Angiogenic factors for the prediction of preeclampsia in high-risk women

A mitochondrial regulator protein, MNRR1, is elevated in the maternal blood of women with preeclampsia

OBJECTIVE

Preeclampsia, one of the most serious obstetric complications, is a heterogenous disorder resulting from different pathologic processes. However, placental oxidative stress and an anti-angiogenic state play a crucial role. Mitochondria are a major source of cellular reactive oxygen species. Abnormalities in mitochondrial structures, proteins, and functions have been observed in the placentae of patients with preeclampsia, thus mitochondrial dysfunction has been implicated in the mechanism of the disease. Mitochondrial nuclear retrograde regulator 1 (MNRR1) is a newly characterized bi-organellar protein with pleiotropic functions. In the mitochondria, this protein regulates cytochrome c oxidase activity and reactive oxygen species production, whereas in the nucleus, it regulates the transcription of a number of genes including response to tissue hypoxia and inflammatory signals. Since MNRR1 expression changes in response to hypoxia and to an inflammatory signal, MNRR1 could be a part of mitochondrial dysfunction and involved in the pathologic process of preeclampsia. This study aimed to determine whether the plasma MNRR1 concentration of women with preeclampsia differed from that of normal pregnant women.

METHODS

This retrospective case-control study included 97 women with preeclampsia, stratified by gestational age at delivery into early (<34 weeks, n = 40) and late (≥34 weeks, n = 57) preeclampsia and by the presence or absence of placental lesions consistent with maternal vascular malperfusion (MVM), the histologic counterpart of an anti-angiogenic state. Women with an uncomplicated pregnancy at various gestational ages who delivered at term served as controls (n = 80) and were further stratified into early (n = 25) and late (n = 55) controls according to gestational age at venipuncture. Maternal plasma MNRR1 concentrations were determined by an enzyme-linked immunosorbent assay.

RESULTS

1) Women with preeclampsia at the time of diagnosis (either early or late disease) had a significantly higher median (interquartile range, IQR) plasma MNRR1 concentration than the controls [early preeclampsia: 1632 (924-2926) pg/mL vs. 630 (448-4002) pg/mL, p = .026, and late preeclampsia: 1833 (1441-5534) pg/mL vs. 910 (526-6178) pg/mL, p = .021]. Among women with early preeclampsia, those with MVM lesions in the placenta had the highest median (IQR) plasma MNRR1 concentration among the three groups [with MVM: 2066 (1070-3188) pg/mL vs. without MVM: 888 (812-1781) pg/mL, p = .03; and with MVM vs. control: 630 (448-4002) pg/mL, p = .04]. There was no significant difference in the median plasma MNRR1 concentration between women with early preeclampsia without MVM lesions and those with an uncomplicated pregnancy (p = .3). By contrast, women with late preeclampsia, regardless of MVM lesions, had a significantly higher median (IQR) plasma MNRR1 concentration than women in the control group [with MVM: 1609 (1392-3135) pg/mL vs. control: 910 (526-6178), p = .045; and without MVM: 2023 (1578-8936) pg/mL vs. control, p = .01].

CONCLUSIONS

MNRR1, a mitochondrial regulator protein, is elevated in the maternal plasma of women with preeclampsia (both early and late) at the time of diagnosis. These findings may reflect some degree of mitochondrial dysfunction, intravascular inflammation, or other unknown pathologic processes that characterize this obstetrical syndrome.

A dynamic prediction model for preeclampsia using the sFlt-1/PLGF ratio combined with multiple factors

OBJECTIVE

Preeclampsia (PE) is a pregnancy-related multi-organ disease and a significant cause of incidence rate and mortality of pregnant women and newborns worldwide. Delivery remains the only available treatment for PE. This study aims to establish a dynamic prediction model for PE.

METHODS

A total of 737 patients who visited our hospital from January 2021 to June 2022 were identified according to the inclusion and exclusion criteria, forming the primary dataset. Additionally, 176 singleton pregnant women who visited our hospital from July 2022 to November 2022 comprised the verification set. We investigated different gestational weeks of sFlt-1/PLGF (soluble FMS-like tyrosine kinase-1, placental growth factor) ratio combined with maternal characteristics and routine prenatal laboratory results in order to predict PE in each trimester. Multivariate logistic regression was used to establish the prediction model for PE at different gestational weeks. The discrimination, calibration, and clinical validity were utilized to evaluate predictive models as well as models in external validation queues.

RESULTS

At 20-24 weeks, the obtained prediction model for PE yielded an area under the curve of 0.568 (95% confidence interval, 0.479-0.657). At 25-29 weeks, the obtained prediction model for PE yielded an area under the curve of 0.773 (95% confidence interval, 0.703-0.842)and 0.731 (95% confidence interval, 0.653-0.809) at 30-34 weeks. After adding maternal factors, uterine artery pulsation index(Ut-IP), and other laboratory indicators to the sFlt-1/PLGF ratio, the predicted performance of PE improved. It found that the AUC improved to 0.826(95% confidence interval, 0.748 ∼ 0.904) at 20-24 weeks, 0.879 (95% confidence interval, 0.823 ∼ 0.935) at 25-29 weeks, and 0.862(95% confidence interval, 0.799 ∼ 0.925) at 30-34 weeks.The calibration plot of the prediction model indicates good predictive accuracy between the predicted probability of PE and the observed probability. Furthermore, decision-curve analysis showed an excellent clinical application value of the models.

CONCLUSION

Using the sFlt-1/PLGF ratio combined with multiple factors at 25-29 weeks can effectively predict PE, but the significance of re-examination in late pregnancy is not significant.

Preeclampsia at term can be classified into 2 clusters with different clinical characteristics and outcomes based on angiogenic biomarkers in maternal blood

BACKGROUND

An antiangiogenic state has emerged as a mechanism of disease in preeclampsia. Angiogenic biomarkers are used in the risk assessment of this syndrome, particularly of early disease. The role of an antiangiogenic state in late preeclampsia is unclear.

OBJECTIVE

This study aimed to determine the prevalence, characteristics, and clinical significance of angiogenic/antiangiogenic factor abnormalities in women with preeclampsia stratified according to gestational age at delivery.

STUDY DESIGN

Two studies were conducted: (1) a longitudinal nested case-control study comprising women with preeclampsia (n=151) and a control group (n=540); and (2) a case series of patients with preeclampsia (n=452). In patients with preeclampsia, blood was collected at the time of diagnosis. Plasma concentrations of placental growth factor and soluble fms-like tyrosine kinase-1 were determined by enzyme-linked immunosorbent assays. An abnormal angiogenic profile was defined as a plasma ratio of placental growth factor and soluble fms-like tyrosine kinase-1 expressed as a multiple of the median <10th percentile for gestational age based on values derived from the longitudinal study. The proportion of patients diagnosed with preeclampsia who had an abnormal angiogenic profile was determined in the case-series participants and stratified by gestational age at delivery into early (≤34 weeks), intermediate (34.1-36.9 weeks), and term (≥37 weeks) preeclampsia. The demographics, clinical characteristics, and pregnancy outcomes of women with preeclampsia with and without an abnormal angiogenic profile were compared.

RESULTS

The prevalence of an abnormal angiogenic profile was higher in preterm than in term preeclampsia (for early, intermediate, and term in the case-control study: 90%, 100%, and 39%; for the case series: 98%, 80%, and 55%, respectively). Women with preeclampsia at term who had an abnormal angiogenic profile were more frequently nulliparous (57% vs 35%), less likely to smoke (14% vs 26%), at greater risk for maternal (14% vs 5%) or neonatal (7% vs 1%) complications, and more often had placental lesions consistent with maternal vascular malperfusion (42% vs 23%; all, P<.05) than those without an abnormal profile. Women with preeclampsia at term who had a normal angiogenic profile had a higher frequency of chronic hypertension (36% vs 21%) and were more likely to have class ≥2 obesity (41% vs 23%) than those with an abnormal profile (both, P<.05).

CONCLUSION

Patients with early preeclampsia had an abnormal angiogenic profile in virtually all cases, whereas only 50% of women with preeclampsia at term had such abnormalities. The profile of angiogenic biomarkers can be used to classify patients with preeclampsia at term, on the basis of mechanisms of disease, into 2 clusters, which have different demographics, clinical characteristics, and risks of adverse maternal and neonatal outcomes. These findings provide a simple approach to classify preeclampsia at term and have implications for future clinical care and research.

The association between sleep-disordered breathing and maternal endothelial and metabolic markers in pregnancies complicated by obesity

STUDY OBJECTIVES

To evaluate the impact of sleep-disordered breathing (SDB) on vascular, angiogenic and metabolic analytes in pregnancy.

METHODS

Participants with a body mass index ≥30 kg/m2 underwent polysomnography at 14-20 weeks gestation (visit 1). Participants with SDB (defined as an apnea-hypopnea index ≥5 events/h) were then enrolled in a separate trial. SDB-negative participants returned for a polysomnogram at 28-31 weeks (visit 2) and were recategorized as persistent-negative SDB or new-onset SDB. Mean arterial blood pressure, mean uterine artery Doppler pulsatility index, endoglin, soluble Feline McDonough Sarcoma-like tyrosine kinase 1, placental growth factor, and the homeostatic model assessment for insulin resistance were measured after each visit. Our primary outcome was a composite of uterine artery Doppler pulsatility index, soluble FMS-like tyrosine kinase 1/placental growth factor ratio, and homeostatic model assessment for insulin resistance. For secondary analyses, each outcome variable was analyzed independently.

RESULTS

A total of 242 and 130 participants completed visit 1 and visit 2, respectively. Newly diagnosed SDB was present in 37% of individuals at visit 1 and 31% of individuals at visit 2. No significant differences in our composite outcome vector were observed in individuals with and without SDB at either visit. In our secondary analysis, mean arterial blood pressure (88.7 ± 7.3 mm Hg vs 85.4 ± 7.1 mm Hg, P = .04) and fasting glucose (92.4 ± 15.2 mg/dL vs 86.6 ± 11.5 mg/dL, P = .05) were higher in participants with early pregnancy SDB. These associations were not observed for new-onset SDB. No associations were observed between uterine artery Doppler pulsatility index and angiogenic markers and SDB in pregnancy.

CONCLUSIONS

SDB in early pregnancy was not associated with our composite primary outcome but was associated with higher mean arterial blood pressure and fasting glucose. The pathophysiologic changes that occur in pregnant individuals with SDB and how they lead to an increased risk of preeclampsia and gestational diabetes remain poorly understood.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Sleep Disordered Breathing, Obesity and Pregnancy Study (SOAP); URL: https://clinicaltrials.gov/ct2/show/NCT02086448; Identifier: NCT02086448.

CITATION

Onslow ML, Wolsk J, Wisniewski S, et al. The association between sleep-disordered breathing and maternal endothelial and metabolic markers in pregnancies complicated by obesity. J Clin Sleep Med. 2023;19(1):97-109.

The central role of natural killer cells in preeclampsia

Preeclampsia (PE) is a disease that is unique to pregnancy and affects multiple systems. It can lead to maternal and perinatal mortality. The precise etiology of PE is unclear. Patients with PE may have systemic or local immune abnormalities. A group of researchers has proposed that the immune communication between the fetus and mother is primarily moderated by natural killer (NK) cells as opposed to T cells, since NK cells are the most abundant immune cells in the uterus. This review examines the immunological roles of NK cells in the pathogenesis of PE. Our aim is to provide obstetricians with a comprehensive and updated research progress report on NK cells in PE patients. It has been reported that decidual NK (dNK) cells contribute to the process of uterine spiral artery remodeling and can modulate trophoblast invasion. Additionally, dNK cells can stimulate fetal growth and regulate delivery. It appears that the count or proportion of circulating NK cells is elevated in patients with or at risk for PE. Changes in the number or function of dNK cells may be the cause of PE. The Th1/Th2 equilibrium in PE has gradually shifted to an NK1/NK2 equilibrium based on cytokine production. An improper combination of killer cell immunoglobulin-like receptor (KIR) and human leukocyte antigen (HLA)-C may lead to insufficient activation of dNK cells, thereby causing PE. In the etiology of PE, NK cells appear to exert a central effect in both peripheral blood and the maternal-fetal interface. To maintain immune equilibrium both locally and systemically, it is necessary to take therapeutic measures directed at NK cells.

COVID-19 associated liver injury: A general review with special consideration of pregnancy and obstetric outcomes

Liver injury is an increasingly recognized extra-pulmonary manifestation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Coronavirus disease 2019 (COVID-19) associated liver injury (COVALI) is a clinical syndrome encompassing all patients with biochemical liver injury identified in the setting of SARS-CoV-2 infection. Despite profound clinical implications, its pathophysiology is poorly understood. Unfortunately, most information on COVALI is derived from the general population and may not be applicable to individuals under-represented in research, including pregnant individuals. This manuscript reviews: Clinical features of COVALI, leading theories of COVALI, and existing literature on COVALI during pregnancy, a topic not widely explored in the literature. Ultimately, we synthesized data from the general and perinatal populations that demonstrates COVALI to be a hepatocellular transaminitis that is likely induced by systemic inflammation and that is strongly associated with disease severity and poorer clinical outcome, and offered perspective on approaching transaminitis in the potentially COVID-19 positive patient in the obstetric setting.

Proteinuria during pregnancy: definition, pathophysiology, methodology, and clinical significance

Qualitative and quantitative measurement of urine protein excretion is one of the most common tests performed during pregnancy. For more than 100 years, proteinuria was necessary for the diagnosis of preeclampsia, but recent guidelines recommend that proteinuria is sufficient but not necessary for the diagnosis. Still, in clinical practice, most patients with gestational hypertension will be diagnosed as having preeclampsia based on the presence of proteinuria. Although the reference standard for measuring urinary protein excretion is a 24-hour urine collection, spot urine protein-to-creatinine ratio is a reasonable "rule-out" test for proteinuria. Urine dipstick screening for proteinuria does not provide any clinical benefit and should not be used to diagnose proteinuria. The classic cutoff cited to define proteinuria during pregnancy is a value of >300 mg/24 hours or a urine protein-to-creatinine ratio of at least 0.3. Using this cutoff, the rate of isolated proteinuria in pregnancy may reach 8%, whereas preeclampsia occurs among 3% to 8% of pregnancies. Although this threshold is widely accepted, its origin is not based on evidence on adverse pregnancy outcomes but rather on expert opinion and results of small studies. After reviewing the available data, the most important factor that influences maternal and neonatal outcome is the severity of blood pressures and presence of end organ damage, rather than the excess protein excretion. Because the management of gestational hypertension and preeclampsia without severe features is almost identical in frequency of surveillance and timing of delivery, the separation into 2 disorders is unnecessary. If the management of women with gestational hypertension with a positive assessment of proteinuria will not change, we believe that urine assessment for proteinuria is unnecessary in women who develop new-onset blood pressure at or after 20 weeks' gestation. Furthermore, we do not recommend repeated measurement of proteinuria for women with preeclampsia, the amount of proteinuria does not seem to be related to poor maternal and neonatal outcomes, and monitoring proteinuria may lead to unindicated preterm deliveries and related neonatal complications. Our current diagnosis of preeclampsia in women with chronic kidney disease may be based on a change in protein excretion, a baseline protein excretion evaluation is critical in certain conditions such as chronic hypertension, diabetes, and autoimmune or other renal disorders. The current definition of superimposed preeclampsia possesses a diagnostic dilemma, and it is unclear whether a change in the baseline proteinuria reflects another systemic disease such as preeclampsia or whether women with chronic disease such as chronic hypertension or diabetes will experience a different "normal" pattern of protein excretion during pregnancy. Finally, limited data are available regarding angiogenic and other biomarkers in women with chronic kidney disease as a potential aid in distinguishing the worsening of baseline chronic kidney disease and chronic hypertension from superimposed preeclampsia.

Evaluation of Angiogenic Factors (PlGF and sFlt-1) in Pre-eclampsia Diagnosis

OBJECTIVE

 Recent observations support the hypothesis that an imbalance between angiogenic factors has a fundamental role in the pathogenesis of pre-eclampsia and is responsible for the clinical manifestations of the disease. The goal of the present study was to evaluate the sensitivity, specificity, and the best accuracy level of Soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), and sFlt-1/PlGF ratio in maternal serum and protein/creatinine ratio in urine sample to define the best cutoff point of these tests to discriminate between the patients with gestational hypertension and the patients with pre-eclampsia, to evaluate the possibility of using them as diagnostic methods.

METHODS

 A prospective longitudinal study was performed, and blood samples were collected from 95 pregnant patients with hypertension to measure serum concentrations of biomarkers sFlt-1 and PlGF. Urine samples were collected for protein screening. Significance was set as p < 0.05.

RESULTS

 The sFlt-1/PlGF ratio demonstrated a sensitivity of 57.5% and a specificity of 60% using 50.4 as a cutoff point. The test that showed the best accuracy in the diagnosis of pre-eclampsia was protein/creatinine ratio, with a sensitivity of 78.9% and a specificity of 70% using 0.4 as a cutoff point and showing an area under the receiver operating characteristic curve of 0.80 (p < 0.001).

CONCLUSION

 No studied laboratory test proved to be fairly accurate for the diagnosis of pre-eclampsia, except for the protein/creatinine ratio. The evidence is insufficient to recommend biomarkers sFlt-1 and PlGF to be used for the diagnosis of pre-eclampsia.

Circular RNA hsa_circ_0007121 regulates proliferation, migration, invasion, and epithelial-mesenchymal transition of trophoblast cells by miR-182-5p/PGF axis in preeclampsia

Background

Mounting evidence has revealed that abnormal expression of circular RNAs play pivotal roles in many human diseases including preeclampsia (PE). While human sapiens circular RNA 0007121 (hsa_circ_0007121) has been verified to be downregulated in human placental tissues, the underlying mechanisms were still unclear. This research aims to investigate the effect and underlying mechanisms of hsa_circ_0007121 in preeclampsia.

Methods

The expression of hsa_circ_0007121, microRNA (miR)-182-5p, and placental growth factor (PGF) was assessed by quantitative reverse transcription polymerase chain reaction in PE placentas relative to the expression in normal pregnancy placentas. After transfection, cell counting kit-8 assay was employed to detect cell proliferation. Cell migration and invasion were tested by the transwell assay. The relative level of epithelial–mesenchymal transition (EMT)-related proteins in HTR-8/SVneo cells and PGF in placentas samples were measured by western blot. The relationship between miR-182-5p and hsa_circ_0007121 or PGF was predicated by circular RNA interactome or ENCORI and verified by dual-luciferase reporter assay and RNA immunoprecipitation assay.

Results

The levels of hsa_circ_0007121 and PGF were significantly declined in PE placental tissues and HTR-8/SVneo cells, whereas miR-182-5p had an opposite result. Downregulation of hsa_circ_0007121 obviously inhibited HTR-8/SVneo cell proliferation, migration, invasion, and EMT, while upregulation of hsa_circ_0007121 promoted this process. Besides, miR-182-5p was a target gene of hsa_circ_0007121 and could target PGF. Further analysis indicated that hsa_circ_0007121 regulated the proliferation, migration, invasion, and EMT of HTR-8/SVneo cells via altering PGF expression by interacting with miR-182-5p.

Conclusion

Hsa_circ_0007121 mediated the progression of PE via miR-182-5p/PGF axis.

Differential regulation of a placental SAM68 and sFLT1 gene pathway and the relevance to maternal vitamin D sufficiency

OBJECTIVE

The goal of this study was to determine if an axis of placental gene expression associated with early onset and severe preeclampsia (EOSPE) was operative in term pregnancy and correlated with vitamin D sufficiency.

METHODS

qPCR analysis of NKX2-5, SAM68, sFLT1 and membrane bound VEGFR1/FLT1 mRNA expression was conducted in placentas from 43 subjects enrolled in a vitamin D3 pregnancy supplementation trial. Pair-wise rank order correlations between patient-specific gene expression levels were calculated, and their relationship to maternal 25(OH)D status was assessed by a two-sample Wilcoxon test. Additionally, we probed the mechanistic link between SAM68 and sFLT1 using siRNA depletion in a human trophoblast cell line model.

RESULTS

Positive and highly significant correlations were found between SAM68 vs. sFLT1 and SAM68 vs. FLT1 expression levels, as were significant and differential correlations between the expression of these genes and perinatal 25(OH)D status. The variability when stratified by race/ethnicity was qualitatively distinct from those previously observed in EOSPE. Mechanistic studies confirmed a functional role for SAM68 protein in the regulation of sFLT1 expression. NKX2-5 expression was not significantly correlated with sFLT1 or SAM68 expression in these samples, suggesting that its expression may be significant at earlier stages of pregnancy or be restricted to pathological settings.

CONCLUSIONS

These data further support our overarching hypothesis that SAM68 expression is a key determinant of VEGFR1 isoform expression in the placenta, and provide additional insights into how this gene pathway may be differentially deployed or modified in normal and pathological pregnancies.

Effect of Low-Dose Aspirin on Soluble FMS-Like Tyrosine Kinase 1/Placental Growth Factor (sFlt-1/PlGF Ratio) in Pregnancies at High Risk for the Development of Preeclampsia

BACKGROUND

Soluble FMS-like Tyrosine Kinase 1 (sFlt-1) and placental growth factor (PlGF) have been reported to be highly predictive several weeks before the onset of preeclampsia.

OBJECTIVE

To investigate longitudinal changes of serum levels sFlt-1 and PlGF in pregnant women at high risk for the development of preeclampsia and to reveal an impact of aspirin on maternal serum concentrations of sFlt-1 and PlGF.

METHODS

This was a prospective longitudinal study in 394 women with various risk factors for the development of preeclampsia (chronic hypertension, antiphospholipid syndrome/APS or systemic lupus erythematosus/SLE, thrombophilia, women with a history of preeclampsia, pathologic first trimester screening for preeclampsia) and 68 healthy women. Serum levels of sFlt-1 and PlGF were measured prospectively at 4-week intervals (from gestational weeks 12 until postpartum).

RESULTS

The sFlt-1/PlGF ratio was significantly higher in women with an adverse obstetric outcome compared to women with a normal pregnancy, starting between 20 and 24 weeks of gestation. There was no effect of aspirin on sFlt-1/PlGF ratio in women with chronic hypertension, APS/SLE, thrombophilia and controls. The use of aspirin showed a trend towards an improvement of the sFlt-1/PlGF ratio in women with preeclampsia in a previous pregnancy and a significant effect on the sFlt-1/PlGF ratio in women with a pathologic first trimester screening for preeclampsia.

CONCLUSIONS

Our findings reveal an impact of aspirin on sFlt-1/PlGF ratio in women with a pathologic first trimester screening for preeclampsia, strongly supporting its prophylactic use.

Preeclampsia: the role of persistent endothelial cells in uteroplacental arteries

We explore the potential role of the endothelial lining of uteroplacental arteries in the pathogenesis of preeclampsia, a severe pregnancy disorder characterized by incomplete invasion of the uterine vasculature by extravillous trophoblast and angiogenic imbalance. In normal pregnancy, the endothelium disappears progressively from the uteroplacental arteries and is replaced by trophoblast and deposition of fibrofibrinoid structure, underpinning the so-called physiological transformation of uterine spiral arteries. We hypothesize that partial persistence of the endothelium, albeit injured, initiates a chain of events leading to the emergence of preeclampsia in 3 sequential stages. The first stage results in retention of the endothelium in uteroplacental arteries secondary to incomplete physiological transformation of the vessels. Consequently, the uteroplacental vessels are reactive to pathological cues, which drives local arteriopathy. The second stage starts with progressive reduction in uteroplacental blood flow, generating oxidative stress in the whole placenta, and heightened maternal inflammation in response to circulating trophoblastic debris. In the third stage, generalized endotheliosis causes systemic angiogenic imbalance, hypertension, and other clinical manifestation of preeclampsia.

Narrowing abdominal aorta and vein is a simple and useful method for preparing a mice model of gestational hypertension

Hypertensive disorder of pregnancy (HDP) is a major cause of maternal morbidity and mortality, fetal growth restriction (FGR), and premature delivery. Soluble fms-like tyrosine kinase-1 (sFLT-1) is significantly elevated in pre-eclamptic women. Making animal models of hypertensive pregnancy is costly and requires advanced equipment. We established a gestational hypertension (GH), one of the HDP subtypes, mouse model by narrowing the abdominal aorta and vein together with a medical drip tube on day 10.5 of gestation. Systolic and diastolic blood pressure on day 18.5 of gestation in the narrowed aorta and vein (NAV) group were significantly higher than those in the control group. Fetal weight decreased in the NAV group. Serum sFLT-1 was significantly increased in the NAV group on day 18.5 of gestation compared to the control group. After delivery, blood pressure and serum sFLT-1 level did not differ between the NAV and the control groups. These parameters normalized postpartum. We established a novel GH mouse model through an easy operative procedure using a simple device. In this NAV model, blood pressure and serum sFLT-1 level were increased on day 18.5 of gestation, and normalized promptly after delivery. The mouse model mimics human GH, and is suitable for the development of other treatments.

[Potential value of placental angiogenic factors as biomarkers in preeclampsia for clinical physicians]

The role of angiogenic factors in the onset of clinical manifestations of preeclampsia was demonstrated in 2003 by the implication of sFlt-1, PlGF and VEGF, and in 2006 by the implication of soluble endoglin. Placental ischemia and inflammation observed in preeclampsia alter both the production and progression of angiogenic factors during pregnancy. During the first trimester, the combination of PlGF with clinical, biophysical and biological factors results in a better test than the conventional one. However, the clinical value of this method remains to be confirmed. During the second and third trimesters, the sFlt-1/PlGF ratio may be used, with or without pre-existing renal disease, for short-term prediction, diagnosis, and prognosis, and to evaluate the effectiveness of preeclampsia treatment. While a sFlt-1/PlGF ratio<38 and≤33, respectively, rules out the short-term onset and diagnosis of preeclampsia, a sFlt-1/PlGF ratio≥85 between 20 and 34 weeks of pregnancy and≥110 beyond 34 weeks of pregnancy confirms a diagnosis of preeclampsia. Angiogenic and non-angiogenic preeclampsia are identified by a sFlt-1PlGF≥85 and<85, respectively, with the risk of maternal and fetal complications at two weeks differing between the two. Similarly, a sFlt-1/PlGF ratio>665 and>205, respectively, is a good short-term predictor of adverse outcomes of early and late-onset preeclampsia. These values could be incorporated into future guidelines for better clinical management of preeclampsia.

Midpregnancy prediction of pre-eclampsia using serum biomarkers sFlt-1 and PlGF

OBJECTIVES

Pre-eclampsia remains a significant cause of morbidity and mortality. Placental biomarkers soluble Fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) have been investigated previously for their ability to predict pre-eclampsia. We compared the performance of these biomarkers for midpregnancy pre-eclampsia prediction using three different immunoassay platforms.

STUDY DESIGN

Prospective study including singleton pregnancies 19-22 weeks' gestation. Maternal bloods were collected at recruitment. Screening performances using receiver operating characteristic (ROC) curves for PlGF and sFlt-1/PlGF ratio raw data and MoM values in isolation were evaluated for three immunoassay platforms using selected cut-off values.

MAIN OUTCOME MEASURES

Pre-eclampsia was defined as early-onset (<34 weeks' at delivery) and preterm (<37 weeks' at delivery).

RESULTS

For prediction of preterm pre-eclampsia, PlGF MoM and sFlt-1/PlGF ratio MoM performed similarly, with areas under the curve (AUC), detection rates (DR) and false positive rates (FPR) for PlGF MoM and sFlt-1/PlGF ratio MoM being 0.77-0.79 and 0.71-0.74, 62.5% for both and 9.7-14.9 and 10.7-17.7, respectively. For the prediction of early-onset pre-eclampsia, sFlt-1/PlGF ratio raw data and MoM values performed similarly, with AUC, DR and FPR being 0.92-0.97 and 0.93-0.96, 100% for both, and 4.13-16.9 and 9.4-12.2, respectively.

CONCLUSIONS

For midpregnancy prediction of preterm pre-eclampsia, PlGF MoM for all three platforms and sFlt-1/PlGF ratio MoM for the two platforms that tested sFlt-1 performed similarly. For midpregnancy prediction of early-onset pre-eclampsia at midpregnancy, sFlt-1/PlGF ratio raw data and MoM values using the early-onset cut-off for the two platforms that tested sFlt-1 gave similar performance from a clinical perspective.

Loss of placental growth factor ameliorates maternal hypertension and preeclampsia in mice

Preeclampsia remains a clinical challenge due to its poorly understood pathogenesis. A prevailing notion is that increased placental production of soluble fms-like tyrosine kinase-1 (sFlt-1) causes the maternal syndrome by inhibiting proangiogenic placental growth factor (PlGF) and VEGF. However, the significance of PlGF suppression in preeclampsia is uncertain. To test whether preeclampsia results from the imbalance of angiogenic factors reflected by an abnormal sFlt-1/PlGF ratio, we studied PlGF KO (Pgf-/-) mice and noted that the mice did not develop signs or sequelae of preeclampsia despite a marked elevation in circulating sFLT-1. Notably, PlGF KO mice had morphologically distinct placentas, showing an accumulation of junctional zone glycogen. We next considered the role of placental PlGF in an established model of preeclampsia (pregnant catechol-O-methyltransferase-deficient [COMT-deficient] mice) by generating mice with deletions in both the Pgf and Comt genes. Deletion of placental PlGF in the context of COMT loss resulted in a reduction in maternal blood pressure and increased placental glycogen, indicating that loss of PlGF might be protective against the development of preeclampsia. These results identify a role for PlGF in placental development and support a complex model for the pathogenesis of preeclampsia beyond an angiogenic factor imbalance.

Novel biomarker profiles in experimental aged maternal mice with hypertensive disorders of pregnancy

Recently, advanced maternal age (AMA) has increased in Western countries because of late marriage and advances in assisted reproductive technology. One major complication of AMA is hypertensive disorders of pregnancy (HDP). While clinical investigations into human AMA have been reported, there has been limited information obtained from basic research. In this investigation, we established the AMA mouse model using aged pregnant ICR mice. We demonstrated that the phenotypes of aged pregnant ICR mice reflect the same characteristics as human AMA. The significant findings of our investigation are as follows: (1) The AMA mouse model manifested the same complication phenotypes of human AMA, including maternal obesity, declining fertility, small for gestational age, and a higher rate of intrauterine fetal death; (2) The AMA mouse model exhibited an increasing systolic blood pressure at late gestation (108.2 ± 7.7 vs. 92.7 ± 5.7 mmHg, P < 0.01) that normalized after delivery similar to human HDP patients; and (3) While HDP and placental dysfunction are complicated, AMA mice and human HDP AMA patients manifested a low serum soluble fms-like tyrosine kinase-1 (sFlt-1) level in late gestation (AMA group vs. control group, mice, 16800.0 ± 10709.5 vs. 26611.9 ± 8702.0 pg/mL, respectively, P < 0.01; human, 8507.6 ± 3298.7 vs. 14816.9 ± 5413.5 pg/mL, respectively, P < 0.05). In conclusion, the aged pregnant mouse model resembled human AMA. The AMA mouse model was complicated with HDP despite the low serum sFlt-1 level. Our findings provide evidence that the serum sFlt-1 level does not necessarily reflect the conventional pathogenesis of HDP in aged human and murine pregnancies and may contribute to the future management of HDP in AMA.

A best-practice position statement on pregnancy after kidney transplantation: focusing on the unsolved questions. The Kidney and Pregnancy Study Group of the Italian Society of Nephrology

Kidney transplantation (KT) is often considered to be the method best able to restore fertility in a woman with chronic kidney disease (CKD). However, pregnancies in KT are not devoid of risks (in particular prematurity, small for gestational age babies, and the hypertensive disorders of pregnancy). An ideal profile of the potential KT mother includes “normal” or “good” kidney function (usually defined as glomerular filtration rate, GFR ≥ 60 ml/min), scant or no proteinuria (usually defined as below 500 mg/dl), normal or well controlled blood pressure (one drug only and no sign of end-organ damage), no recent acute rejection, good compliance and low-dose immunosuppression, without the use of potentially teratogen drugs (mycophenolic acid and m-Tor inhibitors) and an interval of at least 1–2 years after transplantation. In this setting, there is little if any risk of worsening of the kidney function. Less is known about how to manage “non-ideal” situations, such as a pregnancy a short time after KT, or one in the context of hypertension or a failing kidney. The aim of this position statement by the Kidney and Pregnancy Group of the Italian Society of Nephrology is to review the literature and discuss what is known about the clinical management of CKD after KT, with particular attention to women who start a pregnancy in non-ideal conditions. While the experience in such cases is limited, the risks of worsening the renal function are probably higher in cases with markedly reduced kidney function, and in the presence of proteinuria. Well-controlled hypertension alone seems less relevant for outcomes, even if its effect is probably multiplicative if combined with low GFR and proteinuria. As in other settings of kidney disease, superimposed preeclampsia (PE) is differently defined and this impairs calculating its real incidence. No specific difference between non-teratogen immunosuppressive drugs has been shown, but calcineurin inhibitors have been associated with foetal growth restriction and low birth weight. The clinical choices in cases at high risk for malformations or kidney function impairment (pregnancies under mycophenolic acid or with severe kidney-function impairment) require merging clinical and ethical approaches in which, beside the mother and child dyad, the grafted kidney is a crucial “third element”.

Placental growth factor (alone or in combination with soluble fms-like tyrosine kinase 1) as an aid to the assessment of women with suspected pre-eclampsia: systematic review and economic analysis

BACKGROUND

Pre-eclampsia (PE) prediction based on blood pressure, presence of protein in the urine, symptoms and laboratory test abnormalities can result in false-positive diagnoses. This may lead to unnecessary antenatal admissions and preterm delivery. Blood tests that measure placental growth factor (PlGF) or the ratio of soluble fms-like tyrosine kinase 1 (sFlt-1) to PlGF could aid prediction of PE if either were added to routine clinical assessment or used as a replacement for proteinuria testing.

OBJECTIVES

To evaluate the diagnostic accuracy and cost-effectiveness of PlGF-based tests for patients referred to secondary care with suspected PE in weeks 20-37 of pregnancy.

DESIGN

Systematic reviews and an economic analysis.

DATA SOURCES

Bibliographic databases including MEDLINE, EMBASE, Web of Science and The Cochrane Library and Database of Abstracts of Reviews of Effects were searched up to July 2015 for English-language references. Conferences, websites, systematic reviews and confidential company submissions were also accessed.

REVIEW METHODS

Systematic reviews of test accuracy and economic studies were conducted to inform an economic analysis. Test accuracy studies were required to include women with suspected PE and report quantitatively the accuracy of PlGF-based tests; their risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) criteria. The economic studies review had broad eligibility criteria to capture any types of economic analysis; critical appraisal employed standard checklists consistent with National Institute for Health and Care Excellence criteria. Study selection, critical appraisal and data extraction in both reviews were performed by two reviewers.

ECONOMIC ANALYSIS

An independent economic analysis was conducted based on a decision tree model, using the best evidence available. The model evaluates costs (2014, GBP) from a NHS and Personal Social Services perspective. Given the short analysis time horizon, no discounting was undertaken.

RESULTS

Four studies were included in the systematic review of test accuracy: two on Alere's Triage^® PlGF test (Alere, Inc., San Diego, CA, USA) for predicting PE requiring delivery within a specified time and two on Roche Diagnostics' Elecsys^® sFlt-1 to PlGF ratio test (Roche Diagnostics GmbH, Mannheim, Germany) for predicting PE within a specified time. Three studies were included in the systematic review of economic studies, and two confidential company economic analyses were assessed separately. Study heterogeneity precluded meta-analyses of test accuracy or cost-analysis outcomes, so narrative syntheses were conducted to inform the independent economic model. The model predicts that, when supplementing routine clinical assessment for rule-out and rule-in of PE, the two tests would be cost-saving in weeks 20-35 of gestation, and marginally cost-saving in weeks 35-37, but with minuscule impact on quality of life. Length of neonatal intensive care unit stay was the most influential parameter in sensitivity analyses. All other sensitivity analyses had negligible effects on results.

LIMITATIONS

No head-to-head comparisons of the tests were identified. No studies investigated accuracy of PlGF-based tests when used as a replacement for proteinuria testing. Test accuracy studies were found to be at high risk of clinical review bias.

CONCLUSIONS

The Triage and Elecsys tests would save money if added to routine clinical assessment for PE. The magnitude of savings is uncertain, but the tests remain cost-saving under worst-case assumptions. Further research is required to clarify how the test results would be interpreted and applied in clinical practice.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015017670.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Placental Growth Factor as a Prognostic Tool in Women With Hypertensive Disorders of Pregnancy: A Systematic Review

Supplemental Digital Content is available in the text.

The PlGF (placental growth factor) has been largely demonstrated to be associated with the diagnosis of the hypertensive disorders of pregnancy (HDPs); however, it is unclear how useful it is for the prognosis of the condition. Our objective was to provide a summary of important findings of its prognostic ability by systematically reviewing studies that examined the ability of the PlGF, either independently or combined with other factors, to predict maternal and fetal complications resulting from the HDPs. We included studies published before January 30, 2017, reporting on the use of the PlGF as a prognostic test for women with confirmed HDPs or suspected preeclampsia. Of the 220 abstracts identified through MEDLINE, Embase, and CINAHL (Cumulative Index to Nursing and Allied Health Literature), 17 studies were eligible for our review. Prognostic performance was evaluated by sensitivity, specificity, likelihood ratios, and area under the receiver operating characteristic curve. PlGF showed moderate-to-high evidence (likelihood ratios of ≥5 or ≤0.2 or area under the receiver operating characteristic curves ≥0.70) for identifying women at the highest risk of preterm delivery or neonatal outcomes (10/12 studies) but showed no clinically useful performance for the prediction of adverse maternal outcomes. PlGF may aid in the management of women with HDPs to avert fetal complications. Future studies should determine an optimum threshold for the marker to guide delivery and should examine whether its use for predicting adverse maternal outcomes in women with HDPs can be improved.

Angiogenic factors for prediction of preeclampsia and intrauterine growth restriction onset in high-risk women: AngioPred study

OBJECTIVE

The study aimed to compare the level of two angiogenic factors, soluble fms-like tyrosine kinase-1 (sFlt1) and soluble endoglin (sEng), for the prediction of preeclampsia and intrauterine growth restriction in high-risk pregnant women.

METHODS

A prospective multicenter cohort study of 200 pregnant patients was conducted between June 2008 and October 2010. sFlt1 and sEng were measured by enzyme-linked immunosorbent assay.

RESULTS

Forty-five patients developed a placenta-mediated adverse pregnancy outcome. Plasma levels of sFlt1 and sEng were higher in patients who will experience a preeclampsia at 28, 32, and 36 weeks compared with patients with no complication. The same results were observed for intrauterine growth restriction. Plasma levels of sFlt1 and sEng were not significantly different for patients with preeclampsia compare to patients with intrauterine growth restriction. Patients with early pre-eclampsia (PE) had very high rates of angiogenic factors at 20, 24, and 28 weeks. Patients with late PE and early and late intrauterine growth retardation (IUGR) had high rates at 32 and 36 weeks.

CONCLUSION

In high-risk women, angiogenic factors are disturbed before the onset of preeclampsia and this is true for intrauterine growth restriction.

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.

Low maternal serum pregnancy-associated plasma protein-A as a risk factor of preeclampsia

INTRODUCTION

Low levels of pregnancy-associated plasma protein-A (PAPP-A) might be associated with abnormal placentation, leading to the development of preeclampsia during late gestation. We aimed to determine the association between low serum PAPP-A levels and rates of preeclampsia in Thai women with otherwise low-risk pregnancies.

METHODS

A cohort study was conducted on consecutive singleton pregnancies undergoing first trimester screening for fetal Down syndrome at a tertiary centre hospital. A prospective database was assessed for patient records, including PAPP-A levels, pregnancy outcomes and obstetrics complications. Pregnancies with potential causes of preeclampsia were excluded. Enrolled women were categorised into two groups: women with normal PAPP-A levels (≥ 10th percentile; control group); and those with low PAPP-A levels (< 10th percentile; study group). The main outcome measure was rate of preeclampsia.

RESULTS

Of 6,887 women screened, 3,830 were available for analysis and 167 were excluded due to potential confounders. Of the remaining 3,663 women enrolled, 357 women were categorised as having low PAPP-A levels and 3,306 had normal PAPP-A levels. The prevalence of preeclampsia (8.4% vs. 2.6%) and early-onset preeclampsia (i.e. before 34 weeks of gestation) (1.1% vs. 0.1%) was significantly higher (relative risk 3.27 and 9.26, respectively) in women from the study group than in the control group.

CONCLUSION

Pregnancy with PAPP-A levels < 10th percentile was significantly associated with an increased risk of preeclampsia that tended toward early development. Therefore, pregnant women with low PAPP-A levels in the first trimester should be considered to be at increased risk of preeclampsia.

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.

A best practice position statement on pregnancy in chronic kidney disease: the Italian Study Group on Kidney and Pregnancy

Pregnancy is increasingly undertaken in patients with chronic kidney disease (CKD) and, conversely, CKD is increasingly diagnosed in pregnancy: up to 3 % of pregnancies are estimated to be complicated by CKD. The heterogeneity of CKD (accounting for stage, hypertension and proteinuria) and the rarity of several kidney diseases make risk assessment difficult and therapeutic strategies are often based upon scattered experiences and small series. In this setting, the aim of this position statement of the Kidney and Pregnancy Study Group of the Italian Society of Nephrology is to review the literature, and discuss the experience in the clinical management of CKD in pregnancy. CKD is associated with an increased risk for adverse pregnancy-related outcomes since its early stage, also in the absence of hypertension and proteinuria, thus supporting the need for a multidisciplinary follow-up in all CKD patients. CKD stage, hypertension and proteinuria are interrelated, but they are also independent risk factors for adverse pregnancy-related outcomes. Among the different kidney diseases, patients with glomerulonephritis and immunologic diseases are at higher risk of developing or increasing proteinuria and hypertension, a picture often difficult to differentiate from preeclampsia. The risk is higher in active immunologic diseases, and in those cases that are detected or flare up during pregnancy. Referral to tertiary care centres for multidisciplinary follow-up and tailored approaches are warranted. The risk of maternal death is, almost exclusively, reported in systemic lupus erythematosus and vasculitis, which share with diabetic nephropathy an increased risk for perinatal death of the babies. Conversely, patients with kidney malformation, autosomal-dominant polycystic kidney disease, stone disease, and previous upper urinary tract infections are at higher risk for urinary tract infections, in turn associated with prematurity. No risk for malformations other than those related to familiar urinary tract malformations is reported in CKD patients, with the possible exception of diabetic nephropathy. Risks of worsening of the renal function are differently reported, but are higher in advanced CKD. Strict follow-up is needed, also to identify the best balance between maternal and foetal risks. The need for further multicentre studies is underlined.

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.

Is It Possible to Differentiate Chronic Kidney Disease and Preeclampsia by means of New and Old Biomarkers? A Prospective Study

Objective. Chronic kidney disease (CKD) and preeclampsia (PE) may both present with hypertension and proteinuria in pregnancy. Our objective is to test the possibility of distinguishing CKD from PE by means of uteroplacental flows and maternal circulating sFlt-1/PlGF ratio. Design. Prospective analysis. Population. Seventy-six patients (35 CKD, 24 PE, and 17 other hypertensive disorders), with at least one sFlt-1/PlGF and Doppler evaluation after the 20th gestational week. Methods. Maternal sFlt-1-PlGF were determined by immunoassays. Abnormal uterine artery Doppler was defined as resistance index ≥ 0.58. Umbilical Doppler was defined with gestational-age-adjusted Pulsatility Index. Clinical diagnosis was considered as reference. Performance of Doppler study was assessed by sensitivity analysis; sFlt-1/PlGF cut-off values were determined by ROC curves. Results. The lowest sFlt-1/PlGF ratio (8.29) was detected in CKD, the highest in PE (317.32) (P < 0.001). Uteroplacental flows were mostly preserved in CKD patients in contrast to PE (P < 0.001). ROC analysis suggested two cut-points: sFlt-1/PlGF ≥ 32.81 (sensitivity 82.93%; specificity 91.43%) and sFlt-1/PlGF ≥ 78.75 (sensitivity 62.89%, specificity 97.14%). Specificity reached 100% at sFlt-1/PlGF ≥ 142.21 (sensitivity: 48.8%). Early-preterm delivery was associated with higher sFlt-1/PlGF ratio and abnormal uteroplacental flows relative to late-preterm and term deliveries. Conclusions. sFlt-1/PlGF ratio and uteroplacental flows significantly correlated with PE or CKD and preterm delivery.

Serum HtrA1 is differentially regulated between early-onset and late-onset preeclampsia

INTRODUCTION

HtrA1 (high temperature requirement A1) is a serine protease of the HtrA family. We have previously shown that the placenta expresses the highest level of HtrA1 mRNA compared to other tissues in the human. Others have reported that placental HtrA1 is significantly up-regulated in preeclampsia (PE), a pregnancy-specific multi-systemic disorder associated with new onset hypertension and proteinuria. However, it is unclear how serum HtrA1 changes in a normal pregnancy and whether it is altered in PE pregnancies.

METHODS

A sandwich ELISA highly specific to human HtrA1 and suitable for serum detection was developed and thoroughly validated. This assay was then applied to serum samples from different stages of normal pregnancy, as well as early-onset (<34 weeks) and late-onset (>34 weeks) PE pregnancies.

RESULTS

Serum HtrA1 increased progressively with increasing gestation in normal pregnancies. However, this trend was perturbed in women with PE. Compared to respective gestation-age-matched normal pregnancies, HtrA1 serum levels were significantly increased in early-onset PE, but significantly reduced in late-onset PE.

DISCUSSION

This is the first report to show a clear increase of HtrA1 in the maternal circulation during normal pregnancy, consistent with HtrA1 being highly expressed in the placenta. Importantly, this study identified that serum HtrA1 was altered differently in early-onset and late-onset PE pregnancies, highlighting the complex regulation of HtrA1 in the different subtypes. The significant increase of serum HtrA1 in early-onset PE suggests that it may be a potential biomarker for the diagnosis of early-onset PE at disease presentation.

Hypothesis: Pentoxifylline explores new horizons in treatment of preeclampsia

Preeclampsia, the leading cause of maternal morbidity and perinatal mortality, initiates as inappropriate immune response to trophoblastic invasion impairs placentation and placental circulation. A poorly perfused placenta generates superoxide anions as well as anti-angiogenic factors and this series of events result in impairment of endothelial function, followed by maternal morbidities such as hypertension, kidney injury and proteinuria. Renal loss of anti-coagulant proteins and subsequent hyper-coagulable state along with endothelial dysfunction accelerates progression of the disease toward eclampsia. Since Pentoxifylline, a methyl-xanthine derivative known for enhancement of vascular endothelial function, down-regulation of many inflammatory cytokines increased during preeclampsia, improvement of placental circulation, reduction of ischemia-reperfusion injury, enhancement of vasodilatation and endothelial function, ameliorating proteinuria, inhibition of platelet aggregation and decreasing risk of preterm labor, which are all amongst morbidities of preeclampsia, here it is hypothesized that Pentoxifylline prevents development of preeclampsia and/or decelerate progression of the disease.

Circulating Levels of sFlt1 Splice Variants as Predictive Markers for the Development of Preeclampsia

Angiogenic biomarkers, including soluble fms-like tyrosine kinase 1 (sFlt1), are thought to be predictors of preeclampsia onset; however, improvement is needed before a widespread diagnostic test can be utilized. Here we describe the development and use of diagnostic monoclonal antibodies specific to the two main splice variants of sFlt1, sFlt1-1 and sFlt1-14. These antibodies were selected for their sensitivity and specificity to their respective sFlt1 isoform in a capture ELISA format. Data from this pilot study suggest that sFlt1-1 may be more predictive of preeclampsia than total sFlt1. It may be possible to improve current diagnostic platforms if more specific antibodies are utilized.

Correlation between cell-free mRNA expressions and PLGF protein level in severe preeclampsia

BACKGROUND

Preeclampsia is a major cause of morbidity and mortality, both maternal and perinatal. The etiology and pathophysiology of preeclampsia remain unknown. Research shows the implantation of the placenta in preeclampsia occurs due to incomplete angiogenic imbalance as one of the preeclampsia pathogenesis. PlGF is angiogenic protein which is synthesized in placenta by mRNA PlGF. When damage occurs, mRNA will be released from cell and form cell-free mRNA. This study aims to analyze the differences between the PlGF mRNA expression in severe preeclampsia and normal pregnancy as well as to measure the relationship between cell-free mRNA and levels of PlGF with the incidence of severe preeclampsia.

METHODS

The method used in this study is an observational analytic study with cross-sectional design. Blood samples were obtained from patients with preeclampsia and normal pregnancies as the controlling factors in accordance with inclusion and exclusion criterias. Examination of the PlGF level was measured by ELISA method and mRNA PIGF expression was measured by RT-PCR. Physical and laboratory examinations of patients were recorded and collected as data. Calculations were done by statistical analysis.

RESULTS

Mean of the cell-free mRNA PlGF expression level in severe preeclampsia is 2.2983 ng/mL within the scale of 1.96-2.83 ng/mL and deviation standard of 0.1897. Using Pearson Analysis Test, the result shows that there is a positive correlation between cell-free mRNA expression and PlGF protein level in severe preeclampsia, with r = 0.640 dan p < 0.004.

CONCLUSION

There is no difference between expression of cell-free mRNA PlGF in severe preeclampsia serum and normal pregnancy. There is a significant correlation between expression of cell-free mRNA and PlGF protein level in severe preeclampsia.

Is the imbalance between pro-angiogenic and anti-angiogenic factors associated with preeclampsia?

BACKGROUND

Preeclampsia (PE) is a multisystem disease characterized by the development of hypertension and proteinuria. Although PE etiology is not fully known, the placenta seems to play a central role in the development of disease. The inadequate placentation process results in a change in angiogenic factors levels, such as vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble form of endoglin (s-Eng) and soluble form of vascular endothelial growth factor receptor type 1 (sFlt-1).

OBJECTIVE

The aim of this review was to clarify if the imbalance between pro-angiogenic and anti-angiogenic factors is associated with PE.

CONCLUSION

It is known that inadequate placentation process is the primary mechanism suggested for PE occurrence and angiogenic factors are involved in this process. The state-of-the-art suggests that progress in grasp the imbalance of pro-angiogenic and anti-angiogenic factors is essential for the improvement of knowledge about PE. The development of prospective, longitudinal studies with serial determinations of these factors throughout pregnancy is needed to better assess the relevance of these markers for understanding the etiology, prevention, diagnosis, prognosis and treatment of this challenging disease.

Urine proteomic studies in preeclampsia

Preeclampsia (PE) is a multisystem disorder of pregnancy that develops after 20 wk of gestation in previously normotensive women and complicates 5-8% of pregnancies. This rapidly progressive syndrome is usually diagnosed when the mother develops hypertension and proteinuria. The only effective treatment is delivery of the baby although early low-dose aspirin has been shown to significantly reduce the risk for PE. Recent advances in proteomic methods of protein separation, identification, and quantitation may allow for the identification of proteins and peptides that could facilitate early detection of disease, improve assessment of prognosis, and allow closer monitoring of women at risk for PE. This review summarizes all currently available markers for prediction and diagnosis of PE and presents urine proteomic studies performed for the identification of novel biomarkers.

NK cell abnormality and its treatment in women with reproductive failures such as recurrent pregnancy loss, implantation failures, preeclampsia, and pelvic endometriosis

The regulation of uterine and peripheral blood natural killer (NK) cells has been associated with problems related to reproductive immunology such as recurrent pregnancy loss (RPL), implantation failure or preeclampsia. NKp46, one of the natural cytotoxicity receptors (NCRs), is a unique marker that functions in NK cell cytotoxicity and cytokine production. Expression of NKp46 on NK cells is lower in women with recurrent pregnancy loss and pregnancy-induced hypertension. Moreover, expression of NKp46 on peritoneal fluid NK cells is lower in women with pelvic endometriosis. Therefore, evaluation of NKp46 on peripheral blood NK cells may provide a means of screening for reproductive abnormalities. Recently, a new type of NK cell, the NK22 cell, has been reported. This cell may be a regulator not only of the mucosal barrier but also of reproduction. For women with RPL showing abnormal uterine and/or peripheral blood NK cells, both intravenous immunoglobulin treatment and intralipid treatment have been reported. The effects of these treatments are still controversial, and further studies are needed in order to clarify their true impact. The present review examines variations in the expression of NCRs on NK cells, the participation of NK22 cells in reproduction, and the possible use of intravenous immunoglobulin or intralipid treatment for women with recurrent pregnancy loss and NK cell abnormality.

Diagnostic accuracy of the soluble Fms-like tyrosine kinase-1/placental growth factor ratio for preeclampsia: a meta-analysis based on 20 studies

PURPOSE

To investigate the accuracy of the soluble fms-like tyrosine kinase-1(sFlt-1)/placental growth factor (PlGF) ratio to predict preeclampsia (PE).

METHODS

A search in the PubMed, Embase, and Cochrane Library was conducted for human studies without language restriction. We included the studies reported sufficient data to reconstruct the diagnostic 2 × 2 table of sFlt-1/PlGF with testing of PlGF and sFlt-1 in serum or plasma. Two reviewers independently screened the articles. Disagreements were resolved by a third reviewer. Unpublished data were requested from the authors of the study by email.

RESULTS

Twenty studies with 28 groups of women with different gestational ages were included in our study. The pooled diagnostic sensitivity and specificity of sFlt-1/PlGF were 0.78 and 0.84 with the area under the SROC curve (AUC) of 0.88. In subgroup analyses, the diagnostic value of sFlt-1/PlGF for early-onset PE is highest with a pooled diagnostic odds ratio (DOR) of 241 and AUC of 0.98.

CONCLUSIONS

The accuracy of sFlt-1/PlGF ratio for screening PE was moderate and was high for early-onset PE. High-quality studies are needed to confirm their usefulness in prediction of PE in clinical practice.

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

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

Low molecular weight heparin therapy during pregnancy is associated with elevated circulatory levels of placental growth factor

INTRODUCTION

Low molecular weight heparin (LMWH) has been shown to be effective in decreasing the recurrence of placenta-mediated complications of pregnant women. The aim of this study was to determine the effect of LMWH on circulating levels of soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng) and placental growth factor (PLGF) in pregnant women who required anticoagulation therapy.

METHODS

A longitudinal prospective cohort study was performed including pregnant women in whom anticoagulation therapy by LMWH during pregnancy was clinically indicated (n = 33). Healthy pregnant women, matched for gestational age, who did not require thromboprophylaxis served as controls (n = 29). Maternal plasma samples were obtained throughout gestation every 4 weeks and stored at -70 °C. Maternal plasma concentrations of sFlt-1, sEng and PLGF were determined by ELISA and compared between the two groups.

RESULTS

Patients treated with LMWH had significantly increased circulatory levels of PLGF during the third trimester compared with controls (28-34 weeks: 719.2 pg/ml vs 558.6 pg/ml at, p < 0.01; 35-40 weeks: 975.6 pg/ml vs 511.2 pg/ml, p < 0.01, respectively). In contrast, circulatory levels of sFlt-1 and sEng were similar between the LMWH treatment group and controls throughout gestation. Consistent with these findings, the ratio of sFlt-1/PLGF was lower in patients treated with LMWH compared to controls (28-34 weeks: 1.9 vs 7.2, p < 0.05; 35-40 weeks: 5 vs 12.9, p < 0.05, respectively).

DISCUSSION

Anticoagulation treatment of pregnant women with LMWH is associated with a pro-angiogenic state. These findings may explain the effectiveness of LMWH in the prevention of placenta-mediated complications of pregnancy.

Placental Nkx2-5 and target gene expression in early-onset and severe preeclampsia

OBJECTIVE

Preeclampsia (PE) affects 2-8% of pregnancies worldwide and is a significant source of maternal and neonatal morbidity and mortality. However, the mechanisms underlying PE are poorly understood and major questions regarding etiology and risk factors remain to be addressed. Our objective was to examine whether abnormal expression of the cardiovascular developmental transcription factor, Nkx2-5, was associated with early onset and severe preeclampsia (EOSPE).

METHODS

Using qPCR and immunohistochemical assay, we examined expression of Nkx2-5 and target gene expression in EOSPE and control placental tissue. We tested resulting mechanistic hypotheses in cultured cells using shRNA knockdown, qPCR, and western blot.

RESULTS

Nkx2-5 is highly expressed in racially disparate fashion (Caucasians > African Americans) in a subset of early EOSPE placentae. Nkx2-5 mRNA expression is highly correlated (Caucasians > African Americans) to mRNA expression of the preeclampsia marker sFlt-1, and of the Nkx2-5 target and RNA splicing factor, Sam68. Knockdown of Sam68 expression in cultured cells significantly impacts sFlt-1 mRNA isoform generation in vitro, supporting a mechanistic hypothesis that Nkx2-5 impacts EOSPE severity in a subset of patients via upregulation of Sam68 to increase sFlt-1 expression. Expression of additional Nkx2-5 targets potentially regulating metabolic stress response is also elevated in a racially disparate fashion in EOSPE.

CONCLUSIONS

Expression of Nkx2-5 and its target genes may directly influence the genesis and racially disparate severity, and define a mechanistically distinct subclass of EOSPE.

Pre-eclampsia part 2: prediction, prevention and management

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

Prediction of preeclampsia and induced delivery at <34 weeks gestation by sFLT-1 and PlGF in patients with abnormal midtrimester uterine Doppler velocimetry: a prospective cohort analysis

Background

Women with bilateral abnormal uterine artery Doppler velocimetry (UtADV) are at increased risk for an adverse pregnancy outcome. This study aimed to determine if additional assessment of midtrimester angiogenic factors improves the predictive accuracy of Doppler results for various outcome parameters.

Methods

Women with a bilateral abnormal UtADV, which was defined as a postsystolic incision and/or an increased pulsatility index greater than the 95^th centile, and a singleton pregnancy were prospectively recruited between 19 + 0 and 26 + 6 weeks of gestation. Maternal serum levels of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFLT-1) were measured with a fully automated immunoassay and their ratio was calculated.

Results

Angiogenic factors could predict the development of preeclampsia (PE), as well as induced delivery at <34 weeks of gestation, but failed to predict the development of normotensive intrauterine growth restriction. Twelve (24.0%) of the 50 recruited women developed PE. Nine of these patients had early-onset disease (<34 + 0 weeks). Six (12.0%) patients were delivered at <34 + 0 weeks. The most useful test results in the prediction of PE and induced delivery at <34 + 0 weeks were observed using the sFLT-1/PlGF >95^th centile ratio with a sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of 66.7%, 89.5%, 66.7%, and 89.5% for PE, and 85.7%, 86.1%, 50.1%, and 97.4% for induced delivery, respectively. Positive and negative likelihood ratios were 6.33 (95% CI 2.31–17.38) and 0.37 (95% CI 0.17–0.84) for PE, and 6.14 (95% CI 2.76–13.69) and 0.17 (0.03–1.02) for induced delivery, respectively. Corresponding odds ratios were 17.0 (95% CI 3.5–83.0) and 37.0 (95% CI 3.8–363.9), respectively.

Conclusions

Measurement of angiogenic factors improves the specificity of an abnormal UtADV for prediction of PE. Compared with prediction of PE an abnormal sFLT-1/PlGF ratio revealed higher sensitivity for prediction of induced delivery at <34 + 0 weeks. The NPV of 97% will help to reassure most patients with an abnormal UtADV and a normal sFLT-1/PlGF ratio.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2393-14-292) contains supplementary material, which is available to authorized users.