Alterations of Serum and Placental Endoglin in Pre-Eclampsia

From Biomarkers to the Molecular Mechanism of Preeclampsia-A Comprehensive Literature Review

Preeclampsia (PE) is a prevalent obstetric illness affecting pregnant women worldwide. This comprehensive literature review aims to examine the role of biomarkers and understand the molecular mechanisms underlying PE. The review encompasses studies on biomarkers for predicting, diagnosing, and monitoring PE, focusing on their molecular mechanisms in maternal blood or urine samples. Past research has advanced our understanding of PE pathogenesis, but the etiology remains unclear. Biomarkers such as PlGF, sFlt-1, PP-13, and PAPP-A have shown promise in risk classification and preventive measures, although challenges exist, including low detection rates and discrepancies in predicting different PE subtypes. Future perspectives highlight the importance of larger prospective studies to explore predictive biomarkers and their molecular mechanisms, improving screening efficacy and distinguishing between early-onset and late-onset PE. Biomarker assessments offer reliable and cost-effective screening methods for early detection, prognosis, and monitoring of PE. Early identification of high-risk women enables timely intervention, preventing adverse outcomes. Further research is needed to validate and optimize biomarker models for accurate prediction and diagnosis, ultimately improving maternal and fetal health outcomes.

Alterations of angiopoietin-related growth factor (Angptl6) during pregnancy and in pre-eclampsia

AIM

The aim of this study was to clarify the alterations of angiopoietin-related growth factor (AGF, also known as Angptl6/ARP5) in the serum of normally pregnant women and pre-eclamptic women and to explore the role of AGF in pre-eclampsia.

MATERIAL AND METHODS

Thirty healthy non-pregnant women, 118 normally pregnant women (30 at 6-12 gestational weeks, 30 at 13-28 weeks and 58 at 29-40 weeks, respectively) and 46 pre-eclamptic women were recruited. Fasting blood samples were obtained from all subjects. Fifteen women of healthy pregnant women provided their blood samples at 24 and 48 h after cesarean section, respectively. Enzyme-linked immunosorbent assay was used to determine the serum level of AGF.

RESULTS

Serum levels of AGF were significantly higher in normally pregnant women than non-pregnant women (P < 0.001 of all). Although serum AGF of the first trimester was significantly higher than that of the second trimester (P = 0.033), there were no significant differences of serum AGF in the comparison between the first and third trimester (P = 0.064) and between the second and third trimester (P = 0.546). Serum AGF significantly decreased after delivery (P < 0.05). There were no significant differences in AGF of maternal serum between pre-eclamptic women and normally pregnant control women (P = 0.285). There were no significant differences in circulating AGF concentration between non-pregnant women and postpartum groups (P = 0.052 for 24 h after delivery and P = 0.083 for 48 h after delivery).

CONCLUSION

The serum level of AGF was elevated in normal pregnancy compared with non-pregnant women, suggesting that placenta is an important source of circulating AGF during pregnancy.

Maternal serum endoglin as an early marker of pre-eclampsia in high-risk patients

Background

Pre-eclampsia is a potentially serious condition that still accounts for significant morbidity and mortality for the affected mother and neonate. Although the pathogenesis is not fully understood, it is now widely accepted that vascular endothelial dysfunction is the most important and principal event in the pathophysiology of the disease. The aims of our study were to compare serum soluble endoglin levels at week 13 in normotensive pregnant women and in high-risk women, to determine whether the maternal plasma soluble endoglin concentration at 26 weeks is increased in pregnancies that subsequently develop pre-eclampsia, and to identify if soluble endoglin measurement improves the results of screening for pre-eclampsia.

Methods

This work was conducted in 60 healthy pregnant controls and 110 pregnant women at high risk for pre-eclampsia. Gestational age was confirmed by date of last menstrual period and first trimester ultrasound. The time of onset of pre-eclampsia was defined as the time of first elevated blood pressure or urinary protein measurement leading to the diagnosis. Blood samples were collected for measurement of soluble endoglin and other routine laboratory tests, including measurement of urinary proteins. Serum soluble endoglin was estimated by sandwich enzyme-linked immunosorbent assay.

Results

There was a highly significant increase in serum soluble endoglin in high-risk women compared with controls at week 13 (P < 0.001). Further determination of soluble endoglin revealed a more significant increase in women who developed early-onset pre-eclampsia compared with those who developed late-onset pre-eclampsia. Moreover, a significant positive correlation was found between soluble endoglin and both diastolic blood pressure and total urinary protein, ie, severity of pre-eclampsia.

Conclusion

Estimation of serum soluble endoglin at gestational week 13 could be used as a sensitive screening test for women at high risk of developing pre-eclampsia prior to onset of its clinical manifestations, which could potentially improve the outcome of pregnancy.

Screening for pre-eclampsia using serum placental growth factor and endoglin with Down's syndrome Quadruple test markers

OBJECTIVE

To estimate the pre-eclampsia screening performance of placental growth factor (PlGF) and endoglin with second-trimester Quadruple test markers used for antenatal Down's syndrome screening.

METHODS

A nested case-control study of 88 pregnant women with known early second-trimester Down's syndrome Quadruple test marker levels who subsequently developed pre-eclampsia and 275 unaffected controls. Frozen maternal serum samples were thawed and assayed for PlGF and endoglin. Monte Carlo simulation was used to estimate the pre-eclampsia screening performance of a pre-eclampsia detection algorithm using the Quadruple test markers with or without the addition of PlGF and/or endoglin.

RESULTS

Median PlGF was 33% lower (95% confidence interval 24-41%) and endoglin 31% (20-43%) higher in pre-eclampsia than in unaffected pregnancies. Adding PlGF to the Quadruple test markers increased the pre-eclampsia detection rate from 34% to 45% at a 5% false-positive rate - it increased it to 43% with endoglin and to 50% with both. The corresponding estimates for early pre-eclampsia (before 36 weeks' gestation) were a few percentage points higher (48%, 48% and 55% respectively). Including information on parity, pre-eclampsia in a previous pregnancy, family history (woman's mother) and assuming a pre-eclampsia prevalence of 2%, the detection rates for a 5% false-positive rate were 39% with the Quadruple test markers, 48% with addition of endoglin, 49% with addition of PlGF, and 54% with addition of both.

CONCLUSIONS

Adding PlGF to the Quadruple test Down's syndrome screening markers improves pre-eclampsia screening performance. There is a modest extra benefit in also adding the measurement of endoglin.