Modulation of cAMP/cGMP signaling as prevention of congenital heart defects in Pde2A deficient embryos: a matter of oxidative stress

Phosphodiesterase 2A (Pde2A) is a dual-specific PDE that breaks down both cAMP and cGMP cyclic nucleotides. We recently highlighted a direct relationship between Pde2A impairment, a consequent increase of cAMP, and the appearance of mouse congenital heart defects (CHDs). Here we aimed to characterize the pathways involved in the development of CHDs and in their prevention by pharmacological approaches targeting cAMP and cGMP signaling. Transcriptome analysis revealed a modulation of more than 500 genes affecting biological processes involved in the immune system, cardiomyocyte development and contractility, angiogenesis, transcription, and oxidative stress in hearts from Pde2A-/- embryos. Metoprolol and H89 pharmacological administration prevented heart dilatation and hypertabeculation in Pde2A-/- embryos. Metoprolol was also able to partially impede heart septum defect and oxidative stress at tissue and molecular levels. Amelioration of cardiac defects was also observed by using the antioxidant NAC, indicating oxidative stress as one of the molecular mechanisms underpinning the CHDs. In addition, Sildenafil treatment recovered cardiac defects suggesting the requirement of cAMP/cGMP nucleotides balance for the correct heart development.

Synergistic protective effects of folic acid and resveratrol against fine particulate matter-induced heart malformations in zebrafish embryos

Ambient fine particulate matter (PM2.5) is a major environmental health problem worldwide, and recent studies indicate that maternal PM2.5 exposure is closely associated with congenital heart diseases (CHDs) in offspring. We previously found that supplementation with folic acid (FA) or Resveratrol (RSV) could protect against heart defects in zebrafish embryos exposed to extractable organic matter (EOM) from PM2.5 by targeting aryl hydrocarbon receptor (AHR) signaling and reactive oxygen species (ROS) production respectively. Thus, we hypothesized that FA combined with RSV may have a synergistic protective effect against PM2.5-induced heart defects. To test our hypothesis, we treated zebrafish embryos with EOM in the presence or absence of FA, RSV or a combination of both. We found that RSV and FA showed a clear synergistic protection against EOM-induced heart defects in zebrafish embryos. Further studies showed that FA and RSV suppressed EOM-induced AHR activity and ROS generation respectively. Although only RSV inhibited EOM-induced apoptosis, FA enhanced the inhibitory effect of RSV. Moreover, vitamin C (VC), a typical antioxidant, also exhibits a synergistic inhibitory effect with FA on EOM-induced apoptosis and heart defects. In conclusion, supplementation with FA and RSV have a synergistic protective effect against PM2.5-induced heart defects in zebrafish embryos by targeting AHR activity and ROS production respectively. Our results indicate that, in the presence of antioxidants, FA even at a low concentration level could protect against the high risk of CHDs caused by air pollution.

Maternal Hypertension-Related Genotypes and Congenital Heart Defects

BACKGROUND

Maternal hypertension has been associated with congenital heart defect occurrence in several studies. We assessed whether maternal genotypes associated with this condition were also associated with congenital heart defect occurrence.

METHODS

We used data from the National Birth Defects Prevention Study to identify non-Hispanic white (NHW) and Hispanic women with (cases) and without (controls) a pregnancy in which a select simple, isolated heart defect was present between 1999 and 2011. We genotyped 29 hypertension-related single nucleotide polymorphisms (SNPs). We conducted logistic regression analyses separately by race/ethnicity to assess the relationship between the presence of any congenital heart defect and each SNP and an overall blood pressure genetic risk score (GRS). All analyses were then repeated to assess 4 separate congenital heart defect subtypes.

RESULTS

Four hypertension-related variants were associated with congenital heart defects among NHW women (N = 1,568 with affected pregnancies). For example, 1 intronic variant in ARHGAP2, rs633185, was associated with conotruncal defects (odds ratio [OR]: 1.3, 95% confidence interval [CI]: 1.1-1.6). Additionally, 2 variants were associated with congenital heart defects among Hispanic women (N = 489 with affected pregnancies). The GRS had a significant association with septal defects (OR: 2.1, 95% CI: 1.2-3.5) among NHW women.

CONCLUSIONS

We replicated a previously reported association between rs633185 and conotruncal defects. Although additional hypertension-related SNPs were also associated with congenital heart defects, more work is needed to better understand the relationship between genetic risk for maternal hypertension and congenital heart defects occurrence.

ALDH2 contributes to melatonin-induced protection against APP/PS1 mutation-prompted cardiac anomalies through cGAS-STING-TBK1-mediated regulation of mitophagy

Ample clinical evidence suggests a high incidence of cardiovascular events in Alzheimer's disease (AD), although neither precise etiology nor effective treatment is available. This study was designed to evaluate cardiac function in AD patients and APP/PS1 mutant mice, along with circulating levels of melatonin, mitochondrial aldehyde dehydrogenase (ALDH2) and autophagy. AD patients and APP/PS1 mice displayed cognitive and myocardial deficits, low levels of circulating melatonin, ALDH2 activity, and autophagy, ultrastructural, geometric (cardiac atrophy and interstitial fibrosis) and functional (reduced fractional shortening and cardiomyocyte contraction) anomalies, mitochondrial injury, cytosolic mtDNA buildup, apoptosis, and suppressed autophagy and mitophagy. APP/PS1 mutation downregulated cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING) levels and TBK1 phosphorylation, while promoting Aβ accumulation. Treatment with melatonin overtly ameliorated unfavorable APP/PS1-induced changes in cardiac geometry and function, apoptosis, mitochondrial integrity, cytosolic mtDNA accumulation (using both immunocytochemistry and qPCR), mitophagy, and cGAS-STING-TBK1 signaling, although these benefits were absent in APP/PS1/ALDH2-/- mice. In vitro evidence indicated that melatonin attenuated APP/PS1-induced suppression of mitophagy and cardiomyocyte function, and the effect was negated by the nonselective melatonin receptor blocker luzindole, inhibitors or RNA interference of cGAS, STING, TBK1, and autophagy. Our data collectively established a correlation among cardiac dysfunction, low levels of melatonin, ALDH2 activity, and autophagy in AD patients, with compelling support in APP/PS1 mice, in which melatonin rescued myopathic changes by promoting cGAS-STING-TBK1 signaling and mitophagy via an ALDH2-dependent mechanism.

Protective Effects of Spermidine and Melatonin on Deltamethrin-Induced Cardiotoxicity and Neurotoxicity in Zebrafish

Increased application of the pyrethroid insecticide deltamethrin has adverse effects on the cardiac system and neurobehavior on the non-target organisms, which has raised the public's attention. Because of spermidine and melatonin considered to have cardioprotective and neuroprotective characteristics, zebrafish were utilized as the model organism to explore the protective effects of spermidine and melatonin against deltamethrin-induced toxicity. We tested the neurobehavior of zebrafish larvae through a rest/wake behavior assay, and evaluated the levels of the expression of Scn5lab, gata4, nkx2.5, hcrt, hcrtr, and aanat2 by qRT-PCR. Besides that cmlc2 was evaluated by whole-mount in situ hybridization. Results have shown that compared with control group, 0.025 mg/L deltamethrin could significantly disturb the cardiac development, downregulating the expression of Scn5lab and transcriptional factors gata4 and nkx2.5, disturbing cardiac looping, resulting in defects in cardiac morphology and function. Moreover, deltamethrin could alter the expression levels of rest/wake genes and cause hyperactivity in zebrafish larvae. Besides, compared with deltamethrin group, the exogenous 0.01 mg/L spermidine and 0.232 mg/L melatonin could significantly rescue the adverse effects of deltamethrin on the cardiac system and neurobehavior in zebrafish. This indicated that spermidine and melatonin have neuroprotective and cardioprotective effects against deltamethrin-induced adverse effects in zebrafish.

Research into the intervention effect of folic acid on arsenic-induced heart abnormalities in fetal rats during the periconception period

BACKGROUND

The incidence of CHD is the highest among birth defects and is increasing year to year. CHD seriously harms the health of infants and young children and presents a large economic burden to families and society. The pathogenesis of CHD and preventive measures are the focus of current research. Our research aimed to explore the intervention effect of folic acid on heart abnormalities resulting from sodium arsenic (NaAsO2) exposure during the periconception period.

METHODS

Sixty 35-day-old female SD rats were randomly divided into 5 groups with 12 rats in each group. Group A was the control group. The rats were given distilled water and ordinary chow. The rats in group B were given distilled water containing 75 mg/L NaAsO2 and ordinary chow. The rats in groups C, D, and E were given distilled water containing 75 mg/L NaAsO2 and chow containing 0.53 mg/kg, 5.3 mg/kg, and 10.6 mg/kg folic acid, respectively. The general condition of the embryos and the histopathology of the embryonic hearts were examined. The acetylation levels of histone H3K9 in heart tissues and the expression levels of Mef2C (which is related to heart development) were observed.

RESULTS

The embryo weight and placental weight of groups B-E were significantly lower than those of group A (P < 0.05). The heart malformation rate of the fetal rats in groups B-E was significantly higher than that of the fetal rats in group A (P < 0.05). We found that the level of H3K9 acetylation in fetal rat cardiomyocytes in groups B-E was significantly higher than that in group A (P < 0.05) and that the level of H3K9 acetylation in groups C-E was lower than that in group B (P < 0.05). The mRNA level of Mef2C in fetal rat cardiomyocytes in group B-E was significantly higher than that in group A (P < 0.05), and the mRNA level of Mef2C in groups C-E was significantly lower than that in group B (P < 0.05).

CONCLUSION

Supplementation with folic acid during the periconception period can interfere with the toxic effects of arsenic on the heart. The mechanism may be that lowering the acetylation levels of histone H3K9 in heart tissues leads to decreased expression levels of Mef2C, which may play a protective role in heart development in fetal rats.

Inhibiting MARSs reduces hyperhomocysteinemia-associated neural tube and congenital heart defects

Hyperhomocysteinemia is a common metabolic disorder that imposes major adverse health consequences. Reducing homocysteine levels, however, is not always effective against hyperhomocysteinemia-associated pathologies. Herein, we report the potential roles of methionyl-tRNA synthetase (MARS)-generated homocysteine signals in neural tube defects (NTDs) and congenital heart defects (CHDs). Increased copy numbers of MARS and/or MARS2 were detected in NTD and CHD patients. MARSs sense homocysteine and transmit its signal by inducing protein lysine (N)-homocysteinylation. Here, we identified hundreds of novel N-homocysteinylated proteins. N-homocysteinylation of superoxide dismutases (SOD1/2) provided new mechanistic insights for homocysteine-induced oxidative stress, apoptosis and Wnt signalling deregulation. Elevated MARS expression in developing and proliferating cells sensitizes them to the effects of homocysteine. Targeting MARSs using the homocysteine analogue acetyl homocysteine thioether (AHT) reversed MARS efficacy. AHT lowered NTD and CHD onsets in retinoic acid-induced and hyperhomocysteinemia-induced animal models without affecting homocysteine levels. We provide genetic and biochemical evidence to show that MARSs are previously overlooked genetic determinants and key pathological factors of hyperhomocysteinemia, and suggest that MARS inhibition represents an important medicinal approach for controlling hyperhomocysteinemia-associated diseases.

AHR-mediated oxidative stress contributes to the cardiac developmental toxicity of trichloroethylene in zebrafish embryos

Trichloroethylene (TCE), a widely used chlorinated solvent, is a common environmental pollutant. Current evidence shows that TCE could induce heart defects during embryonic development, but the underlining mechanism(s) remain unclear. Since activation of the aryl hydrocarbon receptor (AHR) could induce oxidative stress, we hypothesized that AHR-mediated oxidative stress may play a role in the cardiac developmental toxicity of TCE. In this study, we found that the reactive oxygen species (ROS) scavenger, N-Acetyl-L-cysteine (NAC), and AHR inhibitors, CH223191 (CH) and StemRegenin 1, significantly counteracted the TCE-induced heart malformations in zebrafish embryos. Moreover, both CH and NAC suppressed TCE-induced ROS and 8-OHdG (8-hydroxy-2' -deoxyguanosine). TCE did not affect ahr2 and cyp1a expression, but increased cyp1b1 expression, which was restored by CH supplementation. CH also attenuated the TCE-induced mRNA expression changes of Nrf2 signalling genes (nrf2b, gstp2, sod2, ho1, nqo1) and cardiac differentiation genes (gata4, hand2, c-fos, sox9b). In addition, the TCE enhanced SOD activity was attenuated by CH. Morpholino knockdown confirmed that AHR mediated the TCE-induced ROS and 8-OHdG generation in the heart of zebrafish embryos. In conclusion, our results suggest that AHR mediates TCE-induced oxidative stress, leading to DNA damage and heart malformations in zebrafish embryos.

Association Between Maternal Folic Acid Supplementation and Congenital Heart Defects in Offspring in Birth Cohorts From Denmark and Norway

Background Evidence linking individual-level maternal folic acid supplementation to offspring risk of congenital heart defects is lacking. We investigated whether folic acid supplementation in early pregnancy reduces offspring risk of heart defects in 2 large birth cohort studies. Methods and Results Women recruited in early pregnancy within the DNBC (Danish National Birth Cohort), 1996-2003, and MoBa (Norwegian Mother and Child Cohort Study), 2000-2009, were followed until delivery. Information on periconceptional intake of folic acid and other supplements was linked with information on heart defects from national registers. Among 197 123 births, we identified 2247 individuals with heart defects (114/10 000). Periconceptional (4 weeks before through 8 weeks after conception) use of folic acid plus other supplements (54.8%), folic acid only (12.2%), and non-folic acid supplements (5.0%) were compared with no supplement use (28.0%); the adjusted relative risks of heart defects were 0.99 (95% CI, 0.80-1.22), 1.08 (95% CI , 0.93-1.25), and 1.07 (95% CI , 0.97-1.19), respectively. For initiation of folic acid in the preconception period weeks -4 to -1 (33.7%) and the postconception periods 0 to 4 weeks (15.5%), 5 to 8 weeks (17.8%), and 9 to 12 weeks (4.6%), compared with no or late folic acid intake (29.1%), relative risks of heart defect were 1.11 (95% CI , 1.00-1.25), 1.09 (95% CI , 0.95-1.25), 0.98 (95% CI , 0.86-1.12), and 0.97 (95% CI , 0.78-1.20), respectively. Relative risks of severe defects, conotruncal defects, and septal defects showed similar results. Conclusions Folic acid was not associated with offspring risk of heart defects, including severe defects, conotruncal defects, or septal defects.

Sapropterin Treatment Prevents Congenital Heart Defects Induced by Pregestational Diabetes Mellitus in Mice

Background Tetrahydrobiopterin is a cofactor of endothelial NO synthase ( eNOS ), which is critical to embryonic heart development. We aimed to study the effects of sapropterin (Kuvan), an orally active synthetic form of tetrahydrobiopterin on eNOS uncoupling and congenital heart defects ( CHD s) induced by pregestational diabetes mellitus in mice. Methods and Results Adult female mice were induced to pregestational diabetes mellitus by streptozotocin and bred with normal male mice to produce offspring. Pregnant mice were treated with sapropterin or vehicle during gestation. CHD s were identified by histological analysis. Cell proliferation, eNOS dimerization, and reactive oxygen species production were assessed in the fetal heart. Pregestational diabetes mellitus results in a spectrum of CHD s in their offspring. Oral treatment with sapropterin in the diabetic dams significantly decreased the incidence of CHD s from 59% to 27%, and major abnormalities, such as atrioventricular septal defect and double-outlet right ventricle, were absent in the sapropterin-treated group. Lineage tracing reveals that pregestational diabetes mellitus results in decreased commitment of second heart field progenitors to the outflow tract, endocardial cushions, and ventricular myocardium of the fetal heart. Notably, decreased cell proliferation and cardiac transcription factor expression induced by maternal diabetes mellitus were normalized with sapropterin treatment. Furthermore, sapropterin administration in the diabetic dams increased eNOS dimerization and lowered reactive oxygen species levels in the fetal heart. Conclusions Sapropterin treatment in the diabetic mothers improves eNOS coupling, increases cell proliferation, and prevents the development of CHD s in the offspring. Thus, sapropterin may have therapeutic potential in preventing CHD s in pregestational diabetes mellitus.

Maternal folic acid supplementation and dietary folate intake and congenital heart defects

Background

It has been reported that folic acid supplementation before and/or during pregnancy could reduce the risk of congenital heart defects (CHDs). However, the results from limited epidemiologic studies have been inconclusive. We investigated the associations between maternal folic acid supplementation, dietary folate intake, and the risk of CHDs.

Methods

A birth cohort study was conducted in 2010–2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. After exclusion of stillbirths and multiple births, a total of 94 births were identified with congenital heart defects, and 9,993 births without any birth defects. Unconditional logistic regression was used to estimate the associations.

Results

Compared to non-users, folic acid supplement users before pregnancy had a reduced risk of overall CHDs (OR: 0.42, 95% CI: 0.21–0.86, P_trend = 0.025) after adjusted for potential confounders. A protective effect was observed for certain subtypes of CHDs (OR: 0.37, 95% CI: 0.16–0.85 for malformation of great arteries; 0.26, 0.10–0.68 for malformation of cardiac septa; 0.34, 0.13–0.93 for Atrial septal defect). A similar protective effect was also seen for multiple CHDs (OR: 0.49, 95% CI: 0.26–0.93, P_trend = 0.004). Compared with the middle quartiles of dietary folate intake, lower dietary folate intake (<149.88 μg/day) during pregnancy were associated with increased risk of overall CHDs (OR: 1.63, 95% CI: 1.01–2.62) and patent ductus arteriosus (OR: 1.85, 95% CI: 1.03–3.32). Women who were non-user folic acid supplement and lower dietary folate intake have almost 2-fold increased CHDs risk in their offspring.

Conclusions

Our study suggested that folic acid supplementation before pregnancy was associated with a reduced risk of CHDs, lower dietary folate intake during pregnancy was associated with increased risk. The observed associations varied by CHD subtypes. A synergistic effect of dietary folate intake and folic acid supplementation was also observed.

NAD Deficiency, Congenital Malformations, and Niacin Supplementation

BACKGROUND

Congenital malformations can be manifested as combinations of phenotypes that co-occur more often than expected by chance. In many such cases, it has proved difficult to identify a genetic cause. We sought the genetic cause of cardiac, vertebral, and renal defects, among others, in unrelated patients.

METHODS

We used genomic sequencing to identify potentially pathogenic gene variants in families in which a person had multiple congenital malformations. We tested the function of the variant by using assays of in vitro enzyme activity and by quantifying metabolites in patient plasma. We engineered mouse models with similar variants using the CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 system.

RESULTS

Variants were identified in two genes that encode enzymes of the kynurenine pathway, 3-hydroxyanthranilic acid 3,4-dioxygenase (HAAO) and kynureninase (KYNU). Three patients carried homozygous variants predicting loss-of-function changes in the HAAO or KYNU proteins (HAAO p.D162*, HAAO p.W186*, or KYNU p.V57Efs*21). Another patient carried heterozygous KYNU variants (p.Y156* and p.F349Kfs*4). The mutant enzymes had greatly reduced activity in vitro. Nicotinamide adenine dinucleotide (NAD) is synthesized de novo from tryptophan through the kynurenine pathway. The patients had reduced levels of circulating NAD. Defects similar to those in the patients developed in the embryos of Haao-null or Kynu-null mice owing to NAD deficiency. In null mice, the prevention of NAD deficiency during gestation averted defects.

CONCLUSIONS

Disruption of NAD synthesis caused a deficiency of NAD and congenital malformations in humans and mice. Niacin supplementation during gestation prevented the malformations in mice. (Funded by the National Health and Medical Research Council of Australia and others.).

Broad Concepts in Management of Systemic Lupus Erythematosus

Systemic lupus erythematosus is a multisystem autoimmune disease with protean manifestation. Although commonly seen in young women, it can affect men as well as elderly patients. Approach to treatment is multidisciplinary, involves defining the extent of organ involvement, and distinguishing between active manifestations and damage. The mainstay of therapy is judicious use of immunosuppressive medications. Long-term follow-up to address morbidity arising from treatment complications, disease damage, and increased cardiovascular risk is essential.

Maternal and infant genetic variants, maternal periconceptional use of selective serotonin reuptake inhibitors, and risk of congenital heart defects in offspring: population based study

Objective To evaluate whether the association between maternal periconceptional use of selective serotonin reuptake inhibitors (SSRIs) and increased risk of congenital heart defects in offspring is modified by maternal or infant genetic variants in folate, homocysteine, or transsulfuration pathways.Design Population based study. DNA from mothers, fathers, and infants was genotyped with an Illumina GoldenGate custom single nucleotide polymorphism panel. A hybrid design based on a log linear model was used to calculate relative risks and Bayesian false discovery probabilities (BFDP) to identify polymorphisms associated with congenital heart defects modified by SSRI use.Data sources Data from the US National Birth Defects Prevention Study on 1180 liveborn infants with congenital heart defects and 1644 controls, born 1997-2008.Main outcome measures Cases included infants with selected congenital heart defects and control infants had no major defects. SSRI use was obtained from telephone interviews with mothers.Results For women who reported taking SSRIs periconceptionally, maternal SHMT1 (rs9909104) GG and AGgenotypes were associated with a 5.9 and 2.4 increased risk of select congenital heart defects in offspring, respectively, versus the AA genotype (BFDP=0.69). Compared with the AA genotype, BHMT (rs492842 and rs542852) GG and AG genotypes were associated with twice the riskof congenital heart defects (BFDP=0.74 and 0.79, respectively). MGST1 (rs2075237) CC and ACgenotypes were associated with an increased risk compared with the GG genotype (8.0 and 2.8, respectively; BFDP=0.79). Single nucleotide polymorphism in infant genes in the folate (MTHFS rs12438477), homocysteine (TRDMT1 rs6602178 and GNMT rs11752813) and transsulfuration (GSTP1 rs7941395 and MGST1 rs7294985) pathways were also associated with an increased risk of congenital heart defects.Conclusions Common maternal or infant genetic variants in folate, homocysteine, or transsulfuration pathways are associated with an increased risk of certain congenital heart defects among children of women taking SSRIs during cardiogenesis.

Management of Pregnancy in Patients With Complex Congenital Heart Disease: A Scientific Statement for Healthcare Professionals From the American Heart Association

Today, most female children born with congenital heart disease will reach childbearing age. For many women with complex congenital heart disease, carrying a pregnancy carries a moderate to high risk for both the mother and her fetus. Many such women, however, do not have access to adult congenital heart disease tertiary centers with experienced reproductive programs. Therefore, it is important that all practitioners who will be managing these women have current information not only on preconception counseling and diagnostic evaluation to determine maternal and fetal risk but also on how to manage them once they are pregnant and when to refer them to a regional center with expertise in pregnancy management.

Transgenerational cardiology: One way to a baby's heart is through the mother

Despite decades of progress, congenital heart disease remains a major cause of mortality and suffering in children and young adults. Prevention would be ideal, but formidable biological and technical hurdles face any intervention that seeks to target the main causes, genetic mutations in the embryo. Other factors, however, significantly modify the total risk in individuals who carry mutations. Investigation of these factors could lead to an alternative approach to prevention. To define the risk modifiers, our group has taken an "experimental epidemiologic" approach via inbred mouse strain crosses. The original intent was to map genes that modify an individual's risk of heart defects caused by an Nkx2-5 mutation. During the analysis of >2000 Nkx2-5(+/-) offspring from one cross we serendipitously discovered a maternal-age associated risk, which also exists in humans. Reciprocal ovarian transplants between young and old mothers indicate that the incidence of heart defects correlates with the age of the mother and not the oocyte, which implicates a maternal pathway as the basis of the risk. The quantitative risk varies between strain backgrounds, so maternal genetic polymorphisms determine the activity of a factor or factors in the pathway. Most strikingly, voluntary exercise by the mother mitigates the risk. Therefore, congenital heart disease can in principle be prevented by targeting a maternal pathway even if the embryo carries a causative mutation. Further mechanistic insight is necessary to develop an intervention that could be implemented on a broad scale, but the physiology of maternal-fetal interactions, aging, and exercise are notoriously complex and undefined. This suggests that an unbiased genetic approach would most efficiently lead to the relevant pathway. A genetic foundation would lay the groundwork for human studies and clinical trials.

Effect of Folic Acid Food Fortification in Canada on Congenital Heart Disease Subtypes

BACKGROUND

Previous studies have yielded inconsistent results for the effects of periconceptional multivitamins containing folic acid and of folic acid food fortification on congenital heart defects (CHDs).

METHODS

We carried out a population-based cohort study (N=5 901 701) of all live births and stillbirths (including late-pregnancy terminations) delivered at ≥20 weeks' gestation in Canada (except Québec and Manitoba) from 1990 to 2011. CHD cases were diagnosed at birth and in infancy (n=72 591). We compared prevalence rates and temporal trends in CHD subtypes before and after 1998 (the year that fortification was mandated). An ecological study based on 22 calendar years, 14 geographic areas, and Poisson regression analysis was used to quantify the effect of folic acid food fortification on nonchromosomal CHD subtypes (n=66 980) after controlling for changes in maternal age, prepregnancy diabetes mellitus, preterm preeclampsia, multiple birth, and termination of pregnancy.

RESULTS

The overall birth prevalence rate of CHDs was 12.3 per 1000 total births. Rates of most CHD subtypes decreased between 1990 and 2011 except for atrial septal defects, which increased significantly. Folic acid food fortification was associated with lower rates of conotruncal defects (adjusted rate ratio [aRR], 0.73, 95% confidence interval [CI], 0.62-0.85), coarctation of the aorta (aRR, 0.77; 95% CI, 0.61-0.96), ventricular septal defects (aRR, 0.85; 95% CI, 0.75-0.96), and atrial septal defects (aRR, 0.82; 95% CI, 0.69-0.95) but not severe nonconotruncal heart defects (aRR, 0.81; 95% CI, 0.65-1.03) and other heart or circulatory system abnormalities (aRR, 0.98; 95% CI, 0.89-1.11).

CONCLUSIONS

The association between food fortification with folic acid and a reduction in the birth prevalence of specific CHDs provides modest evidence for additional benefit from this intervention.

Methylene Blue Partially Rescues Heart Defects in a Drosophila Model of Huntington's Disease

BACKGROUND

Huntington's disease (HD) is a Polyglutamine disease caused by the presence of CAG repeats in the first exon of Huntingtin (Htt), a large protein with multiple functions. In addition to neurodegeneration of specific brain regions, notably the striatum, HD also shows alterations in peripheral tissues, such as the heart, skeletal muscles or peripheral endocrine glands. Mutant Huntingtin (mHtt)-driven mitochondrial impairment may underlie some of the CNS and peripheral tissues dysfunctions, especially in tissues with high energy demand such as the heart.

OBJECTIVE

The aim of this study is to characterize two new inducible Drosophila HD heart models and to assay the therapeutic potential of methylene blue in these HD models.

METHODS

We report the construction of inducible Drosophila HD heart models, expressing two Nter fragments of the protein encompassing either exon 1 or the first 171 amino acids and the characterization of heart phenotypes in vivo.

RESULTS

We show that both mHtt fragments are able to impair fly cardiac function with different characteristics. Additionally, expression of mHtt, which was limited to adulthood only, leads to mild heart impairment, as opposed to a strong and age-dependent phenotype observed when mHtt expression was driven during both developmental and adult stages. We report that treatment with methylene blue (MB), a protective compound in mitochondria-related diseases, partially protects the fly's heart against mHtt-induced toxicity, but does not rescue neuronal or glial phenotypes in other fly models of HD. This may be linked to its low penetration through the fly's blood-brain barrier.

CONCLUSIONS

Our data suggest that improvement of mitochondrial function by MB, or related compounds, could be an efficient therapeutic strategy to prevent cardiac failure in HD patients.

Who Should Be Targeted for the Prevention of Birth Defects? A Latent Class Analysis Based on a Large, Population-Based, Cross-Sectional Study in Shaanxi Province, Western China

Background

The wide range and complex combinations of factors that cause birth defects impede the development of primary prevention strategies targeted at high-risk subpopulations.

Methods

Latent class analysis (LCA) was conducted to identify mutually exclusive profiles of factors associated with birth defects among women between 15 and 49 years of age using data from a large, population-based, cross-sectional study conducted in Shaanxi Province, western China, between August and October, 2013. The odds ratios (ORs) and 95% confidence intervals (CIs) of associated factors and the latent profiles of indicators of birth defects and congenital heart defects were computed using a logistic regression model.

Results

Five discrete subpopulations of participants were identified as follows: No folic acid supplementation in the periconceptional period (reference class, 21.37%); low maternal education level + unhealthy lifestyle (class 2, 39.75%); low maternal education level + unhealthy lifestyle + disease (class 3, 23.71%); unhealthy maternal lifestyle + advanced age (class 4, 4.71%); and multi-risk factor exposure (class 5, 10.45%). Compared with the reference subgroup, the other subgroups consistently had a significantly increased risk of birth defects (ORs and 95% CIs: class 2, 1.75 and 1.21–2.54; class 3, 3.13 and 2.17–4.52; class 4, 5.02 and 3.20–7.88; and class 5, 12.25 and 8.61–17.42, respectively). For congenital heart defects, the ORs and 95% CIs were all higher, and the magnitude of OR differences ranged from 1.59 to 16.15.

Conclusions

A comprehensive intervention strategy targeting maternal exposure to multiple risk factors is expected to show the strongest results in preventing birth defects.

The protective effect of vitamin E against prenatal and early postnatal ethanol treatment-induced heart abnormality in rats: a 3-month follow-up study

Ethanol consumption during pregnancy is associated with fetal heart malformation. However, the underlying mechanism of prenatal ethanol exposure causing heart malfunction is not well known. The current study examined the effect of prenatal and early postnatal ethanol consumption on heart abnormality resulting from oxidative and inflammatory stress. It was also intended to find out whether vitamin E inhibits the abnormality induced by ethanol in rats' heart tissue. Pregnant Wistar rats received ethanol with/without vitamin E from the seventh day of gestation (GD7) throughout lactation. The proliferation in heart muscle cells and coronary smooth muscle cells, protein carbonyl, IL-6, TNF-α, homocysteine levels, also lipid profile in heart and plasma of male pups were measured at the end of lactation (PN 21) and 90 days after birth (PN 90). The results indicated proliferation of heart muscle and coronary smooth muscle cells along with heart structural alteration, protein oxidation, lipid peroxidation, inflammatory reaction, and hyperhomocysteinemia in offspring after 21 and 90 days of birth compared with the controls. Vitamin E treatment significantly decreased cell proliferation and heart structural alteration, compared with the group treated by ethanol alone. Furthermore, it reduced the elevation of protein carbonyl, lipid peroxidation, and increased inflammatory proteins to levels as those of the controls. These findings strongly support the idea that ethanol intake by dams during pregnancy and early postnatal days induces heart abnormality mediated by oxidative stress and inflammatory reactions, and that these effects can be alleviated by using vitamin E as an antioxidant and anti-inflammatory molecule.

N-Acetylcysteine prevents congenital heart defects induced by pregestational diabetes

BACKGROUND

Pregestational diabetes is a major risk factor of congenital heart defects (CHDs). Glutathione is depleted and reactive oxygen species (ROS) production is elevated in diabetes. In the present study, we aimed to examine whether treatment with N-acetylcysteine (NAC), which increases glutathione synthesis and inhibits ROS production, prevents CHDs induced by pregestational diabetes.

METHODS

Female mice were treated with streptozotocin (STZ) to induce pregestational diabetes prior to breeding with normal males to produce offspring. Some diabetic mice were treated with N-acetylcysteine (NAC) in drinking water from E0.5 to the end of gestation or harvesting of the embryos. CHDs were identified by histology. ROS levels, cell proliferation and gene expression in the fetal heart were analyzed.

RESULTS

Our data show that pregestational diabetes resulted in CHDs in 58% of the offspring, including ventricular septal defect (VSD), atrial septal defect (ASD), atrioventricular septal defects (AVSD), transposition of great arteries (TGA), double outlet right ventricle (DORV) and tetralogy of Fallot (TOF). Treatment with NAC in drinking water in pregestational diabetic mice completely eliminated the incidence of AVSD, TGA, TOF and significantly diminished the incidence of ASD and VSD. Furthermore, pregestational diabetes increased ROS, impaired cell proliferation, and altered Gata4, Gata5 and Vegf-a expression in the fetal heart of diabetic offspring, which were all prevented by NAC treatment.

CONCLUSIONS

Treatment with NAC increases GSH levels, decreases ROS levels in the fetal heart and prevents the development of CHDs in the offspring of pregestational diabetes. Our study suggests that NAC may have therapeutic potential in the prevention of CHDs induced by pregestational diabetes.

Folate deficiency and folic acid supplementation: the prevention of neural-tube defects and congenital heart defects

Diet, particularly vitamin deficiency, is associated with the risk of birth defects. The aim of this review paper is to show the characteristics of common and severe neural-tube defects together with congenital heart defects (CHD) as vitamin deficiencies play a role in their origin. The findings of the Hungarian intervention (randomized double-blind and cohort controlled) trials indicated that periconceptional folic acid (FA)-containing multivitamin supplementation prevented the major proportion (about 90%) of neural-tube defects (NTD) as well as a certain proportion (about 40%) of congenital heart defects. Finally the benefits and drawbacks of three main practical applications of folic acid/multivitamin treatment such as (i) dietary intake; (ii) periconceptional supplementation; and (iii) flour fortification are discussed. The conclusion arrived at is indeed confirmation of Benjamin Franklin's statement: "An ounce of prevention is better than a pound of care".

Echocardiographic integrated backscatter for assessing reduction of aortic valve calcifications by R-568 in a rat model of chronic kidney disease

Chronic kidney disease (CKD) and secondary hyper-parathyroidism are associated with calcific aortic valve disease (CAVD). Innovative modalities for imaging CAVD are warranted. Our aim was to use echocardiographic calibrated integrated backscatter (cIB) to quantitatively determine the preventive effect of the calcimimetic R-568 on CAVD in a CKD rat model, and to compare the results with those of micro-computed tomography and histology. Thirty-six male Wistar rats were followed for 7 wk. Rats were divided into four groups with respect to treatment: (1) adenine 0.5% to induce CKD + vehicle; (2) adenine + R-568 (30 mg/kg/d); (3) control, normal diet + vehicle; (4) controls, normal diet + R-568. At week 7, cIB values of the aortic valve were significantly lower in R-568-treated group 2 than in vehicle-treated group 1. This was confirmed by the significantly lower calcified volume observed on micro-computed tomography and the calcified area observed on histology. There were no significant differences in fractional area change and aortic valve area between groups. In conclusion, echocardiographic cIB was able to quantitatively assess a reduction in CAVD by R-568 in a rat model of CKD.

Environmental origins of congenital heart disease: the heart-placenta connection

Although the mammalian embryo is well protected in the uterus, environmental chemicals, drugs, and maternal nutritional imbalances can interfere with regulatory pathways directing placental and embryonic development early in gestation. Embryonic cells are most susceptible to environmental influences during cellular specification and differentiation stages. Because biochemical differentiation precedes morphological outcome often by days, the period of susceptibility to environmental chemicals expectedly precedes visible morphogenic effects. The cellular mechanisms by which drugs and other environmental factors disrupt embryonic development and induce cardiac abnormalities have remained undefined.

Zinc supplementation prevents cardiomyocyte apoptosis and congenital heart defects in embryos of diabetic mice

Oxidative stress induced by maternal diabetes plays an important role in the development of cardiac malformations. Zinc (Zn) supplementation of animals and humans has been shown to ameliorate oxidative stress induced by diabetic cardiomyopathy. However, the role of Zn in the prevention of oxidative stress induced by diabetic cardiac embryopathy remains unknown. We analyzed the preventive role of Zn in diabetic cardiac embryopathy by both in vivo and in vitro studies. In vivo study revealed a significant decrease in lipid peroxidation, superoxide ions, and oxidized glutathione and an increase in reduced glutathione, nitric oxide, and superoxide dismutase in the developing heart at embryonic days (E) 13.5 and 15.5 in the Zn-supplemented diabetic group when compared to the diabetic group. In addition, significantly down-regulated protein and mRNA expression of metallothionein (MT) in the developing heart of embryos from diabetic group was rescued by Zn supplement. Further, the nuclear microscopy results showed that trace elements such as phosphorus, calcium, and Zn levels were significantly increased (P<0.001), whereas the iron level was significantly decreased (P<0.05) in the developing heart of embryos from the Zn-supplemented diabetic group. In vitro study showed a significant increase in cellular apoptosis and the generation of reactive oxygen species (ROS) in H9c2 (rat embryonic cardiomyoblast) cells exposed to high glucose concentrations. Supplementation with Zn significantly decreased apoptosis and reduced the levels of ROS. In summary, oxidative stress induced by maternal diabetes could play a role in the development and progression of cardiac embryopathy, and Zn supplementation could be a potential therapy for diabetic cardiac embryopathy.

Glutathione transferase pi class 2 (GSTp2) protects against the cardiac deformities caused by exposure to PAHs but not PCB-126 in zebrafish embryos

Glutathione transferases (GSTs) are phase II enzymes that detoxify a wide range of toxicants and reactive intermediates. One such class of toxicants is the ubiquitous polycyclic aromatic hydrocarbons (PAHs). Certain PAHs are known to cause developmental cardiac toxicity in fish. Herein, we explored the role of GST pi class 2 (GSTp2) in PAH- and PCB-induced cardiac toxicity in zebrafish (Danio rerio) embryos. We measured expression of GSTp2 in embryos exposed to individual and co-exposures of the PAHs benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), and fluoranthene (FL) as well as 3,3',4,4',5-pentachlorobiphenyl (PCB-126). GSTp2 mRNA expression was induced by exposure to BkF, BaP, PCB-126, and BaP+FL and BkF+FL co-exposure. A splice junction morpholino was then used to knockdown GSTp2 in developing zebrafish. GSTp2 knockdown exacerbated the toxicity caused by co-exposures to BkF+FL and BaP+FL. However, GSTp2 knockdown did not affect PCB-126 toxicity. These results further suggest that pi class GSTs serve a protective function against the synergistic toxicity caused by PAHs in developing zebrafish.

Statins in non-ischaemic cardiomyopathy: an update on our current clinical and pathophysiological understanding

Statins are a cornerstone in reducing cardiovascular events. Studies show that statins are beneficial even in patients with normal or low cholesterol levels, indicating pleiotropic mechanisms of therapeutic benefit apart from their antihyperlipidemic effect. Non-randomised, observational and retrospective studies suggest that statins are associated with better outcomes in patients with heart failure (HF) of both ischaemic and non-ischaemic aetiologies. While cholesterol reduction and plaque stabilisation likely play a role in reducing cardiovascular events in ischaemic HF patients, the mechanisms underlying the benefit in non-ischaemic HF patients is less clear. This review suggests the pleiotropic effects of statin therapy can beneficially alter the pathophysiological mechanisms underlying the clinical benefit observed in non-ischaemic HF patients.

Rescue of developmental defects by blastocyst stem cell injection: towards elucidation of neomorphic corrective pathways

Stem cell-based therapy is an exciting area of high potential for regenerative medicine. To study disease prevention, we inject mouse embryonic stem cells (ESCs) into a variety of mouse blastocysts, most of which harbor mutations. Mice derived from these mutant blastocysts develop human-like diseases, either at developmental stages or in the adult, but blastocyst injection of ESCs prevents disease from occurring. Rather than entirely repopulating the affected organs, with just 20% of chimerism, the ESCs replenish protein levels that are absent in mutant mice, and induce novel or "neomorphic" signals that help circumvent the requirements for the mutations. We also show data indicating that the "neomorphic" mechanisms arise as a result of blastocyst injection of ESCs, regardless of the nature of the host blastocyst (mutant or wild-type). Thus, blastocyst injection of ESCs not only allows the study of disease prevention, but also unveils novel pathways whose activation may aid in the correction of congenital or acquired disease.

[Evaluation of different ultrasonic modalities for prenatal screening congenital heart diseases]

OBJECTIVE

To evaluate the value of four chamber view, outflow tract view and color Doppler echocardiography for detecting the fetal congenital heart defects among high-risk populations. And to discuss the significance of screening congenital heart defects by three methods and select the suitable method for wider applications.

METHODS

The echocardiographic records of all pregnant women performed at our hospital from January 2006 to December 2007 were reviewed retrospectively by screening of clinical epidemiology. All cases received ultrasonic examinations. The abnormal cases with postnatal confirmation by echocardiogram or autopsy were included. The abnormalities detected in each view were analyzed and classified.

RESULTS

A total of 52 fetuses with congenital heart defects were detected by gray scale sonography and color Doppler sonography in 1310 cases. Each specific cardiac defect had its typical finding in these three planes. The sensitivities of three methods were 61.5%, 88.5% and 96.1% respectively.

CONCLUSION

Four chamber view, outflow tract view and color Doppler sonography have played an important role in screening fetal common congenital heart defects. Outflow tract view is easy to operate and it may be recommended as a suitable method.

Failure of intravenous immunoglobulin to prevent congenital heart block: Findings of a multicenter, prospective, observational study

OBJECTIVE

Congenital heart block (CHB) is presumed to be caused by transplacental passage of maternal immunoglobulin against Ro and La ribonucleoproteins. The recurrence rate in subsequent pregnancies following the birth of a child with CHB is approximately 19%. The purpose of this study was to determine whether intravenous immunoglobulin (IVIG) therapy could prevent the development of CHB in the fetuses of high-risk pregnant women.

METHODS

A total of 24 pregnancies in 22 women who had a previous pregnancy in which CHB developed, were over the age of 18 years, were <12 weeks pregnant, and had anti-Ro, anti-La, or both antibodies were monitored in this multicenter, prospective, observational study. Fifteen patients received infusions of IVIG. The 9 pregnancies in the remaining 7 patients served as controls. IVIG was administered at a dose of 400 mg/kg at weeks 12, 15, 18, 21, and 24 of pregnancy. Echocardiograms were performed at least every 3 weeks from week 15 to week 30 of gestation. Electrocardiograms were obtained at birth. The outcome measure was the development of third-degree CHB detected by fetal echocardiogram.

RESULTS

CHB developed in 3 babies among the 15 pregnancies in the treatment group (20%) and in 1 baby among the 9 pregnancies in the control group (11%). CHB was detected at weeks 18, 23, and 26, respectively, in the 3 babies in the treated group and at week 19 in the baby in the control group. Three of the affected pregnancies ended in termination; 2 for reasons related to the fetal disease and 1 for reasons related to both maternal (severe pulmonary hypertension) and fetal disease (at 21 weeks of gestation).

CONCLUSION

IVIG at the dose and frequency used in this study was not effective as prophylactic therapy for CHB in high-risk mothers.

Folate rescues lithium-, homocysteine- and Wnt3A-induced vertebrate cardiac anomalies

Elevated plasma homocysteine (HCy), which results from folate (folic acid, FA) deficiency, and the mood-stabilizing drug lithium (Li) are both linked to the induction of human congenital heart and neural tube defects. We demonstrated previously that acute administration of Li to pregnant mice on embryonic day (E)6.75 induced cardiac valve defects by potentiating Wnt-beta-catenin signaling. We hypothesized that HCy may similarly induce cardiac defects during gastrulation by targeting the Wnt-beta-catenin pathway. Because dietary FA supplementation protects from neural tube defects, we sought to determine whether FA also protects the embryonic heart from Li- or HCy-induced birth defects and whether the protection occurs by impacting Wnt signaling. Maternal elevation of HCy or Li on E6.75 induced defective heart and placental function on E15.5, as identified non-invasively using echocardiography. This functional analysis of HCy-exposed mouse hearts revealed defects in tricuspid and semilunar valves, together with altered myocardial thickness. A smaller embryo and placental size was observed in the treated groups. FA supplementation ameliorates the observed developmental errors in the Li- or HCy-exposed mouse embryos and normalized heart function. Molecular analysis of gene expression within the avian cardiogenic crescent determined that Li, HCy or Wnt3A suppress Wnt-modulated Hex (also known as Hhex) and Islet-1 (also known as Isl1) expression, and that FA protects from the gene misexpression that is induced by all three factors. Furthermore, myoinositol with FA synergistically enhances the protective effect. Although the specific molecular epigenetic control mechanisms remain to be defined, it appears that Li or HCy induction and FA protection of cardiac defects involve intimate control of the canonical Wnt pathway at a crucial time preceding, and during, early heart organogenesis.

Prevalence of severe congenital heart disease after folic acid fortification of grain products: time trend analysis in Quebec, Canada

OBJECTIVE

To investigate whether the 1998 government policy for mandatory fortification of flour and pasta products with folate was followed by a reduction in the prevalence of severe congenital heart defects.

DESIGN

Time trend analysis.

SETTING

Province of Quebec, Canada.

PARTICIPANTS

Infants born in 1990-2005 identified with severe congenital heart defects (tetralogy of Fallot, endocardial cushion defects, univentricular hearts, truncus arteriosus, or transposition complexes) in Quebec administrative databases.

METHODS

Data analysed in two time periods (before and after fortification). Birth prevalence measured annually as infants (live and stillbirths) with severe congenital heart defects per 1000 births in Quebec. Changes in the birth prevalence from the period before to the period after fortification were estimated with Poisson regression.

RESULTS

Among the 1, 324,440 births in Quebec in 1990-2005 there were 2083 infants born with severe congenital heart defects, corresponding to an average birth prevalence of 1.57/1000 births. Time trend analysis showed no change in the birth prevalence of severe birth defects in the nine years before fortification (rate ratio 1.01, 95% confidence interval 0.99 to 1.03), while in the seven years after fortification there was a significant 6% decrease per year (0.94, 0.90 to 0.97).

CONCLUSIONS

Public health measures to increase folic acid intake were followed by a decrease in the birth prevalence of severe congenital heart defects. These findings support the hypothesis that folic acid has a preventive effect on heart defects.

[Evaluation of the prenatal screening mode for fetal congenital heart diseases by ultrasound]

OBJECTIVE

To assess prenatal heart disease screening program by ultrasound.

METHODS

A total of 11,544 second-trimester screening scans were performed before 24 weeks' gestation on 11,410 women between February 2004 and May 2007 in Obstetrics and Gynecology Hospital of Fudan University. Fetal heart screening was based on four-chamber and outflow tract views (left ventricular outflow + three vessel view). The sensitivity and specificity of different views were evaluated. Follow-up data of newborns was obtained.

RESULTS

(1) Among 11,544 cases,48 cases of congenital heart disease (CHD) were diagnosed in utero. Six cases were false negative, and 2 cases were false positive. The incidence of CHD was 0.47% (54/11 544). (2) Thirty-three CHDs were detected based on the four-chamber view, including 18 ventricular septal defect (9 with conotruncal anomalies), 6 anomalous atrioventricle valve, 9 disproportion of left/right ventricle. The sensitivity of the four-chamber view alone was 61.11% (33/54), and the specificity was 99.98% (11 488/11 490). Fifteen CHDs were detected based on the left ventricular outflow and three vessel views, including 1 pulmonary atresia, 3 pulmonary valve stenosis, 2 transposition of the great arteries (TGA), 1 pulmonary stenosis with TGA, 6 tetralogy of Fallot, and 2 pulmonary stenosis. The sensitivity of the combination of the four-chamber and outflow tract views was 88.89% (48/54), and the specificity was 99.98% (11 488/11 490). (3) Of 48 CHDs, 11 cases were accompanied by other malformations. Eleven cases were performed amniocentesis, among whom 5 cases were trisomy 21.

CONCLUSION

The screening program based on four-chamber and outflow tract views shows good sensitivity and excellent specificity. Our prenatal heart screening program is clinically feasible.

Retinoic acid and the heart

Retinoic acid (RA), the active derivative of vitamin A, by acting through retinoid receptors, is involved in signal transduction pathways regulating embryonic development, tissue homeostasis, and cellular differentiation and proliferation. RA is important for the development of the heart. The requirement of RA during early cardiovascular morphogenesis has been studied in targeted gene deletion of retinoic acid receptors and in the vitamin A-deficient avian embryo. The teratogenic effects of high doses of RA on cardiovascular morphogenesis have also been demonstrated in different animal models. Specific cardiovascular targets of retinoid action include effects on the specification of cardiovascular tissues during early development, anteroposterior patterning of the early heart, left/right decisions and cardiac situs, endocardial cushion formation, and in particular, the neural crest. In the postdevelopment period, RA has antigrowth activity in fully differentiated neonatal cardiomyocytes and cardiac fibroblasts. Recent studies have shown that RA has an important role in the cardiac remodeling process in rats with hypertension and following myocardial infarction. This chapter will focus on the role of RA in regulating cardiomyocyte growth and differentiation during embryonic and the postdevelopment period.

Genetic and lifestyle factors related to the periconception vitamin B12 status and congenital heart defects: a Dutch case-control study

Maternal hyperhomocysteinemia is associated with congenital heart defects (CHDs) in the offspring. A low periconception vitamin B12 status is determined by genetic and lifestyle factors and causes hyperhomocysteinemia. We investigated methionine synthase reductase (MTRR) and transcobalamin II (TC) genes and maternal intake and serum concentrations of vitamin B12 in association with CHD risk. Seventeen months after the index-pregnancy, we studied 230 children with a CHD and 251 non-malformed children and their parents. Data were collected on current and periconception maternal vitamin supplement use and maternal dietary vitamin B12 intake of the month before the study moment. Blood samples were taken for the determination of MTRR A66G and TC C776G genotypes in families and maternal serum vitamin B12 concentrations. Transmission disequilibrium tests and univariate and multivariate analyses were applied. Allele transmissions were not significantly distorted. The MTRR and TC genotypes did not significantly affect CHD risk. Neither polymorphisms in mothers and/or children revealed significant interactions nor in combination with low vitamin B12 intake. Low maternal serum vitamin B12 combined with the maternal or child's MTRR 66 GG genotype resulted in odds ratios of 1.4 (95% confidence interval 0.6-3.5) and 1.3 (0.5-3.4), respectively. The TC 776 GG genotype in mothers and children revealed risk estimates of 2.2 (0.7-7.1) and 1.9 (0.5-7.4), respectively. In conclusion, MTRR 66 GG and TC 776 GG genotypes in mothers and children may contribute to the risk of CHDs, particularly when the maternal vitamin B12 status is low. The future enlargement of our sample size might demonstrate significant associations.

Using reflective nursing practice to improve care of women with congenital heart disease considering pregnancy

This article examines the issue of congenital heart disease (CHD) in women, specifically women who are considering pregnancy. Some of the authors' experiences with women with CHD are described, and a reflective approach to clinical practice is used to gain a greater understanding of the women's perspective. Women with CHD need to balance general lifespan developmental tasks with issues specific to their CHD, such as changes in functional abilities or the possibility of a shortened life expectancy. In women with CHD, physiological, psychological, and family issues need to be considered when they are contemplating pregnancy. As women with CHD move through this debate, nurses may play a key role in assisting them in their decision-making process by exploring issues related to pregnancy and CHD. This exercise in reflective nursing practice allowed us to review the literature, gain new knowledge from our patients, use that knowledge to help other patients, and thoughtfully consider what still needs to be discovered in the care of reproductive-aged women with CHD. The subject of pregnancy contemplation in women with CHD in requires systematic research.

[Study on the correlation of serum folate and red blood cell folate level with birth defects and unexplained recurrent pregnancy loss]

OBJECTIVE

To understand the correlation of lower serum folate, and red blood cell (RBC) folate level with birth defects including unexplained recurrent pregnancy loss, and to evaluate the role of RBC folate level as a suitable marker for folate supplement.

METHODS

Two hundred and ninety-nine non-pregnant women at child-bearing age with a birth defect history were selected as birth defect group. The levels of serum and RBC folate, and serum vitamin B(12) were determined. By comparing with the group of non-pregnant women at child-bearing age without any birth defect history (control group), we evaluated the correlation between lower serum folate, RBC folate level and main kinds of birth defects including unexplained recurrent pregnancy loss. And the levels of serum and RBC folate of birth defect group were also determined and compared before and after oral folate intake (5 mg/d) for one month.

RESULTS

The serum folate level of birth defect group was not different from the control group (17 - 26 vs 14 nmol/L, P > 0.05). The RBC folate level of birth defect group except the urinary defect was significantly lower compared with the control group (233 - 547 vs 689 nmol/L, P < 0.05). After the oral folate intake (5 mg/d), the serum folate level of unexplained recurrent pregnancy loss group and neural tube defects group were significantly increased than before [(22 +/- 9) vs (27 +/- 12) nmol/L, (19 +/- 10) vs (25 +/- 18) nmol/L; P < 0.05]. The RBC folate level of unexplained recurrent pregnancy loss group and congenital heart defect group were significantly increased than before [(374 +/- 275) vs (567 +/- 397) nmol/L, (322 +/- 205) vs (527 +/- 351) nmol/L, P < 0.05].

CONCLUSION

RBC folate level is more closely correlated than serum folate level with the incidence of main birth defect.

Exposure of neural crest cells to elevated glucose leads to congenital heart defects, an effect that can be prevented by N-acetylcysteine

BACKGROUND

Diabetes mellitus during pregnancy increases the risk for congenital heart disease in the offspring. The majority of the cardiovascular malformations occur in the outflow tract and pharyngeal arch arteries, where neural crest cells are essential for normal development. We studied the effects of specific exposure of neural crest cells to elevated glucose on heart development. Antioxidants reduce the damaging effect of glucose on neural crest cells in vitro; therefore, we investigated the effect of supplementing N-acetylcysteine in vivo.

METHODS

Cardiac neural crest of HH 8-12 chicken embryos was directly exposed by a single injection in the neural tube with 30 mM D-glucose (or 30 mM L-glucose as a control). To examine the effect of a reduction in oxidative stress, we added 2 mM N-acetylcysteine to the injected D-glucose.

RESULTS

Exposure of neural crest cells to elevated D-glucose-induced congenital heart malformations in 82% of the embryos. In the embryos injected with L-glucose, only 9% developed a heart malformation. As expected, all malformations were located in the outflow tract and pharyngeal arch arteries. The frequency of heart malformations decreased from 82% to 27% when 2 mM N-acetylcysteine was added to the injected D-glucose.

CONCLUSIONS

These data are the first to confirm that the vulnerability of neural crest cells to elevated glucose induces congenital heart malformations. The fact that N-acetylcysteine limits the teratogenicity of glucose implies that its damaging effect is mediated by an increase of oxidative stress in the neural crest cells.

Noninherited risk factors and congenital cardiovascular defects: current knowledge: a scientific statement from the American Heart Association Council on Cardiovascular Disease in the Young: endorsed by the American Academy of Pediatrics

Prevention of congenital cardiovascular defects has been hampered by a lack of information about modifiable risk factors for abnormalities in cardiac development. Over the past decade, there have been major breakthroughs in the understanding of inherited causes of congenital heart disease, including the identification of specific genetic abnormalities for some types of malformations. Although relatively less information has been available on noninherited modifiable factors that may have an adverse effect on the fetal heart, there is a growing body of epidemiological literature on this topic. This statement summarizes the currently available literature on potential fetal exposures that might alter risk for cardiovascular defects. Information is summarized for periconceptional multivitamin or folic acid intake, which may reduce the risk of cardiac disease in the fetus, and for additional types of potential exposures that may increase the risk, including maternal illnesses, maternal therapeutic and nontherapeutic drug exposures, environmental exposures, and paternal exposures. Information is highlighted regarding definitive risk factors such as maternal rubella; phenylketonuria; pregestational diabetes; exposure to thalidomide, vitamin A cogeners, or retinoids; and indomethacin tocolysis. Caveats regarding interpretation of possible exposure-outcome relationships from case-control studies are given because this type of study has provided most of the available information. Guidelines for prospective parents that could reduce the likelihood that their child will have a major cardiac malformation are given. Issues related to pregnancy monitoring are discussed. Knowledge gaps and future sources of new information on risk factors are described.

Congenital heart defects in Canadian Inuit: is more folic acid making a difference?

INTRODUCTION

Grain fortification of flour with folic acid has successfully reduced neural tube defects (NTDs) by approximately one half of the pre-fortification rate. The knowledge that the use of multivitamins with folic acid has also been shown to reduce some birth defects has prompted interest in determining whether folic acid may also play a role in the prevention of non-neural tube defects. Although NTDs are not more frequent in the Inuit of the Eastern Arctic, septal heart defects, were documented pre-fortification (1989-1994) to be increased 4 fold.

OBJECTIVES

To determine if current efforts of fortification are sufficient and to explore other genetic/ environmental determinants of the increased rate of septal heart defects in the Eastern Arctic.

METHODS

Inuit mothers of children from communities on Baffin Island with and without heart defects were invited to participate in a case control study evaluating nutrient intake, pregnancy exposures, RBC folate, serum cobalamin, homocysteine, and functional polymorphisms for genes important in folate metabolism and uptake.

RESULTS

41 children with isolated heart defects and their mothers with 36 community matched Inuit controls have entered the study to date.

RESULTS

There were no differences in RBC folate (953 Vs 922 nmol/L p = .49), serum cobalamin, and homocysteine, between mothers of cases and controls. The combined average RBC folate for the women ages 18-45 was 947 +/- 32 nmol/L. There was no difference between any documented alcohol (H"30%) and cigarette (H"82%) use in pregnancy. No Inuit women were taking vitamins at conception or at the time of this study. The results of the genetic studies will be reported elsewhere.

CONCLUSIONS

RBC folate (post-fortification) in our sample of women of childbearing years is reassuring. However, it is possible that pre-fortification levels combined with genetic predisposition may have previously influenced the high rate of heart defects. Follow-up study is underway to determine if rates of heart defects have decreased since fortification was commenced. Since folate alone may not be sufficient to reduce non-neural tube defects, culturally appropriate public health efforts need to be initiated to encourage multivitamin use periconceptionally.

Can folic acid protect against congenital heart defects in Down syndrome?

BACKGROUND

Several studies have suggested a protective effect of folic acid (FA) on congenital heart anomalies. Down syndrome (DS) infants are known to have a high frequency of heart anomalies. Not all children with DS suffer from heart anomalies, which raises the question whether maternal factors might affect the risk of these anomalies. Our objectives were to investigate whether first-trimester FA use protects against heart anomalies among DS children.

METHODS

Women with liveborn DS children participating in the Slone Epidemiology Center Birth Defects Study between 1976 and 1997 were included. We performed case-control analyses using DS, with heart anomalies as cases and DS, without heart anomalies as controls. Subanalyses were performed for defects that have been associated with FA in non-DS populations (conotruncal, ventricular septal [VSD]) and for those that are associated with DS (ostium secundum type atrial septal defects [ASD] and endocardial cushion defects [ECD]). Exposure was defined as the use of any FA-containing product for an average of at least 4 days per week during the first 12 weeks of pregnancy, whereas no exposure was defined as no use of FA in these 12 weeks.

RESULTS

Of the 223 cases, 110 (49%) were exposed versus 84 (46%) of the 184 controls. After adjustment for possible confounders, no protective effect of FA was found on heart anomalies overall (OR 0.95, 95% CI: 0.61-1.47) nor separately for conotruncal defects, VSDs, ASDs, or ECDs.

CONCLUSIONS

Our study does not show a protective effect of FA on heart anomalies among infants with DS.

Embryonic stem cells prevent developmental cardiac defects in mice

The potential therapeutic use of embryonic stem cells (ESCs) has gathered the attention of the scientific and medical communities recently. We report that in addition to their unique capacity to populate defective cardiac tissues, ESCs secrete factors that correct gene expression profiles in the defective neighboring cells. Id (inhibitor of DNA binding) gene knockout (KO) mouse embryos die at midgestation because of multiple cardiac defects, but injection of ESCs into preimplantation Id KO embryos prevents these defects and corrects gene expression profiles throughout the heart. ESCs injected into expectant mothers only partially rescue cardiac defects in the Id KO embryos. Two secreted factors are implicated in the rescue process: insulin-like growth factor I accounts for the long-range action of the ESCs, and Wnt5a, a short-range factor, corrects gene expression profiles in the Id KO hearts. Future studies are discussed.

Blocking expression of AHR2 and ARNT1 in zebrafish larvae protects against cardiac toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin

The zebrafish (Danio rerio) has become an attractive vertebrate model for studying developmental processes, and is emerging as a model system for studying the mechanisms by which xenobiotic compounds perturb normal development. Embryos treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) shortly after fertilization exhibit a range of adverse effects on the heart: an early reduction in cardiac myocyte number, followed by a change in heart looping and morphology, with an apparent compaction of the ventricle and overall decrease in heart size. These changes are accompanied by impaired cardiac function including a decrease in cardiac output and eventually irreversible ventricular standstill. The mechanisms involved in mediating effects of TCDD on the heart remain unknown. However, it is widely accepted that aryl hydrocarbon receptor (AHR) activation mediates endpoints of TCDD toxicity in vertebrates. In zebrafish, there are multiple forms of AHR and AHR nuclear translocator protein (ARNT) raising the question about whether different endpoints of TCDD toxicity are mediated by different components of the AHR/ARNT pathway. To address this question we used morpholino oligonucleotide technology to specifically block the expression of zfAHR2, zfARNT1, zfARNT2, and zfCYP1A, and assessed the previously described effects of TCDD on heart morphology, size, and function in the developing morphants. We report that blocking zfAHR2 and zfARNT1 expression provided protection against the TCDD-mediated alteration in heart morphology, reduced cardiac myocyte number, decreased cardiac output and ventricular standstill in zebrafish larvae, while the zfarnt2 and zfcyp1a morpholinos did not block the TCDD-induced cardiac toxicity.