Fetal alcohol syndrome (FAS) in C57BL/6 mice detected through proteomics screening of the amniotic fluid

Murine Models for the Study of Fetal Alcohol Spectrum Disorders: An Overview

Prenatal alcohol exposure is associated to different physical, behavioral, cognitive, and neurological impairments collectively known as fetal alcohol spectrum disorder. The underlying mechanisms of ethanol toxicity are not completely understood. Experimental studies during human pregnancy to identify new diagnostic biomarkers are difficult to carry out beyond genetic or epigenetic analyses in biological matrices. Therefore, animal models are a useful tool to study the teratogenic effects of alcohol on the central nervous system and analyze the benefits of promising therapies. Animal models of alcohol spectrum disorder allow the analysis of key variables such as amount, timing and frequency of ethanol consumption to describe the harmful effects of prenatal alcohol exposure. In this review, we aim to synthetize neurodevelopmental disabilities in rodent fetal alcohol spectrum disorder phenotypes, considering facial dysmorphology and fetal growth restriction. We examine the different neurodevelopmental stages based on the most consistently implicated epigenetic mechanisms, cell types and molecular pathways, and assess the advantages and disadvantages of murine models in the study of fetal alcohol spectrum disorder, the different routes of alcohol administration, and alcohol consumption patterns applied to rodents. Finally, we analyze a wide range of phenotypic features to identify fetal alcohol spectrum disorder phenotypes in murine models, exploring facial dysmorphology, neurodevelopmental deficits, and growth restriction, as well as the methodologies used to evaluate behavioral and anatomical alterations produced by prenatal alcohol exposure in rodents.

Ethanol-Induced Alterations in Placental and Fetal Cerebrocortical Annexin-A4 and Cerebral Cavernous Malformation Protein 3 Are Associated With Reductions in Fetal Cortical VEGF Receptor Binding and Microvascular Density

Jegou et al. (2012) have reported prenatal alcohol exposure (PAE)-induced reductions of angiogenesis-related proteins in mouse placenta. These effects were associated with striking alterations in microvascular development in neonatal cerebral cortex. Here, we employed a rat model of moderate PAE to search for additional proteins whose placental and fetal cortical expression is altered by PAE, along with a subsequent examination of fetal cerebral cortical alterations associated with altered protein expression. Long-Evans rat dams voluntarily consumed either a 0 or 5% ethanol solution 4 h each day throughout gestation. Daily ethanol consumption, which resulted in a mean peak maternal serum ethanol concentration of 60.8 mg/dL, did not affect maternal weight gain, litter size, or placental or fetal body weight. On gestational day 20, rat placental: fetal units were removed by Caesarian section. Placental protein expression, analyzed by 2D-PAGE – tandem mass spectroscopy, identified a total of 1,117 protein spots, 20 of which were significantly altered by PAE. To date, 14 of these PAE-altered proteins have been identified. Western blotting confirmed the alterations of two of these placental proteins, namely, annexin-A4 (ANX-A4) and cerebral cavernous malformation protein 3 (CCM-3). Specifically, PAE elevated ANX-A4 and decreased CCM-3 in placenta. Subsequently, these two proteins were measured in fetal cerebral cortex, along with radiohistochemical studies of VEGF binding and histofluorescence studies of microvascular density in fetal cerebral cortex. PAE elevated ANX-A4 and decreased CCM-3 in fetal cerebral cortex, in a pattern similar to the alterations observed in placenta. Further, both VEGF receptor binding and microvascular density and orientation, measures that are sensitive to reduced CCM-3 expression in developing brain, were significantly reduced in the ventricular zone of fetal cerebral cortex. These results suggest that the expression angiogenesis-related proteins in placenta might serve as a biomarker of ethanol-induced alterations in microvascular development in fetal brain.

Rescue of ethanol-induced FASD-like phenotypes via prenatal co-administration of choline

Maternal consumption of alcohol during pregnancy can generate a multitude of deficits in the offspring. Fetal Alcohol Spectrum Disorders, or FASD, describe a palette of potentially life-long phenotypes that result from exposure to ethanol during human gestation. There is no cure for FASD and cognitive-behavioral therapies typically have low success rates, especially in severe cases. The neocortex, responsible for complex cognitive and behavioral function, is altered by prenatal ethanol exposure (PrEE). Supplementation with choline, an essential nutrient, during the prenatal ethanol insult has been associated with a reduction of negative outcomes associated with PrEE. However, choline's ability to prevent deficits within the developing neocortex, as well as the underlying mechanisms, remain unclear. Here, we exposed pregnant mice to 25% ethanol in addition to a 642 mg/L choline chloride supplement throughout gestation to determine the impact of choline supplementation on neocortical and behavioral development in ethanol-exposed offspring. We found that concurrent choline supplementation prevented gross developmental abnormalities associated with PrEE including reduced body weight, brain weight, and cortical length as well as partially ameliorated PrEE-induced abnormalities in intraneocortical circuitry. Additionally, choline supplementation prevented altered expression of RZRβ and Id2, two genes implicated in postmitotic patterning of neocortex, and global DNA hypomethylation within developing neocortex. Lastly, choline supplementation prevented sensorimotor behavioral dysfunction and partially ameliorated increased anxiety-like behavior observed in PrEE mice, as assessed by the Suok and Ledge tests. Our results suggest that choline supplementation may represent a potent preventative measure for the adverse outcomes associated with PrEE.

The association between prenatal alcohol exposure and protein expression in human placenta

BACKGROUND

The need for earlier recognition of children at risk for neurobehavioral problems associated with prenatal ethanol exposure (PAE) has prompted investigations of biomarkers prognostic for altered fetal development. Here, we examined whether PAE alters the expression of angiogenesis-related proteins and cytokines in human placenta in subjects from an Ethanol, Neurodevelopment, Infant and Child Health prospective cohort.

METHODS

PAE was ascertained by screening questionnaires, Time-line Follow-back interviews and a panel of ethanol biomarkers at two study visits. After delivery, placental tissue samples were collected for protein analysis.

RESULTS

No significant differences in the prevalence of substance use, demographic or medical characteristics were observed between the No PAE and PAE groups. PAE was associated with significant reductions in placental expression of VEGFR2 and annexin-A4, while the levels of VEGFR1 and CCM-3 trended downward. A trend toward higher expression of the cytokines TNF-α and IL-13 was also observed in the PAE group. Receiver operating characteristic analyses of the data demonstrated a moderate-to-high degree of diagnostic accuracy for individual placental proteins. Combinations of proteins substantially increased their ability to differentiate between PAE and No PAE subjects.

CONCLUSIONS

These results establish the feasibility of harvesting placental tissue for protein analyses of PAE in a prospective manner. In addition, given the importance of vascular remodeling in both placenta and developing brain, the role of angiogenic and cytokine proteins in this process warrants further investigation for their utility for predicting alterations in brain development, as well as their mechanistic role in PAE-induced pathology.

Advances in the proteomics of amniotic fluid to detect biomarkers for chromosomal abnormalities and fetomaternal complications during pregnancy

INTRODUCTION

Amniotic fluid (AF) is a dynamic and complex mixture that reflects the physiological condition of developing fetus. In the last decade, proteomic analysis of AF for 16-18 weeks normal pregnancy has been done for the composition and functions of this fluid. Other body fluids such as urine, sweat, tears, etc. are being used for diagnosis of disease, but an insight into protein biomarkers of amniotic fluid can save the fetus and mother from future complications. Areas covered: We have covered the proteomics of amniotic fluid done since 2000, in order to strengthen the establishment of these techniques as a recognized diagnostic tool in the field. After classifying the diseases based on chromosomal aneuploidies, gestational changes, and inflammation caused during pregnancy; we have focused on amniotic fluid to detect various complications during and post pregnancy and its effect on the fetomaternal relationship. Expert comment: The main protein biomarkers responsible for various syndromes, diseases, and complications have been summarized. Major proteins identified for gestational conditions are IGFBP-1, fibrinogen, neutrophil defensins like calgranulins A and C, cathelicidin, APOA1, TRFE, etc. Validation of particular technique and establishing a single standardized biomarker for the diagnosis to avoid any overlapping for different diseases is required. After certain improvements, proteomics approach can be considered for diagnosis of diseases associated with fetal-maternal health.

Review and gap analysis: molecular pathways leading to fetal alcohol spectrum disorders

Alcohol exposure during pregnancy affects the development of the fetus in various ways and may lead to Fetal Alcohol Spectrum Disorders (FASD). FASD is one of the leading preventable forms of neurodevelopmental disorders. In the light of prevention and early intervention, knowledge on how ethanol exposure induces fetal damage is urgently needed. Besides direct ethanol and acetaldehyde toxicity, alcohol increases oxidative stress, and subsequent general effects (e.g., epigenetic imprinting, gene expression, and metabolite levels). The current review provides an overview of the existing knowledge about specific downstream pathways for FASD that affects e.g., the SHH pathway, cholesterol homeostasis, neurotransmitter signaling, and effects on the cytoskeleton. Available human data vary greatly, while animal studies with controlled ethanol exposition are only to a certain limit transferable to humans. The main deficits in knowledge about FASD are the lack of pathophysiological understanding and dose-response relationships, together with the lack of reliable biomarkers for either FASD detection or estimation of susceptibility. In addition to single outcome experiments, omics data should be generated to overcome this problem. Therefore, for future studies we recommend holistic data driven analysis, which allows integrative analyses over multiple levels of genetic variation, transcriptomics and metabolomics data to investigate the whole image of FASD development and to provide insight in potential drug targets for intervention.

Fetal regional brain protein signature in FASD rat model

Fetal alcohol spectrum disorders (FASD) describe neurodevelopmental deficits in children exposed to alcohol in utero. We hypothesized that gestational alcohol significantly alters fetal brain regional protein signature. Pregnant rats were binge-treated with alcohol or pair-fed and nutritionally-controlled. Mass spectrometry identified 1806, 2077, and 1456 quantifiable proteins in the fetal hippocampus, cortex, and cerebellum, respectively. A stronger effect of alcohol exposure on the hippocampal proteome was noted: over 600 hippocampal proteins were significantly (P < .05) altered, including annexin A2, nucleobindin-1, and glypican-4, regulators of cellular growth and developmental morphogenesis. In the cerebellum, cadherin-13, reticulocalbin-2, and ankyrin-2 (axonal growth regulators) were significantly (P < .05) altered; altered cortical proteins were involved in autophagy (endophilin-B1, synaptotagmin-1). Ingenuity analysis identified proteins involved in protein homeostasis, oxidative stress, mitochondrial dysfunction, and mTOR as major pathways in the cortex and hippocampus significantly (P < .05) affected by alcohol. Thus, neurodevelopmental protein changes may directly relate to FASD neuropathology.

Omics in Zebrafish Teratogenesis

The genome revolution represents a complete change on our view of biological systems. The quantitative determination of changes in all major molecular components of the living cells, the "omics" approach, opened whole new fields for all health sciences. Genomics, transcriptomics, proteomics, metabolomics, and others, together with appropriate prediction and modeling tools, will mark the future of developmental toxicity assessment both for wildlife and humans. This is especially true for disciplines, like teratology, which rely on studies in model organisms, as studies at lower levels of organization are difficult to implement. Rodents and frogs have been the favorite models for studying human reproductive and developmental disorders for decades. Recently, the study of the development of zebrafish embryos (ZE) is becoming a major alternative tool to adult animal testing. ZE intrinsic characteristics makes this model a unique system to analyze in vivo developmental alterations that only can be studied applying in toto approaches. Moreover, under actual legislations, ZE is considered as a replacement model (and therefore, excluded from animal welfare regulations) during the first 5 days after fertilization. Here we review the most important components of the zebrafish toolbox available for analyzing early stages of embryotoxic events that could eventually lead to teratogenesis.

Metabolomics and fetal alcohol spectrum disorder

Fetal alcohol spectrum disorder (FASD) is a major public health issue that encompass an array of physical, neurological, and behavioral effects due to alcohol consumption during pregnancy. The classical biomarkers of FASD that are currently used lack sensitivity and specificity, and as such there is an opportunity through the use of novel metabolomics analysis to identify new biomarkers to identify those at risk for FASD, which could more effectively aid in early intervention. The focus of this minireview is to identify current work that is being done in the field of metabolomics in FASD in utero, and to highlight promising metabolites that could act as biomarkers in the future. We will conclude with suggestions for further research, as there is a large gap of knowledge in this particular area of metabolomics.

Differences between NMRI and DBA/2J mice in the development of somites and susceptibility to methylnitrosourea-induced skeleton anomalies

The development of DBA/2J mouse strain embryos is nearly 12 h - or 6 somite pairs - delayed as compared to the outbred NMRI mouse embryos of the same age on gestation days (GD) 8-12. To evaluate inter-strain differences in susceptibility to teratogens, dams were treated with methylnitrosourea (MNU, 5 mg/kg body weight i.p.) on defined gestation days (NMRI: GD 9, 91/2 or 10; DBA/2J: GD 10 or 101/2). Skeletal anomalies produced by MNU on both mouse strains varied with the GD of treatment. The pattern of anomalies produced by MNU on a given GD markedly differed between the two mouse strains, yet they were similar -with a few exceptions- when exposures at equivalent embryonic stages are compared. Findings from this study indicated that strain-dependent differences in the developmental stage of mouse embryos of the same gestational age occur, a possibility that has been often neglected when inter-strain differences in susceptibility to developmental toxicants are interpreted.

Neural tube defects: from a proteomic standpoint

Neural tube defects (NTDs) are congenital birth defects classified according to their resulting morphological characteristics in newborn patients. Current diagnosis of NTDs relies largely on the structural evaluation of fetuses using ultrasound imaging, with biochemical characterization used as secondary screening tools. The multigene etiology of NTDs has been aided by genetic studies, which have discovered panels of genes mutated in these diseases that encode receptors and cytoplasmic signaling molecules with poorly defined functions. Animal models ranging from flies to mice have been used to determine the function of these genes and identify their associated molecular cascades. More emphasis is now being placed on the identification of biochemical markers from clinical samples and model systems based on mass spectrometry, which open novel avenues in the understanding of NTDs at protein, metabolic and molecular levels. This article reviews how the use of proteomics can push forward the identification of novel biomarkers and molecular networks implicated in NTDs, an indispensable step in the improvement of patient management.

High-fat feeding rapidly induces obesity and lipid derangements in C57BL/6N mice

C57BL/6N (B6N) is becoming the standard background for genetic manipulation of the mouse genome. The B6N, whose genome is very closely related to the reference C57BL/6J genome, is versatile in a wide range of phenotyping and experimental settings and large repositories of B6N ES cells have been developed. Here, we present a series of studies showing the baseline characteristics of B6N fed a high-fat diet (HFD) for up to 12 weeks. We show that HFD-fed B6N mice show increased weight gain, fat mass, and hypercholesterolemia compared to control diet-fed mice. In addition, HFD-fed B6N mice display a rapid onset of lipid accumulation in the liver with both macro- and microvacuolation, which became more severe with increasing duration of HFD. Our results suggest that the B6N mouse strain is a versatile background for studying diet-induced metabolic syndrome and may also represent a model for early nonalcoholic fatty liver disease.

Alcohol-induced alterations in maternal uterine endothelial proteome: a quantitative iTRAQ mass spectrometric approach

OBJECTIVE

To quantitate alcohol-induced alterations in the maternal uterine endothelial proteome utilizing iTRAQ-based mass spectrometry.

STUDY DESIGN

Uterine artery endothelial cells from third trimester pregnant ewes were FAC sorted, validated and treated without or with binge-like alcohol. Lysates were trypsin digested, iTRAQ-labeled, and analyzed using nano LC MS/MS.

RESULTS

Alcohol significantly upregulated 14 and downregulated 17 proteins (P<0.05) including those related to cell structure, transcription/translation regulation, histones, Ca(2+)/NO, and redox balance. Gene Ontology and ArrayTrack analyses revealed alterations to protein processing, binding, and nutrient metabolism pathways. Further, alcohol altered proteins previously correlated with fetal alcohol spectrum disorders (FASD) and those that regulate epigenetic, transcriptional, and translational processes.

CONCLUSIONS

Alcohol differentially alters the proteome in the maternal uterine compartment at the level of the endothelium. iTRAQ mass spectrometry provides a robust high throughput platform to comprehend the multi-mechanistic actions of alcohol and develop appropriate biomarkers and ameliorative measures for FASD.

Proteomic analysis of amniotic fluid of pregnant rats with spina bifida aperta

Congenital spina bifida aperta is a common congenital malformation in children and has an incidence of 1‰ to 5‰ in China. However, we currently lack specific biomarkers for screening or prenatal diagnosis and there is no method to entirely cure or prevent such defects. In this study, we used two-dimensional gel electrophoresis (2-DE)/mass spectrometry (MS) to characterize differentially expressed proteins in amniotic-fluid samples (AFSs) of embryonic day (E) 17.5 rat fetuses with spina bifida aperta induced by retinoic acid (RA). We identified five proteins differentially expressed in AFSs of spina bifida aperta, including three upregulated proteins (transferrin, alpha-1 antiproteinase and signal recognition particle receptor, B subunit [SRPRB] 55 kDa), two downregulated proteins (apolipoprotein A IV [APO A4] and Srprb 77 kDa). Specifically, we found 11 alpha-1 fetoprotein (AFP) fragments that were downregulated and 35 AFP fragments that were upregulated in AFSs from embryos with spina bifida aperta. Of the downregulated AFP fragments, 72.7% (8/11) were confined to the AFP N-terminus (amino acids [aas] 25-440) and 77.1% (27/35) of upregulated AFP fragments were confined to the AFP C-terminus (aas 340-596). We also confirmed APO A4 and AFP by immunoblot analysis. This is the first comparative proteomic study of AFSs from rat fetuses with spina bifida aperta. We demonstrate proteomic alterations in the AFS of spina bifida aperta, which may provide new insights in neural tube defects and contribute to the prenatal screening.

2-D DIGE uterine endothelial proteomic profile for maternal chronic binge-like alcohol exposure

Little is known about alcohol effects on the utero-placental compartment during pregnancy. For the first time, we utilized 2-D DIGE quantitative proteomics to evaluate the role of the uterus in Fetal Alcohol Spectrum Disorders (FASD) pathogenesis. Uterine artery endothelial cells were isolated from pregnant ewes, FAC sorted, validated, and maintained in culture. To mimic maternal binge drinking patterns, cells were cultured in the absence or presence of alcohol (300 mg/dl) in a compensating sealed humidified chamber system equilibrated with aqueous alcohol for 3 h on 3 consecutive days for two weeks. CyDye switch combined with 2-D DIGE followed by MALDI-TOF and tandem MS/MS were utilized. Validation was performed using Western immunoblot analysis. Chronic binge-like alcohol significantly (P<0.05) decreased 30 proteins and increased 19 others. Gene-enrichment and functional annotation cluster analysis revealed significant enrichment (P<0.05) in three categories: glutathione S transferase, thioredoxin, and vesicle transport-related. Furthermore, alcohol differentially altered proteins with certain isoforms being downregulated while others were upregulated. In summary, binge alcohol has specific effects on the maternal uterine proteome, especially those related to oxidative stress. The current study also demonstrates a great need to utilize proteomic approaches for diagnostic, mechanistic and therapeutic aspects of FASD.

Fetal alcohol spectrum disorders: an overview

When fetal alcohol syndrome (FAS) was initially described, diagnosis was based upon physical parameters including facial anomalies and growth retardation, with evidence of developmental delay or mental deficiency. Forty years of research has shown that FAS lies towards the extreme end of what are now termed fetal alcohol spectrum disorders (FASD). The most profound effects of prenatal alcohol exposure are on the developing brain and the cognitive and behavioral effects that ensue. Alcohol exposure affects brain development via numerous pathways at all stages from neurogenesis to myelination. For example, the same processes that give rise to the facial characteristics of FAS also cause abnormal brain development. Behaviors as diverse as executive functioning to motor control are affected. This special issue of Neuropsychology Review addresses these changes in brain and behavior highlighting the relationship between the two. A diagnostic goal is to recognize FAS as a disorder of brain rather than one of physical characteristics.

Prenatal exposure to ethanol: a specific effect on the H19 gene in sperm

Alcohol exposure during pregnancy induces a range of disorders in the offspring. Methylation changes in imprinted genes may play a role in the teratogenic effects of alcohol. We evaluated the possible effects of alcohol administration in pregnant mice on the methylation pattern of 5 imprinted genes (H19, Gtl2, Peg1, Snrpn and Peg3) in somatic and sperm cell DNAs of the male offspring. The effects observed were a 3% (p < 0.005) decrease in the number of methylated CpGs of H19 in the F1 offspring sperm, a 4% (p < 0.005) decrease in the number of methylated CpGs of H19 in the F2 offspring brain and a 26% (p < 0.05) decrease in the mean sperm concentration. CpGs 1 and 2 of the H19 CTCF-binding site 2 exhibited significant methylation percentage losses. H19 CTCF-binding sites are important for the regulation of Igf2 gene expression. The hypomethylation of H19 may contribute to the decreased spermatogenesis in the offspring.

Focus on: biomarkers of fetal alcohol exposure and fetal alcohol effects

One of the ongoing challenges for the accurate diagnosis and treatment of children with fetal alcohol spectrum disorders (FASD) is the difficulty of confirming whether a mother drank during her pregnancy. Commonly used screening questionnaires often are unreliable, and current established biomarkers of alcohol consumption are not sensitive enough for use with many pregnant women. These limitations underscore the critical need to develop novel biomarkers with greater sensitivity for detecting moderate levels of drinking during pregnancy for longer periods of time after the last drinking episode. In addition, developing reliable biomarkers of fetal alcohol effects that can identify children at risk for adverse neurobehavioral outcomes could lead to behavioral interventions earlier in development. The use of animal models of FASD in biomarker development could accelerate progress in this challenging field of research.

Focus on: the use of animal models for the study of fetal alcohol spectrum disorders

Considerable efforts to educate women not to abuse alcohol during pregnancy have failed to reduce the incidence of fetal alcohol syndrome. Therefore, other approaches to limit the effects of prenatal alcohol exposure are under consideration, including the development of prevention programs and interventions. For these strategies to be as successful as possible, it also is important to improve methods for identifying affected children. The use of animal models in prenatal alcohol exposure research is critical because of the practical and ethical limitations of using human subjects for such studies. This article reviews the use of animal models in three areas of research: addressing basic questions about alcohol exposure during development; improving the identification of affected individuals; and developing approaches to reduce the impact of prenatal alcohol exposure. The various animal-model systems that have been used to study fetal alcohol spectrum disorders, each with their own specific strengths, have provided new findings that have been successfully extrapolated to human subjects, resulting in advancement of the research field and our understanding of fetal alcohol spectrum disorders.

Alcohol-induced facial dysmorphology in C57BL/6 mouse models of fetal alcohol spectrum disorder

Alcohol consumption during pregnancy causes fetal alcohol spectrum disorder (FASD), which includes a range of developmental deficits. Fetal alcohol syndrome is the most severe form of FASD and can be diagnosed with pathognomonic facial features such as a smooth philtrum, short palpebral fissure, and thin upper vermilion. However, many children with developmental damage because of prenatal alcohol exposure exhibit none, or only a subset, of the above features, making diagnosis difficult. This study explored novel analyses to quantify the effect of a known dose of alcohol on specific facial measurements in substrains C57BL/B6J (B6J) and C57BL/6NHsd (B6N) mice. Mouse dams were provided alcohol (Alc) consisting of 4.8% (vol/vol) alcohol in a liquid diet for 16 days prepregnancy and chow and water diet during mating, and then the alcohol liquid diet was reinstated on gestational days 7 (E7) to gestational day 17 (E17). Treatment controls included a pair-fed (PF) group given matched volumes of an alcohol-free liquid diet made isocalorically and a group given ad lib access to lab chow and water (Chow). Maternal diet intake (Alc and PF), blood alcohol concentrations (BACs), embryo weights, and 15 morphometric facial measurements for E17 embryos were analyzed. B6N dams drank more alcohol during pregnancy and generated higher BAC than B6J dams. Both the Alc and PF treatments induced significant reductions in embryo weights relative to Chow in both substrains. Alcohol treatments produced significant changes, relative to controls, in 4 of the 15 facial measures for the B6N substrain but only in two measures for the B6J substrain. Discriminant analysis demonstrated successful classification of the alcohol-exposed versus nonalcohol-exposed B6N embryos, with a high sensitivity of 86%, specificity 80%, and overall classification (total correct 83%), whereas B6J mice yielded sensitivity of 80%, specificity 78%, and overall correct classification in 79%. In addition, B6N mice showed significantly more effects of pair feeding on these facial measures than did B6J mice, suggesting that the B6N substrain may be more vulnerable to nutritional stress during pregnancy. Overall, these data indicate that both B6N and B6J mice were vulnerable to alcohol but show differences in the severity and location of alcohol-induced dysmorphic facial features and may parallel findings from human studies comparing different ethnic groups. Furthermore, these findings suggest that discriminant analysis may be useful in predicting alcohol exposure in either mouse substrains.

Folate protection from congenital heart defects linked with canonical Wnt signaling and epigenetics

PURPOSE OF REVIEW

Environmental factors, such as drugs, chemicals, or abnormal concentrations of natural metabolites, induce birth defects. Environmental effects on cardiogenesis have been little studied in contrast to neurogenesis. This review presents evidence on three environmental factors: alcohol, the drug lithium, and the metabolite homocysteine, impacting the Wnt/β-catenin pathway during cardiac development and folate protection.

RECENT FINDINGS

Animal and epidemiological studies have shown that folate protects the embryo from birth defects. New animal studies demonstrate that folate prevents cardiovascular defects induced by the drug lithium, homocysteine, or alcohol, but protection occurs at a higher concentration than currently used in vitamin supplements. The data indicate that folate in combination with myo-inositol may further reduce the risk of birth defects. Discussion is presented of the cell specification stages that are impacted resulting in cardiac defects, how Wnt/β-catenin signaling is involved, and how folate and myo-inositol additively may protect embryonic pathways. The possible epigenetic role of folate in Wnt/β-catenin signaling is described.

SUMMARY

This review will enable better counseling of women by defining, during early pregnancy, a susceptible window of embryonic exposure leading to a high risk of cardiac defects, and provides a therapeutic means and the necessary timing for prevention of environmentally induced birth defects.

Fetal alcohol syndrome: cardiac birth defects in mice and prevention with folate

OBJECTIVE

Alcohol (ethanol) consumption during pregnancy is linked to congenital heart defects that are associated with fetal alcohol syndrome. Recent reports have associated ethanol exposure with the Wnt/beta-catenin pathway. Therefore, we defined whether ethanol affects Wnt/beta-catenin signaling during cardiac cell specification.

STUDY DESIGN

Pregnant mice on embryonic day 6.75 during gastrulation were exposed by an intraperitoneal injection to a binge-drinking dose of ethanol. Folic acid supplementation of mouse diet was tested for the prevention of ethanol-induced cardiac birth defects.

RESULTS

Acute ethanol exposure induced myocardial wall changes and atrioventricular and semilunar valve defects, which was determined by echocardiography on embryonic day 15.5. A high folate diet prevented the ethanol-induced cardiac defects. Ethanol exposure in avian embryos suppressed 2 key Wnt-modulated genes that are involved in cardiac induction; folic acid rescued normal gene expression.

CONCLUSION

Folic acid supplementation alone or with myoinositol prevented alcohol potentiation of Wnt/beta-catenin signaling that allowed normal gene activation and cardiogenesis.

Alteration of selective neurotransmitters in fetal brains of prenatally alcohol-treated C57BL/6 mice: quantitative analysis using liquid chromatography/tandem mass spectrometry

We previously demonstrated that prenatal alcohol exposure results in brain defects at different embryonic stages. This study is aimed at characterizing the influence of prenatal alcohol exposure on the levels of several neurotransmitters at early embryonic stage 13 (E13). Pregnant C57BL/6 mice were exposed to either a 25% ethanol derived calorie diet (ALC) or pair-fed (PF) liquid diet from E7 to E13. At E13, fetal brains were collected from dams of the ALC and PF groups. Liquid chromatography/tandem mass spectrometry (LC-MS) was then used to evaluate neurotransmitter levels. This approach involved the use of an LC column in conjunction with multiple-reaction monitoring mass spectrometry. Quantitative analyses of catecholamines, idolamine, and amino acid neurotransmitters revealed significant reductions in the levels of dopamine (p=0.004), norepinephrine (p=0.0009), epinephrine (p=0.0002), serotonin (p=0.004), and GABA (p=0.002) in the ALC group compared to the PF group. However, there was no significant change in the levels of glutamate in E13 fetal brains. These findings demonstrate that prenatal alcohol exposure reduces the concentrations of some catecholamines, idolamine, and amino acid neurotransmitters in E13 fetal brains. This study suggests that alterations of selective neurotransmitters may be the cause of abnormalities in brain function and behavior found in fetal alcohol spectrum disorders.

Proteomic technologies for prenatal diagnostics: advances and challenges ahead

Proteomics-based identification of biomarkers for fetal abnormalities in maternal plasma, amniotic fluid and reproductive fluids has made significant progress in the past 5 years. This is attributed mainly to advances in various technology platforms associated with mass spectrometry-based techniques. As these techniques are highly sensitive and require only small quantities of body fluids, it is hoped that they will pave the way for the development of effective noninvasive approaches, without subjecting the developing fetus to the same degree of harm as current invasive procedures (e.g., amniocentesis). It is possible that these developments will include same-day analyses, thereby permitting rapid intervention when necessary. To date, a host of body fluids, such as maternal serum and plasma, amniotic fluid, cervical fluid, vaginal fluid, urine, saliva or fetal material, such as placental trophoblast, fetal membranes or cord blood, have been used successfully in the quest to develop markers for a number of pregnancy-related pathologies. In the current review update we focus on the emergence of proteomics as a major platform technology in studying various types of fetal conditions and developing markers for pregnancy-related disorders, such fetal aneuploidy, preterm birth, preeclampsia, intra-amniotic infection and fetal stress. Should the development of these markers be successful, then it is to be envisaged that proteomic approaches will become standard of care for a number of disease conditions associated with feto-maternal health.