Heavy drinking from adolescence to young adulthood is associated with an altered cerebellum

Atrophy and Higher Levels of Inflammatory-Related Markers in the Posterior Cerebellar Lobe Cortex in Chronic Alcohol Use Disorder: A Cross-Sectional Study

AIMS

Alcohol use disorder (AUD) involves excessive and chronic ethanol consumption, leading to various health issues, including cerebellar atrophy. The cerebellum is particularly susceptible to ethanol-induced damage through neuroinflammation, oxidative stress and excitotoxicity. This damage has been documented predominantly in the anterior lobe, primarily due to its role in motor function, which is often impaired in patients with AUD. However, less is known about the impact of AUD on the posterior cerebellar lobes. In contrast, alterations in the posterior lobe have been associated with cerebellar cognitive affective syndrome (CCAS). Moreover, the cerebellum is an asymmetric structure with spatial functions being left-lateralised. We hypothesised that the posterior cerebellar lobe in AUD cases would show increased inflammation compared with healthy controls.

METHODS

This cross-sectional study examined the structural integrity and neuroinflammatory state of the left posterior cerebellar lobe cortex in post-mortem samples from nine males with chronic AUD and 9 control cases.

RESULTS

Chronic AUD cases showed significant cerebellar damage. Immunohistochemistry revealed higher levels of reactive astrogliosis (GFAP), increased Treg cell markers (CD45 and FOXP3), increased mitochondria marker (MitoTrackerTM), elevated COX2 (indicating inflammation and Treg cell activity), increased cFos protein (cell activity marker), and higher caspase 3 (Casp3) levels, suggesting excessive cell death. These findings indicate that chronic AUD leads to atrophy in the left posterior cerebellar lobe cortex due to neuroinflammation driven by reactive astrogliosis, Treg cell infiltration, and COX2 activity.

CONCLUSIONS

The study highlights the inflammatory consequences of chronic AUD, potentially linked to cerebellar atrophy and subsequent motor and cognitive impairments. Targeting neuroinflammation could help mitigate the neurodegenerative effects of chronic AUD.

Excessive Alcohol Use as a Risk Factor for Alzheimer's Disease: Epidemiological and Preclinical Evidence

Alcohol use has recently emerged as a modifiable risk factor for Alzheimer's disease (AD). However, the neurobiological mechanisms by which alcohol interacts with AD pathogenesis remain poorly understood. In this chapter, we review the epidemiological and preclinical support for the interaction between alcohol use and AD. We hypothesize that alcohol use increases the rate of accumulation of specific AD-relevant pathologies during the prodromal phase and exacerbates dementia onset and progression. We find that alcohol consumption rates are increasing in adolescence, middle age, and aging populations. In tandem, rates of AD are also on the rise, potentially as a result of this increased alcohol use throughout the lifespan. We then review the biological processes in common between alcohol use disorder and AD as a means to uncover potential mechanisms by which they interact; these include oxidative stress, neuroimmune function, metabolism, pathogenic tauopathy development and spread, and neuronal excitatory/inhibitory balance (EIB). Finally, we provide some forward-thinking suggestions we believe this field should consider. In particular, the inclusion of alcohol use assessments in longitudinal studies of AD and more preclinical studies on alcohol's impacts using better animal models of late-onset Alzheimer's disease (LOAD).

Machine Learning of Functional Connectivity to Biotype Alcohol and Nicotine Use Disorders

BACKGROUND

Magnetic resonance imaging provides noninvasive tools to investigate alcohol use disorder (AUD) and nicotine use disorder (NUD) and neural phenotypes for genetic studies. A data-driven transdiagnostic approach could provide a new perspective on the neurobiology of AUD and NUD.

METHODS

Using samples of individuals with AUD (n = 140), individuals with NUD (n = 249), and healthy control participants (n = 461) from the UK Biobank, we integrated clinical, neuroimaging, and genetic markers to identify biotypes of AUD and NUD. We partitioned participants with AUD and NUD based on resting-state functional connectivity (FC) features associated with clinical metrics. A multitask artificial neural network was trained to evaluate the cluster-defined biotypes and jointly infer AUD and NUD diagnoses.

RESULTS

Three biotypes-primary NUD, mixed NUD/AUD with depression and anxiety, and mixed AUD/NUD-were identified. Multitask classifiers incorporating biotype knowledge achieved higher area under the curve (AUD: 0.76, NUD: 0.74) than single-task classifiers without biotype differentiation (AUD: 0.61, NUD: 0.64). Cerebellar FC features were important in distinguishing the 3 biotypes. The biotype of mixed NUD/AUD with depression and anxiety demonstrated the largest number of FC features (n = 5), all related to the visual cortex, that significantly differed from healthy control participants and were validated in a replication sample (p < .05). A polymorphism in TNRC6A was associated with the mixed AUD/NUD biotype in both the discovery (p = 7.3 × 10-5) and replication (p = 4.2 × 10-2) sets.

CONCLUSIONS

Biotyping and multitask learning using FC features can characterize the clinical and genetic profiles of AUD and NUD and help identify cerebellar and visual circuit markers to differentiate the AUD/NUD group from the healthy control group. These markers support a new growing body of literature.

Adolescent intermittent ethanol exposure alters adult exploratory and affective behaviors, and cerebellar Grin2b expression in C57BL/6J mice

Binge drinking is one of the most common patterns (more than 90%) of alcohol consumption by young people. During adolescence, the brain undergoes maturational changes that influence behavioral control and affective behaviors, such as cerebellar brain volume and function in adulthood. We investigated long-term impacts of adolescent binge ethanol exposure on affective and exploratory behaviors and cerebellar gene expression in adult male and female mice. Further, the cerebellum is increasingly recognized as a brain region integrating a multitude of behaviors that span from the traditional primary sensory-motor to affective functions, such as anxiety and stress reactivity. Therefore, we investigated the persistent effects of adolescent intermittent ethanol (AIE) on exploratory and affective behaviors and began to elucidate the role of the cerebellum in these behaviors through excitatory signaling gene expression. We exposed C57BL/6J mice to AIE or air (control) vapor inhalation from postnatal day 28-42. After prolonged abstinence (>34 days), in young adulthood (PND 77+) we assessed behavior in the open field, light/dark, tail suspension, and forced swim stress tests to determine changes in affective behaviors including anxiety-like, depressive-like, and stress reactivity behavior. Excitatory signaling gene mRNA levels of fragile X messenger ribonucleoprotein (FMR1), glutamate receptors (Grin2a, Grin2b and Grm5) and excitatory synaptic markers (PSD-95 and Eaat1) were measured in the cerebellum of adult control and AIE-exposed mice. AIE-exposed mice showed decreased exploratory behaviors in the open field test (OFT) where both sexes show reduced ambulation, however only females exhibited a reduction in rearing. Additionally, in the OFT, AIE-exposed females also exhibited increased anxiety-like behavior (entries to center zone). In the forced swim stress test, AIE-exposed male mice, but not females, spent less time immobile compared to their same-sex controls, indicative of sex-specific changes in stress reactivity. Male and female AIE-exposed mice showed increased Grin2b (Glutamate Ionotropic Receptor NMDA Type Subunit 2B) mRNA levels in the cerebellum compared to their same-sex controls. Together, these data show that adolescent binge-like ethanol exposure altered both exploratory and affective behaviors in a sex-specific manner and modified cerebellar Grin2b expression in adult mice. This indicates the cerebellum may serve as an important brain region that is susceptible to long-term molecular changes after AIE.

Adolescent Intermittent Ethanol Exposure Alters Adult Exploratory and Affective Behaviors, and Cerebellar Grin2B Expression in C57BL/6J Mice

Binge drinking is one of the most common patterns (more than 90%) of alcohol consumption by young people. During adolescence, the brain undergoes maturational changes that influence behavioral control and affective behaviors, such as cerebellar brain volume and function in adulthood. We investigated long-term impacts of adolescent binge ethanol exposure on affective and exploratory behaviors and cerebellar gene expression in adult male and female mice. Further, the cerebellum is increasingly recognized as a brain region integrating a multitude of behaviors that span from the traditional primary sensory-motor to affective functions, such as anxiety and stress reactivity. Therefore, we investigated the persistent effects of adolescent intermittent ethanol (AIE) on exploratory and affective behaviors and began to elucidate the role of the cerebellum in these behaviors through excitatory signaling gene expression. We exposed C57BL/6J mice to AIE or air (control) vapor inhalation from postnatal day 28-42. After prolonged abstinence (>34 days), in young adulthood (PND 77+) we assessed behavior in the open field, light/dark, tail suspension, and forced swim stress tests to determine changes in affective behaviors including anxiety-like, depressive-like, and stress reactivity behavior. Excitatory signaling gene mRNA levels of fragile X messenger ribonucleoprotein ( FMR1) , glutamate receptors ( Grin2a , Grin2B and Grm5 ) and excitatory synaptic markers (PSD-95 and Eaat1) were measured in the cerebellum of adult control and AIE-exposed mice. AIE-exposed mice showed decreased exploratory behaviors in the open field test (OFT) where both sexes show reduced ambulation, however only females exhibited a reduction in rearing. Additionally, in the OFT, AIE-exposed females also exhibited increased anxiety-like behavior (entries to center zone). In the forced swim stress test, AIE-exposed male mice, but not females, spent less time immobile compared to their same-sex controls, indicative of sex-specific changes in stress reactivity. Male and female AIE-exposed mice showed increased Grin2B (Glutamate Ionotropic Receptor NMDA Type Subunit 2B) mRNA levels in the cerebellum compared to their same-sex controls. Together, these data show that adolescent binge-like ethanol exposure altered both exploratory and affective behaviors in a sex-specific manner and modified cerebellar Grin2B expression in adult mice. This indicates the cerebellum may serve as an important brain region that is susceptible to long-term molecular changes after AIE.

Highlights

Adolescent intermittent ethanol (AIE) exposure decreased exploratory behavior in adult male and female mice.In females, but not males, AIE increased anxiety-like behavior.In males, but not females, AIE reduced stress reactivity in adulthood.These findings indicate sex differences in the enduring effects of AIE on exploratory and affective behaviors. Cerebellar Grin2B mRNA levels were increased in adulthood in both male and female AIE-exposed mice. These findings add to the small, but growing literature on behavioral AIE effects in mice, and establish cerebellar excitatory synaptic gene expression as an enduring effect of adolescent ethanol exposure.

Patterns of alcohol and alcohol-flavoured non-alcoholic beverage advertisements over Japanese free-to-air television networks

Background

Alcohol use is a serious public health challenge worldwide. Japan has no government regulations or legal penalties against advertising alcoholic beverages on television (TV). Instead, advertisements depend on the Japanese alcohol industry’s self-regulation on airtime (no advertisements from 5 am to 6 pm) and the content of alcoholic beverages, which must not tempt minors. However, many adolescents (10 to 19 years old) watch TV from 6 pm to 11 pm. The aim of this study was to describe the pattern in the advertising of alcoholic beverages and alcohol-flavoured non-alcoholic beverages (AFNAB) in Japan during the popular TV viewing time for adolescents.

Methods

A secondary analysis of advertising airtime data from five free-to-air Japanese TV networks in the Greater Tokyo area that aired between 12 August and 3 November 2019, was performed.

Results

During the study period, 5215 advertisements for alcoholic beverages and AFNABs aired (1451.75 min). In total, 2303 advertisements (44.2%) were beer, low-malt beer, or beer-taste beverages, 277 (5.3%) were whisky, 2334 (44.8%) were local alcoholic beverages (shochu and seishu), and 301 (5.8%) were AFNAB. On average, more advertisements aired on weekends (67.6 advertisements) than on weekdays (59.3 advertisements) per day. Approximately 30% of advertisements for AFNABs were aired during the time restricted for alcohol advertising, although AFNABs are considered alcohol according to industry guidelines. During the popular television viewing time for young adolescents, about two to three times more advertisements were aired per hour than during the rest of the day, on both weekdays and weekends (p < 0.001).

Conclusion

The number of alcohol advertisements aired at times when adolescents often watch TV is 2 to 3.2 times higher than that at other times of the day. Furthermore, despite the industry’s self-imposed regulations, some alcoholic beverages are still advertised. Therefore, other methods to protect children and adolescents from exposure to advertisements for alcoholic beverages should be investigated and implemented.