Maternal hypertensive traits and adverse outcome in pregnancy: a Mendelian randomization study.

INTRODUCTION: Hypertensive disorders of pregnancy are associated with adverse feto-maternal outcomes. Existing evidence is mostly limited to observational studies, which are liable to confounding and bias. This study investigated the causal relevance of component hypertensive indices on multiple adverse pregnancy outcomes using Mendelian randomization. METHODS: Uncorrelated ( r2  < 0.001) genome-wide significant ( P  < 5 × 10 -8 ) single-nucleotide polymorphisms associated with SBP, DBP and pulse pressure (PP) were selected as instrumental variables. Genetic association estimates for outcomes of preeclampsia or eclampsia, preterm birth, placental abruption and hemorrhage in early pregnancy were extracted from summary statistics of genome-wide association studies in the FinnGen cohort. Two-sample, inverse-variance weighted Mendelian randomization formed the primary analysis method. Odds ratios (OR) are presented per-10 mmHg higher genetically predicted hypertensive index. RESULTS: Higher genetically predicted SBP were associated with higher odds of preeclampsia or eclampsia [OR 1.81, 95% confidence interval (CI) 1.68-1.96, P  = 5.45 × 10 -49 ], preterm birth (OR 1.09, 95% CI 1.03-1.16, P  = 0.005) and placental abruption (OR 1.33, 95% CI 1.05-1.68, P  = 0.016). Higher genetically-predicted DBP was associated with preeclampsia or eclampsia (OR 2.54, 95% CI 2.21-2.92, P  = 5.35 × 10 -40 ). Higher genetically predicted PP was associated with preeclampsia or eclampsia (OR 1.68, 95% CI 1.47-1.92, P  = 1.9 × 10 -14 ) and preterm birth (OR 1.18, 95% CI 1.06-1.30, P  = 0.002). CONCLUSION: This study provides genetic evidence to support causal associations of SBP, DBP and PP on multiple adverse outcomes of pregnancy. SBP and PP were associated with the broadest range of adverse outcomes, suggesting that optimized management of blood pressure, particularly SBP, is a key priority to improve feto-maternal health.

Safety of beta-blocker and calcium channel blocker antihypertensive drugs in pregnancy: a Mendelian randomization study.

BACKGROUND: Beta-blocker (BB) and calcium channel blocker (CCB) antihypertensive drugs are commonly used in pregnancy. However, data on their relative impact on maternal and foetal outcomes are limited. We leveraged genetic variants mimicking BB and CCB antihypertensive drugs to investigate their effects on risk of pre-eclampsia, gestational diabetes and birthweight using the Mendelian randomization paradigm. METHODS: Genetic association estimates for systolic blood pressure (SBP) were extracted from summary data of a genome-wide association study (GWAS) on 757,601 participants. Uncorrelated single-nucleotide polymorphisms (SNPs) associated with SBP (p < 5 × 10-8) in BB and CCB drug target gene regions were selected as proxies for drug target perturbation. Genetic association estimates for the outcomes were extracted from GWASs on 4743 cases and 136,325 controls (women without a hypertensive disorder in pregnancy) for pre-eclampsia or eclampsia, 7676 cases and 130,424 controls (women without any pregnancy-related morbidity) for gestational diabetes, and 155,202 women (who have given birth at least once) for birthweight of the first child. All studies were in European ancestry populations. Mendelian randomization estimates were generated using the two-sample inverse-variance weighted model. RESULTS: Although not reaching the conventional threshold for statistical significance, genetically-proxied BB was associated with reduced risk of pre-eclampsia (OR per 10 mmHg SBP reduction 0.27, 95%CI 0.06-1.19, p = 0.08) and increased risk of gestational diabetes (OR per 10 mmHg SBP reduction 2.01, 95%CI 0.91-4.42, p = 0.08), and significantly associated with lower birthweight of first child (beta per 10 mmHg SBP reduction - 0.27, 95%CI - 0.39 to - 0.15, p = 1.90 × 10-5). Genetically-proxied CCB was associated with reduced risk of pre-eclampsia and eclampsia (OR 0.62, 95%CI 0.43-0.89, p = 9.33 × 10-3), and was not associated with gestational diabetes (OR 1.05, 95% CI 0.76-1.45, p = 0.76) or changes in birthweight of first child (beta per 10 mmHg SBP reduction 0.02, 95%CI - 0.04-0.07, p = 0.54). CONCLUSIONS: While BB and CCB antihypertensive drugs may both be efficacious for lowering blood pressure in pregnancy, this genetic evidence suggests that BB use may lower birthweight. Conversely, CCB use may reduce risk of pre-eclampsia and eclampsia without impacting gestational diabetes risk or birthweight. These data support further study on the effects of BBs on birthweight.

ATP2B1 gene rs71454161, rs73196661 and rs73196675 polymorphisms in eclampsia.

OBJECTIVE: We aimed to explore the associations of the ATP2B1 gene polymorphisms with eclampsia. PATIENTS AND METHODS: A total of 150 patients with eclampsia (disease group) and 150 healthy pregnant women (control group) were taken as the subjects of study. The peripheral blood of the two groups of subjects was collected to extract deoxyribonucleic acids (DNAs), and the ATP2B1 gene rs71454161, rs73196661 and rs73196675 polymorphisms were detected by sequencing the Polymerase Chain Reaction (PCR) products, and then, analyzed combined with gene expression determined via Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR) and clinical indicators, such as 24-h urine protein, platelets, and LDH. RESULTS: A difference was observed in the allele distribution of ATP2B1 gene rs71454161 (p=0.000) and rs73196661 (p=0.011) between the disease group and control group. Disease group exhibited higher frequencies of allele G of rs71454161 and allele T of rs73196661 than control group. Besides, there was a difference in the genotype distribution of ATP2B1 gene rs71454161 (p=0.000), rs73196661 (p=0.000) and rs73196675 (p=0.000) between disease group and control group. Disease group exhibited higher frequencies of genotype GG of rs71454161, genotype TT of rs73196661 and genotype CG of rs73196675 than control group. Moreover, a difference in the distributions of ATP2B1 gene rs71454161 (p=0.000) and rs73196661 (p=0.014) was found between the two groups in the dominant model. Disease group exhibited lower frequencies of AA+AG of rs71454161 and CC+CT of rs73196661 than control group in the dominant model. Differences in the distributions of haplotypes ACC (p=0.000), ATC (p=0.047) and GTC (p=0.000) of ATP2B1 gene rs71454161, rs73196661 and rs73196675 were observed between disease group and control group. Furthermore, a high degree of linkage disequilibrium was detected between rs71454161 and rs73196661 (D'=0.329). The ATP2B1 gene rs73196675 polymorphism was evidently correlated with the gene expression of ATP2B1 (p<0.05), and the patients with genotype GG had a lower expression level of ATP2B1. The ATP2B1 gene rs71454161 was evidently correlated with the 24-h urinary protein in eclampsia patients (p=0.021), and the patients with genotype AG had a higher level of 24-h urinary proteins. The rs73196661 polymorphism was significantly correlated with LDH (p=0.000), and the patients with genotype CC had a higher level of LDH. CONCLUSIONS: The ATP2B1 gene polymorphism was significantly correlated with the occurrence and progression of eclampsia.

Genetic association of ERAP1 and ERAP2 with eclampsia and preeclampsia in northeastern Brazilian women.

The clinical spectrum of hypertensive disorders of pregnancy (HDP) is determined by the interplay between environmental and genetic factors, most of which remains unknown. ERAP1, ERAP2 and LNPEP genes code for multifunctional aminopeptidases involved with antigen processing and degradation of small peptides such as angiotensin II (Ang II), vasopressin and oxytocin. We aimed to test for associations between genetic variants in aminopeptidases and HDP. A total of 1282 pregnant women (normotensive controls, n = 693; preeclampsia, n = 342; chronic hypertension with superimposed preeclampsia, n = 61; eclampsia, n = 74; and HELLP syndrome, n = 112) were genotyped for variants in LNPEP (rs27300, rs38034, rs2303138), ERAP1 (rs27044, rs30187) and ERAP2 (rs2549796 rs2927609 rs11135484). We also evaluated the effect of ERAP1 rs30187 on plasma Ang II levels in an additional cohort of 65 pregnant women. The genotype C/C, in ERAP1 rs30187 variant (c.1583 T > C, p.Lys528Arg), was associated with increased risk of eclampsia (OR = 1.85, p = 0.019) whereas ERAP2 haplotype rs2549796(C)-rs2927609(C)-rs11135484(G) was associated with preeclampsia (OR = 1.96, corrected p-value = 0.01). Ang II plasma levels did not differ across rs30187 genotypic groups (p = 0.895). In conclusion, ERAP1 gene is associated with eclampsia whereas ERAP2 is associated with preeclampsia, although the mechanism by which genetic variants in ERAPs influence the risk of preeclampsia and eclampsia remain to be elucidated.

Predictive value of 4-Hydroxyglutamate and miR-149-5p on eclampsia.

This research aimed at exploring the predictive value of 4-Hydroxyglutamate and miR-149-5p on eclampsia. Preeclampsia patients admitted to our hospital (n = 204), with 112 mild patients and 92 severe patients. Thereinto, pregnant women who underwent physical examination were regarded as a normal group (NG) (n = 100). Serum 4-Hydroxyglutamate levels and miR-149-5p in each group were detected. The serum 4-Hydroxyglutamate level in pregnant women in the NG was markedly lower than that in preeclampsia, while the miR-149-5p level was higher (p = 0.001). The serum 4-Hydroxyglutamate level in severe preeclampsia was higher than that in mild preeclampsia, while the miR-149-5p level was lower (p = 0.001). Partial thromboplastin time (APTT) and prothrombin time (PT) of preeclampsia patients were lower than those of the NG, while Fibrinogen (Fib) was higher (p = 0.001). With the aggravation of the condition of patients, PT, APTT decreased and Fib index increased. In preeclampsia patients, serum 4-Hydroxyglutamate was negatively correlated with PT and APTT, positively correlated with Fib content (p < 0.001); serum miR-149-5p was dramatically positively correlated with PT and APTT, negatively correlated with Fib content (p < 0.001). 4-Hydroxyglutamate and miR-149-5p were relevant to the occurrence time of preeclampsia; 4-Hydroxyglutamate, miR-149-5p and their combination could be used for preeclampsia diagnosis. According to the situation of newborn, they were divided into good and poor groups. The 4-Hydroxyglutamate level in the good group was lower than that in the poor group, while the miR-149-5p level was higher. The adverse prognosis of preeclampsia patients was predicted by 4-Hydroxyglutamate and miR-149-5p. 4-Hydroxyglutamate is highly expressed in preeclampsia, while miR-149-5p is low. Single and combined detection of 4-Hydroxyglutamate, miR-149-5p can be used for preeclampsia diagnosis and prediction.

Quantitative Alterations in Complement Alternative Pathway and Related Genetic Analysis in Severe Phenotype Preeclampsia.

Background: Preeclampsia and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome share many clinical and biologic features with thrombotic microangiopathy syndromes caused by complement abnormalities. Our hypothesis was that similar functional and genetic alterations in the complement alternative pathway (CAP) are present in these disorders of pregnancy. Methods: We conducted quantitative analysis of proteins involved in CAP using ELISA and nephelometry on prospectively collected blood samples from patients with severe phenotype preeclampsia (defined as delivery ≤34 weeks due to preeclampsia), HELLP syndrome, or eclampsia, and matched normotensive controls (n=25 in each arm) between 2011 and 2016. Sequencing was performed to interrogate 14 genes encoding CAP components. Results: Both groups were similar in age, gravidity, parity, marital status, and race. The study group had a higher BMI (mean±SD, 32±8 versus 25±4 kg/m2; P=0.002) and earlier gestational age at delivery (32.5±3.6 versus 40.3±1 weeks; P<0.001). Serologic studies demonstrated elevated Bb subunit (median [range], 1.2 [0.5-4.3] versus 0.6 [0.5-1] µg/ml; P<0.001), complement C5 concentration (28 [18-33] versus 24 [15-34] mg/dl; P=0.03), and sMAC (371 [167-761] versus 184 [112-249] ng/ml; P<0.001) concentrations in patients with preeclampsia. Two thirds of patients with preeclampsia had at least one nonsynonymous sequence variant in CAP genes. Conclusion: Patients with severe phenotype preeclampsia manifest functional alterations in CAP activation. Genetic variants in the CAP genes were detected in several patients, but a larger population study is necessary to fully evaluate genetic risk. Genetic screening and complement-targeted treatment may be useful in risk stratification and novel therapeutic approaches.

Relationship between onset of eclampsia and AGTR1 gene polymorphisms.

OBJECTIVE: We aimed to study the correlations of angiotensin II receptor type 1 (AGTR1) gene polymorphisms with the occurrence and development of eclampsia. PATIENTS AND METHODS: A total of 200 pregnant women with eclampsia admitted to our hospital from January 1, 2017 to September 30, 2019 were collected as observation group and 200 normal pregnant women during the same period were recruited in the control group. Genome sequencing was performed to detect the AGTR1 gene polymorphisms in the two groups. Expression level of AGTR1 in both groups was detected. The influences of AGTR1 on clinical data of pregnant women with eclampsia were analyzed. RESULTS: There were no significant differences in age (p=0.545), height (p=0.738), weight (p=0.695) and hypertension (p=0.372) between observation group and control group. However, significant differences were found in the distributions of alleles at AGTR1 rs1799870 (p=0.002) and AGTR1 rs52936049 (p=0.047) between groups. The frequencies of T allele at rs1799870 and rs52936044 in observation group were higher than those in the control group. In addition, the distributions of AGTR1 gene genotypes at rs1799870 (p=0.012), rs144520513 (p=0.008) and rs529360494 (p p =0.036) in observation group differed from those in control group. Observation group had higher frequencies of TT genotype at rs1799870, GG genotype at rs144520513 and TG genotype at rs529360494 than those in control group. Besides, the frequency of CGG haplotype (p=0.008) of AGTR1 gene in observation group was notably lower than that in the control group, while the frequency of TGT haplotype (p=0.012) of AGTR1 gene in the former was remarkably higher than that in the latter. Moreover, the linkage disequilibrium between rs529360494 and rs144520513 of AGTR1 gene was relatively high (D'=0.623). AGTR1 gene polymorphism rs529360494 showed an evident relationship with the expression of AGTR1 gene, and the expression of AGTR1 in pregnant women with eclampsia who carried TG genotype was markedly reduced (p<0.05). Furthermore, AGTR1 gene polymorphism rs1799870 was associated with prothrombin time (PT) in pregnant women with eclampsia (p=0.046), and PT in those carrying genotype TC was shorter. Rs144520513 was related to the levels of triglyceride (TG) (p<0.001) and low-density lipoprotein (LDL) (p<0.001) in pregnant women with eclampsia, and TG and LDL levels were significantly lower. CONCLUSIONS: AGTR1 gene polymorphisms are closely associated with the onset and progression of eclampsia.

Correlations of CYP11B2 gene polymorphisms with eclampsia.

OBJECTIVE: The aim of this study was to explore the relationship between CYP11B2 gene polymorphisms and eclampsia. PATIENTS AND METHODS: A total of 400 pregnant women treated in our hospital were enrolled in this study, including 200 normal pregnant women (pregnancy group) and 200 pregnant women with eclampsia (eclampsia group). Peripheral blood was collected from subjects of the two groups. Subsequently, genomic deoxyribonucleic acids (DNAs) were extracted and amplified via polymerase chain reaction (PCR) for detection of CYP11B2 rs4543, rs3802228 and rs104894072 polymorphisms. The expression level of CYP11B2 gene was measured as well. Additionally, the correlations of CYP11B2 gene polymorphisms with blood pressure and coagulation and renal function indexes were analyzed. RESULTS: The distribution of alleles of rs4543 locus in CYP11B2 gene was significantly different between eclampsia group and pregnancy group (p=0.027). The frequency of the allele C was significantly lower in eclampsia group than that of pregnancy group (p<0.05). There was a statistically significant difference in the genotype distribution of CYP11B2 rs3802228 (p=0.000) and rs104894072 (p=0.000) between eclampsia group and pregnancy group (p<0.05). Meanwhile, the frequency of AA genotype of rs3802228 and TG genotype of rs104894072 was remarkably higher in eclampsia group than that in pregnancy group (p<0.05). The distribution of the locus rs104894072 (p=0.044) in dominant model and rs3802228 (p=0.002) in recessive model in eclampsia group was different from that in pregnancy group (p<0.05). Eclampsia group showed remarkably elevated frequency of TT + TG of the locus rs104894072 in dominant model and lowered frequency of AG + GG of the locus rs3802228 in recessive model (p<0.05). Similarly, a significant difference was observed in the distribution of the haplotypes CGG (p=0.001) and TGT (p=0.048) in CYP11B2 gene between eclampsia group and pregnancy group (p<0.05). The linkage disequilibrium of the loci rs3802228 and rs104894072 was relatively high (D'=0.382). The polymorphism of the locus rs104894072 in CYP11B2 gene had an evident relation to CYP11B2 gene expression (p<0.05). Meanwhile, the expression of CYP11B2 gene was markedly higher in patients with GG genotype in eclampsia group (p<0.05). The polymorphism of CYP11B2 rs4543 was notably associated with PT level of patients in eclampsia group (p=0.000). Conversely, rs3802228 polymorphism was correlated with 24 h urine protein level (p=0.000). Besides, the proportion of patients with CGG haplotype was significantly larger among patients with systolic blood pressure of 140-160 mmHg (p<0.05). In addition, the proportion of patients with TGT haplotype was evidently greater among patients with systolic blood pressure >180 mmHg in eclampsia group (p<0.05). CONCLUSIONS: CYP11B2 gene polymorphisms are significantly correlated with the development and progression of eclampsia.

Association of ATP2B1 gene polymorphism with incidence of eclampsia.

OBJECTIVE: The aim of this study was to analyze the association of ATPase plasma membrane Ca2+ transporting 1 (ATP2B1) gene polymorphism with the incidence of eclampsia, and to investigate the possible underlying mechanism. PATIENTS AND METHODS: ATP2B1 genotype and allele distributions in umbilical venous blood cells were analyzed in 50 control subjects and 117 eclampsia patients via Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and TaqMan genotyping technique. Meanwhile, the differences in the single nucleotide polymorphisms at rs2681472 and rs17249754 in the case group and control group were analyzed using the χ2-test. The risk factors for eclampsia were analyzed via univariate, multivariate, and Logistic regression analyses. Furthermore, the associations of rs2681472 gene polymorphism with risk factors for eclampsia (hypertension and lower extremity edema) were verified via χ2-test. RESULTS: The statistically significant differences were observed in the gestational week, body mass index, blood pressure, and incidence rates of proteinuria and lower extremity edema of pregnant women between the case group and the control group (p<0.05). Meanwhile, the genotype and allele distributions at rs2681472 in the case group were remarkably different from those of the control group (p<0.05). However, no evident differences were observed at rs17249754 between the two groups (p>0.05). According to univariate, multivariate, and logistic regression analyses, hypertension, and lower extremity edema were significantly associated with the incidence of eclampsia (p<0.05). In addition, the gene polymorphism at rs2681472 showed significant differences among subjects with and without hypertension and lower extremity edema (p<0.05). CONCLUSIONS: ATP2B1 gene polymorphism at rs2681472 shows significant differences between eclampsia patients and normal controls. Moreover, its gene polymorphism is closely related to the occurrence of hypertension and lower extremity edema.

[Association between both maternal and fetal angiotensinogen gene single nucleotide polymorphism and preeclampsia/eclampsia].

Objective: To explore the association between preeclampsia/eclampsia and maternal and fetal angiotensinogen SNPs. Methods: From January 2008 to October 2015, a case-parents/mother-control designed study was conducted among 347 preeclampsia/eclampsia cases and 700 controls to collect related information on their demographic characteristics and to detect the related angiotensinogen SNPs' genotypes. Both log-linear and unconditional logistic regression methods were employed to investigate the genetic effects of maternal/fetal angiotensinogen SNPs on preeclampsia/eclampsia. Multivariate binary unconditional logistic regression model and covariance were used to analyze the relationship between BMI before pregnancy, weight gain during pregnancy and overweight and obesity in preschool children. Results: Both fetal angiotensinogen rs3789679 GA and AA genotype were associated with the reduced risks of preeclampsia/eclampsia, with ORs as 0.73 (95%CI: 0.55-0.96) and 0.62 (95%CI: 0.39-0.98), respectively. For fetal angiotensinogen rs2493132, individuals that carrying the TT genotype, presented a positive association with the risk of preeclampsia/eclampsia, with OR as 1.60 (95%CI: 1.08-2.37). However, these associations were not statistically significant after the correction of the false discovery rate. It was observed that fetal rs3789679 could reduce the risk of preeclampsia/eclampsia (OR=0.73, 95%CI: 0.55-0.96) under the dominant model (GA+AA/GG) while fetal rs2493132 increased the risk of preeclampsia/eclampsia (OR=1.66, 95%CI: 1.13-2.44) under the recessive model (TT/CC+CT). Maternal rs5051 presented an association with preeclampsia/eclampsia (OR=1.33, 95%CI: 1.01-1.76) under the dominant model (TC+CC/TT). Conclusions: Results from the dominant model showed that both fetal rs3789679 GA and AA genotype reduced the risk of preeclampsia/eclampsia and maternal rs5051 TC while CC genotype increased the risk of preeclampsia/eclampsia. Fetal rs2493132 TT genotype seemed to be associated with the risk of preeclampsia/eclampsia under the recessive model.

Analysis on the correlations of ENOS and ET-2 gene polymorphisms with eclampsia.

OBJECTIVE: To explore the correlations of endothelial nitric oxide synthase (eNOS) G894T and endothelin-2 (ET-2) A985G gene polymorphisms with eclampsia. PATIENTS AND METHODS: A total of 110 eclampsia patients in our hospital from July 2014 to August 2017 were enrolled as the observation group and 100 healthy pregnant women in the same period as the control group. The polymorphisms of eNOS G894T and ET-2 A985G genes in the two groups were analyzed via polymerase chain reaction (PCR), and their correlations with eclampsia risk were investigated. RESULTS: The distribution frequency of eNOS G894T genotype TT and GT and T allele, as well as the ET-2 A985G genotype GG and AG and G allele, were evidently higher in the observation group than in the control group (p<0.05). ENOS G894T genotype TT and ET-2 A985G genotype GG were significantly associated with the occurrence of eclampsia. CONCLUSIONS: The polymorphisms of eNOS G894T and ET-2 A985G genes are correlated with the occurrence of eclampsia.

Correlation analysis between COX-2 gene polymorphism and eclampsia.

OBJECTIVE: The aim of this study was to investigate the expression of cyclooxygenase-2 (COX-2) in eclampsia patients, and to explore the correlation between COX-2 polymorphism and incidence of eclampsia. PATIENTS AND METHODS: From January 2016 to January 2018, a total of 280 pregnant women diagnosed in the Obstetrics and Gynecology Department of our hospital were selected for this study. All patients were divided into two groups, including normal pregnancy control group (n=120) and eclampsia group (n=160). The expression of COX-2 in placenta and umbilical cord tissues of eclampsia group and normal group was detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR), Western blotting and immunohistochemical staining. The single-nucleotide polymorphisms (rs1526172, rs1245231 and rs2198532) in the promoter region of the COX-2 gene were typed via conformation difference gel electrophoresis. Whether the distribution frequency of COX-2 genotypes met Hardy-Weinberg equilibrium law was detected via the Chi-square test. Meanwhile, the correlation between COX-2 alleles and gene polymorphisms and the incidence of eclampsia was analyzed. RESULTS: The messenger ribonucleic acid (mRNA) and protein expression levels of COX-2 in the eclampsia group were significantly higher than those of the normal group (p<0.05). According to the analysis, three polymorphisms of COX-2 gene were all in line with Hardy-Weinberg equilibrium distribution (p>0.05). Gene association analysis revealed that only polymorphisms (rs1526172 and rs1245231) and alleles were correlated with the incidence of eclampsia (p<0.05). However, polymorphism rs2198532 and alleles were not correlated with the incidence of eclampsia (p>0.05). CONCLUSIONS: Rs1526172 and rs1245231 in the promoter region of COX-2 are correlated with the incidence of eclampsia, while rs2198532 has no correlation with eclampsia.

Changes in the Expression of AQP4 and AQP9 in the Hippocampus Following Eclampsia-Like Seizure.

Eclampsia is a hypertensive disorder of pregnancy that is defined by the new onset of grand mal seizures on the basis of pre-eclampsia. Until now, the mechanisms underlying eclampsia were poorly understood. Brain edema is considered a leading cause of eclamptic seizures; aquaporins (AQP4 and AQP9), the glial water channel proteins mainly expressed in the nervous system, play an important role in brain edema. We studied AQP4 and AQP9 expression in the hippocampus of pre-eclamptic and eclamptic rats in order to explore the molecular mechanisms involved in brain edema. Using our previous animal models, we found several neuronal deaths in the hippocampal CA1 and CA3 regions after pre-eclampsia and that eclampsia induced more neuronal deaths in both areas by Nissl staining. In the current study, RT-PCR and Western blotting data showed significant upregulation of AQP4 and AQP9 mRNA and protein levels after eclamptic seizures in comparison to pre-eclampsia and at the same time AQP4 and AQP9 immunoreactivity also increased after eclampsia. These findings showed that eclamptic seizures induced cell death and that upregulation of AQP4 and AQP9 may play an important role in this pathophysiological process.

Distribution of HLA-G extended haplotypes and one HLA-E polymorphism in a large-scale study of mother-child dyads with and without severe preeclampsia and eclampsia.

The etiological pathways and pathogenesis of preeclampsia have rendered difficult to disentangle. Accumulating evidence points toward a maladapted maternal immune system, which may involve aberrant placental expression of immunomodulatory human leukocyte antigen (HLA) class Ib molecules during pregnancy. Several studies have shown aberrant or reduced expression of HLA-G in the placenta and in maternal blood in cases of preeclampsia compared with controls. Unlike classical HLA class Ia loci, the nonclassical HLA-G has limited polymorphic variants. Most nucleotide variations are clustered in the 5'-upstream regulatory region (5'URR) and 3'-untranslated regulatory region (3'UTR) of HLA-G and reflect a stringent expressional control. Based on genotyping and full gene sequencing of HLA-G in a large number of cases and controls (n > 900), the present study, which to our knowledge is the largest and most comprehensive performed, investigated the association between the HLA-G 14-bp ins/del (rs66554220) and HLA-E polymorphisms in mother and newborn dyads from pregnancies complicated by severe preeclampsia/eclampsia and from uncomplicated pregnancies. Furthermore, results from extended HLA-G haplotyping in the newborns are presented in order to assess whether a combined contribution of nucleotide variations spanning the 5'URR, coding region, and 3'UTR of HLA-G describes the genetic association with severe preeclampsia more closely. In contrast to earlier findings, the HLA-G 14-bp ins/del polymorphism was not associated with severe preeclampsia. Furthermore, the polymorphism (rs1264457) defining the two nonsynonymous HLA-E alleles, HLA-E*01:01:xx:xx and HLA-E*01:03:xx:xx, were not associated with severe preeclampsia. Finally, no specific HLA-G haplotypes were significantly associated with increased risk of developing severe preeclampsia/eclampsia.

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.

Maternal and fetal human leukocyte antigen class Ia and II alleles in severe preeclampsia and eclampsia.

A line of investigations indicate that genes in the human leukocyte antigen (HLA) complex are involved in a successful acceptance of the semiallogeneic fetus during pregnancy. In this study, associations between specific HLA class Ia (HLA-A and -B) and class II (HLA-DRB1, -DQA1, -DQB1, -DPA1 and -DPB1) alleles and the risk of developing severe preeclampsia/eclampsia were investigated in a detailed and large-scale study. In total, 259 women diagnosed with severe preeclampsia or eclampsia and 260 matched control women with no preeclampsia, together with their neonates, were included in the study. HLA genotyping for mothers and neonates was performed using next-generation sequencing. The HLA-DPB1*04:01:01G allele was significantly more frequent (Pc=0.044) among women diagnosed with severe preeclampsia/eclampsia compared with controls, and the DQA1*01:02:01G allele frequency was significantly lower (Pc=0.042) among newborns born by women with severe preeclampsia/eclampsia compared with controls. In mothers with severe preeclampsia/eclampsia, homozygosity was significantly more common compared with controls at the HLA-DPB1 locus (Pc=0.0028). Although the current large study shows some positive results, more studies, also with a functional focus, are needed to further clarify a possible role of the classical HLA genes in preeclampsia.

Reassessing the impact of smoking on preeclampsia/eclampsia: are there age and racial differences?

OBJECTIVE: To investigate the association between cigarette use during pregnancy and pregnancy-induced hypertension/preeclampsia/eclampsia (PIH) by maternal race/ethnicity and age. METHODS: This retrospective cohort study was based on the U.S. 2010 natality data. Our study sample included U.S. women who delivered singleton pregnancies between 20 and 44 weeks of gestation without major fetal anomalies in 2010 (n = 3,113,164). Multivariate logistic regression models were fit to estimate crude and adjusted odds ratios and the corresponding 95% confidence intervals. RESULTS: We observed that the association between maternal smoking and PIH varied by maternal race/ethnicity and age. Compared with non-smokers, reduced odds of PIH among pregnant smokers was only evident for non-Hispanic white and non-Hispanic American Indian women aged less than 35 years. Non-Hispanic Asian/Pacific Islander women who smoked during pregnancy had increased odds of PIH regardless of maternal age. Non-Hispanic white and non-Hispanic black women 35 years or older who smoked during pregnancy also had increased odds of PIH. CONCLUSION: Our study findings suggest important differences by maternal race/ethnicity and age in the association between cigarette use during pregnancy and PIH. More research is needed to establish the biologic and social mechanisms that might explain the variations with maternal age and race/ethnicity that were observed in our study.

Association of oxidative DNA damage, protein oxidation and antioxidant function with oxidative stress induced cellular injury in pre-eclamptic/eclamptic mothers during fetal circulation.

Pre-eclampsia is a devastating multi system syndrome and a major cause of maternal, fetal, neonatal morbidity and mortality. Pre-eclampsia is associated with oxidative stress in the maternal circulation. To have an insight on the effect of pre-eclampsia/eclampsia on the neonates, the study was made to explore the oxidative status by quantification of byproducts generated during protein oxidation and oxidative DNA damage and deficient antioxidant activity in umbilical cord blood of pre-eclamptic/eclamptic mothers during fetal circulation. Umbilical cord blood during delivery from neonates born to 19 pre-eclamptic mothers, 14 eclamptic mothers and 18 normotensive mothers (uncomplicated pregnancy) as control cases was collected. 8-OHdG (8-hydroxy-2-deoxyguanosine), protein carbonyl, nitrite, catalase, non-enzymatic antioxidants (vitamin A, E, C), total antioxidant status and iron status were determined. Significant elevation in the levels of 8-OHdG, protein carbonyl, nitrite and iron along with decreased levels of catalase, vitamin A, E, C, total antioxidant status were observed in the umbilical cord blood of pre-eclamptic and eclamptic pregnancies. These parameters might be influential variables for the risk of free radical damage in infants born to pre-eclamptic/eclamptic pregnancies. Increased oxidative stress causes oxidation of DNA and protein which alters antioxidant function. Excess iron level and decreased unsaturated iron binding capacity may be the important factor associated with oxidative stress and contribute in the pathogenesis of pre-eclampsia/eclampsia which is reflected in fetal circulation.

Venous thromboembolism does not share strong familial susceptibility with pre-eclampsia/eclampsia: a nationwide family study in Sweden.

OBJECTIVE: Genetic variants associated with venous thromboembolism (VTE) have been suggested to be involved in the pathogenesis of pre-eclampsia/eclampsia (PEC/EC). This nationwide study aimed to determine whether VTE shares familial susceptibility with PEC/EC. DESIGN: Population-based cohort study. SETTING: Sweden. SAMPLE: A total of 941 841 Swedish women delivering their first child between 1987 and 2008. METHODS: Data from the Swedish Multigeneration Register were linked to the Swedish Hospital Discharge Register. The risk of PEC/EC was determined in primiparous women with a family history of VTE (in parents and/or siblings), compared with primiparous women without a family history of VTE. Odds ratios (ORs) were calculated by logistic regression. MAIN OUTCOME MEASURE: PEC/EC in first pregnancy. RESULTS: In total, 43 621 women had PEC/EC in association with their first pregnancy. The OR for PEC/EC in women with a family history of VTE was 1.06 (95% CI 1.01-1.11); however, a family history of VTE was associated with higher odds of PEC/EC among women with previous hypertension (OR 1.38, 95% CI 1.25-1.52). CONCLUSION: A family history of VTE is weakly associated with PEC/EC risk, and is not clinically useful for the prediction of PEC/EC. The results of the present study suggest that it is unlikely that strong disease-causing mutations shared by VTE and PEC/EC are common in the Swedish population. The novel association between family history and PEC/EC among the subgroup with previous hypertension needs further confirmation in future studies.