Fetal Heart Development Research Articles

Prenatal hypoxia-induced epigenomic and transcriptomic reprogramming in rat fetal and adult offspring hearts

The molecular mechanism of antenatal hypoxia impacting on fetal heart development and elevated risk of heart disease of adult offspring is poorly understood. We present a dataset integrating DNA methylome and transcriptome analyses of antenatal hypoxia affecting rat fetal and adult offspring hearts to understand hypoxia-mediated epigenomic reprogramming of the heart development. We showed that antenatal hypoxia not only induced DNA methylomic and transcriptomic changes in the fetal hearts, but also had a delayed and lasting effect on the adult offspring hearts. Of interest, antenatal hypoxia induced opposite changes in DNA methylation patterns in fetal and adult hearts, with a hypermethylation in the fetus and a hypomethylation in the adult. An extensive preprocessing, quality assessment, and downstream data analyses were performed on the genomic dataset so that the research community may take advantage of the public resource. These dataset could be exploited as a comprehensive resource for understanding fetal hypoxia-mediated epigenetic reprogramming in the heart development and further developmental programming of heart vulnerability to disease later in life.Figshare doi: https://doi.org/10.6084/m9.figshare.9948572

Characterizing the effects of in utero exposure to valproic acid on murine fetal heart development.

Recently, the use of the antiepileptic drug valproic acid (VPA) for the treatment of psychiatric conditions has been on the rise. However, studies have shown that in utero VPA exposure can affect embryonic development, including being associated with congenital heart defects. One proposed mechanism of VPA-initiated teratogenicity is the inhibition of histone deacetylase, which is involved in the regulation of transcription factors that regulate cardiogenesis. Myocyte enhancing factor 2C (Mef2c), a transcription factor involved in the development of cardiac structure and cardiomyocyte differentiation, has been shown to increase in response to in utero VPA exposure, associating with contractile dysfunction and myocardial disorganization. To characterize the effects of VPA on murine heart development, pregnant CD-1 mice were dosed with 400 mg/kg of VPA on gestational day (GD) 9. Using high-resolution ultrasound, we examined the effects of VPA on cardiac contractile function on GD 14-18, with fetal hearts being harvested on GD 19 for histological analysis. Lastly, we conducted quantitative real-time polymerase chain reaction to measure the relative Mef2c gene expression in GD 16 murine hearts. We observed structural anomalies at GD 19 in the hearts of VPA-treated mice. Additionally, our results showed alterations in measures of cardiac contractility, with a decrease or increase in cardiac contractile ability in VPA-treated mice depending on the GD and measurement taken. These results further characterize the effects of VPA on heart development and suggest that alterations in Mef2c gene expression, at least on GD 16, do not mediate VPA-induced cardiotoxicity in CD-1 mice.

SEX-DIFFERENCES IN FETAL PROGRAMMING OF CARDIOMYOPATHY INDUCED BY HYPERTENSIVE DISORDERS OF PREGNANCY IN MICE

Hypertensive disorders can reach one in ten pregnancies worldwide. They account for a quarter of all preterm births and low birth weight, significantly increasing rates of maternal and neonatal morbidity and mortality Children born to hypertensive pregnancies can develop special clinical features that are consistent with a preterm or accelerated aging process with signs of cardiac remodeling as early as childhood. Significant heart shape and ventricular geometrical alterations have been described in growth-restricted fetuses of hypertensive pregnancies suggesting an extended impact on fetal heart development and programming of heart diseases. The aim of this study was to develop a new ultrasound imaging protocol to describe, for the first time in a genetic mice model of maternal hypertension and superposed preeclampsia, sex-differences in the fetal programming of cardiomyopathy. We have performed echocardiography imaging in fetuses of n=4/group transgenic pregnant mice overexpressing human renin and angiotensinogen and controls (C57BL/6) at 18.5 gestational days. Fetal images were adjusted by intracranial diameter as a surrogate intrauterine marker of fetal growth. Genotype-negative offspring were followed up to 40-day postnatal, when echocardiography was performed in male and female offspring (n=8/group) of control and transgenic mothers. Data are presented as average±SD of control vs hypertensive-pregnancies, compared using student t-test. Fetuses of hypertensive mothers have larger LV mass (3.2±0.4 vs 4.3±0.3 mg, P < .001) with thicker LV walls (0.32±0.02 vs 0.45±0.04 mm, P < .01) and dilated chamber (0.82±0.02 vs 0.97±0.07 mm, P < .01) compared to fetuses of control mothers, these parameters remaining significant after adjusting by intracranial diameter. Into adulthood, both male and female offspring to hypertensive mothers have greater LV mass (male: 88±19 vs 139±62 mg P < .01; female: 74±21 vs 104±27 P < .05) and wall thickness (male: 0.70±0.03 vs 0.95±0.22 mm P < .05; female: 0.63±0.15 vs 0.91±0.17 mm P < .05) compared to control offspring. However, in females only, these changes were added by an important LV chamber dilation (3.3±0.3 vs 3.9±0.4 mm P < .05) and reduced fraction of shortening (48±9 vs 33±4 % P < .01), indicating systolic ventricular dysfunction only in female offspring in comparison to controls. Our findings demonstrate for the first time, the feasibility of using fetal and postnatal echocardiography to assess the programming of cardiomyopathy in mice exposed to hypertensive pregnancies. Further, we have described that the transgenic model of maternal hypertension and preeclampsia can induce significant fetal heart remodeling changes that can persist into adulthood in offspring, and in females only, into an accelerated programming of cardiomyopathy.

Fatty Acid Oxidation Promotes Cardiomyocyte Proliferation Rate but Does Not Change Cardiomyocyte Number in Infant Mice.

Cardiomyocyte proliferation accounts for the increase of cardiac muscle during fetal mammalian heart development. Shortly after birth, cardiomyocyte transits from hyperplasia to hypertrophic growth. Here, we have investigated the role of fatty acid β-oxidation in cardiomyocyte proliferation and hypertrophic growth during early postnatal life in mice. A transient wave of increased cell cycle activity of cardiomyocyte was observed between postnatal day 3 and 5, that proceeded as cardiomyocyte hypertrophic growth and maturation. Assessment of cardiomyocyte metabolism in neonatal mouse heart revealed a myocardial metabolic shift from glycolysis to fatty acid β-oxidation that coincided with the burst of cardiomyocyte cell cycle reactivation and hypertrophic growth. Inhibition of fatty acid β-oxidation metabolism in infant mouse heart delayed cardiomyocyte cell cycle exit, hypertrophic growth and maturation. By contrast, pharmacologic and genetic activation of PPARα, a major regulator of cardiac fatty acid metabolism, induced fatty acid β-oxidation and initially promoted cardiomyocyte proliferation rate in infant mice. As the cell cycle proceeded, activation of PPARα-mediated fatty acid β-oxidation promoted cardiomyocytes hypertrophic growth and maturation, which led to cell cycle exit. As a consequence, activation of PPARα-mediated fatty acid β-oxidation did not alter the total number of cardiomyocytes in infant mice. These findings indicate a unique role of fatty acid β-oxidation in regulating cardiomyocyte proliferation and hypertrophic growth in infant mice.

Abstract 16913: Maternal Obesity Impaired Mitochondrial Function of Term Fetal Heart in Sheep

Introduction: Studies in human and animals suggest that maternal obesity (MO) negatively impacts fetal heart development and cardiac function. Epidemiological studies indicate MO could result in increased incidences of cardiovascular diseases in the offspring. However, the underlying mechanisms are still not well elucidated. Our group has developed and characterized a diet-based sheep model of MO beginning before pregnancy as is common in humans to study the effect of MO on fetal heart function. Previously, we have observed compromised contractility and intracellular calcium in MO fetal cardiomyocytes. Here, we look into the mitochondrial function of the term fetal myocardium. Hypothesis: MO impairs fetal heart mitochondrial function and ATP synthesis. Methods: From 60 days before and through pregnancy, ewes were fed either 100% of National Research Council (NRC) recommendations (control, n=6) or 150% of NRC’s recommendations (MO, n=7). At 135-day gestation (Term 150 days), the fetal heart was quickly removed under general anesthesia, and cardiomyocytes were isolated and mitochondria were prepared. Mitochondrial biogenesis was measured by using Seahorse extracellular flux analyzer (XF96) on isolated cardiomyocytes and mitochondrial oxidative phosphorylation complex activity were measured with Abcam assay kits. Analysis by Student’s t-test: *p &lt; 0.05. Results: The Seahorse mitochondrial biogenesis data suggested that mitochondrial maximal and spare respiration rate were significantly reduced in MO fetal cardiomyocytes. More importantly, MO suppressed mitochondrial ATP production in MO fetal cardiomyocytes. The mitochondrial oxidative phosphorylation was downregulated in MO fetal myocardium. We found that complex I and IV enzyme activity was decreased in MO group. The activity of complex V, ATP synthase subunits, was reduced by 43% in MO fetal heart mitochondria. Conclusions: Our results suggest that MO induces stress uterus environment to fetal heart which impairs the mitochondrial function and ATP synthesis, which could be a possible mechanism of maternal obesity-induced cardiac contractile dysfunction.

Non-invasive recordings of fetal electrocardiogram during pregnancy using electric potential sensors

In this letter, we report the early detection of fetal cardiac electrical activity recorded from the maternal abdomen non-invasively. We developed a portable and non-invasive, prototype based on electric potential sensing technology to monitor both: the mother and fetal heart activity during pregnancy. In this proof of principle demonstration, we show the suitability of our technology to monitor the fetal heart development starting at week twenty, when the fetus heart is approximately one-tenth the size of an adult’s heart. The study was conducted for ten weeks to demonstrate how the maturation of the fetus leads to a change on the heart rate dynamics as it approaches birth. Importantly, electrocardiogram information is presented without any post processing given that our device eliminates the requirement of signal conditioning algorithms such as having to un-mix both, the maternal and fetal cardiac waveforms. The provided ECG trace allows extracting the heart rate and other heart activity parameters useful for further diagnostics. Finally, our device does not require any gels to be applied so movement induced potential is eliminated. This technology has the potential to be used for determining possible heart related congenital disorders during pregnancy.

Biobank-driven genomic discovery yields new insight into atrial fibrillation biology.

To identify genetic variation underlying atrial fibrillation, the most common cardiac arrhythmia, we performed a genome-wide association study of >1,000,000 people, including 60,620 atrial fibrillation cases and 970,216 controls. We identified 142 independent risk variants at 111 loci and prioritized 151 functional candidate genes likely to be involved in atrial fibrillation. Many of the identified risk variants fall near genes where more deleterious mutations have been reported to cause serious heart defects in humans (GATA4, MYH6, NKX2-5, PITX2, TBX5)1, or near genes important for striated muscle function and integrity (for example, CFL2, MYH7, PKP2, RBM20, SGCG, SSPN). Pathway and functional enrichment analyses also suggested that many of the putative atrial fibrillation genes act via cardiac structural remodeling, potentially in the form of an 'atrial cardiomyopathy'2, either during fetal heart development or as a response to stress in the adult heart.

VEGF-B electrotransfer mediated gene therapy induces cardiomyogenesis in a rat model of cardiac ischemia

Atherosclerosis induced myocardial infarction (MI) continues to be a major public health concern. Regenerative therapies that restore cardiac muscle cells are largely absent. The rate of cardiomyogenesis in adults is insufficient to compensate for MI damage. In this study, we explored the capacity of a gene therapy approach to promote cardiomyogenesis. We hypothesized that VEGF-B, critical during fetal heart development, could promote cardiomyogenesis in adult ischemic hearts. Gene electrotransfer (GET), a physical method of in vivo gene delivery, was adapted to the rat model of MI. Favorable pulsing parameters were then used for delivery of pVEGF-B and compared to a sham control in terms of infarct size, cardiomyocyte proliferation and presence of new cardiomyocytes. Ki67 immunoreactivity was used for proliferation analysis. Newly synthetized DNA was labeled with BrdU to identify new cells post-infarction. Cardiac troponin co-localization indicated proliferating and new cardiomyocytes histologically. Eight weeks post-treatment, GET pVEGF-B treated hearts had significantly smaller infarcts than the sham control group (p < 0.04). Proliferating and new cardiomyocytes were only present in the GET of pVEGF-B group, and absent in the controls. In summary, GET pVEGF-B promoted cardiomyogenesis post-MI, demonstrating for the first time direct evidence of myocardial regeneration post-infarction.

G-protein receptor kinases 2, 5 and 6 redundantly modulate Smoothened-GATA transcriptional crosstalk in fetal mouse hearts

G-protein receptor kinases (GRKs) regulate adult hearts by modulating inotropic, chronotropic and hypertrophic signaling of 7-transmembrane spanning neurohormone receptors. GRK-mediated desensitization and downregulation of β-adrenergic receptors has been implicated in adult heart failure; GRKs are therefore a promising therapeutic target. However, germ-line (but not cardiomyocyte-specific) GRK2 deletion provoked lethal fetal heart defects, suggesting an unexplained role for GRKs in heart development. Here we undertook to better understand the consequences of GRK deficiency on fetal heart development by creating mice and cultured murine embryonic fibroblasts (MEFs) having floxed GRK2 and GRK5 alleles on the GRK6 null background; simultaneous conditional deletion of these 3 GRK genes was achieved using Nkx2–5 Cre or adenoviral Cre, respectively. Phenotypes were related to GRK-modulated gene expression using whole-transcriptome RNA sequencing, RT-qPCR, and luciferase reporter assays. In cultured MEFs the atypical 7-transmembrane spanning protein and GRK2 substrate Smoothened (Smo) stimulated Gli-mediated transcriptional activity, which was interrupted by deleting GRK2/5/6. Mice with Nkx2–5 Cre mediated GRK2/5/6 ablation died between E15.5 and E16.5, whereas mice expressing any one of these 3 GRKs (i.e. GRK2/5, GRK2/6 or GRK5/6 deleted) were developmentally normal. GRK2/5/6 triple null mice at E14.5 exhibited left and right heart blood intermixing through single atrioventricular valves or large membranous ventricular septal defects. Hedgehog and GATA pathway gene expression promoted by Smo/Gli was suppressed in GRK2/5/6 deficient fetal hearts and MEFs. These data indicate that GRK2, GRK5 and GRK6 redundantly modulate Smo-GATA crosstalk in fetal mouse hearts, orchestrating transcriptional pathways previously linked to clinical and experimental atrioventricular canal defects. GRK modulation of Smo reflects convergence of conventional neurohormonal signaling and transcriptional regulation pathways, comprising an unanticipated mechanism for spatiotemporal orchestration of developmental gene expression in the heart.

Near to One's Heart: The Intimate Relationship Between the Placenta and Fetal Heart.

The development of the fetal heart is exquisitely controlled by a multitude of factors, ranging from humoral to mechanical forces. The gatekeeper regulating many of these factors is the placenta, an external fetal organ. As such, resistance within the placental vascular bed has a direct influence on the fetal circulation and therefore, the developing heart. In addition, the placenta serves as the interface between the mother and fetus, controlling substrate exchange and release of hormones into both circulations. The intricate relationship between the placenta and fetal heart is appreciated in instances of clinical placental pathology. Abnormal umbilical cord insertion is associated with congenital heart defects. Likewise, twin-to-twin transfusion syndrome, where monochorionic twins have unequal sharing of their placenta due to inter-twin vascular anastomoses, can result in cardiac remodeling and dysfunction in both fetuses. Moreover, epidemiological studies have suggested a link between placental phenotypic traits and increased risk of cardiovascular disease in adult life. To date, the mechanistic basis of the relationships between the placenta, fetal heart development and later risk of cardiac dysfunction have not been fully elucidated. However, studies using environmental exposures and gene manipulations in experimental animals are providing insights into the pathways involved. Likewise, surgical instrumentation of the maternal and fetal circulations in large animal species has enabled the manipulation of specific humoral and mechanical factors to investigate their roles in fetal cardiac development. This review will focus on such studies and what is known to date about the link between the placenta and heart development.

Genome-wide Study of Atrial Fibrillation Identifies Seven Risk Loci and Highlights Biological Pathways and Regulatory Elements Involved in Cardiac Development

Atrial fibrillation (AF) is a common cardiac arrhythmia and a major risk factor for stroke, heart failure, and premature death. The pathogenesis of AF remains poorly understood, which contributes to the current lack of highly effective treatments. To understand the genetic variation and biology underlying AF, we undertook a genome-wide association study (GWAS) of 6,337 AF individuals and 61,607 AF-free individuals from Norway, including replication in an additional 30,679 AF individuals and 278,895 AF-free individuals. Through genotyping and dense imputation mapping from whole-genome sequencing, we tested almost nine million genetic variants across the genome and identified seven risk loci, including two novel loci. One novel locus (lead single-nucleotide variant [SNV] rs12614435; p = 6.76× 10-18) comprised intronic and several highly correlated missense variants situated in the I-, A-, and M-bands of titin, which is the largest protein in humans and responsible for the passive elasticity of heart and skeletal muscle. The other novel locus (lead SNV rs56202902; p=1.54× 10-11) covered a large, gene-dense chromosome 1 region that has previously been linked to cardiac conduction. Pathway and functional enrichment analyses suggested that many AF-associated genetic variants act through a mechanism of impaired muscle cell differentiation and tissue formation during fetal heart development.

Identification of intronic-splice site mutations in GATA4 gene in Indian patients with congenital heart disease

Congenital Heart Disease (CHD) is the most common birth defect among congenital anomalies that arise before birth. GATA4 transcription factor plays an important role in foetal heart development. Mutational analysis of GATA4 gene in CHD patients revealed five known heterozygous mutations (p.T355S, p.S377G, p.V380M, p.P394T and p.D425N) identified in exons 5 and 6 regions and fifteen intronic variants in the non-coding regions (g.76885T>C/Y,g.76937G>S, g.78343G>R, g.83073T>Y, g.83271C>A/M, g.83318G>K, g.83415G>R, g.83502A>C/M, g.84991G>R, g.85294C>Y, g.85342C>T/Y, g.86268A>R, g.87409G>A/R, g.87725T>Y, g.87813A>T/W). In silico analysis of these intronic variants identified two potential branch point mutations (g.83271C>A/M, g.86268A>R) and predicted effects of these on intronic splice sites as enhancer and silencer motifs. This study attempts to correlate the pattern of intronic variants of GATA4 gene which might provide new insights to unravel the possible molecular etiology of CHD.

Prenatal Exposure to a Maternal High-Fat Diet Affects Histone Modification of Cardiometabolic Genes in Newborn Rats.

Infants born to women with diabetes or obesity are exposed to excess circulating fuels during fetal heart development and are at higher risk of cardiac diseases. We have previously shown that late-gestation diabetes, especially in conjunction with a maternal high-fat (HF) diet, impairs cardiac functions in rat-offspring. This study investigated changes in genome-wide histone modifications in newborn hearts from rat-pups exposed to maternal diabetes and HF-diet. Chromatin-immunoprecipitation-sequencing revealed a differential peak distribution on gene promoters in exposed pups with respect to acetylation of lysines 9 and 14 and to trimethylation of lysines 4 and 27 in histone H3 (all, false discovery rate, FDR < 0.1). In the HF-diet exposed offspring, 54% of the annotated genes showed the gene-activating mark trimethylated lysine 4. Many of these genes (1) are associated with the “metabolic process” in general and particularly with “positive regulation of cholesterol biosynthesis” (FDR = 0.03); (2) overlap with 455 quantitative trait loci for blood pressure, body weight, serum cholesterol (all, FDR < 0.1); and (3) are linked to cardiac disease susceptibility/progression, based on disease ontology analyses and scientific literature. These results indicate that maternal HF-diet changes the cardiac histone signature in offspring suggesting a fuel-mediated epigenetic reprogramming of cardiac tissue in utero.

Association Between Preeclampsia and Congenital Heart Defects

(JAMA. 2015;314(15):1588–1598) Congenital heart defects are the most common anomaly in infants and are a major cause of infant morbidity and mortality. The origins of congenital heart defects, therefore, need to be better studied in order to improve prevention and earlier detection. Recent studies have tried to identify biomarkers for congenital heart defects as well as preeclampsia. Biomarker findings associated with heart defects include imbalances in proangiogenic signaling proteins, such as vascular endothelial growth factor and placental growth factor, and antiangiogenic proteins, such as soluble endoglin and fms-like tyrosine kinase 1. Imbalances in these same biomarkers have been found with preeclampsia, where there is an excess of soluble endoglin and fms-like tyrosine kinase 1 relative to placental growth factor and vascular endothelial growth factor. Angiogenic mechanisms may be part of a shared pathologic pathway for preeclampsia and congenital heart defects. Studies have shown that the pathologic changes associated with preeclampsia begin early in pregnancy, around the time that fetal heart development is occurring. This current study tried to determine the relationship between preeclampsia and the prevalence of congenital heart defects in infants whose mothers had the disorder.

The Risk of Congenital Heart Anomalies Following Prenatal Exposure to Serotonin Reuptake Inhibitors—Is Pharmacogenetics the Key?

Serotonin reuptake inhibitors (SRIs) are often prescribed during pregnancy. Previous studies that found an increased risk of congenital anomalies, particularly congenital heart anomalies (CHA), with SRI use during pregnancy have created concern among pregnant women and healthcare professionals about the safety of these drugs. However, subsequent studies have reported conflicting results on the association between CHA and SRI use during pregnancy. These discrepancies in the risk estimates can potentially be explained by genetic differences among exposed individuals. In this review, we explore the potential pharmacogenetic predictors involved in the pharmacokinetics and mechanism of action of SRIs, and their relation to the risk of CHA. In general, the risk is dependent on the maternal concentration of SRIs and the foetal serotonin level/effect, which can be modulated by the alteration in the expression and/or function of the metabolic enzymes, transporter proteins and serotonin receptors involved in the serotonin signalling of the foetal heart development. Pharmacogenetics might be the key to understanding why some children exposed to SRIs develop a congenital heart anomaly and others do not.

A novel LabVIEW-based multi-channel non-invasive abdominal maternal-fetal electrocardiogram signal generator

This paper describes the design, construction, and testing of a multi-channel fetal electrocardiogram (fECG) signal generator based on LabVIEW. Special attention is paid to the fetal heart development in relation to the fetus’ anatomy, physiology, and pathology. The non-invasive signal generator enables many parameters to be set, including fetal heart rate (FHR), maternal heart rate (MHR), gestational age (GA), fECG interferences (biological and technical artifacts), as well as other fECG signal characteristics. Furthermore, based on the change in the FHR and in the T wave-to-QRS complex ratio (T/QRS), the generator enables manifestations of hypoxic states (hypoxemia, hypoxia, and asphyxia) to be monitored while complying with clinical recommendations for classifications in cardiotocography (CTG) and fECG ST segment analysis (STAN). The generator can also produce synthetic signals with defined properties for 6 input leads (4 abdominal and 2 thoracic). Such signals are well suited to the testing of new and existing methods of fECG processing and are effective in suppressing maternal ECG while non-invasively monitoring abdominal fECG. They may also contribute to the development of a new diagnostic method, which may be referred to as non-invasive trans-abdominal CTG + STAN. The functional prototype is based on virtual instrumentation using the LabVIEW developmental environment and its associated data acquisition measurement cards (DAQmx). The generator also makes it possible to create synthetic signals and measure actual fetal and maternal ECGs by means of bioelectrodes.

Canine fetal echocardiography: correlations for the analysis of cardiac dimensions.

The aim of this study was to develop regression models for correlation of canine fetal heart development with body size to characterize normal development or suggest cardiac anomalies. Twenty clinically healthy pregnant bitches, either brachycephalic and non-brachycephalic, were examined ultrasonographically. Transabdominal fetal echocardiography was conducted every 4 days from the beginning of cardiac chambers differentiation until parturition. Ten cardiac parameters were measured: length, width and diameter of the heart; heart area; left and right ventricular dimensions; left and right atrial dimensions; and aortic and pulmonary artery diameter. Femoral length, biparietal diameter and abdominal cross-sectional area were also recorded. Regression equations were developed for each parameter of fetal body size, and linear and logarithmic models were compared. The model with the highest correlation coefficient was chosen to produce equations to calculate relative dimensions based on the correlations. Only the left-ventricular chamber differed between the two racial groups. Biparietal diameter was the independent parameter that produced the highest correlation coefficient for the most fetal cardiac dimensions, although good correlations were also observed using femoral length and abdominal cross-sectional area. Heart width and heart diameter were used as surrogates of cardiac development, as these measurements showed the best statistical correlation. Quantitative evaluation of fetal cardiac structures can be used to monitor normal and abnormal cardiac development.

Possible Common Aetiology behind Maternal Preeclampsia and Congenital Heart Defects in the Child: a Cardiovascular Diseases in Norway Project Study.

The aetiology of congenital heart defects (CHD) is mostly unknown, but maternal factors may modify the infant risk of CHD. We investigated the association between maternal preeclampsia and offspring risk of severe CHD in a nation-wide cohort study. Information on all births registered in the Medical Birth Registry of Norway, 1994-2009, was completed with information on CHD diagnoses from national health registries and the Cardiovascular Diseases in Norway Project (CVDNOR). Among 914 703 singleton births without chromosomal abnormalities, 32 864 (3.6%) were born after a pregnancy with preeclampsia. The preeclampsia was diagnosed before the 34th week of pregnancy (early-onset preeclampsia) in 2618 (8.0% of preeclamptic pregnancies). CHDs were diagnosed in 10 691 infants; of these, 2473 had severe CHD. The risk of severe CHD was compared between births with and without maternal preeclampsia and estimated with binomial log-linear regression. When adjusting for year of birth, maternal age, parity, and pregestational diabetes, the risk ratio (RR) for severe CHD in offspring of mothers with any preeclampsia was 1.3 [95% confidence interval (CI) 1.1, 1.5], and in pregnancies with early-onset preeclampsia, the RR was 2.8 (95% CI 1.8, 4.4). The association between early-onset preeclampsia and specific types of severe CHD was stronger for atrioventricular septal defects (AVSD), with adjusted RR 13.5 (95% CI 6.8, 26.8). Early-onset preeclampsia was strongly associated with infant risk of severe CHD, specifically; the risk of AVSD was 15-fold higher if the mother was diagnosed with early-onset preeclampsia, suggesting common aetiological factors for early-onset preeclampsia and erroneous fetal heart development.

The Impact of Oral Intake of Dydrogesterone on Fetal Heart Development During Early Pregnancy.

Congenital heart disease is the most frequent form of congenital anomaly in newborn infants and accounts for more than a quarter of all serious congenital afflictions worldwide. A genetic etiology is identified in <20 % of cases of congenital heart defects, and in most cases the etiology remains a mystery. In the context of the health burden caused by congenital heart disease, the contribution of non-inherited risk factors is important especially if it turns out to be caused by a drug which can be avoided during pregnancy. We sought to determine whether maternal dydrogesterone treatment in early pregnancy is associated with congenital heart disease in the infant. We conducted a retrospective case-control study of birth defects and associated risk factors. Data were obtained and compared between 202 children born with congenital heart disease and a control group consisting of 200 children. All children were born in the period of 2010-2013. Dydrogesterone exposure was defined as any reported use during the first trimester of pregnancy. Exclusion criteria included stillbirths, children with chromosomal abnormalities and infants of mothers with chronic medical illnesses, e.g., diabetes. Binary logistic regression analyses were used to analyze the data and attempt to identify a causal relationship between drug exposure and congenital heart disease. Mothers of children born with congenital heart disease received more dydrogesterone during first trimester of pregnancy than mothers of children in the control group [adjusted odds ratio 2.71; (95 % CI 1.54-4.24); P = 0.001]. We identified a positive association between dydrogesterone usage during early pregnancy and congenital heart disease in the offspring. Nevertheless, further studies are needed to confirm these results.

Differential Expression of Wnt‐pathway in Late Fetal Ovine Heart and Lung Development

Wnt signalling pathways critical to early cardiogenesis have not been extensively studied in sheep. The activity of Wnt signalling during the rapid heart growth occurring between late‐fetal and early newborn development is not known but may be important given that a right ventricular (RV) functional dominance occurs in utero, but a left ventricular (LV) dominance after birth. Thus our aims were to measure cardiopulmonary changes in 7 key proteins (Wnt3a, Wnt5a, Dvl‐1, phospho‐GSK3β, cdc42, ROCK2 and TCF7L2) and genes (Wnt4 and Wnt7b) in the Wnt signalling pathway in fetal and neonatal sheep. Lung, ventricular and atrial samples from pre‐term (age=128‐129 days; term=147 days), near‐term fetal (age=139‐141 days), and neonatal lambs (age= 5‐7 days post birth) were processed for western immunoblots and qRT‐PCR assays. Four main developmental patterns were evident. In the first pattern, the relative ventricular and atrial expression of Wnt3a, Dvl‐1, phospho‐GSK3β increased during fetal development (P&lt;0.05), but decreased after birth (P&lt;0.05). In the second pattern, fetal and newborn Wnt5a and ROCK2 expression was relatively constant, but with RV expression 2‐3 fold higher (P&lt;0.025 – P&lt;0.001). cdc42 expression decreased in both the ventricular and atrial samples. TCF7L2 expression decreased progressively in both ventricles from preterm to neonatal stages, but increased in the atria. Gene expression of Wnt4 and Wnt7b were greater in atrial samples than ventricular samples. Wnt3a, cdc42 and ROCK2 expression decreased in the lungs post birth but increased for Wnt5a and Dvl‐1. These data show that distinct patterns in Wnt signalling occur during ovine fetal growth, with evidence of differential expression between ventricles and atria.