Intestinal permeability, gut-bacterial dysbiosis, and behavioral markers of alcohol-dependence severity

Association between chronic psychoactive substances use and systemic inflammation: A systematic review and meta-analysis

This systematic review and meta-analysis assess the change in inflammation biomarkers level among chronic psychoactive substance users. To meet the required inclusion criteria, all studies had to describe human participants with an age ≥18y., experiencing chronic psychostimulant (nicotine, amphetamine, cocaine), sedative (benzodiazepine, opioids) and/or cannabinoid use. The comparison group was defined as healthy participants. Studies where included if they reported at least one of the pro/inflammatory biomarkers. Study bias was examined by Funnel plots and heterogeneity by computing the I² statistics. Only 21 eligible studies were selected based on 26,216 study participants. A small and significant effect size of 0.18 mg/l (95 % CI:0.10-0.27) was detected in favour of chronic smokers (z = 4.33;P < 0.0001). There was evidence of publication bias for studies measuring IL-6 and IL-10 association with cocaine and IL-6 in association with cannabis. In summary, except for chronic tobacco users, there was no evidence of association between other chronic substances abuse and inflammatory levels. More studies are needed to inform policy and decision makers about the utility of anti-inflammatory based targeted intervention programmes.

New Insights Into the Cancer-Microbiome-Immune Axis: Decrypting a Decade of Discoveries

The past decade has witnessed groundbreaking advances in the field of microbiome research. An area where immense implications of the microbiome have been demonstrated is tumor biology. The microbiome affects tumor initiation and progression through direct effects on the tumor cells and indirectly through manipulation of the immune system. It can also determine response to cancer therapies and predict disease progression and survival. Modulation of the microbiome can be harnessed to potentiate the efficacy of immunotherapies and decrease their toxicity. In this review, we comprehensively dissect recent evidence regarding the interaction of the microbiome and anti-tumor immune machinery and outline the critical questions which need to be addressed as we further explore this dynamic colloquy.

Supplemental Xylooligosaccharide Modulates Intestinal Mucosal Barrier and Cecal Microbiota in Laying Hens Fed Oxidized Fish Oil

Our previous study indicated that dietary xylooligosaccharide (XOS) supplementation improved feed efficiency, ileal morphology, and nutrient digestibility in laying hens. The objective of this study was to evaluate the mitigative effects of XOS on intestinal mucosal barrier impairment and microbiota dysbiosis induced by oxidized fish oil (OFO) in laying hens. A total of 384 Hy-Line Brown layers at 50 weeks of age were randomly divided into four dietary treatments, including the diets supplemented with 20 g/kg of fresh fish oil (FFO group) or 20 g/kg of oxidized fish oil (OFO group), and the OFO diets with XOS addition at 200 mg/kg (OFO/XOS200 group) or 400 mg/kg (OFO/XOS400 group). Each treatment had eight replicates with 12 birds each. The OFO treatment decreased (P < 0.05) the production performance of birds from 7 to 12 weeks of the experiment, reduced (P < 0.05) ileal mucosal secretory immunoglobulin A (sIgA) content, and increased (P < 0.05) serum endotoxin concentration, as well as downregulated (P < 0.05) mRNA expression of claudin-1 (CLDN1) and claudin-5 (CLDN5) in the ileal mucosa at the end of the experiment. Dietary XOS addition (400 mg/kg) recovered (P < 0.05) these changes and further improved (P < 0.05) ileal villus height (VH) and the villus height-to-crypt depth ratio (VCR). In addition, OFO treatment altered cecal microbial composition of layers, and these alterations were probably involved in OFO-induced ileal mucosal impairment as causes or consequences. Supplemental XOS remodeled cecal microbiota of layers fed the OFO diet, characterized by an elevation in microbial richness and changes in microbial composition, including increases in Firmicutes, Ruminococcaceae, Verrucomicrobia (Akkermansia), Paraprevotella, Prevotella_9, and Oscillospira, along with a decrease in Erysipelatoclostridium. The increased abundance of Verrucomicrobia (Akkermansia) had positive correlations with the improved ileal VH and ileal mucosal expression of CLDN1. The abundance of Erysipelatoclostridium decreased by XOS addition was negatively associated with ileal VH, VCR, ileal mucosal sIgA content, and the relative expression of zonula occludens-2, CLDN1, and CLDN5. Collectively, supplemental XOS alleviated OFO-induced intestinal mucosal barrier dysfunction and performance impairment in laying hens, which could be at least partially attributed to the modulation of gut microbiota.

Regulation of Intestinal Barrier Function by Microbial Metabolites

The human gastrointestinal tract (GI) harbors a diverse population of microbial life that continually shapes host pathophysiological responses. Despite readily available abundant metagenomic data, the functional dynamics of gut microbiota remain to be explored in various health and disease conditions. Microbiota generate a variety of metabolites from dietary products that influence host health and pathophysiological functions. Since gut microbial metabolites are produced in close proximity to gut epithelium, presumably they have significant impact on gut barrier function and immune responses. The goal of this review is to discuss recent advances on gut microbial metabolites in the regulation of intestinal barrier function. While the mechanisms of action of these metabolites are only beginning to emerge, they mainly point to a small group of shared pathways that control gut barrier functions. Amidst expanding technology and broadening knowledge, exploitation of beneficial microbiota and their metabolites to restore pathophysiological balance will likely prove to be an extremely useful remedial tool.

The Association between Early-Life Gut Microbiota and Long-Term Health and Diseases

Early life gut microbiota have been increasingly recognized as major contributors to short and/or long-term human health and diseases. Numerous studies have demonstrated that human gut microbial colonization begins at birth, but continues to develop a succession of taxonomic abundances for two to three years until the gut microbiota reaches adult-like diversity and proportions. Several factors, including gestational age (GA), delivery mode, birth weight, feeding types, antibiotic exposure, maternal microbiome, and diet, influence the diversity, abundance, and function of early life gut microbiota. Gut microbial life is essential for assisting with the digestion of food substances to release nutrients, exerting control over pathogens, stimulating or modulating the immune system, and influencing many systems such as the liver, brain, and endocrine system. Microbial metabolites play multiple roles in these interactions. Furthermore, studies provide evidence supporting that imbalances of the gut microbiota in early life, referred to as dysbiosis, are associated with specific childhood or adult disease outcomes, such as asthma, atopic dermatitis, diabetes, allergic diseases, obesity, cardiovascular diseases (CVD), and neurological disorders. These findings support that the human gut microbiota may play a fundamental role in the risk of acquiring diseases that may be programmed during early life. In fact, it is critical to explore the role of the human gut microbiota in early life.

Clinical Neuroscience of Addiction: What Clinical Psychologists Need to Know and Why

The last three decades in psychological research have been marked by interdisciplinary science. Addiction represents a prime example of a disorder marked by a complex interaction among psychosocial and biological factors. This review highlights critical findings in the basic neuroscience of addiction and translates them into clinical language that can inform clinical psychologists in their research, teaching, and practice. From mechanisms of reward processing, learning and memory, allostasis, incentive-sensitization, withdrawal, tolerance, goal-directed decision making, habit learning, genetics, inflammation, and the microbiome, the common theme of this review is to illustrate the clinical utility of basic neuroscience research and to identify opportunities for clinical science. The thoughtful integration of basic and clinical science provides a powerful tool to fulfill the scientific mission of improving health care. Clinical psychologists have a crucial role to play in the translational science of addiction.

Not All Fibers Are Born Equal; Variable Response to Dietary Fiber Subtypes in IBD

Diet provides a safe and attractive alternative to available treatment options in a variety of diseases; however, research has only just begun to elucidate the role of diet in chronic diseases, such as the inflammatory bowel diseases (IBD). The chronic and highly debilitating IBDs, Crohn disease and ulcerative colitis, are hallmarked by intestinal inflammation, immune dysregulation, and dysbiosis; and evidence supports a role for genetics, microbiota, and the environment, including diet, in disease pathogenesis. This is true especially in children with IBD, where diet-based treatments have shown excellent results. One interesting group of dietary factors that readily links microbiota to gut health is dietary fibers. Fibers are not digested by human cells, but rather fermented by the gut microbes within the bowel. Evidence has been mounting over the last decade in support of the importance of dietary fibers in the maintenance of gut health and in IBD; however, more recent studies highlight the complexity of this interaction and importance of understanding the role of each individual dietary fiber subtype, especially during disease. There are roughly ten subtypes of dietary fibers described to date, categorized as soluble or insoluble, with varying chemical structures, and large differences in their fermentation profiles. Many studies to date have described the benefits of the byproducts of fermentation in healthy individuals and the potential health benefits in select disease models. However, there remains a void in our understanding of how each of these individual fibers affect human health in dysbiotic settings where appropriate fermentation may not be achieved. This review highlights the possibilities for better defining the role of individual dietary fibers for use in regulating inflammation in IBD.

A sensitive electrochemical method for indole based on the signal amplification strategy by gold/iron-oxide composite nanoparticles

Indole is a major metabolite of tryptophan, which plays an important role in the intestinal microecological balance and human physiological activities. The determination of indole becomes important for its researches. So, it is urgent to establish a sensitive and cost-effective method for indole detection. Herein, a sensitive electrochemical method was constructed to determine the concentration of indole using screen-printed carbon electrode (SPCE) with the signal amplification strategy by gold/iron-oxide composite nanoparticles (Au/Fe₃O₄). Au/Fe₃O₄ nanoparticles were successfully synthesized under the irradiation by high-energy electron beams. 4-aminothiophenol (4-ATP) was connected to Au/Fe₃O₄ via Au-S bond. And then NaNO₂ reacted with 4-ATP to form the azo bond, which could form the final product of Au/Fe₃O₄@ATP-azo-indole by the coupling reaction. Thus, the concentration of indole was detected by the electrochemical signal produced by Au/Fe₃O₄@ATP-azo-indole indirectly. The detection sensitivity was greatly improved by the large specific surface area provided by Au/Fe₃O₄ after the modification. The linear range of indole was from 0.50 to 120.00 μg L^-1 and the limit of detection (LOD) was as low as 0.10 μg L^-1 (S/N = 3). Furthermore, the developed method exhibited acceptable intra-day and inter-day precisions with the coefficient of variations (CV) less than 4.9% and 8.2%, respectively. And the recoveries were from 97.2% to 105.4%. An innovative, sensitive, cost-effective method was established for indole determination in human plasma matrix in this manuscript, which provides a promising way for indole detection in conventional laboratories.

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.

Gut microbiome changes in Nonalcoholic fatty liver disease & alcoholic liver disease

Nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are some of the most common liver diseases worldwide. The human gut microbiome is dynamic and shifts in bacterial composition have been implicated in many diseases. Studies have shown that there is a shift in bacterial overgrowth favoring pro-inflammatory mediators in patients with advanced disease progression such as cirrhosis. Further investigation demonstrated that the transplantation of gut microbiota from advanced liver disease patients can reproduce severe liver inflammation and injury in mice. Various techniques in manipulating the gut microbiota have been attempted including fecal transplantation and probiotics. This review focuses on the changes in the gut microbiota as well as emerging lines of microbiome work with respect to NAFLD and ALD.

New Developments in Microbiome in Alcohol-Associated and Nonalcoholic Fatty Liver Disease

Alcohol-associated liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are important causes of morbidity and mortality worldwide. The intestinal microbiota is involved in the development and progression of both ALD and NAFLD. Here we describe associated changes in the intestinal microbiota, and we detail randomized clinical trials in ALD and NAFLD which evaluate treatments modulating the intestinal microbiome including fecal microbiota transplantation, probiotics, prebiotics, synbiotics, and antibiotics. Finally, we discuss precision medicine approaches targeting the intestinal microbiome to ameliorate ALD and NAFLD.

Chronic Liver Diseases and the Microbiome-Translating Our Knowledge of Gut Microbiota to Management of Chronic Liver Disease

Chronic liver disease is reaching epidemic proportions with the increasing prevalence of obesity, nonalcoholic liver disease, and alcohol overuse worldwide. Most patients are not candidates for liver transplantation even if they have end-stage liver disease. There is growing evidence of a gut microbial basis for many liver diseases, therefore, better diagnostic, prognostic, and therapeutic approaches based on knowledge of gut microbiota are needed. We review the questions that need to be answered to successfully translate our knowledge of the intestinal microbiome and the changes associated with liver disease into practice.

From "Leaky Gut" to Impaired Glia-Neuron Communication in Depression

In the last three decades, the robust scientific data emerged, demonstrating that the immune-inflammatory response is a fundamental component of the pathophysiology of major depressive disorder (MDD). Psychological stress and various inflammatory comorbidities contribute to such immune activation. Still, this is not uncommon that patients with depression do not have defined inflammatory comorbidities, and alternative mechanisms of immune activation need to take place. The gastrointestinal (GI) tract, along with gut-associated lymphoid tissue (GALT), constitutes the largest lymphatic organ in the human body and forms the biggest surface of contact with the external environment. It is also the most significant source of bacterial and food-derived antigenic material. There is a broad range of reciprocal interactions between the GI tract, intestinal microbiota, increased intestinal permeability, activation of immune-inflammatory response, and the CNS that has crucial implications in brain function and mental health. This intercommunication takes place within the microbiota-gut-immune-glia (MGIG) axis, and glial cells are the main orchestrator of this communication. A broad range of factors, including psychological stress, inflammation, dysbiosis, may compromise the permeability of this barrier. This leads to excessive bacterial translocation and the excessive influx of food-derived antigenic material that contributes to activation of the immune-inflammatory response and depressive psychopathology. This chapter summarizes the role of increased intestinal permeability in MDD and mechanisms of how the "leaky gut" may contribute to immune-inflammatory response in this disorder.

Gut microbiome, liver immunology, and liver diseases

The gut microbiota is a complex and plastic consortium of microorganisms that are intricately connected with human physiology. The liver is a central immunological organ that is particularly enriched in innate immune cells and constantly exposed to circulating nutrients and endotoxins derived from the gut microbiota. The delicate interaction between the gut and liver prevents accidental immune activation against otherwise harmless antigens. Work on the interplay between the gut microbiota and liver has assisted in understanding the pathophysiology of various liver diseases. Of immense importance is the step from high-throughput sequencing (correlation) to mechanistic studies (causality) and therapeutic intervention. Here, we review the gut microbiota, liver immunology, and the interaction between the gut and liver. In addition, the impairment in the gut-liver axis found in various liver diseases is reviewed here, with an emphasis on alcohol-associated liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), and autoimmune liver disease (AILD). On the basis of growing evidence from these preclinical studies, we propose that the gut-liver axis paves the way for targeted therapeutic modalities for liver diseases.

Long-lasting microbial dysbiosis and altered enteric neurotransmitters in adult rats following adolescent binge ethanol exposure

Human alcoholism and ethanol exposure of adult mice cause acute microbial dysbiosis. Adolescent binge drinking is common, but the effect of adolescent ethanol exposure on the adult microbiome and enteric neurotransmitters has not been studied. In the current study, male Wistar rats received adolescent intermittent ethanol (AIE) treatment, and fecal samples were collected on postnatal day (P)54 and P95 for bacterial 16S rRNA amplicon sequencing. Cecal tissue was collected on P95 for analysis of innate immune and neurotransmitter marker expression. At the genus level, AIE treatment altered the relative abundance of several microbes, including decreased relative abundance of Dehalobacterium and CF231 (a member of the Paraprevotellaceae family) that persisted into adulthood. Across aging, the relative abundance of several microbes was altered in both control- and AIE-treated rats. At P95, AIE exposure was associated with increased cecal serotonin levels and reduced choline acetyltransferase gene expression. Taxonomic shifts at P54 and at P95 suggest that AIE causes both immediate and lasting microbial dysbiosis. The lasting microbial dysbiosis was accompanied by alterations of enteric neurotransmitters.

The Gut Microbiome and Alcoholic Liver Disease: Ethanol Consumption Drives Consistent and Reproducible Alteration in Gut Microbiota in Mice

Phenotypic health effects, both positive and negative, have been well studied in association with the consumption of alcohol in humans as well as several other mammals including mice. Many studies have also associated these same health effects and phenotypes to specific members of gut microbiome communities. Here we utilized a chronic plus binge ethanol feed model (Gao-binge model) to explore microbiome community changes across three independent experiments performed in mice. We found significant and reproducible differences in microbiome community assemblies between ethanol-treated mice and control mice on the same diet absent of ethanol. We also identified significant differences in gut microbiota occurring temporally with ethanol treatment. Peak shift in communities was observed 4 days after the start of daily alcohol consumption. We quantitatively identified many of the bacterial genera indicative of these ethanol-induced shifts including 20 significant genera when comparing ethanol treatments with controls and 14 significant genera based on temporal investigation. Including overlap of treatment with temporal shifts, we identified 25 specific genera of interest in ethanol treatment microbiome shifts. Shifts coincide with observed presentation of fatty deposits in the liver tissue, i.e., Alcoholic Liver Disease-associated phenotype. The evidence presented herein, derived from three independent experiments, points to the existence of a common, reproducible, and characterizable "mouse ethanol gut microbiome".

Gut dysbiosis as a driver in alcohol-induced liver injury

Alcohol-related liver disease characterises a broad spectrum of hepatic diseases that result from heavy alcohol use, and include alcohol-related steatosis, steatohepatitis, fibrosis, cirrhosis, and alcoholic hepatitis. Amongst heavy drinkers, progression to more severe forms of alcohol-related liver disease is not universal, with only 20% developing cirrhosis and up to one-third developing alcoholic hepatitis. Non-alcohol-related triggers for severe disease are not well understood, but the intestinal microbiome is thought to be a contributing factor. This review examines the role of the microbiome in mild alcohol-related liver disease, cirrhosis, and alcoholic hepatitis. While most of the literature discusses bacterial dysbiosis, we also discuss the available evidence on fungal (mycobiome) and virome alterations in patients with alcohol-related liver disease. Additionally, we explore the mechanisms by which the microbiome contributes to the pathogenesis of alcohol-related liver disease, including effects on intestinal permeability, bile acid dysregulation, and production of hepatotoxic virulence factors.

Immunological mechanisms and therapeutic targets of fatty liver diseases

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are the two major types of chronic liver disease worldwide. Inflammatory processes play key roles in the pathogeneses of fatty liver diseases, and continuous inflammation promotes the progression of alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH). Although both ALD and NAFLD are closely related to inflammation, their respective developmental mechanisms differ to some extent. Here, we review the roles of multiple immunological mechanisms and therapeutic targets related to the inflammation associated with fatty liver diseases and the differences in the progression of ASH and NASH. Multiple cell types in the liver, including macrophages, neutrophils, other immune cell types and hepatocytes, are involved in fatty liver disease inflammation. In addition, microRNAs (miRNAs), extracellular vesicles (EVs), and complement also contribute to the inflammatory process, as does intertissue crosstalk between the liver and the intestine, adipose tissue, and the nervous system. We point out that inflammation also plays important roles in promoting liver repair and controlling bacterial infections. Understanding the complex regulatory process of disrupted homeostasis during the development of fatty liver diseases may lead to the development of improved targeted therapeutic intervention strategies.

A review of potential microbiome-gut-brain axis mediated neurocognitive conditions in persons living with HIV

The microbiome-gut-brain axis, or the various interactions between the gut microbiome and the brain, has been of recent interest in the context of precision medicine research for a variety of disease states. Persons living with human immunodeficiency virus (PLWH) experience higher degrees of neurocognitive decline than the general population, correlating with a disruption of the normal gut microbiome composition (i.e. dysbiosis). While the nature of this correlation remains to be determined, there is the potential that the microbiome-gut-brain axis contributes to the progression of this disease. Previous research has established that the pathology associated with HIV induces alterations in the composition of gut microbiome, including a shift from Bacteroides to Prevotella dominance, and compromises gut barrier integrity, which may promote microbial translocation and consequent systemic inflammation and exacerbation of neuroinflammation. Further, though the use of antiretroviral therapy has been found to partially counteract HIV-related dysbiosis, it may also induce its own dysbiosis patterns, presenting a unique challenge for this research. More recent research has suggested the gut microbiome as a target for therapeutic interventions to improve symptoms associated with a variety of disease states, including HIV. Early findings are promising and warrant further research regarding the gut microbiome as a potential modifiable factor to improve health outcomes for PLWH. This review will discuss the current knowledge concerning the neuropathogenesis of HIV in the brain, role of the gut microbiome in neuroinflammation, and the relationship between HIV-status and the gut microbiome, followed by a conclusion that synthesizes this information within the context of the microbiome-gut-brain axis among PLWH. This review will also highlight the limitations of existing studies and propose future directions of this research.

Microbiota reprogramming for treatment of alcohol-related liver disease

In the past decade knowledge has expanded regarding the importance of the gut microbiota in maintaining intestinal homeostasis and overall health. During this same time, we have also gained appreciation for the role of the gut-liver axis in the development of liver diseases. Alcohol overconsumption is one of the leading causes of liver failure globally. However, not all people with alcohol use disorder progress to advanced stages of liver disease. With advances in technology to investigate the gut microbiome and metabolome, we are now beginning to delineate alcohol's effects on the gut microbiome in relation to liver disease. This review presents our current understanding on the role of the gut microbiota during alcohol exposure, and various therapeutic attempts that have been made to reprogram the gut microbiota with the goal of alleviating alcoholic-related liver disease.

Intestinal Virome in Patients With Alcoholic Hepatitis

BACKGROUND AND AIMS

Alcoholic hepatitis (AH) is a severe manifestation of alcohol-associated liver disease (ALD) with high mortality. Although gut bacteria and fungi modulate disease severity, little is known about the effects of the viral microbiome (virome) in patients with ALD.

APPROACH AND RESULTS

We extracted virus-like particles from 89 patients with AH who were enrolled in a multicenter observational study, 36 with alcohol use disorder (AUD), and 17 persons without AUD (controls). Virus-like particles from fecal samples were fractionated using differential filtration techniques, and metagenomic sequencing was performed to characterize intestinal viromes. We observed an increased viral diversity in fecal samples from patients with ALD, with the most significant changes in samples from patients with AH. Escherichia-, Enterobacteria-, and Enterococcus phages were over-represented in fecal samples from patients with AH, along with significant increases in mammalian viruses such as Parvoviridae and Herpesviridae. Antibiotic treatment was associated with higher viral diversity. Specific viral taxa, such as Staphylococcus phages and Herpesviridae, were associated with increased disease severity, indicated by a higher median Model for End-Stage Liver Disease score, and associated with increased 90-day mortality.

CONCLUSIONS

In conclusion, intestinal viral taxa are altered in fecal samples from patients with AH and associated with disease severity and mortality. Our study describes an intestinal virome signature associated with AH.

Toll-Like Receptor 4 Signaling and Drug Addiction

The emphasis of neuronal alterations and adaptations have long been the main focus of the studies of the mechanistic underpinnings of drug addiction. Recent studies have begun to appreciate the role of innate immune system, especially toll-like receptor 4 (TLR4) signaling in drug reward-associated behaviors and physiology. Drugs like opioids, alcohol and psychostimulants activate TLR4 signaling and subsequently induce proinflammatory responses, which in turn contributes to the development of drug addiction. Inhibition of TLR4 or its downstream effectors attenuated the reinforcing effects of opioids, alcohol and psychostimulants, and this effect is also involved in the withdrawal and relapse-like behaviors of different drug classes. However, conflicting results also argue that TLR4-related immune response may play a minimal part in drug addiction. This review discussed the preclinical evidence that whether TLR4 signaling is involved in multiple drug classes action and the possible mechanisms underlying this effect. Moreover, clinical studies which examined the potential efficacy of immune-base pharmacotherapies in treating drug addiction are also discussed.

Implications of the Human Gut-Brain and Gut-Cancer Axes for Future Nanomedicine

Recent clinical and pathological evidence have implicated the gut microbiota as a nexus for modulating the homeostasis of the human body, impacting conditions from cancer and dementia to obesity and social behavior. The connections between microbiota and human diseases offer numerous opportunities in medicine, most of which have limited or no therapeutic solutions available. In light of this paradigm-setting trend in science, this review aims to provide a comprehensive and timely summary of the mechanistic pathways governing the gut microbiota and their implications for nanomedicines targeting cancer and neurodegenerative diseases. Specifically, we discuss in parallel the beneficial and pathogenic relationship of the gut microbiota along the gut-brain and gut-cancer axes, elaborate on the impact of dysbiosis and the gastrointestinal corona on the efficacy of nanomedicines, and highlight a molecular mimicry that manipulates the universal cross-β backbone of bacterial amyloid to accelerate neurological disorders. This review further offers a forward-looking section on the rational design of cancer and dementia nanomedicines exploiting the gut-brain and gut-cancer axes.

You Talking to Me? Says the Enteric Nervous System (ENS) to the Microbe. How Intestinal Microbes Interact with the ENS

Mammalian organisms form intimate interfaces with commensal and pathogenic gut microorganisms. Increasing evidence suggests a close interaction between gut microorganisms and the enteric nervous system (ENS), as the first interface to the central nervous system. Each microorganism can exert a different effect on the ENS, including phenotypical neuronal changes or the induction of chemical transmitters that interact with ENS neurons. Some pathogenic bacteria take advantage of the ENS to create a more suitable environment for their growth or to promote the effects of their toxins. In addition, some commensal bacteria can affect the central nervous system (CNS) by locally interacting with the ENS. From the current knowledge emerges an interesting field that may shape future concepts on the pathogen-host synergic interaction. The aim of this narrative review is to report the current findings regarding the inter-relationships between bacteria, viruses, and parasites and the ENS.

Transcriptional signatures of the small intestinal mucosa in response to ethanol in transgenic mice rich in endogenous n3 fatty acids

The intestine interacts with many factors, including dietary components and ethanol (EtOH), which can impact intestinal health. Previous studies showed that different types of dietary fats can modulate EtOH-induced changes in the intestine; however, mechanisms underlying these effects are not completely understood. Here, we examined intestinal transcriptional responses to EtOH in WT and transgenic fat-1 mice (which endogenously convert n6 to n3 polyunsaturated fatty acids [PUFAs]) to identify novel genes and pathways involved in EtOH-associated gut pathology and discern the impact of n3 PUFA enrichment. WT and fat-1 mice were chronically fed EtOH, and ileum RNA-seq and bioinformatic analyses were performed. EtOH consumption led to a marked down-regulation of genes encoding digestive and xenobiotic-metabolizing enzymes, and transcription factors involved in developmental processes and tissue regeneration. Compared to WT, fat-1 mice exhibited a markedly plastic transcriptome response to EtOH. Cell death, inflammation, and tuft cell markers were downregulated in fat-1 mice in response to EtOH, while defense responses and PPAR signaling were upregulated. This transcriptional reprogramming may contribute to the beneficial effects of n3 PUFAs on EtOH-induced intestinal pathology. In summary, our study provides a reference dataset of the intestinal mucosa transcriptional responses to chronic EtOH exposure for future hypothesis-driven mechanistic studies.

Modulation of the Gut Microbiome and Obesity Biomarkers by Lactobacillus Plantarum KC28 in a Diet-Induced Obesity Murine Model

Lactobacillus plantarum KC28 showed a beneficial (anti-obesity) effect in a diet-induced obese (DIO) C57BL/6 murine model receiving an intermediate high-fat diet (IF). This diet was selected for probiotic studies by prior comparisons of different combinations of basic (carbohydrate, protein and fat) components for optimized induction of dietary obesity in a murine model. Prior selection of Lact. plantarum strain KC28 was based on different physiological tests for safety and functionality including cell line adhesion and anti-adipogenic activity. The strain was administered at 5.0 × 10⁹ CFU/mouse/day to the DIO mice (control mice received a normal diet). The anti-obesity effect of KC28 and the well-known probiotic strains Lact. rhamnosus GG (LGG) and Lact. plantarum 299v was assessed over 12 weeks. Xenical served as anti-obesity control. The high-fat diet groups receiving strains KC28 and LGG and the control Xenical group showed significant weight loss and notable changes in some obesity-related biomarkers in the liver (significant up-regulation of PGC1-α and CPT1-α only by KC28; p < 0.05) and mesenteric adipose tissue (significant down-regulation of ACOX-1, PPAR-γ, and FAS; KC28 p < 0.001 for PPAR-γ and FAS), compared with the IF control. Favourable changes in the studied biomarkers suggest a similar beneficial influence of Lact. plantarum KC28 on the alleviation of obesity comparable with that of the two well-studied probiotic strains, LGG and 299v. This probably resulted from a modulation in the cecal microbiota of the IF group by either probiotic strain, yet in a different manner, showing a highly significant increase in the families Desulfovibrionaceae and Lactobacillaceae only in the group receiving Lact. plantarum KC28.

Opioid agonist and antagonist use and the gut microbiota: associations among people in addiction treatment

Murine models suggest that opioids alter the gut microbiota, which may impact opioid tolerance and psychopathology. We examined how gut microbiota characteristics related to use of opioid agonists and antagonists among people receiving outpatient addiction treatment. Patients (n = 46) collected stool samples and were grouped by use of opioid agonists (heroin, prescription opioids), antagonists (naltrexone), agonist-antagonist combinations (buprenorphine-naloxone), or neither agonists nor antagonists within the month before enrollment. We sequenced the V4 region of the 16S rRNA gene using Illumina MiSeq to examine how alpha diversity, enterotypes, and relative abundance of bacterial genera varied by opioid agonist and antagonist exposures. Compared to 31 participants who used neither agonists nor antagonists, 5 participants who used opioid agonists (without antagonists) had lower microbiota diversity, Bacteroides enterotypes, and lower relative abundance of Roseburia, a butyrate producing genus, and Bilophila, a bile acid metabolizing genus. There were no differences in gut microbiota features between those using agonist + antagonists (n = 4), antagonists only (n = 6), and neither agonists nor antagonists. Similar to murine morphine exposure models, opioid agonist use was associated with lower microbiota diversity. Lower abundance of Roseburia and Bilophila may relate to the gut inflammation/permeability and dysregulated bile acid metabolism observed in opioid-exposed mice.

Intestinal permeability, microbial translocation, changes in duodenal and fecal microbiota, and their associations with alcoholic liver disease progression in humans

BACKGROUND

Animal data suggest a role of the gut-liver axis in progression of alcoholic liver disease (ALD), but human data are scarce especially for early disease stages.

METHODS

We included patients with alcohol use disorder (AUD) who follow a rehabilitation program and matched healthy controls. We determined intestinal epithelial and vascular permeability (IP) (using urinary excretion of ⁵¹Cr-EDTA, fecal albumin content, and immunohistochemistry in distal duodenal biopsies), epithelial damage (histology, serum iFABP, and intestinal gene expression), and microbial translocation (Gram - and Gram + serum markers by ELISA). Duodenal mucosa-associated microbiota and fecal microbiota were analyzed by 16 S rRNA sequencing. ALD was staged by Fibroscan® (liver stiffness, controlled attenuation parameter) in combination with serum AST, ALT, and CK18-M65.

RESULTS

Only a subset of AUD patients had increased ⁵¹Cr-EDTA and fecal albumin together with disrupted tight junctions and vasculature expression of plasmalemma Vesicle-Associated Protein-1. The so-defined increased intestinal permeability was not related to changes of the duodenal microbiota or alterations of the intestinal epithelium but associated with compositional changes of the fecal microbiota. Leaky gut alone did not explain increased microbial translocation in AUD patients. By contrast, duodenal dysbiosis with a dominance shift toward specific potential pathogenic bacteria genera (Streptococcus, Shuttleworthia, Rothia), increased IP and elevated markers of microbial translocation characterized AUD patients with progressive ALD (steato-hepatitis, steato-fibrosis).

CONCLUSION

Progressive ALD already at early disease stages is associated with duodenal mucosa-associated dysbiosis and elevated microbial translocation. Surprisingly, such modifications were not linked with increased IP. Rather, increased IP appears related to fecal microbiota dysbiosis.

From correlation to causality: the case of Subdoligranulum

Gut microbes are considered as major factors contributing to human health. Nowadays, the vast majority of the data available in the literature are mostly exhibiting negative or positive correlations between specific bacteria and metabolic parameters. From these observations, putative detrimental or beneficial effects are then inferred. Akkermansia muciniphila is one of the unique examples for which the correlations with health benefits have been causally validated in vivo in rodents and humans. In this study, based on available metagenomic data in overweight/obese population and clinical variables that we obtained from two cohorts of individuals (n = 108) we identified several metagenomic species (MGS) strongly associated with A. muciniphila with one standing out: Subdoligranulum. By analyzing both qPCR and shotgun metagenomic data, we discovered that the abundance of Subdoligranulum was correlated positively with microbial richness and HDL-cholesterol levels and negatively correlated with fat mass, adipocyte diameter, insulin resistance, levels of leptin, insulin, CRP, and IL6 in humans. Therefore, to further explore whether these strong correlations could be translated into causation, we investigated the effects of the unique cultivated strain of Subdoligranulum (Subdoligranulum variabile DSM 15176 ^T) in obese and diabetic mice as a proof-of-concept. Strikingly, there were no significant difference in any of the hallmarks of obesity and diabetes measured (e.g., body weight gain, fat mass gain, glucose tolerance, liver weight, plasma lipids) at the end of the 8 weeks of treatment. Therefore, the absence of effect following the supplementation with S. variabile indicates that increasing the intestinal abundance of this bacterium is not translated into beneficial effects in mice. In conclusion, we demonstrated that despite the fact that numerous strong correlations exist between a given bacteria and health, proof-of-concept experiments are required to be further validated or not in vivo. Hence, an urgent need for causality studies is warranted to move from human observations to preclinical validations.

The Gut Barrier, Intestinal Microbiota, and Liver Disease: Molecular Mechanisms and Strategies to Manage

Liver disease encompasses pathologies as non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, alcohol liver disease, hepatocellular carcinoma, viral hepatitis, and autoimmune hepatitis. Nowadays, underlying mechanisms associating gut permeability and liver disease development are not well understood, although evidence points to the involvement of intestinal microbiota and their metabolites. Animal studies have shown alterations in Toll-like receptor signaling related to the leaky gut syndrome by the action of bacterial lipopolysaccharide. In humans, modifications of the intestinal microbiota in intestinal permeability have also been related to liver disease. Some of these changes were observed in bacterial species belonging Roseburia, Streptococcus, and Rothia. Currently, numerous strategies to treat liver disease are being assessed. This review summarizes and discusses studies addressed to determine mechanisms associated with the microbiota able to alter the intestinal barrier complementing the progress and advancement of liver disease, as well as the main strategies under development to manage these pathologies. We highlight those approaches that have shown improvement in intestinal microbiota and barrier function, namely lifestyle changes (diet and physical activity) and probiotics intervention. Nevertheless, knowledge about how such modifications are beneficial is still limited and specific mechanisms involved are not clear. Thus, further in-vitro, animal, and human studies are needed.

Longitudinal gut microbiome changes in alcohol use disorder are influenced by abstinence and drinking quantity

Many patients with alcohol use disorder (AUD) consume alcohol chronically and in large amounts that alter intestinal microbiota, damage the gastrointestinal tract, and thereby injure other organs via malabsorption and intestinal inflammation. We hypothesized that alcohol consumption and subsequent abstinence would change the gut microbiome in adults admitted to a treatment program. Stool and oral specimens, diet data, gastrointestinal assessment scores, anxiety, depression measures and drinking amounts were collected longitudinally for up to 4 weeks in 22 newly abstinent inpatients with AUD who were dichotomized as less heavy drinkers (LHD, <10 drinks/d) and very heavy drinkers (VHD, 10 or more drinks/d). Next-generation 16 S rRNA gene sequencing was performed to measure the gut and oral microbiome at up to ten time points/subject and LHD and VHD were compared for change in principal components, Shannon diversity index and specific genera. The first three principal components explained 46.7% of the variance in gut microbiome diversity across time and all study subjects, indicating the change in gut microbiome following abstinence. The first time point was an outlier in three-dimensional principal component space versus all other time points. The gut microbiota in LHD and VHD were significantly dissimilar in change from day 1 to day 5 (p = .03) and from day 1 to week 3 (p = .02). The VHD drinking group displayed greater change from baseline. The Shannon diversity index of the gut microbiome changed significantly during abstinence in five participants. In both groups, the Shannon diversity was lower in the oral microbiome than gut. Ten total genera were shared between oral and stool in the AUD participants. These data were compared with healthy controls from the Human Microbiome Project to investigate the concept of a core microbiome. Rapid changes in gut microbiome following abstinence from alcohol suggest resilience of the gut microbiome in AUD and reflects the benefits of refraining from the highest levels of alcohol and potential benefits of abstinence.

Changes in Circulating Metabolome Precede Alcohol-Related Diseases in Middle-Aged Men: A Prospective Population-Based Study With a 30-Year Follow-Up

BACKGROUND

Heavy alcohol use has been associated with altered circulating metabolome. We investigated whether changes in the circulating metabolome precede incident diagnoses of alcohol-related diseases.

METHODS

This is a prospective population-based cohort study where the participants were 42- to 60-year-old males at baseline (years 1984 to 1989). Subjects who received a diagnosis for an alcohol-related disease during the follow-up were defined as cases (n = 92, mean follow-up of 13.6 years before diagnosis). Diagnoses were obtained through linkage with national health registries. We used 2 control groups: controls who self-reported similar levels of alcohol use as compared to cases at baseline (alcohol-controls, n = 92), and controls who self-reported only light drinking at baseline (control-controls, n = 90). A nontargeted metabolomics analysis of baseline serum samples was performed.

RESULTS

There were significant differences between the study groups in the baseline serum levels of 64 metabolites: in amino acids (e.g., glutamine [FDR-corrected q-value = 0.0012]), glycerophospholipids (e.g., lysophosphatidylcholine 16:1 [q = 0.0008]), steroids (e.g., cortisone [q = 0.00001]), and fatty acids (e.g., palmitoleic acid [q = 0.0031]). The main finding was that after controlling for baseline levels of self-reported alcohol use and the biomarker of alcohol use, gamma-glutamyl transferase, and when compared to both alcohol-control and control-control group, the alcohol-case group had lower serum levels of asparagine (Cohen's d = -0.48 [95% CI -0.78 to -0.19] and d = -0.49 [-0.78 to -0.19], respectively) and serotonin (d = -0.45 [-0.74 to -0.15], and d = -0.46 [-0.75 to -0.16], respectively), with no difference between the two control groups (asparagine d = 0.00 [-0.29 to 0.29] and serotonin d = -0.01 [-0.30 to 0.29]).

CONCLUSIONS

Changes in the circulating metabolome, especially lower serum levels of asparagine and serotonin, are associated with later diagnoses of alcohol-related diseases, even after adjustment for the baseline level of alcohol use.

Intestinal permeability and bacterial translocation in patients with liver disease, focusing on alcoholic aetiology: methods of assessment and therapeutic intervention

Increased bacterial translocation (BT) across the gut barrier due to greater intestinal permeability (IP) is seen across a range of conditions, including alcohol-related liver disease (ArLD). The phenomenon of BT may contribute to both the pathogenesis and the development of complications in ArLD. There are a number of methods available to assess IP and in this review we look at their various advantages and limitations. The knowledge around BT and IP in ArLD is also reviewed, as well as the therapeutic strategies currently in use and in development.

The combined effects of probiotics and restricted calorie diet on the anthropometric indices, eating behavior, and hormone levels of obese women with food addiction a randomized clinical trial

BACKGROUND AND AIM

Food addiction (FA) is an important contributor to obesity. Alterations in gut microbiota (GM) diversity and composition have also been proposed to play a pivotal role in obesity pathogenesis. This trial aimed to assess the effects of probiotic supplementation on the anthropometric indices, eating behavior, and hormone levels of obese women with FA.

METHODS

This randomized, double-blind, placebo-controlled clinical trial was conducted among obese women with FA. Participants (n = 62) received a restricted calorie diet (RCD) plus either probiotic, or placebo for 12 weeks. Anthropometric measurements, biochemical markers, eating behavior and appetite were assessed during the study period.

RESULTS

Probiotics administration significantly reduced weight, body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR), body fat percentage (BFP), and trunk fat percentage (TFP) compared to the placebo group (p < 0.001). Also, a significant improvement was observed in eating behavior in the probiotic group compared to the placebo group (p < 0.001).Serum levels of oxytocin increased and NPY decreased significantly in the probiotic group compared to the placebo group (p = 0.02, p = 0.002, respectively). Moreover, leptin level significantly decreased in the probiotic group compared to the baseline values (p < 0.001), while probiotics did not cause a greater significant reduction in leptin level, compared to the placebo group.

CONCLUSION

Multi-probiotic supplementation may have beneficial effects on anthropometric indices, eating behavior, and some appetite-regulating hormones in obese women with FA.Trial registration: Iranian Registry of Clinical Trials identifier: IRCT20131228015968N5.

Innate lymphocytes: pathogenesis and therapeutic targets of liver diseases and cancer

The liver is a lymphoid organ with unique immunological properties, particularly, its predominant innate immune system. The balance between immune tolerance and immune activity is critical to liver physiological functions and is responsible for the sensitivity of this organ to numerous diseases, including hepatotropic virus infection, alcoholic liver disease, nonalcoholic fatty liver disease, autoimmune liver disease, and liver cancer, which are major health problems globally. In the past decade, with the discovery of liver-resident natural killer cells, the importance of innate lymphocytes with tissue residency has gradually become the focus of research. In this review, we address the current knowledge regarding hepatic innate lymphocytes with unique characteristics, including NK cells, ILC1/2/3s, NKT cells, γδ T cells, and MAIT cells, and their potential roles in liver homeostasis maintenance and the progression of liver diseases and cancer. A better understanding of the immunopathogenesis of hepatic innate lymphocytes will be helpful for proposing effective treatments for liver diseases and cancer.

Microbiota Analysis of Chickens Raised Under Stressed Conditions

A substantial progress has been made toward understanding stress-associated gut and extraintestinal microbiota. However, a comprehensive understanding of the extraintestinal microbiota of chickens raised under stressed conditions is lacking. In this study, chickens were raised on a wire-floor model to induce stress, and the microbiota in the gut (ceca) and extraintestinal sites (blood, femur, and tibia) were characterized at different ages (1, 17, and 56 days) using 16S rRNA gene microbiota profiling. Open reference OTU picking showed extraintestinal sites had a significantly higher number of unassigned OTUs compared to ceca across all ages of chickens. Extraintestinal sites of all ages, irrespective of body sites, as well as ceca of 1 day-old chickens had significantly lower alpha diversity than ceca of older chickens. Intriguingly, bacterial diversity (alpha and beta) and OTU interaction network analysis showed relatively stable bacterial composition within the extraintestinal sites of chickens regardless of age and sites compared to ceca. Furthermore, assessment using UniFrac distance suggested the gut as a possible source of extraintestinal bacteria. Lastly, LEfSe analysis showed that both commensal and pathogenic bacteria were translocated into the extraintestinal tissues and organs under the stress. Extraintestinal sites have highly abundant novel taxa that need to be further explored. In ovo microbiota colonization and/or translocation of circulating maternal blood microbiota into ovarian follicles might be the source of intestinal and extraintestinal microbiota in 1 day-old chickens. Our comprehensive microbiota data including extraintestinal sites in reference to gut provide unique insights into microbiota of chickens raised under stressed conditions, which may be relevant in other animal species as well.

Alcohol use disorder and circulating cytokines: A systematic review and meta-analysis

There has been emerging interest in the role of the immune system in the pathophysiology of alcohol use disorder (AUD) given alcohol consumption stimulates immune cells to secrete peripheral pro- and anti-inflammatory cytokines. We conducted a systematic review and meta-analysis to determine whether an abnormal inflammatory cytokine profile exists in AUD patients compared to controls and whether cytokine levels were correlated with behavioural and psychiatric variables. Using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-analyses) guidelines, a comprehensive search of electronic databases (MEDLINE, EMBASE, Web of Science Core Collection and the Cochrane Library) was conducted, for AUD-related terms in combination with cytokine-related terms. Patients had to meet established criteria for AUD and be compared with healthy controls. A critical appraisal was completed using the Newcastle-Ottawa Scale. Twenty-four papers met the inclusionary criteria with 46 serum or plasma cytokines measured without immune stimulation whereby 17 studies had sufficient data for inclusion in the meta-analysis. Collectively, AUD patients had greater cytokine concentrations than control patients g = 0.85 [ 95% CI 0.42, 1.29]. Differences in cytokine concentrations between AUD patients and controls varied within-study by stage of illness (R₍₂₎² = 19.56%). The greatest differences were reported when AUD patients were engaging in active drinking g = 0.96 [0.49, 1.43] or were in alcohol withdrawal g = 1.25 [0.71, 1.80]. Baseline findings were moderated within and between studies by cytokine identity R₍₂₎² = 51.10%; R₍₃₎² = 44.89%. Cytokine concentrations were not significantly correlated with self-reported craving for alcohol, but were with alcohol consumption r = 0.22 [-0.05, 0.46]. The relationship between cytokine concentration and consumption was moderated by cytokine identity (R₍₂₎² = 100.00%; R₍₃₎² = 100.00%), and sample age (R₍₂₎² = 0.00%; R₍₃₎² = 95.76%). There is sufficient evidence to support the presence of an abnormal circulating cytokine profile in AUD which may vary with respect to the different stages of AUD illness.

Role of toll-like receptor 7 (TLR7) in voluntary alcohol consumption

Overactivation of neuroimmune signaling has been linked to excessive ethanol consumption. Toll-like receptors (TLRs) are a major component of innate immune signaling and initiate anti- and pro-inflammatory responses via intracellular signal transduction cascades. TLR7 is upregulated in post-mortem brain tissue from humans with alcohol use disorder (AUD) and animals with prior exposure to ethanol. Despite this evidence, the role of TLR7 in the regulation of voluntary ethanol consumption has not been studied. We test the hypothesis that TLR7 activation regulates voluntary ethanol drinking behavior by administering a TLR7 agonist (R848) during an intermittent access drinking procedure in mice. Acute activation of TLR7 reduced ethanol intake, preference, and total fluid intake due, at least in part, to an acute sickness response. However, chronic pre-treatment with R848 resulted in tolerance to the adverse effects of the drug and a subsequent increase in ethanol consumption. To determine the molecular machinery that mediates these behavioral changes, we evaluated gene expression after acute and chronic TLR7 activation. We found that acute TLR7 activation produces brain region specific changes in expression of immune pathway genes, whereas chronic TLR7 activation causes downregulation of TLRs and blunted cytokine induction, suggesting molecular tolerance. Our results demonstrate a novel role for TLR7 signaling in regulating voluntary ethanol consumption. Taken together, our findings suggest TLR7 may be a viable target for development of therapies to treat AUD.

Characteristics of intestinal bacteria with fatty liver diseases and cirrhosis

Non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD) are significant health burdens worldwide with a substantial rise in prevalence. Both can progress to liver cirrhosis. Recent studies have shown that the gut microbiome was associated with NAFLD/AFLD development and progression. The present review focuses on the characteristics of bacteria in NAFLD, AFLD and liver cirrhosis. The similarities and differences of intestinal bacteria are discussed. This study reviews the existing literatures on the microbiota, fatty liver disease, and liver cirrhosis based on Pubmed database. The study showed NAFLD was characterized by increased amounts of Lachnospiraceae from the phylum Firmicutes and Roseburia from the Lachnospiraceae family, and the proportion of Enterobacteria and Proteobacteria was increased after alcohol intake. Reduced Bacteroidetes was observed in cirrhosis. Microbiota can improve or aggravate the above liver diseases through several mechanisms, like increasing liver lipid metabolism, increasing alcohol production, increasing intestinal permeability, bacterial translocation, intestinal bacterial overgrowth, enteric dysbiosis, and impairing bile secretion. Different hepatic diseases owned different intestinal bacterial characters. Microbiota can improve or aggravate three kinds of liver diseases through several mechanisms. However, the depletion of these bacteria is needed to verify their role in liver disease.

Alcohol use alters the colonic mucosa-associated gut microbiota in humans

Alcohol misuse is a risk factor for many adverse health outcomes. Alcohol misuse has been associated with an imbalance of gut microbiota in preclinical models and alcoholic diseases. We hypothesized that daily alcohol use would change the community composition and structure of the human colonic gut microbiota. Thirty-four polyp-free individuals donated 97 snap-frozen colonic biopsies. Microbial DNA was sequenced for the 16S ribosomal RNA gene hypervariable region 4. The SILVA database was used for operational taxonomic unit classification. Alcohol use was assessed using a food frequency questionnaire. We compared the biodiversity and relative abundance of the taxa among never drinkers (ND, n = 9), former drinkers (FD, n = 10), current light drinkers (LD, <2 drinks daily, n = 9), and current heavy drinkers (HD, ≥2 drinks daily, n = 6). False discovery rate-adjusted P values (q values) < .05 indicated statistical significance. HD had the lowest α diversity (Shannon index q value < 0.001), and HD's microbial composition differed the most from the other groups (P value = .002). LD had the highest relative abundance of Akkermansia (q values < 0.001). HD had the lowest relative abundance of Subdoligranulum, Roseburia, and Lachnospiraceaeunc91005 but the highest relative abundance of Lachnospiraceaeunc8895 (all q values < 0.05). The multivariable negative binomial regression model supported these observations. ND and FD had a similar microbial profile. Heavy alcohol use was associated with impaired gut microbiota that may partially mediate its effect on health outcomes.

Alcohol Addiction, Gut Microbiota, and Alcoholism Treatment: A Review

Alcohol addiction is a leading risk factor for personal death and disability. In 2016, alcohol use caused 2.2% of female deaths and 6.8% of male deaths, and disability-adjusted life years (DALYs) were 2.3% in female and 8.9% in male. Individuals with alcohol use disorder are at high risk of anxiety, depression, impaired cognition performance, and illicit drug use and are comorbid with liver disease, such as alcoholic hepatitis and liver cirrhosis, which is a major cause of personal death and disability worldwide. Psychological interventions, such as cognitive behavior therapy and motivational interviewing, as well as medical treatments, such as disulfiram, naltrexone, acamprosate, and nalmefene, are used for the treatment of alcohol addiction in Europe and the United States. However, the effect of current interventions is limited, and the need for additional interventions is substantial. Alcohol use impairs the intestinal barrier and causes changes to the intestinal permeability as well as the gut microbiota composition. Emerging studies have tried to reveal the role of the gut–brain axis among individuals with alcohol use disorder with or without alcohol liver disease. Bacterial products penetrate the impaired intestinal barrier and cause central inflammation; changes to the gut microbiota impair enterohepatic circulation of bile acids; alcohol abuse causes shortage of vital nutrients such as thiamine. Several studies have suggested that probiotics, through either oral administration or fecal microbiota transplantation, increased intestinal levels of potentially beneficial bacteria such as bifidobacteria and lactobacilli, improving the levels of liver-associated enzymes in patients with mild alcoholic hepatitis, and demonstrating beneficial psychotropic effects on anxiety and depression. In addition to medications for alcohol addiction, gene editing therapy such as clustered regularly interspaced short palindromic repeats (CRISPRs) may be another potential research target. Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), which are associated with ADH and ALDH genes, are major enzymes involved in alcohol metabolism, and gene editing approaches may have the potential to directly modify specific genes to treat alcoholism caused by genetic defects. Further research is needed to study the effect of the combined treatment for alcohol addiction.

Neuroprotective effects of p62(SQSTM1)-engineered lactic acid bacteria in Alzheimer's disease: a pre-clinical study

Alzheimer's disease (AD) is a progressive neurodegeneration characterized by neuron death ending in memory and cognitive decline. A major concern in AD research is the identification of new therapeutics that could prevent or delay the onset of the disorder, with current treatments being effective only in reducing symptoms. In this perspective, the use of engineered probiotics as therapeutic tools for the delivery of molecules to eukaryotic cells is finding application in several disorders. This work introduces a new strategy for AD treatment based on the use of a Lactobacilluslactis strain carrying one plasmid (pExu) that contains a eukaryotic expression cassette encoding the human p62 protein. 3xTg-AD mice orally administered with these bacteria for two months showed an increased expression of endogenous p62 in the brain, with a protein delivery mechanism involving both lymphatic vessels and neural terminations, and positive effects on the major AD hallmarks. Mice showed ameliorated memory, modulation of the ubiquitin-proteasome system and autophagy, reduced levels of amyloid peptides, and diminished neuronal oxidative and inflammatory processes. Globally, we demonstrate that these extremely safe, non-pathogenic and non-invasive bacteria used as delivery vehicles for the p62 protein represent an innovative and realistic therapeutic approach in AD.

Modulation of Gut Microbiota in Korean Navy Trainees following a Healthy Lifestyle Change

Environmental factors can influence the composition of gut microbiota, but understanding the combined effect of lifestyle factors on adult gut microbiota is limited. Here, we investigated whether changes in the modifiable lifestyle factors, such as cigarette smoking, alcohol consumption, sleep duration, physical exercise, and body mass index affected the gut microbiota of Korean navy trainees. The navy trainees were instructed to stop smoking and alcohol consumption and follow a sleep schedule and physical exercise regime for eight weeks. For comparison, healthy Korean civilians, who had no significant change in lifestyles for eight weeks were included in this study. A total of 208 fecal samples were collected from navy trainees (n = 66) and civilians (n = 38) at baseline and week eight. Gut flora was assessed by sequencing the highly variable region of the 16S rRNA gene. The α-and β -diversity of gut flora of both the test and control groups were not significantly changed after eight weeks. However, there was a significant difference among individuals. Smoking had a significant impact in altering α-diversity. Our study showed that a healthy lifestyle, particularly cessation of smoking, even in short periods, can affect the gut microbiome by enhancing the abundance of beneficial taxa and reducing that of harmful taxa.

Antibiotic-induced disruption of commensal microbiome linked to increases in binge-like ethanol consumption behavior

Research focusing on the gut-brain axis is growing, but the interplay of ethanol (alcohol molecule), the gut microbiome, the brain and behavior is poorly understood. In the current study, we remodeled the gut microbiota by providing adult male C57BL/6J mice with a non-absorbable antibiotic cocktail (ABX) in the drinking water and tested ethanol consumption behavior in a binge-like "Drinking in the Dark" model. Notably, 2 weeks of ABX pre-treatment significantly increased ethanol consumption during the 6 weeks of ethanol exposure in the DID paradigm. ABX treatment also appeared to prevent anxiety-like behavior during ethanol withdrawal period. ABX-treated mice expressed reduced bacterial diversity and modified microbiota compositions within cecal samples. There were drastically reduced levels of commensal Firmicutes and increases in the Bacteroidetes and Verrucomicrobia populations. Importantly, the relative abundance of Firmicutes inversely correlated to ethanol intake levels regardless of antibiotic treatment, whereas Bacteroidetes and Verrucomicrobia populations negatively correlated to ethanol intake levels. This is the first report demonstrating that ABX-induced disruption of the gut commensal microbiota leads to increased ethanol consumption in mice. This work reveals an important relationship between the gut microbiota and ethanol consumption behavior and supports the use of microbial-targeted approaches to study gut-brain interactions during alcohol use disorder.

Liver Steatosis, Gut-Liver Axis, Microbiome and Environmental Factors. A Never-Ending Bidirectional Cross-Talk

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and parallels comorbidities such as obesity, metabolic syndrome, dyslipidemia, and diabetes. Recent studies describe the presence of NAFLD in non-obese individuals, with mechanisms partially independent from excessive caloric intake. Increasing evidences, in particular, point towards a close interaction between dietary and environmental factors (including food contaminants), gut, blood flow, and liver metabolism, with pathways involving intestinal permeability, the composition of gut microbiota, bacterial products, immunity, local, and systemic inflammation. These factors play a critical role in the maintenance of intestinal, liver, and metabolic homeostasis. An anomalous or imbalanced gut microbial composition may favor an increased intestinal permeability, predisposing to portal translocation of microorganisms, microbial products, and cell wall components. These components form microbial-associated molecular patterns (MAMPs) or pathogen-associated molecular patterns (PAMPs), with potentials to interact in the intestine lamina propria enriched in immune cells, and in the liver at the level of the immune cells, i.e., Kupffer cells and stellate cells. The resulting inflammatory environment ultimately leads to liver fibrosis with potentials to progression towards necrotic and fibrotic changes, cirrhosis. and hepatocellular carcinoma. By contrast, measures able to modulate the composition of gut microbiota and to preserve gut vascular barrier might prevent or reverse NAFLD.

Gut microbiota alterations are distinct for primary colorectal cancer and hepatocellular carcinoma

Colorectal cancer (CRC) and hepatocellular carcinoma (HCC) are the second and third most common causes of death by cancer, respectively. The etiologies of the two cancers are either infectious insult or due to chronic use of alcohol, smoking, diet, obesity and diabetes. Pathological changes in the composition of the gut microbiota that lead to intestinal inflammation are a common factor for both HCC and CRC. However, the gut microbiota of the cancer patient evolves with disease pathogenesis in unique ways that are affected by etiologies and environmental factors. In this review, we examine the changes that occur in the composition of the gut microbiota across the stages of the HCC and CRC. Based on the idea that the gut microbiota are an additional "lifeline" and contribute to the tumor microenvironment, we can observe from previously published literature how the microbiota can cause a shift in the balance from normal → inflammation → diminished inflammation from early to later disease stages. This pattern leads to the hypothesis that tumor survival depends on a less pro-inflammatory tumor microenvironment. The differences observed in the gut microbiota composition between different disease etiologies as well as between HCC and CRC suggest that the tumor microenvironment is unique for each case.

Gut-Pancreas-Liver Axis as a Target for Treatment of NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) represents the most common form of chronic liver disease worldwide. Due to its association with obesity and diabetes and the fall in hepatitis C virus morbidity, cirrhosis in NAFLD is becoming the most frequent indication to liver transplantation, but the pathogenetic mechanisms are still not completely understood. The so-called gut-liver axis has gained enormous interest when data showed that its alteration can lead to NAFLD development and might favor the occurrence of non-alcoholic steatohepatitis (NASH). Moreover, several therapeutic approaches targeting the gut-pancreas-liver axis, e.g., incretins, showed promising results in NASH treatment. In this review, we describe the role of incretin hormones in NAFLD/NASH pathogenesis and treatment and how metagenomic/metabolomic alterations in the gut microbiota can lead to NASH in the presence of gut barrier modifications favoring the passage of bacteria or bacterial products in the portal circulation, i.e., bacterial translocation.

Opening a Window on Attention: Adjuvant Therapies for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), most commonly known as Crohn's disease (CD) and ulcerative disease (UC), is a chronic and relapsing intestinal disease which cannot be cured completely. The prevalence of IBD in Europe and in North America has increased over the past 20 years. As most IBD patients are young at onset, their quality of life (QOL) can be influenced to varying degrees. Thus, current treatment goals are typically focused on preventing complications, including maintaining clinical remission and improving the QOL. Adjuvant therapies have been widely concerned as an effective treatment in alleviating IBD symptoms, including dietary intervention, traditional Chinese medicine, smoking, alcohol, and physical activities. This review focuses on different ancillary therapies for IBD treatments, in particular the mechanism of reducing inflammation based on the actual data from research studies. Moreover, comparing the latest data, this review also presented potential future prospect for adjuvant therapies.