Fetal brain function in response to maternal alcohol consumption: early evidence of damage

Prenatal ethanol exposure impairs sensory processing and habituation to visual stimuli, effects normalized by enrichment of postnatal environmental

BACKGROUND

Individuals with fetal alcohol spectrum disorders (FASD) often show processing deficits in all sensory modalities. Using an operant light reinforcement model, we tested whether prenatal ethanol exposure (PE) alters operant responding to elicit a contingent sensory stimulus-light onset (turning on the light) and habituation to this behavior in rats. We also explored whether postnatal environmental enrichment could ameliorate PE-induced deficits.

METHODS

Pregnant Sprague Dawley rats were gavaged twice/day with 0 or 3 g/kg/treatment ethanol (15% w/v) during gestational days 8-20, mimicking second-trimester heavy PE in humans. The offspring were reared in a standard housing condition or an enriched condition. Adult male and female offspring underwent an operant light reinforcement experiment with either a short-access or a long-access procedure. A dishabituation test was also conducted to characterize the habituation process.

RESULTS

In the short-access procedure, PE led to increased operant responding to the contingent light onset in both sexes reared in the standard housing condition. Such an effect was not observed in rats reared in enriched conditions due to an overall decrease in responding. Moreover, rats reared in enriched conditions showed greater short-term habituation. In the long access procedure, PE rats showed increased responding and impaired long-term habituation. The long-access procedure facilitated both short-term and long-term habituation in control and PE rats.

CONCLUSION

Prenatal ethanol exposure increases responding to contingent light onset and impairs the long-term habituation process. The PE-induced deficits were ameliorated by rearing in the enriched environment and increasing the duration and frequency of exposure to light onset. The PE-induced effects are like increased sensation-seeking, a subtype of sensory-processing deficit that is often observed in individuals with FASD. Our findings could inform a suitable animal model for investigating the underlying mechanisms and possible intervention strategies for sensory deficits in FASD.

Prenatal origins of neuropsychiatric diseases

AIM

The main objective is to review the available evidence in the literature for developmental origins of neuropsychiatric diseases and their underlying mechanisms. We also probe emerging cutting-edge prenatal MR imaging tools and their future role in advancing our understanding the prenatal footprints of neuropsychiatric disorders.

OBSERVATIONS

Both human and animal studies support early intrauterine origins of neuropsychiatric disease, particularly autism spectrum disorders (ASD), attention and hyperactivity disorders, schizophrenia, depression, anxiety and mood disorders. Specific mechanisms of intrauterine injury include infection, inflammation, hypoxia, hypoperfusion, ischaemia polysubstance use/abuse, maternal mental health and placental dysfunction.

CONCLUSIONS AND RELEVANCE

There is ample evidence to suggest developmental vulnerability of the foetal brain to intrauterine exposures that increases and individual's risk for neuropsychiatric disease, especially the risk of ASD, depression and anxiety. Elucidating the exact timing and mechanisms of injury can be difficult and require novel, non-invasive approaches to the study emerging structural and functional brain development of the foetus. Clinical care should both emphasise maternal health during pregnancy, as well as close, continued monitoring for at risk offspring throughout young adulthood for the early identification and treatment of neuropsychiatric diseases.

Binge drinking during pregnancy and psychosis-like experiences in the child at age 11

Increased frequency of psychosis-like experiences (PLEs) has been previously reported in children born to mothers with high general levels of alcohol intake during pregnancy. The aim of this study was to examine whether the risk of PLEs was likewise elevated in children prenatally exposed to binge drinking. Participants were 44,326 children and their mothers enrolled in the Danish National Birth Cohort from 1996-2002. Information on maternal binge drinking was collected twice in pregnancy by telephone interview and PLEs in the children were ascertained in a Web-based questionnaire at age 11. Analyses were carried out using weighted multinomial logistic regression models. Maternal binge drinking was relatively common among the participating women (27%). The adjusted relative risk ratio (RRR) for reporting one definite PLE symptom was 1.04 (95% confidence interval (CI) 0.95-1.13) and 1.06 (95% CI 0.95-1.20) for two or more symptoms in children exposed compared to unexposed to binge drinking during pregnancy. Furthermore, no association was found when addressing frequency and timing of binge drinking, nor for various levels of average alcohol consumption. When sub-dividing PLEs into specific types of experiences however, a slightly, although non-significant, increased risk was observed for one specific delusional idea, receiving messages from radio/TV, following prenatal exposure to binge drinking. Our results provide no evidence of an association between maternal binge drinking, nor average alcohol consumption in pregnancy, and overall occurrence of PLEs in the offspring. However, our results indicated that binge drinking might be related to a specific PLE.

Changes in event-related brain responses and habituation during child development - A systematic literature review

OBJECTIVE

This systematic review highlights the influence of developmental changes of the central nervous system on habituation assessment during child development. Therefore, studies on age dependant changes in event-related brain responses as well as studies on behavioural and neurophysiological habituation during child development are compiled and discussed.

METHODS

Two PubMed searches with terms "(development evoked brain response (fetus OR neonate OR children) (electroencephalography OR magnetoencephalography))" and with terms "(psychology habituation (fetal OR neonate OR children) (human brain))" were performed to identify studies on developmental changes in event-related brain responses as well as habituation studies during child development.

RESULTS

Both search results showed a wide diversity of subjects' ages, stimulation protocols and examined behaviour or components of event-related brain responses as well as a demand for more longitudinal study designs.

CONCLUSIONS

A conclusive statement about clear developmental trends in event-related brain responses or in neurophysiological habituation studies is difficult to draw. Future studies should implement longitudinal designs, combination of behavioural and neurophysiological habituation measurement and more complex habituation paradigms to assess several habituation criteria.

SIGNIFICANCE

This review emphasizes that event-related brain responses underlie certain changes during child development which should be more considered in the context of neurophysiological habituation studies.

Assessing the prevalence of alcohol consumption in early pregnancy using blood biomarker analysis: a consistent pattern across north-east England?

Background

We previously investigated the prevalence of alcohol consumption in early pregnancy in Northumbria Healthcare NHS Foundation Trust, a locality of north-east England. The prevalence was 1.4% based on blood sample biomarker analysis using carbohydrate deficient transferrin (CDT) and 3.5% for gamma-glutamyltransferase (GGT).

Aims

To supplement this research by investigating the prevalence of alcohol use using identical methods in a different locality of the same region.

Methods

Six-hundred random blood samples taken at the antenatal booking appointment were anonymously analysed for the presence of CDT, a validated marker of chronic alcohol exposure (normalizing 2–3 weeks from abstinence) and GGT, a liver enzyme elevated for up to 8 weeks after alcohol exposure.

Results

The North Tees and Hartlepool NHS Foundation Trust data revealed a CDT prevalence rate of 1.7% (95% CI: 0.7–2.9) and GGT prevalence rate of 4.2% (95% CI: 2.6–5.9). However, these measures are not sensitive to low levels of alcohol; and no overlapping cases were identified or a significant correlation demonstrated between CDT or GGT.

Discussion

These data support our earlier work. Prevalence rates according to CDT and GGT analysis were similar in both areas, suggesting similar patterns of sustained alcohol use in pregnancy across the region.

Assessing prevalence of alcohol consumption in early pregnancy: Self-report compared to blood biomarker analysis

Providing appropriate antenatal and postnatal care for women who drink alcohol in pregnancy is only possible if those at risk can be identified. We aimed to compare the prevalence of alcohol consumption in the first trimester of pregnancy using self-report and blood biomarker analysis. Six-hundred routine blood samples from 2014, taken at the antenatal booking appointment, in the first trimester of pregnancy, were anonymously analysed for the presence of Carbohydrate Deficient Transferrin (CDT), a validated marker of chronic alcohol exposure (normalising 2-3 weeks from abstinence) and Gamma-glutamyltransferase (GGT), a liver enzyme elevated for up to 8 weeks after alcohol exposure. In a separate sample of women, from 2015, data taken during the antenatal visit, documenting women's self-reported alcohol consumption, were collected. The percentage of women who reported alcohol intake in the first trimester was 0.8%. This compared to 74.1% of women who reported consuming alcohol before pregnancy. CDT analysis revealed a prevalence rate of 1.4% and GGT a prevalence rate of 3.5% in the first trimester of pregnancy. Although those with elevated CDT generally had high levels of GGT, only one person was positive for CDT and GGT. Results from CDT analysis and self-report may underestimate prevalence for different reasons. GGT appeared to lack specificity, but it may have value in supporting findings from CDT analysis. Further studies using additional blood biomarkers, or a combination of blood biomarkers and self-report, may be beneficial in accurately detecting alcohol drinking history in pregnancy.

Neuromagnetic signatures of syllable processing in fetuses and infants provide no evidence for habituation

BACKGROUND

Habituation, as a basic form of learning, is characterized by decreasing amplitudes of neuronal reaction following repeated stimuli. Recent studies indicate that habituation to pure tones of different frequencies occurs in fetuses and infants.

AIMS

Neural processing of different syllables in fetuses and infants was investigated.

STUDY DESIGN

An auditory habituation paradigm including two different sequences of syllables was presented to each subject. Each sequence consisted of eight syllables (sequence /ba/: 5× /ba/, 1× /bi/ (dishabituator), 2× /ba/; sequence /bi/: 5× /bi/, 1× /ba/ (dishabituator), 2× /bi/). Each subject was stimulated with 140 sequences. Neuromagnetic signatures of auditory-evoked responses (AER) were recorded by fetal magnetoencephalography (fMEG).

SUBJECTS

Magnetic brain signals of N=30 fetuses (age: 28-39weeks of gestation) and N=28 infants (age: 0-3months) were recorded. Forty-two of the 60 fetal recordings and 29 of the 58 infant recordings were included in the final analysis.

OUTCOME MEASURES

AERs were recorded and amplitudes were normalized to the amplitude of the first stimulus.

RESULTS

In both fetuses and infants, the amplitudes of AERs were found not to decrease with repeated stimulation. In infants, however, amplitude of syllable 6 (dishabituator) was significantly increased compared to syllable 5 (p=0.026).

CONCLUSIONS

Fetuses and infants showed AERs to syllables. Unlike fetuses, infants showed a discriminative neural response to syllables. Habituation was not observed in either fetuses or infants. These findings could be important for the investigation of early cognitive competencies and may help to gain a better understanding of language acquisition during child development.

Impact of fetal alcohol exposure on body systems: A systematic review

Review of published manuscripts on fetal alcohol exposure on several body systems.

METHOD

Articles in this review were found online using databases such as Medline, Medline Complete, PubMed, and Health Source: Nursing/Academic Edition. The following terms were searched: fetal alcohol spectrum disorders, fetal alcohol syndrome, prenatal alcohol exposure, and alcohol related birth defects.

RESULTS

Thirteen articles were gathered, five original investigations and eight reviews. This review identified several abnormalities in the body systems discussed and their associations to fetal alcohol syndrome.

CONCLUSIONS

Evidence shows that the brain was the most severely impacted organ of the body systems discussed. However, prenatal alcohol exposure causes several abnormalities within the heart, kidney, liver, gastrointestinal tract, and the endocrine systems. In addition, preventative measures need to be taken by mothers during pregnancy. Birth Defects Research (Part C), 2016. © 2016 Wiley Periodicals, Inc. Birth Defects Research (Part C) 108:174-180, 2016. © 2016 Wiley Periodicals, Inc.

Development of a Conceptual Model for Smoking Cessation: Physical Activity, Neurocognition, and Executive Functioning

PURPOSE

Considerable research has shown adverse neurobiological effects of chronic alcohol use, including long-term and potentially permanent changes in the structure and function of the brain; however, much less is known about the neurobiological consequences of chronic smoking, as it has largely been ignored until recently. In this article, we present a conceptual model proposing the effects of smoking on neurocognition and the role that physical activity may play in this relationship as well as its role in smoking cessation.

METHODS

Pertinent published peer-reviewed articles deposited in PubMed delineating the pathways in the proposed model were reviewed.

RESULTS

The proposed model, which is supported by emerging research, demonstrates a bidirectional relationship between smoking and executive functioning. In support of our conceptual model, physical activity may moderate this relationship and indirectly influence smoking behavior through physical activity-induced changes in executive functioning.

CONCLUSIONS

Our model may have implications for aiding smoking cessation efforts through the promotion of physical activity as a mechanism for preventing smoking-induced deficits in neurocognition and executive function.

Supplemental choline does not attenuate the effects of neonatal ethanol administration on habituation of the heart rate orienting response in rats

Several studies using rodent subjects have now shown that extra dietary choline may prevent or even reverse the deleterious effects of pre- and early post-natal ethanol administration. Choline supplementation has been shown to attenuate many, although not all, of ethanol's effects on brain development and behavior. Our laboratory has consistently reported impaired habituation of the heart rate orienting response to a novel olfactory stimulus in animals exposed to ethanol on postnatal days (PD) 4-9. Here we examine whether supplemental choline given both during and after ethanol administration could alleviate these ethanol-induced deficits. Subjects were given 5g/kg/day ethanol or sham intubations on PD 4-9. Half of the subjects in each group were given a single daily s.c. injection of choline chloride on PD 4-20, while the other half were injected daily with saline. Pups were tested for heart rate orienting and response habituation in a single test session on PD 23. Results replicated the ethanol-induced impairment in response habituation. However, choline supplementation had no effect on orienting or habituation in either neonatal treatment group. These findings indicate that habituation deficits induced by ethanol are not alleviated by extra dietary choline using these parameters. Choline holds great promise as a treatment for some fetal alcohol effects, but is not an effective treatment for all ethanol-related deficits.

Fetal alcohol spectrum disorders and neuroimmune changes

The behavioral consequences of fetal alcohol spectrum disorders (FASD) are serious and persist throughout life. The causative mechanisms underlying FASD are poorly understood. However, much has been learned about FASD from human structural and functional studies as well as from animal models, which have provided a greater understanding of the mechanisms underlying FASD. Using animal models of FASD, it has been recently discovered that ethanol induces neuroimmune activation in the developing brain. The resulting microglial activation, production of proinflammatory molecules, and alteration in expression of developmental genes are postulated to alter neuron survival and function and lead to long-term neuropathological and cognitive defects. It has also been discovered that microglial loss occurs, reducing microglia's ability to protect neurons and contribute to neuronal development. This is important, because emerging evidence demonstrates that microglial depletion during brain development leads to long-term neuropathological and cognitive defects. Interestingly, the behavioral consequences of microglial depletion and neuroimmune activation in the fetal brain are particularly relevant to FASD. This chapter reviews the neuropathological and behavioral abnormalities of FASD and delineates correlates in animal models. This serves as a foundation to discuss the role of the neuroimmune system in normal brain development, the consequences of microglial depletion and neuroinflammation, the evidence of ethanol induction of neuroinflammatory processes in animal models of FASD, and the development of anti-inflammatory therapies as a new strategy for prevention or treatment of FASD. Together, this knowledge provides a framework for discussion and further investigation of the role of neuroimmune processes in FASD.

Early fetal binge alcohol exposure predicts high behavioral symptom scores in 5.5-year-old children

BACKGROUND

Fetal binge alcohol exposure has been associated with neurobehavioral and cognitive symptoms. This study explored whether binge drinking mainly before recognition of pregnancy predicted high symptom scores on the Strengths and Difficulties Questionnaire (SDQ) in 5.5-year-old children.

METHODS

In a population-based, longitudinal study representative of pregnant women in Oslo, Norway, questionnaires were answered at 17 and 30 weeks of pregnancy, 6 months after term, and at child age 5.5 years (n = 1,116, constituting 66% of the original cohort). Logistic regression analyses identified factors predicting high SDQ scores, and multiple regression analyses identified direct effects on the SDQ Total.

RESULTS

Binge exposure (≥5 standard units per occasion [SUpo]) during pregnancy week 0 to 6, that is, 0 to 4 weeks after conception, predicted scores in the Abnormal and Borderline range on the SDQ in 5.5-year-olds, after adjusting for other confounding variables. Very early binge exposure less often than once a week predicted high symptom scores on the SDQ Total (p = 0.05) and Hyperactivity/Inattention (significant), while exposure at least once a week demonstrated a 3- to 5-fold significant increase in high symptom scores on Total, Emotional, and Conduct problems. Reporting ≥8 SUpo had stronger predictive power than reporting 5 to 7 SUpo. The results were not explained by participants reporting major lifetime depression. Other predictive factors, although weaker, were maternal symptoms of depression and anxiety during the child's infancy. High education (mother and father), high income (maternal partner), higher child birth weight, and child female sex reduced the likelihood of high SDQ symptom scores. Path analysis demonstrated early binge exposure to have a direct effect on the SDQ Total score.

CONCLUSIONS

Binge drinking up to 4 weeks after conception had a strong and direct predictive effect on SDQ symptom scores in 5.5-year-olds. These results strongly support the advice to avoid binge drinking when planning pregnancy.