Teratology in the 20th century

Updating an Overview of Teratology

In this chapter, the authors aim to update an overview of the principles of teratology, beginning with the definition of teratology, the critical point at which this process occurs, and some of the most common etiological agents that improve our understanding of teratology.Modern teratology has greatly improved in recent years with advances in new methods in molecular biology, toxicology, animal laboratory science, and genetics, increasing our knowledge of ambient influences. Nevertheless, there is a lot to do to reduce the influence of hazardous intervening agents, whether they target our genetics or not, that can negatively affect pregnancy and induce congenital development disorders, including morphological, biochemical, or behavioral defects.Certain agents might indeed be related to certain defects, but we have not been able to identify the cause of most congenital defects, which highlights the importance of finding and testing out new genetics techniques and conducting laboratory animal science to unravel the etiology and pathogenicity of each congenital defect.

Impact of Prenatal Alcohol Exposure on the Development and Myocardium of Adult Mice: Morphometric Changes, Transcriptional Modulation of Genes Related to Cardiac Dysfunction, and Antioxidant Cardioprotection

The impact of prenatal alcohol exposure (PAE) varies considerably between individuals, leading to morphological and genetic changes. However, minor changes usually go undetected in PAE children. We investigated PAE's effects on gene transcription of genes related to cardiac dysfunction signaling in mouse myocardium and morphological changes. C57Bl/6 mice were subjected to a 10% PAE protocol. In postnatal days 2 and 60 (PN2 and PN60), morphometric measurements in the offspring were performed. Ventricular samples of the heart were collected in PN60 from male offspring for quantification of mRNA expression of 47 genes of nine myocardial signal transduction pathways related to cardiovascular dysfunction. Animals from the PAE group presented low birth weight than the Control group, but the differences were abolished in adult mice. In contrast, the mice's size was similar in PN2; however, PAE mice were oversized at PN60 compared with the Control group. Cardiac and ventricular indexes were increased in PAE mice. PAE modulated the mRNA expression of 43 genes, especially increasing the expressions of genes essential for maladaptive tissue remodeling. PAE animals presented increased antioxidant enzyme activities in the myocardium. In summary, PAE animals presented morphometric changes, transcription of cardiac dysfunction-related genes, and increased antioxidant protection in the myocardium.

The environments of reproductive and birth defects research in the U.S. and West Germany (c. 1955-1975)

Most historiographies of the crossroads of environmental and reproductive health in 20th century start and end with the case of thalidomide. Despite its global scope, thalidomide today stands for sharp contrasts: in the numbers of victims, in institutional responses to the disaster, and also-more generally-in regulatory approaches to potential risks and national cultures of reproductive justice and disability rights. This paper takes a closer look at two countries that have been seen as emblematic of this divide in regulatory frameworks, despite similarities and interconnections in other areas, such as (pharma)industrial production, science, and robust feminist environmental health movements: the U.S. and West Germany. It argues that thalidomide needs to be historically contextualized within a broad framework of concepts and models of environment from research on exogenous reproductive effects. To do so, it reconstructs what counted as environment in research on reproductive health and birth defects in these two national settings in the postwar decades. It looks at transformations made across multifaceted initiatives, studying collective landscapes and workplaces as potentially dangerous "outer worlds," as well as smaller scale and more individualized environments, i.e., the maternal metabolism, uterus, lifestyle, or social interactions. The article thereby aims to explicate concepts and debates about the environment that influenced later national divisions in politics of science and technology, hinting of the democratic challenges these posed.

The Duogynon controversy and ignorance production in post-thalidomide West Germany

This article examines the West German controversy over Duogynon, a 'hormone pregnancy test' and the drug at the centre of the first major, international debate over iatrogenic birth defects in the post-thalidomide era. It recovers an asymmetrical power struggle over the uneven distribution of biomedical knowledge and ignorance (about teratogenic risk) that pitted parent-activists, whistleblowers and investigative journalists against industrialists, scientific experts and government officials. It sheds new light on the nexus of reproduction, disability, epidemiology and health activism in West Germany. In addition, it begins to recover an internationally influential discourse that, in the post-thalidomide world, seems to have resuscitated antenatal drug use as safe until proven harmful.

Investigating disagreement in the scientific literature

Disagreement is essential to scientific progress but the extent of disagreement in science, its evolution over time, and the fields in which it happens remain poorly understood. Here we report the development of an approach based on cue phrases that can identify instances of disagreement in scientific articles. These instances are sentences in an article that cite other articles. Applying this approach to a collection of more than four million English-language articles published between 2000 and 2015 period, we determine the level of disagreement in five broad fields within the scientific literature (biomedical and health sciences; life and earth sciences; mathematics and computer science; physical sciences and engineering; and social sciences and humanities) and 817 meso-level fields. Overall, the level of disagreement is highest in the social sciences and humanities, and lowest in mathematics and computer science. However, there is considerable heterogeneity across the meso-level fields, revealing the importance of local disciplinary cultures and the epistemic characteristics of disagreement. Analysis at the level of individual articles reveals notable episodes of disagreement in science, and illustrates how methodological artifacts can confound analyses of scientific texts.

The Use of Human Induced Pluripotent Stem Cells for Testing Neuroprotective Activity of Pharmacological Compounds

Development of therapeutic preparations involves several steps, starting with the synthesis of chemical compounds and testing them in different models for selecting the most effective and safest ones to clinical trials and introduction into medical practice. Cultured animal cells (both primary and transformed) are commonly used as models for compound screening. However, cell models display a number of disadvantages, including insufficient standardization (primary cells) and disruption of cell genotypes (transformed cells). Generation of human induced pluripotent stem cells (IPSCs) offers new possibilities for the development of high-throughput test systems for screening potential therapeutic preparations with different activity spectra. Due to the capacity to differentiate into all cell types of an adult organism, IPSCs are a unique model that allows examining the activity and potential toxicity of tested compounds during the entire differentiation process in vitro. In this work, we demonstrated the efficiency of IPSCs and their neuronal derivatives for selecting substances with the neuroprotective activity using two classes of compounds - melanocortin family peptides and endocannabinoids. None of the tested compounds displayed cyto- or embryotoxicity. Both melanocortin peptides and endocannabinoids exerted neuroprotective effect in the neuronal precursors and IPSC-derived neurons subjected to hydrogen peroxide. The endocannabinoid N-docosahexaenoyl dopamine exhibited the highest neuroprotective effect (~70%) in the differentiated cultures enriched with dopaminergic neurons; the effect of melanocortin Semax was ~40%. The possibility of using other IPSC derivatives for selecting compounds with the neuroprotective activity is discussed.

Inclusion and exclusion in the history of developmental biology

Scientific disciplines embody commitments to particular questions and approaches, scopes and audiences; they exclude as well as include. Developmental biology is no exception, and it is useful to reflect on what it has kept in and left out since the field was founded after World War II. To that end, this article sketches a history of how developmental biology has been different from the comparative, human and even experimental embryologies that preceded it, as well as the embryology that was institutionalized in reproductive biology and medicine around the same time. Early developmental biology largely excluded evolution and the environment, but promised to embrace the entire living world and the whole life course. Developmental biologists have been overcoming those exclusions for some years, but might do more to deliver on the promises while cultivating closer relations, not least, to reproductive studies.

Histopathological Findings in the Viscera of Malformed Neotropical Viperids

Congenital malformations (CMs) or developmental abnormalities are pathological processes defined as morphological defects that originate during embryonic stages. A wide variety of CMs is observed in reptiles, most of which are incompatible with normal life. Characterization of CMs and their pathogenesis are of great importance for the conservation of reptiles, including neotropical viperids (NVs). External CMs are often reported in these species, but little is known about concomitant microscopical findings in the viscera of malformed individuals. In order to partially fill in this gap in knowledge, we aimed to investigate and characterize histopathological findings in the viscera of malformed NVs, jararacas (Bothrops jararaca) and South American rattlesnakes (Crotalus durissus), correlating these findings with features of external CMs. From 78 malformed snakes analysed, 100% (19/19) of rattlesnakes and 98.3% (58/59) of jararacas had histopathological changes in the viscera. Liver and/or kidney fatty degeneration was the most common finding in malformed and control animals. Renal glomerulocystic and tubular disease was significantly correlated with brachygnathia (P < 0.05) in jararacas. These results add to the body of knowledge of snake pathology and demonstrate some associations between external CMs and visceral histopathological findings, some of which could have implications for individual survival.

An Overview of Teratology

In this chapter, we provide an overview of the basic principles of teratology, beginning with its definition, the critical point for teratogenesis to occur and the most evident etiological agents to improve the understanding of this science.Teratology is a recent science that began in the early twentieth century, and has greatly improved over the recent years with the advancements in molecular biology, toxicology, animal laboratory science, and genetics, as well as the improvement on the knowledge of the environmental influences.Nevertheless, more work is required to reduce the influence of hazardous products that could be deleterious during pregnancy, thus reducing teratogenic defects in the newborn. While some teratogenic defects are attributed to their agents with certainty, the same for a lot of other such defects is lacking, necessitating consistent studies to decipher the influence of various teratogenic agents on their corresponding teratogenic defects. It is here that the laboratory animal science is of great importance both in the present and in the future.

Teratogens: a public health issue - a Brazilian overview

Congenital anomalies are already the second cause of infant mortality in Brazil, as in many other middle-income countries in Latin America. Birth defects are a result of both genetic and environmental factors, but a multifactorial etiology has been more frequently observed. Here, we address the environmental causes of birth defects - or teratogens - as a public health issue and present their mechanisms of action, categories and their respective maternal-fetal deleterious effects. We also present a survey from 2008 to 2013 of Brazilian cases involving congenital anomalies (annual average of 20,205), fetal deaths (annual average of 1,530), infant hospitalizations (annual average of 82,452), number of deaths of hospitalized infants (annual average of 2,175), and the average cost of hospitalizations (annual cost of $7,758). Moreover, we report on Brazilian cases of teratogenesis due to the recent Zika virus infection, and to the use of misoprostol, thalidomide, alcohol and illicit drugs. Special attention has been given to the Zika virus infection, now proven to be responsible for the microcephaly outbreak in Brazil, with 8,039 cases under investigation (from October 2015 to June 2016). From those cases, 1,616 were confirmed and 324 deaths occurred due to microcephaly complications or alterations on the central nervous system. Congenital anomalies impact life quality and raise costs in specialized care, justifying the classification of teratogens as a public health issue.

Effects of Folic Acid and Homocysteine on the Morphogenesis of Mouse Cephalic Neural Crest Cells In Vitro

Folate deficiency and hyperhomocysteinemia have long been associated with developmental anomalies, particularly neural tube defects and neurocristopathies-a group of diverse disorders that result from defective growth, differentiation, and migration of neural crest (NC) cells. However, the exact mechanisms by which homocysteine (Hcys) and/or folate deficiencies disrupt NC development are still poorly understood in mammals. In this work, we employed a well-defined culture system to investigate the effects of Hcys and folic acid (FA) supplementation on the morphogenetic processes of murine NC cells in vitro. We demonstrated that Hcys increases outgrowth and proliferation of cephalic NC cells and impairs their differentiation into smooth muscle cells. In addition, we showed that FA alone does not directly affect the developmental dynamics of the cephalic NC cells but is able to prevent the Hcys-induced effects. Our results, therefore, suggest that elevated Hcys levels per se cause dysmorphogenesis of the cephalic NC and might contribute to neurocristopathies in mammalian embryos.

Low Risk of Birth Defects for Infants Whose Mothers Are Treated With Anti-Tumor Necrosis Factor Agents During Pregnancy

BACKGROUND & AIMS

Safety data on anti-tumor necrosis factor (anti-TNF) treatment during pregnancy are limited. We studied the risk of birth defects after anti-TNF treatment in early pregnancy.

METHODS

We collected data on 1,272,424 live-born infants identified from the Danish (2004-2012) and Swedish (2006-2012) population-based health registers. We determined the prevalence of birth defects among infants born to women with chronic inflammatory disease (inflammatory bowel disease, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, or psoriasis), with (n = 683) and without (n = 21,549) anti-TNF treatment during early pregnancy, and in the general population. We compared the risk of any major birth defect and birth defect by organ system for infants born to women with chronic inflammatory disease, with and without anti-TNF treatment. Risks were presented as odds ratios (ORs) with 95% confidence intervals (CIs). We adjusted for maternal age, parity, smoking, body mass index, multiple gestation, country, and chronic inflammatory diagnosis.

RESULTS

Birth defects were more prevalent among infants born to women with chronic inflammatory disease, regardless of anti-TNF treatment status, than in the general population (4.8% vs 4.2%). Birth defects occurred in 43 of the infants born to the 683 women who received anti-TNF treatment (6.3%), and 1019 of the infants born to women with chronic inflammatory disease (4.7%). The OR for any defect in women receiving anti-TNF therapy was 1.32 (95% CI, 0.93-1.82); the OR for a cardiovascular defect was 1.60 (95% CI, 0.93-2.58), and the OR for a urinary defect was 2.22 (95% CI, 0.86-4.71).

CONCLUSIONS

Based on an analysis of data from the health registries in Denmark and Sweden, women who received anti-TNF agents during pregnancy had a slightly (but not significantly) higher risk of having children with birth defects. Although larger studies are needed, the heterogeneity of the observed birth defects did not indicate a common etiology.

Minor Physical Anomalies as a Window into the Prenatal Origins of Pedophilia

Evidence is steadily accumulating to support a neurodevelopmental basis for pedophilia. This includes increased incidence of non-right-handedness, which is a result primarily of prenatal neural development and solidified very early in life. Minor physical anomalies (MPAs; superficial deviations from typical morphological development, such as un-detached earlobes) also develop only prenatally, suggesting them as another potential marker of atypical physiological development during the prenatal period among pedophiles. This study administered the Waldrop Physical Anomaly Scale to assess the prevalence of MPAs in a clinical sample of men referred for assessment following a sexual assault, or another illegal or clinically significant sexual behavior. Significant associations emerged between MPA indices and indicators of pedophilia, including penile responses to depictions of children, number of child victims, and possession of child pornography. Moreover, greater sexual attraction to children was associated with an elevated craniofacial-to-peripheral anomalies ratio. The overall sample demonstrated a greater number of MPAs relative to prior samples of individuals with schizophrenia as well as to healthy controls.

'Something there is that doesn't love a wall': histories of the placental barrier

This article appraises the late twentieth century maxim that prior to thalidomide's clarion call in 1961, a generic "we" believed that the fetus was protected from external insult by the placental barrier. Complicating this truism, we demonstrate that the placenta was, since early in the twentieth century, conceived of as a site of constant passage of entities both necessary to, and dangerous for, fetal development. Moving between evidence from specialist journals, obstetrics textbooks, and pregnancy advice manuals, we argue that the placental barrier writ large only emerged as an explicit actor after the medical community was disillusioned with it: it became something that does not exist. The article proposes that the nostalgia for a barrier lost constructs the modern-day fetus as more exposed and vulnerable than if "we" had never imagined this protection in the first place. The rhetorical shorthand of the erstwhile placental barrier has both deflected more nuanced accounts of the thalidomide story and contributed to the increasing surveillance of pregnant women's behavior, particularly in late twentieth century North America.

Food, growth and time: Elsie Widdowson's and Robert McCance's research into prenatal and early postnatal growth

Cambridge scientists Robert McCance and Elsie Widdowson are best known for their work on the British food tables and wartime food rations, but it is their research on prenatal and early postnatal growth that is today seen as a foundation of the fields studying the impact of environment upon prenatal development and, consequently, adult disease. In this essay I situate McCance's and Widdowson's 1940s human and 1950s experimental studies in the context of pre-war concerns with fetal growth and development, especially within biochemistry, physiology and agriculture; and the Second World War and post-war focus on the effects of undernutrition during pregnancy upon the fetus. I relate Widdowson's and McCance's research on the long-term effects of early undernutrition to the concern with recovery from early trauma so pertinent in post-war Europe and with sensitive (critical) periods, a concept of high importance across different fields. Finally I discuss how, following a hiatus in which fetal physiology engaged with different questions and stressed fetal autonomy, interest in the impact of environment upon prenatal growth and development revived towards the end of the twentieth century. The new field of "developmental origins of health and disease", I suggest, has provided a context in which Widdowson's and McCance's work has regained importance.

Birth defects and epilepsy medication

Epilepsy is one of the most common neurological problems in pregnancy. Approximately one in 200 pregnancies is to a woman with epilepsy taking antiepileptic drugs. For the majority of women, pregnancy proceeds without any apparent difficulties but there is growing evidence of an increased risk of major malformations and later cognitive problems in children exposed to antiepileptic drugs in utero. This review summarizes the available evidence for these risks and examines the implications of these in the counseling and treatment of women with epilepsy.

Association GSTT1, GSTM1 and GSTP1 (Ile105Val) genetic polymorphisms in mothers with risk of congenital malformations in their children in Western Siberia: a case-control study

OBJECTIVE

Polymorphisms of glutathione S-transferase (GST) genes in mothers may be involved in teratogenesis in their offspring. This study aims to investigate the association of GST genes (T1, M1 and P1) with the risk of having children with congenital malformations (CMs) in residents of the West Siberian region of Russia.

METHOD

We studied 235 women with offspring's with CMs, and 273 women with one or more healthy children. Null genotypes of GSTM1 and GSTT1 were identified through multiplex real-time polymerase chain reaction, and GSTP1 gene (Ile105Val) polymorphism was determined through TaqMan-real-time polymerase chain reaction.

RESULTS

The study showed that the maternal genotype GSTT1 «0/0» is associated with CMs in the offspring (odd ratio (OR) = 3.63, P = 5.18 × 10(-9) ). A significant association of the maternal genotype GSTT1 «0/0» with CMs of the cardiovascular system (OR = 5.03, P = 2.93 × 10(-7) ), urinary system (OR = 4.20, P = 3.51 × 10(-6) ) and central nervous system (OR = 4.40, P = 6.69 × 10(-5) ) was found in the child. No association of maternal GSTM1 (del) and GSTP1 (Ile105Val) genetic polymorphisms with CMs of the child was identified.

CONCLUSION

Homozygous deletion of the GSTT1 gene in women of the West Siberian region is a risk factor for birth defects in the child.

Homocysteine causes disruptions in spinal cord morphology and changes the expression of Pax 1/9 and Sox 9 gene products in the axial mesenchyme

BACKGROUND

Neural tube defects (NTD) involve disruptions in the axial mesenchyme, and are related to an imbalance between folic acid (FA) and homocysteine (Hcy). This study evaluated the effects of FA/Hcy imbalance on cell proliferation and expression of the Pax 1/9 and Sox 9 gene products in the axial mesenchyme of chickens.

METHODS

Embryos were incubated (38°C) and pretreated at 24 h and treated at 46 h of incubation. The experimental groups were: FA-pretreated with saline and treated with 0.5 μg FA/saline; Hcy-pretreated with 50 μl saline and treated with 20 μmol D,L-Hcy/50 μl saline; FA+Hcy-pretreated with 0.5 μg FA/50 μl saline and treated with 20 μmol D,L-Hcy/50 μl saline; and the control embryos were pretreated and treated with saline. Embryos were analyzed at E4 and E6. Immunohistochemistry was performed to identify proliferating cells and the expression of the gene products of Pax 1/9 and Sox 9. Total RNA of the E4 embryos was extracted and a RT-qPCR assay was performed to quantify Pax 1/9 mRNA expression.

RESULTS

Hcy treatment caused spinal NTD and abnormalities in axial mesenchyme development, affecting the distribution of sclerotomal cells and chondrification. Hcy also reduced cell proliferation and changed the expression of Pax 1/9 and Sox 9 in the mesenchyme.

CONCLUSIONS

Our data clarified the relationship between spinal NTD genesis and disruptions of Pax 1/9 and Sox 9 gene products in the axial mesenchyme caused by the FA/Hcy imbalance.

Hyperglycemia slows embryonic growth and suppresses cell cycle via cyclin D1 and p21

In pregnant women, the diabetic condition results in a three- to fivefold increased risk for fetal cardiac malformations as a result of elevated glucose concentrations and the resultant osmotic stress in the developing embryo and fetus. Heart development before septation in the chick embryo was studied under two hyperglycemic conditions. Pulsed hyperglycemia induced by daily administration of glucose during 3 days of development caused daily spikes in plasma glucose concentration. In a second model, sustained hyperglycemia was induced with a single injection of glucose into the yolk on day 0. The sustained model raised the average plasma glucose concentration from 70 mg/dL to 180 mg/dL and led to decreased gene expression of glucose transporter GLUT1. Both models of hyperglycemia reduced embryo size, increased mortality, and delayed development. Within the heart outflow tract, reduced proliferation of myocardial and endocardial cells resulted from the sustained hyperglycemia and hyperosmolarity. The cell cycle inhibitor p21 was significantly increased, whereas cyclin D1, a cell cycle promoter, decreased in sustained hyperglycemia compared with controls. The evidence suggests that hyperglycemia-induced developmental delays are associated with slowed cell cycle progression, leading to reduced cellular proliferation. The suppression of critical developmental steps may underlie the cardiac defects observed during late gestation under hyperglycemic conditions.

[The thalidomide experience: review of its effects 50 years later]

This year is the 50(th) anniversary of the discovery that the drug thalidomide causes birth defects and should therefore be considered as a teratogen. However, despite the existence of several other drugs that are also human teratogens, thalidomide continues to cause concern among health professionals as well as the general population. The objectives of this article are to make a short historical review of the discovery that this drug severely alters the embryo development, the critical period of gestation and the identification of the real effect of thalidomide. For the first time an analysis is provided to identify the type of malformations for which thalidomide really increases the risk. The proportions of the different types of malformations groups from the series of patients considered to be affected by thalidomide from the literature were compared with the proportions of the same malformations groups in non-exposed infants from the Spanish Collaborative Study of Congenital Malformation (ECEMC). The aim of the analysis was to calculate the relative frequencies of 13 groups of malformations observed in series of patients exposed to thalidomide, by comparison with the same groups of defects in 1,491 patients with limb malformations from the ECEMC consecutive newborn infants, non-exposed to thalidomide. The results showed that the groups with the most classical limb malformations attributed to thalidomide (phocomelia, thumb absence/hypoplasia) had a significantly very higher frequency in exposed cases than in the ECEMC's cases. However, cases presenting with only lower limb malformations were 3 times less frequent in thalidomide cases than in those of ECEMC. Finally, other groups presented the same frequency as those observed in the ECEMC's cases. The results of the 2 last groups, strongly suggests that they were not due to the effect of thalidomide. In addition to the short historical review of the teratogenicity risk of thalidomide, and their new therapeutic properties, it is documented that, as it happens with all other currently known human teratogens, not all malformations observed in infants prenatally exposed to thalidomide were caused by this drug. Finally, it is discussed the paradox that the «feared» thalidomide drug causing a great human drama affecting about 10,000 infants has led to a formidable contribution to the scientific knowledge, and large range of therapeutic applications.

Teratogenic exposures

A consideration of teratogenic exposures includes not only an agent (chemical, radiation, biologic) but an exposure level and timing of exposure. There are criteria by which exposures are evaluated for a causal connection with an abnormal outcome. We here review some teratogenic exposures and discuss how they were initially described and confirmed. We have limited our discussion to some of the exposures for which a connection to structural malformations has been accepted in some quarters, and we indicate some exposures for which a causal association awaits confirmation. We recommend that counselors find a reliable and updatable source of information on exposures during pregnancy.

Alteration of gene expression by alcohol exposure at early neurulation

BACKGROUND

We have previously demonstrated that alcohol exposure at early neurulation induces growth retardation, neural tube abnormalities, and alteration of DNA methylation. To explore the global gene expression changes which may underline these developmental defects, microarray analyses were performed in a whole embryo mouse culture model that allows control over alcohol and embryonic variables.

RESULT

Alcohol caused teratogenesis in brain, heart, forelimb, and optic vesicle; a subset of the embryos also showed cranial neural tube defects. In microarray analysis (accession number GSM9545), adopting hypothesis-driven Gene Set Enrichment Analysis (GSEA) informatics and intersection analysis of two independent experiments, we found that there was a collective reduction in expression of neural specification genes (neurogenin, Sox5, Bhlhe22), neural growth factor genes [Igf1, Efemp1, Klf10 (Tieg), and Edil3], and alteration of genes involved in cell growth, apoptosis, histone variants, eye and heart development. There was also a reduction of retinol binding protein 1 (Rbp1), and de novo expression of aldehyde dehydrogenase 1B1 (Aldh1B1). Remarkably, four key hematopoiesis genes (glycophorin A, adducin 2, beta-2 microglobulin, and ceruloplasmin) were absent after alcohol treatment, and histone variant genes were reduced. The down-regulation of the neurospecification and the neurotrophic genes were further confirmed by quantitative RT-PCR. Furthermore, the gene expression profile demonstrated distinct subgroups which corresponded with two distinct alcohol-related neural tube phenotypes: an open (ALC-NTO) and a closed neural tube (ALC-NTC). Further, the epidermal growth factor signaling pathway and histone variants were specifically altered in ALC-NTO, and a greater number of neurotrophic/growth factor genes were down-regulated in the ALC-NTO than in the ALC-NTC embryos.

CONCLUSION

This study revealed a set of genes vulnerable to alcohol exposure and genes that were associated with neural tube defects during early neurulation.

Environmental exposures and development

PURPOSE OF REVIEW

Summarize recent studies exploring the relationship between paternal and maternal environmental exposures to chemicals before, at the time of and after conception to adverse developmental outcomes including preterm birth, death, structural and functional abnormalities and growth restriction.

RECENT FINDINGS

Recent studies have demonstrated that human pregnancy and development are vulnerable to environmental exposures of the father and mother to chemical, biological and physical agents. Exposures associated with adverse developmental outcomes include air and water pollution, chemicals in foods, occupational exposures, agricultural chemicals, metals, persistent and volatile organics. Developmental endpoints which are linked with these exposures include growth restriction, functional abnormalities, structural abnormalities, preterm delivery and death. Despite this general understanding we still have incomplete knowledge concerning most exposures and the biological interactions responsible for impaired development and preterm delivery.

SUMMARY

Whereas single genes and individual chemical exposures are responsible for some instances of adverse pregnancy outcome or developmental disease, gene-environment interactions are responsible for the majority. These gene-environment interactions may occur in the father, mother, placenta or fetus, suggesting that critical attention be given to maternal and paternal exposures and gene expression as they relate to the mode of action of the putative developmental toxicant both prior to and during pregnancy.

Effects of ethanol on mouse embryonic stem cells

BACKGROUND

Fetal alcohol syndrome (FAS) reflects a constellation of congenital abnormalities caused by excess maternal consumption of alcohol. It is likely that interference with embryonic development plays a role in the pathogenesis of the disorder. Ethanol-induced apoptosis has been suggested as a causal factor in the genesis of FAS. Mouse embryonic stem (mES) cells are pluripotent cells that differentiate in vitro to cell aggregates termed embryoid bodies (EBs), wherein differentiation capacity and gene expression profile are similar to those of the early embryo.

METHODS

To investigate the effects of ethanol during differentiation, mES cells were cultured on a gelatin surface in the presence of leukemia inhibitory factor which maintains adherent undifferentiated cells or in suspension to promote formation of EBs. All cells were treated (1-6 days) with 80 mM ethanol. The pluripotency and differentiation of mES cells were evaluated by western blotting of stage-specific embryonic antigen (SSEA-1), transcription factors Oct-3/4, Sox-2, and Nanog, using alkaline phosphatase staining. Apoptosis (early to late stages) was assessed by fluorescence-activated cell sorting using TdT-mediated biotin-dUTP nick-end labelling assay and fluorescein isothiocyanate-Annexin V/propidium iodide staining.

RESULTS

Ethanol increased apoptosis during in vitro differentiation of mES cells to EBs, whereas undifferentiated cells were not affected. Ethanol exposure also interfered with pluripotency marker patterns causing an upregulation of SSEA-1 under self-renewal conditions. In EBs, ethanol delayed the downregulation of SSEA-1 and affected the regulation of transcription factors during differentiation.

CONCLUSION

Our findings suggest that ethanol may contribute to the pathogenesis of FAS by triggering apoptotic pathways during differentiation of embryonic stem cells and deregulating early stages of embryogenesis.

Environmental health and developmental disabilities: a life span approach

Prenatal and childhood environmental exposures are an underrecognized primary cause of intellectual and other developmental disabilities. In addition, individuals with established disabilities are vulnerable to further harm from subsequent environmental exposures. In individuals with communicative impairment or limited ability to independently escape from hazards, these subsequent exposures, too, may occur undetected or untreated. This article introduces the subject of environmental health and developmental disabilities throughout the life span. In particular, we focus on ways that families, communities, and health professionals can prevent both primary and secondary disabilities through better awareness of common environmental health issues.

Therapeutic monitoring of antiepileptic drugs during pregnancy and in the postpartum period: is it useful?

As in all patient populations, epilepsy is common in pregnant women. Consequently, approximately 1 in 200 pregnancies is exposed to antiepileptic drugs (AEDs). Although exposure to AEDs in utero has been associated with an increased risk of major fetal malformations, most women with epilepsy require medication throughout pregnancy, since seizures themselves may be potentially harmful not only for the mother but also for the developing fetus. Physiological changes during pregnancy result in a reduction in the serum concentrations of most AEDs, particularly in late pregnancy. Changes in protein binding lead to a greater reduction in total than free (active) drug concentrations. Pharmacokinetic changes in pregnancy show interindividual variability and are not well understood for most newer AEDs. However, recent studies have shown that changes in lamotrigine clearance are particularly marked, with increases in each trimester and a significant fall in plasma concentrations, leading to consequent breakthrough seizures in some women. Concentrations may then rise precipitously after delivery, leading to symptoms of lamotrigine toxicity. Therapeutic drug monitoring could theoretically guide adjustment of AED dosage to achieve good seizure control while minimising fetal exposure, although there are several limitations to such monitoring. Firstly, there are wide interindividual variations in serum drug concentrations, with seizure control often correlating poorly with a given therapeutic range. Secondly, therapeutic ranges have not been well defined for newer AEDs and their measurement is often not always available. Thirdly, for highly protein-bound drugs, although measurement of free drug concentrations may more accurately reflect drug availability during pregnancy than total drug concentrations, assays for this are not always available and may be unreliable. Thus, it may be useful, prior to pregnancy, to establish the total and free drug concentrations required to achieve optimal seizure control in a given individual. Regular monitoring of AEDs has been advocated in each trimester and shortly after delivery, with adjustment of dosage to avoid seizure precipitation during pregnancy or symptoms of toxicity after birth. More frequent monitoring has been recommended for lamotrigine. However, aggressive drug monitoring of any AED has yet to be proven to be effective in improving seizure control or care. Furthermore, higher doses may be associated with a greater potential for teratogenicity and it is not yet known whether longer term adverse effects may be related to in utero exposure in the latter half of pregnancy. There is limited evidence about the relationship of maternal serum drug concentrations and teratogenicity. While there is a theoretical role for therapeutic drug monitoring in improving the risk-to-benefit ratio of AED therapy during pregnancy, there are many practical limitations. Future work is needed to clarify its role in improving seizure control during pregnancy and identifying serum drug concentrations that may be considered safe for fetal exposure.

Herbal medicines used during the first trimester and major congenital malformations: an analysis of data from a pregnancy cohort study

BACKGROUND

Major congenital malformations place a considerable burden on the affected child, the family and society. Any kind of medicine used during pregnancy might have a harmful impact; therefore, such practice has raised concerns. The objective of the current study was to explore the relationship between the use of herbal medicines by pregnant women during the first trimester of pregnancy and the risk of major congenital malformation in their live born infants.

METHODS

This was a cross-sectional analysis of data from a prospective pregnancy cohort, which was established between 1984 and 1987. To assemble the cohort, pregnant women of >or=26 weeks of gestation who came to the Taipei Municipal Maternal and Child Hospital in Taiwan for prenatal care were enrolled in the study and interviewed using a structured questionnaire. Detailed information, including herbal medicine use during different periods of pregnancy, was obtained during the interview. Past medical history, current obstetric data and details on conventional medicines used during pregnancy were abstracted from medical records. Data on birth weight, gestational duration and characteristics of live born infants were gathered from the Taiwan national birth register. Congenital malformation information was obtained from multiple sources: the newborn examination record (1984-7); the national death register (1984-2003); and Taiwan National Health Insurance data (1996-2000). Multiple logistic regression was used to estimate the odds ratio [OR] of major congenital malformation by herbal medicines used during the first trimester.

RESULTS

A total of 14,551 live births were analysed. After adjustment for confounding factors, taking huanglian during the first trimester of pregnancy was found to be associated with increased risk of congenital malformations of the nervous system (adjusted OR 8.62, 95% CI 2.54, 29.24). An-Tai-Yin was associated with an increased risk of congenital malformations of the musculoskeletal and connective tissues (adjusted OR 1.61, 95% CI 1.10, 2.36) and the eye (adjusted OR 7.30, 95% CI 1.47, 36.18).

CONCLUSION

We found evidence for a possible link between the use of specific herbal medicines during the first trimester of pregnancy and increased risks of specific groups of congenital malformations. We could not investigate whether the adverse effects were related to direct toxicity from the herbal medicines, or were from misuse, contamination or uncontrolled confounding. Nonetheless, we would advise caution regarding use of herbal medicines during pregnancy, and we suggest that further investigation of these findings is warranted.

Differential teratogenic effect of alcohol on embryonic development between C57BL/6 and DBA/2 mice: a new view

BACKGROUND

Alcohol exposure during the fetal stage generates variable severity in different organs, as seen in fetal alcohol syndrome and fetal alcohol effect. Whether genetic factors or conditions of alcohol exposure influence the susceptibility to alcohol-related developmental impairment remains a question.

METHODS

To investigate the contribution of genotype to the susceptibility to alcohol-induced toxicity during development beyond confounding maternal factors and variables of alcohol exposures, the authors tested the effect of alcohol exposure under definitive concentration using a whole embryonic culture of two inbred strains previously known to be vulnerable (C57BL/6 [C6]) or resistant (DBA/2 [D2]) to alcohol. On gestational day 8, embryos from each group bearing three to six somites were collected and then cultured for 44 hr in a medium added with 400 mg/dl of ethanol. The viability and morphological malformations, as well as developmental staging of the embryos, were all scored at the end of the culture.

RESULTS

The authors found, in contrast to previous reports, that alcohol treatment retarded embryonic growth and induced abnormalities, including the neural tube opening and the hypoplasia of the optic vesicle in both strains. However, alcohol specifically compromised the heart and caudal neural tube in C6, whereas it specifically decreased the number of somites and the development of branchial bars among others in D2.

CONCLUSIONS

These results demonstrated that both strains of embryos are vulnerable to the same amount and pattern of alcohol exposures at the same developmental stage, but each with unique vulnerability in specific organs, with alcohol having greater teratogenic effects in D2 than in C6. These differential vulnerabilities are results of greater genetic influence, rather than the maternal influence or conditions of alcohol.

Do maternal folate and homocysteine levels play a role in neurodevelopmental processes that increase risk for schizophrenia?

OBJECTIVE

Evidence from many different lines of research supports the hypothesis that schizophrenia is a disorder of development with etiological factors implicated as early as the second trimester in utero. We suggest that low maternal folate, acting to increase homocysteine levels, may provide a functional link between many of the identified prenatal risk factors and the hypothesized mechanisms whereby neurodevelopmental patterning deviates toward a schizophrenic potential.

METHODS

PubMed was searched from the present back to 1963, when elevated homocysteine was identified as a pathogen in homocystinuria as first described by Carson and colleagues (Arch Dis Child 1963;38:425-36). All articles for homocystinuria, homocysteine, folate, and development with schizophrenia were evaluated.

RESULTS

The findings from this review support the hypothesis that maternal low folate and high homocysteine levels may provide a potential teratogenic mechanism that increases the risk for developing schizophrenia.

CONCLUSION

The potential role of maternal folate deficiency and hyperhomocystinemia in the genesis of schizophrenia would extend the range of their known teratogenic effects. Given the potential for preventive treatment offered by this hypothesis, we believe further investigation into this mechanism is warranted.

Environmental influences during development and their later consequences for health and disease: implications for the interpretation of empirical studies

Early experience has a particularly great effect on most organisms. Normal development may be disrupted by early environmental influences; individuals that survive have to cope with the damaging consequences. Additionally, the responses required to cope with environmental challenges in early life may have long-term effects on the adult organism. A further set of processes, those of developmental plasticity, may induce a phenotype that is adapted to the adult environment predicted by the conditions of early life. A mismatch between prediction and subsequent reality can cause severe health problems in those human societies where economic circumstances and nutrition are rapidly improving. Understanding the underlying mechanisms of plasticity is, therefore, clinically important. However, to conduct research in this area, developmental plasticity must be disentangled from disruption and the adverse long-term effects of coping. The paper reviews these concepts and explores ways in which such distinctions may be made in practice.

Life-long echoes--a critical analysis of the developmental origins of adult disease model

The hypothesis that there is a developmental component to subsequent adult disease initially arose from epidemiological findings relating birth size to either indices of disease risk or actual disease prevalence in later life. While components of the epidemiological analyses have been challenged, there is strong evidence that developmental factors contribute to the later risk of metabolic disease--including insulin resistance, obesity, and heart disease--as well as have a broader impact on osteoporosis, depression and schizophrenia. We suggest that disease risk is greater when there is a mismatch between the early developmental environment (i.e., the phase of developmental plasticity) versus that experienced in mature life (i.e., adulthood), and that nutritional influences are particularly important. It is also critical to distinguish between those factors acting during the developmental phase that disrupt development from those influences that are less extreme and act through regulated processes of epigenetic change. A model of the relationship between the developmental and mature environment is proposed and suggests interventional strategies that will vary in different population settings.

Fetal cardiac anomalies and genetic syndromes

Cardiac anomalies may occur in isolation or can be part of a genetic syndrome. In this article, we describe some of the genetic syndromes commonly associated with cardiac anomalies where there are other sonographic features that may aid accurate prenatal diagnosis.

Prescription of Hazardous Drugs During Pregnancy

BACKGROUND

Prescribing drugs to pregnant women requires the balancing of benefits and risks. Only a small proportion of drugs are known to be harmful to the fetus, but for the vast majority of drugs little evidence of fetal safety exists.

AIM

To determine the prescription pattern of potentially and clearly harmful prescription drugs during pregnancy with reference to drug safety categorisation, and to define the drug groups primarily responsible for multiple drug use during pregnancy.

STUDY DESIGN

A retrospective, register-based cohort study.

METHODS

Linkage of three nationwide registers in Finland. Data collection included prescription drugs purchased during the preconception period and each trimester in the pregnant cohort, and the corresponding time periods in the non-pregnant controls. The pregnancy safety categorisation was determined for each drug (Anatomic Therapeutic Chemical [ATC] code) by using the Swedish classification of approved medicinal products (Farmaceutiska Specialiteter i Sverige [FASS]) and if not available, the corresponding Australian (Australian Drug Evaluation Committee [ADEC]) or US categorisation (FDA). GROUPS STUDIED: Women applying for maternity support (maternal grants) during the year 1999 (n = 43 470) plus non-pregnant control women matched by age and hospital district (n = 43 470).

RESULTS

In the pregnant cohort, 20.4% of women purchased at least one drug classified as potentially harmful during pregnancy, and 3.4% purchased at least one drug classified as clearly harmful. A significant decline occurred in the number of pregnant women purchasing potentially and clearly harmful drugs during the first trimester when compared with the preconception period, and the decline continued from the first to the second trimester. In the pregnant cohort, 107 (0.2%) women purchased at least ten different drugs during pregnancy. The drugs most commonly purchased in this group were topical corticosteroids and nasal preparations.

CONCLUSION

The use of hazardous prescription drugs declines during pregnancy but prescriptions of known teratogens and the relatively frequent practice of polypharmacy in epilepsy place emphasis on the need for careful pre-pregnancy counselling. However, drug safety classifications give a very crude estimation of risk and should only be used as general guidelines when planning treatment. Risk assessment must always be made on an individual basis, and pregnant women with illnesses requiring treatment must be treated adequately.