The Norwegian preeclampsia family cohort study: a new resource for investigating genetic aspects and heritability of preeclampsia and related phenotypes

No association of a Vascular endothelial growth factor A (VEGFA) gene polymorphism with pre-eclampsia among pregnant women in Uganda

BACKGROUND

Vascular endothelial growth factor A (VEGFA) is a major angiogenic factor that plays an important role in the formation of blood vessels during embryonic development. VEGFA has been implicated in the pathophysiology of pre-eclampsia (PE), since pre-eclamptic women present with reduced levels of free circulating VEGFA. The 3' untranslated region (3'-UTR) of the VEGFA gene consists of elements that regulate the transcription and hence expression of the VEGFA protein in circulation. Hence it is suggested that variations thereof could underlie the reduced VEGFA levels observed in pre-eclamptic women. The purpose of this study was to investigate presence of the + 936C/T polymorphism, a common single nucleotide polymorphism (SNP) in the 3'-UTR of the VEGFA gene, and determine its association with PE among pregnant women in Uganda.

RESULTS

There was no significant difference observed in the allele and genotype frequencies of the + 936C/T 3' UTR-VEGFA polymorphism between pre-eclamptic and normotensive pregnant women (P > 0.05). Additionally, there was no significant difference in the median plasma levels of free VEGFA among women with the wild type, CT and TT genotypes of the + 936C/T VEGFA polymorphism (median = 0.84 pg/mL (IQR = 0.39-1.41) Vs 1.05 (0.61-1.18) Vs 1.05 (1.05-1.05) respectively, p-value = 0.7161).

CONCLUSIONS

These study findings indicate that the + 936C/T 3' UTR-VEGFA polymorphism had no significant association with increased susceptibility to PE among women in Uganda. Further studies with a larger sample size are recommended.

Evaluation of epigenetic age calculators between preeclampsia and normotensive pregnancies in an Australian cohort

Advanced biological aging, as assessed through DNA methylation markers, is associated with several complex diseases. The associations between maternal DNA methylation age and preeclampsia (PE) have not been fully assessed. The aim of this study was to examine if increased maternal DNA methylation age (DNAmAge) was shown to be accelerated in women with PE when compared to women who had normotensive pregnancies. The case/control cohort available for study consisted of 166 women (89 with normotensive pregnancy, 77 with PE) recruited previously at the Royal Women’s Hospital in Melbourne, Australia. DNA methylation profiles were obtained using the Illumina EPIC Infinium array for analysis of genomic DNA isolated from whole blood. These profiles were used to calculate seven estimates of DNAmAge and included (1) Horvath, (2) Hannum, (3) Horvath Skin and Blood, (4) Wu, (5) PhenoAge, (6) telomere length and (7) GrimAge and its surrogate measures. Three measures of DNA methylation age acceleration were calculated for all seven measures using linear regression. Pearson's correlation was performed to investigate associations between chronological age and DNAmAge. Differences between chronological age and DNAmAge and epigenetic age acceleration were investigated using t-tests. No significant difference was observed for chronological age between women with PE (age = 30.53 ± 5.68) and women who had normotensive pregnancies (age = 31.76 ± 4.76). All seven DNAmAge measures were significantly correlated (p < 0.001) with chronological age. After accounting for multiple testing and investigating differences in DNAmAge between normotensive women and women with PE, only Wu DNAmAge was significant (p = 0.001). When examining differences for epigenetic age acceleration between PE and normotensive women Hannum, Wu, and PhenoAge DNAmAge estimates (p < 0.001) were significant for both epigenetic age acceleration and intrinsic acceleration models. We found that accelerated maternal DNAmAge is increased in women with PE in some models of epigenetic aging. This research underlines the importance for further investigation into the potential changes of differential DNA methylation in PE.

Susceptibility to preeclampsia is associated with a 50-bp insertion/deletion polymorphism at the promoter region of the SOD1 gene

Objective

There is much evidence that oxidative stress is involved in the pathogenesis of preeclampsia (PE). A 50 bp insertion/deletion (Ins/Del) functional polymorphism in the promoter region of SOD1 has been reported. Due to a total lack of data, the aim of this study was to investigate the association between the SOD1 (Ins/Del) polymorphism and the risk of PE.

Material and Methods

The current hospital-based case-control study included a total of 172 preeclamptic and 171 non-preeclamptic pregnancies. Genotyping was performed using the polymerase chain reaction method.

Results

Statistical analysis revealed that the Del/Del genotype significantly correlated with susceptibility to PE [odds ratio (OR): 6.53, 95% confidence interval (CI): 1.43-29.7, p=0.015]. Since maternal body mass index, family history of PE in first degree relatives, and educational levels were statistically associated with the susceptibility to PE, further analyses were carried out in order to estimate the adjusted ORs. After adjustment for aforementioned variables, the Del/Del genotype increased the risk of PE (OR: 5.98, 95% CI: 1.21-29.5, p=0.028).

Conclusion

The 50 bp Ins/Del in promoter region of the SOD1 gene could be an intriguing susceptibility factor for developing preeclampsia in Iranian Caucasians.

Novel associations of SNPs MYLIP rs3757354 and ABCA1 2230806 gene with early-onset-preeclampsia: A case-control candidate genetic study

OBJECTIVE

To investigate the association between MYLIP rs3757354 and ABCA1 2230806 single nucleotide polymorphisms in women with preeclampsia in China.

STUDY DESIGN

The case-control study involved 205 patients with preeclampsia and 145 controls. All women with preeclampsia were divided into two groups: 78 patients with early-onset preeclampsia and 127 with late-onset preeclampsia.

MAIN OUTCOME MEASURE

MYLIP rs3757354 and ABCA1 rs2230806 SNPs were analyzed through multiplex PCR for targeted next-generation sequencing technology. A secondary outcome was lipid profile changes and liver function in women with PE.

RESULTS

Maternal age (OR: 1.073, 95% CI = 1.006-1.145), BMI (OR: 1.118, 95% CI = 1.040-1.201), TG/HDL-C (OR: 1.536, 95% CI = 1.080-2.183), and TT genotype of SNP rs3757354 (OR: 3.238, 95% CI = 1.313-7.990) were associated with EOPE risk. Our study found that patients with TT genotype of ABCA1 rs2230806 had more severe hepatic dysfunction and higher HDL levels in the EOPE group compared with CC/CT genotype. There was no association between rs2230806 and the risk of PE.

CONCLUSION

The polymorphisms of rs3757354 are associated with the risk of EOPE in Chinese pregnant women. The TT genotype in ABCA1 rs2230806 is a strong predictive risk for elevated aminotransferase levels in pregnant women with EOPE.

A risk factor-based predictive model for new-onset hypertension during pregnancy in Chinese Han women

BACKGROUND

Hypertensive disorders of pregnancy (HDP) is one of the leading causes of maternal and neonatal mortality, increasing the long-term incidence of cardiovascular diseases. Preeclampsia and gestational hypertension are the major components of HDP. The aim of our study is to establish a prediction model for pregnant women with new-onset hypertension during pregnancy (increased blood pressure after gestational age > 20 weeks), thus to guide the clinical prediction and treatment of de novo hypertension.

METHODS

A total of 117 pregnant women with de novo hypertension who were admitted to our hospital's obstetrics department were selected as the case group and 199 healthy pregnant women were selected as the control group from January 2017 to June 2018. Maternal clinical parameters such as age, family history and the biomarkers such as homocysteine, cystatin C, uric acid, total bile acid and glomerular filtration rate were collected at a mean gestational age in 16 to 20 weeks. The prediction model was established by logistic regression.

RESULTS

Eleven indicators have statistically significant difference between two groups (P < 0.05). These 11 factors were substituted into the logistic regression equation and 7 independent predictors were obtained. The equation expressed including 7 factors. The calculated area under the curve was 0.884(95% confidence interval: 0.848-0.921), the sensitivity and specificity were 88.0 and 75.0%. A scoring system was established to classify pregnant women with scores ≤15.5 as low-risk pregnancy group and those with scores > 15.5 as high-risk pregnancy group.

CONCLUSIONS

Our regression equation provides a feasible and reliable means of predicting de novo hypertension after pregnancy. Risk stratification of new-onset hypertension was performed to early treatment interventions in high-risk populations.

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.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.