Alcohol Use Disorder: Neurobiology and Therapeutics

BK channels and alcohol tolerance: Insights from studies on Drosophila, nematodes, rodents and cell lines: A systematic review

Addictive disorders markedly affect the emotional, physical and financial wellbeing of individuals, placing a substantial burden on the healthcare system. With their widespread presence in the brain, large-conductance calcium and voltage-activated potassium (BK) channels play a crucial role in various aspects of neuronal function. They contribute to behavioral tolerance and are closely linked to neuronal activity and modulation through intracellular calcium levels. As such, BK channels serve as key models for investigating the mechanisms of the effects of alcohol. Investigating their role in alcohol tolerance provides a broader understanding of their physiological and pharmacological importance. The present systematic review examined the literature on the role of BK channels in alcohol tolerance and comprehensively explored the topic. For this purpose, two databases, Web of Science and PubMed, were searched, and studies published from 2000 until June, 2024 were included. After applying specific inclusion and exclusion criteria, 35 studies underwent analysis to present a chronological overview of BK channels and their relevance in alcohol tolerance development. The studies were categorized into four main groups, according to research conducted on: i) Fruit flies; ii) nematodes; iii) rodents; and iv) cell lines. Understanding the mechanisms through which alcohol interacts with these channels may help to elucidate the cellular and molecular mechanisms underlying alcohol tolerance. There is a growing interest in developing drugs that can precisely modulate BK channel activity to treat alcohol dependence and tolerance. However, additional studies are required to fully explain the complex mechanisms through which BK channels influence alcohol-related behaviors and to interpret these findings into clinical applications.

Functional brain connectivity of the salience network in alcohol use and anxiety disorders

The interplay between alcohol use disorder (AUD) and anxiety disorders (ANX) is well-documented, yet the underlying neurobiological mechanisms remain elusive. This study aims to elucidate these mechanisms by examining the resting-state functional connectivity (RSFC) within the salience network and to the amygdala, both implicated in alcohol and anxiety disorders. We analyzed data from 264 inpatient participants culled from a wider group of 518 inpatients at The Menninger Clinic in Houston, TX, categorized into four groups (n = 66 each) based on DSM-IV diagnoses: AUD without ANX (AUD), ANX without AUD (ANX), concurrent AUD and ANX (BOTH), and neither (NEITHER). Our findings reveal significant RSFC differences, particularly between the right supramarginal gyrus (SMG) and 1) right rostral prefrontal cortex (RPFC) (corrected p = 0.029; RSFC significantly higher in NEITHER than in BOTH), and 2) left supramarginal gyrus (SMG) (corrected p = 0.016; RSFC significantly higher in AUD and NEITHER than in BOTH). Furthermore, correlations with a clinical measure for alcohol use (World Health Organization Alcohol, Smoking and Substance Involvement Screening Test; WHO ASSIST) indicated significant relationships: WHO ASSIST alcohol scores negatively correlated with right SMG to right RPFC RSFC (r = -0.14, p = 0.02) and positively correlated with the interhemispheric SMG RSFC (r = 0.17, p = 0.006). This research enhances our understanding of the complex neurobiological interconnections between alcohol use and anxiety disorders, suggesting a disrupted neural architecture that may underpin the behavioral manifestations observed in these highly comorbid conditions.

Association between 5-HTRs gene polymorphism and alcohol use disorder in Han males from Yunnan, China

Alcohol use disorder (AUD) has become a very serious medical and social problem. It is found that genetic polymorphisms of the 5-hydroxytryptamine receptors (5-HTRs) genes were associated with the risk of AUD. However, the results are controversial among different ethnic groups. At present, the correlation between 5-HTRs gene polymorphism and AUD in Han population from Yunnan Province remains unclear. In this study, 13 single nucleotide polymorphisms (SNPs) of HTR1B, HTR2A, HTR3A, HTR3B and HTR7 were detected by universal fluorescent probe technique. The CT genotype frequency of HTR3A rs1062613 was significantly higher in AUD case group than that in control group (P = 0.037, OR = 2.193, 95% CI: 1.048-4.366). The study indicated that the genetic polymorphisms of 5-HTRs were significantly associated with risk of AUD in Han male from Yunnan, China. In addition, this study further demonstrated the impact of alcohol on human health, especially liver damage, by analyzing the blood biochemical indicators of patients with AUD and combining them with their medical history.

Reduced gray matter volume in limbic and cortical areas is associated with anxiety and depression in alcohol use disorder patients

Alcohol use disorder (AUD) is a multifactorial disease closely related to neurodevelopment and environmental factors that influence behavior. This study explored the relationships between brain volume and behavior from an Exploratory Structural Equation Modeling (ESEM) based on the Research Domain Criteria. High-resolution magnetic resonance imaging scans were acquired from recent patients with AUD (n = 50) and healthy controls (HC=50). Group differences were assessed by means of voxel-based morphometry (VBM) and regions of interest (ROIs). Participants completed a battery of neurocognitive tasks and emotional tests. When controlling for age, education levels, and total intracranial volume, we found lower gray matter volume in cortical and limbic areas, as well as significant impairments in the AUD group on cognition and affective status. This study demonstrated the importance of multifactorial analysis and complex models in order to better understand substance use disorders. The brain losses may have been the result of neurodevelopmental impairments due to biological and environmental factors that predisposed to AUD or the result of drug abuse. The ESEM indicated that limbic areas indirectly affected the alcohol severity through emotional dysfunction. These results suggest a more relevant involvement of limbic regions for the severity of alcohol use, showing a more significant association between AUD and mood disorders.

History of Alcohol Use Disorder and Housing Instability as Predictors of Fatigue and Mental Health Problems During the COVID-19 Pandemic

Mental health and alcohol problems are significant public health concerns amid the COVID-19 pandemic. Housing instability and symptoms of fatigue are understudied aspects of the pandemic. This study examined history of Alcohol Use Disorder (AUD), history of COVID-19 infection, and housing instability as correlates of fatigue, anxiety, and depression symptoms. Data were drawn from 250 adults enrolled in an online survey within the NIAAA COVID-19 Pandemic Impact on Alcohol Study in between April 6 and June 2 of 2022. Participants completed self-report measures of housing stability, fatigue, and mental health symptoms. Multivariable analyses controlling for age, sex, race, ethnicity, and household income were conducted. Individuals with a history of AUD reported higher mental fatigue, anxiety symptoms, and depressive symptoms when compared to those with no history of AUD. Individuals with "other" housing arrangements (not renting or owning) reported higher mental fatigue, pandemic fatigue, anxiety symptoms, and depressive symptoms relative to homeowners. Individuals who worried about not having a place to live in the past 6 months reported higher physical fatigue, mental fatigue, anxiety symptoms, and depressive symptoms when compared to individuals without housing worry. History of COVID-19 infection was neither associated with mental health nor fatigue symptoms. Housing instability, as captured by housing worry and having "other" housing arrangements, was associated with greater fatigue and mental health problems, even after controlling for household income. Housing instability uniquely contributed to mental health symptoms, warranting further research and targeted prevention and intervention efforts.

The Implementation of the Biopsychosocial Model: Individuals With Alcohol Use Disorder and Post-Traumatic Stress Disorder

INTRODUCTION

This extensive literature review investigates the relationship between post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD), focusing on the neurobiological changes associated with their co-occurrence. Given that these disorders frequently coexist, we analyze mechanisms through which alcohol serves as a coping strategy for PTSD symptoms, particularly highlighting the drinking-to-cope self-medication model, which suggests that alcohol use exacerbates PTSD symptoms and complicates recovery.

METHODS

A systematic literature search was conducted across multiple databases, including PubMed and Google Scholar, to identify studies examining the intersection of the biopsychosocial model with PTSD, AUD, and associated neural alterations.

RESULTS

Findings demonstrate that chronic PTSD is associated with progressive dysfunction in the amygdala, hippocampus, prefrontal cortex, hypothalamic-pituitary-adrenal axis, and white matter pathways. Also, our findings underscore alterations within the reward system, prefrontal cortex, hippocampus, amygdala, basal ganglia, and hypothalamic-pituitary-adrenal axis that contribute to the pathophysiology of AUD. Our results support the notion that a biopsychosocial framework is essential for contemporary addiction treatment, particularly in the context of alcohol addiction and PTSD.

CONCLUSION

PTSD frequently leads individuals to use alcohol as a maladaptive coping strategy, ultimately resulting in neuroadaptive alterations across critical brain regions. These neurobiological changes contribute to the development and maintenance of AUD. The findings reiterate the necessity of employing a biopsychosocial model in treating individuals grappling with both PTSD and AUD. This model allows for a comprehensive understanding of the unique challenges faced by this population, integrating biological, psychological, and social factors that influence recovery.

Region-Specific Gene Expression Changes Associated with Oleoylethanolamide-Induced Attenuation of Alcohol Self-Administration

Oleoylethanolamide (OEA) is a lipid with anti-inflammatory activity that modulates multiple reward-related behaviors. Previous studies have shown that OEA treatment reduces alcohol self-administration (SA) while inhibiting alcohol-induced inflammatory signaling. Nevertheless, the specific mechanisms that OEA targets to achieve these effects have not been widely explored. Here, we tested the effects of OEA treatment during alcohol SA, extinction or previous to cue-induced reinstatement of alcohol seeking. In addition, we measured gene expression changes in the striatum and hippocampus of relevant receptors for alcohol consumption (Drd1, Drd2, Cnr1, Oprm) as well as immune-related proteins (Il-6, Il-1β, Tlr4) and the brain-derived neurotrophic factor (Bdnf). Our results confirmed that when administered contingently, systemic OEA administration reduced alcohol SA and attenuated cue-induced reinstatement. Interestingly, we also observed that OEA treatment reduced the number of sessions needed for the extinction of alcohol seeking. Biochemical analyses showed that OEA induced gene expression changes in dopamine and cannabinoid receptors in the striatum and hippocampus. In addition, OEA treatment modulated the long-term immune response and increased Bdnf expression. These results suggest that boosting OEA levels may be an effective strategy for reducing alcohol SA and preventing relapse.

The CB1 negative allosteric modulator PSNCBAM-1 reduces ethanol self-administration via a nonspecific hypophagic effect

Alcohol use disorder (AUD) affects >15 million people in the United States. Current pharmacotherapeutic treatments for AUD are only modestly effective, necessitating the identification of new targets for medications development. The cannabinoid receptor type 1 (CB1) has been a target of interest for the development of medications for substance use disorders and other compulsive disorders. However, CB1 antagonists/inverse agonists (e.g., rimonabant) have severe side effects that limit their clinical utility, including anxiety, depression, and suicide. Recent development of CB1 negative allosteric modulators (NAMs), including PSNCBAM-1, may provide an alternative mechanism of attenuating CB1 signaling with reduced side effects. PSNCBAM-1 has not yet been evaluated for effects in models of AUD. In this study, we investigated the effects of the CB1 NAM, PSNCBAM-1, in rodent models of AUD using adult male mice. PSNCBAM-1 dose-dependently attenuated oral ethanol self-administration (8 % w/v ethanol in water), significantly reducing ethanol rewards at a dose of 30 mg/kg, but not at 10 or 18 mg/kg. PSNCBAM-1 also dose-dependently attenuated palatable food self-administration (diluted vanilla Ensure), significantly reducing food rewards at 18 and 30 mg/kg PSNCBAM-1. PSNCBAM-1 did not affect conditioned place preference for 2 g/kg ethanol. These results suggest PSNCBAM-1 reduces ethanol-taking behavior via a nonspecific hypophagic effect and does not reduce the rewarding effects of ethanol.

Impacts of Unhealthy Behaviors on Mental Health among Public Health Residents: The PHRASI Study

Unhealthy behaviors (UBs) can affect mental health. The most impactful of these are alcohol abuse, sedentary behavior, and sleep disturbances. Since these UBs are not well explored in medical residents, this study aims to overcome this gap, focusing on outcomes such as depression and anxiety. The Public Health Residents' Anonymous Survey in Italy (PHRASI) is a nationwide cross-sectional study based on an 88-item questionnaire. UBs were explored through validated questionnaires: the Alcohol Use Disorders Identification Test-c (AUDIT-C), the International Physical Activity Questionnaire (IPAQ), and the Insomnia Severity Index (ISI). Depressive symptoms and anxiety were detected by Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7), respectively. Hierarchical cluster analysis described clusters using responses from the AUDIT-C, IPAQ, and ISI. A total of 375 participants were included in this study. Three distinct clusters (CL) were identified: CL1 was characterized by a moderate risk for alcohol abuse and high insomnia dissatisfaction, with a significantly higher frequency of depressive symptoms (46%, p < 0.001) and anxiety (53%, p < 0.001); CL2 had no risk for alcohol abuse, high sleep satisfaction, and better mental health profile, with the lowest prevalence of depressive symptoms (15%, p < 0.001); CL3 had the highest risk of alcohol abuse, the highest rate of physical activity (40%, p = 0.013), and the lowest prevalence of anxiety (27%, p < 0.001). Subjects belonging to CL1 required much more attention to prevent the worsening of mental outcomes. Interventions for promoting mental health should be addressed in all Public Health schools to create more sustainable working conditions.

Ethanol's impact on the brain: a neurobiological perspective on the mechanisms of memory impairment

Alcohol consumption is known to have detrimental effects on memory function, with various studies implicating ethanol in the impairment of cognitive processes related to memory retention and retrieval. This review aims to elucidate the complex neurobiological mechanisms underlying ethanol-induced memory impairment. Through a thorough search of existing literature using electronic databases, relevant articles focusing on the neurobiological mechanisms of ethanol on memory were identified and critically evaluated. This review focuses on the molecular and neural pathways through which ethanol exerts its effects on memory formation, consolidation, and recall processes. Key findings from the included studies shed light on the impact of ethanol on neurotransmitter systems, synaptic plasticity, and neuroinflammation in relation to memory impairment. This review contributes to a better understanding of the intricate mechanisms by which alcohol impairs memory function, offering insights for future research directions and the development of targeted interventions to alleviate these cognitive impairments.

Serotonin transporter knockdown relieves depression-like behavior and ethanol-induced CPP in mice after chronic social defeat stress

Patients with stress-triggered major depression disorders (MDD) can often seek comfort or temporary relief through alcohol consumption, as they may turn to it as a means of self-medication or coping with overwhelming emotions. The use of alcohol as a coping mechanism for stressful events can escalate, fostering a cycle where the temporary relief it provides from depression can deepen into alcohol dependence, exacerbating both conditions. Although, the specific mechanisms involved in stress-triggered alcohol dependence and MDD comorbidities are not well understood, a large body of literature suggests that the serotonin transporter (SERT) plays a critical role in these abnormalities. To further investigate this hypothesis, we used a lentiviral-mediated knockdown approach to examine the role of hippocampal SERT knockdown in social defeat stress-elicited depression like behavior and ethanol-induced place preference (CPP). The results showed that social defeat stress-pro depressant effects were reversed following SERT knockdown demonstrated by increased sucrose preference, shorter latency to feed in the novelty suppressed feeding test, and decreased immobility time in the tail suspension and forced swim tests. Moreover, and most importantly, social stress-induced ethanol-CPP acquisition and reinstatement were significantly reduced following hippocampal SERT knockdown using short hairpin RNA shRNA-expressing lentiviral vectors. Finally, we confirmed that SERT hippocampal mRNA expression correlated with measures of depression- and ethanol-related behaviors by Pearson's correlation analysis. Taken together, our data suggest that hippocampal serotoninergic system is involved in social stress-triggered mood disorders as well as in the acquisition and retrieval of ethanol contextual memory and that blockade of this transporter can decrease ethanol rewarding properties.

Addressing cortex dysregulation in youth through brain health check coaching and prophylactic brain development

The Carter Center has estimated that the addiction crisis in the United States (US), if continues to worsen at the same rate, may cost the country approximately 16 trillion dollars by 2030. In recent years, the well-being of youth has been compromised by not only the coronavirus disease 2019 pandemic but also the alarming global opioid crisis, particularly in the US. Each year, deadly opioid drugs claim hundreds of thousands of lives, contributing to an ever-rising death toll. In addition, maternal usage of opioids and other drugs during pregnancy could compromise the neurodevelopment of children. A high rate of DNA polymorphic antecedents compounds the occurrence of epigenetic insults involving methylation of specific essential genes related to normal brain function. These genetic antecedent insults affect healthy DNA and mRNA transcription, leading to a loss of proteins required for normal brain development and function in youth. Myelination in the frontal cortex, a process known to extend until the late 20s, delays the development of proficient executive function and decision-making abilities. Understanding this delay in brain development, along with the presence of potential high-risk antecedent polymorphic variants or alleles and generational epigenetics, provides a clear rationale for embracing the Brain Research Commission's suggestion to mimic fitness programs with an adaptable brain health check (BHC). Implementing the BHC within the educational systems in the US and other countries could serve as an effective initiative for proactive therapies aimed at reducing juvenile mental health problems and eventually criminal activities, addiction, and other behaviors associated with reward deficiency syndrome.

Inhibition of the Sodium-Calcium Exchanger Reverse Mode Activity Reduces Alcohol Consumption in Rats

Excessive and uncontrolled consumption of alcohol can cause alcohol use disorder (AUD), but its pharmacological mechanisms are not fully understood. Inhibiting the reverse mode activity of the sodium-calcium exchanger (NCX) can reduce the risk of alcohol withdrawal seizures, suggesting that NCX could play a role in controlling alcohol consumption. Here, we investigated how two potent inhibitors of NCX reverse mode activity, SN-6 (NCX1) and KB-R7943 (NCX3), affect voluntary alcohol consumption in adult male and female rats using the intermittent alcohol access two-bottle choice paradigm. Initially, animals were trained to drink 7.5% ethanol and water for four weeks before administering SN-6 and KB-R7934. Afterward, their alcohol intake, preference, and water intake were recorded 2 and 24 h after exposure to water and 7.5% ethanol. SN-6 significantly reduced alcohol consumption by 48% in male and 36% in female rats without affecting their water intake. Additionally, SN-6 significantly reduced alcohol preference in females by 27%. However, KB-R7943 reduced alcohol consumption by 42% in female rats and did not affect alcohol preference or water intake. These findings suggest that alcohol exposure increased NCX reverse activity, and targeting NCX1 could be an effective strategy for reducing alcohol consumption in subjects susceptible to withdrawal seizures.

Astrocytic GABAergic Regulation in Alcohol Use and Major Depressive Disorders

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system (CNS). Most GABAergic neurons synthesize GABA from glutamate and release it in the synaptic cleft in the CNS. However, astrocytes can also synthesize and release GABA, activating GABA receptors in the neighboring neurons in physiological and pathological conditions. As the primary homeostatic glial cells in the brain, astrocytes play a crucial role in regulating GABA homeostasis and synaptic neurotransmission. Accumulating evidence demonstrates that astrocytic GABA dysregulation is implicated in psychiatric disorders, including alcohol use disorder (AUD) and major depressive disorder (MDD), the most prevalent co-occurring psychiatric disorders. Several current medications and emerging pharmacological agents targeting GABA levels are in clinical trials for treating AUD and MDD. This review offers a concise summary of the role of astrocytic GABA regulation in AUD and MDD. We also provide an overview of the current understanding and areas of debate regarding the mechanisms by which astrocytes regulate GABA in the CNS and their potential significance in the molecular basis of AUD and MDD, paving the way toward future research directions and potential therapeutic target areas within this field.

Benzydamine hydrochloride ameliorates ethanol-induced inflammation in RAW 264.7 macrophages by stabilizing redox homeostasis

Objective:

To evaluate the protective effect of benzydamine hydrochloride against ethanol-induced oxidative stress and inflammation in RAW 264.7 macrophages.

Methods:

RAW 264.7 macrophages were treated with ethanol (100 mM) and benzydamine hydrochloride (7.5 μM). The inflammatory status was confirmed by measuring pro-(TNF-α and IL-6) and anti-inflammatory (IL-10) cytokines through ELISA and RT-PCR assays. Reactive oxygen species generation and mitochondrial membrane potential were investigated to study the protective role of benzydamine hydrochloride against ethanol-induced oxidative stress. Apoptosis detection was also investigated using flow cytometry and acridine orange/ethidium bromide staining.

Results:

Benzydamine hydrochloride significantly decreased the secretion of TNF-α and IL-6, as well as the generation of reactive oxygen species inside the cells, thereby stabilizing the mitochondrial membrane potential and reducing DNA fragmentation. The ethanol-induced cellular necrosis was also reversed by the administration of benzydamine hydrochloride.

Conclusions:

Benzydamine hydrochloride ameliorates ethanol-induced cell apoptosis and inflammation in RAW macrophages.

The Roles of Endogenous D2R Dopamine and μ-opioid Receptors of the Brain in Alcohol use Disorder

Alcohol use disorder (AUD) affects millions of people worldwide. It is characterized by a strong physiological and psychological craving to consume large amounts of alcohol despite adverse consequences. Alcohol use disorder carries a large health and economic burden on society. Despite its prevalence, AUD is still severely undertreated. The precise molecular mechanisms of how alcohol addiction forms are yet unknown. However, previous studies on animal models show that along with the μ-opioid receptors, the D2R dopamine receptors may also be involved in alcohol craving and reward pathways. Currently, there is a limited number of treatment strategies for alcohol use disorder, which include several medications and therapy. By understanding the limitations of current treatment options and exploring new potential targets, it could be possible to find more effective ways of treating AUD in the future.

Molecular mechanisms of alcohol's effects on the human body: A review and update

Alcohol consumption has been linked to numerous negative health outcomes although it has some beneficial effects on moderate dosages, the most severe of which being alcohol-induced hepatitis. The number of people dying from this liver illness has been shown to climb steadily over time, and its prevalence has been increasing. Researchers have found that alcohol consumption primarily affects the brain, leading to a wide range of neurological and psychological diseases. High-alcohol-consumption addicts not only experienced seizures, but also ataxia, aggression, social anxiety, and variceal hemorrhage that ultimately resulted in death, ascites, and schizophrenia. Drugs treating this liver condition are limited and can cause serious side effects like depression. Serine-threonine kinases, cAMP protein kinases, protein kinase C, ERK, RACK 1, Homer 2, and more have all been observed to have their signaling pathways disrupted by alcohol, and alcohol has also been linked to epigenetic changes. In addition, alcohol consumption induces dysbiosis by changing the composition of the microbiome found in the gastrointestinal tract. Although more studies are needed, those that have been done suggest that probiotics aid in keeping the various microbiota concentrations stable. It has been argued that reducing one's alcohol intake may seem less harmful because excessive drinking is a lifestyle disorder.

Alcohol Cue Processing in Co-Occurring Bipolar Disorder and Alcohol Use Disorder

Importance

Reward circuitry dysfunction is a candidate mechanism of co-occurring bipolar disorder and alcohol use disorder (BD + AUD) that remains understudied. This functional magnetic resonance imaging (fMRI) research represents the first evaluation of alcohol cue reward processing in BD + AUD.

Objective

To determine how alcohol cue processing in individuals with BD + AUD may be distinct from that of individuals with AUD or BD alone.

Design, Setting, and Participants

This cross-sectional case-control study (April 2013-June 2018) followed a 2 × 2 factorial design and included individuals with BD + AUD, AUD alone, BD alone, and healthy controls. A well-validated visual alcohol cue reactivity fMRI paradigm was administered to eligible participants following their demonstration of 1 week or more of abstinence from alcohol and drugs assessed via serial biomarker testing. Study procedures were completed at the Medical University of South Carolina. Analysis took place between June and August 2022.

Main Outcomes and Measures

Past-week mood symptoms were rated by clinicians using the Montgomery-Åsberg Depression Rating Scale and Young Mania Rating Scale. The Alcohol Dependence Scale, Obsessive-Compulsive Drinking Scale, and Barratt Impulsiveness Scale were included questionnaires. Functional MRI whole-brain data were analyzed along with percent signal change within a priori regions of interest located in the ventral striatum, dorsal striatum, and ventromedial prefrontal cortex. Exploratory analyses of associations between cue reactivity and select behavioral correlates (alcohol craving, impulsivity, maximum number of alcohol drinks on a single occasion, and days since last alcohol drink) were also performed.

Results

Of 112 participants, 28 (25.0%) had BD + AUD, 26 (23.2%) had AUD alone, 31 (27.7%) had BD alone, and 27 (24.1%) were healthy controls. The mean (SD) age was 38.7 (11.6) years, 50 (45.5%) were female, 33 (30%) were smokers, and 37 (34.9%) reported recent alcohol consumption. Whole-brain analyses revealed a BD × AUD interaction (F = 10.64; P = .001; η2 = 0.09) within a cluster spanning portions of the right inferior frontal gyrus and insula. Region of interest analyses revealed a main association of BD (F = 8.02; P = .006; η2 = 0.07) within the dorsal striatum. In each instance, individuals with BD + AUD exhibited reduced activation compared with all other groups who did not significantly differ from one another. These hypoactivations were associated with increased impulsivity and obsessive-compulsive alcohol craving exclusively among individuals with BD + AUD.

Conclusion and Relevance

The findings of this study suggest conceptualizing reward dysfunction in BD + AUD by the potential interaction between blunted reward responsivity and deficient inhibitory control may help guide treatment development strategies. To this end, reduced right inferior frontal gyrus and insula alcohol cue reactivity represents a novel candidate biomarker of BD + AUD that may respond to pharmacological interventions targeting impulsivity-related neural mechanisms for improved executive control.

GABAergic signaling in alcohol use disorder and withdrawal: pathological involvement and therapeutic potential

Alcohol is one of the most widely used substances. Alcohol use accounts for 5.1% of the global disease burden, contributes substantially to societal and economic costs, and leads to approximately 3 million global deaths yearly. Alcohol use disorder (AUD) includes various drinking behavior patterns that lead to short-term or long-lasting effects on health. Ethanol, the main psychoactive molecule acting in alcoholic beverages, directly impacts the GABAergic system, contributing to GABAergic dysregulations that vary depending on the intensity and duration of alcohol consumption. A small number of interventions have been developed that target the GABAergic system, but there are promising future therapeutic avenues to explore. This review provides an overview of the impact of alcohol on the GABAergic system, the current interventions available for AUD that target the GABAergic system, and the novel interventions being explored that in the future could be included among first-line therapies for the treatment of AUD.

Emotional Processing and Maltreatment During Childhood as Factors of Vulnerability to Alcohol Abuse in Young Adults

Different studies suggest a strong association between childhood abuse and alcohol use disorders (AUDs). The modulation of the startle response has been used to assess emotional processing in AUDs. The main objective of the study was to investigate the startle reflex responses to different stimuli in young adults with varying types of childhood abuse in comparison with a control group according to their current alcohol consumption and the presence of a parent with alcohol dependence or not. A clinical sample of 606 adolescents, divided into five groups: no abuse, physical neglect, emotional neglect, emotional abuse, physical abuse, and sexual abuse, were assessed on their pattern of alcohol consumption and their family history of alcoholism. The proportion of participants with at least one alcohol-dependent parent was higher in all types of abuse. The proportion of heavy drinkers and alcohol-dependent participants was higher in the groups with physical neglect and sexual abuse. Heavy drinkers and alcohol dependents showed a lower startle reflex response to emotional pictures, especially alcohol-related ones. Adolescents exposed to physical and sexual abuse during childhood showed a mitigated startle response to appetitive and alcohol-related pictures. The results of this exploratory study reveal that childhood maltreatment modulates emotional processing to alcohol-related stimuli during adolescence. The evaluation of these patients’ startle response could be considered a prognostic biomarker for establishing personalized preventive strategies during the adolescent stage to avoid, to a large extent, future problems derived from alcohol consumption.

Functional and Structural Brain Abnormalities and Clinical Characteristics of Male Patients with Alcohol Dependence

Even though many previous studies have reported structural or functional brain abnormalities in patients with alcohol dependence (ADPs), studies observing the structural and functional abnormalities associated with the clinical characteristics of ADPs utilizing a multimodal approach are still scarce. The aim of this study was to demonstrate structural and functional brain abnormalities and their association with the clinical characteristics of alcoholism in male ADPs. Fifteen healthy male controls (HCs) and 15 male ADPs who had been diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders 5 criteria underwent T1-weighted imaging and resting-state functional magnetic resonance imaging (MRI) scans. The MRI data were postprocessed using statistical parametric mapping for structural analysis and CONN-fMRI functional connectivity (FC) tools for functional analysis. In comparison with male HCs, male ADPs were characterized by significantly reduced volumes of the white matter in the left globus pallidus (GP) (p-FDR < 0.05). This region affected the altered resting-state FC patterns in male ADPs. Interestingly, an abnormal FC in the precuneus and its positive correlation with the alcohol-use disorder identification test score were observed in ADPs (r = 0.546, p = 0.036). Based on the observations, it could be concluded that the GP serves as a neural marker that impacts abnormal functional networks in men with alcohol dependence. These findings have important clinical implications as they provide insights into the neural mechanism underlying the anatomical, functional, and clinical features of alcoholism.

Neurotensin and Alcohol Use Disorders: Towards a Pharmacological Treatment

Harmful alcohol use is responsible for a group of disorders collectively named alcohol use disorders (AUDs), according to the DSM-5 classification. The damage induced by alcohol depends on the amount, time, and consumption patterns (continuous and heavy episodic drinking). It affects individual global well-being and social and familial environments with variable impact. Alcohol addiction manifests with different degrees of organ and mental health detriment for the individual, exhibiting two main traits: compulsive drinking and negative emotional states occurring at withdrawal, frequently causing relapse episodes. Numerous individual and living conditions, including the concomitant use of other psychoactive substances, lie in the complexity of AUD. Ethanol and its metabolites directly impact the tissues and may cause local damage or alter the homeostasis of brain neurotransmission, immunity scaffolding, or cell repair biochemical pathways. Brain modulator and neurotransmitter-assembled neurocircuitries govern reward, reinforcement, social interaction, and consumption of alcohol behaviors in an intertwined manner. Experimental evidence supports the participation of neurotensin (NT) in preclinical models of alcohol addiction. For example, NT neurons in the central nucleus of the amygdala projecting to the parabrachial nucleus strengthen alcohol consumption and preference. In addition, the levels of NT in the frontal cortex were found to be lower in rats bred to prefer alcohol to water in a free alcohol-water choice compared to wild-type animals. NT receptors 1 and 2 seem to be involved in alcohol consumption and alcohol effects in several models of knockout mice. This review aims to present an updated picture of the role of NT systems in alcohol addiction and the possible use of nonpeptide ligands modulating the activity of the NT system, applied to experimental animal models of harmful drinking behavior mimicking alcohol addiction leading to health ruin in humans.

Differential Effects of Chronic Ethanol Use on Mouse Neuronal and Astroglial Metabolic Activity

Chronic alcohol use disorder, a major risk factor for the development of neuropsychiatric disorders including addiction to other substances, is associated with several neuropathology including perturbed neuronal and glial activities in the brain. It affects carbon metabolism in specific brain regions, and perturbs neuro-metabolite homeostasis in neuronal and glial cells. Alcohol induced changes in the brain neurochemical profile accompany the negative emotional state associated with dysregulated reward and sensitized stress response to withdrawal. However, the underlying alterations in neuro-astroglial activities and neurochemical dysregulations in brain regions after chronic alcohol use are poorly understood. This study evaluates the impact of chronic ethanol use on the regional neuro-astroglial metabolic activity using ¹H-[¹³C]-NMR spectroscopy in conjunction with infusion of [1,6-¹³C₂]glucose and sodium [2-¹³C]acetate, respectively, after 48 h of abstinence. Besides establishing detailed ¹³C labeling of neuro-metabolites in a brain region-specific manner, our results show chronic ethanol induced-cognitive deficits along with a reduction in total glucose oxidation rates in the hippocampus and striatum. Furthermore, using [2-¹³C]acetate infusion, we showed an alcohol-induced increase in astroglial metabolic activity in the hippocampus and prefrontal cortex. Interestingly, increased astroglia activity in the hippocampus and prefrontal cortex was associated with a differential expression of monocarboxylic acid transporters that are regulating acetate uptake and metabolism in the brain.

Advances in the development of phosphodiesterase 7 inhibitors

Phosphodiesterase 7 (PDE7) specifically hydrolyzes cyclic adenosine monophosphate (cAMP), a second messenger that plays essential roles in cell signaling and physiological processes. Many PDE7 inhibitors used to investigate the role of PDE7 have displayed efficacy in the treatment of a wide range of diseases, such as asthma and central nervous system (CNS) disorders. Although PDE7 inhibitors are developed more slowly than PDE4 inhibitors, there is increasing recognition of PDE7 inhibitors as potential therapeutics for no nausea and vomiting secondary. Herein, we summarized the advances in PDE7 inhibitors over the past decade, focusing on their crystal structures, key pharmacophores, subfamily selectivity, and therapeutic potential. Hopefully, this summary will lead to a better understanding of PDE7 inhibitors and provide strategies for developing novel therapies targeting PDE7.

Association of Functional Polymorphism in TPH2 Gene with Alcohol Dependence and Personality Traits: Study in Cloninger's Type I and Type II Alcohol-Dependent Inpatients

Alcohol dependence (AD) is a complex disorder with a poorly understood etiology. In this study, we investigated the relationship between genetic variation in the TPH2 gene, which encodes the enzyme responsible for serotonin synthesis in the brain, and both AD and personality traits, with attention to Cloninger's types of AD. The study included 373 healthy control subjects, 206 inpatients with type I AD, and 110 inpatients with type II AD. All subjects were genotyped for the functional polymorphism rs4290270 in the TPH2 gene, and AD patients completed the Tridimensional Personality Questionnaire (TPQ). The AA genotype and the A allele of the rs4290270 polymorphism were more frequent in both patient groups compared with the control group. In addition, a negative association was found between the number of A alleles and TPQ scores for harm avoidance in patients with type II, but not type I, AD. These results support the involvement of genetic variations of the serotonergic system in the pathogenesis of AD, especially type II AD. They also suggest that in a subset of patients, genetic variation of TPH2 could potentially influence the development of AD by affecting the personality trait of harm avoidance.

Alterations and correlations of gut microbiota, fecal, and serum metabolome characteristics in a rat model of alcohol use disorder

Background

Growing evidence suggests the gut microbiota and metabolites in serum or fecal may play a key role in the process of alcohol use disorder (AUD). However, the correlations of gut microbiota and metabolites in both feces and serum in AUD subjects are not well understood.

Methods

We established a rat model of AUD by a chronic intermittent ethanol voluntary drinking procedure, then the AUD syndromes, the gut microbiota, metabolomic profiling in feces and serum of the rats were examined, and correlations between gut microbiota and metabolites were analyzed.

Results

Ethanol intake preference increased and maintained at a high level in experimental rats. Anxiety-like behaviors was observed by open field test and elevated plus maze test after ethanol withdraw, indicating that the AUD rat model was successfully developed. The full length 16S rRNA gene sequencing showed AUD significantly changed the β-diversity of gut microbial communities, and significantly decreased the microbial diversity but did not distinctly impact the microbial richness. Microbiota composition significantly changed in AUD rats, such as the abundance of Romboutsia and Turicibacter were significantly increased, whereas uncultured_bacterium_o_Mollicutes_RF39 was decreased. In addition, the untargeted metabolome analysis revealed that many metabolites in both feces and serum were altered in the AUD rats, especially involved in sphingolipid metabolism and glycerophospholipid metabolism pathways. Finally, multiple correlations among AUD behavior, gut microbiota and co-changed metabolites were identified, and the metabolites were directly correlated with the gut microbiota and alcohol preference.

Conclusion

The altered metabolites in feces and serum are important links between the gut microbiota dysbiosis and alcohol preference in AUD rats, and the altered gut microbiota and metabolites can be potentially new targets for treating AUD.

Population Health Metrics During the Early Stages of the COVID-19 Pandemic: Correlative Pilot Study

BACKGROUND

COVID-19 has caused nearly 1 million deaths in the United States, not to mention job losses, business and school closures, stay-at-home orders, and mask mandates. Many people have suffered increased anxiety and depression since the pandemic began. Not only have mental health symptoms become more prevalent, but alcohol consumption has also increased during this time. Helplines offer important insight into both physical and mental wellness of a population by offering immediate, anonymous, cheap, and accessible resources for health and substance use disorders (SUD) that was unobstructed by many of the mandates of the pandemic. Further, the pandemic also launched the use of wastewater surveillance, which has the potential for tracking not only population infections but also consumption of substances such as alcohol.

OBJECTIVE

This study assessed the feasibility of using multiple public surveillance metrics, such as helpline calls, COVID-19 cases, and alcohol metabolites in wastewater, to better understand the need for interventions or public health programs in the time of a public health emergency.

METHODS

Ethanol metabolites were analyzed from wastewater collected twice weekly from September 29 to December 4, 2020, in a Midwestern state. Calls made to the helpline regarding housing, health care, and mental health/SUD were correlated with ethanol metabolites analyzed from wastewater samples, as well as the number of COVID-19 cases during the sampling period.

RESULTS

Correlations were observed between COVID-19 cases and helpline calls regarding housing and health care needs. No correlation was observed between the number of COVID-19 cases and mental health/SUD calls. COVID-19 cases on Tuesdays were correlated with the alcohol metabolite ethyl glucuronide (EtG). Finally, EtG levels were negatively associated with mental health/SUD helpline calls.

CONCLUSIONS

Although helpline calls provided critical services for health care and housing-related concerns early in the pandemic, evidence suggests helpline calls for mental health/SUD-related concerns were unrelated to COVID-19 metrics. Instead, COVID metrics were associated with alcohol metabolites in wastewater. Although this research was formative, with continued and expanded monitoring of population metrics, such as helpline usage, COVID-19 metrics, and wastewater, strategies can be implemented to create precision programs to address the needs of the population.