalyxin decreased from 54.4 ng/mg [34.2, 76.9] during pregnancy to 7.66 ng/mg [2.35, 13] three years after pregnancy, p = 0.01. Proteinuria decreased from 123.5 mg/g [65.9, 194.8] to 43.2 mg/g [20.9, 139.3], p = 0.12. In preeclampsia patients, urinary podocalyxin decreased from 97.5 ng/mg [64.9, 318.4] during pregnancy to 37.1 ng/mg within one week post-partum [21.3, 100.4] p = 0.05 and 4.34 ng/mg [2.69, 8.99] three years after, p = 0.003. Proteinuria was 757.2 mg/g [268.4, 5031.7] during pregnancy vs. 757.2 mg/g [288.2, 2917] postpartum, p = 0.09 vs. 81.5 mg/g [60.6, 105.5] three years later, p = 0.01. Two patients still had proteinuria after 3 years.

Conclusions:

in preeclampsia patients, postpartum urinary podocalyxin decreased before proteinuria. After three years, serum creatinine, urinary podocalyxin, and protein tended to normalize, although some patients still had proteinuria.

Preeclampsia: Pathogenesis, Prevention, and Long-Term Complications

Preeclampsia continues to afflict 5% to 8% of all pregnancies throughout the world and is associated with significant morbidity and mortality to the mother and the fetus. Although the pathogenesis of the disorder has not yet been fully elucidated, current evidence suggests that imbalance in angiogenic factors is responsible for the clinical manifestations of the disorder, and may explain why certain populations are risk. In this review, we begin by demonstrating the roles that angiogenic factors play in pathogenesis of preeclampsia and its complications in the mother and the fetus. We then continue to report on the use of angiogenic markers as biomarkers to predict and risk-stratify disease. Strategies to treat preeclampsia by correcting the angiogenic balance, either by promoting proangiogenic factors or by removing antiangiogenic factors in both animal and human studies, are discussed. We end the review by summarizing status of the current preventive strategies and the long-term cardiovascular outcomes of women afflicted with preeclampsia.

Early Detection of Preeclampsia Using Circulating Small non-coding RNA

Preeclampsia is one of the most dangerous pregnancy complications, and the leading cause of maternal and perinatal mortality and morbidity. Although the clinical symptoms appear late, its origin is early, and hence detection is feasible already at the first trimester. In the current study, we investigated the abundance of circulating small non-coding RNAs in the plasma of pregnant women in their first trimester, seeking transcripts that best separate the preeclampsia samples from those of healthy pregnant women. To this end, we performed small non-coding RNAs sequencing of 75 preeclampsia and control samples, and identified 25 transcripts that were differentially expressed between preeclampsia and the control groups. Furthermore, we utilized those transcripts and created a pipeline for a supervised classification of preeclampsia. Our pipeline generates a logistic regression model using a 5-fold cross validation on numerous random partitions into training and blind test sets. Using this classification procedure, we achieved an average AUC value of 0.86. These findings suggest the predictive value of circulating small non-coding RNA in the first trimester, warranting further examination, and lay the foundation for producing a novel early non-invasive diagnostic tool for preeclampsia, which could reduce the life-threatening risk for both the mother and fetus.

The profiles of soluble adhesion molecules in the "great obstetrical syndromes". J Matern Fetal Neonatal Med 2018;32:2113-2136. [PMID: 29320948 DOI: 10.1080/14767058.2018.1427058]

OBJECTIVE

The objective of this study was to determine the profiles of maternal plasma soluble adhesion molecules in patients with preeclampsia, small-for-gestational-age (SGA) fetuses, acute pyelonephritis, preterm labor with intact membranes (PTL), preterm prelabor rupture of the membranes (preterm PROM), and fetal death.

MATERIALS AND METHODS

A cross-sectional study was conducted to determine maternal plasma concentrations of sE-selectin, sL-selectin, and sP-selectin as well as sICAM-1, sVCAM-1, and sPECAM-1 in patients with (1) an uncomplicated pregnancy (control, n = 100); (2) preeclampsia (n = 94); (3) SGA fetuses (in women without preeclampsia/hypertension, n = 45); (4) acute pyelonephritis (n = 25); (5) PTL (n = 53); (6) preterm PROM (n = 24); and (7) fetal death (n = 34). Concentrations of soluble adhesion molecules and inflammatory cytokines (tumor necrosis factor (TNF)-α and interleukin (IL)-8) were determined with sensitive and specific enzyme-linked immunoassays.

RESULTS

In comparison to women with a normal pregnancy, (1) women with preeclampsia had higher median concentrations of sE-selectin, sP-selectin, and sVCAM-1, and a lower concentration of sL-selectin (all p values < .001); (2) patients with SGA fetuses had higher median concentrations of sE-selectin, sP-selectin, and sVCAM-1 (all p values < .05); (3) patients with a fetal death had higher median concentrations of sE-selectin and sP-selectin (all p values < .05); (4) patients with acute pyelonephritis had higher median plasma concentrations of sE-selectin, sICAM-1, and sVCAM-1 (all p values < .001); (5) patients with preeclampsia and acute pyelonephritis, plasma concentrations of sVCAM-1, sE-selectin, and sP-selectin correlated with those of the proinflammatory cytokines TNF-α and interleukin (IL)-8 (all p values < .05); (6) patients with PTL had a higher median concentration of sP-selectin and a lower median concentration of VCAM-1 (all p values < .05); and (7) women with preterm PROM had lower median concentrations of sL-selectin and sVCAM-1 (all p values < .05).

CONCLUSIONS

The results of this study show that endothelial cell activation/dysfunction reflected by the plasma concentration of sE-selectin is not specific to preeclampsia but is present in pregnancies complicated by SGA fetuses, acute pyelonephritis, and fetal death. Collectively, we report that each obstetrical syndrome appears to have a stereotypical profile of soluble adhesion molecules in the peripheral circulation.

The prediction of fetal death with a simple maternal blood test at 20-24 weeks: a role for angiogenic index-1 (PlGF/sVEGFR-1 ratio)

BACKGROUND

Fetal death is an obstetrical syndrome that annually affects 2.4 to 3 million pregnancies worldwide, including more than 20,000 in the United States each year. Currently, there is no test available to identify patients at risk for this pregnancy complication.

OBJECTIVE

We sought to determine if maternal plasma concentrations of angiogenic and antiangiogenic factors measured at 24-28 weeks of gestation can predict subsequent fetal death.

STUDY DESIGN

A case-cohort study was designed to include 1000 randomly selected subjects and all remaining fetal deaths (cases) from a cohort of 4006 women with a singleton pregnancy, enrolled at 6-22 weeks of gestation, in a pregnancy biomarker cohort study. The placentas of all fetal deaths were histologically examined by pathologists who used a standardized protocol and were blinded to patient outcomes. Placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor-1 concentrations were measured by enzyme-linked immunosorbent assays. Quantiles of the analyte concentrations (or concentration ratios) were estimated as a function of gestational age among women who delivered a live neonate but did not develop preeclampsia or deliver a small-for-gestational-age newborn. A positive test was defined as analyte concentrations (or ratios) <2.5th and 10th centiles (placental growth factor, placental growth factor/soluble vascular endothelial growth factor receptor-1 [angiogenic index-1] and placental growth factor/soluble endoglin) or >90th and 97.5th centiles (soluble vascular endothelial growth factor receptor-1 and soluble endoglin). Inverse probability weighting was used to reflect the parent cohort when estimating the relative risk.

RESULTS

There were 11 fetal deaths and 829 controls with samples available for analysis between 24-28 weeks of gestation. Three fetal deaths occurred <28 weeks and 8 occurred ≥28 weeks of gestation. The rate of placental lesions consistent with maternal vascular underperfusion was 33.3% (1/3) among those who had a fetal death <28 weeks and 87.5% (7/8) of those who had this complication ≥28 weeks of gestation. The maternal plasma angiogenic index-1 value was <10th centile in 63.6% (7/11) of the fetal death group and in 11.1% (92/829) of the controls. The angiogenic index-1 value was <2.5th centile in 54.5% (6/11) of the fetal death group and in 3.7% (31/829) of the controls. An angiogenic index-1 value <2.5th centile had the largest positive likelihood ratio for predicting fetal death >24 weeks (14.6; 95% confidence interval, 7.7-27.7) and a relative risk of 29.1 (95% confidence interval, 8.8-97.1), followed by soluble endoglin >97.5th centile and placental growth factor/soluble endoglin <2.5th, both with a positive likelihood ratio of 13.7 (95% confidence interval, 7.3-25.8) and a relative risk of 27.4 (95% confidence interval, 8.2-91.2). Among women without a fetal death whose plasma angiogenic index-1 concentration ratio was <2.5th centile, 61% (19/31) developed preeclampsia or delivered a small-for-gestational-age neonate; when the 10th centile was used as the cut-off, 37% (34/92) of women had these adverse outcomes.

CONCLUSION

(1) A maternal plasma angiogenic index-1 value <2.5th centile (0.126) at 24-28 weeks of gestation carries a 29-fold increase in the risk of subsequent fetal death and identifies 55% of subsequent fetal deaths with a false-positive rate of 3.5%; and (2) 61% of women who have a false-positive test result will subsequently experience adverse pregnancy outcomes.

Metformin, the aspirin of the 21st century: its role in gestational diabetes mellitus, prevention of preeclampsia and cancer, and the promotion of longevity

Metformin is everywhere. Originally introduced in clinical practice as an antidiabetic agent, its role as a therapeutic agent is expanding to include treatment of prediabetes mellitus, gestational diabetes mellitus, and polycystic ovarian disease; more recently, experimental studies and observations in randomized clinical trials suggest that metformin could have a place in the treatment or prevention of preeclampsia. This article provides a brief overview of the history of metformin in the treatment of diabetes mellitus and reviews the results of metaanalyses of metformin in gestational diabetes mellitus as well as the treatment of obese, non-diabetic, pregnant women to prevent macrosomia. We highlight the results of a randomized clinical trial in which metformin administration in early pregnancy did not reduce the frequency of large-for-gestational-age infants (the primary endpoint) but did decrease the frequency of preeclampsia (a secondary endpoint). The mechanisms by which metformin may prevent preeclampsia include a reduction in the production of antiangiogenic factors (soluble vascular endothelial growth factor receptor-1 and soluble endoglin) and the improvement of endothelial dysfunction, probably through an effect on the mitochondria. Another potential mechanism whereby metformin may play a role in the prevention of preeclampsia is its ability to modify cellular homeostasis and energy disposition, mediated by rapamycin, a mechanistic target. Metformin has a molecular weight of 129 Daltons and therefore readily crosses the placenta. There is considerable evidence to suggest that this agent is safe during pregnancy. New literature on the role of metformin as a chemotherapeutic adjuvant in the prevention of cancer and in prolonging life and protecting against aging is reviewed briefly. Herein, we discuss the mechanisms of action and potential benefits of metformin.

Combination of copeptin, placental growth factor and total annexin V microparticles for prediction of preeclampsia at 10-14 weeks of gestation

INTRODUCTION

Preeclampsia (PE) remains to be an enigmatic puzzle for clinicians and researchers perplexing them for decades. As delivery remains only choice of treatment, early prediction of PE will offer timely therapeutic invention and hence extensive research efforts have been put in identification of biomarkers which will facilitate early prediction of PE.

METHODS

Serum levels of CPP, PlGF and plasma total annexin V MPs were assessed in women who subsequently developed PE (n = 33), IUGR (n = 81) and normal pregnancy outcome (n = 112) at 10-14 weeks of gestation. Comparison of biomarker levels between patients and control group was done using Mann Whitney test. Receiver operating curve (ROC) analysis and binary logistic regression analysis were used to evaluate predictive utility of combination of CPP, PlGF and total annexin V MPs for prediction of PE.

RESULTS

Women who subsequently developed PE showed significantly elevated levels of total annexin V MPs [2766.04 (2086.88-3794) versus 1090.74 (631.91-2197.16)] and CPP [440.98 (365.12-488.92) versus 217.8 (171.13-308.98)] compared to controls. Serum PlGF levels were significantly reduced in women with PE 17.68 (12.66-22.32) compared to controls 105.22 (35.02-255.1). Using logistic regression analysis, the combination of CPP, PlGF and total annexin V MPs gave high predictive value with AUC of 0.970, 93.1% sensitivity, 90.7% specificity, 77.50% Positive predictive value, 98.10% Negative predictive value, 11.69 Positive likelihood ratio and 0.07 Negative likelihood ratio for PE prediction at 10-14 weeks.

CONCLUSION

The combination of serum markers and plasma microparticles can be used for 10-14 weeks prediction and discrimination of PE from other pregnancy complications.

Impact of Preeclampsia on Clinical and Functional Outcomes in Women With Peripartum Cardiomyopathy

BACKGROUND

Preeclampsia is a risk factor for the development of peripartum cardiomyopathy (PPCM), but it is unknown whether preeclampsia impacts clinical or left ventricular (LV) functional outcomes. This study sought to assess clinical and functional outcomes in women with PPCM complicated by preeclampsia.

METHODS AND RESULTS

This retrospective cohort study included women diagnosed with PPCM delivering at Barnes-Jewish Hospital between 2004 to 2014. The primary outcome was one-year event-free survival rate for the combined end point of death and hospital readmission. The secondary outcome was recovery of LV ejection fraction. Seventeen of 39 women (44%) with PPCM had preeclampsia. The groups had similar mean LV ejection fraction at diagnosis (29.6 with versus 27.3 without preeclampsia; P=0.5). Women with preeclampsia had smaller mean LV end-diastolic diameters (5.2 versus 6.0 cm; P=0.001), greater relative wall thickness (0.41 versus 0.35 mm Hg; P=0.009), and lower incidence of eccentric remodeling (12% versus 48%; P=0.03). Clinical follow-up was available for 32 women; 5 died of cardiovascular complications within 1 year of diagnosis (4/15 with versus 1/17 without preeclampsia; P=0.16). In time to event analysis, patients with preeclampsia had worse event-free survival during 1-year follow-up (P=0.047). Echocardiographic follow-up was available in 10 survivors with and 16 without preeclampsia. LV ejection fraction recovered in 80% of survivors with versus 25% without preeclampsia (P=0.014).

CONCLUSIONS

PPCM with concomitant preeclampsia is associated with increased morbidity and mortality and different patterns of LV remodeling and recovery of LV function when compared with patients with PPCM that is not complicated by preeclampsia.

Human placental growth hormone in normal and abnormal fetal growth

Human placental growth hormone (PGH), encoded by the growth hormone (GH) variant gene on chromosome 17, is expressed in the syncytiotrophoblast and extravillous cytotrophoblast layers of the human placenta. Its maternal serum levels increase throughout pregnancy, and gradually replaces the pulsatile secreted pituitary GH. PGH is also detectable in cord blood and in the amniotic fluid. This placental-origin hormone stimulates glyconeogenesis, lipolysis and anabolism in maternal organs, and influences fetal growth, placental development and maternal adaptation to pregnancy. The majority of these actions are performed indirectly by regulating maternal insulin-like growth factor-I levels, while the extravillous trophoblast involvement indicates a direct effect on placental development, as it stimulates trophoblast invasiveness and function via a potential combination of autocrine and paracrine mechanisms. The current review focuses on the role of PGH in fetal growth. In addition, the association of PGH alterations in maternal circulation and placental expression in pregnancy complications associated with abnormal fetal growth is briefly reviewed.

The prediction of late-onset preeclampsia: Results from a longitudinal proteomics study

BACKGROUND

Late-onset preeclampsia is the most prevalent phenotype of this syndrome; nevertheless, only a few biomarkers for its early diagnosis have been reported. We sought to correct this deficiency using a high through-put proteomic platform.

METHODS

A case-control longitudinal study was conducted, including 90 patients with normal pregnancies and 76 patients with late-onset preeclampsia (diagnosed at ≥34 weeks of gestation). Maternal plasma samples were collected throughout gestation (normal pregnancy: 2-6 samples per patient, median of 2; late-onset preeclampsia: 2-6, median of 5). The abundance of 1,125 proteins was measured using an aptamers-based proteomics technique. Protein abundance in normal pregnancies was modeled using linear mixed-effects models to estimate mean abundance as a function of gestational age. Data was then expressed as multiples of-the-mean (MoM) values in normal pregnancies. Multi-marker prediction models were built using data from one of five gestational age intervals (8-16, 16.1-22, 22.1-28, 28.1-32, 32.1-36 weeks of gestation). The predictive performance of the best combination of proteins was compared to placental growth factor (PIGF) using bootstrap.

RESULTS

1) At 8-16 weeks of gestation, the best prediction model included only one protein, matrix metalloproteinase 7 (MMP-7), that had a sensitivity of 69% at a false positive rate (FPR) of 20% (AUC = 0.76); 2) at 16.1-22 weeks of gestation, MMP-7 was the single best predictor of late-onset preeclampsia with a sensitivity of 70% at a FPR of 20% (AUC = 0.82); 3) after 22 weeks of gestation, PlGF was the best predictor of late-onset preeclampsia, identifying 1/3 to 1/2 of the patients destined to develop this syndrome (FPR = 20%); 4) 36 proteins were associated with late-onset preeclampsia in at least one interval of gestation (after adjustment for covariates); 5) several biological processes, such as positive regulation of vascular endothelial growth factor receptor signaling pathway, were perturbed; and 6) from 22.1 weeks of gestation onward, the set of proteins most predictive of severe preeclampsia was different from the set most predictive of the mild form of this syndrome.

CONCLUSIONS

Elevated MMP-7 early in gestation (8-22 weeks) and low PlGF later in gestation (after 22 weeks) are the strongest predictors for the subsequent development of late-onset preeclampsia, suggesting that the optimal identification of patients at risk may involve a two-step diagnostic process.

The maternal plasma proteome changes as a function of gestational age in normal pregnancy: a longitudinal study

OBJECTIVE

Pregnancy is accompanied by dramatic physiological changes in maternal plasma proteins. Characterization of the maternal plasma proteome in normal pregnancy is an essential step for understanding changes to predict pregnancy outcome. The objective of this study was to describe maternal plasma proteins that change in abundance with advancing gestational age and determine biological processes that are perturbed in normal pregnancy.

STUDY DESIGN

A longitudinal study included 43 normal pregnancies that had a term delivery of an infant who was appropriate for gestational age without maternal or neonatal complications. For each pregnancy, 3 to 6 maternal plasma samples (median, 5) were profiled to measure the abundance of 1125 proteins using multiplex assays. Linear mixed-effects models with polynomial splines were used to model protein abundance as a function of gestational age, and the significance of the association was inferred via likelihood ratio tests. Proteins considered to be significantly changed were defined as having the following: (1) >1.5-fold change between 8 and 40 weeks of gestation; and (2) a false discovery rate-adjusted value of P < .1. Gene ontology enrichment analysis was used to identify biological processes overrepresented among the proteins that changed with advancing gestation.

RESULTS

The following results were found: (1) Ten percent (112 of 1125) of the profiled proteins changed in abundance as a function of gestational age; (2) of the 1125 proteins analyzed, glypican-3, sialic acid-binding immunoglobulin-type lectin-6, placental growth factor, C-C motif-28, carbonic anhydrase 6, prolactin, interleukin-1 receptor 4, dual-specificity mitogen-activated protein kinase 4, and pregnancy-associated plasma protein-A had more than a 5-fold change in abundance across gestation (these 9 proteins are known to be involved in a wide range of both physiological and pathological processes, such as growth regulation, embryogenesis, angiogenesis immunoregulation, inflammation etc); and (3) biological processes associated with protein changes in normal pregnancy included defense response, defense response to bacteria, proteolysis, and leukocyte migration (false discovery rate, 10%).

CONCLUSION

The plasma proteome of normal pregnancy demonstrates dramatic changes in both the magnitude of changes and the fraction of the proteins involved. Such information is important to understand the physiology of pregnancy and the development of biomarkers to differentiate normal vs abnormal pregnancy and determine the response to interventions.

Association Between Fetal Congenital Heart Defects and Maternal Risk of Hypertensive Disorders of Pregnancy in the Same Pregnancy and Across Pregnancies

BACKGROUND

Both pregnant women carrying fetuses with heart defects and women with hypertensive disorders of pregnancy often exhibit angiogenic imbalances, suggesting that the same mechanisms are involved in the pathogenesis of the former and the pathophysiology of the latter. We conducted a register-based cohort study to determine whether offspring congenital heart defects are associated with an increased risk of hypertensive disorders of pregnancy and whether the mechanisms driving any association are primarily maternal or fetal.

METHODS

Among singleton pregnancies without chromosomal abnormalities lasting ≥20 weeks in Denmark from 1978 to 2011 (n= 1 972 857), we identified pregnancies complicated by offspring congenital heart defects or early preterm preeclampsia, late preterm preeclampsia, term preeclampsia, and gestational hypertension. We used polytomous logistic regression to estimate odds ratios (ORs) for associations between offspring congenital heart defects and maternal hypertensive disorders of pregnancy overall and for specific heart defects.

RESULTS

Offspring congenital heart defects were strongly associated with early preterm preeclampsia (OR, 7.00; 95% confidence interval [CI], 6.11-8.03) and late preterm preeclampsia (OR, 2.82; 95% CI, 2.38-3.34) in the same pregnancy and weakly associated with term preeclampsia (OR, 1.16; 95% CI, 1.06-1.27), but they were not associated with gestational hypertension (OR, 1.07; 95% CI, 0.92-1.25). Association strengths were consistent across heart defect types. Offspring congenital heart defects in a previous pregnancy were also strongly associated with preterm preeclampsia in subsequent pregnancies (early preterm preeclampsia: OR, 2.37; 95% CI, 1.68-3.34; late preterm preeclampsia: OR, 2.04; 95% CI, 1.52-2.75) but were only modestly associated with term preeclampsia and not associated with gestational hypertension. Similarly, preterm preeclampsia in a previous pregnancy, but not term preeclampsia or gestational hypertension, was associated with offspring congenital heart defects in later pregnancies (early preterm preeclampsia: OR, 7.91; 95% CI, 6.06-10.3; late preterm preeclampsia: OR, 2.83; 95% CI, 2.11-3.79; term preeclampsia: OR, 0.98; 95% CI, 0.88-1.10; gestational hypertension: OR, 1.13; 95% CI, 0.92-1.38).

CONCLUSIONS

Linked pathophysiological mechanisms may be involved in some congenital heart defects and preterm preeclampsia. The strong associations across pregnancies support a predominantly maternal origin of effect.

Myocardial performance index in hypertensive disorders of pregnancy: The relationship between blood pressures and angiogenic factors

OBJECTIVE

To study the association between cardiac function measured by myocardial performance index (MPI), blood pressures and angiogenic factors measured at the time of echocardiography in patients with and without hypertensive disorders of pregnancy (HDP).

METHODS

We prospectively studied 189 pregnant women and evaluated whether changes in cardiac function observed on echocardiography were correlated with higher blood pressures and whether higher blood pressures were associated with antiangiogenic proteins (soluble fms-like tyrosine kinase, sFlt1; soluble endoglin, sEng). Comprehensive echocardiograms, including measurement of MPI, were performed on all patients. sFlt1 and sEng levels were measured using enzyme-linked immunosorbent assay.

RESULTS

Overall, 189 patients were divided into tertiles based on mean arterial pressure (MAP). The MPI was worst in tertile 3 (0.50 ± 0.15) compared to tertile 1 (0.42 ± 0.10), p = 0.0004. sFlt1 (pg/ml) and sEng (ng/ml) were highest in tertile 3 compared to tertile 1: 15055.37 vs. 1623.01 and 33.06 vs. 8.15, respectively, with p-value <0.001. In crude multivariate regression analysis, MAP was positively correlated with MPI (r = 0.32, p < 0.001), GLS (r = 0.54, p < 0.001), sFlt1 (r = 0.60, p < 0.001) and sEng (r = 0.61, p < 0.001). After adjustment for confounders, these relationships persisted between MAP and MPI (r = 0.31, p = 0.0003), GLS (r = 0.46, p < 0.001), sFlt1 (r = 0.56, p < 0.001) and sEng (r = 0.58, p < 0.001).

CONCLUSION

Mean arterial pressure correlates with worsening cardiac function as measured by MPI and serum levels of angiogenic factors. Further studies are needed to evaluate whether a reduction in blood pressure will reverse changes in MPI or reduce levels of angiogenic proteins seen among women with HDP.

Failure of physiologic transformation of spiral arteries, endothelial and trophoblast cell activation, and acute atherosis in the basal plate of the placenta

BACKGROUND

Failure of physiologic transformation of spiral arteries has been reported in preeclampsia, fetal growth restriction, fetal death, and spontaneous preterm labor with intact or ruptured membranes. Spiral arteries with failure of physiologic transformation are prone to develop atherosclerotic-like lesions of atherosis. There are striking parallels between preeclampsia and atherosclerotic disease, and between lesions of atherosis and atherosclerosis. Endothelial activation, identified by intercellular adhesion molecule-1 expression, is present in atherosclerotic-like lesions of heart transplantation, and is considered a manifestation of rejection. Similarly, endothelial activation/dysfunction has been implicated in the pathophysiology of atherosclerosis and preeclampsia. Intercellular adhesion molecule-1-overexpressing-activated endothelial cells are more resistant to trophoblast displacement than nonactivated endothelium, and may contribute to shallow spiral artery trophoblastic invasion in obstetrical syndromes having failure of physiologic transformation.

OBJECTIVE

We sought to determine whether failure of spiral artery physiologic transformation was associated with activation of interstitial extravillous trophoblasts and/or spiral artery endothelium and presence of acute atherosis in the placental basal plate.

STUDY DESIGN

A cross-sectional study of 123 placentas (19-42 weeks' gestation) obtained from normal pregnancies (n = 22), preterm prelabor rupture of membranes (n = 26), preterm labor (n = 23), preeclampsia (n = 27), intrauterine fetal death (n = 15), and small for gestational age (n = 10) was performed. Failure of spiral artery physiologic transformation and presence of cell activation was determined using immunohistochemistry of placental basal plates containing a median of 4 (minimum: 1; maximum: 9) vessels per placenta. Endothelial/trophoblast cell activation was defined by the expression of intercellular adhesion molecule-1. Investigators examining microscopic sections were blinded to clinical diagnosis. Pairwise comparisons among placenta groups were performed with Fisher exact test and Wilcoxon rank sum test using a Bonferroni-adjusted level of significance (.025).

RESULTS

We found that 87% (94/108) of placentas having spiral arteries with failure of physiologic transformation (actin-positive and cytokeratin-negative) in the basal plate, and 0% (0/15) of placentas having only spiral arteries with complete physiologic transformation (cytokeratin-positive and actin-negative), had arterial endothelial and/or interstitial extravillous trophoblasts reactive with the intercellular adhesion molecule-1 activation marker (P < .001). A significant correlation (R² = 0.84) was found between expression of spiral artery endothelial and interstitial extravillous trophoblast intercellular adhesion molecule-1 (P < .001) in activated placentas. Lesions of atherosis were found in 31.9% (30/94) of placentas with complete and/or partial failure of physiologic transformation of spiral arteries that were intercellular adhesion molecule-1-positive, in none of the 14 placentas with failure of physiologic transformation that were intercellular adhesion molecule-1-negative, and in none of the 15 placentas with complete spiral artery physiologic transformation without failure (P = .001). All placentas (30/30, 100%) with atherosis were identified in placentas having concomitant spiral artery endothelial and interstitial extravillous trophoblast activation.

CONCLUSION

Failure of spiral artery physiologic transformation in the placental basal plate is associated with interstitial extravillous trophoblast and arterial endothelial activation along with increased frequency of spiral artery atherosis. These findings may be used to improve the characterization of different disorders of the placental bed such as in refining the existing tools for the early prediction of risk for preterm, preeclamptic, and other abnormal pregnancies.

Maternal plasma-soluble ST2 concentrations are elevated prior to the development of early and late onset preeclampsia - a longitudinal study

OBJECTIVE

The objectives of this study were to determine (1) the longitudinal profile of plasma soluble ST2 (sST2) concentrations in patients with preeclampsia and those with uncomplicated pregnancies; (2) whether the changes in sST2 occur prior to the diagnosis of preeclampsia; and (3) the longitudinal sST2 profile of women with early or late preeclampsia.

MATERIALS AND METHODS

This longitudinal nested case-control study included singleton pregnancies in the following groups: (1) uncomplicated pregnancies (n = 160); and (2) those complicated by early (<34 weeks, n = 9) and late (≥34 weeks, n = 31) preeclampsia. sST2 concentrations were determined by enzyme-linked immunosorbent assays. Mixed-effects models were used for the longitudinal analysis.

RESULTS

(1) Plasma sST2 concentration profiles across gestation differed significantly among cases and controls (p < 0.0001); (2) women with early preeclampsia had higher mean sST2 concentrations than controls at >22 weeks of gestation; cases with late preeclampsia had higher mean concentrations at >33 weeks of gestation (both p < 0.05); and (3) these changes started approximately 6 weeks prior to clinical diagnosis.

CONCLUSIONS

Maternal plasma sST2 concentrations are elevated 6 weeks prior to the clinical diagnosis of preeclampsia. An increase in the maternal plasma concentration of sST2 may contribute to an exaggerated intravascular inflammatory response and/or the Th1/Th2 imbalance in some cases.

Vascular Growth Factors and Glomerular Disease

The glomerulus is a highly specialized microvascular bed that filters blood to form primary urinary filtrate. It contains four cell types: fenestrated endothelial cells, specialized vascular support cells termed podocytes, perivascular mesangial cells, and parietal epithelial cells. Glomerular cell-cell communication is critical for the development and maintenance of the glomerular filtration barrier. VEGF, ANGPT, EGF, SEMA3A, TGF-β, and CXCL12 signal in paracrine fashions between the podocytes, endothelium, and mesangium associated with the glomerular capillary bed to maintain filtration barrier function. In this review, we summarize the current understanding of these signaling pathways in the development and maintenance of the glomerulus and the progression of disease.

Pathophysiology of preeclampsia: an angiogenic imbalance and long-lasting systemic vascular dysfunction

Preeclampsia is a systemic vascular disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation. This condition targets several organs, including the kidneys, liver and brain, and is the leading cause of maternal and perinatal morbidity and mortality. Furthermore, recent evidence has revealed preeclampsia as a significant risk factor for future cardiovascular diseases in these women. Over the past decade, increasing evidence has indicated that maternal angiogenic imbalances caused by placental antiangiogenic factors play a central role in the systemic vascular dysfunction underling preeclampsia. The severity of the maternal antiangiogenic state correlates closely with maternal and perinatal outcomes. Assessing angiogenic imbalance and several vascular function tests have also emerged as a way of detecting systemic vascular dysfunction during pregnancy. This review summarizes the current understanding of the pathophysiology of preeclampsia, its clinical applications and clinical evidence for future cardiovascular risks.

The use of angiogenic biomarkers in maternal blood to identify which SGA fetuses will require a preterm delivery and mothers who will develop pre-eclampsia

OBJECTIVE

To determine (1) whether maternal plasma concentrations of angiogenic and anti-angiogenic factors can predict which mothers diagnosed with "suspected small for gestational age fetuses (sSGA)" will develop pre-eclampsia (PE) or require an indicated early preterm delivery (≤ 34 weeks of gestation); and (2) whether risk assessment performance is improved using these proteins in addition to clinical factors and Doppler parameters.

METHODS

This prospective cohort study included women with singleton pregnancies diagnosed with sSGA (estimated fetal weight <10th percentile) between 24 and 34 weeks of gestation (n = 314). Plasma concentrations of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1), soluble endoglin (sEng) and placental growth factor (PlGF) were determined in maternal blood obtained at the time of diagnosis. Doppler velocimetry of the umbilical (Umb) and uterine (UT) arteries was performed. The outcomes were (1) subsequent development of PE; and (2) indicated preterm delivery at ≤ 34 weeks of gestation (excluding deliveries as a result of spontaneous preterm labor, preterm pre-labor rupture of membranes or chorioamnionitis).

RESULTS

(1) The prevalence of PE and indicated preterm delivery was 9.2% (n = 29/314) and 7.3% (n = 23/314), respectively; (2) the area under the receiver operating characteristic curve (AUC) for the identification of patients who developed PE and/or required indicated preterm delivery was greater than 80% for the UT artery pulsatility index (PI) z-score and each biochemical marker (including their ratios) except sVEGFR-1 MoM; (3) using cutoffs at a false positive rate of 15%, women with abnormal plasma concentrations of angiogenic/anti-angiogenic factors were 7-13 times more likely to develop PE, and 12-22 times more likely to require preterm delivery than those with normal plasma MoM concentrations of these factors; (4) sEng, PlGF, PIGF/sEng and PIGF/sVEGFR-1 ratios MoM, each contributed significant information about the risk of PE beyond that provided by clinical factors and/or Doppler parameters: women who had low MoM values for these biomarkers were at 5-9 times greater risk of developing PE than women who had normal values, adjusting for clinical factors and Doppler parameters (adjusted odds ratio for PlGF: 9.1, PlGF/sEng: 5.6); (5) the concentrations of sVEGFR-1 and PlGF/sVEGFR-1 ratio MoM, each contributed significant information about the risk of indicated preterm delivery beyond that provided by clinical factors and/or Doppler parameters: women who had abnormal values were at 8-9 times greater risk for indicated preterm delivery, adjusting for clinical factors and Doppler parameters; and (6) for a two-stage risk assessment (Umb artery Doppler followed by Ut artery Doppler plus biochemical markers), among women who had normal Umb artery Doppler velocimetry (n = 279), 21 (7.5%) developed PE and 11 (52%) of these women were identified by an abnormal UT artery Doppler mean PI z-score (>2SD): a combination of PlGF/sEng ratio MoM concentration and abnormal UT artery Doppler velocimetry increased the sensitivity of abnormal UT artery Doppler velocimetry to 76% (16/21) at a fixed false-positive rate of 10% (p = 0.06).

CONCLUSION

Angiogenic and anti-angiogenic factors measured in maternal blood between 24 and 34 weeks of gestation can identify the majority of mothers diagnosed with "suspected SGA" who subsequently developed PE or those who later required preterm delivery ≤ 34 weeks of gestation. Moreover, incorporation of these biochemical markers significantly improves risk assessment performance for these outcomes beyond that of clinical factors and uterine and umbilical artery Doppler velocimetry.

Inflammatory biomarkers and spontaneous preterm birth among obese women

OBJECTIVE

To identify associations between second-trimester serum inflammatory biomarkers and preterm birth among obese women.

METHODS

In this nested case-control study, we compared 65 serum inflammatory biomarkers in obese women whose pregnancies resulted in early spontaneous preterm birth (<32 weeks gestation, n = 34) to obese women whose pregnancies resulted in term birth (n = 34). These women were selected from a larger population-based California cohort. Random forest and classification and regression tree techniques were employed to identify biomarkers of importance, and adjusted odds ratios (aORs) and 95% confidence intervals (CI) were estimated using logistic regression.

RESULTS

Random forest and classification and regression tree techniques found that soluble vascular endothelial growth factor receptor-3 (sVEGFR3), soluble interleukin-2 receptor alpha-chain (sIL-2RA) and soluble tumor necrosis factor receptor-1 (sTNFR1) were related to preterm birth. Using multivariable logistic regression to compare preterm cases and term controls, decreased serum levels of sVEGFR3 and increased serum levels of sIL-2RA and sTNFR1 were associated with increased risk of preterm birth among obese women, aOR = 3.2 (95% CI: 1.0-9.9), aOR = 2.8 (95% CI: 0.9-9.0), and aOR = 4.1 (95% CI: 1.2-14.1), respectively.

CONCLUSIONS

In this pilot study, we identified three serum biomarkers indicative of inflammation to be associated with spontaneous preterm birth among obese women: sVEGFR3, sIL-2RA and sTNFR1.

Racial-ethnic differences in midtrimester maternal serum levels of angiogenic and antiangiogenic factors

BACKGROUND

Little is known about racial-ethnic differences in the distribution of maternal serum levels of angiogenic and antiangiogenic factors and their associations with early-onset preeclampsia.

OBJECTIVE

We sought to investigate the distribution of midtrimester maternal serum levels of placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor 1 and their associations with early-onset preeclampsia in whites, Hispanics, and blacks.

STUDY DESIGN

A population-based nested case-control design was used to identify cases and controls of white, Hispanic, and black origin from a 2000 through 2007 live-birth cohort in 5 southern California counties. Cases included 197 women (90 whites, 67 Hispanics, and 40 blacks) with early-onset preeclampsia defined as hypertension and proteinuria with onset <32 weeks according to hospital records. Controls included a random sample of 2363 women without early-onset preeclampsia. Maternal serum specimens collected at 15-20 weeks' gestation as part of routine prenatal screening were tested for placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor 1. Serum levels of the 3 factors were log-normally distributed. Adjusted natural logarithmic means were compared between cases and controls and between racial-ethnic groups. Odds ratios and 95% confidence intervals derived from logistic regression models were calculated to measure the magnitude of the associations.

RESULTS

Cases showed lower adjusted logarithmic means of placental growth factor but higher adjusted logarithmic means of soluble endoglin than controls across all 3 groups (P < .05). Cases also had higher adjusted means of soluble vascular endothelial growth factor receptor 1 than controls in whites (7.75 vs 7.52 log pg/mL, P < .05) and Hispanics (7.73 vs 7.40 log pg/mL, P < .05) but not in blacks (7.85 vs 7.69 log pg/mL, P = .47). Blacks were found to have higher levels of placental growth factor in both cases and controls when compared to whites and Hispanics (adjusted means: 4.69 and 5.20 log pg/mL in blacks, 4.08 and 4.78 log pg/mL in whites, and 3.89 and 4.70 log pg/mL in Hispanics, respectively, P < .05). Hispanic cases had the highest adjusted mean of soluble endoglin compared to white and black cases (9.24, 9.05, and 8.93 log pg/mL, respectively, P < .05). The weakest association of early-onset preeclampsia with placental growth factor and soluble endoglin was observed in blacks. The adjusted odds ratio per log pg/mL increase of the 2 analytes were 0.219 (95% confidence interval, 0.124-0.385) and 5.02 (95% confidence interval, 2.56-9.86) in blacks in comparison to 0.048 (95% confidence interval, 0.026-0.088) and 36.87 (95% confidence interval, 17.00-79.96) in whites (P < .05) and 0.028 (95% confidence interval, 0.013-0.060) and 86.68 (95% confidence interval, 31.46-238.81) in Hispanics (P < .05), respectively. As for soluble vascular endothelial growth factor receptor 1, the association was not significantly different among the racial-ethnic groups.

CONCLUSION

Racial-ethnic differences were observed in the distribution of midtrimester maternal levels of placental growth factor and soluble endoglin and in the associations with early-onset preeclampsia. These differences should be considered in future studies to improve etiologic and prognostic understanding of early-onset preeclampsia.

Systematic Review of Micro-RNA Expression in Pre-Eclampsia Identifies a Number of Common Pathways Associated with the Disease

Background

Pre-eclampsia (PE) is a complex, multi-systemic condition of pregnancy which greatly impacts maternal and perinatal morbidity and mortality. MicroRNAs (miRs) are differentially expressed in PE and may be important in helping to understand the condition and its pathogenesis.

Methods

Case-control studies investigating expression of miRs in PE were collected through a systematic literature search. Data was extracted and compared from 58 studies to identify the most promising miRs associated with PE pathogenesis and identify areas of methodology which could account for often conflicting results.

Results

Some of the most frequently differentially expressed miRs in PE include miR-210, miR-223 and miR-126/126* which associate strongly with the etiological domains of hypoxia, immunology and angiogenesis. Members of the miR-515 family belonging to the imprinted chromosome 19 miR cluster with putative roles in trophoblast invasion were also found to be differentially expressed. Certain miRs appear to associate with more severe forms of PE such as miR-210 and the immune-related miR-181a and miR-15 families. Patterns of miR expression may help pinpoint key pathways (e.g. IL-6/miR-223/STAT3) and aid in untangling the heterogeneous nature of PE. The detectable presence of many PE-associated miRs in antenatal circulatory samples suggests their usefulness as predictive biomarkers. Further progress in ascertaining the clinical value of miRs and in understanding how they might contribute to pathogenesis is predicated upon resolving current methodological challenges in studies. These include differences in diagnostic criteria, cohort characteristics, sampling technique, RNA isolation and platform-dependent variation in miR profiling.

Conclusion

Reviewing studies of PE-associated miRs has revealed their potential as informants of underlying target genes and pathways relating to PE pathogenesis. However, the incongruity in results across current studies hampers their capacity to be useful biomarkers of the condition.

Gelsolin is an endogenous inhibitor of syncytiotrophoblast extracellular vesicle shedding in pregnancy

BACKGROUND

Preeclampsia, a pregnancy-specific inflammatory disorder, is characterized by high levels of anti-angiogenic protein, soluble fms-like tyrosine kinase 1 (sFlt1), in the maternal circulation. sFlt1 producing molecular machinery is present in syncytiotrophoblast extracellular vesicles that are released by the placenta into maternal plasma during normal pregnancy, a process greatly accelerated in preeclampsia. We hypothesized that syncytiotrophoblast extracellular vesicles exposes cytoplasmic actin to plasma resulting in depletion of plasma gelsolin (pGSN), an abundant plasma protein that scavenges circulating actin and other pro-inflammatory mediators.

OBJECTIVE

To test whether pGSN levels would be lower in preeclampsia and to assess whether recombinant human plasma gelsolin (rhpGSN) may promote placental health by decreasing shedding of syncytiotrophoblast extracellular vesicles.

METHODS

We tested pGSN levels in third trimester plasma samples from women with preeclampsia and non-hypertensive pregnancies. We then assessed whether rhpGSN may act as a negative regulator of syncytial shedding in placental explant culture and dynamic mechanical stretch studies.

RESULTS

pGSN levels fall in late pregnancy and decline further in preeclampsia patients. Recombinant human pGSN (rhpGSN) at 100μg/ml limits spontaneous syncytiotrophoblast vesicle release and sFlt1 protein dissemination by normal placental explants. Higher rhpGSN doses (500μg/ml) also limit syncytiotrophoblast vesicle and sFlt1 dissemination from preeclamptic placental explants. rhpGSN also mitigates syncytiotrophoblast vesicle during dynamic mechanical stretch.

CONCLUSIONS

1) pGSN, an anti-inflammatory factor of maternal origin is reduced in preeclampsia and may contribute to disease progression and 2) exogenous rhpGSN supplementation can limit the dissemination of toxic syncytiotrophoblast vesicle that characterizes the disease state.

Soluble fms-like tyrosine kinase 1 promotes angiotensin II sensitivity in preeclampsia

Preeclampsia is a hypertensive disorder of pregnancy in which patients develop profound sensitivity to vasopressors, such as angiotensin II, and is associated with substantial morbidity for the mother and fetus. Enhanced vasoconstrictor sensitivity and elevations in soluble fms-like tyrosine kinase 1 (sFLT1), a circulating antiangiogenic protein, precede clinical signs and symptoms of preeclampsia. Here, we report that overexpression of sFlt1 in pregnant mice induced angiotensin II sensitivity and hypertension by impairing endothelial nitric oxide synthase (eNOS) phosphorylation and promoting oxidative stress in the vasculature. Administration of the NOS inhibitor l-NAME to pregnant mice recapitulated the angiotensin sensitivity and oxidative stress observed with sFlt1 overexpression. Sildenafil, an FDA-approved phosphodiesterase 5 inhibitor that enhances NO signaling, reversed sFlt1-induced hypertension and angiotensin II sensitivity in the preeclampsia mouse model. Sildenafil treatment also improved uterine blood flow, decreased uterine vascular resistance, and improved fetal weights in comparison with untreated sFlt1-expressing mice. Finally, sFLT1 protein expression inversely correlated with reductions in eNOS phosphorylation in placental tissue of human preeclampsia patients. These data support the concept that endothelial dysfunction due to high circulating sFLT1 may be the primary event leading to enhanced vasoconstrictor sensitivity that is characteristic of preeclampsia and suggest that targeting sFLT1-induced pathways may be an avenue for treating preeclampsia and improving fetal outcomes.

Maternal plasma angiogenic index-1 (placental growth factor/soluble vascular endothelial growth factor receptor-1) is a biomarker for the burden of placental lesions consistent with uteroplacental underperfusion: a longitudinal case-cohort study

BACKGROUND

Placental lesions consistent with maternal vascular underperfusion (MVU) are thought to be pathogenically linked to preeclampsia, small-for-gestational-age newborns, fetal death, and spontaneous preterm labor and delivery; yet, these lesions cannot be diagnosed antenatally. We previously reported that patients with such conditions and lesions have an abnormal profile of the angiogenic placental growth factor (PlGF) and antiangiogenic factors (eg, soluble vascular endothelial growth factor receptor [sVEGFR]-1).

OBJECTIVE

The objectives of this study were to: (1) examine the relationship between the maternal plasma PlGF/sVEGFR-1 concentration ratio (referred to herein as angiogenic index-1) and the burden of histologic placental features consistent with MVU; and (2) test the hypothesis that angiogenic index-1 can identify patients in the midtrimester who are destined to deliver before 34 weeks of gestation with multiple (ie, ≥3) histologic placental features consistent with MVU.

STUDY DESIGN

A 2-stage case-cohort sampling strategy was used to select participants from among 4006 women with singleton gestations enrolled from 2006 through 2010 in a longitudinal study. Maternal plasma angiogenic index-1 ratios were determined using enzyme-linked immunosorbent assays. Placentas underwent histologic examination according to standardized protocols by experienced pediatric pathologists who were blinded to clinical diagnoses and pregnancy outcomes. The diagnosis of lesions consistent with MVU was made using criteria proposed by the Perinatal Section of the Society for Pediatric Pathology. Weighted analyses were performed to reflect the parent cohort; "n*" is used to reflect weighted frequencies.

RESULTS

(1) Angiogenic index-1 (PlGF/sVEGFR-1) concentration ratios were determined in 7560 plasma samples collected from 1499 study participants; (2) the prevalence of lesions consistent with MVU was 21% (n* = 833.9/3904) and 27% (n* = 11.4/42.7) of women with ≥3 MVU lesions delivered before 34 weeks of gestation; (3) a low angiogenic index-1 (<2.5th quantile for gestational age) in maternal plasma samples obtained within 48 hours of delivery had a sensitivity of 73% (n* = 8.3/11.4; 95% confidence interval [CI], 47-98%), a specificity of 94% (n* = 3130.9/3316.2; 95% CI, 94-95%), a positive likelihood ratio of 12.2, and a negative likelihood ratio of 0.29 in the identification of patients who delivered placentas with ≥3 MVU lesions at <34 weeks; (4) prospectively, at 20-23 weeks of gestation, a maternal plasma concentration of angiogenic index-1 <2.5th quantile identified 70% (n* = 7.2/10.3; 95% CI, 42-98%) of patients who delivered placentas with ≥3 MVU lesions before 34 weeks (specificity, 97% [n* = 2831.3/2918; 95% CI, 96-98%]; positive likelihood ratio, 23; negative likelihood ratio, 0.31); and (5) among women without obstetrical complications who delivered at term, angiogenic index-1 was lower in women with than without placental lesions consistent with MVU (P < .05).

CONCLUSION

Maternal plasma angiogenic index-1 (PlGF/sVEGFR-1) is the first biomarker for the burden of placental lesions consistent with MVU. We propose that an accumulation of these lesions in placentas delivered before 34 weeks is a histologic counterpart of an antiangiogenic profile.