No association of the genetic polymorphisms of endothelial nitric oxide synthase, dimethylarginine dimethylaminohydrolase, and vascular endothelial growth factor with preeclampsia in Korean populations

Association of endothelial nitric oxide synthase gene variants in pre-eclampsia: an updated systematic review and meta-analysis

INTRODUCTION

Three common endothelial nitric oxide synthase (eNOS) gene variants are existed such as; G-894T, T-786C, and variable number tandem repeats in intron-4 (VNTR intron-4) which has been proposed to be linked with PE. However, there is still debate regarding the findings. To address this, a review was conducted to assess the potential association of eNOS gene variants at these positions with the risk of PE.

METHODS

PubMed, Scopus, Science Direct, Hinari, and African Journal Online databases and Google Scholar search engines were utilized to search studies published in English-language until 30 January 2023. The Joanna Briggs Institute Meta-Analysis instrument was used for data extraction process and the Newcastle-Ottawa Scale was used to appraise the quality of the included studies. Meta-regression analysis was conducted using Stata 14 statistical software. The pooled odds ratios (ORs) of fixed and random effect models were utilized to evaluate the association of eNOS gene polymorphism with the risk of PE at 95% CI. Publication bias was assessed using Egger's test and a funnel plot.

RESULTS

The study included 47 observational studies involving 13,795 pregnant women (6216 cases and 7579 controls). Pregnant women carrying TT and CC genotypes of eNOS gene at 894 and 786 positions were found to have a greater probability of developing PE as compared to GG and TT genotypes (OR = 1.54 vs. 1.43 and CI: 1.12 - 2.14 vs.1.02 - 2.00 at 95% CI), respectively. However, a significant association was not observed between aa genotype of eNOS gene in VNTR intron-4 region and risk of PE as compared to bb genotype (OR =1.26, 95% CI: 0.83 - 1.89). The allelic model of eNOS gene at all positions showed nonsignificant association with the risk of PE.

CONCLUSIONS

The women having eNOS gene variants at 894 and 786 positions showed a significant association with the risk of PE. Yet, the women having eNOS gene variant at intron-4 region showed nonsignificant association with the risk of PE. Thus, this study suggests that eNOS gene variants may play a role in the development of PE, but large-scale studies are required to inaugurate concrete evidence on the roles of eNOS gene variants in PE pathogenesis.

The eNOS-G894T genetic polymorphism and risk of preeclampsia: A case-control study, an updated meta-analysis, and a bioinformatic assay

OBJECTIVES

Preeclampsia (PE) is a leading cause of maternal death worldwide and involves vascular endothelial dysfunction. The aim of this study was to investigate the association of the G894T polymorphism in the endothelial nitric oxide synthase (eNOS) gene and the risk of preeclampsia in a case-control design in an Iranian population, which was followed by a meta-analysis and an in silico approach.

METHODS

In the case-control study, 300 people including 135 pregnant women with preeclampsia and 165 healthy pregnant women were included. The genotype of G894T polymorphism was determined by the PCR-RFLP method. We searched authoritative scientific databases to find eligible studies for meta-analysis. The odds ratio with a 95% confidence interval was estimated to find the strength of the association of the mentioned polymorphism with the risk of preeclampsia. In addition, the effect of G894T transversion on eNOS gene function was evaluated by some bioinformatics tools.

RESULTS

Our case-control data showed that the G894T polymorphism is associated with an increased risk of preeclampsia. In the meta-analysis, 33 eligible studies were included, and the results showed that the G894T polymorphism is associated with an increased risk of preeclampsia in the overall analysis and some stratified analyses. In addition, the structural analysis showed that the G894T variant can affect the splicing process as well as the protein stability.

CONCLUSIONS

Based on the results, the aforementioned polymorphism may be a risk factor for preeclampsia and could be considered a potential molecular biomarker for screening susceptible individuals.

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.

Associations between AGT, MTHFR, and VEGF gene polymorphisms and preeclampsia in the Chinese population

INTRODUCTION

Preeclampsia (PE) is a pregnancy-specific multisystemic syndrome. This study aimed to investigate the associations between angiotensinogen (AGT), methylenetetrahydrofolate reductase (MTHFR), vascular endothelial growth factor (VEGF) polymorphisms, and PE in the Han Chinese population.

METHODS

We genotyped 26 single-nucleotide polymorphisms (SNP) in three genes by using QuantStudio™ 12 K Flex Real-Time PCR technology in 168 patients with PE and 204 healthy pregnant control subjects. The associations of tested polymorphisms with PE were analyzed at allele, genotype, and haplotype levels.

RESULTS

A common coding variant in MTHFR, rs2274976, was significantly associated with increased risk of PE in both allelic and genotype models (P < 0.05). The heterozygous genotypes of rs699 (G/A vs G/G) in AGT gene and rs3025035 (C/T vs C/C) in VEGF gene showed weak associations with increased PE risk, whereas the mutant homozygous genotype of rs3024987 (TT vs C/C) and the heterozygous genotype of rs3025039 (C/T vs C/C) in VEGF gene displayed weak associations with decreased PE risk (P < 0.05).

DISCUSSION

However, these weak associations lost significance after multiple testing correction. The results indicated that rs2274976 in MTHFR gene may contribute to the increased risk of PE in pregnant women. AGT and VEGF gene polymorphisms may not play a significant role in PE development.

Association of Endothelial Nitric Oxide Synthase 894G > T Polymorphism with Preeclampsia Risk: A Systematic Review and Meta-Analysis based on 35 Studies

Several case-control studies have been performed to investigate the association between 894 G > T polymorphism in endothelial nitric oxide synthase (eNOS) gene and susceptibility to preeclampsia. However, the results were inconsistent and inconclusive. Therefore, we conducted this meta-analysis to investigate the association. Methods: All studies published up to September 30, 2019 were identified by searching electronic databases such as PubMed, EMBASE, CNKI, and WANFANG. Results: A total of 35 case- control studies with 4,254 cases and 5,801 controls were selected. There was a significant association between the eNOS 894 G > T and preeclampsia risk. When stratified by ethnicity, an increased risk of preeclampsia was found in Caucasian and Mixed populations, but not in Asians or Africans. Conclusion: Based on our meta-analysis, the eNOS 894 G > T polymorphism was associated with an increased risk of preeclampsia, especially among Caucasian and Mixed populations.

Association of endothelial nitric oxide synthase gene variants with preeclampsia

Background

Preeclampsia (PE) is a complex pregnancy hypertensive disorder with multifaceted etiology. The endothelial nitric oxide synthase (eNOS) gene and nitric oxide (NO) levels has been reported to be associated with PE predisposition in various populations. Therefore, present study was designed to investigate the role of NO levels and eNOS gene variants in preeclamptic women in Pakistan.

Methods

A total of 600 women were evaluated, 188 of PE with mild features, 112 of PE with severe features and 300 normotensive pregnant women. NO levels were detected by Greiss reaction method and genotyping following sequencing was conducted for eNOS gene variants. Further insilico studies were performed to get insights into the structural and functional impact of identifies mutation on eNOS protein as well as on protein regulation.

Results

Reduced concentrations of NO were reported in all PE groups (p < 0.05) as compared to controls. The frequency of c.894 T (p.298Asp) and g.-786C alleles were significantly associated with PE. In addition, novel homozygous variant g.2051G > A was also significantly associated with PE when compared to normotensive women. Dynamic simulation studies revealed that Glu298Asp mutation destabilize the protein molecule and decrease the overall stability of eNOS protein. Molecular docking analysis of mutant promoter with transcription factors STAT3 and STAT6 proposed changes in protein regulation upon these reported mutations in upstream region of the gene.

Conclusion

Considering the results of current study, the functional alterations induced by these variants may influence the bioavailability of NO and represents a genetic risk factor for increased susceptibility to PE. However, large studies or meta-analysis are necessary to validate these findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12978-021-01213-9.

Preeclampsia (PE) is a complex pregnancy hypertensive disorder with multifaceted etiology characterized by increased hypertension and proteinuria after 20 weeks of gestation. The present study was directed to determine the role of eNOS in susceptibility to PE and the association of c.894G > T (p.(Glu298Asp), intron 4b/4a, g.-786 T > C and other possible variants of eNOS gene with preeclampsia in Pakistani population. Computational analysis of identified variants in the coding and non-coding region of the eNOS gene was also conducted to determine the change in gene regulation and further protein stability. A total of 600 women were evaluated, 188 with mild and 112 with PE with severe features PE with 300 normotensive pregnant women. NO levels and genotyping following sequencing was conducted for eNOS gene variants. Further insilico studies were performed to get insights into the structural and functional impact of identifies mutation on eNOS protein as well as on protein regulation. Data from the current study suggest that there might be other risk variants of the eNOS gene (g.2051G > A and g.1861G > A) and lower levels of serum NO that confers in an increased risk of PE. The detailed computational investigation further confirmed the deformities and changes in protein flexibility upon Glu298Asp. These structural alterations might be associated with preeclampsia. Variants in the promoter region of the eNOS gene further validate the change in gene regulation for the onset of disease. Identification of key structural and functional features in eNOS protein and gene regulatory region might be used for designing specific drugs for therapeutic purpose.

Association Between Endothelial Nitric Oxide Synthase (eNOS) -786 T/C and 27-bp VNTR 4b/a Polymorphisms and Preeclampsia Development

The aim of the present study was to analyze the distribution of genotypes and haplotypes of functional eNOS gene polymorphisms in the promoter (-786 T/C), intron 4 (VNTR4b/a) and exon 7 (894 G/T), in Serbian population of pregnant women, and establish a possible association between these polymorphisms and preeclampsia development. DNA was isolated from venous blood samples of 50 heathy pregnant women and 50 preeclampsia patients. Polymerase Chain Reaction/Restriction Fragment Length Polymorphism (PCR/RFLP) technique, with appropriate sets of primers and specific restriction enzymes, was used to determine polymorphisms in eNOS gene. Statistical analysis was done using the SPSS and HAPLOVIEW software packages. eNOS -786 T/C polymorphism was significantly associated with preeclampsia (P = 0.006). Homozygotes for the VNTR polymorphism had also an elevated risk of developing preeclampsia (OR=7.68, 95%CI (0.89-65.98)), especially the mild (OR=9.33, 95%CI (0.98-88.57)) and late form (OR=8.52, 95%CI (0.90-80.58)). The 894 G/T polymorphism was not associated with preeclampsia. "G-C-b" and "T-4a-T" haplotypes were more frequent in preeclampsia, though without reaching statistical significance. -786 T/C and VNTR 4b/a eNOS gene polymorphisms were associated with preeclampsia risk in Serbian patients.

A meta-analysis of the vascular endothelial growth factor polymorphisms associated with the risk of pre-eclampsia

Backgroud: Pre-eclampsia (PE) is a common pregnancy-induced hypertension disease. Some case–control studies reported the association between vascular endothelial growth factor (VEGF) gene polymorphisms (rs3025039, rs2010963) and PE risk. However, these associations were inconsistent in several studies. Therefore, we conducted this meta-analysis to assess the role of VEGF gene polymorphisms in PE more precisely.

Methods: Eligible studies were searched in PubMed, Embase, Web of Science and Chinese (Chinese National Knowledge Infrastructure (CNKI) and WanFang) databases. Statistical analyses were performed by Stata 12.0 software. Odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of the association. In addition, subgroup analyses, sensitive analyses and publication bias analyses were performed to further assess this meta-analysis.

Results: In total, 21 studies were included in the meta-analysis covering 2018 cases and 2632 controls. There were significant associations between VEGF polymorphisms (rs3025039, rs2010963) and PE risk in the overall populations. In the subgroup analyses, we found that rs3025039 polymorphism was associated with the increased risk of PE among Chinese. As for rs2010963 polymorphism, a significant association was observed in subgroup of Caucasian.

Conclusion: The present study suggested that the two VEGF gene polymorphisms (rs3025039, rs2010963) are associated with increased risk of PE in different ethnic groups, which means that the targets may be useful genetic markers for early prediction of PE.

Genetic markers for preeclampsia in Peruvian women

BACKGROUND

Preeclampsia is a multiorgan disorder associated with maternal and perinatal morbi-mortality. In Peru, incidence is 10% and accounts for 22% of maternal deaths. Genome and genetic epidemiological studies have found an association between preeclampsia and genetic polymorphisms.

OBJECTIVE

To determine the association of the vascular endothelial growth factor (VEGF) +936 C/T and +405 G/C, interleukine-6 (IL-6) -174 G/C, IL-1β-511 C/T, Apo A-1-75 G/A, Apo B-100 2488 C/T (Xbal) polymorphisms with preeclampsia in pregnant Peruvian women.

METHODS

Were included preeclamptic and healthy (control) pregnant women. Maternal blood samples were subjected to DNA extraction, and molecular genetic analysis was conducted using the PCR-RFLP technique and following a specific protocol for each gene. Allele and genotypic frequencies in the cases and controls were compared.

RESULTS

No association was found between the VEGF+936C/T and VEGF+405 polymorphisms and preeclampsia. The frequencies of the GG genotypes and the G allele of the -174 G/C polymorphism in the IL6 gene in preeclamptic and controls showed significant differences, with higher frequencies in cases. For the -511 C/T polymorphism of the IL-1β gene, no significant differences were found in the frequencies of TT genotypes compared with CT+CC. The genotypes and alleles of the Apo-A1-75 G/A and Apo-B100 Xbal variants showed no significant differences between cases and controls.

CONCLUSION

No association was found between the studied genetic markers and preeclampsia. However, in the -174G/C polymorphism of the IL-6 gene, significant differences were found mainly in the GG genotype and G allele.

MTHFR and F5 genetic variations have association with preeclampsia in Pakistani patients: a case control study

BACKGROUND

To study the role of single nucleotide variants (SNVs) of genes related to preeclampsia in Pakistani pregnant women.

METHODS

After ethical approval and getting informed consent; 250 pregnant women were enrolled and equally divided into two groups (125 preeclamptic cases and 125 normotensive pregnant women). Demographic details and medical history were recorded, and 10 ml blood sample was obtained for DNA extraction. The tetra-primer amplification refractory mutation system (ARMS) assays were developed for assessing the variants of three preeclampsia related genes; F5, MTHFR and VEGFA. An association of six SNVs; F5:c.1601G > A (rs6025), F5:c.6665A > G (rs6027), MTHFR: c.665C > T (rs1801133), MTHFR: c.1286A > C (rs1801131), VEGFA: c.-2055A > C (rs699947) and VEGFA: c.*237C > T (rs3025039) with preeclampsia was determined by using different genetic models.

RESULTS

Genotyping of the SNVs revealed that patients with MTHFR:c.665C > T, have increased susceptibility to preeclampsia (CT versus CC/TT: OR = 2.79, 95% CI = 1.18-6.59; P* = 0.046 and CT/TT vs CC: OR = 2.91, 95% CI = 1.29-6.57; P* = 0.0497, in overdominant and dominant models, respectively), whereas F5:c.6665A > G, (A/G vs AA/GG: OR = 0.42, 95% CI = 0.21-0.84; P* = 0.038 in overdominant model) and MTHFR:c.1286A > C, (CC versus AA: OR = 0.36, 95% CI = 0.18-0.72; P* = 0.0392 in codominant model) have significantly decreased risk for preeclampsia. F5:c.1601G > A, VEGFA: c.-2055A > C and VEGFA: c.*237C > T variants revealed no relationship with the disease.

CONCLUSION

This is the first case control study describing the protective role of F5:c.6665A > G against preeclampsia in any world population. In addition, the present study confirmed the association and role of MTHFR gene variations in the development of preeclampsia in Pakistani patients. Further genetic studies may be required to better understand the complex genetic mechanism of SNVs in preeclampsia related genes in pregnant women.

Association between Vascular Endothelial Growth Factor Gene Polymorphisms and Pre-Eclampsia Susceptibility: An Updated Meta-Analysis

Objectives: The aim of this study was to assess the genetic association between vascular endothelial growth factor (VEGF) gene polymorphisms and the risk of pre-eclampsia (PE).Methods: A systematic literature search of several databases (PubMed, Embase, and the China National Knowledge Infrastructure (CNKI)) was conducted for case-control trials comparing VEGF polymorphisms (+936C/T, -634G/C, -2578C/A, and -1154G/A) with the risk of PE. Meta-analysis was performed using the Stata 12.0 software.Results: Twenty-three case-control studies on a total of 2597 PE patients and 3075 controls were included in our meta-analysis. The +936C/T polymorphism was observed to be associated with the risk of PE in the overall population (T vs. C: odds ratios (OR) = 1.434, 95% confidence interval (CI) = 1.120-1.836, P = .004). However, the -634G/C, -2578C/A, and -1154G/A polymorphisms showed no association with the risk of PE. A subgroup analysis based on ethnicity found that the +936C/T polymorphism was associated with the risk of PE in both Europeans and Asians. Furthermore, the -634G/C polymorphism was found to be associated with the risk of PE in Europeans (C vs. G: OR = 1.428, 95% CI = 1.141-1.778, P = .002). The polymorphisms at other loci were not associated with the risk of PE.Conclusion: This meta-analysis suggests that VEGF +936C/T polymorphism, rather than -634G/C, -2578C/A, or -1154G/A polymorphisms, is associated with the risk of PE in the overall study population. However, the -634G/C polymorphism may be associated with the risk of developing PE in Europeans.

Vascular endothelial growth factor single nucleotide polymorphisms and haplotypes in pre-eclampsia: A case-control study

An association between vascular endothelial growth factor (VEGFA) gene variants and altered VEGF secretion and preeclampsia (PE) were described, often with inconclusive findings. An ethnic contribution to the association of VEGFA polymorphisms with PE and its associated features was also suggested. To investigate whether common VEGFA single nucleotide polymorphisms (SNP) are linked with PE and associated features in Tunisian women. A case-control study involving 300 women with PE, and 300 age-matched control women. Genotyping of VEGFA rs833052, rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068, rs833070, rs3025020, and rs3025039SNPs was done by real-time PCR. Minor allele frequency (MAF) of rs833052, rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068, rs833070, rs3025020, and rs3025039 VEGFA SNP, were not significantly different between PE cases and control women. In addition, there was lack of association of the genotypes of VEGFA SNPs with PE, irrespective of the genetic model used. Seven-locus (rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068 and rs833070) haplotype analysis demonstrated positive association of ATGCCAA, ACAGCAG and CCAGCGG, and negative association of CCAGCAA and ATGCCGG haplotypes with PE, all of which except for ACAGCAG remained associated with PE after correcting for multiple comparisons. Increased and reduced PE severity was associated with ATGCCAA, and with ATGCCGG and CCAGCAA haplotypes, respectively. Furthermore, carriage of CCGGTAG haplotype was associated with reduced risk of PE. Our study suggests that VEGFA haplotypes, more so than individual SNPs, play a role in PE pathogenesis in Tunisian women. These findings need confirmation in other ethnic populations.

Association of common eNOS/NOS3 polymorphisms with preeclampsia in Tunisian Arabs

We investigated the association of endothelial nitric oxide synthase (NOS3) polymorphisms -786T>C, 27-bp repeat 4b/4a, and Glu298Asp with preeclampsia (PE). This was a case-control study involving 345 unrelated Tunisian women with PE and 289 unrelated age- and ethnically matched control women. The -786C allele was significantly increased in PA patients when compared to healthy controls (P=0.015). In contrast, MAF of Glu298Asp (P=0.103) and 4b/4a (P=0.168) were not significantly different between the study groups. Higher frequencies of heterozygous Glu298/298Asp and homozygous -786T/-786T genotypes were seen in PE cases compared to healthy subjects. The combination of genotypes 221 (-786T>C, Glu298Asp, 4a/4a) was more in PE cases compared with control women (17.68% vs. 8.36%; P=0.029). Multivariate regression analysis confirmed this association. Genetic variation at the NOS3 locus represents a genetic risk factor for increased susceptibility to PE.

Association of endothelial nitric oxide synthase gene G894T polymorphism and serum nitric oxide levels in patients with preeclampsia and gestational hypertension

OBJECTIVE

Pregnancy-induced hypertension is one of the most important cause of maternal-fetal morbidity and mortality. Pregnancy-related hypertensive disorders are usually associated with diminished nitric oxide (NO) levels. We aimed to evaluate the role of serum NO levels and eNOS gene G894T polymorphism on hypertensive disorders of pregnancy.

METHODS

Eighty patients with gestational hypertension or preeclampsia, and 80 healthy pregnants were enrolled to analyze serum NO levels and G894T polymorphism of the eNOS gene. NO level was analyzed by high-performance liquid chromatography (HPLC) method. The G894T polymorphism of the eNOS gene was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).

RESULTS

There was no significant difference between groups in terms of G894T/eNOS genotype and allele frequencies (p > 0.05). Serum NO levels were significantly lower in the patients group. In the control group, subjects with thymine-thymine (TT) genotype had significantly lower NO levels when compared to subjects with guanine-guanine (GG) or guanine-thymine (GT) genotype (p < 0.05).

CONCLUSIONS

We failed to demonstrate an association between eNOS gene G894T polymorphism and serum NO levels in patients with pregnancy-induced hypertensive disorders. We established a relation between pregnancy-induced hypertension and low NO levels.

Protective role of DDAH2 (rs805304) gene polymorphism in patients with myocardial infarction

The purpose of the present study was to establish the role of DDAH gene polymorphisms in the risk of developing myocardial infarction (MI) in a clinical cohort of Mexican patients. One polymorphism (rs1498373) in the DDAH1 and three in the DDAH2 (rs805304, rs3131383, and rs805305) genes were performed by TaqMan genotyping assays in 473 patients with MI and 447 healthy unrelated controls. Similar distribution of DDAH1 and DDAH2 polymorphisms was observed in MI patients and healthy controls. Under a recessive model adjusted for age, gender, and obesity, the rs805304 C allele was associated with decreased risk of MI (OR = 0.70, 95% CI = 0.51-0.96, P = 0.030). The effect of the polymorphisms on various cardiovascular risk factors was analyzed. Under a recessive model adjusted for age and gender, the DDAH2 rs805304 C allele was associated with decreased risk of obesity (OR = 0.35, 95% CI = 0.22-0.57, P = 0.001). The three DDAH2 polymorphisms were in strong linkage disequilibrium. Our results suggest that the rs805304 C allele was associated with decreased risk of MI and decreased risk of obesity.

Vascular endothelial growth factor +936C/T, -634G/C, -2578C/A, and -1154G/A polymorphisms with risk of preeclampsia: a meta-analysis

BACKGROUND

Emerging evidence showed that VEGF gene polymorphisms are involved in the regulation of VEGF protein expression, thus increasing an individual's susceptibility to preeclampsia (PE); but individually published results are inconclusive. The aim of this meta-analysis was to investigate the associations between VEGF gene polymorphisms and PE risk.

METHODS

A systematic literature search of MEDLINE, Embase, Web of Science, and CNKI (Chinese National Knowledge Infrastructure) databases was conducted. Statistical analyses were performed using STATA 12.0 software and Review manager 5.1. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

RESULTS

According to the inclusion criteria, 11 case-control studies were finally included in this meta-analysis. A total of 1,069 PE cases and 1,315 controls were included in this study. Our meta-analysis indicated that VEGF +936C/T (T vs. C, OR = 1.52, 95%CI = 1.08-2.12) or -634G/C polymorphism (C vs. G, OR = 1.24, 95% CI = 1.03-1.50) was associated with the risk of PE, whereas there was no association between -2578C/A (A vs. C, OR = 0.98, 95%CI = 0.82-1.16) or -1154G/A (A vs. G, OR = 1.30, 95%CI = 0.94-1.78) polymorphism and PE risk in our study.

CONCLUSION

Our meta-analysis suggested that VEGF -2578C/A or -1154G/A polymorphism had no association with PE risk in all examined patients, whereas there was an association between VEGF +936C/T or -634G/C polymorphism and risk of PE.

Associations between vascular endothelial growth factor gene polymorphisms and pre-eclampsia susceptibility: a meta-analysis

OBJECTIVE

The aim of this study was to assess whether vascular endothelial growth factor (VEGF) polymorphisms are associated with susceptibility to pre-eclampsia.

METHODS

A meta-analysis was conducted on the associations between the -634 C/G, +936 C/T, -1154 A/G, and -2578 A/C polymorphisms of VEGF and pre-eclampsia.

RESULTS

Ten studies involving 2068 subjects (pre-eclampsia, 950; controls, 1118) were included in the meta-analysis. The meta-analysis revealed an association between pre-eclampsia and the VEGF -634 C allele in overall group (OR = 1.351, 95% CI = 1.105-1.651, p = 0.003) and in European group (OR = 1.427, 95% CI = 1.139-1.787, p = 0.002). The meta-analysis revealed an association between pre-eclampsia and the VEGF -936 T allele in Asians, but not in Europeans (OR = 1.555, 95% CI = 1.232-1.961, p = 1.9 × 10(-5); OR = 1.587, 95% CI = 0.933-2.699, p = 0.088). However, the meta-analysis revealed no association between pre-eclampsia and the VEGF -1154 A/G and 2578 A/C polymorphisms

CONCLUSIONS

This meta-analysis suggested that the VEGF -634 C/G polymorphism is associated with susceptibility to pre-eclampsia in Europeans and that the VEGF -634 C/G polymorphism is associated with pre-eclampsia in Asians.

The polymorphism for endothelial nitric oxide synthase gene, the level of nitric oxide and the risk for pre-eclampsia: a meta-analysis

Endothelial NO, which is synthesized by endothelial nitric oxide synthase (eNOS), has been reported to be related with the occurrence of pre-eclampsia (PE). However, the polymorphisms of eNOS (-786 T>C, 4b/a and G894T), the level of nitric oxide and the risk of PE remain unclear. Thus we performed this meta-analysis to determine the associations between them in order to predict the risk for PE and interference with PE development in the early period of antenatal care. All studies investigating the associations between PE risk and polymorphisms of eNOS, or PE risk and serum concentration of NO were reviewed. Finally, 29 studies were included, involving 11 for -786 T>C, 11 for 4b/a, and 22 for G894T polymorphisms and PE risk. In the overall analysis, -786 T>C polymorphism was found to be related with increased PE risk in the dominant model (OR=1.17, 95% CI=1.02-1.35). a allele for 4b/a suffers the high risk of PE (OR=1.46, 95% CI=1.01-2.10). In the subgroup analysis, significantly increased risk was detected among Europeans for -786 T>C polymorphism (OR=1.40, 95%CI=1.14-1.73).However, no significant association was detected for G894T polymorphism in the overall and subgroup analysis. The comprehensive evaluation of 9 available studies indicated that serum NO level was significantly decreased in case group (SMD=-0.96 umol/mL, 95%CI=-1.80, -0.12 umol/mL).Hence, we concluded that eNOS gene -786 T>C and 4b/a except for G894T polymorphisms were contributed significantly to PE risk, especially for Europeans, and a low NO concentration in serum increased the risk for PE.

Roles of nitric oxide and asymmetric dimethylarginine in pregnancy and fetal programming

Nitric oxide (NO) regulates placental blood flow and actively participates in trophoblast invasion and placental development. Asymmetric dimethylarginine (ADMA) can inhibit NO synthase, which generates NO. ADMA has been associated with uterine artery flow disturbances such as preeclampsia. Substantial experimental evidence has reliably supported the hypothesis that an adverse in utero environment plays a role in postnatal physiological and pathophysiological programming. Growing evidence suggests that the placental nitrergic system is involved in epigenetic fetal programming. In this review, we discuss the roles of NO and ADMA in normal and compromised pregnancies as well as the link between placental insufficiency and epigenetic fetal programming.

No association between polymorphisms/haplotypes of the vascular endothelial growth factor gene and preeclampsia

BACKGROUND

Preeclampsia (PE) is the first worldwide cause of death in pregnant women, intra-uterine growth retardation, and fetal prematurity. Some vascular endothelial grown factor gene (VEGF) polymorphisms have been associated to PE and other pregnancy disturbances. We evaluated the associations between VEGF genotypes/haplotypes and PE in Mexican women.

METHODS

164 pregnant women were enrolled in a case-control study (78 cases and 86 normotensive pregnant controls). The rs699947 (-2578C/A), rs1570360 (-1154G/A), rs2010963 (+405G/C), and rs25648 (-7C/T), VEGF variants were discriminated using Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR-RFLP) methods or Taqman single nucleotide polymorphism (SNP) assays.

RESULTS

The proportions of the minor allele for rs699947, rs1570360, rs2010963, and rs25648 VEGF SNPs were 0.33, 0.2, 0.39, and 0.17 in controls, and 0.39, 0.23, 0.41, and 0.15 in cases, respectively (P values > 0.05). The most frequent haplotypes of rs699947, rs1570360, rs2010963, and rs25648 VEGF SNPs, were C-G-C-C and C-G-G-C with frequencies of 0.39, 0.21 in cases and 0.37, 0.25 in controls, respectively (P values > 0.05)

CONCLUSION

There was no evidence of an association between VEGF alleles, genotypes, or haplotypes frequencies and PE in our study.

Genetic variants, endothelial function, and risk of preeclampsia among American Indians

OBJECTIVE

To determine the prevalence in an American Indian population of genetic variants with putative effects on endothelial function and determine whether they are associated with preeclampsia.

METHODS

Five genetic polymorphisms potentially related to endothelial function in the NOS3, GNB3, and DDAH1 genes were genotyped from a total of 101 cases, 198 controls, and an additional 110 population-based controls among an American Indian population.

RESULTS

The minor allele frequencies for NOS3 (rs1799983, rs3918227), GNB3 (rs5442), and DDAH1 (rs10158674, rs233115) among those with and without PE in this population were 25, 10, 5, 11, and 30%, respectively. Although not statistically significant, the maximum risk associated with any of these SNPs was 2.22 (0.734-6.73, 95% CI, p = 0.156) in a multivariate analysis of the A allele of the rs233115 SNP incorporated in a recessive model.

CONCLUSION

Although endothelial dysfunction likely plays a role in the pathophysiology of PE, this study was unable to find evidence for an association between these five SNPs on three genes influencing endothelial function and PE. This may be due to insufficient power to detect an association, investigation of SNPs without linkage to risk of PE in this population or other factors. Investigation of additional SNPs in these or related genes and other populations seems warranted.

The significance of -786T > C polymorphism of endothelial NO synthase (eNOS) gene in severe preeclampsia

OBJECTIVE

Preeclampsia (PE) is believed to be induced by endothelial cell dysfunction in placenta. Highly polymorphic endothelial nitric oxide synthase (eNOS) activity belongs to the factors significantly influencing vaso-motor tone in placenta and PE susceptibility. The aim of this study was to evaluate prevalence of -786T/C polymorphism of eNOS gene in the groups of women with mild and severe PE.

STUDY DESIGN

The study was performed in the group of 218 preeclamptic (including 136 with severe PE) and of 400 normotensive healthy women delivered normally after a healthy gestation. The eNOS -786T/C polymorphism was determined using PCR/RFLP assay. Additionally, detailed correlation between eNOS genotypes and clinical/laboratory data in the PE group has been analyzed.

RESULTS

The higher frequency of mutated homozygous CC genotypes (17.4% vs. 11.5% in controls, OR 1.62, n.s.) and of C alleles (allelic frequency 44.1 vs. 36.6%; OR 1.36, p = 0.012) in the group of PE has been determined. Furthermore, in the group of severe PE the overrepresentation of mutated CC genotypes (23.5% vs. 11.5%, OR 2.37, p = 0.0014) and mutated C alleles (47.8 vs. 36.6%, OR 1.58, p = 0.0016) has been found.

CONCLUSIONS

The presence of mutated homozygous CC genotype and C allele of -786T/C polymorphism of eNOS gene influences the higher susceptibility to develop severe PE development.

Menstrual abnormalities and predisposition to pregnancy-related hypertensive disorders: a retrospective study

OBJECTIVE

Pregnancy-related hypertensive disorders (PRHDs) are a leading cause of maternal and perinatal morbidity and mortality in developed countries. This study investigated a possible association of PRHDs with menstrual abnormalities.

MATERIALS AND METHODS

We contacted all women with PRHDs who delivered in our clinic between 2004 and 2007 as well as a random control cohort without pregnancy complications and asked them about their menstrual cycle characteristics. Statistical analyses were performed using R, with significance set at p < 0.05.

RESULTS

We collected data for 237 women with normal pregnancies and 255 women with PRHDs, among whom 143 had gestational hypertension and 70 had mild and 41 severe preeclampsia. By monovariate analysis, PRHDs correlated with dysmenorrhoea, hypermenorrhoea and menstrual irregularity (p < 0.05). By multivariate analysis, the occurrence of PRHDs was influenced by dysmenorrhoea and menstrual irregularity (p < 0.05).

CONCLUSIONS

PRHDs usually affect women with painful or irregular menstrual cycles, perhaps due to metabolic syndrome or molecular pathways involving vasoactive substances, with clear vascular implications.

Endothelial nitric oxide synthase, angiotensin-converting enzyme and angiotensinogen gene polymorphisms in hypertensive disorders of pregnancy

We investigated the variations in genes encoding endothelial nitric oxide synthase (NOS3), angiotensin-converting enzyme (ACE) and angiotensinogen (AGT) in hypertensive disorders of pregnancy and the relationship between the polymorphisms and circulating nitric oxide (NO) and ACE levels in pregnant north Indian women. Frequencies of NOS3 G894T, 4b/a and T(-786) --> C, AGT T704C and ACE ins/del polymorphisms were studied in 342 subjects: 120 with preeclampsia (PE), 104 with gestational hypertension and 118 normotensive pregnant women. Variations were evaluated by polymerase chain reaction-restriction fragment length polymorphism. NO and ACE levels were determined using ELISA. There was no difference in the distribution of individual NOS3 and ACE polymorphisms in the study groups. Haplotype analysis showed a global difference in the NOS3 haplotype distribution between the PE and non-PE subjects (P=0.03). The presence of AGT 704C allele was associated with a reduced risk of developing PE (odds ratio: 0.33, 95% CI: 0.19-0.59 in recessive mode). Circulating total NO and ACE levels were similar in three groups. No relationship was found between circulating NO levels and any of the NOS3 polymorphisms, but the circulating ACE levels were higher in those with DD genotype (P<0.05). In conclusion, there was no association between individual NOS3 and the ACE gene polymorphisms and hypertensive disorders of pregnancy in north Indian women. The presence of minor alleles at all the three sites in NOS3 seemed to increase the risk of PE, and AGT 704C allele was associated with a reduced PE risk. The complexity of interaction between these genetic abnormalities requires further studies.

Vascular endothelial growth factor gene polymorphisms and pregnancy

Vascular endothelial growth factor (VEGF) is a major angiogenic factor and prime regulator of endothelial cell proliferation. During pregnancy, VEGF is essential for the proliferation of trophoblasts, the development of embryonic vasculature and the growth of maternal and fetal blood cells in utero. In cases of pre-eclampsia and in some circumstances of preterm labor-raised umbilical cord serum, VEGF levels might be correlated with the clinical development of the above pathological disorders. Genetic alteration as 936C/T VEGF gene polymorphism has a statistical significant correlation with the severity of pre-eclampsia. The same VEGF gene polymorphism, which has been associated with lower protein production, has an increased risk of spontaneous preterm delivery in a Greek-studied population. Homozygotes were found to carry the greatest risk with a lesser proportionate risk associated with heterozygosity, whereas women with the -1154 allele of the VEGF gene have an increased risk of recurrent pregnancy loss. In this review, we present evidence that demonstrates an implication of VEGF gene polymorphisms in the pathological disorders of pregnancy. However, further genetic studies are needed to confirm these data.

ADMA and the role of the genes: lessons from genetically modified animals and human gene polymorphisms

In large population-based cohorts, elevated plasma levels of asymmetric dimethylarginine (ADMA) were found to be associated with cardiovascular events and mortality. Impairment of nitric oxide (NO) synthesis from l-arginine has been postulated as underlying mechanism. In the present review, we compare different experimental models of NOS deficiency or overexpression with corresponding models of altered metabolism of ADMA by dimethylarginine dimethylaminohydrolase (DDAH). The latter models show a considerable overlap with the pathophysiological features of impaired NO synthesis, such as impaired endothelial function, elevation of blood pressure, and microvascular fibrosis. In line with these findings, first data regarding genetic variation of DDAH-metabolism in humans are reminiscent of the (rather modest) effects previously observed with polymorphisms of the eNOS gene. However, several peculiar observations suggest that ADMA- or DDAH-related pathology may extend beyond impairment of NO-mediated signalling. Notably, the complete knock out of DDAH1 appears to be lethal while triple NOS(-/-) mice are viable. Moreover, some ADMA-mediated pathology appears to respond rather to ACE-inhibition than to l-arginine. Here, a further investigation of alternative target enzymes for ADMA and other endogenous DDAH substrates is warranted.Taken together, the current data suggest that ADMA-related pathology can largely but not completely be explained by impaired NO metabolism.