Incident Coronary Heart Disease After Preeclampsia: Role of Reduced Fetal Growth, Preterm Delivery, and Parity.

BACKGROUND: Preeclampsia is a severe pregnancy disorder often complicated by reduced fetal growth or preterm delivery and is associated with long-term maternal morbidity and mortality. We aimed to assess the association between preeclampsia phenotypes and risk of subsequent coronary heart disease and maternal cardiovascular mortality. METHODS AND RESULTS: Women aged 16 to 49 years who gave birth during 1980-2002 and registered in the Medical Birth Registry of Norway were followed prospectively (1-29 years) for an incident major coronary event and mortality through linkage with the Cardiovascular Disease in Norway 1994-2009 (CVDNOR) project and the Norwegian Cause of Death Registry. Preeclampsia was subdivided based on the presence of a child born small for gestational age or preterm delivery. Among 506 350 women with 1 to 5 singleton births, there were 1275 (0.3%) occurrences of major coronary event, 468 (0.1%) cardiovascular deaths, and 5411 (1.1%) deaths overall. Compared with women without preeclampsia, the hazard ratio (95% CI) for major coronary event was 2.1 (1.73-2.65) after preeclampsia alone, 3.3 (2.37-4.57) after preeclampsia in combination with small for gestational age, and 5.4 (3.74-7.74) after preeclampsia in combination with preterm delivery. Analyses distinguishing women with 1 (n=61 352) or >1 (n=281 069) lifetime pregnancy and analyses with cardiovascular mortality as outcome followed the same pattern. CONCLUSIONS: The occurrence of major coronary events was increased among women with preeclampsia and highest for preeclampsia combined with a child born small for gestational age and/or preterm delivery.

The antihypertensive MTHFR gene polymorphism rs17367504-G is a possible novel protective locus for preeclampsia.

OBJECTIVE: Preeclampsia is a complex heterogeneous disease commonly defined by new-onset hypertension and proteinuria in pregnancy. Women experiencing preeclampsia have increased risk for cardiovascular diseases (CVD) later in life. Preeclampsia and CVD share risk factors and pathophysiologic mechanisms, including dysregulated inflammation and raised blood pressure. Despite commonalities, little is known about the contribution of shared genes (pleiotropy) to these diseases. This study aimed to investigate whether genetic risk factors for hypertension or inflammation are pleiotropic by also being associated with preeclampsia. METHODS: We genotyped 122 single nucleotide polymorphisms (SNPs) in women with preeclampsia (n = 1006) and nonpreeclamptic controls (n = 816) from the Norwegian HUNT Study. SNPs were chosen on the basis of previously reported associations with either nongestational hypertension or inflammation in genome-wide association studies. The SNPs were tested for association with preeclampsia in a multiple logistic regression model. RESULTS: The minor (G) allele of the intronic SNP rs17367504 in the gene methylenetetrahydrofolate reductase (MTHFR) was associated with a protective effect on preeclampsia (odds ratio 0.65, 95% confidence interval 0.53-0.80) in the Norwegian cohort. This association did not replicate in an Australian preeclampsia case-control cohort (P = 0.68, odds ratio 1.05, 95% confidence interval 0.83-1.32, minor allele frequency = 0.15). CONCLUSION: MTHFR is important for regulating transmethylation processes and is involved in regulation of folate metabolism. The G allele of rs17367504 has previously been shown to protect against nongestational hypertension. Our study suggests a novel association between this allele and reduced risk for preeclampsia. This is the first study associating the minor (G) allele of a SNP within the MTHFR gene with a protective effect on preeclampsia, and in doing so identifying a possible pleiotropic protective effect on preeclampsia and hypertension.

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

BACKGROUND: Preeclampsia is a major pregnancy complication without curative treatment available. A Norwegian Preeclampsia Family Cohort was established to provide a new resource for genetic and molecular studies aiming to improve the understanding of the complex pathophysiology of preeclampsia. METHODS: Participants were recruited from five Norwegian hospitals after diagnoses of preeclampsia registered in the Medical birth registry of Norway were verified according to the study's inclusion criteria. Detailed obstetric information and information on personal and family disease history focusing on cardiovascular health was collected. At attendance anthropometric measurements were registered and blood samples were drawn. The software package SPSS 19.0 for Windows was used to compute descriptive statistics such as mean and SD. P-values were computed based on t-test statistics for normally distributed variables. Nonparametrical methods (chi square) were used for categorical variables. RESULTS: A cohort consisting of 496 participants (355 females and 141 males) representing 137 families with increased occurrence of preeclampsia has been established, and blood samples are available for 477 participants. Descriptive analyses showed that about 60% of the index women's pregnancies with birth data registered were preeclamptic according to modern diagnosis criteria. We also found that about 41% of the index women experienced more than one preeclamptic pregnancy. In addition, the descriptive analyses confirmed that preeclamptic pregnancies are more often accompanied with delivery complications. CONCLUSION: The data and biological samples collected in this Norwegian Preeclampsia Family Cohort will provide an important basis for future research. Identification of preeclampsia susceptibility genes and new biomarkers may contribute to more efficient strategies to identify mothers "at risk" and contribute to development of novel preventative therapies.

Metabolic profiles of placenta in preeclampsia using HR-MAS MRS metabolomics.

INTRODUCTION: Preeclampsia is a heterogeneous gestational disease characterized by maternal hypertension and proteinuria, affecting 2-7% of pregnancies. The disorder is initiated by insufficient placental development, but studies characterizing the placental disease components are lacking. METHODS: Our aim was to phenotype the preeclamptic placenta using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS MRS). Placental samples collected after delivery from women with preeclampsia (n = 19) and normotensive pregnancies (n = 15) were analyzed for metabolic biomarkers including amino acids, osmolytes, and components of the energy and phospholipid metabolism. The metabolic biomarkers were correlated to clinical characteristics and inflammatory biomarkers in the maternal sera. RESULTS: Principal component analysis showed inherent differences in placental metabolic profiles between preeclamptic and normotensive pregnancies. Significant differences in metabolic profiles were found between placentas from severe and non-severe preeclampsia, but not between preeclamptic pregnancies with fetal growth restricted versus normal weight neonates. The placental metabolites correlated with the placental stress marker sFlt-1 and triglycerides in maternal serum, suggesting variation in placental stress signaling between different placental phenotypes. DISCUSSION: HR-MAS MRS is a sensitive method for defining the placental disease component of preeclampsia, identifying several altered metabolic pathways. Placental HR-MAS MRS analysis may improve insight into processes affected in the preeclamptic placenta, and represents a novel long-required tool for a sensitive placental phenotyping of this heterogeneous disease.

First Trimester Urine and Serum Metabolomics for Prediction of Preeclampsia and Gestational Hypertension: A Prospective Screening Study.

Hypertensive disorders of pregnancy, including preeclampsia, are major contributors to maternal morbidity. The goal of this study was to evaluate the potential of metabolomics to predict preeclampsia and gestational hypertension from urine and serum samples in early pregnancy, and elucidate the metabolic changes related to the diseases. Metabolic profiles were obtained by nuclear magnetic resonance spectroscopy of serum and urine samples from 599 women at medium to high risk of preeclampsia (nulliparous or previous preeclampsia/gestational hypertension). Preeclampsia developed in 26 (4.3%) and gestational hypertension in 21 (3.5%) women. Multivariate analyses of the metabolic profiles were performed to establish prediction models for the hypertensive disorders individually and combined. Urinary metabolomic profiles predicted preeclampsia and gestational hypertension at 51.3% and 40% sensitivity, respectively, at 10% false positive rate, with hippurate as the most important metabolite for the prediction. Serum metabolomic profiles predicted preeclampsia and gestational hypertension at 15% and 33% sensitivity, respectively, with increased lipid levels and an atherogenic lipid profile as most important for the prediction. Combining maternal characteristics with the urinary hippurate/creatinine level improved the prediction rates of preeclampsia in a logistic regression model. The study indicates a potential future role of clinical importance for metabolomic analysis of urine in prediction of preeclampsia.

Distinct First Trimester Cytokine Profiles for Gestational Hypertension and Preeclampsia.

OBJECTIVE: Gestational hypertension and preeclampsia involve dysregulated maternal inflammatory responses to pregnancy, but whether such responses differ between the disorders has not been determined. We aimed to investigate disease-specific early pregnancy serum cytokine profiles of women subsequently developing gestational hypertension or preeclampsia for new insight into the underlying pathogeneses and differences between the disorders. APPROACH AND RESULTS: The study cohort consisted of 548 pregnant Norwegian women who were either multiparous with previous gestational hypertension or preeclampsia or were nulliparous. Maternal sera at gestational weeks 11(0)-13(6) were assayed for 27 cytokines, C-reactive protein, total cholesterol, high-density lipoprotein, triglyceride, creatinine, calcium, uric acid, and placental growth factor. Compared with normotensive women, women with both hypertensive conditions presented an atherogenic lipid profile at early gestation, but only those later developing gestational hypertension had significantly higher serum levels of interleukin (IL)-5 and IL-12. Comparing the 2 hypertensive pregnancy disorders, women subsequently developing gestational hypertension had higher serum levels of IL-1ß, IL-5, IL-7, IL-8, IL-13, basic fibroblast growth factor, and vascular endothelial growth factor than the women subsequently developing preeclampsia. CONCLUSIONS: This study identifies early pregnancy differences in serum cytokine profiles for gestational hypertension and preeclampsia.

Refined phenotyping identifies links between preeclampsia and related diseases in a Norwegian preeclampsia family cohort.

OBJECTIVE: Preeclampsia is a complex genetic disease of pregnancy with a heterogenous presentation, unknown cause and potential severe outcomes for both mother and child. Preeclamptic women have increased risk for atherothrombotic cardiovascular disease. We aimed to identify heritabilities and phenotypic correlations of preeclampsia and related conditions in the Norwegian Preeclampsia Family Biobank. METHODS: By applying a variance components model, a total of 493 individuals (from 138 families with increased occurrence of preeclampsia) were classified according to 30 disease-related phenotypes. RESULTS: Of parous women, 75.7% (263/338) had experienced preeclampsia and 35.7% of women with and 22.4% without preeclampsia delivered children small for gestational age (SGA). We identified 11 phenotypes as heritable. The increased occurrence of preeclampsia was reflected by the presence [heritability (H2r) = 0.60)] and severity (H2r = 0.15) of preeclampsia and being born in a preeclamptic pregnancy (H2r = 0.25). Other heritable phenotypes identified included SGA (H2r = 0.40), chronic hypertension (H2r = 0.57), severity of atherothrombotic cardiovascular disease (H2r = 0.31), BMI (H2r = 0.60) and pulmonary disease (H2r = 0.91). The heritable phenotype preeclampsia overlapped with SGA (P = 0.03), whereas pulmonary disease was phenotypically correlated with atherothrombotic cardiovascular disease (P < 0.01), SGA (P = 0.02) and BMI (P = 0.02). CONCLUSION: This is the first study identifying the H2r of a range of health-related conditions in preeclamptic families. Our study demonstrates how refinement of phenotypes leads to better H2r estimation and the identification of a biological relationship between preeclampsia and related traits.

Functional Toll-like receptors in primary first-trimester trophoblasts.

Toll-like receptors (TLRs) are an important part of the body's danger response system and crucial for initiating inflammation in response to cellular stress, tissue damage, and infections. Proper placental development is sensitive to inflammatory activation, and a role for TLRs in trophoblast immune activation has been suggested, but no overall examination has been performed in primary trophoblasts of early pregnancy. This study aimed to broadly examine cell surface and endosomal TLR gene expression and activation in first-trimester trophoblasts. Gene expression of all ten TLRs was examined by quantitative RT-PCR (RT-qPCR) in primary first-trimester trophoblasts (n = 6) and the trophoblast cell line BeWo, and cytokine responses to TLR ligands were detected by quantitative multiplex immunoassay. Primary first-trimester trophoblasts broadly expressed all ten TLR mRNAs; TLR1, TLR2, TLR3, TLR4, and TLR6 mRNA were expressed by all primary trophoblast populations, while TLR5, TLR7, TLR8, TLR9, and TLR10 mRNA expression was more restricted. Functional response to ligand activation of cell surface TLR2/1, TLR4, and TLR5 increased IL-6 and/or IL-8 release (P < 0.01) from primary trophoblasts. For endosomal TLRs, TLR3 and TLR9 ligand exposure increased receptor-specific production of IL-8 (P < 0.01) and IFN-γ-induced protein 10 (IP-10; P < 0.001) or vascular endothelial growth factor A (VEGFA; P < 0.01). In contrast, BeWo cells expressed lower TLR mRNA levels and did not respond to TLR activation. In conclusion, primary first-trimester trophoblasts broadly express functional TLRs, with inter-individual variation, suggesting that trophoblast TLR2, TLR3, TLR4, TLR5, and TLR9 might play a role in early placental inflammation.

Metabolomic biomarkers in serum and urine in women with preeclampsia.

OBJECTIVE: To explore the potential of magnetic resonance (MR) metabolomics for study of preeclampsia, for improved phenotyping and elucidating potential clues to etiology and pathogenesis. METHODS: Urine and serum samples from pregnant women with preeclampsia (n = 10), normal pregnancies (n = 10) and non-pregnant women (n = 10) matched by age and gestational age were analyzed with MR spectroscopy and subjected to multivariate analysis. Metabolites were then quantified and compared between groups. RESULTS: Urine and serum samples revealed clear differences between women with preeclampsia and both control groups (normal pregnant and non-pregnant women). Nine urine metabolites were significantly different between preeclampsia and the normal pregnant group. Urine samples from women with early onset preeclampsia clustered together in the multivariate analysis. The preeclampsia serum spectra showed higher levels of low and very-low density lipoproteins and lower levels of high-density lipoproteins when compared to both non-pregnant and normal pregnant women. CONCLUSION: The MR determined metabolic profiles in urine and serum from women with preeclampsia are clearly different from normal pregnant women. The observed differences represent a potential to examine mechanisms underlying different preeclampsia phenotypes in urine and serum samples in larger studies. In addition, similarities between preeclampsia and cardiovascular disease in metabolomics are demonstrated.

Preeclampsia and cardiovascular disease share genetic risk factors on chromosome 2q22.

OBJECTIVE: Four putative single nucleotide polymorphism (SNP) risk variants at the preeclampsia susceptibility locus on chromosome 2q22; rs2322659 (LCT), rs35821928 (LRP1B), rs115015150 (RND3) and rs17783344 (GCA), were recently shown to associate with known cardiovascular risk factors in a Mexican American cohort. This study aimed to further evaluate the pleiotropic effects of these preeclampsia risk variants in an independent Australian population-based cohort. METHODS: The four SNPs were genotyped in the Western Australian Pregnancy Cohort (Raine) Study that included DNA, clinical and biochemical data from 1246 mothers and 1404 of their now adolescent offspring. Genotype association analyses were undertaken using the SOLAR software. RESULTS: Nominal associations (P<0.05) with cardiovascular risk factors were detected for all four SNPs. The LCT SNP was associated with decreased maternal height (P=0.005) and decreased blood glucose levels in adolescents (P=0.022). The LRP1B SNP was associated with increased maternal height (P=0.026) and decreased maternal weight (P=0.044). The RND3 SNP was associated with decreased triglycerides in adolescents (P=0.001). The GCA SNP was associated with lower risk in adolescents to be born of a preeclamptic pregnancy (P=0.003) and having a mother with prior preeclamptic pregnancy (P=0.033). CONCLUSIONS: Our collective findings support the hypothesis that genetic mechanisms for preeclampsia and CVD are, at least in part, shared, but need to be interpreted with some caution as a Bonferroni correction for multiple testing adjusted the statistical significance threshold (adjusted P<0.001).

Changing patterns of cytomegalovirus seroprevalence among pregnant women in Norway between 1995 and 2009 examined in the Norwegian Mother and Child Cohort Study and two cohorts from Sor-Trondelag County: a cross-sectional study.

OBJECTIVES: To examine cytomegalovirus (CMV) seroprevalence and associated risk factors for CMV seropositivity in pregnant Norwegian women. DESIGN: Cross-sectional study. SETTING: The Norwegian Mother and Child Cohort Study (MoBa) in addition to two random samples of pregnant women from Sør-Trøndelag County in Norway. PARTICIPANTS: Study group 1 were 1000 pregnant women, randomly selected among 46 127 pregnancies in the MoBa (1999-2006) at 17/18 week of gestation. Non-ethnic Norwegian women were excluded. Study groups 2 (n=1013 from 1995) and 3 (n=979 from 2009) were pregnant women at 12 weeks of gestation from Sør-Trøndelag County. OUTCOME MEASURES: CMV seropositivity in blood samples from pregnant Norwegian women. RESULTS: CMV-IgG antibodies were detected in 59.9% and CMV-IgM antibodies in 1.3% of pregnant Norwegian women in study group 1. Women from North Norway demonstrated a higher CMV-IgG seroprevalence (72.1%) than women from South Norway (58.5%) (OR 1.83, 95% CI 1.17 to 2.88). The CMV-IgG seroprevalence was higher among women with low education (70.5%) compared to women with higher education (OR 2.20, 95% CI 1.24 to 3.90). Between 1995 and 2009 the CMV-IgG seroprevalence increased from 63.1% to 71.4% in pregnant women from Sør-Trøndelag County (study groups 2 and 3; p<0.001). The highest CMV-IgG seroprevalence (79.0%) was observed among the youngest pregnant women (<25 years) from Sør-Trøndelag County in 2009 (study group 3). CONCLUSIONS: The CMV-IgG seroprevalence of pregnant Norwegian women varies with geographic location and educational level. Additionally, the CMV-IgG seroprevalence appears to have increased over the last years, particularly among young pregnant women.

Mediators of the association between pre-eclampsia and cerebral palsy: population based cohort study.

OBJECTIVE: To test the hypothesis that pre-eclampsia is a risk factor for cerebral palsy mediated through preterm birth and being born small for gestational age. DESIGN: Population based cohort study. SETTING: Clinical data from the Norwegian Cerebral Palsy Registry were linked with perinatal data prospectively recorded by the Medical Birth Registry of Norway. PARTICIPANTS: All singleton babies who survived the neonatal period during 1996-2006 (849 children with cerebral palsy and 616,658 control children). MAIN OUTCOME MEASURES: Cerebral palsy and cerebral palsy subtypes. RESULTS: Children exposed to pre-eclampsia had an excess risk of cerebral palsy (unadjusted odds ratio 2.5, 95% confidence interval 2.0 to 3.2) compared with unexposed children. Among children born at term (≥ 37 weeks), exposure to pre-eclampsia was not associated with an excess risk of cerebral palsy in babies not born small for gestational age (1.2, 0.7 to 2.0), whereas children exposed to pre-eclampsia and born small for gestational age had a significantly increased risk of cerebral palsy (3.2, 1.5 to 6.7). Non-small for gestational age babies born very preterm (<32 weeks) and exposed to pre-eclampsia had a reduced risk of cerebral palsy compared with unexposed children born at the same gestational age (0.5, 0.3 to 0.8), although the risk was not statistically significantly reduced among children exposed to pre-eclampsia and born small for gestational age (0.7, 0.4 to 1.3). Exposure to pre-eclampsia was not associated with a specific cerebral palsy subtype. CONCLUSIONS: Exposure to pre-eclampsia was associated with an increased risk of cerebral palsy, and this association was mediated through the children being born preterm or small for gestational age, or both. Among children born at term, pre-eclampsia was a risk factor for cerebral palsy only when the children were small for gestational age.

Validity of the diagnosis of pre-eclampsia in the Medical Birth Registry of Norway.

OBJECTIVE: Evaluating the validity of pre-eclampsia registration in the Medical Birth Registry of Norway (MBRN) according to both broader and restricted disease definitions. DESIGN: Retrospective nested cohort study. SETTING: Multicenter study. POPULATION: In this study, two cohorts of women with pre-eclamptic pregnancies registered in the MBRN were selected. Study group 1 contained 966 pregnancies from 1967 to 2002. Concomitant participation in the Nord-Trøndelag Health Study 2 was required. Study group 2 comprised 1138 pregnancies recorded in 1967-2005, examined as a pre-eclampsia biobank was established. METHODS: Diagnostic criteria vary. The broader criteria for pre-eclampsia, used by the MBRN, are one measurement of hypertension and proteinuria (Criterion A). Criteria used internationally today require two measurements of hypertension and proteinuria (Criterion B). The diagnostic validities in Study groups 1 and 2 were judged against medical records according to Criterion A and B, respectively. MAIN OUTCOME MEASURES: Positive predictive value (PPV) and trend analyses. RESULTS: The diagnosis was confirmed in 88.3% of pregnancies in Study group 1, and in 63.6% in Study group 2. PPV was high for Study group 1 throughout the period. For Study group 2, results improved significantly after 1986. CONCLUSIONS: This study ascertains high PPV of pre-eclampsia in the MBRN using broader traditional criteria, although the PPV decreases through assessment using restricted modern criteria. This illustrates how inclusion of direct measurements may improve registration of complex disorders defined by changing diagnostic criteria.

Genetic dissection of the pre-eclampsia susceptibility locus on chromosome 2q22 reveals shared novel risk factors for cardiovascular disease.

Pre-eclampsia is an idiopathic pregnancy disorder promoting morbidity and mortality to both mother and child. Delivery of the fetus is the only means to resolve severe symptoms. Women with pre-eclamptic pregnancies demonstrate increased risk for later life cardiovascular disease (CVD) and good evidence suggests these two syndromes share several risk factors and pathophysiological mechanisms. To elucidate the genetic architecture of pre-eclampsia we have dissected our chromosome 2q22 susceptibility locus in an extended Australian and New Zealand familial cohort. Positional candidate genes were prioritized for exon-centric sequencing using bioinformatics, SNPing, transcriptional profiling and QTL-walking. In total, we interrogated 1598 variants from 52 genes. Four independent SNP associations satisfied our gene-centric multiple testing correction criteria: a missense LCT SNP (rs2322659, P = 0.0027), a synonymous LRP1B SNP (rs35821928, P = 0.0001), an UTR-3 RND3 SNP (rs115015150, P = 0.0024) and a missense GCA SNP (rs17783344, P = 0.0020). We replicated the LCT SNP association (P = 0.02) and observed a borderline association for the GCA SNP (P = 0.07) in an independent Australian case-control population. The LRP1B and RND3 SNP associations were not replicated in this same Australian singleton cohort. Moreover, these four SNP associations could not be replicated in two additional case-control populations from Norway and Finland. These four SNPs, however, exhibit pleiotropic effects with several quantitative CVD-related traits. Our results underscore the genetic complexity of pre-eclampsia and present novel empirical evidence of possible shared genetic mechanisms underlying both pre-eclampsia and other CVD-related risk factors.

OP004. A SNP associated with susceptibility to preeclampsia near the inhibin, beta B gene, is also associated with cardiovascular disease risk traits.

INTRODUCTION: It is well established that preeclampsia (PE) increases later life cardiovascular disease (CVD) risk. Consequently, PE has started to gain a role as an early screening criterion for CVD. PE and CVD share several risk factors, pathological features and metabolic abnormalities. These common antecedents have drawn attention to the likelihood of shared genetic susceptibility. OBJECTIVES: Results from our previous PE GWAS identified a significant association with the rs7579169 SNP and maternal PE susceptibility (odds ratio 1.57). This SNP resides near the Inhibin, beta B (INHBB) gene on chromosome 2q14. Therefore, this study sought to interrogate this PE susceptibility SNP against several CVD risk traits in an effort to highlight additional empirical evidence of likely shared PE/CVD genetic mechanisms. METHODS: The rs7579169 SNP was genotyped in a large independent Australian cohort rich in quantitative CVD risk traits; The Western Australian Pregnancy Cohort (Raine) Study. This cohort comprises of fasting blood samples from 1246 mothers and 1461 adolescents (14- and 17-year-old) and clinical parameters pertaining, but not limited, to anthropometric measures of adiposity and lipid-related measures. Genetic association analyses of rs7579169 against the Raine CVD-related risk traits were performed using the software package R. All statistical analyses assumed an additive model of gene action. RESULTS: Significant associations (p<0.05) for rs7579169 with CVD-related risk traits were detected, both for the mothers and the adolescents. Specifically, the minor rs7579169-T allele (MAF 0.400) was found to be significantly associated with elevated levels of triglycerides, total and LDL cholesterol, a greater average waist:hip circumference ratio and a greater average hip circumference. CONCLUSION: We have previously identified rs7579169 located near the INHBB gene on chromosome 2q14 to significantly associate with maternal PE susceptibility. We have now demonstrated that this SNP is also significantly associated with several CVD-related risk traits in an independent Caucasian population. We hereby present additional empirical evidence of possible shared genetic risk factors underlying both PE and CVD related traits.

OP006. A preeclampsia genome-wide linkage scan in norwegian families.

INTRODUCTION: Several maternal susceptibility loci for preeclampsia (PE) have been discovered amongst Icelandic, Australian/New Zealand, Dutch and Finnish family cohorts, implicating locus heterogeneity. Through candidate gene studies, allele-specific heterogeneity in different populations is also evident. It is therefore likely that numerous population specific PE susceptibility variants exist, differing in their effect size. Despite on-going efforts to identify susceptibility genes for PE, the causal genetic variants still remain obscure. OBJECTIVES: The aim of this study is to interrogate the genetic architecture of PE susceptibility by performing a genome-wide linkage scan in a novel familial cohort from Norway. METHODS: A total of 480 DNA samples from The Norwegian PE Family Biobank were genotyped at Genomic Core Facility at NTNU. Genome-wide genotyping was performed with the Infinium HumanExome BeadChip (>240,000 markers) (Illumina, USA) that delivers focused coverage of exonic regions of the human genome. RESULTS: A total of 137 families are represented with 222 women with a valid PE diagnosis (SBP⩾140mmHg DBP⩾90mmHg, ⩾2 measurements at least 4h apart with documented proteinuria at ⩾2 occasions occurring after 20weeks of pregnancy), 44 with self-reported PE and 72 women with a healthy pregnancy. The genotyping has just recently been completed with an average call rate of 99.96%. Data and statistical analysis is now underway using MERLIN, R and SOLAR. A description of the Norwegian PE familial cohort plus preliminary results will be presented at the Congress. CONCLUSION: To our knowledge this is the first SNP-based genome-wide linkage study on PE, and the first performed in a novel Norwegian PE family cohort. By using an approach focusing on functionally relevant markers we anticipate the identification of susceptibility loci that are of substantial importance for disease development.

PP002. Metabolomic biomarkers in serum and urine of preeclamptic women.

INTRODUCTION: Preeclampsia (PE) affects about 3% of pregnancies. The syndrome cannot be accurately predicted, and large variation complicates the search for early biomarkers. Metabolites are components of the metabolism; the chemical interactions in the body necessary for life. Metabolomics, the study of metabolism, has been used to characterize diabetes, cancer and cardiovascular disease (CVD). OBJECTIVES: Explore the use of magnetic resonance (MR) metabolomics on PE, and to elucidate potential clues to PE etiology and pathogenesis. METHODS: Serum and urine from non-pregnant women (n=10) and pregnant women with PE (n=10) or normal pregnancies (n=10), was analyzed with MR spectroscopy and subjected to multivariate analysis (MVA). Metabolites were quantified and compared between groups. RESULTS: Urine and serum samples revealed differences between PE and both control groups. Ten urine metabolites were significantly different between the three groups. Urine samples from women with early-onset PE clustered together in MVA. PE serum spectra had higher levels of low and very-low density lipoproteins, and lower high-density lipoproteins compared to control groups. CONCLUSION: PE and control samples were effectively discriminated using MR metabolomics, suggesting that MR metabolomics is a useful method for improved sub-phenotyping of PE in larger studies. Information relevant to the disease was found both for serum and urine samples, and indicated similarities between PE and CVD.

PP040. Activation of endosomal toll-like receptors in first trimester trophoblasts.

INTRODUCTION: A mild systemic inflammation may be beneficial to normal pregnancy, however exaggerated inflammation may contribute to pregnancy complications. Infections and cell stress or damage may evoke placental inflammation by activation of Toll-like receptors (TLRs). TLR3, TLR7, TLR8 and TLR9 are located intracellulary on endosomes and are activated by nucleic acids from microbes and damaged cells. Trophoblasts play a crucial role during placentation, and the role of TLRs in first trimester trophoblasts needs to be determined. OBJECTIVES: To characterize endosomal TLR gene expression and activation in first trimester trophoblasts, to extend knowledge of endosomal TLR involvement in placental inflammation. METHODS: Primary trophoblasts were isolated from six first trimester placentas by enzyme degradation and gradient centrifugation. Gene expression of TLR3, TLR7, TLR8 and TLR9 in primary first trimester trophoblasts and the trophoblast cell line BeWo was quantified by RT-qPCR. The trophoblasts were stimulated with ligands for endosomal TLRs, and release of pro-inflammatory cytokines was analyzed by multiplex. RESULTS: Primary first trimester trophoblasts showed gene expression of all endosomal TLRs, and endosomal TLR activation gave increased production of the pro-inflammatory cytokines IL-6, IL-8, and IP-10. CONCLUSION: Primary first trimester trophoblasts express functional endosomal TLRs, indicating TLR-mediated trophoblast involvement in early placental inflammation.

PP042. Cell surface toll-like receptors in primary first trimester trophoblasts.

INTRODUCTION: The first trimester of pregnancy is characterised by a mild pro-inflammatory environment, however excessive inflammation threatens placental development and function. Toll-like receptors (TLRs) are crucial in initiating inflammation. TLR1, TLR2, TLR4, TLR5, TLR6 and TLR10 are expressed on the cell surface, and respond to microbial infection and cell damage and stress signals. Recent findings of TLRs in trophoblasts indicate a role in inflammation during pregnancy, but further studies are warranted. OBJECTIVES: To investigate gene expression and function of cell surface TLRs in first trimester trophoblasts, to extend knowledge on the role of trophoblast TLRs during placental development. METHODS: Primary trophoblasts were isolated from first trimester placentas (n=6) by enzyme degradation and density gradient centrifugation. Gene expression of TLR1, TLR2, TLR4, TLR5, TLR6 and TLR10 was quantified by RT-qPCR in primary first trimester trophoblasts and the trophoblast cell line BeWo. Trophoblasts were stimulated with cell surface TLR ligands and pro-inflammatory cytokine release was analysed by multiplex immunoassay. RESULTS: Primary first trimester trophoblasts expressed all cell surface TLR mRNAs, and activation of TLR2/1, TLR4 and TLR5 induced IL-6 and/or IL-8. CONCLUSION: The broad expression of functional cell surface TLRs in primary first trimester trophoblasts suggests a central role for trophoblasts in placental inflammation and immune activation.

Genome-wide association scan identifies a risk locus for preeclampsia on 2q14, near the inhibin, beta B gene.

Elucidating the genetic architecture of preeclampsia is a major goal in obstetric medicine. We have performed a genome-wide association study (GWAS) for preeclampsia in unrelated Australian individuals of Caucasian ancestry using the Illumina OmniExpress-12 BeadChip to successfully genotype 648,175 SNPs in 538 preeclampsia cases and 540 normal pregnancy controls. Two SNP associations (rs7579169, p = 3.58×10(-7), OR = 1.57; rs12711941, p = 4.26×10(-7), OR = 1.56) satisfied our genome-wide significance threshold (modified Bonferroni p<5.11×10(-7)). These SNPs reside in an intergenic region less than 15 kb downstream from the 3' terminus of the Inhibin, beta B (INHBB) gene on 2q14.2. They are in linkage disequilibrium (LD) with each other (r(2) = 0.92), but not (r(2)<0.80) with any other genotyped SNP ±250 kb. DNA re-sequencing in and around the INHBB structural gene identified an additional 25 variants. Of the 21 variants that we successfully genotyped back in the case-control cohort the most significant association observed was for a third intergenic SNP (rs7576192, p = 1.48×10(-7), OR = 1.59) in strong LD with the two significant GWAS SNPs (r(2)>0.92). We attempted to provide evidence of a putative regulatory role for these SNPs using bioinformatic analyses and found that they all reside within regions of low sequence conservation and/or low complexity, suggesting functional importance is low. We also explored the mRNA expression in decidua of genes ±500 kb of INHBB and found a nominally significant correlation between a transcript encoded by the EPB41L5 gene, ∼250 kb centromeric to INHBB, and preeclampsia (p = 0.03). We were unable to replicate the associations shown by the significant GWAS SNPs in case-control cohorts from Norway and Finland, leading us to conclude that it is more likely that these SNPs are in LD with as yet unidentified causal variant(s).