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

Factors associated with preeclampsia and the hypertensive disorders of pregnancy amongst Indigenous women of Canada, Australia, New Zealand, and the United States: A systematic review and meta-analysis

PURPOSE OF THE REVIEW

Preeclampsia and the Hypertensive Disorders of Pregnancy (HDP) occur more frequently amongst Indigenous women and can have short- and long-term impacts on maternal and infant health and wellbeing. To understand factors associated with increased risk for Indigenous women a systematic review and meta-analysis was conducted. The PRISMA guidelines were adhered to, and the review protocol was registered on PROSPERO (Registration CRD42023381847). EndNote, Covidence and Excel were used to screen and extract data, with studies assessed using JBI critical appraisal tools.

RECENT FINDINGS

Seven studies from Canada, Australia, and the United States (none from New Zealand) were included in this review. Meta-analysis showed women classified as overweight (OR 1.32, 95% CI: 1.09-1.60), obese (OR 1.88, 95% CI: 1.57-2.25), or having high mean BMI (MD 3.02 95% CI: 1.72-4.31), high mean systolic blood pressure (MD 15.19 95% CI: 12.83-17.541), or high mean diastolic blood pressure (MD 15.26 95% CI: 13.05-17.47), pre-pregnancy diabetes (OR 3.63, 95% CI: 1.66-17.94), or high microalbuminuria (OR 2.76, 95% CI: 1.40-5.43) were more likely to be diagnosed with preeclampsia. Smoking (OR 0.77, 95% CI: 0.58-1.03), alcohol consumption (OR 1.70, 95% CI: 0.76-3.81), and gestational diabetes (OR 1.74, 95% CI: 0.90-3.37) were not associated with preeclampsia. Understanding factors associated with increased preeclampsia/HDP risk amongst Indigenous women is important to minimising adverse perinatal events and future health complications. This review demonstrates current gaps in the evidence, specifically in relation to social, economic, and environmental factors.

Individual- and community-level risk factors for maternal morbidity and mortality among Native American women in the USA: a systematic review

INTRODUCTION AND OBJECTIVE

Maternal morbidity and mortality (MMM) is a public health concern in the USA, with Native American women experiencing higher rates than non-Hispanic White women. Research on risk factors for MMM among Native American women is limited. This systematic review comprehensively synthesizes and critically appraises the literature on risk factors for MMM experienced by Native American women.

METHODS AND ANALYSIS

A systematic search was conducted on 10 October 2022 in PubMed, Embase, CINAHL and Scopus for articles published since 2012. Selection criteria included observational studies set in the USA, involving Native American women in the perinatal period, and examining the relationship between risk factors and MMM outcomes. Three reviewers screened and extracted data from the included studies, with risk of bias assessed using the National Institutes of Health Quality Assessment Tools. Data were analysed descriptively.

RESULTS

15 studies were included. All studies used administrative databases, with settings, including nationwide (seven studies), statewide (four studies) and Indian reservations (four studies). The majority of studies focused on hypertensive disorders of pregnancy (eight studies) and severe maternal morbidity (SMM) (four studies). 26 risk factors were identified. Key risk factors included Native American race (six studies), rural maternal residency (four studies), overweight/obese body mass index (two studies), maternal age (two studies), nulliparity (two studies) and pre-existing medical conditions (one study).

CONCLUSION

This review identified risk factors associated with MMM among Native American women, including rural residency, overweight or obesity and advanced maternal age. However, the findings also reveal a scarcity of research specific to this population, limiting the ability to fully understand these risk factors and develop effective interventions. These results emphasise the need for further research and culturally relevant studies to inform public health and address disparities for Native American women, particularly those in rural areas.

PROSPERO REGISTRATION NUMBER

CRD42022363405.

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.

Association Study of Single Nucleotide Polymorphisms of Endoplasmic Reticulum Aminopeptidase 1 and 2 Genes in Iranian Women with Preeclampsia

BACKGROUND

Endoplasmic reticulum aminopeptidases 1 and 2 (ERAP1 and 2) are involved in blood pressure regulation and single nucleotide polymorphisms (SNPs) of these genes have been linked to preeclampsia. This study intended to assess the association of ERAP1 and 2 genes polymorphism with Iranian preeclamptic women.

METHODS

In this case-control study, 148 preeclamptic and 133 pregnant women were selected from the Kosar Hospital, Qazvin, Iran, during 2013-2015. In order to genotype the subjects for rs28096, rs30187, rs26653, rs3734016, rs34750 and rs2549782, rs17408150 for ERAP1 and 2 genes, respectively, Real-Time PCR allelic discrimination approach was exploited.

RESULTS

Neither allelic nor genotype frequencies of all seven polymorphisms were significantly different between two groups. Though, ACGACTT and GTCAGGA haplotypes were related with decreased (P=0.0079, OR=0.559, 95% CI: 0.363-0.861 and P=0.02, OR=0.417, 95% CI: 0.194-0.896, respectively), but ACGACGT and GTGACTT haplotypes were associated with an increased (P=0.00082, OR=3.657, 95% CI: 1.630-8.206 and P=0.02, OR=2.401, 95% CI: 1.119-5.151, respectively) risk of preeclampsia. Moreover, some positions were detected to be in linkage disequilibrium.

CONCLUSION

Ongoing investigation resulted differently from before performed studies considering the role of ERAP1 and ERAP2 gene polymorphisms in predisposing women to preeclampsia, emphasizing on the genetic structure differences among various racial populations.

Pre-eclampsia in American Indians/Alaska Natives and Whites: The Significance of Body Mass Index

Introduction The prevalence of pre-eclampsia, a major cause of maternal morbidity, varies by race, being greater in African Americans, and lower in Asians and Hispanics than in White women. Little is known about its prevalence in American Indians/Alaska Natives (AI/ANs). We estimated pre-eclampsia risk in AI/ANs compared to Whites, with consideration of the potential effect of obesity, a major risk factor for pre-eclampsia, and a condition disproportionately affecting AI/AN women. Methods This retrospective cohort study of linked birth-hospital discharge data from Washington State (2003-2013) included all AI/AN women and a sample of White first-time mothers with singleton deliveries. Logistic regression was used to estimate odds ratio (OR) and 95 % confidence intervals (CI) for pre-eclampsia risk in AI/ANs compared to Whites, first controlling for several important risk factors, and subsequently with additional adjustment for pre-pregnancy body mass index (BMI). Results AI/ANs had an increased risk of pre-eclampsia compared to Whites after controlling for all covariates except BMI (OR 1.17, 95 % CI 1.06-1.29). After further adjustment for BMI, the racial disparity in pre-eclampsia risk was greatly attenuated (OR 1.05, 95 % CI 0.95-1.16). Discussion This population-based study suggests that any increased risk in AI/ANs relative to Whites may be at least partly due to differences in BMI.

Preeclampsia/Eclampsia candidate genes show altered methylation in maternal leukocytes of preeclamptic women at the time of delivery

OBJECTIVE

To analyze methylation profiles of known preeclampsia/eclampsia (PE) candidate genes in normal (NL) and preeclamptic (PE) women at delivery.

METHODS

A matched case-control study comparing methylation in 79 CpG sites/33 genes from an independent gene set in maternal leukocyte DNA in PE and NL (n = 14 each) on an Illumina BeadChip platform. Replication performed on second cohort (PE = 12; NL = 32).

RESULTS

PE demonstrates differential methylation in POMC, AGT, CALCA, and DDAH1 compared with NL.

CONCLUSION

Differential methylation in four genes associated with PE may represent a potential biomarker or an epigenetic pathophysiologic mechanism altering gene transcription.

Differences in the association between maternal serum homocysteine and ADMA levels in women with pregnancies complicated by preeclampsia and/or intrauterine growth restriction

OBJECTIVE

The aim of our study was to investigate the association between homocysteine and asymmetric dimethylarginine in preeclamptic women with and without intrauterine growth restriction compared with normal healthy uncomplicated pregnancies and normotensive pregnancies complicated by idiopathic isolated intrauterine fetal growth restriction.

METHODS

The maternal serum homocysteine and asymmetric dimethylarginine concentrations were determined using a sandwich enzyme-linked immunosorbent assays.

RESULTS

A statistically significant positive correlation of maternal serum homocysteine levels with the serum asymmetric dimethylarginine levels was observed in healthy normotensive uncomplicated pregnant women from the control group and in preeclamptic patients with appropriate-for-gestational-age fetuses (R = 0.380079, p-value = 0.002311* and R = 0.455797, p-value = 0.004030* for the control and the P groups, respectively). However, this correlation was not significant in women with pregnancy complicated by intrauterine growth restriction, both isolated and in the course of severe preeclampsia.

CONCLUSION

These findings provide support for the hypothesis that elevated levels of asymmetric dimethylarginine in pregnancy complicated by preeclampsia are associated with elevated homocysteine levels. But our results also demonstrate that in pregnancies complicated by intrauterine growth restriction, this mechanism is important, although not the only one.

Genetic variants, immune function, and risk of pre-eclampsia among American Indians

PROBLEM

To determine the prevalence in an American Indian population of genetic variants with putative effects on immune function and determine if they are associated with pre-eclampsia (PE).

METHOD OF STUDY

In a study of 66 cases and 130 matched controls, six single nucleotide polymorphisms (SNP) with either previously demonstrated or postulated modulating effects on the immune system were genotyped. Allele frequencies and various genetic models were evaluated by conditional logistic regression in both univariate and multiply adjusted models.

RESULTS

Although most genetic variants lacked evidence of association with PE, the minor allele of the CRP related, rs1205 SNP in a dominant model with adjustment for age at delivery, nulliparity, and body mass index, exhibited an odds ratio of 0.259 (95% CI of 0.08-0.81, P=0.020) in relation to severe PE (48 cases). The allelic prevalence of this variant was 46.1% in this population.

CONCLUSION

Of the six SNPs related to immune function in this study, a functional variant in the 3'UTR of the CRP gene was shown to be associated with severe PE in an American Indian population.