Short-term prediction of preeclampsia using the sFlt-1/PlGF ratio: a subanalysis of pregnant Japanese women from the PROGNOSIS Asia study

Maternal angiogenic factor disruptions prior to clinical diagnosis of preeclampsia: insights from the REVAMP study

Preeclampsia is characterized by impaired angiogenesis and assessment of angiogenic factors can play a crucial role in the early diagnosis of preeclampsia. The current study reports the levels of angiogenic factors longitudinally from early pregnancy in women with preeclampsia and in the subtypes of preeclampsia, to identify their role in early prediction of preeclampsia. A total of 1154 women with singleton pregnancies were recruited in early pregnancy from 2 hospitals. Blood samples were collected, plasma samples were separated and stored at four time points across gestation: V1 = 11-14 weeks, V2 = 18-22 weeks, V3 = 26-28 weeks, and V4 = at delivery. The current study includes a total of 108 women developed preeclampsia (PE), and 216 matched controls. Angiogenic factors were estimated using commercially available ELISA kits. Receiver operating characteristic (ROC) curves were used to evaluate the potential diagnostic value in the prediction of PE. Lower levels of VEGF, PlGF, and higher levels of sEng and sEng/PlGF ratio (p < 0.05 for all) predate clinical diagnosis in women with preeclampsia. sEng levels and sEng/PlGF ratio showed significant correlation with odds of preeclampsia at all the timepoints. This study identifies a cut off of 33.5 for sFlt-1/PlGF and 25.9 for sEng/PlGF for prediction of early onset preeclampsia. This study reports various angiogenic factors serially across gestation in a general population to identify women at risk of developing preeclampsia and its subtypes. The study also reports a potential biomarker and a pragmatic window for estimation of angiogenic markers to identify women at risk.

sFlt1/PlGF among patients with suspected preeclampsia when considering hypertensive status

BACKGROUND

In high-resource settings, biomarkers of angiogenic balance, such as the soluble fms-like tyrosine kinase-1 (sFlt1)/placental growth factor (PlGF) ratio, have been studied extensively to aid in evaluation of patients with suspected preeclampsia (PE), and have been incorporated into the 2021 International Society for the Study of Hypertension in Pregnancy definition of PE. The utility in under-resourced settings has not been as well characterized.

OBJECTIVE

This analysis sought to identify the role of the sFlt1/PlGF ratio in the evaluation of patients with or without hypertension who are suspected of having PE without other diagnostic information.

STUDY DESIGN

This is a secondary analysis of a prior prospective study of patients who were presented with suspected PE at ≥20+0 weeks' gestation at a single academic tertiary care center. Patients were recruited in the parent study from July 2009 to June 2012. In the original study, clinicians were masked to biomarker results, and patients were followed by chart review. In this analysis, the performance of the sFlt1/PlGF ratio (≤38, >38, or >85) was assessed alone in identifying both hypertensive and non-hypertensive patients at risk of evolving into PE with severe features (PE-SF; American College of Obstetricians and Gynecologists' definition) within two weeks of the triage visit (PE-SF2). Hypertension was defined as a blood pressure (BP)≥140/90 mmHg.

RESULTS

There were 1043 patients included in the analysis; of whom, 579 (55.5%) and 464 (44.5%) presented with or without hypertension, respectively. In triage, 332 (75.4%) of hypertensive patients presented due to BP concerns, and the remainder were evaluated due to other features (new-onset headache, proteinuria, or edema). On triage evaluation, 66.8% of all patients had a normal sFlt1/PlGF ratio ≤38, and 17.0% had an elevated ratio >85. Among hypertensive patients, a sFlt1/PlGF ratio ≤38 was a good rule-out test for PE-SF2 (negative likelihood ratio [LR-] of 0.15), and a ratio >85 was a good rule-in test (positive likelihood ratio [LR+] of 5.75). Among normotensive patients, sFlt1/PlGF was useful as a rule-in test for ratio >38 (LR+ 5.13) and >85 (LR+ 12.80). Stratified by gestational age, sFlt1/PlGF continued to be a good rule in and good rule out test at <35 weeks among those with hypertension but did not have good test performance ≥35 weeks. sFlt1/PlGF had a good test performance as a rule in test for >85 regardless of gestational age. In triage, 4.3% (30/693) of patients with sFlt1/PlGF ratio <38 had concurrent laboratory evidence of PE, compared with 15.9% (28/176) patients with ratio >85.

CONCLUSION

These findings support the potential for the use of sFlt1/PlGF and BP measurement alone in resource-limited settings where other laboratory tests or clinical expertise are unavailable for risk stratification. Performance of the biomarker varied by the presence of hypertension and gestational age.

Statins Prevent the Deleterious Consequences of Placental Chemerin Upregulation in Preeclampsia

BACKGROUND

Chemerin, an inflammatory adipokine, is upregulated in preeclampsia, and its placental overexpression results in preeclampsia-like symptoms in mice. Statins may lower chemerin.

METHODS

Chemerin was determined in a prospective cohort study in women suspected of preeclampsia and evaluated as a predictor versus the sFlt-1 (soluble fms-like tyrosine kinase-1)/PlGF (placental growth factor) ratio. Chemerin release was studied in perfused placentas and placental explants with or without the statins pravastatin and fluvastatin. We also addressed statin placental passage and the effects of chemerin in chorionic plate arteries.

RESULTS

Serum chemerin was elevated in women with preeclampsia, and its addition to a predictive model yielded significant effects on top of the sFlt-1/PlGF ratio to predict preeclampsia and its fetal complications. Perfused placentas and explants of preeclamptic women released more chemerin and sFlt-1 and less PlGF than those of healthy pregnant women. Statins reversed this. Both statins entered the fetal compartment, and the fetal/maternal concentration ratio of pravastatin was twice that of fluvastatin. Chemerin constricted plate arteries, and this was blocked by a chemerin receptor antagonist and pravastatin. Chemerin did not potentiate endothelin-1 in chorionic plate arteries. In explants, statins upregulated low-density lipoprotein receptor expression, which relies on the same transcription factor as chemerin, and NO release.

CONCLUSIONS

Chemerin is a biomarker for preeclampsia, and statins both prevent its placental upregulation and effects, in an NO and low-density lipoprotein receptor-dependent manner. Combined with their capacity to improve the sFlt-1/PlGF ratio, this offers an attractive mechanism by which statins may prevent or treat preeclampsia.

Advances in preeclampsia testing

Preeclampsia is a multisystem hypertensive disorder and one of the leading causes of maternal and fetal morbidity and mortality. The clinical hallmarks such as hypertension and proteinuria, and additional laboratory tests currently available including liver enzyme testing, are neither specific nor sufficiently sensitive. Therefore, biomarkers for timely and accurate identification of patients at risk of developing preeclampsia are extremely valuable to improve patient outcomes and safety. In this chapter, we will first discuss the clinical characteristics of preeclampsia and current evidence of the role of angiogenic factors, such as placental growth factor (PlGF) and soluble FMS like tyrosine kinase 1 (sFlt-1) in the pathogenesis of preeclampsia. Second, we will review the clinical practice guidelines for preeclampsia diagnostic criteria and their recommendations on laboratory testing. Third, we will review the currently available PlGF and sFlt-1 assays in terms of their methodologies, analytical performance, and clinical diagnostic values. Finally, we will discuss the future research needs from both an analytical and clinical perspective.

What Is the Correlation between Preeclampsia and Cancer? The Important Role of Tachykinins and Transition Metal Ions

Metal ions are irreplaceable in many biological processes. They are components of numerous metalloproteins and serve as cofactors or structural elements for enzymes. Interestingly, iron, copper and zinc play important roles in accelerating or preventing neoplastic cell transformation. Noteworthily, a lot of proliferative and invasive mechanisms are exploited by both malignant tumors and pregnancy. Cancer cells, as well as developing placenta cells, create a microenvironment supportive of immunologic privilege and angiogenesis. Therefore, pregnancy and cancer progression share many similarities. Moreover, during preeclampsia and cancer, significant changes in relevant trace element concentrations, tachykinin levels, expressions of neurokinin receptors, oxidative stress and angiogenic imbalance are observed. This sheds a new light on the role of metal ions and tachykinins in cancer progression and pregnancy, especially in preeclamptic women.

Blood biomarkers to predict the onset of pre-eclampsia: A systematic review and meta-analysis

Pre-eclampsia is one of the most common pregnancy complications, and a major cause of fetal and maternal morbidity and mortality globally. Diagnosis currently takes place in the third trimester based on clinical symptoms. This systematic review and meta-analysis sought to determine the blood biomarkers that are associated with pre-eclampsia, and in particular, the biomarkers that could predict pre-eclampsia in early pregnancy. We searched the electronic databases (Medline, Embase, Cochrane Library) from inception up to March 2022. Prospective studies with 1000 or more participants that measured blood biomarkers to predict or diagnose pre-eclampsia have been included in this systematic review. Biomarkers' measurements were considered from the first up to the third trimester, but not during labor. Data concerning pre-eclampsia, biomarker measurements and study characteristics were extracted. Meta-analysis was performed when possible. We found a total of 43 studies (assessing 62 different biomarkers in 18,170 pregnancies, have been included in this systematic review, and a total of 6 studies (assessing 2 biomarkers have been included in the meta-analysis). Statistical analysis was performed for PlGF and sFlt-1. Mean difference in PlGF levels between pre-eclampsia and healthy pregnancies, appear to increase as the pregnancy progresses. Results of sFlt-1 meta-analysis were inconclusive. No significant publication bias was identified. This is the most comprehensive and up to date systematic review and meta-analysis on this important topic on blood biomarkers for the early prediction of pre-eclampsia. Further This research highlights the urgent needed for further discovery research to identify blood biomarkers that could predict the development of pre-eclampsia.

Role of microRNAs in trophoblast invasion and spiral artery remodeling: Implications for preeclampsia

It is now well-established that microRNAs (miRNAs) are important regulators of gene expression. The role of miRNAs in placental development and trophoblast function is constantly expanding. Trophoblast invasion and their ability to remodel uterine spiral arteries are essential for proper placental development and successful pregnancy outcome. Many miRNAs are reported to be dysregulated in pregnancy complications, especially preeclampsia and they exert various regulatory effects on trophoblasts. In this review, we provide a brief overview of miRNA biogenesis and their mechanism of action, as well as of trophoblasts differentiation, invasion and spiral artery remodeling. We then discuss the role of miRNAs in trophoblasts invasion and spiral artery remodeling, focusing on miRNAs that have been thoroughly investigated, especially using multiple model systems. We also discuss the potential role of miRNAs in the pathogenesis of preeclampsia.

Efficiency of sFlt-1/PlGF Ratio in Preeclampsia Diagnosis

Background and Objectives: Preeclampsia is a health issue characterized by a new onset of hypertension after 20 weeks of gestation and proteinuria. This is a multiple organ disorder and is associated with significant maternal and fetal mortality. Material and Methods: The study is a prospective one and included 69 pregnant women (17 with hypertension without criteria for PE, 26 with severe PE and 26 with moderate PE) with an age of gestation between 24 and 40 weeks. Subjects were chosen from those who referred to the Oradea County Emergency Clinical Hospital, Department of Obstetrics-Gynecology between January 2020 and December 2022. We collected other characteristics from observation sheets and from patients and we measured the sFlt-1/PlGF ratio after 20 weeks of pregnancy if patients presented with suspected preeclampsia. All the results were collected in Excel analysis by SPSS. Results: In our study, 37.68% had severe preeclampsia, the same percentage had moderate PE and 24.63% presented only with hypertension. The mean of sFLT-1/PlGF for severe preeclampsia was 78.282 ng/mL, and for moderate, it was 50.154 ng/mL. For those who did not have criteria for preeclampsia, it was 29.076 ng/mL. When we compared the values of sFLT-1/PlGF in moderate PE and hypertension, we found that there was a statistically significant difference between this two, and the same conclusion was also obtained for severe PE and hypertension and for severe and moderate PE. Conclusions: This marker can be useful for improving the outcomes for pregnant women with preeclampsia. In addition, for newborns, sFlt-1/PlGF can be helpful because we can correctly and promptly manage a patient affected by this disease before 34 weeks of pregnancy. Our study demonstrates that the correlation between the values of sFlt-1/PlGF and the type of preeclampsia are positive; thus, if the values are high, the pregnant woman likely will develop severe preeclampsia with early onset. In addition, the sFlt-1/PlGF ratio has the highest accuracy for differentiating PE patients from pregnant women who did not develop sign and symptoms for preeclampsia. Our results are in line with the conclusions of other studies that researched the association between sFlt-1/PlGF and clinical diagnosis of preeclampsia.

Update on Hypertension Research in 2021

In 2021, 217 excellent manuscripts were published in Hypertension Research. Editorial teams greatly appreciate the authors' contribution to hypertension research progress. Here, our editorial members have summarized twelve topics from published work and discussed current topics in depth. We hope you enjoy our special feature, "Update on Hypertension Research in 2021".

Cost-effectiveness analysis of implementing screening on preterm pre-eclampsia at first trimester of pregnancy in Germany and Switzerland

Objective

To assess the cost-effectiveness of preterm preeclampsia (PE) screening versus routine screening based on maternal characteristics in Germany and Switzerland.

Methods

A health economic model was used to analyse the cost-effectiveness of PE screening versus routine screening based on maternal characteristics. The analysis was conducted from the healthcare perspective with a time horizon of one year from the start of pregnancy. The main outcome measures were incremental health care costs and incremental costs per PE case averted.

Results

The incremental health care costs for PE screening versus routine screening per woman were €14 in Germany, and -CHF42 in Switzerland, the latter representing cost savings. In Germany, the incremental costs per PE case averted were €3,795. In Switzerland, PE screening was dominant. The most influential parameter in the one-way sensitivity analysis was the cost of PE screening (Germany) and the probability of preterm PE in routine screening (Switzerland). In Germany, at a willingness-to-pay for one PE case avoided of €4,200, PE screening had a probability of more than 50% of being cost-effective compared to routine screening. In Switzerland, at a willingness-to-pay of CHF0, PE screening had a 78% probability of being the most cost-effective screening strategy.

Conclusion

For Switzerland, PE screening is expected to be cost saving in comparison to routine screening. For Germany, the additional health care costs per woman were expected to be €14. Future cost-effectiveness studies should be conducted with a longer time horizon.

Study on lipid nanomicelles targeting placenta for the treatment of preeclampsia

In view of the serious clinical harm of preeclampsia and the lack of effective treatment methods, a PEG-modified lipid hybrid micelle was designed with folic acid molecule on the surface, containing siRNA, targeted delivery to the placenta, interfering the expression of sFlt-1 and treating preeclampsia. In this paper, the preparation and characterization of lipid hybrid micelles were investigated in detail, the cytology in vitro and in vivo distribution, pharmacodynamics, safety and action mechanism of the preparation were studied, which laid a foundation for gene therapy of preeclampsia.

The feasibility of soluble Fms-Like Tyrosine kinase-1 (sFLT-1) and Placental Growth Factor (PlGF) ratio biomarker in predicting preeclampsia and adverse pregnancy outcomes among medium to high risk mothers in Kuala Lumpur, Malaysia

Background

Preeclampsia significantly contributes to maternal and perinatal morbidity and mortality. It is imperative to identify women at risk of developing preeclampsia in the effort to prevent adverse pregnancy outcomes through early intervention. Soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) level changes are noticeable several weeks before the onset of preeclampsia and its related complications. This study evaluated the feasibility of the sFlt-1/PlGF biomarker ratio in predicting preeclampsia and adverse pregnancy outcomes using a single cut-off point of >38.

Methods

This is a prospective cohort study conducted at a single tertiary centre, in an urban setting in Kuala Lumpur, Malaysia, between December 2019 and April 2021. A total of 140 medium to high risk mothers with singleton pregnancies were recruited at ≥20 weeks’ gestation. sFlt-1/PlGF ratio was measured and the participant monitored according to a research algorithm until delivery. The primary outcome measure was incidence of preeclampsia and the secondary outcome measure was incidence of other adverse pregnancy outcomes.

Results

The overall incidence of preeclampsia was 20.7% (29/140). The mean sFlt-1/PlGF ratio was significantly higher in preeclampsia (73.58 ± 93.49) compared to no preeclampsia (13.41 ± 21.63) (p = 0.002). The risk of preeclampsia (adjusted OR 28.996; 95% CI 7.920–106.164; p<0.001) and low Apgar score (adjusted OR 17.387; 95% CI 3.069–98.517; p = 0.028) were significantly higher among women with sFlt-1/PlGF ratio >38 compared with sFLT-1/PlGF ratio ≤38. The area under the receiver-operator characteristic curve (AUC) for a combined approach (maternal clinical characteristics and biomarker) was 86.9% (p<0.001, 95% CI 78.7–95.0) compared with AUC biomarker alone, which was 74.8% (p<0.001, 95% CI 63.3–86.3) in predicting preeclampsia. The test sensitivity(SEN) was 58.6%, specificity (SPEC) 91%,positive predictive value (PPV) 63% and negative predictive value (NPV) 89.3% for prediction of preeclampsia. For predicting a low Apgar score at 5 minutes, the SEN was 84.6%, SPEC 87.4%, PPV 40.7%, and NPV 98.2%; low birth weight with SEN 52.6%,SPEC 86.0%, PPV 37.0%, NPV 92.0%; premature delivery with SEN 48.5%, SPEC 89.5%, PPV 59.3%, NPV 84.7% and NICU admission with SEN 50.0%, SPEC 85.8%, PPV 37.0% and NPV 91.2%.

Conclusions

It is feasible to use single cut-off point of >38 ratio of the biomarkers sFlt-1/PlGF in combination with other parameters (maternal clinical characteristics) in predicting preeclampsia and adverse pregnancy outcomes among medium to high risk mothers without restricting outcome measurement period to 1 and 4 weeks in a single urban tertiary centre in Kuala Lumpur, Malaysia.

Reduced expression in preterm birth of sFLT-1 and PlGF with a high sFLT-1/PlGF ratio in extracellular vesicles suggests a potential biomarker

Preterm birth may have a pathological impact on intrauterine development of the fetal brain, resulting in developmental disabilities. In this study, we examine the expression of soluble Fms-like tyrosine kinase 1 (sFLT-1) and placental growth factor (PlGF), which is one of the vascular endothelial growth factors (VEGFs), as these play a key role in angiogenesis; in particular, we examine their effect on the sFLT-1/PlGF ratio in cases of preterm birth as compared to typical pregnancies. Enzyme-linked immunosorbent assay was performed on samples of maternal-derived plasma and extracellular vesicles-exosomes (EVs-EXs) isolated at the third trimester, consisting of 17 samples from cases of preterm birth and 38 control cases. Our results showed that both sFLT-1 (P=0.0014) and PlGF (P=0.0032) were significantly downregulated in cases of preterm birth compared to controls, while the sFLT-1/PIGF ratio was significantly (P=0.0008) increased in EVs-EXs, but not in maternal plasma. Our results suggest that this reduced expression of sFLT-1 and PlGF with an elevated sFLT-1/PlGF ratio in EVs-EXs may represent a potential biomarker for prediction of PTB.

Short-Term Prediction of Preeclampsia in Chinese Women Using the Soluble fms-Like Tyrosine Kinase 1/Placental Growth Factor Ratio: A Sub-Analysis of the PROGNOSIS Asia Study

The diagnosis of preeclampsia in China currently relies on limited clinical signs and unspecific laboratory findings. These are inadequate predictors of preeclampsia development, limiting early diagnosis and appropriate management. Previously, the Prediction of Short-Term Outcome in Pregnant Women with Suspected Preeclampsia Study (PROGNOSIS) and PROGNOSIS Asia demonstrated that a soluble fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio of ≤38 can be used to rule out preeclampsia within 1 week, with negative predictive values of 99.3 and 98.6%, respectively. This is an exploratory sub-analysis of the Chinese cohort (n = 225) of the PROGNOSIS Asia study. The primary objectives were to assess the predictive performance of using the sFlt-1/PlGF ratio to rule out preeclampsia within 1 week and to rule in preeclampsia within 4 weeks. The sFlt-1/PlGF ratio was also examined for short-term prediction of fetal adverse outcomes, maternal adverse outcomes, and time to delivery. The overall prevalence of preeclampsia was 17.3%. With the use of an sFlt-1/PlGF ratio of ≤38, the negative predictive value for ruling out preeclampsia within 1 week was 97.3% [95% confidence interval (CI), 93.8-99.1], with a sensitivity of 64.3% and specificity of 85.3%. With the use of an sFlt-1/PlGF ratio of >38, the positive predictive value for ruling in preeclampsia within 4 weeks was 35.0% (95% CI, 20.6-51.7), with a sensitivity of 50.0% and specificity of 86.8%. In the analyses of the sFlt-1/PlGF ratio and fetal adverse outcomes, the area under the receiver operating characteristic curve was 92.8% (95% CI, 83.5-98.7) for ruling out fetal adverse outcomes within 1 week and 79.9% (95% CI, 68.1-90.3) for ruling in fetal adverse outcomes within 4 weeks. An sFlt-1/PlGF ratio of >38 increased the likelihood of imminent delivery 3.3-fold compared with a ratio of ≤38 [hazard ratio, 3.3 (95% CI, 2.1-5.1)]. This sub-analysis confirms the high predictive performance of the sFlt-1/PlGF ratio cutoff of 38 for short-term prediction of preeclampsia in Chinese women, which may help prevent unnecessary hospitalization of women with low risk of developing preeclampsia.

Two cases of pregnancy after achieving complete remission of chronic active Epstein-Barr virus infection

Chronic active Epstein-Barr virus (CAEBV) infection characterized by persistent infectious mononucleosis-like symptoms can lead to cardiovascular diseases. We encountered two pregnant women with CAEBV histories complicated with cardiovascular diseases. A 36-year-old woman with a history of myocardial infarction due to CAEBV and coronary artery bypass grafting became pregnant. Her left ventricular ejection fraction (LVEF) decreased, and cesarean section was performed at 36 weeks of gestation. Her LVEF recovered after delivery. A 32-year-old woman with a history of CAEBV and chronic hypertension was diagnosed with mild pulmonary arterial hypertension (PAH) after conception. She strongly desired to continue the pregnancy. She became complicated with severe superimposed preeclampsia at 31 weeks of gestation, and cesarean section was performed. Her PAH did not deteriorate during pregnancy or the postpartum period. Women treated for CAEBV, even with complete remission, require a preconception evaluation focused on the cardiovascular system and careful management of their pregnancy.

Economic evaluation of the sFlt-1/PlGF ratio for the short-term prediction of preeclampsia in a Japanese cohort of the PROGNOSIS Asia study

The PRediction of short-term Outcomes in preGNant wOmen with Suspected preeclampsIa Study (PROGNOSIS) Asia validated the use of the soluble fms-like tyrosine 1/placental growth factor (sFlt-1/PlGF) ratio cutoff value of ≤38 to rule out the occurrence of preeclampsia in the short term in Asian women. We assessed the economic impact of the introduction of the sFlt-1/PlGF ratio test for predicting preeclampsia in Japan using data from the Japanese cohort of PROGNOSIS Asia. The cost analysis was developed with estimates in either a no-test scenario, with clinical decisions based on standard diagnostic procedures alone, or a test scenario, in which the sFlt-1/PlGF ratio test was used in addition to standard diagnostic procedures. For both scenarios, rates of hospitalization and other test characteristics were obtained from the results for the Japanese cohort in PROGNOSIS Asia. The total cost per patient was the main outcome of this cost analysis model. Introduction of the sFlt-1/PlGF ratio test using a cutoff value of 38 resulted in a reduced hospitalization rate compared with the rate in the no-test scenario (14.4% versus 8.7%). The reduction in the rate of hospitalizations led to an estimated 16 373 JPY reduction in healthcare costs per patient. The sFlt-1/PlGF ratio test is likely to reduce the unnecessary hospitalization of women at low risk of developing preeclampsia in the short term while also identifying high-risk individuals requiring appropriate management. Reducing unnecessary hospitalizations would result in significant cost savings in the Japanese healthcare system.