Fetal Alcohol Effects Research Articles

Brain Volume in Fetal Alcohol Spectrum Disorders Over a 20-Year Span

Anomalous brain development and mental health problems are prevalent in fetal alcohol spectrum disorders (FASD), but there is a paucity of longitudinal brain imaging research into adulthood. This study presents long-term follow-up of brain volumetrics in a cohort of participants with FASD. To test whether brain tissue declines faster with aging in individuals with FASD compared with control participants. This cohort study used magnetic resonance imaging (MRI) data collected from individuals with FASD and control individuals (age 13-37 years at first magnetic resonance imaging [MRI1] acquired 1997-2000) compared with data collected 20 years later (MRI2; 2018-2021). Participants were recruited for MRI1 through the University of Washington Fetal Alcohol Syndrome (FAS) Follow-Up Study. For MRI2, former participants were recruited by the University of Washington Fetal Alcohol and Drug Unit. Data were analyzed from October 2022 to August 2023. Intracranial volume (ICV) and regional cortical and cerebellar gray matter, white matter, and cerebrospinal fluid volumes were quantified automatically and analyzed, with group and sex as between-participant factors and age as a within-participant variable. Of 174 individuals with MRI1 data, 48 refused participation, 36 were unavailable, and 24 could not be located. The remaining 66 individuals (37.9%) were rescanned for MRI2, including 26 controls, 18 individuals with nondysmorphic heavily exposed fetal alcohol effects (FAE; diagnosed prior to MRI1), and 22 individuals with FAS. Mean (SD) age was 22.9 (5.6) years at MRI1 and 44.7 (6.5) years at MRI2, and 35 participants (53%) were male. The FAE and FAS groups exhibited enduring stepped volume deficits at MRI1 and MRI2; volumes among control participants were greater than among participants with FAE, which were greater than volumes among participants with FAS (eg, mean [SD] ICV: control, 1462.3 [119.3] cc at MRI1 and 1465.4 [129.4] cc at MRI2; FAE, 1375.6 [134.1] cc at MRI1 and 1371.7 [120.3] cc at MRI2; FAS, 1297.3 [163.0] cc at MRI1 and 1292.7 [172.1] cc at MRI2), without diagnosis-by-age interactions. Despite these persistent volume deficits, the FAE participants and FAS participants showed patterns of neurodevelopment within reference ranges: increase in white matter and decrease in gray matter of the cortex and decrease in white matter and increase in gray matter of the cerebellum. The findings of this cohort study support a nonaccelerating enduring, brain structural dysmorphic spectrum following prenatal alcohol exposure and a diagnostic distinction based on the degree of dysmorphia. FASD was not a progressive brain structural disorder by middle age, but whether accelerated decline occurs in later years remains to be determined.

Graded regional cerebellar volume deficits in adolescents and adults with Fetal Alcohol Effect (FAE) and Fetal Alcohol Syndrome (FAS)

Graded regional cerebellar volume deficits in adolescents and adults with Fetal Alcohol Effect (FAE) and Fetal Alcohol Syndrome (FAS)

Transgenerational inheritance of fetal alcohol effects on proopiomelanocortin gene expression and methylation, cortisol response to stress, and anxiety-like behaviors in offspring for three generations in rats: Evidence for male germline transmission.

Previously it has been shown that fetal alcohol exposure increases the stress response partly due to lowering stress regulatory proopiomelanocortin (Pomc) gene expression in the hypothalamus via epigenetic mechanisms for multiple generations in mixed-breed rats. In this study we assess the induction of heritable epigenetic changes of Pomc-related variants by fetal alcohol exposure in isogenic Fischer 344 rats. Using transgenerational breeding models and fetal alcohol exposure procedures, we determined changes in hypothalamic Pomc gene expression and its methylation levels, plasma corticosterone hormone response to restraint stress, and anxiety-like behaviors using elevated plus maze tests in fetal alcohol-exposed offspring for multiple generations in isogenic Fischer rats. Fetal alcohol-exposed male and female rat offspring showed significant deficits in POMC neuronal functions with increased Pomc gene methylation and reduced expression. These changes in POMC neuronal functions were associated with increased plasma corticosterone response to restraint stress and increased anxiety-like behavior. These effects of fetal alcohol exposure persisted in the F1, F2, and F3 progeny of the male germline but not of the female germline. These data suggest that fetal alcohol exposure induces heritable changes in Pomc-related variants involving stress hyperresponsiveness and anxiety-like behaviors which perpetuate into subsequent generations through the male germline via epigenetic modifications.

Prenatal alcohol exposure and mental health at midlife: A preliminary report on two longitudinal cohorts.

Although the effects of prenatal alcohol exposure (PAE) have been studied extensively, there is relatively little information available on adult mental health functioning among exposed individuals. The current study compares the self-reported midlife mental health status of individuals who were prenatally exposed to alcohol and diagnosed in childhood with the effects of this exposure with that of unexposed individuals. Participants (N=292) were recruited from two longitudinal cohorts in Atlanta and Seattle and asked to complete an Adult Health Questionnaire that surveyed their current health and mental health status. The questionnaire was completed either in-person or remotely and included questions about current symptoms of depression and anxiety and mental health disorder diagnoses. The analysis compared a Nonexposed Contrast group to those in two exposure groups: (1) Alcohol Exposed with Fetal Alcohol Effect but not meeting criteria for Fetal Alcohol Syndrome (FAS) and (2) Alcohol Affected and meeting criteria for FAS. Both alcohol-exposed groups reported higher levels of current depressive symptoms and a higher prevalence of diagnoses of depression, anxiety, bipolar disorder, and/or attention deficit/hyperactivity disorder. No differences were noted for psychotic disorders. PAE was also associated with greater environmental stressors, including higher levels of adverse childhood events and lower current socioeconomic status. Path analyses suggested that PAE was indirectly related to mood disorders with its effects being mediated by other environmental factors. PAE is associated with greater rates of mental health disorders in middle adulthood. These outcomes appear to result from multiple stressors that affect individuals made vulnerable by their early alcohol exposure. Clinical outcomes could be improved by prevention efforts directed at preventing prenatal alcohol use and reducing environmental stressors later in life, and by the early identification of PAE and its effects.

A-40 The Neurocognitive and Behavioral Profile of an Adolescent with in-Utero Exposure to Alcohol

Abstract Objective Prenatal alcohol exposure can result in altered brain development that has detrimental effects on children and put them at increased risk for cognitive impairment, sensorimotor deficits, attention problems, behavioral issues, and social–emotional difficulties. Further, adolescents with neurodevelopmental disorders associated with in-utero exposure to alcohol require targeted academic and psychosocial support as they transition into adulthood which emphasizes the need for neuropsychological assessment. Method This case study presents on the neuropsychological profile of a 17-year-old male in the 11th grade who was exposed to alcohol in-utero and was diagnosed with fetal alcohol effects as a young child by his primary care physician. Results Neuropsychological testing revealed a broad range of impairments which included deficits in intellectual functioning (mild disability), adaptive functioning, language, academic achievement, attention, executive functioning, memory, fine/visuomotor skills, and social–emotional functioning. Conclusions Recommendations were made to modify his special education goals by targeting his functional academic skills, adaptive functioning, communication skills, and post-high school transition planning. Recommendations for behavioral interventions were given to his referring psychotherapist to aid in treatment planning. Information on vocational counseling and financial support for individuals with developmental disabilities were provided to the patient’s guardian as well. This case study illustrates the long-lasting neurocognitive and behavioral effects associated with in-utero alcohol exposure and the need for neuropsychological assessment during adolescence in order to reduce secondary issues (e.g., school problems, lack of mental health support, unemployment, and financial hardship) that can occur as these individuals move into adulthood.

International Adoption: A Review and Update.

1. Judith Kim Eckerle, MD*,† 2. Megan Marie Bresnahan, OTR/L† 3. Maria Kroupina, PhD, LP*,† 4. Dana Ernest Johnson, MD, PhD*,† 5. Cynthia Ruth Howard, MD, MPHTM*,† 1. *Department of Pediatrics, University of Minnesota, Minneapolis, MN 2. †MHealth Fairview University of Minnesota Masonic Children’s Hospital, Minneapolis, MN * Abbreviations: Ab : : antibody ACE : : adverse childhood experience CDC : : Centers for Disease Control and Prevention CXR : : chest radiography IA : : international adoptee TB : : tuberculosis 1. Key information for accurate assessment of the preadoption referral. 2. Determining immunization status and planning catch-up strategy. 3. Updated screening protocol for and treatment of latent tuberculosis infection. 4. Evaluation of developmental delays in the context of international adoption. 5. Screening for risk factors indicating the need for referral to child mental health and developmental specialists. After completing this article, readers should be able to: 1. Review the basic components of an adoption referral file and know when to consult an international adoption medicine expert. 2. Perform the initial medical assessment of a newly arrived international adoptee, including evaluation of the efficacy of previous immunizations and planning of catch-up immunization based on new recommendations. 3. Screen for tuberculosis and treat latent tuberculosis infection based on recent Centers for Disease Control and Prevention (CDC) guidelines. 4. Understand the multiple areas of a developmental baseline of adopted children and assess for catch-up needs. 5. Identify the child with multiple risk factors and/or parental or family stressors who needs a referral to an adoption-competent mental health specialist. Although interest in intercountry adoption continues to be high, the numbers of international adoptions have changed dramatically since the peak in 2004 when 45,483 international adoptees (IAs) were placed in families worldwide. By 2017, the number dropped 79% to 9,387. In the United …

Sex-Determining Region Y Controls the Effects of Fetal Alcohol Exposure on Proopiomelanocortin Gene Expression.

Fetal alcohol exposure (FAE) causes various neurodevelopmental deficits in offspring, including reduced expression of the stress regulatory proopiomelanocortin (Pomc) gene and an elevated stress response for multiple generations via the male germline. Male germline-specific effects of FAE on the Pomc gene raises the question if the sex-determining region Y (SRY) may have a role in regulating Pomc gene expression. Using a transgenerational model of FAE in Fischer 344 rats, we determined the role of SRY in the regulation of the Pomc gene. FAEs, like on the Pomc gene, reduced Sry gene expression in sperm and the mediobasal hypothalamus (MBH) in male adult offspring. Fetal alcohol-induced inhibition of Sry gene expression was associated with increased Sry promoter DNA methylation. Additionally, fetal alcohol effects on the Sry gene persisted for three generations in the male germline but not in the female germline. Sry gene knockdown reduced the Pomc gene expression. Sry recruitment onto the Pomc promoter was found to be reduced in the hypothalamus of fetal alcohol-exposed rats compared to control rats. Pomc promoter luciferase activity was increased following Sry overexpression. A site-directed mutagenesis study revealed that SRY binding sites are required for POMC promoter transcription activity. Overall, these findings suggest that SRY plays a stimulatory role in the regulation of Pomc gene expression and may potentially contribute to the fetal alcohol-induced changes in the level of Pomc gene expression for multiple generations.

Fatty acid ethyl esters in meconium: A biomarker of fetal alcohol exposure and effect.

To determine if meconium fatty acid ethyl esters (FAEE) in rat pups is a good biomarker of prenatal exposure and effect to alcohol, three groups of pregnant rats were studied: one control (pair fed) and two treatment groups given 25% alcohol at 2.2 or 5.5 g-1 kg-1 d-1. The pups were delivered on day 20 and, for each dam, were separated into a male and female group. The body, brain, intestines, and placenta of the pups were obtained, weighed, and stored at -20°C. The pups' intestines (as surrogate of meconium) from each group were pooled, and meconium was analyzed by gas chromatography/mass spectroscopy for FAEE. The meconium showed the following FAEE: ethyl palmitate, ethyl stearate, and ethyl linolenate and were only found in the alcohol-treated group and with high specificity but low sensitivity. Mean body weight of the pups was lower in the treatment groups compared to the control groups. Ethyl palmitate concentration correlated negatively to the pups' mean body and brain weights. Therefore, ethyl palmitate, stearate, and linolenate, in meconium of rat pups prenatally exposed to alcohol, are useful biomarkers of prenatal alcohol exposure, with ethyl palmitate a good biomarker of adverse effect on the pups' body and brain weight.

Graded Cerebellar Lobular Volume Deficits in Adolescents and Young Adults with Fetal Alcohol Spectrum Disorders (FASD).

The extensive prenatal developmental growth period of the cerebellum renders it vulnerable to unhealthy environmental agents, especially alcohol. Fetal alcohol spectrum disorders (FASD) is marked by neurodysmorphology including cerebral and cerebellar volume deficits, but the cerebellar lobular deficit profile has not been delineated. Legacy MRI data of 115 affected and 59 unaffected adolescents and young adults were analyzed for lobular gray matter volume and revealed graded deficits supporting a spectrum of severity. Graded deficits were salient in intracranial volume (ICV), where the fetal alcohol syndrome (FAS) group was smaller than the fetal alcohol effects (FAE) group, which was smaller than the controls. Adjusting for ICV, volume deficits were present in VIIB and VIIIA of the FAE group and were more widespread in FAS and included lobules I, II, IV, V, VI, Crus II, VIIB, and VIIIA. Graded deficits (FAS < FAE) were consistently present in lobules VI; neither group showed volume deficits in Crus I or IX. Neuroradiological readings blind to diagnosis identified 20 anomalies, 8 involving the cerebellum, 5 of which were in the FAS group. We speculate that the regional cerebellar FASD-related volume deficits may contribute to diagnostically characteristic functional impairment involving emotional control, visuomotor coordination, and postural stability.

Corrigendum: Graded Cerebellar Lobular Volume Deficits in Adolescents and Young Adults with Fetal Alcohol Spectrum Disorders (FASD).

The extensive prenatal developmental growth period of the cerebellum renders it vulnerable to unhealthy environmental agents, especially alcohol. Fetal alcohol spectrum disorders (FASD) is marked by neurodysmorphology including cerebral and cerebellar volume deficits, but the cerebellar lobular deficit profile has not been delineated. Legacy MRI data of 115 affected and 59 unaffected adolescents and young adults were analyzed for lobular gray matter volume and revealed graded deficits supporting a spectrum of severity. Graded deficits were salient in intracranial volume (ICV), where the fetal alcohol syndrome (FAS) group was smaller than the fetal alcohol effects (FAE) group, which was smaller than the controls. Adjusting for ICV, volume deficits were present in VIIB and VIIIA of the FAE group and were more widespread in FAS and included lobules I, II, IV, V, VI, Crus II, VIIB, and VIIIA. Graded deficits (FAS < FAE) were consistently present in lobules VI; neither group showed volume deficits in Crus I or IX. Neuroradiological readings blind to diagnosis identified 20 anomalies, 8 involving the cerebellum, 5 of which were in the FAS group. We speculate that the regional cerebellar FASD-related volume deficits may contribute to diagnostically characteristic functional impairment involving emotional control, visuomotor coordination, and postural stability.

Drinking during pregnancy: Potential role of endocannabinoid signaling in fetal alcohol effects

Drinking during pregnancy: Potential role of endocannabinoid signaling in fetal alcohol effects

Dietary choline levels modify the effects of prenatal alcohol exposure in rats

Prenatal alcohol exposure can cause a range of physical and behavioral alterations; however, the outcome among children exposed to alcohol during pregnancy varies widely. Some of this variation may be due to nutritional factors. Indeed, higher rates of fetal alcohol spectrum disorders (FASD) are observed in countries where malnutrition is prevalent. Epidemiological studies have shown that many pregnant women throughout the world may not be consuming adequate levels of choline, an essential nutrient critical for brain development, and a methyl donor. In this study, we examined the influence of dietary choline deficiency on the severity of fetal alcohol effects. Pregnant Sprague-Dawley rats were randomly assigned to receive diets containing 40, 70, or 100% recommended choline levels. A group from each diet condition was exposed to ethanol (6.0g/kg/day) from gestational day 5 to 20 via intubation. Pair-fed and ad lib lab chow control groups were also included. Physical and behavioral development was measured in the offspring. Prenatal alcohol exposure delayed motor development, and 40% choline altered performance on the cliff avoidance task, independent of one another. However, the combination of low choline and prenatal alcohol produced the most severe impairments in development. Subjects exposed to ethanol and fed the 40% choline diet exhibited delayed eye openings, significantly fewer successes in hindlimb coordination, and were significantly overactive compared to all other groups. These data suggest that suboptimal intake of a single nutrient can exacerbate some of ethanol's teratogenic effects, a finding with important implications for the prevention of FASD.

Modeling Symptoms of Attention-Deficit Hyperactivity Disorder in a Rat Model of Fetal Alcohol Syndrome.

Several studies indicate the similarity between the symptoms of fetal alcohol syndrome and attention-deficit hyperactivity disorder (ADHD). This study hypothesized that prenatal exposure to ethanol (EtOH) can be used as an animal model of ADHD in Wistar rats. At the first stage of the study, alcohol was delivered to the pregnant dams (237-252 g) by intra-gastric route throughout Gestation Days 8-20 at a dose of 6 g/kg/day. Untreated control group with isocaloric sucrose intubation was also included. Of the 16 male pups (174-180 g), 8 were in the fetal alcohol effects (FAE) group and 8 were in the untreated control group. Subjects went through behavior shaping, discrimination learning and reversal learning. Number of sessions to learn the tasks, response frequency to inhibitory (S-) and excitatory (S+) stimulus features, response latency and inter-response time (IRT) were measured. Significant differences were obtained on only the reversal task. Rats with FAE needed greater number of sessions to learn the reversal task, and they had a higher frequency of incorrect responses in specifically the latter part of the sessions. Our results suggest that reversal learning of FAE rats exhibits deficit in the inhibition of pre-learned responses. Responses behaviorally mimicked attention deficit and impulsivity symptoms of human ADHD. However, the experimental design of the study was not conducive to hyperactivity. Accordingly, rats with FEA can be an alternative to other models since it is not, for example, based on a symptom that is atypical (such as hypertension) to ADHD. Significant difference was obtained in a reversal task between male rats prenatally exposed to ethanol and matched controls. The greater number of sessions for learning and higher frequency of incorrect responses behaviorally mimicked symptoms of ADHD, suggesting that rats with fetal ethanol effects can serve as a useful animal model.

Adolescent Choline Supplementation Attenuates Working Memory Deficits in Rats Exposed to Alcohol During the Third Trimester Equivalent.

Children exposed to alcohol prenatally may suffer from behavioral and cognitive alterations that adversely affect their quality of life. Animal studies have shown that perinatal supplementation with the nutrient choline can attenuate ethanol's adverse effects on development; however, it is not clear how late in development choline can be administered and still effectively reduce the consequences of prenatal alcohol exposure. Using a rodent model, this study examined whether choline supplementation is effective in mitigating alcohol's teratogenic effects when administered during adolescence/young adulthood. Sprague-Dawley rats were exposed to alcohol (5.25 g/kg/d) during the third trimester equivalent brain growth spurt, which occurs from postnatal day (PD) 4 to 9, via oral intubation. Sham-intubated and nontreated controls were included. Subjects were treated with 100 mg/kg/d choline chloride or vehicle from PD 40 to 60, a period equivalent to young adulthood in the rat. After the choline treatment had ceased, subjects were tested on a series of behavioral tasks: open field activity (PD 61 to 64), Morris water maze spatial learning (PD 65 to 73), and spatial working memory (PD 87 to 91). Ethanol-exposed subjects were overactive in the activity chambers and impaired on both the spatial and the working memory versions of the Morris water maze. Choline treatment failed to attenuate alcohol-related overactivity in the open field and deficits in Morris water maze performance. In contrast, choline supplementation significantly mitigated alcohol-related deficits in working memory, which may suggest that choline administration at this later developmental time affects functioning of the prefrontal cortex. The results indicate that adolescent choline supplementation can attenuate some, but not all, of the behavioral deficits associated with early developmental alcohol exposure. The results of this study indicate that dietary intervention may reduce some fetal alcohol effects, even when administered later in life, findings with important implications for adolescents and young adults with fetal alcohol spectrum disorders.

Prenatal Alcohol Exposure May Be Driving Some Violent Behavior

Back to table of contents Previous article Next article Professional NewsFull AccessPrenatal Alcohol Exposure May Be Driving Some Violent BehaviorAaron LevinAaron LevinSearch for more papers by this authorPublished Online:24 Mar 2016https://doi.org/10.1176/appi.pn.2016.4a6AbstractNeurodevelopmental disorders associated with prenatal alcohol exposure may lead to poor judgment and affect regulation, and in some cases violence, according to Carl Bell, M.D.The mass shootings that leap to public attention mask a larger, ongoing epidemic of day-to-day killings and gun violence, Carl Bell, M.D., a staff psychiatrist at Jackson Park Hospital in Chicago, told an audience gathered for the Washington Psychiatric Society’s Presidential Symposium on Violence Risk Reduction at St. Elizabeths Hospital in February.“Fetal alcohol exposure is a hidden epidemic in poor African-American communities,” comments Chicago psychiatrist Carl Bell, M.D. An easily available supplement has shown evidence of ameliorating symptoms, he said.Milbert O. Brown“The existing evidence regarding the incidence of urban gun homicide flies in the face of conventional media analysis and public beliefs, which tend to focus attention on the sensational,” Bell said. “The causes of urban youth gun violence are multidetermined and extraordinarily complex, so a multipronged strategy is likely to get the best results.”One focus of that strategy, Bell proposes, should be on decreasing the effects of fetal alcohol exposure—a factor he believes may be contributing to the violence on America’s streets.“Recent data indicate that a large proportion of urban children of color in special education, juvenile justice, foster care, and mental health clinics have histories of neurodevelopmental disorders—most likely due to fetal alcohol exposure,” he said. These children have poor judgment and affect regulation and are easily frustrated, and at least some become violent.The effects of alcohol on the etiology of violent behavior have likely been underestimated, asserted Bell. Up to half of the women who receive services at the hospital where Bell works don’t know when they are in the earliest stages of pregnancy and continue using alcohol, he said. “If you ask them, they’ll say they stopped drinking when they became pregnant, but what they mean is they stopped when they knew they were pregnant.”Bell has conducted several studies whose results suggest that roughly one-third of patients in Chicago’s poor communities may have a neurodevelopmental disorder associated with prenatal alcohol exposure. “Fetal alcohol exposure is a hidden epidemic in poor African-American communities ... ,” he wrote in the May 2014 issue of Psychiatric Services.Managing fetal alcohol exposure and its consequences is not hopeless, said Bell. Recent research has pointed to the value of phosphatidylcholine supplementation both for pregnant women and their children. A recent study in the American Journal of Psychiatry reported that high-dose oral phosphatidylcholine taken during pregnancy resulted in fewer attention problems and less social withdrawal in offspring.Researchers suspect the α7-nicotinic acetylcholine receptor gene CHRNA7, which “has been associated with schizophrenia, autism, and attention-deficit/hyperactivity disorder,” may play a role in this response, wrote Randal Ross, M.D., a professor of psychiatry and pediatrics at the University of Colorado School of Medicine, Aurora, and colleagues in the article posted online December 7, 2015. “Maternal phosphatidylcholine treatment may, by increasing activation of the α7-nicotinic acetylcholine receptor, alter the development of behavior problems in early childhood that can presage later mental illness,” the authors wrote.“Choline supplementation can alter brain development following a developmental insult, and similar postnatal interventions may reduce the severity of some fetal alcohol effects,” said Bell. Other researchers have found that treating children aged 2.5 to 5 years with a nine-month course of choline improved scores on memory tests.Behavioral interventions have also proved useful, he said. Developing a community’s social fabric, encouraging adults to mentor youth, and offering programs to build social and emotional skills have proven to decrease risk-taking behaviors and youth gun violence.Too often, attempts to solve the problem have focused solely on risk factors and how to ameliorate them, said Bell.“But we must be smart enough to wrap at-risk youth in protective factors,” he said. “Public health interventions that focus on the protective factors that prevent the risk factors from becoming predictive factors are the recommended approaches.” ■“Perinatal Phosphatidylcholine Supplementation and Early Childhood Behavior Problems: Evidence for CHRNA7 Moderation” can be accessed here. “Fetal Alcohol Exposure Among African Americans” is available here. ISSUES NewArchived

Animal Models for Medication Development and Application to Treat Fetal Alcohol Effects.

Ethanol consumption during pregnancy can have lifelong consequences for the offspring, their family and society. Fetal alcohol spectrum disorders (FASD) include a range of physical and behavioral effects with the most significant impact occurring as a result of the effects of ethanol on the developing central nervous system (CNS). To date, there are no FDA approved drugs that have been tested that prevent/reduce or specifically treat the symptoms of FASD. There are several promising lines of research from rodent models aimed at reducing the neurotoxic effects of ethanol on the developing CNS or in treating the resulting behavioral impairments but these have not yet moved to clinical testing. The current review discusses some of the most promising targets for intervention and provides a review of the past and ongoing efforts to develop and screen pharmacological treatments for reducing the effects of prenatal ethanol exposure.

Genetic absence of nNOS worsens fetal alcohol effects in mice. I: behavioral deficits.

Alcohol abuse during pregnancy often induces neuropsychological problems in the offspring, including learning disorders, attention deficits, and behavior problems, all of which are prominent components of fetal alcohol spectrum disorders (FASD). However, not all children who were exposed to alcohol in utero are equally affected by it. While some children have major deficits, others are spared. This unequal vulnerability is likely due largely to differences in fetal genetics. Some fetuses appear to have certain genotypes that make them much more prone to FASD. However, to date, no gene has been identified that worsens alcohol-induced brain dysfunction. Nitric oxide (NO) is a gaseous molecule that can protect developing neurons against alcohol-induced death. In the brain, NO is produced by neuronal nitric oxide synthase (nNOS). In this study, we examined whether homozygous mutation of the nNOS gene in mice worsens the behavioral deficits of developmental alcohol exposure. Wild-type and nNOS(-/-) mice received alcohol (0.0, 2.2, or 4.4mg/g) daily over postnatal days (PDs) 4 to 9. Beginning on PD 85, the mice underwent a series of behavioral tests, including open field activity, the Morris water maze, and paired pulse inhibition. For the wild-type mice, alcohol impaired performance only in the water maze. In contrast, for the nNOS(-/-) mice, alcohol impaired performance on all 3 tasks. Furthermore, the nNOS(-/-) mice were substantially more impaired than wild-type mice in their performance on all 3 of the behavioral tests and at both the low (2.2) and high (4.4) doses of alcohol. Targeted disruption of the nNOS gene worsens the behavioral impact of developmental alcohol exposure and allows alcohol-induced learning problems to emerge that are not seen in wild type. This is the first demonstration that a specific genotype can interact with alcohol to worsen functional brain deficits in an animal model of FASD.

Genetic absence of nNOS worsens fetal alcohol effects in mice. II: microencephaly and neuronal losses.

Prenatal alcohol exposure can kill developing neurons, leading to microencephaly and mental retardation. However, not all fetuses are equally vulnerable to alcohol's neurotoxic effects. While some fetuses are severely affected and are ultimately diagnosed with fetal alcohol syndrome (FAS), others have no evidence of neuropathology and are behaviorally normal. These widely different outcomes among alcohol-exposed fetuses are likely due, in part, to genetic differences. Some fetuses possess genotypes that make them much more vulnerable than others to alcohol's teratogenic effects. However, to date, only 1 gene has been identified whose mutation can worsen alcohol-induced behavioral deficits in an animal model of FAS. That gene is neuronal nitric oxide synthase (nNOS). The purpose of this study was to determine whether mutation of nNOS can likewise worsen alcohol-induced microencephaly and lead to permanent neuronal deficits. Wild-type and nNOS(-/-) mice received alcohol (0.0, 2.2, or 4.4mg/g) daily over postnatal days (PDs) 4 to 9. Beginning on PD 85, the mice underwent a series of behavioral tests; the results of which are reported in the companion paper. The brains were then weighed, and stereological cell counts were performed on the cerebral cortex and hippocampal formation, which are the brain regions that mediate the aforementioned behavioral tasks. Alcohol caused dose-dependent microencephaly, but only in the nNOS(-/-) mice and not in wild-type mice. Alcohol-induced neuronal losses were more severe in the nNOS(-/-) mice than in the wild-type mice in all of the brain regions examined, including the cerebral cortex, hippocampal CA3 subregion, hippocampal CA1 subregion, and dentate gyrus. Targeted mutation of the nNOS gene increases the vulnerability of the developing brain to alcohol-induced growth restriction and neuronal losses. This increased neuropathology is associated with worsened behavioral dysfunction. The results demonstrate the critical importance of genotype in determining the outcome of developmental alcohol exposure.

Developmental ethanol exposure leads to dysregulation of lipid metabolism and oxidative stress in Drosophila.

Ethanol exposure during development causes an array of developmental abnormalities, both physiological and behavioral. In mammals, these abnormalities are collectively known as fetal alcohol effects (FAE) or fetal alcohol spectrum disorder (FASD). We have established a Drosophila melanogaster model of FASD and have previously shown that developmental ethanol exposure in flies leads to reduced expression of insulin-like peptides (dILPs) and their receptor. In this work, we link that observation to dysregulation of fatty acid metabolism and lipid accumulation. Further, we show that developmental ethanol exposure in Drosophila causes oxidative stress, that this stress is a primary cause of the developmental lethality and delay associated with ethanol exposure, and, finally, that one of the mechanisms by which ethanol increases oxidative stress is through abnormal fatty acid metabolism. These data suggest a previously uncharacterized mechanism by which ethanol causes the symptoms associated with FASD.

Importance of genetics in fetal alcohol effects: Null mutation of the nNOS gene worsens alcohol-induced cerebellar neuronal losses and behavioral deficits

The cerebellum is a major target of alcohol-induced damage in the developing brain. However, the cerebella of some children are much more seriously affected than others by prenatal alcohol exposure. As a consequence of in utero alcohol exposure, some children have substantial reductions in cerebellar volume and corresponding neurodevelopmental problems, including microencephaly, ataxia, and balance deficits, while other children who were exposed to similar alcohol quantities are spared. One factor that likely plays a key role in determining the impact of alcohol on the fetal cerebellum is genetics. However, no specific gene variant has yet been identified that worsens cerebellar function as a consequence of developmental alcohol exposure. Previous studies have revealed that mice carrying a homozygous mutation of the gene for neuronal nitric oxide synthase (nNOS−/− mice) have more severe acute alcohol-induced neuronal losses from the cerebellum than wild type mice. Therefore, the goals of this study were to determine whether alcohol induces more severe cerebellum-based behavioral deficits in nNOS−/− mice than in wild type mice and to determine whether these worsened behavior deficits are associated with worsened cerebellar neuronal losses. nNOS−/− mice and their wild type controls received alcohol (0.0, 2.2, or 4.4mg/g) daily over postnatal days 4–9. In adulthood, the mice underwent behavioral testing, followed by neuronal quantification. Alcohol caused dose-related deficits in rotarod and balance beam performance in both nNOS−/− and wild type mice. However, the alcohol-induced behavioral deficits were substantially worse in the nNOS−/− mice than in wild type. Likewise, alcohol exposure led to losses of Purkinje cells and cerebellar granule cells in mice of both genotypes, but the cell losses were more severe in the nNOS−/− mice than in wild type. Behavioral performances were correlated with neuronal number in the nNOS−/− mice, but not in wild type. Thus, homozygous mutation of the nNOS gene increases vulnerability to alcohol-induced cerebellar dysfunction and neuronal loss. nNOS is the first gene identified whose mutation worsens alcohol-induced cerebellar behavioral deficits.