Blood laboratory testing for early prediction of preeclampsia: chasing the finish line or at the starting blocks?

Identification of novel first-trimester serum biomarkers for early prediction of preeclampsia

BACKGROUND

Preeclampsia (PE) is a leading cause of maternal and perinatal mortality and morbidity worldwide, but effective early prediction remains a challenge due to the lack of reliable biomarkers.

METHODS

Based on the extensive human biobank of our large-scale assisted reproductive cohort platform, the first-trimester serum levels of 48 cytokines, total immunoglobulins (Igs), anti-phosphatidylserine (aPS) antibodies, and several previously reported PE biomarkers [including placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and activin A] were measured in 34 women diagnosed with PE and 34 matched normotensive controls.

RESULTS

The PE group has significantly higher first-trimester serum levels of interleukin (IL)-2Rα, IL-9, tumor necrosis factor-β (TNF-β), RANTES, hepatocyte growth factor (HGF), total IgM, and total IgG, and aPS IgG optical density (OD) value, as well as lower first-trimester serum levels of PlGF and total IgA and aPS-IgG immune complexes (IC) OD value than the control group. Combining top five first-trimester serum biomarkers (total IgM, total IgG, PlGF, aPS IgG, and total IgA) achieved superior predictive value [area under the curve (AUC) and 95% confidence interval (CI) 0.983 (0.952-1.000), with a sensitivity of 100% and a specificity of 94.1%] for PE development compared to PlGF and PlGF/sFlt-1 independently [AUC and 95% CI 0.825 (0.726-0.924) and 0.670 (0.539-0.800), respectively].

CONCLUSION

We identified novel first-trimester serum biomarkers and developed an effective first-trimester prediction model using immune-related factors and PlGF for PE, which could facilitate the development of early diagnostic strategies and provide immunological insight into the further mechanistic exploration of PE.

Investigation of the relationship between changes in maternal coagulation profile in the first trimester and the risk of developing preeclampsia

Normal pregnancy is a hypercoagulable state with an increase in coagulation factor levels and a decrease in natural anticoagulation. However, a higher hypercoagulable state with prolonged activated partial thromboplastin time (APTT), prothrombin time (PT), increased D-dimer, and mean platelet volume is seen in women with preeclampsia at the time of onset. In addition, endothelial dysfunction occurs before the clinical symptoms of preeclampsia. Therefore, we undertook this study to investigate the coagulation profile in the first trimester in women who developed preeclampsia later. A total of 853 pregnant women with singleton births at the Obstetrics and Gynecology Hospital of Fudan University between January 2021 and December 2021 were included in this case-control study. In the comparison with the controls (n = 531), the mean value of D-dimer, APTT, thrombin time (TT), antithrombin (AT)), and fibrin degradation products (FDP) was significantly lower in preeclamptic women at the time of diagnosis (n = 322). The changes in the coagulation profile were not associated with the severity or the time of onset. The reduced values of D-dimer, AT, and FDP, and increased values of TT were also observed in the first trimester in women who developed preeclampsia later and were not associated with the severity, or the time of onset of preeclampsia. After adjusting for maternal age and BMI, the values of D-dimer and AT in the first trimester were correlated to the risk of developing preeclampsia. Our findings suggest that there is an abnormal maternal response to the hemostatic system in early gestational age in women who developed preeclampsia later and measuring the coagulation profile could be an additional predictive marker of preeclampsia.

Role of epigenetics in parturition and preterm birth

Preterm birth occurs worldwide and is associated with high morbidity, mortality, and economic cost. Although several risk factors associated with parturition and preterm birth have been identified, mechanisms underlying this syndrome remain unclear, thereby limiting the implementation of interventions for prevention and management. Known triggers of preterm birth include conditions related to inflammatory and immunological pathways, as well as genetics and maternal history. Importantly, epigenetics, which is the study of heritable phenotypic changes that occur without alterations in the DNA sequence, may play a role in linking social and environmental risk factors for preterm birth. Epigenetic approaches to the study of preterm birth, including analyses of the effects of microRNAs, long non-coding RNAs, DNA methylation, and histone modification, have contributed to an improved understanding of the molecular bases of both term and preterm birth. Additionally, epigenetic modifications have been linked to factors already associated with preterm birth, including obesity and smoking. The prevention and management of preterm birth remains a challenge worldwide. Although epigenetic analysis provides valuable insights into the causes and risk factors associated with this syndrome, further studies are necessary to determine whether epigenetic approaches can be used routinely for the diagnosis, prevention, and management of preterm birth.

Preeclampsia Among African American Pregnant Women: An Update on Prevalence, Complications, Etiology, and Biomarkers

Importance

Preeclampsia is a devastating disease of pregnancy associated with increased risk of fetal and maternal complications. African American pregnant women have a high prevalence of preeclampsia, but there is a need of systemic analyses of this high-risk group regarding complications, etiology, and biomarkers.

Objective

The aim of this study was to provide a synopsis of current research of preeclampsia specifically related to African American women.

Evidence Acquisition

A comprehensive search was performed in the bibliographic database PubMed with keywords "preeclampsia" and "African American."

Results

African American women with preeclampsia were at an increased risk of preterm birth, which resulted in low-birth-weight infants. Intrauterine fetal death among African American preeclamptic patients occurs at twice the rate as in other races. On the maternal side, African American mothers with preeclampsia have more severe hypertension, antepartum hemorrhage, and increased mortality. Those who survive preeclampsia have a high risk of postpartum cardiometabolic disease. Preexisting conditions (eg, systemic lupus erythematosus) and genetic mutations (eg, sickle cell disease in the mother, FVL or APOL1 mutations in the fetus) may contribute to the higher prevalence and worse outcomes in African American women. Many blood factors, for example, the ratio of proteins sFlt/PlGF, hormones, and inflammatory factors, have been studied as potential biomarkers for preeclampsia, but their specificity needs further investigation.

Conclusions

Further studies of preeclampsia among African American women addressing underlying risk factors and etiologies, coupled with identification of preeclampsia-specific biomarkers allowing early detection and intervention, will significantly improve the clinical management of this devastating disease.

Evaluation of circ_100219 and miR-135b in serum and exosomes of healthy pregnant women

Aim: Circular RNAs (circRNAs) are recently discovered and highly stable noncoding RNAs acting as gene regulators. These circRNAs can function as miRNA sponges, thereby upregulating or downregulating miRNA target gene expression. MiR-135b is expressed in placenta tissue and can be found in maternal circulation, thus playing a functional role in pregnancy. This miR is a target of circ_100219. This preliminary study was aimed to evaluate circ_100219 and miR-135b expression in pregnant and nonpregnant women, and explore the relationship between circ_100219 and miR-135b in serum and exosomes.Methods: Total RNA was isolated from serum and exosomes of 30 healthy pregnant women (32.9 ± 5.1 years) between 23-27 gestational weeks and 30 healthy nonpregnant women (31.3 ± 5.4 years). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to quantify circ_100219 and miR-135b expression. GAPDH and U6 snRNA were chosen as reference for normalizing expression levels. The differences between pregnant and nonpregnant women were assessed with Mann-Whitney test and correlation with Spearman's test.Results: The circ_100219 expression levels were significantly lower both in serum and exosomes of second trimester pregnant women compared to the control group (p < .0001), whilst Mir-135b expression levels were significantly higher in pregnant than in the control group (p < .0001). A significant negative correlation was observed between circ_100219 and miR-135b expression levels in both serum and exosomes (r = -0.34 and p = .009; r = -0.31 and p = .01, respectively). The circ_100219:miR-135b ratio was significantly increased in nonpregnant women compared to the pregnant group, in both serum and exosomes (49.0 versus 1.1, p < .0001 and 2042.4 versus 28.5, p < .0001, respectively).Conclusions: Our results confirm a role for circ_100219 and miR-135b in physiological pregnancy. Further studies are needed to investigate the circ_100219:miR-135b ratio in pregnancy complications.

Stability of placental growth factor, soluble fms-like tyrosine kinase 1, and soluble fms-like tyrosine kinase 1 e15a in human serum and plasma

Placental growth factor (PlGF), total soluble fms-like tyrosine-kinase 1 (sFlt-1) and its placental-specific variant, sFlt-1 e15a, show promise as biomarkers for the prediction and diagnosis of preeclampsia. This study describes the degradation of PlGF, sFlt-1 and sFlt-1 e15a within maternal serum and plasma to assist clinical implementation. Whole blood was refrigerated at 4 °C for up to 48 h prior to centrifugation for isolation of plasma and serum. PlGF and sFlt-1 were quantified using the B.R.A.H.M.S Kryptor Compact PLUS; sFlt-1 e15a via a custom ELISA. All three analytes are stable for at least 48 h at 4 °C. Serum and plasma performed comparably.

The Role of miRNAs as Biomarkers for Pregnancy Outcomes: A Comprehensive Review

Several studies showed that altered expression of the miRNA-ome in maternal circulation or in placental tissue may reflect not only gestational disorders, such as preeclampsia, spontaneous abortion, preterm birth, low birth weight, or macrosomia, but also prenatal exposure to environmental pollutants. Generally, the relationships between environmental exposure, changes in miRNA expression, and gestational disorders are explored separately, producing conflicting findings. However, validation of tissue-accessible biomarkers for the monitoring of adverse pregnancy outcomes needs a systematic methodological approach that takes also into account early-life environmental exposure. To achieve this goal, exposure to xenochemicals, endogenous agents, and diet should be assessed. This study has the aim to provide a comprehensive review on the role of miRNAs as potential biomarkers for adverse pregnancy outcomes and prenatal environmental exposure.