Pre-Existing Diabetes Mellitus, Hypertension and KidneyDisease as Risk Factors of Pre-Eclampsia: A Disease of Theories and Its Association with Genetic Polymorphism

Pre-existing diabetes, hypertension and kidney disorders are prominent risk factors of pre-eclampsia (PE). It is a multifactorial pregnancy disorder associated with high blood pressure, proteinuria, and multiorgan failure, which develops after the 20th week of pregnancy. It is one of the most feared pregnancy disorders, as it consumes thousands of fetomaternal lives per annum. According to clinical and pathological studies, the placenta appears to be a key player in the pathogenesis of PE; however, the exact origin of this disorder is still under debate. Defective placentation and angiogenesis are the hallmarks of PE progression. This angiogenic imbalance, together with maternal susceptibility, might determine the severity and clinical presentation of PE. This article comprehensively examines the mechanisms of pathogenesis of PE and current evidence of the factors involved in its progression. Finally, this article will explore the genetic association of PE, various candidate genes, their proposed mechanisms and variants involved in its pathogenesis.

Cytokine-polymorphisms associated with Preeclampsia: A review

BACKGROUND

Preeclampsia (PE) is a syndromic disorder that affects 2% to 8% of pregnancies and is diagnosed principally when hypertension appears in the second-d half of pregnancy. WHO estimates the incidence of PE to be seven times higher in developing countries than in developed countries. Severe preeclampsia/eclampsia is one of the most important causes of maternal mortality, associated with 50,000 to 100,000 annual deaths globally as well as serious fetal and neonatal morbidity and mortality, especially in developing countries. Even though evidence from family-based studies suggest PE has a heritable component, its etiology, and specific genetic contributions remain unclear. Many studies examining the genetic factors contributing to PE have been conducted, most of them are focused on single nucleotide polymorphisms (SNPs). Given that PE has a very important inflammatory component, is mandatory to examine cytokine-SNPs for elucidating all mechanisms involved in this pathology. In this review, we describe the most important cytokine-polymorphisms associated with the onset and development of PE. We aim to provide current and relevant evidence in this regard.

METHODS

We searched English databases such as PubMed and the National Center for Biotechnology Information. The publication time of the papers was set from the establishment of the databases to February 2022. All studies about Th1/Th2/Th17 cytokines polymorphisms were included in our study.

RESULTS

SNPs in IFN-γ, TNF-α, IL-4, IL-6, IL-10, IL-17A, and IL-22 are associated with the development, early-onset and severity of PE, being the Th1/Th2/Th17 responses affected by the presence of these SNPs.

CONCLUSIONS

The changes in Th1/Th2/Th17 response modify processes such as placentation, control of inflammation, and vascular function. Nonetheless, association studies have shown different results depending on sample size, diagnostic, and population.

Association of IL-10 -819C/T, -592A/C polymorphisms with the risk of preeclampsia: An updated meta-analysis

OBJECTIVE

The purpose of our study was to investigate whether IL-10 -819C/T, -592A/C polymorphisms were associated with preeclampsia (PE) susceptibility.

METHODS

A comprehensive and systematic literature search was performed through online databases, including Web of Science, PubMed, EMBASE, and Chinese databases. Then eligible literatures were included according to inclusion criteria and exclusion criteria. Statistical data analysis was performed using Stata 10.0 software. Odds ratios (OR) and 95% confidence interval were applied to evaluated the association between IL-10 -819C/T, -592A/C polymorphisms and PE susceptibility.

RESULTS

According to inclusion and exclusion criteria, 9 case-control studies, including 1423 cases and 2031 controls, were included in this meta-analysis. Our meta-analysis revealed that no association was found between IL-10 -819C/T, -592A/C polymorphisms and the risk of PE in our study.

CONCLUSION

Our meta-analysis suggested that IL-10 -819C/T and -592A/C polymorphisms had no association with PE susceptibility, but had a significant association with PE susceptibility in Asian and Caucasian.

A review of key cytokines based on gene polymorphism in the pathogenesis of pre-eclampsia

Although a number of theories have been suggested, including roles for oxidative stress, an abnormal maternal-fetal interface, and genetic and environmental factors, the etiopathology of pre-eclampsia (PE) remains unclear. Maternal immune tolerance is important for maintaining pregnancy, and researchers have increasingly focused on the critical roles of cytokines in the pathogenesis of PE in recent years. The assessment of candidate genetic polymorphisms in PE could partially elucidate the mechanisms of susceptibility to disease, and contribute to seeking for new diagnosis and treatment methods of PE. PE can lead to severe complications, and even the death of both mother and fetus. Although the complex pathology is not yet clear, some evidence suggested that the occurrence of PE is related to inflammatory factors. We reviewed the current understandings of roles of cytokines in PE, and provided an extensive overview of the role of single nucleotide chain polymorphisms (SNPs) in the genes potentially underlying the pathophysiology of PE.

Are genetic variations in IL-1β and IL-6 cytokines associated with the risk of pre-eclampsia? Evidence from a systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis study was performed to assess the potential association between interleukin-1 beta (IL-1β) single nucleotide polymorphisms (SNPs) (rs1143634 and rs16944) and interleukin-6 (IL-6) SNP (rs1800795) and pre-eclampsia (PE).

METHODS

A comprehensive literature search was conducted in the international search engines and databases, including MEDLINE (via PubMed), Scopus, and Web of Science (ISI) up to 9 March 2021. After retrieving relevant articles, data extraction was performed by four authors independently. Pooled ORs and corresponding 95% CIs were used to evaluate the association between IL-1β and IL-6 polymorphisms and PE risk. Cochran's Q test was used to check heterogeneity, and the I² index was calculated for measuring the heterogeneity between the estimations of included studies.

RESULTS

After reviewing fully published studies, 21 studies were included in this study based on the eligibility criteria. Our results showed that rs16944 and rs1143634 of IL-1β were significantly associated with the risk of PE. Regarding rs16944, the minor C allele significantly decreased the risk of PE (C vs. T: OR = 0.79, 95% CI = 0.69-0.90). In contrast, the minor T allele of rs1143634 significantly increased the risk of PE (T vs. C: OR = 1. 28, 95% CI = 1.04-1.58). There was no significant association between IL-6 rs1800795 (C vs. G: OR = 1.04, 95% CI = 0.93-1.16) polymorphism and PE risk.

CONCLUSIONS

In conclusion, this meta-analysis suggests rs1143634 and rs16944 polymorphisms of IL-1β are related to the risk of PE.

Association of Interleukin-10 -1082G > A Polymorphism with Susceptibility to Preeclampsia: A Systematic Review and Meta-Analysis Based on 21 Studies

Background: Previous studies have reported the association between IL-10 -1082 G > A polymorphism and preeclampsia risk, but the results remained controversial. Therefore, this meta-analysis was performed to evaluate the association of IL-10 -1082 G > A polymorphism with preeclampsia risk.Methods: We searched PubMed, ISI Web of Knowledge and CNKI databases to identify eligible studies up to September 05, 2019.Results: A total of 21 case-control studies with 3,510 cases and 5,874 controls were selected. The results revealed that IL-10 -1082 G > A polymorphism was significantly associated with an increased risk of preeclampsia under the recessive model (AA vs. AG + GG: OR = 1.191, 95% CI = 1.018-1.394, P = 0.029). Stratified analyses by ethnicity revealed a significantly increased risk of preeclampsia in Asian and mixed populations, but not in Caucasians. Moreover, there was a significant association among Chinese and Brazilian.Conclusions: Our results showed that IL-10 -1082 G > A polymorphism was significantly associated with an increased risk of preeclampsia.

Comparative risks and predictors of preeclamptic pregnancy in the Eastern, Western and developing world

Preeclampsia (PE) is a complication of pregnancy characterized by hypertension (HTN-Preg), and often proteinuria. If not managed promptly, PE could lead to eclampsia and seizures. PE could also lead to intrauterine growth restriction (IUGR) and prematurity at birth. Although PE is a major cause of maternal and fetal morbidity and mortality, the underlying mechanisms are unclear. Also, there is a wide variability in the incidence of PE, ranging between 2 and 8% of pregnancies in the Eastern, Western and Developing world, suggesting regional differences in the risk factors and predictors of the pregnancy-related disorder. Several demographic, genetic, dietary and environmental factors, as well as maternal circulating biomarkers have been associated with PE. Demographic factors such as maternal race and ethnicity could play a role in PE. Specific genetic polymorphisms have been identified in PE. Maternal age, parity, education and socioeconomic status could be involved in PE. Dietary fat, protein, calcium and vitamins, body weight, and environmental factors including climate changes and air pollutants could also play a role in PE. Several circulating cytoactive factors including anti-angiogenic factors and cytokines have also been associated with PE. Traditional midwifery care is a common practice in local maternity care units, while advanced perinatal care and new diagnostic tools such as uterine artery Doppler velocimetry have been useful in predicting early PE in major medical centers. These PE risk factors, early predictors and diagnostic tools vary vastly in different regions of the Eastern, Western and Developing world. Further understanding of the differences in the demographic, genetic, dietary and environmental factors among pregnant women in different world regions should help in designing a region-specific cluster of risk factors and predictors of PE, and in turn provide better guidance for region-specific tools for early detection and management of PE.

The Role of Interleukin-10 in the Pathophysiology of Preeclampsia

PURPOSE OF REVIEW

The pathophysiology of preeclampsia is complex and not entirely understood. A key feature in preeclampsia development is an immunological imbalance that shifts the maternal immune response from one of tolerance towards one promoting chronic inflammation and endothelial dysfunction. As a key regulator of immunity, IL-10 not only has immunomodulatory activity, but also directly benefits vasculature and promotes successful cellular interactions at the maternal-fetal interface. Here we focus on the mechanisms by which the dysregulation of IL-10 may contribute to the pathophysiology of preeclampsia.

RECENT FINDINGS

Dysregulation of IL-10 has been demonstrated in various animal models of preeclampsia. Decreased IL-10 production in both placenta and peripheral blood mononuclear cells has been reported in human studies, but with inconsistent results. The significance of IL-10 in preeclampsia has shifted from a key biomarker to one with therapeutic potential. As such, a better understanding of the role of this cytokine in the pathophysiology of preeclampsia is of paramount importance.

Interleukin-10 rs1800871 (-819C/T) and ATA haplotype are associated with preeclampsia in a Tunisian population

OBJECTIVES

Interleukin-10 (IL-10) is implicated in several aspects of pregnancy. As genetic predisposition can be involved in the development of preeclampsia, the association between IL-10's promoter region polymorphisms and this pathology has been investigated, although with conflicting results. To date, only a small cohort study (total n = 40) has evaluated this association in the African continent, and none have been conducted in Tunisia. Hence, we evaluated the association between these polymorphisms and the risk of preeclampsia in a large Tunisian cohort.

STUDY DESIGN

345 preeclampsia patients and 300 controls were genotyped for the IL-10 promoter region variants -1082A/G, -819C/T and -592A/C using real-time PCR.

MAIN OUTCOME MEASURES

Differences in means were determined by Student's t-test, while intergroup significance was assessed by Pearson χ² or 2-way ANOVA. Genotypes were tested for Hardy-Weinberg equilibrium (HWE) in the control and cases. Logistic regression analysis was performed in order to determine the odds ratios and 95% confidence intervals associated with the linkage disequilibrium risk.

RESULTS

An increased frequency of the -819 T (minor) allele and the -819 T/T genotype was seen in preeclampsia cases. Also, three-locus haplotype (-1082AG/-819CT/-592AC) analysis identified the ATA haplotype as having a higher incidence in women with preeclampsia (OR = 1.48, 95% CI: 1.03-2.11) and this was confirmed by multivariate regression analysis (OR = 1.65, 95% CI: 1.13-2.43) after controlling for covariates.

CONCLUSIONS

We suggest that the IL-10 -819 T/T variant and the ATA haplotype, which are associated with low production of IL 10, represent genetic risk factors for preeclampsia in Tunisian women.