Cross-Sectional Analysis of Spatial Working Memory Development in Children with Histories of Heavy Prenatal Alcohol Exposure

Effects of genetics and sex on adolescent behaviors following neonatal ethanol exposure in BXD recombinant inbred strains

Introduction

Fetal alcohol spectrum disorders (FASD) are the leading preventable neurodevelopmental disorders and two hallmark symptoms of FASD are abnormal behavior, and cognitive and learning deficits. The severity of alcohol's teratogenic effects on the developing brain is influenced by genetics and sex. We previously identified recombinant inbred BXD mouse strains that show differential vulnerability to ethanol-induced cell death in the developing hippocampus, a brain region important in learning and memory. The present study aimed to test the hypothesis that strains with increased vulnerability to ethanol-induced cell death in the hippocampus have concomitant deficits in multiple hippocampal-related behaviors during adolescence.

Methods

The current study evaluated the effects of developmental ethanol exposure on adolescent behavior in two BXD strains that show high cell death (BXD48a, BXD100), two that show low cell death (BXD60, BXD71), and the two parental strains (C57BL/6 J (B6), DBA/2 J (D2)). On postnatal day 7, male and female neonatal pups were treated with ethanol (5.0 g/kg) or saline given in two equal doses 2 h apart. Adolescent behavior was assessed across multiple behavioral paradigms including the elevated plus maze, open field, Y-maze, and T-maze.

Results

Our results demonstrate that the effects of developmental ethanol exposure on adolescent behavioral responses are highly dependent on strain. The low cell death strains, BXD60 and BXD71, showed minimal effect of ethanol exposure on all behavioral measures but did present sex differences. The parental -B6 and D2-strains and high cell death strains, BXD48a and BXD100, showed ethanol-induced effects on activity-related or anxiety-like behaviors. Interestingly, the high cell death strains were the only strains that showed a significant effect of postnatal ethanol exposure on hippocampal-dependent spatial learning and memory behaviors.

Discussion

Overall, we identified effects of ethanol exposure, strain, and/or sex on multiple behavioral measures. Interestingly, the strains that showed the most effects of postnatal ethanol exposure on adolescent behavior were the BXD strains that show high ethanol-induced cell death in the neonatal hippocampus, consistent with our hypothesis. Additionally, we found evidence for interactions among strain and sex, demonstrating that these factors have a complex effect on alcohol responses and that both are important considerations.

Prenatal alcohol and tetrahydrocannabinol exposure: Effects on spatial and working memory

Introduction

Alcohol and cannabis are widely used recreational drugs that can negatively impact fetal development, leading to cognitive impairments. However, these drugs may be used simultaneously and the effects of combined exposure during the prenatal period are not well understood. Thus, this study used an animal model to investigate the effects of prenatal exposure to ethanol (EtOH), Δ-9-tetrahydrocannabinol (THC), or the combination on spatial and working memory.

Methods

Pregnant Sprague-Dawley rats were exposed to vaporized ethanol (EtOH; 68 ml/h), THC (100 mg/ml), the combination, or vehicle control during gestational days 5-20. Adolescent male and female offspring were evaluated using the Morris water maze task to assess spatial and working memory.

Results

Prenatal THC exposure impaired spatial learning and memory in female offspring, whereas prenatal EtOH exposure impaired working memory. The combination of THC and EtOH did not exacerbate the effects of either EtOH or THC, although subjects exposed to the combination were less thigmotaxic, which might represent an increase in risk-taking behavior.

Discussion

Our results highlight the differential effects of prenatal exposure to THC and EtOH on cognitive and emotional development, with substance- and sex-specific patterns. These findings highlight the potential harm of THC and EtOH on fetal development and support public health policies aimed at reducing cannabis and alcohol use during pregnancy.

Neurodevelopmental Trajectories Following Prenatal Alcohol Exposure

Prenatal alcohol exposure (PAE) interferes with neurodevelopment. The brain is particularly susceptible to the adverse consequences of prenatal alcohol exposure, and numerous studies have documented changes to brain anatomy and function, as well as consequences for cognition, behavior, and mental health. Studies in typically developing individuals have shown that the brain undergoes dynamic developmental processes over an individual’s lifespan. Furthermore, magnetic resonance imaging (MRI) studies in other neurodevelopmental and psychiatric disorders have shown that their developmental trajectories differ from the typical pattern. Therefore, to understand long-term clinical outcomes of fetal alcohol spectrum disorders (FASD), it is necessary to investigate changes in neurodevelopmental trajectories in this population. Here we review studies that have used MRI to evaluate changes in brain structure and function over time via cross-sectional or longitudinal methods in individuals with PAE. Research demonstrates that individuals with PAE have atypical cortical and white matter microstructural developmental trajectories through childhood and adolescence. More research is needed to understand how factors such as sex and postnatal experiences may further mediate these trajectories. Furthermore, nothing is known about the trajectories beyond young adulthood.

The Importance of Creating Habilitation Programs for Children with Fetal Alcohol Syndrome and Fetal Alcohol Spectrum Disorders

Aim of the study: to analyze the data of studies aimed at studying and substantiating the urgent need to create in Russia comprehensive habilitation programs for people with fetal alcohol syndrome, fetal alcohol spectrum disorders and other mental disorders.

Methods. The results of Russian and foreign studies have been analyzed concerning the following problems: observation and diagnosis of people with fetal alcohol syndrome and fetal alcohol spectrum disorders; studying the experience of foreign countries in addressing issues of prevention and overcoming of fetal alcohol syndrome and fetal alcohol spectrum disorders; studying the experience of Russian specialists (obstetricians-gynecologists, neurologists, psychiatrists, psychologists, correctional teachers, etc.) working with the diagnosis of “Alcohol syndrome in the fetus”; assessing the socio-economic impact of organizing programs for the prevention of fetal alcohol syndrome and fetal alcohol spectrum disorders by comparison with similar indicators in other countries.

Results. The presented analysis of the data indicates that there is an urgent need for timely diagnosis of the disease, the search/creation of new drugs, for the treatment of the consequences of alcohol syndrome and the organization of training of specialists in this area. The article shows the importance of providing lifelong medical and social assistance to people with fetal alcohol spectrum disorders, as well as to their families. The effectiveness of the creation of a system of measures for the prevention of fetal alcohol syndrome and fetal alcohol spectrum disorders throughout the country has been confirmed.

Conclusion. The development at the state level and implementation of prevention programs will significantly reduce the birth rate of children diagnosed with “Alcohol syndrome in the fetus” and, thus, reduce the costs of the state and society on overcoming the consequences of FAS/FASD. At the same time, timely and well-organized habilitation of people with FAS/FASD will significantly improve the social situation in society as a whole, as well as reduce the psychological burden on every family faced with this problem.