Fetal alcohol syndrome: a new primate model for binge drinking and its relevance to human ethanol teratogenesis

Parental factors predicting social deviance and psychological outcomes in offspring: Evidence from the Avon Longitudinal Study of Parents and Children (ALSPAC)

Objective: The objective of the present study was to examine whether exposure to prenatal psychoactive substances is associated with psychological outcomes and deviant behaviour. Methods: This was a secondary analysis of 7,769 mother-child dyads in the Avon Longitudinal Study of Parents and Children (ALSPAC) who were followed until the children were aged approximately 12 years. Parental characteristics and maternal use of various substances were collected in pregnancy and entered as predictors of psychological outcomes in childhood and deviant behaviours in early adolescence. The psychological outcomes were IQ, social cognition, working memory and inhibition, while the deviant behaviours were threatening others, truancy and cruelty to animals. Weighted logistic regression models were used to predict deviant behaviours and weighted linear regression for the psychological outcomes. Results: High prenatal alcohol exposure predicted truancy and cruelty to animals. Tobacco exposure predicted lower IQ, a greater social communication deficit, lower working memory, truancy and threatening others. Illicit drugs predicted a higher social communication deficit and truancy. All prenatal substance exposures remained significant after adjustment for peer influences and covariate imbalance. Conclusion: Alcohol, tobacco and illicit drugs were associated with deviant behaviours in early adolescence and these behaviours were preceded by psychological deficits in childhood. The present study supports the guideline that no amount of alcohol is safe to consume in pregnancy and that tobacco and illicit drugs should be avoided.

Fetal Alcohol Spectrum Disorder: The Honey Bee as a Social Animal Model

Animal models have been essential for advancing research of fetal alcohol spectrum disorder (FASD) in humans, but few animal species effectively replicate the behavioural and clinical signs of FASD. The honey bee (Apis mellifera) is a previously unexplored research model for FASD that offers the distinct benefit of highly social behaviour. In this study, we chronically exposed honey bee larvae to incremental concentrations of 0, 3, 6, and 10% ethanol in the larval diet using an in vitro rearing protocol and measured developmental time and survival to adult eclosion, as well as body weight and motor activity of newly emerged adult bees. Larvae reared on 6 and 10% dietary ethanol demonstrated significant, dose-responsive delays to pupation and decreased survival and adult body weight. All ethanol-reared adults showed significantly decreased motor activity. These results suggest that honey bees may be a suitable social animal model for future FASD research.

Aerobic Physical Training Attenuates Oxidative Stress in the Spinal Cord of Adult Rats Induced by Binge-like Ethanol Intake

Binge drinking is the most frequent consumption pattern among young adults and remarkably changes the central nervous system; thus, research on strategies to protect it is relevant. This study aimed to investigate the detrimental effects of binge-like EtOH intake on the spinal cord of male rats and the potential neuroprotective effects provided by moderate-intensity aerobic physical training. Male Wistar rats were distributed into the 'control group', 'training group', 'EtOH group', and 'training + EtOH'. The physical training protocol consisted of daily 30-min exercise on a treadmill for 5 consecutive days followed by 2 days off during 4 weeks. After the fifth day of each week, distilled water ('control group' and 'training group') or 3 g/kg of EtOH diluted at 20% w/v ('EtOH group' and 'training + EtOH group') was administered for 3 consecutive days through intragastric gavage to simulate compulsive consumption. Spinal cord samples were collected for oxidative biochemistry and morphometric analyses. The binge-like EtOH intake induced oxidative and tissue damage by decreasing reduced glutathione (GSH) levels, increasing lipid peroxidation (LPO), and reducing motor neurons (MN) density in the cervical segment. Even under EtOH exposure, physical training maintained GSH levels, reduced LPO, and prevented MN reduction at the cervical segment. Physical training is a non-pharmacological strategy to neuroprotect the spinal cord against oxidative damage induced by binge-like EtOH intake.

Toxicant and teratogenic effects of prenatal alcohol

Prenatal alcohol exposure can result in growth, cognitive, and behavioral deficits due to the toxicant and teratogenic effects of alcohol. Alcohol is an unusual toxicant, because, unlike other toxicants, it is consumed and has biological effects in the millimolar range. Cerebral cortical development is particularly vulnerable to both alcohol's acute and long-term reprogramming effects. Recent evidence suggests that neuroinflammation may be a persistent result of prenatal alcohol exposure and that modes of cellular communication capable of carrying miRNAs, such as extracellular vesicles, may be an integral part of long-term changes to cellular communication and inflammation following in utero alcohol exposure.

Detecting Neurodevelopmental Effects of Early-Gestation Ethanol Exposure: A Nonhuman Primate Model of Ethanol Drinking During Pregnancy

BACKGROUND

Gestational ethanol (EtOH) exposure is associated with multiple developmental abnormalities, collectively termed fetal alcohol spectrum disorder (FASD). While the majority of women abstain from EtOH following knowledge of pregnancy, one contributing factor to the high FASD prevalence is that pregnancy is not detected until 4 to 6 weeks. Thus, EtOH consumption continues during the initial stages of fetal development.

METHODS

An experimental protocol is described in which rhesus macaques self-administer 1.5 g/kg/d EtOH (or isocaloric maltose dextrin) prior to pregnancy and through the first 60 days of a 168-day gestation term. Menstrual cycles were monitored, including measurements of circulating estradiol and progesterone levels. The latency to consume 1.5 g/kg EtOH and blood EtOH concentration (BEC) was measured.

RESULTS

Twenty-eight fetuses (14 EtOH and 14 controls) were generated in this study. EtOH did not affect menstrual cycles or the probability of successful breeding. No EtOH-induced gross adverse effects on pregnancy were observed. Individual variability in latency to complete drinking translated into variability in BEC, measured 90 minutes following session start. Drinking latencies in controls and EtOH drinkers were longer in the second gestational month than in the first. All pregnancies reached the planned experimental time point of G85, G110, or G135, when in utero MRIs were performed, fetuses were delivered by caesarean section, and brains were evaluated with ex vivo procedures, including slice electrophysiology. Fetal tissues have been deposited to the Monkey Alcohol Tissue Research Resource.

CONCLUSIONS

This FASD model takes advantage of the similarities between humans and rhesus macaques in gestational length relative to brain development, as well as similarities in EtOH self-administration and metabolism. The daily 1.5 g/kg dose of EtOH through the first trimester does not influence pregnancy success rates. However, pregnancy influences drinking behavior during the second month of pregnancy. Future publications using this model will describe the effect of early-gestation EtOH exposure on anatomical and functional brain development at subsequent gestational ages.

Fetal alcohol spectrum disorders: Zebrafish in the analysis of the milder and more prevalent form of the disease

Fetal Alcohol Spectrum Disorders (FASD) represent a large unmet medical need. Exposure of the developing human embryo to alcohol can lead to life-long suffering. Despite the well documented deleterious effects of alcohol on the developing fetus, pregnant women continue to drink alcohol, and FASD remains the leading cause of preventable mental retardation and other behavioral abnormalities. Particularly prevalent are the milder forms of the disease cluster, representing children who do not show obvious physical signs and who may be undiagnosed or misdiagnosed. To develop treatment and diagnostic tools, researchers have turned to animal models. The zebrafish is becoming one of the leading biomedical research organisms that may facilitate discovery of the biological mechanisms underlying this disease and the identification of biomarkers that may be used for diagnosis. Here we review the latest advances of this field, mostly focussing on the discoveries made in our own laboratory and others with zebrafish employed to analyze the effects of moderate to low level of exposure to alcohol. We argue that the zebrafish represents unique advantages, and adding information obtained with this species to the mix of other animal models will significantly increase translational relevance of animal biomedical research for the analysis of human FASD.

Maternal alcohol exposure during mid-pregnancy dilates fetal cerebral arteries via endocannabinoid receptors

Prenatal alcohol exposure often results in fetal alcohol syndrome and fetal alcohol spectrum disorders. Mechanisms of fetal brain damage by alcohol remain unclear. We used baboons (Papio spp.) to study alcohol-driven changes in the fetal cerebral artery endocannabinoid system. Pregnant baboons were subjected to binge alcohol exposure via gastric infusion three times during a period equivalent to the second trimester of human pregnancy. A control group was infused with orange-flavored drink that was isocaloric to the alcohol-containing solution. Cesarean sections were performed at a time equivalent to the end of the second trimester of human pregnancy. Fetal cerebral arteries were harvested and subjected to in vitro pressurization followed by pharmacological profiling. During each alcohol-infusion episode, maternal blood alcohol concentrations (BAC) reached 80 mg/dL, that is, equivalent to the BAC considered legal intoxication in humans. Circulating anandamide (AEA) and 2-arachidonoylglycerol (2-AG) remained unchanged. Ultrasound studies on pregnant mothers revealed that fetal alcohol exposure decreased peak systolic blood velocity in middle cerebral arteries when compared to pre-alcohol levels. Moreover, ethanol-induced dilation was observed in fetal cerebral arteries pressurized in vitro. This dilation was abolished by the mixture of AM251 and AM630, which block cannabinoid receptors 1 and 2, respectively. In the presence of AM251, the cannabinoid receptor agonist AEA evoked a higher, concentration-dependent dilation of cerebral arteries from alcohol-exposed fetuses. The difference in AEA-induced cerebral artery dilation vanished in the presence of AM630. CB1 and CB2 receptor mRNA and protein levels were similar in cerebral arteries from alcohol-exposed and control-exposed fetuses. In summary, alcohol exposure dilates fetal cerebral arteries via endocannabinoid receptors and results in an increased function of CB2.

Safety assessment for ethanol-based topical antiseptic use by health care workers: Evaluation of developmental toxicity potential

Ethanol-based topical antiseptic hand rubs, commonly referred to as alcohol-based hand sanitizers (ABHS), are routinely used as the standard of care to reduce the presence of viable bacteria on the skin and are an important element of infection control procedures in the healthcare industry. There are no reported indications of safety concerns associated with the use of these products in the workplace. However, the prevalence of such alcohol-based products in healthcare facilities and safety questions raised by the U.S. FDA led us to assess the potential for developmental toxicity under relevant product-use scenarios. Estimates from a physiologically based pharmacokinetic modeling approach suggest that occupational use of alcohol-based topical antiseptics in the healthcare industry can generate low, detectable concentrations of ethanol in blood. This unintended systemic dose probably reflects contributions from both dermal absorption and inhalation of volatilized product. The resulting internal dose is low, even under hypothetical, worst case intensive use assumptions. A significant margin of exposure (MOE) exists compared to demonstrated effect levels for developmental toxicity under worst case use scenarios, and the MOE is even more significant for typical anticipated occupational use patterns. The estimated internal doses of ethanol from topical application of alcohol-based hand sanitizers are also in the range of those associated with consumption of non-alcoholic beverages (i.e., non-alcoholic beer, flavored water, and orange juice), which are considered safe for consumers. Additionally, the estimated internal doses associated with expected exposure scenarios are below or in the range of the expected internal doses associated with the current occupational exposure limit for ethanol set by the Occupational Safety and Health Administration. These results support the conclusion that there is no significant risk of developmental or reproductive toxicity from repeated occupational exposures and high frequency use of ABHSs or surgical scrubs. Overall, the data support the conclusion that alcohol-based hand sanitizer products are safe for their intended use in hand hygiene as a critical infection prevention strategy in healthcare settings.

A comparison of the different animal models of fetal alcohol spectrum disorders and their use in studying complex behaviors

Prenatal ethanol exposure (PNEE) has been linked to widespread impairments in brain structure and function. There are a number of animal models that are used to study the structural and functional deficits caused by PNEE, including, but not limited to invertebrates, fish, rodents, and non-human primates. Animal models enable a researcher to control important variables such as the route of ethanol administration, as well as the timing, frequency and amount of ethanol exposure. Each animal model and system of exposure has its place, depending on the research question being undertaken. In this review, we will examine the different routes of ethanol administration and the various animal models of fetal alcohol spectrum disorders (FASD) that are commonly used in research, emphasizing their strengths and limitations. We will also present an up-to-date summary on the effects of prenatal/neonatal ethanol exposure on behavior across the lifespan, focusing on learning and memory, olfaction, social, executive, and motor functions. Special emphasis will be placed where the various animal models best represent deficits observed in the human condition and offer a viable test bed to examine potential therapeutics for human beings with FASD.

The effects of prenatal alcohol exposure on behavior: rodent and primate studies

The use of alcohol by women during pregnancy is a continuing problem. In this review the behavioral effects of prenatal alcohol from animal models are described and related to studies of children and adults with FASD. Studies with monkeys and rodents show that prenatal alcohol exposure adversely affects neonatal orienting, attention and motor maturity, as well as activity level, executive function, response inhibition, and sensory processing later in life. The primate moderate dose behavioral findings fill an important gap between human correlational data and rodent mechanistic research. These animal findings are directly translatable to human findings. Moreover, primate studies that manipulated prenatal alcohol exposure and prenatal stress independently show that prenatal stress exacerbates prenatal alcohol-induced behavioral impairments, underscoring the need to consider stress-induced effects in fetal alcohol research. Studies in rodents and primates show long-term effects of prenatal and developmental alcohol exposure on dopamine system functioning, which could underpin the behavioral effects.

Ethanol and cognition: indirect effects, neurotoxicity and neuroprotection: a review

Ethanol affects cognition in a number of ways. Indirect effects include intoxication, withdrawal, brain trauma, central nervous system infection, hypoglycemia, hepatic failure, and Marchiafava-Bignami disease. Nutritional deficiency can cause pellagra and Wernicke-Korsakoff disorder. Additionally, ethanol is a direct neurotoxin and in sufficient dosage can cause lasting dementia. However, ethanol also has neuroprotectant properties and in low-to-moderate dosage reduces the risk of dementia, including Alzheimer type. In fetuses ethanol is teratogenic, and whether there exists a safe dose during pregnancy is uncertain and controversial.

Heparin binding epidermal growth factor-like growth factor reduces ethanol-induced apoptosis and differentiation in human embryonic stem cells

Alcohol affects approximately 1% (40,000) of new born infants each year and is the main preventable cause of mental retardation in the US. Ethanol alters cell signaling and promotes apoptosis and differentiation. Heparin-binding epidermal growth factor-like growth factor (HB-EGF), a member of the EGF family of growth factors, has been reported to prevent apoptosis and differentiation. We treated human embryonic stem cells (hESCs) with ethanol (20 mM) to reflect casual drinking, with and without HB-EGF to measure its ability to prevent ethanol-induced apoptosis and differentiation. Apoptosis was measured by DNA fragmentation (terminal dUTP nick-end labeling assays) and activated caspase-3, while differentiation was accessed by SSEA-1 and OCT-3/4; western blotting assessed MAPK signaling. HB-EGF reduced SSEA-1 and elevated OCT-3/4, while reducing the amount of activated caspase-3 and DNA fragmentation. Western blot analysis showed HB-EGF prevents ethanol from altering MAPK phosphorylation. This data suggests that ethanol-induced apoptosis was reduced by HB-EGF, while hESC pluripotency was maintained.

Measures of Alcohol Damagein vitroin the Pigtailed Macaque (Macaca nemestrina)

A non-human primate model for the fetal alcohol syndrome (FAS) has been developed in a pilot study on four pigtailed macaques (Macaca nemestrina) receiving ethanol once weekly from 40 days of gestation (2.5 g/kg for three moderate-dose monkeys and 4.1 g/kg for one high-dose monkey). Ethanol and acetaldehyde levels and indices of general health were monitored throughout pregnancy. One pregnancy ended in miscarriage. The three infants born at term were compared to control infants. The infant exposed to the higher ethanol dose showed phenotypic similarities to humans with FAS. Its brain was microcephalic and dysplastic; reflex, motor and cognitive development were retarded. One infant receiving the moderate dose had subtle brain abnormalities; it was hyperkinetic and showed developmental retardation on several behavioral measures. The other moderately dosed infant was normal. A larger study now in progress will comprise six groups of seven monkeys, each group being exposed to 0 (control), 0.3, 0.6, 1.2, 2.5 or 4.1 g/kg of ethanol once weekly throughout gestation. So far, 4.1 g/kg ethanol has been shown to be fetotoxic when given between 8 and 13 days of pregnancy.

Fetal alcohol syndrome and developing craniofacial and dental structures--a review

OBJECTIVES

Fetal alcohol syndrome (FAS) is a collection of signs and symptoms seen in children exposed to alcohol in the prenatal period. It is characterized mainly by a distinct pattern of craniofacial malformations, physical and mental retardation. However, with the increased incidence of FAS, there is a great variation in the clinical features of FAS.

DESIGN

Narrative review.

RESULTS

This review describes data from clinical and experimental studies, and in vitro models. Experimental studies have shown that alcohol has a direct toxic effect on the ectodermal and mesodermal cells of the developing embryo, particularly in the cells destined to give rise to dentofacial structures (i.e. cranial neural crest cells). Other effects, such as, abnormal pattern of cranial and mandibular growth and altered odontogenesis are described in detail. The exact mechanism by which alcohol induces its teratogenic effects remains still unknown. The possible mechanisms are outlined here, with an emphasis on the developing face and tooth. Possible future research directions and treatment strategies are also discussed.

CONCLUSION

Early identification of children affected by prenatal alcohol exposure leads to interventions, services, and improved outcomes. FAS can be prevented with the elimination of alcohol consumption during pregnancy. We need to provide education, target high-risk groups, and make this issue a high priority in terms of public health.

Prenatal Cord Clamping in Newborn Macaca nemestrina: A Model of Perinatal Asphyxia

Our objective was to establish a nonhuman primate model of perinatal asphyxia appropriate for preclinical evaluation of neuroprotective treatment strategies under conditions that closely resemble human neonatal emergencies, and to begin testing the safety and efficacy of erythropoietin neuroprotective treatment. Prior to delivery by hysterotomy, the umbilical cords of near term Macaca nemestrina (n = 8) were clamped for times ranging between 12 and 15 min. Animals received erythropoietin (5,000 U/kg/dose x 2 i.v., n = 3), or vehicle (n = 5) after resuscitation. We assessed physiologic parameters, continuous electroencephalogram, magnetic resonance imaging/spectroscopy, safety parameters and behavior. Animals were euthanized at 4 months of age. Mean birth weight was 507 +/- 62 g. Initial arterial pH ranged from 6.75 to 7.12, with base deficits of 17-25 mEq. Animals were flaccid at birth, with attenuated electroencephalograms, and seizures occurred in 3 of 8 animals. We demonstrated magnetic resonance imaging/spectroscopy changes consistent with hypoxia (elevated lactate levels were present in some animals), significant motor and behavioral abnormalities (particularly with 15 min of cord clamping), and evidence of gliosis at the time of death. We have established a reproducible model of moderate to severe perinatal hypoxic-ischemic injury in M. nemestrina newborns. This model, which combines structural, biochemical, and behavioral assessments over time can be used to assess the safety and efficacy of neuroprotective strategies.

Rapid induction of apoptosis in gastrulating mouse embryos by ethanol and its prevention by HB-EGF

BACKGROUND

Ethanol exposure during gastrulation and early neurulation induces apoptosis within certain embryonic cell populations, leading to craniofacial and neurological defects. There is currently little information about the initial kinetics of ethanol-induced apoptosis, and interest in the ability of endogenous survival factors to moderate apoptosis is growing. Ethanol alters intracellular signaling, leading to cell death in chick embryos, suggesting that apoptosis could occur rapidly and that signaling pathways activated by survival factors might reduce apoptosis.

METHODS

Pregnant mice were intubated with 1, 2, or 4 g/kg ethanol on day 7.5 of embryogenesis (E7.5) 1, 3, or 6, hours before harvesting gastrulation-stage embryos. Control animals received maltose/dextran. Blood alcohol concentrations (BAC) were determined by gas chromatography. E7.5 embryos isolated from untreated dams were cultured in vitro for 1 or 3 hr with 0 or 400 mg% ethanol and 0 or 5 nM heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF). Apoptosis was quantified using fluorescence microscopy to detect annexin V binding and DNA fragmentation [terminal deoxynucleotidyl transferase-mediated dUTP-X nick end labeling (TUNEL)] in whole-mount or sectioned embryos.

RESULTS

Both annexin V binding and TUNEL were elevated (p < 0.05) in embryos exposed in utero to 1 g/kg ethanol for 3 hours, increasing linearly with time and ethanol concentration. Apoptosis increased (p < 0.05) in all germ cell layers. Mice treated with 4 g/kg sustained BAC of 400 mg% for nearly 3 hours, significantly increasing apoptosis within the first hour. Cultured embryos exposed to 400 mg% ethanol displayed 2- to 3-fold more TUNEL than vehicle-treated embryos (p < 0.05); however, exogenous HB-EGF prevented apoptosis.

CONCLUSIONS

Ethanol rapidly produced apoptosis in gastrulation-stage embryos, consistent with induction by intracellular signaling. The ethanol-induced apoptotic pathway was blocked by the endogenous survival factor, HB-EGF. Differences in the expression of survival factors within individual embryos could be partly responsible for variations in the teratogenic effects of ethanol among offspring exposed prenatally.

A pilot study of alcohol exposure and pharmacokinetics in women with or without children with fetal alcohol syndrome

AIMS

To determine the alcohol exposure and pharmacokinetics of alcohol in a group of women who had given birth to children with FAS, compared with women who had not given birth to FAS children.

METHODS

10 women who had given birth to FAS children (FAS mothers) and 20 Controls were studied to determine how they metabolize alcohol in a single limited-access quasi-experimental session of voluntary consumption of alcohol. They had free choice in the consumption of any amount of their favourite beverage for approximately 2.5 h, but their drinking was terminated if the breath alcohol concentrations (BrAC) exceeded 150 mg%. BrACs was measured during ethanol consumption and for several hours after, for estimation of alcohol exposure and pharmacokinetics.

RESULTS

FAS mothers consumed significantly larger amounts of alcohol, and achieved significantly higher peak BrAC levels than Controls. The rate of decline of alcohol from the circulation (beta-60) showed a 2-fold variation across subjects but there was no significant difference between the two groups.

CONCLUSIONS

This study did not show any difference in alcohol pharmacokinetics in free-choice drinking by non-pregnant women, who either have given or have never given birth to FAS children. However, mothers of FAS children tend to consume more alcohol per session. Future studies in larger samples will be needed to confirm these findings and to examine drinking patterns and other factors that may increase the risk of FAS in children of women who drink alcohol during pregnancy.

Stage-dependent effects of ethanol on cranial neural crest cell development: partial basis for the phenotypic variations observed in fetal alcohol syndrome

Fetal alcohol syndrome (FAS) is characterized by growth retardation, mental deficiencies, and numerous craniofacial and neuronal anomalies; the type and severity of these defects may be related to the time and dose of maternal ethanol exposure. Ethanol administered during presomitic stages results in the typical FAS craniofacial phenotype and is accompanied by a loss of cranial neural crest cells (CNCCs) through ethanol-induced cell death. However, the stage-specific effects of ethanol on the CNCC population is unknown. We examined the effects of ethanol on CNCC populations by treating in ovo chick embryos with a single ethanol dose (0.43 mmol/egg) at various stages of CNCC development, and corresponding to the first 3-4 weeks of human gestation. Ethanol treatment induced cell death and reduced CNCC populations in patterns consistent with observed dysmorphologies of CNCC-derived cranial structures. The precise population affected was dependent on the timing of ethanol exposure. Treatment at gastrulation or neurulation induced cell death and losses of CNCC populations, particularly those in rostral positions, and resulted in more severe craniofacial defects. In contrast, treatment at early somitic stages (4-16 somites) induced cell death, primarily within caudal CNCC populations, but resulted in less severe craniofacial defects, suggesting an increased capacity for recovery. These results suggest that there are distinct developmental windows during which the CNCCs may be particularly susceptible to ethanol-induced cell death. We conclude that ethanol exposure seems to affect specific events adversely during neural crest development. The timing of embryonic ethanol exposure relative to CNCC development could account, in part, for the heterogenous craniofacial defects observed in FAS.

Maternal risk factors in fetal alcohol syndrome: provocative and permissive influences

We present an hypothesis integrating epidemiological, clinical case, and basic biomedical research to explain why only relatively few women who drink alcohol during pregnancy give birth to children with alcohol-related birth defects (ARBDs), in particular, Fetal Alcohol Syndrome (FAS). We argue that specific sociobehavioral risk factors, e.g., low socioeconomic status, are permissive for FAS in that they provide the context for increased vulnerability. We illustrate how these permissive factors are related to biological factors, e.g., decreased antioxidant status, which in conjunction with alcohol, provoke FAS/ARBDs in vulnerable fetuses. We propose an integrative heuristic model hypothesizing that these permissive and provocative factors increase the likelihood of FAS/ARBDs because they potentiate two related mechanisms of alcohol-induced teratogenesis, specifically, maternal/fetal hypoxia and free radical formation.

Optic nerve hypoplasia: comparative effects in children and rats exposed to alcohol during pregnancy

Children with the fetal alcohol syndrome often have ocular anomalies. These include abnormalities of the eyes and adnexa (strabismus, blepharoptosis, epicanthus), as well as intraocular defects (cataract, glaucoma, persistent hyperplastic primary vitreous, retinal and optic nerve anomalies). Based on the clinical results in an ophthalmological study of a group of Swedish children with the fetal alcohol syndrome, in which optic nerve hypoplasia was found in up to one-half of the group, an experimental study was designed in rats pre- and perinatally exposed to alcohol by means of a liquid diet. The optic nerve was seriously affected. Macroglial cells and optic axons were ultrastructurally damaged. The diameter of the optic nerve cross section, glial cell nuclear area, axonal diameter, and the total number of optic axons showed significantly lower values in the alcohol-exposed group than in the controls. In addition, the retina from the alcohol-exposed animals displayed significantly lower values of the retinal thickness and ganglion cell nuclear volume, as compared to the controls. Thus, rats exposed to alcohol in utero developed hypoplasia of the optic nerve similar to the findings in children born to alcoholic mothers. This strongly supports the hypothesis that prenatal alcohol exposure may adversely affect the development of the optic nerve.

Fluctuating odontometric asymmetry and maternal alcohol consumption

Fluctuating asymmetry was evaluated in the dental arcades of 112 children (60 male, 52 female) of alcoholic mothers. Only individuals who showed no signs of the fetal alcohol syndrome were included. When these results were compared with those of a control group of 120 normal children, the former group was found to be significantly more asymmetric. The present study showed that canines were the least asymmetric whilst lateral incisors showed the greatest levels of asymmetry. It is suggested that the elevated levels of fluctuating odontometric asymmetry in children of alcoholic mothers may be ascribed to prenatal stress, especially during the soft tissue stage of odontogenesis.

Pregnancy outcomes after weekly oral administration of ethanol during gestation in the pig-tailed macaque: comparing early gestational exposure to full gestational exposure

An oral dose of 1.8 g/kg ethanol given once per week throughout gestation to gravid pig-tailed macaques (Macaca nemestrina) has been established previously as teratogenic. This study was designed to use this nonhuman primate model to mimic a common problematic human circumstance in which women intermittently abuse alcohol into early pregnancy, realize that they are in fact pregnant, and then want to know the chance that the conceptus is harmed. In order to evaluate this situation, gravid macaques were assigned to one of four dosing cohorts. Animals were given the 1.8 gm/kg dose of ethanol once per week for the first 3, 6, or 24 weeks (full gestation) of pregnancy. Control animals received an isocaloric, isovolemic sucrose solution once per week for 24 weeks. The pregnancies were carefully monitored and the infants were comprehensively evaluated for the first 24 months of life. This paper describes the pregnancies while subsequent papers will describe the infants. Peak plasma ethanol levels ranged from 175 to 250 mg/dl. Weekly maternal exposure to this intoxicating dose of ethanol, starting early in pregnancy, did not influence risk of pregnancy failure during the first 30 days of gestation but appeared to be associated with an increased risk of abortion occurring between gestational days 30 and 160. Of the pregnancies that were successfully carried to full term, the potentially teratogenic dose of ethanol did not alter pregnancy outcome in any clinically significant way.

Holoprosencephaly in a fetal macaque (Macaca nemestrina) following weekly exposure to ethanol

Previous studies in rodents have indicated that the facial changes of fetal alcohol syndrome (FAS) closely resemble those of a mild form of holoprosencephaly. In order to examine this relationship in non-human primates, we evaluated a 133-day gestation macaque (Macaca nemestrina) with holoprosencephaly, median cleft lip and palate, and encephalocele. The mother had been given ethanol once per week (1.8 g/kg body weight) from weeks 2 to 19 postconception. Diagnosis of holoprosencephaly was made following ultrasound evaluation for polyhydramnios and delivery of the female fetus by caesarean section. Another fetus of identical age was delivered by caesarean section for use as a control. Both fetuses were studied by anthropometric, gross, radiographic, and histologic techniques. In the fetus exposed to alcohol, no extracranial anomalies were identified and the karyotype was normal. The brain was micrencephalic, with absent olfactory bulbs, tracts, optic nerves and chiasma, fused frontal lobes, and a single, dilated lateral ventricle; a parietooccipital encephalocele consisted of thin, dysplastic cortex bordering the ventricle; the cerebellum was dysplastic and superiorly displaced. Within the craniofacial complex, anophthalmia was bilateral; premaxillary components were absent, palatal shelves separate, the maxillae closeset, and the ethmoid bone small and deformed. Most of these defects are similar to those encountered in humans with holoprosencephaly and support the hypothesis of shared etiologic and pathogenetic relations between the facial anomalies of fetal alcohol syndrome and holoprosencephaly.

Ocular teratology

The principles of teratology are described, and animal models for research in abnormal ocular development and clinical studies of human teratogens are surveyed. A review is made of presumed ocular teratogenic agents: radiation; external environmental teratogens; maternal conditions such as infections, diabetes, and epilepsy; alcohol and drugs such as thalidomide, retinoic acid, and coumarin anticoagulants; and other agents, such as cigarettes.

Is there a fetal effect with low to moderate alcohol use before or during pregnancy?

STUDY OBJECTIVE

The aim was to investigate the effect of low or moderate alcohol consumption upon fetal outcome.

DESIGN

This was a prospective randomised cohort study with mother and infant follow-up sample stratified on level of maternal alcohol intake.

SETTING

A large maternity hospital in Western Australia.

PARTICIPANTS

2002 randomly selected pregnant women were recruited over a 3 year period for questionnaire survey (19 mothers refused participation). From 665 women in a stratified subsample selected on the basis of prepregnancy alcohol consumption, 605 newborns were available for study. INVESTIGATION AND MAIN RESULTS: All 2002 women completed a comprehensive questionnaire on demographic, lifestyle (including diet), health, and obstetric factors. Of the 665 mothers who were followed through pregnancy, 605 liveborns were available at birth for measurement and detailed clinical evaluation. Low to moderate prepregnancy maternal alcohol intake was not associated with any untoward effect upon weight, length, head circumference at birth, or clinical well-being as indicated by Apgar score, respiratory distress syndrome, and overall clinical state. Other factors, particularly nicotine, were of much greater importance.

CONCLUSIONS

This study fails to show any significant relationship between low to moderate prepregnancy maternal alcohol intake and newborn clinical status. The outcome suggests that cautionary advice to pregnant women warning that any alcohol taken during pregnancy is potentially harmful to the fetus is inaccurate and therefore probably counterproductive.

Neuroanatomic and neurochemical abnormalities in nonhuman primate infants exposed to weekly doses of ethanol during gestation

Ethanol was orally administered once per week to 54 gravid pigtailed macaques (Macaca nemestrina) in doses of 0.0, 0.3, 0.6, 1.2, 1.8, 2.5 or 4.1 gm/kg from the 1st week in gestation or in doses of 2.5, 3.3 or 4.1 gm/kg from the 5th week. Mean maternal peak plasma ethanol concentrations (MPPEC's) ranged from 24 +/- 6 mg/dl at the 0.3 g/kg dose to 549 +/- 71 mg/dl at the 4.1 g/kg dose. Thirty-three live born infants were assessed for abnormalities of physical and behavioral development. Ocular pathology, neuropathologic and neurochemical assessements were done on 31 animals at 6 months postnatal age. Microphthalmia was noted in three of the 26 animals exposed to ethanol. Retinal ganglion cell loss was significantly associated with intra-uterine ethanol exposure. Microphthalmia and retinal ganglion cell loss was observed in both the delayed and full-gestational exposed animals. No structural anomalies were found in the brains via gross inspection or light microscopy. Chemical abnormalities in the striatal nuclei were identified. Striatal dopamine concentrations increased with increasing MPPEC exposure (0-249 mg/dl) among animals exposed weekly to ethanol throughout gestation. Striatal dopamine concentrations decreased with increasing MPPEC exposure (260-540 mg/dl) among animals whose weekly exposure to ethanol was delayed until the 5th week of gestation. The same pattern of association was also noted between MPPEC and ultrastructural alterations in the caudate nucleus. The extent of ultrastructural alterations increased with increasing MPPEC among the full-gestational exposed animals and decreased with increasing MPPEC among the delayed-dose animals.

Cerebral cortical morphology and behavior in rats following acute prenatal ethanol exposure

Cerebral cortical morphology and early motor development were evaluated in offspring from ethanol-exposed mothers, pairfed control mothers and ad libitum control rats. Ethanol-exposed rats received a total dose of 18 g/kg of ethanol by intubation on gestational Days 14 and 15, a critical period of development of the cerebral cortex. Pairfed control mothers received isocaloric sucrose on gestational Days 14 and 15 and were pairfed to ethanol-exposed animals from gestational Day 12 through gestational Day 20. Ethanol-exposed offspring weighed significantly less than control offspring from postnatal Day 7 through postnatal Day 28. Ethanol-exposed offspring also showed significant delays in reflex suspension (time an animal maintained its grip on a crossbar) and continuous corridor (number of turns in 5 min). The thickness of the cerebral cortex of ethanol-exposed offspring was significantly different from ad libitum and pairfed control offspring on postnatal Day 1. However, only Layer V and total cortical thickness were affected in ethanol-exposed offspring on postnatal Day 28. The results of this study indicate that ethanol exposure during a critical period of development causes alterations in central nervous system development and developmental delays.

Morphometric analysis of developing rat cerebral cortex following acute prenatal ethanol exposure

Morphologic alterations of fetal rat cerebral cortex were quantified by morphometric analysis following acute ethanol exposure on Gestational Day 14, a critical period of development of cerebral cortex. Pregnant rats were intubated with a total dose of 9 g/kg of ethanol on Gestational Day 14. Maternal blood ethanol levels ranged from 51 to 202 mg% during the period of ethanol exposure. Fetal brains were examined on Gestational Day 15, 24 h after the last dose of ethanol. The acute morphologic changes associated with ethanol exposure include enlargement of subventricular zone nuclei, cortical swelling, and dilation of pial blood vessels over the affected cortex. In some fetuses, cortical swelling was accompanied by the protrusion into the lateral ventricles of cytoplasmic blebs of ventricular zone cells. It is concluded that maternal ethanol exposure during a critical period of brain development produces measurable morphologic changes in fetal rat cerebral cortex within 24 h after ethanol exposure.

Neuroendocrine consequences of alcohol abuse in women

Alcohol abuse and alcoholism are associated with a broad spectrum of reproductive system disorders. Amenorrhea, anovulation, luteal phase dysfunction, and ovarian pathology may occur in alcohol-dependent women and alcohol abusers. Luteal phase dysfunction, anovulation and persistent hyperprolactinemia have also been observed in social drinkers studied under clinical research ward conditions. The mechanisms underlying alcohol-related disruptions of the hypothalamic-pituitary-ovarian-adrenal axis are unknown. The reproductive consequences of alcohol abuse and alcoholism range from infertility and increased risk for spontaneous abortion to impaired fetal growth and development. Recent studies of alcohol's effects on pituitary gonadotropins and on gonadal, steroid and adrenal hormones in women are reviewed. Research on the acute effects of alcohol on opioid antagonist and synthetic LHRH-stimulated pituitary gonadotropins is summarized. The implications of alcohol's effects on reproductive hormones for impairment of fetal growth and development are discussed.

Prenatal brain malformations following acute ethanol exposure in the rat

Morphology of the cerebral cortex was studied in fetuses on gestational Day 21 following oral administration of several doses of ethanol (for total doses of 10, 15, or 18 g/kg) to pregnant rats on gestational Days 14 and 15, a critical period for the development of the cerebral cortex. All doses of ethanol were associated with a reduction in maternal weight gain, fetal body weight, and placental weight. Only the high dose of ethanol (total dose 18 g/kg) caused significant fetal cortical thinning. Acute exposure of pregnant rats to ethanol produced dose-dependent malformations of the cerebral cortex and hippocampus in fetuses. On gestational Day 21, the 18 g/kg group contained fetuses with severely disorganized cortical architecture, heterotopias of the cerebral cortex, pia and choroid plexus, and status verrucosus deformis. Fetuses from the 10 g/kg group had less severe malformations, such as disorganization of layers of cortical neurons and dentate granule cells while fetuses from the 15 g/kg group had a mixture of severe and minor malformations. This study demonstrates that acute ethanol exposure during a critical period of development in rats can result in brain malformations similar to those reported in human fetuses and neonates from alcoholic mothers.

Ovarian stimulation by exogenous gonadotrophins in fetal ethanol-exposed immature rats

Adult pregnant rats were given either an ad libitum liquid diet containing 5% ethanol, a pair fed liquid diet or an ad libitum diet of rat chow and water administered throughout pregnancy and during the nursing period. The female offspring received either pregnant mare's serum gonadotrophin (PMSG) or PMSG followed by human chorionic gonadotrophin (hCG) at 30 days of age. The ovaries of fetal ethanol-exposed animals responded greater to the exogenous gonadotrophins with enhanced ovarian weights, increased numbers of ova shed, greater numbers of corpora lutea and antral follicles, and higher serum progesterone levels than in animals exposed to the control diets during gestation.

Physical anomalies and developmental delays in nonhuman primate infants exposed to weekly doses of ethanol during gestation

Ethanol was orally administered once per week to 54 gravid pigtailed macaques (Macaca nemestrina) in doses of 0.0, 0.3, 0.6, 1.2, 1.8, 2.5 or 4.1 gm/kg from the 1st week in gestation or in doses of 2.5, 3.3, or 4.1 gm/kg from the 5th week. Mean maternal mean peak plasma ethanol concentrations (MPPEC) ranged from 24 +/- 6 mg/dl at the 0.3 gm/kg dose to 549 +/- 71 mg/dl at the 4.1 gm/kg dose. Thirty-three viable infants were followed from birth to 6 months of age and assessed for growth, health, congenital anomalies and developmental rate. Facial anomalies, growth deficiency, or central nervous system dysfunction were found in 57% of the alcohol-exposed animals. No animal showed all the features of the human fetal alcohol syndrome. Ten of the twelve animals (83%) with mean MPPEC above 140 mg/dl had evidence of a teratogenic impact. The animals with full gestational exposure to ethanol and mean MPPEC between 140 and 249 mg/dl had much more severe and consistent cognitive abnormalities than the animals with delayed gestational exposures, even though the latter were exposed to mean MPPEC between 260 and 540 mg/dl. Conclusions from this study included: 1) ethanol-related behavioral teratogenesis occurred without accompanying physical anomalies, 2) measurable teratogenic effects from weekly exposures occurred only at intoxicating doses of ethanol, and 3) early gestational exposure to ethanol appeared to be more damaging to cognitive function than later and considerably greater alcohol exposure.

Pregnancy outcomes after weekly oral administration of ethanol during gestation in the pig-tailed macaque (Macaca nemestrina)

Ethanol was orally administered once per week to gravid pig-tailed macaques (Macaca nemestrina) in doses of 0.3, 0.6, 1.2, 1.8, 2.5, 3.3, or 4.1 g/kg. A control group received a sucrose solution, isocaloric and isovolemic to the highest ethanol dose. Pregnancy was followed after 116 possible conceptions in 54 females. Peak plasma ethanol concentrations (PPECs) ranged from 24 +/- 6 mg/dl at the 0.3 g/kg dose to 549 +/- 71 mg/dl at the 4.1 g/kg dose. An increased rate of spontaneous abortion was related to ethanol exposure at and above 1.8 g/kg (mean PPEC = 205 mg/dl). Pregnancy failure in the first 30 days of gestation increased at doses above 2.5 g/kg. The effect on pregnancy outcome of weekly exposure to ethanol in this nonhuman primate is comparable to available data on humans. The methodology of this study represents an effective model for studying ethanol teratogenesis in a nonhuman primate.

Ethyl alcohol-induced cardiovascular malformations in the chick embryo

Chick embryos incubated for 72-80 hours were exposed to various volumes (0.20-0.40 m1/egg) of 50% ethyl alcohol. Examination of embryos at day 14 of incubation showed that higher doses of ethanol decreased the survival rate of embryos compared with control embryos. Three major categories of cardiovascular malformations were observed in this study: intracardiac anomalies characterized primarily by isolated ventricular septal defect, ventricular septal defect with overriding aorta, double outlet right ventricle or common aorticopulmonary trunk; aortic arch anomalies; and subclavian artery anomalies. Frequencies of embryos with intracardiac anomalies were equal to or greater than 64.8% in the six groups exposed to ethanol. Administration of ethanol also induced high frequencies of embryos with subclavian artery anomalies (11.2-89.1%). Absence or hypoplasia of the right and/or left secondary subclavian artery was commonly associated with persistence of the corresponding primary subclavian artery. Bilateral absence and/or hypoplasia of the secondary subclavian arteries was more common than unilateral anomalies, whereas absence of the left secondary subclavian artery was more commonly observed than an absent right secondary subclavian artery. No embryos in the two control groups combined (n = 94) demonstrated aortic arch or subclavian artery anomalies.

Teratogenic effects on the CD-1 mouse embryo exposed to concurrent doses of ethanol and aspirin

Human fetal alcohol syndrome characteristics have been seen in the mouse fetus by several investigators who dosed the dam with only one or two doses of alcohol. The purpose of this study was to determine if the fetal effects of acute doses of alcohol (ethanol) are altered by aspirin. CD-1 mice were given two IP doses of a 25% v/v solution of 95% ethanol/saline (2.5 hours apart) and intubated with 250 mg/kg aspirin. The treatment regimen, begun at 8 days, 4 hours gestation, consisted of either aspirin pretreatment 1 hour before or posttreatment 1 hour after the ethanol. Control animals were treated similarly and included vehicle only, ethanol/vehicle, and aspirin/vehicle groups. One group was untreated. On gestational day 18, the dams were killed and the uterine horns were examined for live, dead, and resorbed fetuses. The live were weighed and examined for external malformations and either skeletal or visceral abnormalities. With the litter as the unit of analysis, no significant difference was found in the number of dead and resorbed among groups. There was a significant difference (P less than .01) in average fetal weight in the aspirin-pretreated group. When the total number of fetuses affected was considered, the aspirin pretreatment group showed significantly (P less than .05) more external and visceral malformations. The skeletal examination revealed a significant (P less than .05) difference in anomalies plus delayed ossification in both groups treated with the aspirin/ethanol combination. No significant differences were seen in any category in the groups receiving aspirin alone or ethanol alone. These results indicate an additive effect of aspirin and ethanol on the developing CD-1 mouse fetus.

Postnatal or in utero ethanol exposure reduction of the volume of the sexually dimorphic nucleus of the preoptic area in male rats

Adult male rats exposed to alcohol in utero results in reduction of the volume of the sexually dimorphic nucleus of the preoptic area (SND-POA). Reduction of the volume of this nucleus is also significantly reduced in rats exposed to ethanol postnatally compared to the volume in animals not exposed to ethanol (P less than 0.05). The results indicate that ethanol exposure during the postnatal period of brain development in rats is equally effective as in utero ethanol exposure in development of the SDN-POA volume. This report substantiates others demonstrating the deleterious effects of ethanol consumption during the 'critical' period of brain development.

Alcohol-metabolizing enzymes in placenta and fetal liver: effect of chronic ethanol intake

Alcohol dehydrogenase and different subcellular distribution of aldehyde dehydrogenase (ALDH) in fetal liver and placenta at 15 and 21 days of gestation were studied in three different groups of pregnant rats: alcoholic, pair-fed, and rat solid chow diet animals. Chronic ethanol intake during pregnancy produced a decrease in fetal body and liver weight but an increase of placenta weight. No alcohol dehydrogenase was detected in placenta at any stage of gestation, nor in fetal liver at 15 days although a low activity was found at 21 days. No significant difference was observed from fetuses of alcoholic and nonalcoholic mothers. Subcellular aldehyde dehydrogenase distribution in placenta was similar to that in adult liver. Although no cytosolic ALDH was detected in fetal liver at any period of gestation, low activities were found in placenta and fetal liver at 15 days of pregnancy in other subcellular fractions. However, at 21 days the placental activity decreased while that of fetal liver increased markedly. The increase of the fetal liver ALDH was especially noticeable in the mitochondrial fraction in which the activity was approximately 10-fold higher than in the placenta mitochondrial fraction. A small decrease in placenta and fetal liver ALDH was observed in alcoholic rats. The role of the placenta ALDH in the acetaldehyde placental transfer is discussed.

Lactational ethanol exposure: brain enzymes and [3H]spiroperidol binding

Long-Evans lactating rats were fed 27% calories as ethanol in a liquid diet to determine whether alcohol received through the milk would alter normal brain development in the offspring. On days 16, 21 and 30, brains of the female offspring were removed, corpus striatum dissected and assayed for choline acetyltransferase activity, glutamic acid decarboxylase activity and [3H]spiroperidol binding activity. At day 16, there were no differences among the three treatment groups for the enzyme activities assayed. At day 21, glutamic acid decarboxylase activity in the pairfed group was higher than in ET and CT groups. Choline acetyltransferase activity in PF group was higher when compared to ad libitum controls and [3H]spiroperidol binding was not affected. At 30 days of age, animals exposed to ethanol had higher choline acetyltransferase activity and [3H]spiroperidol binding activity when compared to pairfed and ad libitum controls; and higher glutamic acid decarboxylase activity when compared to ad libitum controls. Data from the present study suggest that ethanol exposure during the brain growth spurt has a toxic effect on the late development of dopaminergic, cholinergic and GABAergic systems in the corpus striatum. These results may be related to the clinical symptoms of hyperactivity and problems with motor control in children exposed to alcohol during the third trimester and during lactation.

Ethanol neurotoxicity: effects on neurite formation and neurotrophic factor production in vitro

The effects of ethanol on chick embryo sensory and spinal cord neurons growing on one of several biological substrates (poly-D-lysine, laminin, or neuron-produced neurite-promoting materials) were examined. Ethanol inhibited process formation by the neurons in a dose-dependent manner and inhibited the production of neurotrophic factors. Neuronal attachment to the substrates, survival of attached neurons, and receptor interactions of sensory neurons with nerve growth factor were not influenced by ethanol. It appears that ethanol alters certain metabolic characteristics of developing neurons.

Glucose tolerance and insulin response in offspring of ethanol-treated pregnant rats

The effects of maternal alcohol ingestion on oral glucose tolerance and insulin response were studied just after birth and in 3-day old offspring of rats given ethanol for drinking (25% w/v) during pregnancy. Offspring litter size, litter survival and body weight were reduced as a consequence of maternal alcohol treatment. Basal plasma insulin levels were augmented in pups from alcoholized mothers just after birth, despite the fact that blood glucose did not change. Maternal alcohol consumption caused glucose intolerance associated with unchanged insulin response in pups just after birth whereas 3-day old pups from alcoholized mothers showed normal glucose tolerance associated with increased insulin response. Data indicate that chronic maternal ethanol treatment may cause impaired insulin sensitivity in the offspring.