Urinary placental growth factor in preeclampsia and fetal growth restriction: An alternative to circulating biomarkers?

Efficient isolation of encoded microparticles in a degassed micromold for highly sensitive and multiplex immunoassay with signal amplification

Multiplex detection of low-abundance protein biomarkers in biofluids can contribute to diverse biomedical fields such as early diagnosis and precision medicine. However, conventional techniques such as digital ELISA, microarray, and hydrogel-based assay still face limitations in terms of efficient protein detection due to issues with multiplexing capability, sensitivity, or complicated assay procedures. In this study, we present the degassed micromold-based particle isolation technique for highly sensitive and multiplex immunoassay with enzymatic signal amplification. Using degassing treatment of nanoporous polydimethylsiloxane (PDMS) micromold, the encoded particles are isolated in the mold within 5 min absorbing trapped air bubbles into the mold by air suction capability. Through 10 min of signal amplification in the isolated spaces by fluorogenic substrate and horseradish peroxidase labeled in the particle, the assay signal is amplified with one order of magnitude compared to that of the standard hydrogel-based assay. Using the signal amplification assay, vascular endothelial growth factor (VEGF) and chorionic gonadotropin beta (CG beta), the preeclampsia-related protein biomarkers, are quantitatively detected with a limit of detection (LoD) of 249 fg/mL and 476 fg/mL in phosphate buffer saline. The multiplex immunoassay is conducted to validate negligible non-specific detection signals and robust recovery rates in the multiplex assay. Finally, the VEGF and CG beta in real urine samples are simultaneously and quantitatively detected by the developed assay. Given the high sensitivity, multiplexing capability, and process simplicity, the presented particle isolation-based signal amplification assay holds significant potential in biomedical and proteomic fields.

Urinary sFlt-1 and PlGF as preeclampsia predictors: sFlt-1/creatinine ratio improves the prediction value

OBJECTIVES

To evaluate the correlation between maternal serum and urinary soluble Fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) levels and to assess their potential value in preeclampsia and fetal growth restriction.

STUDY DESIGN

This case-control longitudinal prospective study was performed in 49 singleton pregnant women, divided into two clinical groups, low risk pregnancy (n = 23) and pregnancy complicated by preeclampsia (n = 26). Maternal serum and urinary sFlt-1 and PlGF levels were quantified by electrochemiluminescence. Every patient underwent an ultrasound for fetal biometry. Doppler assessment was done when estimated fetal weight was under the 10th centile. ROC curves were used to evaluate the predictive capability of serum and urinary angiogenic biomarkers and their ratios on preeclampsia. Linear regression was used to compare the values of serum and urinary sFlt-1 and PlGF and their ratios.

RESULTS

Urine biomarkers were positively associated with their serum values, being the best associated urinary PlGF (R2 = 0.73), which also showed the highest predictive capability of preeclampsia of urine biomarkers (AUC 0.866). The predictive capability of urinary sFlt-1 was much lower (AUC 0.640), but increased when adjusting by serum creatinine, a more precise parameter (AUC 0.863).

CONCLUSIONS

Urinary PlGF could be a lesser invasive alternative to circulating biomarkers to monitor pregnancies complicated with preeclampsia that need repeated controls of their pregnancy complication. Urinary sFlt-1 values need adjustment by serum creatinine to be reliable.

Detection of Urinary Misfolded Proteins for Imminent Prediction of Preeclampsia in Pregnant Women With Suspected Cases: Protocol for a Prospective Noninterventional Study

BACKGROUND

Preeclampsia (PE) is one of the most common hypertensive diseases, affecting 2%-8% of all pregnancies. The high maternal and fetal mortality rates of PE are due to a lack of early identification of affected pregnant women that would have led to closer monitoring and care. Recent data suggest that misfolded proteins might be a promising biomarker for PE prediction, which can be detected in urine samples of pregnant women according to their congophilia (aggregated) characteristic.

OBJECTIVE

The main purpose of this trial is to evaluate the value of the urine congophilia-based detection of misfolded proteins for the imminent prediction of PE in women presenting with suspected PE. The secondary objectives are to demonstrate that the presence of urine misfolded proteins correlates with PE-related maternal or neonatal adverse outcomes, and to establish an accurate PE prediction model by combining misfolded proteins with multiple indicators.

METHODS

At least 300 pregnant women with clinical suspicion of PE will be enrolled in this prospective cohort study. Participants should meet the following inclusion criteria in addition to a suspicion of PE: ≥18 years old, gestational week between 20+0 and 33+6, and single pregnancy. Consecutive urine samples will be collected, blinded, and tested for misfolded proteins and other PE-related biomarkers at enrollment and at 4 follow-up visits. Clinical assessments of PE status and related complications for all participants will be performed at regular intervals using strict diagnostic criteria. Investigators and participants will remain blinded to the results. Follow-up will be performed until 42 days postpartum. Data from medical records, including maternal and fetal outcomes, will be collected. The performance of urine misfolded proteins alone and combined with other biomarkers or clinical variables for the prediction of PE will be statistically analyzed.

RESULTS

Enrollment started in July 2023 and was still open upon manuscript submission. As of March 2024, a total of 251 eligible women have been enrolled in the study and enrollment is expected to continue until August 2024. Results analysis is scheduled to start after all participants reach the follow-up endpoint and complete clinical data are collected.

CONCLUSIONS

Upon completion of the study, we expect to derive an accurate PE prediction model, which will allow for proactive management of pregnant women with clinical suspicion of PE and possibly reduce the associated adverse pregnancy outcomes. The additional prognostic value of misfolded proteins is also expected to be confirmed.

TRIAL REGISTRATION

Chinese Clinical Trials Registry ChiCTR2300074878; https://www.chictr.org.cn/showproj.html?proj=202096.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/54026.

Potential urinary biomarkers in preeclampsia: a narrative review

INTRODUCTION

Preeclampsia (PE) is a highly relevant pregnancy-related disorder. An early and accurate diagnosis is crucial to prevent major maternal and neonatal complications and mortality. Due to the association of kidney dysfunction with the pathophysiology of the disease, urine samples have the potential to provide biomarkers for PE prediction, being minimally invasive and easy to perform. Therefore, searching for novel biomarkers may improve outcomes. This narrative review aimed to summarize the scientific literature about the traditional and potential urinary biomarkers in PE and to investigate their applicability to screen and diagnose the disorder.

METHODS

A non-systematic search was performed in PubMed/MEDLINE, Scopus, and SciELO databases.

RESULTS

There is significant divergence in the literature regarding traditionally used serum markers creatinine, cystatin C, and albuminuria, accuracy in PE prediction. As for the potential renal biomarkers investigated, including vascular epithelial growth factor (VEGF), placental growth factor (PlGF), and soluble fms-like tyrosine kinase (sFlt-1), urinary levels of PlGF and sFtl-1/PlGF ratio in urine seem to be the most promising as screening tests. The assessment of the global load of misfolded proteins through urinary congophilia, podocyturia, and nephrinuria has also shown potential for screening and diagnosis. Studies regarding the use of proteomics and metabolomics have shown good accuracy, sensitivity, and specificity for predicting the development and severity of PE.

CONCLUSION

However, there are still many divergences in the literature, which requires future and more conclusive research to confirm the predictive role of urinary biomarkers in pregnant women with PE.

Literature Review: The sFlt1/PlGF Ratio and Pregestational Maternal Comorbidities: New Risk Factors to Predict Pre-Eclampsia

One of the main causes of maternal and neonatal morbidity and mortality is pre-eclampsia. It is characterized by a high sFlt1/PlGF ratio, according to prior research. Pregestational diseases in mothers may increase the risk of developing pre-eclampsia. Only a few studies have looked at the connection between maternal comorbidities before conception and the sFlt1/PlGF ratio. The most recent information regarding the association between maternal pregestational diseases and the ratio of sFlt1/PlGF is described in this review. The paper also examines current research suggesting that changes in pregnancy hormones and metabolites are related to a high sFlt1/PlGF ratio. Certain maternal disorders have been found to dramatically raise sFlt-1 and sFlt1/PlGF levels, according to an analysis of the literature. There is still debate about the data on the association between the sFlt1/PlGF ratio and maternal disorders such as HIV, acute coronary syndromes, cardiovascular function in the mother between 19 and 23 weeks of pregnancy, thyroid hormones, diabetes, and cancer. Additional research is needed to confirm these findings.

Unravelling the potential of angiogenic factors for the early prediction of preeclampsia

Preeclampsia is a multisystem, multiorgan hypertensive disorder of pregnancy responsible for maternal and perinatal morbidity and mortality in low- and middle-income countries. The classic diagnostic features hold less specificity for preeclampsia and its associated adverse outcomes, suggesting a need for specific and reliable biomarkers for the early prediction of preeclampsia. The imbalance of pro- and antiangiogenic circulatory factors contributes to the pathophysiology of preeclampsia. Several studies have examined the profile of angiogenic factors in preeclampsia to search for a biomarker that will improve the diagnostic ability of preeclampsia and associated adverse outcomes. This may help in more efficient patient management and the reduction of associated health care costs. This article reviews the findings from previous studies published to date on angiogenic factors and suggests a need to apply a multivariable model from the beginning of pregnancy and continuing throughout gestation for the early and specific prediction of preeclampsia.

MiR-124-3p promotes trophoblast cell HTR-8/SVneo pyroptosis by targeting placental growth factor

INTRODUCTION

MiR-124-3p is one of the aberrantly expressed miRNAs in the placentas of patients with preeclampsia (PE), a severe obstetric complication characterised by hypertension and proteinuria. This study aimed to investigate the role of miR-124-3p in the invasion, migration and death of trophoblast cells and explore the potential mechanisms.

METHODS

MiR-124-3p expression in placental tissues was compared with that in normal placenta. HTR8/SVneo cells were then transfected with miR-124-3p mimics to examine cellular apoptosis, migration and invasion. Furthermore, the expression of pyroptosis-related molecular NLRP3, Pro-caspase1, caspase1, IL-1β and GSDMD was examined with Western blot. Dual luciferase reporter assay was performed to confirm that placental growth factor (PLGF) is a direct target of miR-124-3p, and HTR-8/SVneo cells were transfected with small interfering RNA PLGF (siPLGF) to determine whether PLGF knockdown promotes HTR-8/SVneo pyroptosis. Finally, intracellular ROS was diminished with N-acetyl-l-cysteine (NAC) to observe whether the pro-pyroptosis effect of PLGF knockdown is alleviated.

RESULTS

Results in this study showed that miR-124-3p expression was remarkably increased in the placenta of patients with PE. Moreover, the transfection of miR-124-3p mimics in trophoblastic cells significantly decreased cell migration and invasion but increased cell apoptosis and the expression of NLRP3, pro-caspase1, caspase1, IL-1β and GSDMD. Therefore, PLGF was confirmed as a direct target of miR-124-3p. Finally, siPLGF transfection can mimic the effects of miR-124-3p, and NAC can inhibit this effect.

CONCLUSION

In summary, miR-124-3p is upregulated in PE, and in vitro functional analysis revealed that this mRNA inhibits trophoblast invasion and migration but promotes cell pyroptosis partly via the PLGF-ROS pathway.

High glucose condition inhibits trophoblast proliferation, migration and invasion by downregulating placental growth factor expression

AIM

This study aimed to investigate the effect of high glucose (HG) level on the proliferation, migration and invasion of trophoblasts and determine the role of placental growth factor (PLGF) in the process.

METHODS

HTR8-S/Vneo was treated with different concentrations of d-glucose (0, 10, 15, 20, 25 and 30 μM) at different times (0, 6, 12 and 24 h). qRT-PCR and Western blot analyses were used to measure PLGF expression. The protein level of PLGF was measured by immunofluorescence. Cell proliferation was assessed with CCK-8 analysis. Wound healing and transwell assays were used to evaluate cell migration and invasion. Intercellular ROS was detected with DCFH-DA.

RESULTS

After d-glucose treatment, the viability decreased in 25 and 30 μM groups. The HG group (25 μM) showed inhibited cell migration and invasion ability. The mRNA and protein levels of PLGF decreased under HG condition. Elevated ROS production was also detected in the HG group. Knocked-down PLGF expression enhanced increased ROS production and decreased cell migration and invasion, which reverted to the original levels after PLGF was overexpressed.

CONCLUSION

High glucose treatment inhibited HTR8-S/Vneo viability, migration and invasion by downregulating PLGF expression.