Polymorphisms of interleukin-6, hepatic lipase and calpain-10 genes, and preeclampsia

Interleukin-6 (-174G/C), Interleukin-1β (-511 C/T), and Apolipoprotein B-100 (2488 C/T) Gene Polymorphism in Pre-Eclampsia

Background and objectives: Pre-eclampsia (PE) is a pregnancy-specific condition characterized by significant health risks for pregnant women worldwide due to its status as a multi-organ disorder. High blood pressure (hypertension) with or without proteinuria is usually considered an initial clinical sign of PE. The pathogenesis of pre-eclampsia is highly complex and likely involves multiple factors, including poorly developed uterine spiral arterioles, immunological issues, placental ischemia or infarction, and genetic abnormalities. Inflammatory cytokine production, regulated by cytokine gene polymorphisms, is one of the factors likely contributing to the development of PE. The present study aimed to assess IL-6, IL-1β, and Apo B-100 gene polymorphism and to evaluate the association of these polymorphisms with PE. Materials and Methods: This cross-sectional observational study involved 99 participants aged 16 to 45 years from Bahawal Victoria Hospital Bahawalpur, Punjab, Pakistan. The participants were divided into three groups: Group 1 (PE with severe hypertension), Group 2 (PE with hypertension), and Group 3 (control), each comprising 33 individuals. Maternal blood samples were collected, DNA was extracted, and molecular genetic analysis of the IL-6, IL-1β, and Apo B-100 genes was performed using the PCR-RFLP method. Allelic frequencies were compared, and statistical analysis was conducted using SPSS 25, applying the Hardy-Weinberg equation and chi-square test to evaluate the results. Results: There are differences in the distribution of allelic frequencies for IL-6 -174G/C (CC, GC, GG), IL-1β-511C/T (CC, CT, TT), and Apo B-100 2488 C/T (CC, CT, TT) between pre-eclamptic patients and the control group. The analysis using the Hardy-Weinberg equilibrium and chi-square test showed an association between the IL-6-174 G/C polymorphism and the severity of pre-eclampsia. Conclusions: The polymorphisms of the IL-6, IL-1β, and Apo B-100 genes revealed different alleles. The IL-6 gene alone was found to be in disequilibrium according to the Hardy-Weinberg equation, indicating a potential link to the severity of pre-eclampsia in the population studied.

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 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.

Interleukin-23 receptor (IL-23R) gene polymorphisms and haplotypes associated with the risk of preeclampsia: evidence from cross-sectional and in silico studies

PURPOSE

Pre-eclampsia is a relatively common pregnancy disorder. Serum concentrations of certain pro-inflammatory molecules and cytokines like interleukin-23 may affect the pathogenesis of pre-eclampsia. The interleukin-23 receptor (IL-23R) gene plays an important role in the progression of inflammatory and autoimmune diseases and IL-23 polymorphisms might influence the susceptibility of pre-eclampsia. The aim of the recent study was to establish the association between IL-23R gene polymorphisms and the susceptibility for developing of pre-eclampsia.

METHODS

One hundred and fifty-eight pregnant patients with pre-eclampsia and 153 controls were genotyped using RFLP-PCR and AS-PCR. Also, an in silico analysis was performed to predict possible effects of these variations on IL-23R mRNA and protein structures.

RESULTS

The frequency of the AG genotype of rs11209026 is related to a higher risk of pre-eclampsia. The mutant C and A allele in rs10889677 and rs11209026 SNPs, respectively, are correlated with the risk of pre-eclampsia and they are more frequent in severe late onset PE. We found higher frequency of the haplotype CG in patients with pre-eclampsia in comparison to healthy controls, as well as, the CG haplotype frequency significantly increased the risk of PE in severe, early onset, and late onset sub-groups. The results of computational analysis predicted rs11209026 and rs10889677 SNPs as functional variations, which can influence IL-23R mRNA and protein.

CONCLUSIONS

The results of present study show positive association between polymorphisms in the IL-23R gene and pre-eclampsia. Therefore, the presence of IL-23R rs11209026, rs10889677 polymorphism might be markers for the genetic susceptibility to pre-eclampsia.

Polymorphisms in Inflammatory Mediator Genes and Risk of Preeclampsia in Taiyuan, China

Excessive maternal inflammatory response is involved in the pathogenesis of preeclampsia. Few epidemiologic studies have investigated the associations between genetic variations in the inflammatory mediator genes and preeclampsia risk, and these studies have reached inconsistent results. We examined 31 single-nucleotide polymorphisms in IL-1A, IL-1B, IL-1R1, IL-2RA, IL-5RA, IL-6, IL-6R, TNFSF11, TNFRSF11A, IL-28RA, IRAK4, and KIT genes and the risk of preeclampsia and its clinical subtypes in a nested case-control study including 203 preeclampsia cases and 233 controls. We found that IL-1R1, IL-5RA, IL-6R, and TNFSF11 were associated with the risk of preeclampsia. Although the significant associations observed for preeclampsia overall were mainly seen for late-onset preeclampsia and severe preeclampsia, IL-6R (rs2229238) and TNFSF11 (rs9525643) polymorphisms were associated with the risk of early-onset preeclampsia. TNFSF11 (rs2200287 and rs2148072) polymorphisms were associated with risk of mild preeclampsia. Our study provided the first evidence that genetic variations in inflammatory mediator genes IL-1R1, IL-6R, TNFSF11, and IL-5RA were associated with preeclampsia risk, and the risk varied by preeclampsia subtypes.

Severe preeclampsia: association of genes polymorphisms and maternal cytokines production in Brazilian population

INTRODUCTION

Preeclampsia (PE) is a multi-system disorder of pregnancy characterized by hypertension and proteinuria. Healthy pregnancy is associated with a controlled inflammatory process, which is exacerbated in PE in response to excessive placental stimuli. Gene expression levels can affect inflammation and immune regulation. It is known that differences in cytokine allele frequencies amongst populations may contribute to difference in the incidence of several diseases.

OBJECTIVE

The aim of this study was to investigate the frequency of TNF-α, IL-6, IFN-γ and IL-10 genes polymorphisms and their relationship with the cytokines plasma levels in PE.

METHODS

A total of 281 women were included in this study; 116 with severe PE, 107 normotensive pregnant and 58 non-pregnant women. Cytokine genotyping was carried out by the polymerase chain reaction. The analyzed polymorphisms were: TNF-α (-308 G→A), IL-10 (-1082 G→A), IL-6 (-174 G→C), and IFN-γ (+874 A→T). Cytokine plasma levels were measured by Cytometric Bead Array method.

RESULTS

A higher frequency of the IFN-γ (+874) T/T genotype in severe PE comparing to normotensive pregnant women was found (P<0.001). TNF-α, IL-6 and IFN-γ plasma levels were higher in PE women compared to non-pregnant women (P<0.001; P<0.001; P=0.004). IL-6 and IFN-γ levels were also higher in PE women compared to normotensive pregnant (P<0.001; P=0.010). IL-10 levels were higher in normotensive pregnant women compared to PE (P<0.001). IFN-γ and IL-6 genes polymorphisms influenced the genic expression in PE and normotensive pregnant women, respectively.

CONCLUSIONS

These results suggest that IFN-γ seems to play a role in PE occurrence.

Analysis of polymorphisms in interleukin-10, interleukin-6, and interleukin-1 receptor antagonist in Mexican-Mestizo women with pre-eclampsia

Due to the fact that studies seeking associations of polymorphisms in regulatory regions of cytokine genes with pre-eclampsia (PE) have not always been consistent in different population analyses, the aim of this study was to investigate the possible association between rs1800896 of interleukin-10 (IL-10), rs1800795 of interleukin-6 (IL-6), and the variable number of tandem repeats (VNTR) in intron 2 of interleukin-1 receptor antagonist (IL-1Ra), as well as gene-gene interactions between these three polymorphisms with the presence of PE in Mexican-Mestizo women and one Amerindian population from México (Maya). A case-control study was performed where 411 pre-eclamptic cases and 613 controls were genotyped. For the rs1800896 of IL-10 and rs1800795 of IL-6, we used real-time polymerase chain reaction (PCR) allelic discrimination and for the VNTR of IL-1Ra, PCR. Allele frequency differences were assessed by Chi-squared test; logistic regression was used to test for associations; a gene-gene interaction was conducted. Genotypic and allelic distribution of the polymorphisms was similar in our population. The estimated of the gene-gene interaction between the polymorphisms did not differ significantly. However, we observed important differences in the distribution of the alleles and genotypes of the three polymorphisms analyzed between Mestiza-Mexicanas and Maya-Mestizo women. In conclusion, we did not find an association between polymorphisms in IL-10, IL-6, and IL-1Ra and PE in Mexican-Mestizo and Maya-Mestizo women. To our knowledge, this is the first time that these three polymorphisms were analyzed together with gene-gene interaction in women with PE.

Comparison of interleukin-6 levels in maternal and umbilical cord blood in early- and late-onset preeclampsia

PURPOSE

Increased inflammatory response and cytokines are claimed to play a significant role in the etiology of preeclampsia. Interleukin-6 (IL-6) is a proinflammatory cytokine. Limited number of studies evaluating IL-6 levels in preeclamptic patients have produced conflicting results. Therefore, the present study sought to compare maternal and umbilical cord serum levels of IL-6 in early- and late-onset preeclamptic pregnancies as well as in normal pregnancies.

MATERIALS AND METHODS

A total of 69 participants were enrolled in the study. The control group consisted of 24 participants with normal pregnancies. Preeclampsia group consisted of 45 participants. The preeclampsia group was further classified into the subgroups of early- and late-onset preeclampsia. Late-onset preeclampsia group consisted of 24 women whereas early-onset preeclampsia group consisted of 21 women. Serum and umbilical cord samples of IL-6 were compared.

RESULTS

There was no significant difference between maternal and umbilical cord serum IL-6 concentrations between the preeclampsia and control group. No significant difference was observed in maternal and umbilical cord serum IL-6 levels between early- and late-onset preeclampsia groups.

CONCLUSION

Our results do not support an increase in IL-6 levels in patients with early- and late-onset preeclampsia. The clinical relevance of our findings needs to be further investigated.

Genes and the preeclampsia syndrome

Preeclampsia is specific to pregnancy and is still a leading cause of maternal and perinatal mortality and morbidity, affecting about 3% of women, but the underlying pathogenetic mechanisms still remain unclear. Immune maladaptation, placental ischemia and increased oxidative stress represent the main components discussed to be of etiologic importance, and they all may have genetic implications. Since the familial nature of preeclampsia is known for many years, extensive research on the genetic contribution to the pathogenesis of this severe pregnancy disorder has been performed. In this review, we will overview the linkage and candidate gene studies carried out so far as well as summarize important historical notes on the genetic hypotheses generated in preeclampsia research. Moreover, the influence of maternal and fetal genes and their interaction as well as the role of genomic imprinting in preeclampsia will be discussed.

Absence of an association of tumor necrosis factor (TNF)-alpha G308A, interleukin-6 (IL-6) G174C and interleukin-10 (IL-10) G1082A polymorphism in women with preeclampsia

OBJECTIVE

TNF-alpha G308A, IL-6 G174C and IL-10 G1082A polymorphisms have recently been associated with preeclampsia (PE). The aim of this study was to clarify whether the occurrence of TNF-alpha, IL-6 and IL-10 polymorphisms is increased in women of our population with PE in a previous pregnancy.

METHODS

A retrospective, controlled, open, multicenter study was carried out in 107 women with a history of PE and 107 women with uncomplicated pregnancies. Smears from buccal gingival cells were analyzed for the polymorphisms of TNF-alpha, IL-6 and IL-10 by hybridization on microarrays. Statistical significance was calculated by the chi-quadrant test.

RESULTS

Heterozygocity for the gene polymorphisms did not occur more often in preeclamptic women compared with controls (TNF-alpha: 29.0% versus 24.3%, p>0.05; IL-6: 46.7% versus 51.4%, p>0.05; or IL-10: 49.5% in each). Moreover, there was no significant difference between preeclamptics and controls with regard to homozygocity for TNF alpha (1.9% versus 3.7%, p>0.05); IL-6 (17.8% versus 13.1%, p>0.05); and IL-10 (30.8% versus 32.7%, p>0.05).

CONCLUSION

In contrast to the findings of some other investigators, gene polymorphisms do not seem to be important in our population for development of PE.

Inflammatory Changes in Preeclampsia: Current Understanding of the Maternal Innate and Adaptive Immune Response

Preeclampsia is characterized by generalized endothelial dysfunction as a result of an inappropriate maternal immune response against the fetus. It has been postulated that the adaptive immune system plays a key role in the etiology of preeclampsia by generating a pro-inflammatory Th1 type immune reaction. In this review, recent studies on Th1 and Th2 type cytokine mapping in preeclampsia are reviewed, as well as on the sources of pro-inflammatory cytokines and the role of regulatory cytokines and chemokines. In addition, we discuss the possible role of Toll-like receptors of the innate immune system in the pathophysiology of preeclampsia.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to summarize the newer concepts related to the pathogenesis of preeclampsia and explain the role of the maternal immune system and the role of pro-inflammatory and regulatory cytokines and chemokines in the pathophysiology of the disease.