The role of genetics in pre-eclampsia and potential pharmacogenomic interventions

Genetic Insights and Neonatal Outcomes in Preeclampsia and Eclampsia: A Detailed Analysis of the RS5707 Genotype

BACKGROUND

Preeclampsia (PE) and eclampsia (E) are severe pregnancy complications with significant maternal and neonatal health impacts. This study explores the association of the rs5707 polymorphism in the renin-angiotensin system (RAS) with PE/E and related neonatal outcomes.

MATERIALS AND METHODS

We conducted a cross-sectional study involving 400 mother-newborn dyads at the "Pius Brinzeu" Emergency Clinical Hospital Timisoara. Participants were divided into a control group (254 normotensive women) and a PE/E group (146 women with PE/E). Genotyping for the rs5707 polymorphism was performed using real-time PCR, and statistical analyses assessed associations with maternal body mass index (BMI) and neonatal outcomes.

RESULTS

The AA genotype of rs5707 was significantly associated with a reduced risk of PE/E and more favorable neonatal outcomes, including higher Apgar scores, greater birth weights, and longer gestational ages. Conversely, the AC genotype correlated with increased maternal BMI and adverse neonatal outcomes. Odds ratios highlighted the protective effect of the AA genotype against PE/E and the increased risk associated with the AC genotype.

CONCLUSIONS

This study revealed the critical role of the rs5707 polymorphism in PE/E development and neonatal health. Genetic screening for rs5707 could enhance early identification and personalized intervention strategies, improving outcomes for both mothers and neonates. Further research is needed to validate these findings across diverse populations and to uncover the underlying mechanisms.

The relationship between Toll-like receptor-4 genes and preeclampsia outcomes

PURPOSE

The study aimed to analyse the relationship of the rs4986790 locus of the TLR4 gene with the overall risk of preeclampsia, including both its early and late forms.

METHODS

The study used standard genetic analysis methods such as DNA extraction, PCR amplification, and genotyping of the rs4986790 locus of the TLR4 gene to assess the association with the development of preeclampsia and peripartal stroke in 207 pregnant women from the southern regions of Kazakhstan from 2016 to 2022, of whom 103 had peripartal stroke on the background of preeclampsia (the main group) and 104 preeclampsia (comparative group).

RESULTS

The results of the study demonstrate that the AG and AG + GG genotypes at the rs4986790 locus of the TLR4 gene are significantly associated with an increased risk of developing an early form of preeclampsia. This opens up a new perspective in the identification of genetic markers that can serve as indicators of a tendency to develop preeclampsia in earlier periods of pregnancy.

CONCLUSION

It was noted that the rs4986790 locus did not show a statistically significant association with the risk of late preeclampsia. An important aspect of the study revealed the relationship of genotypes with the development of peripartal stroke on the background of preeclampsia. This study offers practical insights for creating targeted genetic screening and personalised treatments for preeclampsia, aiming to improve patient outcomes. To fully understand the molecular mechanisms underlying the identified association, additional research is required to identify deeper molecular pathways and relationships, and to develop new strategies for the prevention and treatment of preeclampsia.

Association of IL-6 -176G > C Polymorphism with Susceptibility to Preeclampsia: A Systematic Review and Meta-Analysis

Background: Many studies have described the influence of -176G > C polymorphism of the IL-6 gene on susceptibility to preeclampsia. However, the results have remained inconclusive and controversial. Therefore, we performed a meta-analysis to more precisely determine the association between the IL-6 -176G > C polymorphism and preeclampsia risk. Methods: Electronic databases including PubMed, Embase, Web of Science, and CNKI were searched up to August 15, 2019. The pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were used to calculate the association. Results: A total of 12 studies with 1,821 preeclampsia cases and 3,339 controls were selected. Overall, no significant association was found between IL-6 -176G > C polymorphism and preeclampsia risk. In the stratified analyses by ethnicity, there was a significant association in Asians, but not in Caucasians and mixed populations. Conclusions: The results of meta-analysis indicated that IL-6 -176G > C polymorphism was not significantly associated with risk of preeclampsia in overall population.

An Insight into the Angiogenic and Lymphatic Interplay in Pre-eclampsia Comorbid with HIV Infection

PURPOSE OF REVIEW

To provide insight on the imbalance of angiogenic and lymphangiogenic factors in pre-eclampsia, as well as highlight polymorphism in genes related to angiogenesis and lymphangiogenesis.

RECENT FINDINGS

The pregnancy-specific disorder pre-eclampsia is diagnosed by the presence of hypertension with/without proteinuria, after 20 weeks of gestation. The pathogenesis of pre-eclampsia remains ambiguous, but research over the years has identified an imbalance in maternal and foetal factors. Familial predisposition and gene variation are also linked to pre-eclampsia development. The sFlt-1/PIGF ratio has attracted great attention over the years; more recently several researchers have reported that a sFlt-1/PIGF ratio of ≤ 38 can be used to predict short-term absence of pre-eclampsia. This ratio has the potential to prevent adverse pregnancy outcomes and reduce healthcare costs significantly. Genome-wide studies have additionally identified variation in the foetal gene near Flt-1. The development of preeclampsia is not limited to the maternal interface, but foetal involvement as well as genetic interplay is associated with the disorder.

The influence of gestational diabetes mellitus (GDM) and gestational hypertension (GH) on placental morphological changes

Gestational diabetes mellitus (GDM) and gestational hypertension (GH) are some of the most common medical conditions associated with pregnancy. These can be correlated with placental morphopathological changes and implicitly can influence good fetal development. The age and weight of the mother can be correlated directly proportionally with those of the fetus but also with histoarchitecture and placental vascularization. The placental appearance associated with GDM and GH reveals macroscopic features, such as calcifications, fibrin deposits and placental infarcts, but the most relevant pathological features are the microscopic ones, highlighted by the classical staining techniques: Hematoxylin-Eosin (HE), Periodic Acid-Schiff (PAS)-Hematoxylin and Masson's trichrome (MT), but also by immunohistochemical technique with the help of the anti-cluster of differentiation 34 (CD34) antibody that labeled the capital endothelium in the structure of the placental terminal villi and thus we were able to quantify the vascular density according to the associated medical pathology. The microscopic changes identified were represented by intravillous and extravillous fibrin depositions, massive placental infarctions caused by vascular suppression due to various causes, such as thrombosis, but also placental calcifications. All these macroscopic and microscopic morphopathological changes, together with the clinical data of the mother and the newborn, we have demonstrated that they are interconnected and that they can vary depending on the pathology, GH or GDM.

Pharmacogenomics of Hypertension and Preeclampsia: Focus on Gene-Gene Interactions

Hypertension is a leading cause of cardiovascular mortality, but only about half of patients on antihypertensive therapy achieve blood pressure control. Preeclampsia is defined as pregnancy-induced hypertension and proteinuria, and is associated with increased maternal and perinatal mortality and morbidity. Similarly, a large number of patients with preeclampsia are non-responsive to antihypertensive therapy. Pharmacogenomics may help to guide the personalized treatment for non-responsive hypertensive patients. There is evidence for the association of genetic variants with variable response to the most commonly used antihypertensive drugs. However, further replication is needed to confirm these associations in different populations. The failure to replicate findings from single-locus association studies has prompted the search for novel statistical methods for data analysis, which are required to detect the complex effects from multiple genes to drug response phenotypes. Notably, gene–gene interaction analyses have been applied to pharmacogenetic studies, including antihypertensive drug response. In this perspective article, we present advances of considering the interactions among genetic polymorphisms of different candidate genes within pathways relevant to antihypertensive drug response, and we highlight recent findings related to gene–gene interactions on pharmacogenetics of hypertension and preeclampsia. Finally, we discuss the future directions that are needed to unravel additional genes and variants involved in the responsiveness to antihypertensive drugs.

Genetic Approaches in Preeclampsia

Preeclampsia (PE) is a serious hypertensive disorder that affects up to 8% of all pregnancies annually. An established risk factor for PE is family history, clearly demonstrating an underlying genetic component to the disorder. To date, numerous genetic studies, using both the candidate gene and genome-wide approach, have been undertaken to tease out the genetic basis of PE and understand its origins. Such studies have identified some promising candidate genes such as STOX1 and ACVR2A. Nevertheless, researchers face ongoing challenges of replicating these genetic associations in different populations and performing the functional validation of identified genetic variants to determine their causality in the disorder. This chapter will review the genetic approaches used in the study of PE, discuss their limitations and possible confounders, and describe current strategies.

Personalized Therapy Against Preeclampsia by Replenishing Placental Protein 13 (PP13) Targeted to Patients With Impaired PP13 Molecule or Function

Hypertensive disorders affect about one third of all people aged 20 and above, and are treated with anti-hypertensive drugs. Preeclampsia (PE) is one form of such disorders that only develops during pregnancy. It affects ten million pregnant women globally and additionally causes fetal loss and major newborn disabilities. The syndrome's origin is multifactorial, and anti-hypertensive drugs are ineffective in treating it. Biomarkers are helpful for predict its development. Generic drugs, such as low dose aspirin, were proven effective in preventing preterm PE. However, it does not cure the majority of cases and many studies are underway for fighting PE with extended use of additional generic drugs, or through new drug development programs. This review focuses on placental protein 13 (PP13). This protein is only expressed in the placenta. Impaired PP13 DNA structure and/or its reduced mRNA expression leads to lower blood PP13 level that predict a higher risk of developing PE. Two polymorphic PP13 variants have been identified: (1) The promoter PP13 variant with an "A/A" genotype in the -98 position (versus "A/C" or "C/C"). Having the "A/A" genotype is coupled to lower PP13 expression, mainly during placental syncytiotrophoblast differentiation and, if associated with obesity and history of previous preeclampsia, it accurately predicts higher risk for developing the disorder. (2) A thymidine deletion at position 221 causes a frame shift in the open reading frame, and the formation of an early stop codon resulting in the formation of DelT221, a truncated variant of PP13. In pregnant rodents, both short- and long- term replenishment of PP13 causes reversible hypotension and vasodilation of uterine vessels. Long-term exposure is also accompanied by the development of larger placentas and newborns. Also, only w/t PP13 is capable of inducing leukocyte apoptosis, providing maternal immune tolerance to pregnancy. Based on published data, we propose a targeted PP13 therapy to fight PE, and consider the design and conduct of animal studies to explore this hypothesis. Accordingly, a new targeted therapy can be implemented in humans combining prediction and prevention.

The placental vascular endothelial growth factor polymorphisms and preeclampsia/preeclampsia severity

Preeclampsia (PE) is a serious pregnancy-specific condition, which originates from placenta and finishes after delivery. The present study has investigated the association between placental VEGF I/D (rs35569394), -1154G/A (rs1570360), and -634G/C(rs2010963) polymorphisms and maternal VEGF -2549 I/D (rs35569394) polymorphism with PE and PE severity. In this case-control study, the maternal blood of 217 women with PE and 210 normotensive pregnant women and the placenta of 84 PE women and 103 normotensive women were collected after delivery. Genotyping was done by PCR or PCR-RFLP methods. The maternal VEGF-2549I/D genotypes were not associated with PE or PE severity. The placental VEGF -2549 I/D genotypes were not associated with PE too; however; the placental VEGF-2549 DD genotype was statistically different between women with severe PE and mild PE or the controls. The placental VEGF -634GC and CC genotypes were significantly higher in PE women and associated with 2.6 and 2-fold higher risk of PE, respectively. The VEGF -634GC and CC genotypes were associated with PE severity. No association was found between placental VEGF -1154G/A polymorphism and PE or PE severity. The placental DGC haplotype of VEGF -2549 I/D, -1154G/A, and -634G/C polymorphisms was associated with 2.9-fold higher risk of PE. However, the placental IAG haplotype was associated with 0.3-fold lower risk of PE. In conclusion, the placental VEGF -2549 DD genotype was associated with severe PE and the placental -634GC and CC genotypes were associated with PE and severe PE. No association was found between VEGF -1154G/A polymorphism and PE or PE severity.

Protective Role of Maternal P.VAL158MET Catechol-O-Methyltransferase Polymorphism against Early-Onset Preeclampsia and its Complications

Background

Up until now there have been contradictory data about the association between p.Val158Met catechol-O-methyltransferase (COMT) polymorphism and risk of preeclampsia (PE). The goal of this study was to assess the potential correlation between p.Val158Met COMT polymorphism and risk of early-onset PE, risk of a severe form of early-onset PE, as well as risk of small-for-gestational-age (SGA) complicating PE.

Methods

The study included 47 early-onset PE patients and 47 control cases. Forty-seven early-onset PE patients were grouped by disease severity (33 patients with a severe form and 14 patients without severe features) and secondly by size for gestational age (12 patients with appropriate-for-gestational-age (AGA) and 35 patients with SGA size). p.Val158Met polymorphism was genotyped by PCR-RFLP analysis.

Results

Allele analysis showed significant difference in COMT allele distribution between early-onset PE and control group as well as early-onset PE SGA and controls (p=0.04057 and p=0.0411 respectively). A statistically significant distribution difference between the severe form and form without severe features of early-onset PE patients was not observed (p>0.05). The highest difference observed was in the allele recessive model where COMT MetMet genotype was associated with decreased risk of early-onset PE (OR=0.281; 95%CI = 0.092–0.7836) and PE complications including severe early-onset PE (OR= 0.304; 95%CI=0.086–0.944) and SGA early-onset PE (OR=0.284; 95%CI=0.081–0.874).

Conclusions

COMT may be used as a candidate gene for early-onset PE and its severe form and SGA complications.

In-vitro study of the effect of anti-hypertensive drugs on placental hormones and angiogenic proteins synthesis in pre-eclampsia

INTRODUCTION

Antihypertensive drugs lower the maternal blood pressure in pre-eclampsia (PE) by direct or central vasodilatory mechanisms but little is known about the direct effects of these drugs on placental functions.

OBJECTIVE

The aim of our study is to evaluate the effect of labetolol, hydralazine, α-methyldopa and pravastatin on the synthesis of placental hormonal and angiogenic proteins know to be altered in PE.

DESIGN

Placental villous explants from late onset PE (n = 3) and normotensive controls (n = 6) were cultured for 3 days at 10 and 20% oxygen (O2) with variable doses anti-hypertensive drugs. The levels of activin A, inhibin A, human Chorionic Gonadotrophin (hCG), soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng) were measured in explant culture media on day 1, 2 and 3 using standard immunoassays. Data at day 1 and day 3 were compared.

RESULTS

Spontaneous secretion of sEndoglin and sFlt-1 were higher (p < 0.05) in villous explants from PE pregnancies compared to controls. There was a significant time dependent decrease in the secretion of sFlt-1 and sEndoglin in PE cases, which was seen only for sFlt-1 in controls. In both PE cases and controls the placental protein secretions were not affected by varying doses of anti-hypertensive drugs or the different O2 concentration cultures, except for Activin, A which was significantly (p < 0.05) higher in controls at 10% O2.

INTERPRETATION

Our findings suggest that the changes previously observed in maternal serum hormones and angiogenic proteins level after anti-hypertensive treatment in PE could be due to a systemic effect of the drugs on maternal blood pressure and circulation rather than a direct effect of these drugs on placental biosynthesis and/or secretion.

Pharmacogenetics and individualizing drug treatment during pregnancy

Pharmacogenetics as a tool to aid clinicians implement individualized pharmacotherapy is utilized in some areas of medicine. Pharmacogenetics in pregnancy is still a developing field. However, there are several areas of obstetric therapeutics where data are emerging that give glimpses into future therapeutic possibilities. These include opioid pain management, antihypertensive therapy, antidepressant medications, preterm labor tocolytics, antenatal corticosteroids and drugs for nausea and vomiting of pregnancy, to name a few. More data are needed to populate the therapeutic models and to truly determine if pharmacogenetics will aid in individualizing pharmacotherapy in pregnancy. The objective of this review is to summarize current data and highlight research needs.

Association of angiotensinogen gene polymorphisms and angiogenic factors with preeclampsia in Chinese women

OBJECTIVE

To investigate the association of angiotensinogen (AGT) gene polymorphisms and angiogenic factors with preeclampsia (PE) in Chinese women.

METHODS

A study on Chinese women was performed. Detection of the M235T polymorphism of AGT gene was carried out by PCR. Using a χ² test, genotype and allele frequencies were compared in all groups. Maternal serum levels of vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) and soluble fms-like tyrosine kinase 1 (sFlt1) at gestation were compared between 92 women with PE and 100 controls by ELISA.

RESULTS

Compared to the controls, the AGT homozygous of TT genotype in PE occurred significantly more frequently and the T allele was observed to occur more frequently than the M allele (p < 0.05). sFlt1 was present in high quantities in the serum of women with PE and was associated with low levels of free VEGF and PlGF (p < 0.05). Plasma sFlt1 levels are higher in PE patients with TT heterozygotes compared with MM homozygotes, but PIGF is lower (p < 0.05). Plasma VEGF concentrations showed no significant difference.

CONCLUSIONS

Our study showed that AGT M235T polymorphism is associated with PE in Chinese women. Furthermore, the gene polymorphism of the components of the renin-angiotensin system may contribute to the concentration alterations of sFlt1, VEGF, and PlGF in maternal serum, which causes disordered vasculogenesis contributing to PE.

The maternal HLA-G 1597ΔC null mutation is associated with increased risk of pre-eclampsia and reduced HLA-G expression during pregnancy in African-American women

The non-classical major histocompatibility complex molecule, human leukocyte antigen (HLA)-G, is thought to contribute to maternal immune tolerance and successful placentation during pregnancy. Genetic polymorphisms in HLA-G are known to influence expression levels as well as the relative expression of individual protein isoforms. As diminished or aberrant HLA-G expression patterns may contribute to the development of certain pregnancy complications, we sought to investigate the association between functional HLA-G polymorphisms and the risk of pre-eclampsia (PE) in African-American women. The association between maternal and fetal genotype at six HLA-G polymorphisms and risk of PE was assessed in 372 pregnancies (314 normotensive; 58 pre-eclamptic). We observed an elevated risk of PE (P = 0.00027) in pregnancies where the mother carried the 1597ΔC allele, a null allele that abolishes expression of full-length HLA-G isoforms. Furthermore, the frequency of the maternal 1597ΔC allele was highest in the subset of pre-eclamptic pregnancies that were delivered preterm, suggesting an association between the null allele and the severity of PE. We then replicated the association between higher maternal 1597ΔC allele frequency and increased severity of PE (P = 0.038) in an independent sample of 533 African-American women. Finally, to investigate the mechanistic basis of this association, we measured circulating soluble HLA-G (sHLA-G) concentrations in maternal serum collected during pregnancy in 51 healthy, normotensive African-American control women and found significantly lower levels in women carrying the 1597ΔC allele (P = 0.012). These results demonstrate that maternal HLA-G genotype is significantly associated with risk of PE in African-American women and is predictive of circulating sHLA-G levels during pregnancy.