A biological framework for emotional dysregulation in alcohol misuse: from gut to brain

The Role of Diet and the Gut Microbiota in Reactive Aggression and Adult ADHD-An Exploratory Analysis

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition, of-ten persistent into adulthood and accompanied by reactive aggression. Associations of diet and the gut-microbiome with ADHD as well as emotional behaviors suggest potential clinical rele-vance of both. However, studies on diet and the gut-microbiome in human reactive aggression are lacking, and should investigate the interaction between diet and the gut-microbiome leading to behavioral changes to assess their potential clinical relevance. In this study, we investigated the interaction of diet and gut-microbiota with adult ADHD and reactive aggression in 77 adults with ADHD and 76 neurotypical individuals. We studied the relationships of ADHD and reactive ag-gression with dietary patterns, bacterial community and taxonomic differences of 16S-sequenced fecal microbiome samples, and potential mediating effects of bacterial genus abundance on signifi-cant diet-behavior associations. The key findings include: (1) An association of high-energy intake with reactive aggeression scores (pFDR = 4.01 × 10-02); (2) Significant associations of several genera with either reactive aggression or ADHD diagnosis with no overlap; and (3) No significant mediation effects of the selected genera on the association of reactive aggression with the high-energy diet. Our results suggest that diet and the microbiome are linked to reactive aggression and/or ADHD individually, and highlight the need to further study the way diet and the gut-microbiome inter-act.

The gut-brain axis in individuals with alcohol use disorder: An exploratory study of associations among clinical symptoms, brain morphometry, and the gut microbiome

BACKGROUND

Alcohol use disorder (AUD) is commonly associated with distressing psychological symptoms. Pathologic changes associated with AUD have been described in both the gut microbiome and brain, but the mechanisms underlying gut-brain signaling in individuals with AUD are unknown. This study examined associations among the gut microbiome, brain morphometry, and clinical symptoms in treatment-seeking individuals with AUD.

METHODS

We performed a secondary analysis of data collected during inpatient treatment for AUD in subjects who provided gut microbiome samples and had structural brain magnetic resonance imaging (MRI; n = 16). Shotgun metagenomics sequencing was performed, and the morphometry of brain regions of interest was calculated. Clinical symptom severity was quantified using validated instruments. Gut-brain modules (GBMs) used to infer neuroactive signaling potential from the gut microbiome were generated in addition to microbiome features (e.g., alpha diversity and bacterial taxa abundance). Bivariate correlations were performed between MRI and clinical features, microbiome and clinical features, and MRI and microbiome features.

RESULTS

Amygdala volume was significantly associated with alpha diversity and the abundance of several bacteria including taxa classified to Blautia, Ruminococcus, Bacteroides, and Phocaeicola. There were moderate associations between amygdala volume and GBMs, including butyrate synthesis I, glutamate synthesis I, and GABA synthesis I & II, but these relationships were not significant after false discovery rate (FDR) correction. Other bacterial taxa with shared associations to MRI features and clinical symptoms included Escherichia coli and Prevotella copri.

CONCLUSIONS

We identified gut microbiome features associated with MRI morphometry and AUD-associated symptom severity. Given the small sample size and bivariate associations performed, these results require confirmation in larger samples and controls to provide meaningful clinical inferences. Nevertheless, these results will inform targeted future research on the role of the gut microbiome in gut-brain communication and how signaling may be altered in patients with AUD.

Alcohol use disorder as a moderator of the relationship between posttraumatic stress disorder and suicidality among military personnel

BACKGROUND

Alcohol use disorder (AUD), posttraumatic stress disorder (PTSD), and suicide are substantial public health concerns among military service members, yet the nature of their relationships is not well understood. Here, we tested the hypothesis that AUD moderates the relationship between PTSD symptom severity and suicidal ideation.

METHODS

This secondary analysis uses data collected at baseline for a randomized clinical trial. The sample consists of 160 active-duty service members from three service branches (Army, Air Force, and Navy). All participants met diagnostic criteria for PTSD and were not engaged in evidence-based PTSD treatment at the time of enrollment. Zero-inflated Poisson generalized linear regression models were used to test the associations of PTSD and AUD symptom severity with the presence and severity of suicidal ideation.

RESULTS

Findings suggest that AUD symptom severity moderates (i.e., amplifies) the relationship between PTSD symptoms and severity of suicidal ideation among military personnel with untreated PTSD. Among service members with mild or absent AUD, we found no significant association between PTSD symptoms and the severity of suicidal ideation. However, when AUD severity was average (i.e., sample mean) or high (mean + 1SD), PTSD symptoms were significantly positively associated with the severity of suicidal ideation.

CONCLUSIONS

This study highlights the importance of assessing AUD and PTSD as a part of suicide risk evaluations of veterans. The results also provide strong support for the maintenance and further development in the military health system of treatment programs that simultaneously address AUD and PTSD comorbidity.

A Narrative Review of the Efficacy of Interventions for Emotional Dysregulation, and Underlying Bio-Psycho-Social Factors

In this narrative, comprehensive, and updated review of the literature, we summarize evidence about the effectiveness of interventions aimed at reducing emotion dysregulation and improving emotion regulation in children, adolescents, and adults. After introducing emotion dysregulation and emotion regulation from a theoretical standpoint, we discuss the factors commonly associated with emotion regulation, including neurobiological and neuropsychological mechanisms, and the role of childhood adverse experiences and psycho-social factors in the onset of emotion dysregulation. We then present evidence about pharmacological and non-pharmacological interventions aiming at improving emotion dysregulation and promoting emotion regulation across the lifespan. Although our review was not intended as a traditional systematic review, and the search was only restricted to systematic reviews and meta-analyses, we highlighted important implications and provided recommendations for clinical practice and future research in this field.

Polysaccharides from Eucommia ulmoides Oliv. Leaves Alleviate Acute Alcoholic Liver Injury by Modulating the Microbiota-Gut-Liver Axis in Mice

The interplay among gut microbiota, intestines, and liver is crucial in preventing acute alcoholic liver injury. In this study, the hepatoprotective potential of polysaccharides from Eucommia ulmoides Oliv. leaves (EULP) on acute alcoholic liver injury in Kunming male mice was investigated. The structural features suggested that the EULP appeared as a heterogeneous mixture of polysaccharides with a molecular weight of 186132 Da. A 14-day pretreatment of EULP ameliorated acute alcoholic-induced hepatic inflam mation (TNF-α, IL-6, and IL-10), oxidative stress (GSH, SOD, and T-AOC), and liver damage (ALT and AST) via enhancing intestinal barrier (Occludin, Claudin 1, and ZO-1) and modulating microbiome, which subsequently inhibiting endotoxemia and balancing the homeostasis of the gut-liver axis. EULP restored the composition of intestinal flora with an increase in the relative abundance of Lactobacillaceae and a decrease in Lachnospiraceae and Verrucomicrobiaceae. Notably, prolonged EULP pretreatment (14 days) but no single gavage of EULP achieved excellent hepatoprotection. These findings endorsed the potential of EULP as a functional food for mitigating acute alcoholic-induce d liver damage, attributed to its anti-inflammatory, antioxidant, and prebiotic properties facilitated by the microbiota-gut-liver axis.

Neuroimaging and Brain-Based Markers Identifying Neurobiological Markers Associated With Criminal Behaviour, Personality Disorders, and Mental Health: A Narrative Review

We begin the review by pointing to the common stigma associated with mental health issues, which often derives from a lack of understanding or incomplete knowledge. Neurobiological research provides us with a new lens to help challenge and dispel common assumptions and misunderstandings and gives an understanding of sexual behaviours that influence society. As such, it generates substantial evidence for the structural and functional asymmetry of the brains of individuals with mental disorders. However, this type of representation poses many challenges to traditional thinking and constantly provokes change in perspective and empathy towards those individuals. In the review, we go deeper into the effects of neurobiological findings on understanding criminal behaviours and personality disorders, looking further beyond behavioural health. These problems, which were once mainly discussed as moral ones or viewed from the perspective of character flaws, are analysed today through neurological considerations pointing to their complexity. When the root of bipolar disorder is revealed to be neurological, society will react with more information and understanding, hence reducing the stigmatisation and discrimination meted out to people with these problems. At a macro level, findings from neurobiology affect society in ways that go beyond individuals; social attitudes, laws, and policies about the services rendered are influenced. Operating as a catalyst within the community, neurobiological research helps to initiate social change through the creation of an informed, understanding public forum. Thus, it creates broader value for those dealing with behavioural and mental health challenges. The first and most important question of this narrative review is focused on identifying identifiable neurobiological markers that are closely related to criminal conduct, personality disorders, and mental health disorders. Through this review, we aim to present detailed insights into the neurological foundations that anchor these phenomena via a narrative analysis of contemporary literature. The potential implications are finding problems early to apply specific treatment and learning an advanced strategy for social attitudes. This will promote a more humanistic approach based on adequate information on the behavioural and mental health issues involved.

Fecal microbiota transplantation repairs intestinal permeability and regulates the expression of 5-HT to influence alcohol-induced depression-like behaviors in C57BL/6J mice

The epidemic of alcohol abuse affects millions of people worldwide. Relevant evidence supports the notion that the gut microbiota (GM) plays a crucial role in central nervous system (CNS) function, and its composition undergoes changes following alcohol consumption. Therefore, the purpose of this study was to investigate the effect of reconstructing the gut microbiota by fecal microbiota transplantation (FMT) on alcohol dependence. Here, we established an alcohol dependence model with C57BL/6J mice and proved that FMT treatment improved anxiety-like behavior and alcohol-seeking behavior in alcohol-dependent mice. Additionally, we found that the expression of the intestinal intercellular tight junction structure proteins ZO-1 and occludin was significantly increased after FMT. FMT repaired intestinal permeability in alcohol-dependent mice and decreased the levels of lipopolysaccharide (LPS) and proinflammatory factors. Moreover, the serotonin (5-hydroxytryptamine, 5-HT) content was significantly increased in alcohol-dependent mouse intestinal and brain tissues after receiving the fecal microbiome from healthy mice. 16S rRNA sequencing demonstrated that FMT markedly reshaped the composition of the gut microbiota and elicited changes in the intestinal barrier and 5-HT levels. Collectively, our results revealed that FMT has a palliative effect on alcohol dependence and explored the underlying mechanisms, which provides new strategies for the treatment of alcohol dependence.

Intestinal microbiome dysbiosis in alcohol-dependent patients and its effect on rat behaviors

IMPORTANCE

Intestinal microbiome dysbiosis is associated with psychiatric disease through the "microbiota-gut-brain" axis. Here, we revealed that there was obvious intestinal microbiome (including bacterial and fungal) dysbiosis in alcohol-dependent patients. Alcohol consumption seriously disturbs the gut equilibrium between bacteria and fungi, reduces the interactions among bacterial-fungal trans-kingdom, and increases intestinal permeability. Gut microbiota should be considered as a whole to study the development of alcohol dependence. The gut microbiome of alcohol-dependent patients increased the anxiety- and depression-like behavior in rats. The gut microbiota dysbiosis may promote the development of alcohol dependence by regulating the endogenous cholecystokinin (CCK) and related receptors. Hence, regulating the balance of gut microbiota and the endogenous CCK may be a potential strategy for reducing the risk of relapse in alcohol addiction patients.

Gut feelings: associations of emotions and emotion regulation with the gut microbiome in women

BACKGROUND

Accumulating evidence suggests that positive and negative emotions, as well as emotion regulation, play key roles in human health and disease. Recent work has shown the gut microbiome is important in modulating mental and physical health through the gut-brain axis. Yet, its association with emotions and emotion regulation are understudied. Here we examined whether positive and negative emotions, as well as two emotion regulation strategies (i.e. cognitive reappraisal and suppression), were associated with the gut microbiome composition and functional pathways in healthy women.

METHODS

Participants were from the Mind-Body Study (N = 206, mean age = 61), a sub-study of the Nurses' Health Study II cohort. In 2013, participants completed measures of emotion-related factors. Two pairs of stool samples were collected, 6 months apart, 3 months after emotion-related factors measures were completed. Analyses examined associations of emotion-related factors with gut microbial diversity, overall microbiome structure, and specific species/pathways and adjusted for relevant covariates.

RESULTS

Alpha diversity was negatively associated with suppression. In multivariate analysis, positive emotions were inversely associated with the relative abundance of Firmicutes bacterium CAG 94 and Ruminococcaceae bacterium D16, while negative emotions were directly correlated with the relative abundance of these same species. At the metabolic pathway level, negative emotions were inversely related to the biosynthesis of pantothenate, coenzyme A, and adenosine.

CONCLUSIONS

These findings offer human evidence supporting linkages of emotions and related regulatory processes with the gut microbiome and highlight the importance of incorporating the gut microbiome in our understanding of emotion-related factors and their associations with physical health.

Gut microbiota in alcohol-related liver disease: pathophysiology and gut-brain cross talk

Alcohol-related liver disease (ALD) from excessive alcohol intake has a unique gut microbiota profile. The disease progression-free survival in ALD patients has been associated with the degree of gut dysbiosis. The vicious cycles between gut dysbiosis and the disease progression in ALD including: an increase of acetaldehyde production and bile acid secretion, impaired gut barrier, enrichment of circulating microbiota, toxicities of microbiota metabolites, a cascade of pro-inflammatory chemokines or cytokines, and augmentation in the generation of reactive oxygen species. The aforementioned pathophysiology process plays an important role in different disease stages with a spectrum of alcohol hepatitis, ALD cirrhosis, neurological dysfunction, and hepatocellular carcinoma. This review aims to illustrate the pathophysiology of gut microbiota and clarify the gut-brain crosstalk in ALD, which may provide the opportunity of identifying target points for future therapeutic intervention in ALD.

IL-6, but not TNF-α, response to alcohol cues and acute consumption associated with neural cue reactivity, craving, and future drinking in binge drinkers

Objective and design

Preclinical studies suggest learned immune system responses to alcohol cues and consumption may contribute to alcohol's pharmacodynamic properties and/or Alcohol Use Disorder (AUD) pathogenesis. Mechanistically, these immune alterations may be associated with increased craving and alcohol consumption, both acutely and over time. We sought to characterize this relationship in a randomized, counter-balanced, crossover neuroimaging experiment which took place between June 2020-November 2021.

Methods

Thirty-three binge drinkers (BD) and 31 non-binge, social drinkers (SD), matched for demographic and psychological variables, were exposed to alcohol cues and water cues in two separate 7 T functional magnetic resonance imaging (fMRI) scans. Each scan was followed by the Alcohol Taste Test (ATT) of implicit motivation for acute alcohol. Craving measures and blood cytokine levels were collected repeatedly during and after scanning to examine the effects of alcohol cues and alcohol consumption on craving levels, Tumor necrosis factor alpha (TNF-α), and Interleukin 6 (IL-6) levels. A post-experiment one-month prospective measurement of participants' "real world" drinking behavior was performed to approximate chronic effects.

Results

BD demonstrated significantly higher peak craving and IL-6 levels than SD in response to alcohol cues and relative to water cues. Ventromedial Prefrontal Cortex (VmPFC) signal change in the alcohol-water contrast positively related to alcohol cue condition craving and IL-6 levels, relative to water cue condition craving and IL-6 levels, in BD only. Additionally, peak craving and IL-6 levels were each independently related to ATT alcohol consumption and the number of drinks consumed in the next month for BD, again after controlling for craving and IL-6 repones to water cues. However, TNF-α release in the alcohol cue condition was not related to craving, neural activation, IL-6 levels, immediate and future alcohol consumption in either group after controlling for water cue condition responses.

Conclusions

In sum, BD show greater craving and IL-6 release in the alcohol cue condition than SD, both of which were associated with prefrontal cue reactivity, immediate alcohol consumption, and future alcohol consumption over the subsequent 30 days. Alcohol associated immune changes and craving effects on drinking behavior may be independent of one another or may be indicative of a common pathway by which immune changes in BD could influence motivation to consume alcohol.

Trial registration

Clinical Trials NCT04412824.

Mediated and moderated associations between cumulative lifetime stressor exposure, emotional dysregulation, impulsivity, and lifetime alcohol use: A cross-sectional scoping study of UK drinkers

Stress, trait impulsivity, and emotional dysregulation are independent predictors of alcohol use and misuse, but little is known about the potential mechanisms that link these risk factors together. To address this issue, we carried out an exploratory cross-sectional study, on UK-based participants. Our preregistered, hypothesised theoretical framework was that emotional dysregulation mediates the association between cumulative lifetime stressor exposure and lifetime alcohol use. We also hypothesised that heightened impulsivity would strengthen these relations. As hypothesised, emotional dysregulation fully mediated the relation between cumulative lifetime stressor exposure and lifetime alcohol use. Several facets of impulsivity moderated these associations. For example, as levels of negative urgency increased, the associations between cumulative lifetime stressor exposure and emotional dysregulation, emotional dysregulation and lifetime alcohol use, and lifetime stress exposure and lifetime alcohol use, via emotional dysregulation, strengthened. These preliminary findings propose a theoretically framed model which integrates several prominent risk-factors for alcohol misuse, extending prior research and generating interesting and novel lines of enquiry for longitudinal and cross-cultural analyses. The findings also highlight the potential clinical utility of screening for lifetime stress exposure while tailoring personalised treatment interventions.

Intergenerational and early life associations of the gut microbiome and stress-related symptomatology among Black American mothers and children

Recent evidence suggests that maternal childhood adversity may have an intergenerational impact, with children of adversity-exposed mothers exhibiting elevated symptoms of psychopathology. At the same time, many children demonstrate resilience to these intergenerational effects. Among the variety of factors that likely contribute to resilience, the composition of the gut microbiome may play a role in buffering the negative impacts of trauma and stress. The current prospective cohort study tested the novel hypothesis that offspring gut microbiome composition is a potential moderator in the relationship between maternal exposure to childhood adversity and offspring symptomatology (i.e., internalizing, externalizing, and posttraumatic stress symptoms). Maternal childhood adversity was self-reported during pregnancy via the Childhood Trauma Questionnaire and Adverse Childhood Experiences (ACEs) survey, and offspring symptomatology was assessed with the Child Behavior Checklist/1.5-5 when offspring were 2-4 years old. Offspring fecal samples were collected between these timepoints (i.e., during 6- to 24-month follow-up visits) for microbiome sequencing. Results indicated that maternal ACEs and the relative abundances of Bifidobacterium, Lactobacillus, and Prevotella were associated with offspring symptomatology. However, there was little evidence that microbial abundance moderated the association between maternal adversity and offspring symptoms. Overall, these findings further our understanding of how the gut microbiome associates with psychopathology, and informs future studies aimed at targeting modifiable factors that may buffer the intergenerational effects of childhood adversity.

Seeking the Psilocybiome: Psychedelics meet the microbiota-gut-brain axis

Moving towards a systems psychiatry paradigm embraces the inherent complex interactions across all levels from micro to macro and necessitates an integrated approach to treatment. Cortical 5-HT2A receptors are key primary targets for the effects of serotonergic psychedelics. However, the therapeutic mechanisms underlying psychedelic therapy are complex and traverse molecular, cellular, and network levels, under the influence of biofeedback signals from the periphery and the environment. At the interface between the individual and the environment, the gut microbiome, via the gut-brain axis, plays an important role in the unconscious parallel processing systems regulating host neurophysiology. While psychedelic and microbial signalling systems operate over different timescales, the microbiota-gut-brain (MGB) axis, as a convergence hub between multiple biofeedback systems may play a role in the preparatory phase, the acute administration phase, and the integration phase of psychedelic therapy. In keeping with an interconnected systems-based approach, this review will discuss the gut microbiome and mycobiome and pathways of the MGB axis, and then explore the potential interaction between psychedelic therapy and the MGB axis and how this might influence mechanism of action and treatment response. Finally, we will discuss the possible implications for a precision medicine-based psychedelic therapy paradigm.

The Microbiome-Gut-Brain axis regulates social cognition & craving in young binge drinkers

BACKGROUND

Binge drinking is the consumption of an excessive amount of alcohol in a short period of time. This pattern of consumption is highly prevalent during the crucial developmental period of adolescence. Recently, the severity of alcohol use disorders (AUDs) has been linked with microbiome alterations suggesting a role for the gut microbiome in its development. Furthermore, a strong link has emerged too between microbiome composition and socio-emotional functioning across different disorders including AUD. The aim of this study was to investigate the potential link (and its predictive value) between alcohol-related altered microbial profile, social cognition, impulsivity and craving.

METHODS

Young people (N = 71) aged 18-25 reported their alcohol use and underwent a neuropsychological evaluation. Craving was measured at baseline and three months later. Diet was controlled for. Blood, saliva and hair samples were taken for inflammatory, kynurenine and cortisol analysis. Stool samples were provided for shotgun metagenomic sequencing and short-chain fatty acids (SCFAs) were measured.

FINDINGS

Binge drinking was associated with distinct microbiome alterations and emotional recognition difficulties. Associations were found for several microbiome species with emotional processing and impulsivity. Craving showed a strong link with alterations in microbiome composition and neuroactive potential over time.

INTERPRETATION

In conclusion, this research demonstrates alterations in the gut microbiome of young binge drinkers (BDs) and identifies early biomarkers of craving. Associations between emotional processing and microbiome composition further support the growing literature on the gut microbiome as a regulator of social cognition. These findings are of relevance for new gut-derived interventions directed at improving early alcohol-related alterations during the vulnerability period of adolescence.

FUNDING

C.C. and R.G-C. received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 754535. APC Microbiome Ireland is a research centre funded by Science Foundation Ireland (SFI), through the Irish Government's National Development Plan [grant no. SFI/12/RC/2273_P2]. J.F.C has research support from Cremo, Pharmavite, DuPont and Nutricia. He has spoken at meetings sponsored by food and pharmaceutical companies. G.C. has received honoraria from Janssen, Probi, and Apsen as an invited speaker; is in receipt of research funding from Pharmavite, Fonterra, Nestle and Reckitt; and is a paid consultant for Yakult, Zentiva and Heel pharmaceuticals. All the authors declare no competing interests.

The different trends in the burden of neurological and mental disorders following dietary transition in China, the USA, and the world: An extension analysis for the Global Burden of Disease Study 2019

Introduction

The highly processed western diet is substituting the low-processed traditional diet in the last decades globally. Increasing research found that a diet with poor quality such as western diet disrupts gut microbiota and increases the susceptibility to various neurological and mental disorders, while a balanced diet regulates gut microbiota and prevents and alleviates the neurological and mental disorders. Yet, there is limited research on the association between the disease burden expanding of neurological and mental disorders with a dietary transition.

Methods

We compared the disability-adjusted life-years (DALYs) trend by age for neurological and mental disorders in China, in the United States of America (USA), and across the world from 1990 to 2019, evaluated the dietary transition in the past 60 years, and analyzed the association between the burden trend of the two disorders with the changes in diet composition and food production.

Results

We identified an age-related upward pattern in disease burden in China. Compared with the USA and the world, the Chinese neurological and mental disorders DALY percent was least in the generation over 75 but rapidly increased in younger generations and surpassed the USA and/or the world in the last decades. The age-related upward pattern in Chinese disease burdens had not only shown in the presence of cardiovascular diseases, neoplasms, and diabetes mellitus but also appeared in the presence of depressive disorders, Parkinson's disease, Alzheimer's disease and other dementias, schizophrenia, headache disorders, anxiety disorders, conduct disorders, autism spectrum disorders, and eating disorders, successively. Additionally, the upward trend was associated with the dramatic dietary transition including a reduction in dietary quality and food production sustainability, during which the younger generation is more affected than the older. Following the increase in total calorie intake, alcohol intake, ratios of animal to vegetal foods, and poultry meat to pulses, the burdens of the above diseases continuously rose. Then, following the rise of the ratios of meat to pulses, eggs to pulses, and pork to pulses, the usage of fertilizers, the farming density of pigs, and the burdens of the above disease except diabetes mellitus were also ever-increasing. Even the usage of pesticides was positively correlated with the burdens of Parkinson's disease, schizophrenia, cardiovascular diseases, and neoplasms. Contrary to China, the corresponding burdens of the USA trended to reduce with the improvements in diet quality and food production sustainability.

Discussion

Our results suggest that improving diet quality and food production sustainability might be a promising way to stop the expanding burdens of neurological and mental disorders.

The gut microbiota alone and in combination with a social stimulus regulates cocaine reward in the mouse

The gut microbiota is a key factor in the maintenance of physiological homeostasis and immunity. Correlational studies have demonstrated that alterations in microbiota composition have been associated with addiction. Moreover, animal studies have confirmed a link between reward and social processes, which may be shaped by the gut microbiota thus influencing neurodevelopment and the programming of social behaviors across diverse animal species. However, whether there is an interaction between the microbiota and social reward processes in the context of drug reward remains unclear. To this end, we explored the influence of gut microbiota in regulating behaviourally conditioned responses to different rewards (cocaine and social interactions). Depletion of the intestinal microbiota resulted in differential reward responses to both drug and social stimuli with an attenuation of the former and enhancement of the latter independent of concomitant immune changes. Moreover, the combination of depleting the gut microbiota in the presence of a positive social stimulus attenuates cocaine reward. Together these data suggest that the two-pronged approach of targeting the microbiota and enhancing social behaviour could constitute a valuable component in reducing harm in drug use by altering the salient effects of cocaine.

Differentiation between alcohol-associated cirrhosis and hepatitis B-associated cirrhosis based on hepatic complications and psychological symptoms

Background

The prognosis of and occurrence of complications in patients with different clinical features of cirrhosis differ, and cirrhosis with different etiologies has varying clinical characteristics. The aim of this study was to describe the liver function markers, hepatic complications, and psychological features differentiating patients with hepatitis B virus (HBV) infection-related and alcohol-related cirrhosis.

Materials and Methods

This was a retrospective and observational study that analyzed the medical data of inpatients with alcohol-related or HBV infection-related cirrhosis from May 2014 to May 2020. Markers of liver function, portal hypertension, and psychological symptoms were compared between the two groups.

Results

Patients with alcohol-related cirrhosis showed higher Self-Rating Anxiety Scale scores and prevalence of hypoproteinemia, fatty liver, and depression than those with HBV infection-related cirrhosis (all P < 0.05). After adjustment for potential confounders, patients with alcohol-related cirrhosis also showed higher risks of increased total cholesterol (odds ratio [OR] =2.671, 95% confidence interval [CI]: 1.160-6.151, P = 0.021), increased high-density lipoprotein-cholesterol (OR = 2.714, 95% CI: 1.009-7.299, P = 0.048), and fatty liver (OR = 2.713, 95% CI: 1.002-7.215, P = 0.048); however, splenomegaly and splenectomy were significantly associated with HBV infection-related cirrhosis (OR = 2.320, 95% CI: 1.066-5.050, P = 0.034).

Conclusion

Patients with alcohol-related cirrhosis were more likely to develop hyperlipidemia, fatty liver, and psychological symptoms, whereas those with HBV-related cirrhosis had a higher risk of splenomegaly.

The Role of the Adenosine System on Emotional and Cognitive Disturbances Induced by Ethanol Binge Drinking in the Immature Brain and the Beneficial Effects of Caffeine

Binge drinking intake is the most common pattern of ethanol consumption by adolescents, which elicits emotional disturbances, mainly anxiety and depressive symptoms, as well as cognitive alterations. Ethanol exposure may act on the adenosine neuromodulation system by increasing adenosine levels, consequently increasing the activation of adenosine receptors in the brain. The adenosine modulation system is involved in the control of mood and memory behavior. However, there is a gap in the knowledge about the exact mechanisms related to ethanol exposure’s hazardous effects on the immature brain (i.e., during adolescence) and the role of the adenosine system thereupon. The present review attempts to provide a comprehensive picture of the role of the adenosinergic system on emotional and cognitive disturbances induced by ethanol during adolescence, exploring the potential benefits of caffeine administration in view of its action as a non-selective antagonist of adenosine receptors.

Alterations in gut microbiota affect behavioral and inflammatory responses to methamphetamine in mice

RATIONALE AND OBJECTIVES

Methamphetamine (METH) is a highly addictive and widely abused drug that causes severe neuroinflammation in the human brain. The gut microbiota has a tremendous impact on the core symptoms of neuropsychiatric disorders via the microbiota-gut-brain (MGB) axis. However, it is not clear whether alterations in the gut microbiota are involved in METH exposure.

METHODS

We established a mouse model with chronic, escalating doses of METH exposure. Intervene in gut microbiota with antibiotics to observe the changes of locomotor activity caused by METH exposure in mice. qPCR and 16S rRNA gene sequencing were used to analyze the gut microbiota profiles. In addition, we tested the levels of inflammatory factors in the nucleus accumbens (NAc), prefrontal cortex (mPFC), hippocampus (HIp), and spleen. Finally, short-chain fatty acids (SCFAs) were supplemented to determine the interaction between behavior changes and the structure of gut microbiota.

RESULTS

In this research, METH increased the locomotor activity of mice, while antibiotics changed the effect. Antibiotics enhanced the expression of pro-inflammatory cytokines in mPFC, HIp, and spleen of METH-exposed mice. METH altered the gut microbiota of mice after antibiotic treatment, such as Butyricicoccus and Roseburia, which are related to butyrate metabolism. Supplementation with SCFAs changed the behavior of METH-exposed mice and decreased Parabacteroides and increased Lactobacillus in METH-exposed mice gut.

CONCLUSIONS

This research showed that antibiotics affected the behavior of METH-exposed mice and promoted inflammation. Our findings suggest that SCFAs might regulate METH-induced gut microbiota changes and behavior.

The gut microbiome and mental health: advances in research and emerging priorities

The gut microbiome exerts a considerable influence on human neurophysiology and mental health. Interactions between intestinal microbiology and host regulatory systems have now been implicated both in the development of psychiatric conditions and in the efficacy of many common therapies. With the growing acceptance of the role played by the gut microbiome in mental health outcomes, the focus of research is now beginning to shift from identifying relationships between intestinal microbiology and pathophysiology, and towards using this newfound insight to improve clinical outcomes. Here, we review recent advances in our understanding of gut microbiome-brain interactions, the mechanistic underpinnings of these relationships, and the ongoing challenge of distinguishing association and causation. We set out an overarching model of the evolution of microbiome-CNS interaction and examine how a growing knowledge of these complex systems can be used to determine disease susceptibility and reduce risk in a targeted manner.

Psychoactive Effects of Lactobacillus johnsonii BS15 on Preventing Memory Dysfunction Induced by Acute Ethanol Exposure Through Modulating Intestinal Microenvironment and Improving Alcohol Metabolic Level

The negative effects of ethanol (EtOH) abuse on the body have been widely reported in recent years. Building on the microbiota-gut-brain axis hypothesis, our study aimed to demonstrate the potential psychobiotic role of Lactobacillus johnsonii BS15 in the preventive effects of acute EtOH intake on memory impairment. We also determined whether L. johnsonii BS15 intake could effectively improve resistance to acute drinking and alleviate the adverse effects of EtOH. Male mice were fed L. johnsonii BS15 orally with (Probiotic group) or without (Control and Alcohol groups) daily dose of 0.2 × 109 CFU/ml per mouse for 28 days. Gavage with L. johnsonii BS15 significantly modified the ileal microbial ecosystem (assessed by 16S rRNA gene sequencing) in favor of Firmicutes and Lactobacillus, indicating the ability of BS15 to restore the gut microbiota. The acute EtOH exposure model (7 g/kg EtOH per mice) was established by gavage, which was administered to the alcohol and probiotic groups on day 28 of the experiment. The L. johnsonii BS15 intake effectively reduced alcohol unconsciousness time, blood alcohol concentration, and serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. Meanwhile, the improvement of ethanol resistance time and the activities of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) in the liver were shown by BS15 in acute alcohol-induced mice. We found that acute EtOH exposure reduced the exploration ratio (assessed by the novel object recognition test), escape latency, number of errors (assessed by passive avoidance test), and spontaneous exploration (assessed by T-maze test) in mice, which were obviously improved by L. johnsonii BS15. In the hippocampus, L. johnsonii BS15 significantly reversed the decrease in antioxidant capacity of superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) and mRNA expression of memory-related functional proteins of brain-derived neurotrophic factor (BDNF) and cyclic ampresponse element binding protein (CREB) in the hippocampal tissue after acute EtOH exposure. In conclusion, L. johnsonii BS15 intake appears as a promising psychoactive therapy to ameliorate alcohol-mediated memory impairment by increasing EtOH metabolic levels.

The diversity of the intestinal microbiota in patients with alcohol use disorder and its relationship to alcohol consumption and cognition

INTRODUCTION

Alcohol use disorder (AUD) has evolved into a severe social and medical issue. However, the exact environmental factors triggering AUD pathophysiology remain unknown. A growing body of research has shown that environmental elements can affect the brain via the microbiota-gut-brain axis.

METHODS

We employed 16S rRNA gene sequencing technology to investigate the composition and diversity of intestinal microbiota in 32 AUD males and 35 healthy controls (HCs), as well as its relationship on cognitive function.

RESULTS

Our findings showed that the alpha diversity indices in AUDs were much lower than HCs. The abundances of Faecalibacterium, Gemmiger, Lachnospiracea_incertae_sedis, Megamonas, and Escherichia were significantly different between AUD and HC groups and could be used as a basis for judging whether excessive drinking. The abundances of Faecalibacterium, Gemmiger, Escherichia, and Fusobacterium can be used to judge the cognitive function of the population.

CONCLUSION

These data suggested that the gut dysbiosis in AUD patients, and some specific microbiota were considered to be related to alcohol intake and cognitive function. This study provides important information for further study of the pathogenesis of AUD from the perspective of intestinal microbiota.

Exploring the role of immune pathways in the risk and development of depression in adolescence: Research protocol of the IDEA-FLAME study

Extensive research suggests a role for the innate immune system in the pathogenesis of depression, but most of the studies are conducted in adult populations, in high-income countries and mainly focus on the study of inflammatory proteins alone, which provides only a limited understanding of the immune pathways involved in the development of depression. The IDEA-FLAME study aims to identify immune phenotypes underlying increased risk of developing depression in adolescence in a middle-income country. To this end, we will perform deep-immunophenotyping of peripheral blood mononuclear cells and RNA genome-wide gene expression analyses in a longitudinal cohort of Brazilian adolescents stratified for depression risk. The project will involve the 3-year follow-up of an already recruited cohort of 150 Brazilian adolescents selected for risk/presence of depression on the basis of a composite risk score we developed using sociodemographic characteristics (50 adolescents with low-risk and 50 with high-risk of developing depression, and 50 adolescents with a current major depressive disorder). We will 1) test whether the risk group classification at baseline is associated with differences in immune cell frequency, phenotype and functional status, 2) test whether baseline immune markers (cytokines and immune cell markers) are associated with severity of depression at 3-year follow-up, and 3) identify changes in gene expression of immune pathways over the 3-year follow-up in adolescents with increased risk and presence of depression. Because of the exploratory nature of the study, the findings would need to be replicated in a separate and larger sample. Ultimately, this research will contribute to elucidating key immune therapeutic targets and inform the development of interventions to prevent onset of depression among adolescents.

Single Cell Scale Neuronal and Glial Gene Expression and Putative Cell Phenotypes and Networks in the Nucleus Tractus Solitarius in an Alcohol Withdrawal Time Series

Alcohol withdrawal syndrome (AWS) is characterized by neuronal hyperexcitability, autonomic dysregulation, and severe negative emotion. The nucleus tractus solitarius (NTS) likely plays a prominent role in the neurological processes underlying these symptoms as it is the main viscerosensory nucleus in the brain. The NTS receives visceral interoceptive inputs, influences autonomic outputs, and has strong connections to the limbic system and hypothalamic-pituitary-adrenal axis to maintain homeostasis. Our prior analysis of single neuronal gene expression data from the NTS shows that neurons exist in heterogeneous transcriptional states that form distinct functional subphenotypes. Our working model conjectures that the allostasis secondary to alcohol dependence causes peripheral and central biological network decompensation in acute abstinence resulting in neurovisceral feedback to the NTS that substantially contributes to the observed AWS. We collected single noradrenergic and glucagon-like peptide-1 (GLP-1) neurons and microglia from rat NTS and measured a subset of their transcriptome as pooled samples in an alcohol withdrawal time series. Inflammatory subphenotypes predominate at certain time points, and GLP-1 subphenotypes demonstrated hyperexcitability post-withdrawal. We hypothesize such inflammatory and anxiogenic signaling contributes to alcohol dependence via negative reinforcement. Targets to mitigate such dysregulation and treat dependence can be identified from this dataset.

Sodium Butyrate Protects Against Ethanol-Induced Toxicity in SH-SY5Y Cell Line

Alcohol use disorder (AUD), brought about by excessive alcohol use, is associated with damages to several organs including the brain. Chronic excessive use of alcohol can compromise intestinal integrity, leading to changes in gut microbiota (GM) composition known as dysbiosis. Dysbiosis, by disruption of the gut-brain axis (GBA), further exacerbates the deleterious effects of alcohol. One of the fermentation by-products of GM is butyrate (BUT), a short-chain fatty acid (SCFA) that plays an important role in maintaining homeostasis of the GBA. Alcohol metabolism results in formation of acetaldehyde, a highly reactive compound that reacts with dopamine in the brain to form toxic adducts such as salsolinol. Recent studies indicate potential neuro-protective effects of BUT against various toxicants including salsolinol. Here, we sought to investigate whether BUT can also protect against alcohol toxicity. Pretreatment of neuroblastoma-derived SH-SY5Y cells with 500 mM ethanol (ETOH) for 24 h resulted in approximately 40% reduction in cell viability, which was totally blocked by 10 µM of either BUT or AR 420,626 (AR), a selective fatty acid 3 receptor (FA3R) agonist. The neuro-protective effects of both BUT and AR were significantly (80%) attenuated by beta-hydroxy butyrate (BHB), a selective FA3R antagonist. Interestingly, combination of BUT and AR resulted in synergistic protection against ETOH, which was totally blocked by BHB. These findings suggest potential utility of butyrate and/or FA3R agonists against ETOH-induced toxicity.

Age and Living Situation as Key Factors in Understanding Changes in Alcohol Use during COVID-19 Confinement

(1) The aim of the present study was to evaluate and characterize changes in alcohol use during the COVID-19 confinement in a sample of Spanish adults, analyzing their age and living situation as defining life cycle variables. (2) Method: Data from 3779 individuals were collected through a set of online surveys. AUDIT-C was used to measure the frequency of consumption, the average daily consumption, intensive consumption, risky consumption, and Standard Drink Units. (3) Results: Although alcohol consumption during confinement showed a significant general decline, age revealed important differences, with the decline being more pronounced in adults from 18 to 29 years old. The living situation also showed significant differences. The largest decreases in alcohol consumption were found in those who lived with their parents or other relatives, whereas those who lived alone or with a partner even increased their level of consumption. In addition, the data show a significant interaction between these two variables and gender. (4) Conclusions: Age and cohabitation processes are key factors in understanding the life situation of each individual during confinement and, consequently, in explaining consumption patterns. The results obtained provide interesting recommendations for designing prevention policies in both normal and crisis circumstances, emphasizing the need to understand alcohol use from a psychosocial perspective.

Microbiome First Approaches to Rescue Public Health and Reduce Human Suffering

The is a sequential article to an initial review suggesting that Microbiome First medical approaches to human health and wellness could both aid the fight against noncommunicable diseases and conditions (NCDs) and help to usher in sustainable healthcare. This current review article specifically focuses on public health programs and initiatives and what has been termed by medical journals as a catastrophic record of recent failures. Included in the review is a discussion of the four priority behavioral modifications (food choices, cessation of two drugs of abuse, and exercise) advocated by the World Health Organization as the way to stop the ongoing NCD epidemic. The lack of public health focus on the majority of cells and genes in the human superorganism, the microbiome, is highlighted as is the "regulatory gap" failure to protect humans, particularly the young, from a series of mass population toxic exposures (e.g., asbestos, trichloroethylene, dioxin, polychlorinated biphenyls, triclosan, bisphenol A and other plasticizers, polyfluorinated compounds, herbicides, food emulsifiers, high fructose corn syrup, certain nanoparticles, endocrine disruptors, and obesogens). The combination of early life toxicity for the microbiome and connected human physiological systems (e.g., immune, neurological), plus a lack of attention to the importance of microbial rebiosis has facilitated rather than suppressed, the NCD epidemic. This review article concludes with a call to place the microbiome first and foremost in public health initiatives as a way to both rescue public health effectiveness and reduce the human suffering connected to comorbid NCDs.

The Microbiome-Gut-Brain Axis, a Potential Therapeutic Target for Substance-Related Disorders

Substance addiction is a complex worldwide public health problem. It endangers both personal life and social stability, causing great loss on economy. Substance-related disorder is considered to be a complicated chronic brain disorder. It resulted from interactions among pharmacological properties of addictive substances, individual susceptibility, and social–environmental factors. Unfortunately, there is still no ideal treatment for this disorder. Recent lines of evidence suggest that gut microbiome may play an important role in the pathogenesis of neuropsychiatric disorders, including substance-related disorders. This review summarizes the research on the relationship between gut microbiome and substance-related disorders, including different types of substance, different individual susceptibility, and the occurrence and development of substance-induced mental disorders. We also discuss the potentiation of gut microbiome in the treatment of substance-related disorders, especially in the treatment of substance-induced mental disorders and manipulation on individuals’ responsiveness to addictive substances.

Associations between Mental Health, Alcohol Consumption and Drinking Motives during COVID-19 Second Lockdown in Ireland

Aims

The novel coronavirus pandemic (COVID-19) has impacted the lives of people worldwide since March 2020. Social restrictions aimed at flattening the curve may be associated with an increase in mental health problems and have raised concerns regarding their effect on alcohol consumption. The objective of this study was to characterize changes in alcohol use during lockdown in Ireland and associations with drinking motives and psychopathological symptoms.

Methods

We collected data from 713 adults (aged 18–60) during the second lockdown period (October/December 2020). By means of an online survey, participants self-reported their alcohol use before COVID and during lockdown. Motives to drink and psychopathological symptoms were also recorded.

Results

Our findings showed that 66% decreased their alcohol consumption, while 15% increased their alcohol consumption. An older age and coping motives were the strongest predictors of increased alcohol use during lockdown. Depression and hostility were the specific psychopathological dimensions associated with drinking to cope.

Conclusions

Older adults who drink to cope—mainly with depression symptomatology—are an important at-risk population, in line with predictions from alcohol self-medication frameworks. Future research is needed to incorporate strategies into the public mental health ecosystem.

Does alcohol affect emotional face processing via interoceptive pathways?

BACKGROUND

Our brain uses interoceptive signals from the body to shape how we perceive emotions in others; however, whether interoceptive signals can be manipulated to alter emotional perceptions is unknown. Alcohol has acute effects both on emotional processing and on the physiological substrates supporting interoception. In this registered report, we examine whether alcohol administration triggers physiological changes that alter interoceptive signals and manipulate emotional face processing. Such knowledge will broaden understanding of the mechanisms by which alcohol affects emotional face processing.

METHODS

Participants (n = 36) will be administered an alcohol or placebo beverage. Cardiovascular physiology will be recorded before and after administration. Participants will complete two behavioral tasks in which they view emotional faces presented in synchrony with different phases of the cardiac cycle (i.e., systole, diastole). This manipulation creates an index of how interoceptive signals amplify emotional face processing.

HYPOTHESES

We hypothesize that, compared to placebo, alcohol administration will disrupt the cardiac amplification of emotional face processing. We further explore whether this disruption depends on the nature and magnitude of changes in cardiovascular physiology after alcohol administration.

Drugs and bugs: Negative affect, psychostimulant use and withdrawal, and the microbiome

BACKGROUND AND OBJECTIVES

A growing body of literature demonstrates that the human microbiota plays a crucial role in health and disease states, as well as in the body's response to stress. In addition, the microbiome plays a role in psychological well-being and regulating negative affect. Regulation of negative affect is a factor in psychostimulant abuse disorders. We propose a risk chain in which stress leads to negative affect that places an individual at risk to develop or relapse to psychostimulant abuse disorder. Stress, negative affect, and psychostimulant use all alter the gut microbiome.

METHODS

This review brings together the literature on affective disorders, stress, and psychostimulant abuse disorders to assess possible modulatory actions of the gut-brain axis to regulate these conditions.

RESULTS

Studies reviewed across the various disciplines suggest that the dysbiosis resulting from drug use, drug withdrawal, or stress may cause an individual to be more susceptible to addiction and relapse. Probiotics and prebiotics reduce stress and negative affect.

SCIENTIFIC SIGNIFICANCE

Treatment during the withdrawal phase of psychostimulant abuse disorder, when the microbiome is altered, may ameliorate the symptoms of stress and negative affect leading to a reduced risk of relapse to psychostimulant use.

Microbiota-gut-brain axis as a regulator of reward processes

Our gut harbours trillions of microorganisms essential for the maintenance of homeostasis and host physiology in health and disease. In the last decade, there has been a growing interest in understanding the bidirectional pathway of communication between our microbiota and the central nervous system. With regard to reward processes there is accumulating evidence from both animal and human studies that this axis may be a key factor in gating reward valence. Focusing on the mesocorticolimbic pathway, we will discuss how the intestinal microbiota is involved in regulating brain reward functions, both in natural (i.e. eating, social or sexual behaviours) and non-natural reinforcers (drug addiction behaviours including those relevant to alcohol, psychostimulants, opioids and cannabinoids). We will integrate preclinical and clinical evidence suggesting that the microbiota-gut-brain axis could be implicated in the development of disorders associated with alterations in the reward system and how it may be targeted as a promising therapeutic strategy. Cover Image for this issue: https://doi.org/10.1111/jnc.15065.