Exacerbation of alcoholic liver injury by enteral endotoxin in rats

Nutritional and microbiota-based therapeutic interventions for alcohol-associated liver disease: From pathogenesis to therapeutic insights

Alcohol-associated liver disease (ALD) manifests as a consequence of prolonged and excessive alcohol consumption. This disease is closely associated with the interplay between gut health and liver function, which can lead to complex pathophysiological changes in the body. This review offers a comprehensive exploration of ALD's multifaceted nature, with a keen focus on its pathogenesis and the potential of nutritional and microbiota-based therapies. Insights derived from diverse case studies are utilized to shed light on how interventions can rebalance the gut microbiome and enhance liver function in ALD patients. Furthermore, the feasibility of liver transplantation and stem cell therapy as ultimate measures for ALD has been discussed, with acknowledgment of the inherent risks and challenges accompanying them. ALD's complexity underscores the necessity for a thorough understanding of its etiology and progression to devise effective treatments that mitigate its profound impact on an individual's health.

Buddleoside-rich Chrysanthemum indicum L. extract modulates macrophage-mediated inflammation to prevent metabolic syndrome induced by unhealthy diet

BACKGROUND

Metabolic syndrome (MetS) is a precursor to the development of many diseases (atherosclerosis, diabetes, etc.). It is marked by disruptions in glucose and lipid metabolism, along with hypertension. Numerous types of risk factors contribute to the development of the MetS, inflammation and insulin resistance are present throughout the metabolic abnormalities. Chrysanthemum indicum L. is a traditional Chinese plant used for both tea and medicine, known for its high content of total flavonoids, which are important secondary metabolites. Our research led to the extraction of a Buddleoside-Rich Chrysanthemum indicum L. extract (BUDE) which has demonstrated anti-inflammatory properties. Nonetheless, the specific role and mechanism of BUDE in preventing MetS remain unclear.

METHODS

The study initially evaluated the role of BUDE in preventing MetS. Subsequently, it investigated the anti-inflammatory properties of BUDE in the liver and pancreas in response to unhealthy diets. It then examined the level of insulin resistance and pancreatic β-cell function induced by inflammation. Additionally, an lipopolysaccharide (LPS)-induced macrophage inflammation model was used to further investigate the ameliorative effects of BUDE in inflammation.

RESULTS

BUDE has hypotensive, hypoglycemic and hypolipidemic effects. It can also resolve the imbalance between macrophage subpopulations, impede the triggering of the NF-κB signaling pathway, reduce the secretion of inflammatory mediators, ameliorate insulin resistance, and safeguard organs such as the liver and pancreas from inflammatory damage. These effects collectively contribute to preventing the development of MetS.

DISCUSSION

BUDE has the ability to modulate macrophage-mediated inflammation, leading to improved insulin resistance. Additionally, it delivers antihypertensive, hypoglycemic, and hypolipidemic effects, offering a potential for preventing MetS.

Alcohol inducing macrophage M2b polarization in colitis by modulating the TRPV1-MAPK/NF-κB pathways

BACKGROUND

Macrophages exhibit different phenotypes in inflammatory bowel disease (IBD) and promote inflammation or tissue repair depending on their polarization state. Alcohol is a widely used solvent in pharmaceutical formulations, and its consumption is associated with an increased risk of colitis; however, its effects on macrophages in IBD remain poorly understood.

PURPOSE

This study aimed to investigate the effect of alcohol on macrophages in dextran sodium sulfate (DSS)-induced colitis and understand the underlying mechanisms.

METHODS

DSS-treated C57BL/6 mice were exposed to varying concentrations of alcohol, transient receptor potential vanilloid 1 (TRPV1) antagonist, and 5-aminosalicylic acid. The distal colon was resected, fixed, stained, and histologically analyzed, through hematoxylin and eosin (H&E) staining and immunofluorescence staining. Ratio [Ca2+]i measurements, western blotting, quantitative polymerase chain reaction, cytokine measurements, and RNA sequencing analyses were also performed. Peritoneal macrophages and RAW264.7 cells were used for in vitro experiments, and various assays were performed to evaluate cellular responses, gene expression, and signaling pathways.

RESULTS

Alcohol exacerbated DSS-treated mice colitis and promoted the secretion of various inflammatory cytokines from colonic macrophages. Alcohol enhances the calcium ion influx induced by lipopolysaccharide (LPS) in peritoneal macrophages, while the TRPV1 antagonist capsazepine (CPZ) inhibits LPS- and/or alcohol- induced calcium influx in macrophages. Alcohol and LPS activate the MAPK/P38, MAPK/ERK, and NF-κB signaling pathways and induce the macrophage M2b polarization, resulting in the increased expression level of inflammatory cytokines such as Tnf, Il1b, and Il10. Additionally, CPZ can inhibit the facilitatory effects of alcohol or LPS on the abovementioned pathways and inflammatory factors, reversing macrophage M2b polarization and promoting alcohol-induced colitis. The inhibition of nucleotide binding oligomerization domain containing 2 (NOD2) partially suppressed the alcohol and LPS effects on macrophages.

CONCLUSION

Alcohol exacerbates experimental colitis and induces M2b polarization of macrophage via TRPV1-MAPK/NF-κB. Our study provides new insights into the potential therapeutic targets for IBD treatment by elucidating the role of TRPV1 in alcohol-exacerbated colitis, using CPZ as a potential therapeutic option. The identification of transient receptor potential ankyrin subtype 1 (TRPA1) as a therapeutic target expands the scope of future research.

Involvement of the gut microbiome-brain axis in alcohol use disorder

The human intestine is colonized by a variety of microorganisms that influence the immune system, the metabolic response, and the nervous system, with consequences for brain function and behavior. Unbalance in this microbial ecosystem has been shown to be associated with psychiatric disorders, and altered gut microbiome composition related to bacteria, viruses, and fungi has been well established in patients with alcohol use disorder. This review describes the gut microbiome-brain communication pathways, including the ones related to the vagus nerve, the inflammatory cytokines, and the gut-derived metabolites. Finally, the potential benefits of microbiota-based therapies for the management of alcohol use disorder, such as probiotics, prebiotics, and fecal microbiota transplantation, are also discussed.

Porphyromonas gingivalis exacerbates alcoholic liver disease by altering gut microbiota composition and host immune response in mice

AIM

Porphyromonas gingivalis (P. gingivalis), a major periodontal pathogen, increases the risk of systemic diseases. P. gingivalis infection is closely associated with alcoholic liver disease (ALD), but the underlying mechanism remains unclear. We aimed to investigate the role of P. gingivalis in the pathogenesis of ALD.

MATERIALS AND METHODS

An ALD mouse model was established using a Lieber-DeCarli liquid diet, and C57BL/6 mice were treated with P. gingivalis to detect the pathological indicators of ALD.

RESULTS

Oral administration of P. gingivalis exacerbated alcohol-induced alterations in the gut microbiota, leading to gut barrier dysfunction and inflammatory response and disruption of the T-helper 17 cell/T-regulatory cell ratio in the colon of ALD mice. Furthermore, P. gingivalis worsened liver inflammation in ALD mice by increasing the protein expression of toll-like receptor 4 (TLR4) and p65, increasing the mRNA expression of interleukins-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) and up-regulating the transforming growth factor-beta 1 (TGF-β1) and galectin-3 (Gal-3) production.

CONCLUSIONS

These results indicate that P. gingivalis accelerates the pathogenesis of ALD via the oral-gut-liver axis, necessitating a new treatment strategy for patients with ALD complicated by periodontitis.

Pathogenesis of Alcoholic Fatty Liver a Narrative Review

Alcohol effect hepatic lipid metabolism through various mechanisms, leading synergistically to an accumulation of fatty acids (FA) and triglycerides. Obesity, as well as dietary fat (saturated fatty acids (FA) versus poly-unsaturated fatty acids (PUFA)) may modulate the hepatic fat. Alcohol inhibits adenosine monophosphate activated kinase (AMPK). AMPK activates peroxisome proliferator activated receptor a (PPARα) and leads to a decreased activation of sterol regulatory element binding protein 1c (SRABP1c). The inhibition of AMPK, and thus of PPARα, results in an inhibition of FA oxidation. This ß-oxidation is further reduced due to mitochondrial damage induced through cytochrome P4502E1 (CYP2E1)-driven oxidative stress. Furthermore, the synthesis of FAs is stimulated through an activation of SHREP1. In addition, alcohol consumption leads to a reduced production of adiponectin in adipocytes due to oxidative stress and to an increased mobilization of FAs from adipose tissue and from the gut as chylomicrons. On the other side, the secretion of FAs via very-low-density lipoproteins (VLDL) from the liver is inhibited by alcohol. Alcohol also affects signal pathways such as early growth response 1 (Egr-1) associated with the expression of tumour necrosis factor α (TNF α), and the mammalian target of rapamycin (mTOR) a key regulator of autophagy. Both have influence the pathogenesis of alcoholic fatty liver. Alcohol-induced gut dysbiosis contributes to the severity of ALD by increasing the metabolism of ethanol in the gut and promoting intestinal dysfunction. Moreover, pathogen-associated molecular patterns (PAMPS) via specific Toll-like receptor (TLR) bacterial overgrowth leads to the translocation of bacteria. Endotoxins and toxic ethanol metabolites enter the enterohepatic circulation, reaching the liver and inducing the activation of the nuclear factor kappa-B (NFκB) pathway. Pro-inflammatory cytokines released in the process contribute to inflammation and fibrosis. In addition, cellular apoptosis is inhibited in favour of necrosis.

Effect of Prophylactic Antibiotics on Mortality in Severe Alcohol-Related Hepatitis: A Randomized Clinical Trial

Importance

The benefits of prophylactic antibiotics for hospitalized patients with severe alcohol-related hepatitis are unclear.

Objective

To determine the efficacy of amoxicillin-clavulanate, compared with placebo, on mortality in patients hospitalized with severe alcohol-related hepatitis and treated with prednisolone.

Design, Setting, and Participants

Multicenter, randomized, double-blind clinical trial among patients with biopsy-proven severe alcohol-related hepatitis (Maddrey function score ≥32 and Model for End-stage Liver Disease [MELD] score ≥21) from June 13, 2015, to May 24, 2019, in 25 centers in France and Belgium. All patients were followed up for 180 days. Final follow-up occurred on November 19, 2019.

Intervention

Patients were randomly assigned (1:1 allocation) to receive prednisolone combined with amoxicillin-clavulanate (n = 145) or prednisolone combined with placebo (n = 147).

Main Outcome and Measures

The primary outcome was all-cause mortality at 60 days. Secondary outcomes were all-cause mortality at 90 and 180 days; incidence of infection, incidence of hepatorenal syndrome, and proportion of participants with a MELD score less than 17 at 60 days; and proportion of patients with a Lille score less than 0.45 at 7 days.

Results

Among 292 randomized patients (mean age, 52.8 [SD, 9.2] years; 80 [27.4%] women) 284 (97%) were analyzed. There was no significant difference in 60-day mortality between participants randomized to amoxicillin-clavulanate and those randomized to placebo (17.3% in the amoxicillin-clavulanate group and 21.3% in the placebo group [P = .33]; between-group difference, -4.7% [95% CI, -14.0% to 4.7%]; hazard ratio, 0.77 [95% CI, 0.45-1.31]). Infection rates at 60 days were significantly lower in the amoxicillin-clavulanate group (29.7% vs 41.5%; mean difference, -11.8% [95% CI, -23.0% to -0.7%]; subhazard ratio, 0.62; [95% CI, 0.41-0.91]; P = .02). There were no significant differences in any of the remaining 3 secondary outcomes. The most common serious adverse events were related to liver failure (25 in the amoxicillin-clavulanate group and 20 in the placebo group), infections (23 in the amoxicillin-clavulanate group and 46 in the placebo group), and gastrointestinal disorders (15 in the amoxicillin-clavulanate group and 21 in the placebo group).

Conclusion and Relevance

In patients hospitalized with severe alcohol-related hepatitis, amoxicillin-clavulanate combined with prednisolone did not improve 2-month survival compared with prednisolone alone. These results do not support prophylactic antibiotics to improve survival in patients hospitalized with severe alcohol-related hepatitis.

Trial Registration

ClinicalTrials.gov Identifier: NCT02281929.

Lactoferrin, Osteopontin and Lactoferrin–Osteopontin Complex: A Critical Look on Their Role in Perinatal Period and Cardiometabolic Disorders

Milk-derived bioactive proteins have increasingly gained attention and consideration throughout the world due to their high-quality amino acids and multiple health-promoting attributes. Apparently, being at the forefront of functional foods, these bioactive proteins are also suggested as potential alternatives for the management of various complex diseases. In this review, we will focus on lactoferrin (LF) and osteopontin (OPN), two multifunctional dairy proteins, as well as to their naturally occurring bioactive LF–OPN complex. While describing their wide variety of physiological, biochemical, and nutritional functionalities, we will emphasize their specific roles in the perinatal period. Afterwards, we will evaluate their ability to control oxidative stress, inflammation, gut mucosal barrier, and intestinal microbiota in link with cardiometabolic disorders (CMD) (obesity, insulin resistance, dyslipidemia, and hypertension) and associated complications (diabetes and atherosclerosis). This review will not only attempt to highlight the mechanisms of action, but it will critically discuss the potential therapeutic applications of the underlined bioactive proteins in CMD.

Emerging Pharmacotherapies in Alcohol-Associated Hepatitis

The incidence of alcoholic-associated hepatitis (AH) is increasing. The treatment options for severe AH (sAH) are scarce and limited to corticosteroid therapy which showed limited mortality benefit in short-term use only. Therefore, there is a dire need for developing safe and effective therapies for patients with sAH and to improve their high mortality rates.This review article focuses on the current novel therapeutics targeting various mechanisms in the pathogenesis of alcohol-related hepatitis. Anti-inflammatory agents such as IL-1 inhibitor, Pan-caspase inhibitor, Apoptosis signal-regulating kinase-1, and CCL2 inhibitors are under investigation. Other group of agents include gut-liver axis modulators, hepatic regeneration, antioxidants, and Epigenic modulators. We describe the ongoing clinical trials of some of the new agents for alcohol-related hepatitis.

Conclusion

A combination of therapies was investigated, possibly providing a synergistic effect of drugs with different mechanisms. Multiple clinical trials of novel therapies in AH remain ongoing. Their result could potentially make a difference in the clinical course of the disease. DUR-928 and granulocyte colony-stimulating factor had promising results and further trials are ongoing to evaluate their efficacy in the large patient sample.

Therapeutic targets in alcohol-associated liver disease: progress and challenges

Alcohol-associated liver disease (ALD) is a complex disease with rapidly increasing prevalence. Although there are promising therapeutic targets on the horizon, none of the newer targets is currently close to an Food and Drug Administration approval. Strategies are needed to overcome challenges in study designs and conducting clinical trials and provide impetus to the field of drug development in the landscape of ALD and alcoholic hepatitis. Management of ALD is complex and should include therapies to achieve and maintain alcohol abstinence, preferably delivered by a multidisciplinary team. Although associated with clear mortality benefit in select patients, the use of early liver transplantation still requires refinement to create uniformity in selection protocols across transplant centers. There is also a need for reliable noninvasive biomarkers for prognostication. Last but not the least, strategies are urgently needed to implement integrated multidisciplinary care models for treating the dual pathology of alcohol use disorder and of liver disease for improving the long-term outcomes of patients with ALD.

Alcohol use disorder as a potential risk factor for COVID-19 severity: A narrative review

In Dec. 2019-January 2020, a pneumonia illness originating in Wuhan, China, designated as coronavirus disease 2019 (COVID-19) was shown to be caused by a novel RNA coronavirus designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). People with advanced age, male sex, and/or underlying health conditions (obesity, type 2 diabetes, cardiovascular disease, hypertension, chronic kidney disease, and chronic lung disease) are especially vulnerable to severe COVID-19 symptoms and death. These risk factors impact the immune system and are also associated with poor health, chronic illness, and shortened longevity. However, a large percent of patients without these known risk factors also develops severe COVID-19 disease that can result in death. Thus, there must exist risk factors that promote exaggerated inflammatory and immune response to the SARS-CoV-2 virus leading to death. One such risk factor may be alcohol misuse and alcohol use disorder because these can exacerbate viral lung infections like SARS, influenza, and pneumonia. Thus, it is highly plausible that alcohol misuse is a risk factor for either increased infection rate when individuals are exposed to SARS-CoV-2 virus and/or more severe COVID-19 in infected patients. Alcohol use is a well-known risk factor for lung diseases and ARDS in SARS patients. We propose that alcohol has three key pathogenic elements in common with other COVID-19 severity risk factors: namely, inflammatory microbiota dysbiosis, leaky gut, and systemic activation of the NLRP3 inflammasome. We also propose that these three elements represent targets for therapy for severe COVID-19.

Alcohol-Related Liver Disease: An Overview on Pathophysiology, Diagnosis and Therapeutic Perspectives

Alcohol-related liver disease (ALD) refers to a spectrum of liver manifestations ranging from fatty liver diseases, steatohepatitis, and fibrosis/cirrhosis with chronic inflammation primarily due to excessive alcohol use. Currently, ALD is considered as one of the most prevalent causes of liver disease-associated mortality worldwide. Although the pathogenesis of ALD has been intensively investigated, the present understanding of its biomarkers in the context of early clinical diagnosis is not complete, and novel therapeutic targets that can significantly alleviate advanced forms of ALD are limited. While alcohol abstinence remains the primary therapeutic intervention for managing ALD, there are currently no approved medications for treating ALD. Furthermore, given the similarities and the differences between ALD and non-alcoholic fatty liver disease in terms of disease progression and underlying molecular mechanisms, numerous studies have demonstrated that many therapeutic interventions targeting several signaling pathways, including oxidative stress, inflammatory response, hormonal regulation, and hepatocyte death play a significant role in ALD treatment. Therefore, in this review, we summarized several key molecular targets and their modes of action in ALD progression. We also described the updated therapeutic options for ALD management with a particular emphasis on potentially novel signaling pathways.

A Peptide HEPFYGNEGALR from Apostichopus japonicus Alleviates Acute Alcoholic Liver Injury by Enhancing Antioxidant Response in Male C57BL/6J Mice

Liver-related disease caused by alcohol is a frequent disorder of the hepatic tract. Heavy consumption of alcohol in a short period causes oxidative damage to the liver. Sea cucumber is abundant in nutrients and its various extracts have been studied for antioxidant properties. One peptide was isolated and identified from Apostichopus japonicus in our recent study. We investigated the benefits of the peptide in a model of acute ethanol-induced male C57BL/6J mice. Dietary intake of the peptide could attenuate hepatomegaly, hepatitis and the accumulation of lipid droplets, and increase antioxidant enzyme activities in mice with acute alcoholic liver injury. The results indicated that a 20 mg/kg peptide supplement could activate the Nrf2/HO-1 pathway and block the nuclear translocation of NF-κB to alleviate oxidative stress and inflammation. In addition, the preventive effects of peptide supplementation may be related to autophagy. This study suggests that dietary supplementation with a sea cucumber-derived peptide is one of the potential candidates to alleviate acute alcoholic liver injury.

Current Medical Treatment for Alcohol-Associated Liver Disease

Alcohol-associated liver disease is one of the main causes of chronic liver disease. It comprises a clinical-histologic spectrum of presentations, from steatosis, steatohepatitis, to different degrees of fibrosis, including cirrhosis and severe necroinflammatory disease, called alcohol-associated hepatitis. In this focused update, we aim to present specific therapeutic interventions and strategies for the management of alcohol-associated liver disease. Current evidence for management in all spectra of manifestations is derived from general chronic liver disease recommendations, but with a higher emphasis on abstinence and nutritional support. Abstinence should comprise the treatment of alcohol use disorder as well as withdrawal syndrome. Nutritional assessment should also consider the presence of sarcopenia and its clinical manifestation, frailty. The degree of compensation of the disease should be evaluated, and complications, actively sought. The most severe acute form of this disease is alcohol-associated hepatitis, which has high mortality and morbidity. Current treatment is based on corticosteroids that act by reducing immune activation and blocking cytotoxicity and inflammation pathways. Other aspects of treatment include preventing and treating hepatorenal syndrome as well as preventing infections although there is no clear evidence as to the benefit of probiotics and antibiotics in prophylaxis. Novel therapies for alcohol-associated hepatitis include metadoxine, interleukin-22 analogs, and interleukin-1-beta antagonists. Finally, granulocyte colony-stimulating factor, microbiota transplantation, and gut-liver axis modulation have shown promising results. We also discuss palliative care in advanced alcohol-associated liver disease.

Advancements in the Alcohol-Associated Liver Disease Model

Alcohol-associated liver disease (ALD) is an intricate disease that results in a broad spectrum of liver damage. The presentation of ALD can include simple steatosis, steatohepatitis, liver fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC). Effective prevention and treatment strategies are urgently required for ALD patients. In previous decades, numerous rodent models were established to investigate the mechanisms of alcohol-associated liver disease and explore therapeutic targets. This review provides a summary of the latest developments in rodent models, including those that involve EtOH administration, which will help us to understand the characteristics and causes of ALD at different stages. In addition, we discuss the pathogenesis of ALD and summarize the existing in vitro models. We analyse the pros and cons of these models and their translational relevance and summarize the insights that have been gained regarding the mechanisms of alcoholic liver injury.

Beneficial Shifts in Gut Microbiota by Lacticaseibacillus rhamnosus R0011 and Lactobacillus helveticus R0052 in Alcoholic Hepatitis

Gut microbiota performs indispensable functions in the pathophysiology of alcoholic hepatitis (AH). We investigated the effects of Lacticaseibacillus rhamnosus R0011 and Lactobacillus helveticus for gut microbial restoration toward eubiosis in patients with AH. A multicenter, double-blind, and randomized trial was conducted. Probiotics (n = 44) and placebo (n = 45) groups received, during 7 days, L. rhamnosus R0011/L. helveticus R0052 at 120 mg/day and placebo. All patients were hospitalized to ensure abstinence. Liver function, lipopolysaccharide level, and stool analysis were evaluated in patients before and after 7 days of treatment. At baseline, the dominant bacteria were Gram-negative in both groups which decreased after the probiotics treatment and exhibited a significant reduction in lipopolysaccharide level (p < 0.001). The probiotics ameliorated the Child−Pugh scores (p < 0.001). Furthermore, the probiotics group showed a decline in the levels of alanine aminotransferase and gamma-glutamyltranspeptidase (p < 0.05). The probiotics changed the gut microbial composition at various taxonomical levels. The proportion of Bacteroidetes (147%) was increased after 7 days of probiotics supplementation while Proteobacteria (30%) and Fusobacteria (0%) were decreased. Administration of L. rhamnosus R0011 and L. helveticus R0052 conceivably associated with restoration of gut microbiome in AH patients and improved AH by modulating the gut−liver axis.

Crosstalk between Oxidative Stress and Inflammatory Liver Injury in the Pathogenesis of Alcoholic Liver Disease

Alcoholic liver disease (ALD) is characterized by the injury, inflammation, and scarring in the liver owing to excessive alcohol consumption. Currently, ALD is a leading cause for liver transplantation. Therefore, extensive studies (in vitro, in experimental ALD models and in humans) are needed to elucidate pathological features and pathogenic mechanisms underlying ALD. Notably, oxidative changes in the liver have been recognized as a signature trait of ALD. Progression of ALD is linked to the generation of highly reactive free radicals by reactions involving ethanol and its metabolites. Furthermore, hepatic oxidative stress promotes tissue injury and, in turn, stimulates inflammatory responses in the liver, forming a pathological loop that promotes the progression of ALD. Accordingly, accumulating further knowledge on the relationship between oxidative stress and inflammation may help establish a viable therapeutic approach for treating ALD.

Role of Microbiota-Derived Metabolites in Alcoholic and Non-Alcoholic Fatty Liver Diseases

Chronic liver disease encompasses diseases that have various causes, such as alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). Gut microbiota dysregulation plays a key role in the pathogenesis of ALD and NAFLD through the gut-liver axis. The gut microbiota consists of various microorganisms that play a role in maintaining the homeostasis of the host and release a wide number of metabolites, including short-chain fatty acids (SCFAs), peptides, and hormones, continually shaping the host's immunity and metabolism. The integrity of the intestinal mucosal and vascular barriers is crucial to protect liver cells from exposure to harmful metabolites and pathogen-associated molecular pattern molecules. Dysbiosis and increased intestinal permeability may allow the liver to be exposed to abundant harmful metabolites that promote liver inflammation and fibrosis. In this review, we introduce the metabolites and components derived from the gut microbiota and discuss their pathologic effect in the liver alongside recent advances in molecular-based therapeutics and novel mechanistic findings associated with the gut-liver axis in ALD and NAFLD.

Lifestyle and Hepatocellular Carcinoma What Is the Evidence and Prevention Recommendations

Simple Summary

The increasing public health burden of Hepatocellular carcinoma (HCC) emphasizes the importance of defining important modifiable risk factors. In the following review, we will discuss the evidence for the relation of major lifestyle risk factors, mostly from large population-based studies. Generally, it is has been shown that healthy lifestyle habits, including minimizing obesity, eating a healthy diet, avoidance of smoking and alcohol, and increasing physical activity, have the potential to prevent HCC. Dietary composition is important beyond obesity. Consumption of n-3 polyunsaturated fatty acids, as well as fish and poultry, vegetables and fiber, are inversely associated with HCC, while red meat, saturated fat, cholesterol and sugar are related to increased risk. Data from multiple studies clearly show a beneficial effect for physical activity in reducing the risk of HCC. Smoking and alcohol can lead to liver fibrosis and liver cancer and jointly lead to an even greater risk.

Abstract

The increasing burden of hepatocellular carcinoma (HCC) emphasizes the unmet need for primary prevention. Lifestyle measures appear to be important modifiable risk factors for HCC regardless of its etiology. Lifestyle patterns, as a whole and each component separately, are related to HCC risk. Dietary composition is important beyond obesity. Consumption of n-3 polyunsaturated fatty acids, as well as fish and poultry, are inversely associated with HCC, while red meat, saturated fat, and cholesterol are related to increased risk. Sugar consumption is associated with HCC risk, while fiber and vegetable intake is protective. Data from multiple studies clearly show a beneficial effect for physical activity in reducing the risk of HCC. However, the duration, mode and intensity of physical activity needed are yet to be determined. There is evidence that smoking can lead to liver fibrosis and liver cancer and has a synergistic effect with alcohol drinking. On the other hand, an excessive amount of alcohol by itself has been associated with increased risk of HCC directly (carcinogenic effect) or indirectly (liver fibrosis and cirrhosis progression. Large-scale intervention studies testing the effect of comprehensive lifestyle interventions on HCC prevention among diverse cohorts of liver disease patients are greatly warranted.

Selenomethionine-Dominated Selenium-Enriched Peanut Protein Ameliorates Alcohol-Induced Liver Disease in Mice by Suppressing Oxidative Stress

Numerous natural compounds are considered as potential therapeutic agents against alcohol-induced liver disease (ALD). Research shows that selenium (Se) has a variety of bioactivities, including liver protecting ability. The present study based on in vitro cell culture models and in vivo mouse models was aimed at examining the contribution of selenomethionine (SeMet)-dominated Se-enriched peanut protein (SePP) to liver protection. SeMet and especially SePP reversed cell viability and cell death, inhibited ethanol induced CYP2E1 activation, decreased reactive oxygen species level, and restored GSH level. Hence, SeMet-dominated SePP alleviates alcohol-induced AML-12 cytotoxicity by suppressing oxidative stress. The p38-dependent mechanism was found to be responsible for SePP-induced Nrf-2 activation. Furthermore, supplementation with SePP and SeMet regulated lipid metabolism and reduced oxidative stress, minimizing liver damage in mice. Selenomethionine-dominated SePP possesses potential therapeutic properties and can be used to treat ALD through the suppression of oxidative stress.

Combined and sequential effects of alcohol and methamphetamine in animal models

Comorbid drug use, often alcohol with other drugs, poses significant health and societal concerns. Methamphetamine is among the illicit drugs most often co-used with alcohol. The current review examines the animal literature for impacts of comorbid alcohol and methamphetamine exposure. We found evidence for additive or synergistic effects of combined or sequential exposure on behavior and physiology. Dopaminergic, serotonergic, and glutamatergic systems are all impacted by combined exposure to alcohol and methamphetamine and cyclooxygenase-2 activity plays an important role in their combined neurotoxic effects. Adverse consequences of comorbid exposure include altered brain development with prenatal exposure, impaired learning and memory, motor deficits, gastrotoxicity, hepatotoxicity, and augmented intake under some conditions. Given high susceptibility to drug experimentation in adolescence, studies of co-exposure during the adolescent period and of how adolescent exposure to one drug impacts later use or sensitivity to the other drug should be a priority. Further, to gain traction on prevention and treatment, additional research to identify motivational and neurobiological drivers and consequences of comorbid use is needed.

CYP2E1 in Alcoholic and Non-Alcoholic Liver Injury. Roles of ROS, Reactive Intermediates and Lipid Overload

CYP2E1 is one of the fifty-seven cytochrome P450 genes in the human genome and is highly conserved. CYP2E1 is a unique P450 enzyme because its heme iron is constitutively in the high spin state, allowing direct reduction of, e.g., dioxygen, causing the formation of a variety of reactive oxygen species and reduction of xenobiotics to toxic products. The CYP2E1 enzyme has been the focus of scientific interest due to (i) its important endogenous function in liver homeostasis, (ii) its ability to activate procarcinogens and to convert certain drugs, e.g., paracetamol and anesthetics, to cytotoxic end products, (iii) its unique ability to effectively reduce dioxygen to radical species causing liver injury, (iv) its capability to reduce compounds, often generating radical intermediates of direct toxic or indirect immunotoxic properties and (v) its contribution to the development of alcoholic liver disease, steatosis and NASH. In this overview, we present the discovery of the enzyme and studies in humans, 3D liver systems and genetically modified mice to disclose its function and clinical relevance. Induction of the CYP2E1 enzyme either by alcohol or high-fat diet leads to increased severity of liver pathology and likelihood to develop ALD and NASH, with subsequent influence on the occurrence of hepatocellular cancer. Thus, fat-dependent induction of the enzyme might provide a link between steatosis and fibrosis in the liver. We conclude that CYP2E1 has many important physiological functions and is a key enzyme for hepatic carcinogenesis, drug toxicity and liver disease.

Gut inflammation exacerbates hepatic injury in C57BL/6J mice via gut-vascular barrier dysfunction with high-fat-incorporated meat protein diets

AIM

Meat and its derivatives provide nutrients essential for human health. However, meat consumption, along with excessive fat intake, has been associated with gut inflammation, intestinal barrier dysfunction and alterations in gut microbiota. Herein, we investigated whether and how these changes in the intestinal barrier system affect the gut liver axis and hepatic injury and eventually lead to the progression of liver syndrome such as NAFLD.

METHODS

Mice were fed with high fat (60% kcal) or low fat (12% kcal) along with soybean (control), chicken and pork proteins (HFCH, HFP, LFCH, and LFP) for 12 weeks. The biomarkers for liver injury were investigated after meat protein intake along with the high fat.

FINDINGS

Greater amount of fat vacuoles visible in the H&E staining increased the inflammatory cell infiltration and disorganized liver structures were observed in the HFP-fed mice. Oil Red O staining revealed that the HFP-fed and HFCH-fed mice showed more lipid droplets, confirming the increased hepatic lipid accumulation. Potential serum markers for NAFLD, ALT and AST were increased in the HF meat diet groups. Key genes responsible for hepatic inflammation and lipogenesis, such as MCP-1, IL1-β and TNF-α were upregulated. HF meat protein diet-fed mice exhibited signs of compromised liver with increased levels of endotoxin in the liver and its binding protein in serum, upregulation of TLRs in the liver, and significant increase in TG, TC, LDL-C and HDL-C concentrations.

SIGNIFICANCE

Intestinal inflammation and barrier dysfunction aggravate liver injury and fibrosis due to the intake of HF meat protein diets in mice, which may contribute to the progress of liver injury and associated complications. Gut inflammation may directly contribute to the development of NAFLD, especially of the gut vascular barricade dysfunction.

Microbiota tryptophan metabolism induces aryl hydrocarbon receptor activation and improves alcohol-induced liver injury

OBJECTIVE

Chronic alcohol consumption is an important cause of liver-related deaths. Specific intestinal microbiota profiles are associated with susceptibility or resistance to alcoholic liver disease in both mice and humans. We aimed to identify the mechanisms by which targeting intestinal microbiota can improve alcohol-induced liver lesions.

DESIGN

We used human associated mice, a mouse model of alcoholic liver disease transplanted with the intestinal microbiota of alcoholic patients and used the prebiotic, pectin, to modulate the intestinal microbiota. Based on metabolomic analyses, we focused on microbiota tryptophan metabolites, which are ligands of the aryl hydrocarbon receptor (AhR). Involvement of the AhR pathway was assessed using both a pharmacological approach and AhR-deficient mice.

RESULTS

Pectin treatment modified the microbiome and metabolome in human microbiota-associated alcohol-fed mice, leading to a specific faecal signature. High production of bacterial tryptophan metabolites was associated with an improvement of liver injury. The AhR agonist Ficz (6-formylindolo (3,2-b) carbazole) reduced liver lesions, similarly to prebiotic treatment. Conversely, inactivation of the ahr gene in alcohol-fed AhR knock-out mice abrogated the beneficial effects of the prebiotic. Importantly, patients with severe alcoholic hepatitis have low levels of bacterial tryptophan derivatives that are AhR agonists.

CONCLUSIONS

Improvement of alcoholic liver disease by targeting the intestinal microbiota involves the AhR pathway, which should be considered as a new therapeutic target.

Metformin and Probiotics Interplay in Amelioration of Ethanol-Induced Oxidative Stress and Inflammatory Response in an In Vitro and In Vivo Model of Hepatic Injury

Alcohol-induced liver injury implicates inflammation and oxidative stress as important mediators. Despite rigorous research, there is still no Food and Drug Administration (FDA) approved therapies for any stage of alcoholic liver disease (ALD). Interestingly, metformin (Met) and several probiotic strains possess the potential of inhibiting alcoholic liver injury. Therefore, we investigated the effectiveness of combination therapy using a mixture of eight strains of lactic acid-producing bacteria, commercialized as Visbiome® (V) and Met in preventing the ethanol-induced hepatic injury using in vitro and in vivo models. Human HepG2 cells and male Wistar rats were exposed to ethanol and simultaneously treated with probiotic V or Met alone as well as in combination. Endoplasmic reticulum (ER) stress markers, inflammatory markers, lipid metabolism, reactive oxygen species (ROS) production, and oxidative stress were evaluated, using qRT-PCR, Oil red O staining, fluorimetry, and HPLC. In vitro, probiotic V and Met in combination prevented ethanol-induced cellular injury, ER stress, oxidative stress, and regulated lipid metabolism as well as inflammatory response in HepG2 cells. Probiotic V and Met also promoted macrophage polarization towards the M2 phenotype in ethanol-exposed RAW 264.7 macrophage cells. In vivo, combined administration of probiotic V and Met ameliorated the histopathological changes, inflammatory response, hepatic markers (liver enzymes), and lipid metabolism induced by ethanol. It also improved the antioxidant markers (HO-1 and Nrf-2), as seen by their protein levels in both HepG2 cells as well as liver tissue using ELISA. Hence, probiotic V may act, in addition to the Met, as an effective preventive treatment against ethanol-induced hepatic injury.

Alpha-1 antitrypsin governs alcohol-related liver disease in mice and humans

OBJECTIVE

Alcohol-related liver disease (ALD) is a global healthcare problem with limited treatment options. Alpha-1 antitrypsin (AAT, encoded by SERPINA1) shows potent anti-inflammatory activities in many preclinical and clinical trials. In our study, we aimed to explore the role of AAT in ALD.

DESIGN

An unselected cohort of 512 patients with cirrhosis was clinically characterised. Survival, clinical and biochemical parameters including AAT serum concentration were compared between patients with ALD and other aetiologies of liver disease. The role of AAT was evaluated in experimental ALD models.

RESULTS

Cirrhotic ALD patients with AAT serum concentrations less than 120 mg/dL had a significantly higher risk for death/liver transplantation as compared with patients with AAT serum concentrations higher than 120 mg/dL. Multivariate Cox regression analysis showed that low AAT serum concentration was a NaMELD-independent predictor of survival/transplantation. Ethanol-fed wild-type (wt) mice displayed a significant decline in hepatic AAT compared with pair-fed mice. Therefore, hAAT-Tg mice were ethanol-fed, and these mice displayed protection from liver injury associated with decreased steatosis, hepatic neutrophil infiltration and abated expression of proinflammatory cytokines. To test the therapeutic capability of AAT, ethanol-fed wt mice were treated with human AAT. Administration of AAT ameliorated hepatic injury, neutrophil infiltration and steatosis.

CONCLUSION

Cirrhotic ALD patients with AAT concentrations less than 120 mg/dL displayed an increased risk for death/liver transplantation. Both hAAT-Tg mice and AAT-treated wt animals showed protection from ethanol-induced liver injury. AAT could reflect a treatment option for human ALD, especially for alcoholic hepatitis.

Modulation of the TLR4/MyD88/NF-κB Pathway by Humulus japonicus Extract Protects Against Alcohol-Induced Liver Injury in a Rat Model

Alcohol induces liver injury related to oxidative stress and inflammatory responses. The purpose of this study was to investigate the hepatoprotective effect of Humulus japonicus extract (HJE) against alcohol-induced liver injury. Furthermore, we investigated the mechanisms of the protective effect of HJE on alcohol-induced liver injury. The pretreatment of HJE decreased the levels of aspartate aminotransferase, alanine aminotransferase, triglyceride, and total cholesterol in the plasma, suppressed the malondialdehyde, myeloperoxidase, and enhanced the activities of superoxide dismutase, glutathione, and catalase. The inhibitory effect of HJE against oxidative stress may be associated with the upregulation of nuclear factor erythroid 2-related factor 2 and its target gene heme oxygenase-1. Moreover, HJE inhibited the pro-inflammatory cytokines (tumor necrosis factor alpha, interleukin-1 beta) by downregulating toll-like receptor 4, myeloid differentiation primary response 88, and nuclear factor kappa B p65. These findings provide evidence for the elucidation of the hepatoprotective mechanisms for HJE.

Oxidation of fish oil exacerbates alcoholic liver disease by enhancing intestinal dysbiosis in mice

The role of n-3 polyunsaturated fatty acids (PUFAs) in alcoholic liver disease (ALD) has been controversial. N-3 PUFA oxidation in animal feeding stuffs was rarely concerned, likely contributing to inconsistent outcomes. Here, we report the impacts of oxidized fish oil (OFO) on ALD in C57BL/6 mice. Alcohol exposure increased plasma aminotransferase levels and hepatic inflammation. These deleterious effects were ameliorated by unoxidized FO but exacerbated by OFO. Sequencing analysis showed the accentuated intestinal dysbiosis and the increased proportion of Proteobacteria in OFO-fed mice. Intestinal sterilization by antibiotics completely abolished OFO-aggravated liver injury. Additionally, alcohol exposure leads to the greater increase in plasma endotoxin and decrease in intestinal tight junction protein expressions in OFO-fed mice. Stabilization of intestinal barrier by obeticholic acid markedly blunted OFO-aggravated liver injury in alcohol-fed mice. These results demonstrate that OFO exacerbates alcoholic liver injury through enhancing intestinal dysbiosis, barrier dysfunction, and hepatic inflammation mediated by gut-derived endotoxin.

Feng et al. show that oxidized fish oil exacerbates alcoholic liver injury in mice by enhancing intestinal dysbiosis, barrier dysfunction, and hepatic inflammation that is mediated by gut-derived endotoxin. This study suggests that n-3 polyunsaturated fatty acids enriched in fish oil should be kept from oxidation to exert their health benefits.

Serum immunoglobulin A levels and alcohol-induced liver disease

Background: Recent data suggest intestinal immunity including immunoglobulin A (IgA) may contribute to the pathogenesis of alcohol-induced liver disease (ALD). Methods: We documented serum IgA levels in ALD patients and determined whether those with elevated levels of IgA (E-IgA) had similar, more, or less advanced disease and different rates of progression than those with normal levels of IgA (N-IgA). Standard liver function tests (bilirubin, international normalized ratio [INR], and albumin), model for end-stage liver disease (MELD), and Fibrosis-4 (FIB-4) scores were used as indicators of disease severity. Results: From the study centre’s clinical database, we identified 175 adult patients with ALD, 107 (61%) with E-IgA and 68 (39%) with N-IgA. Gender distribution and mean age of the two cohorts were similar. E-IgA patients had biochemical evidence of more advanced liver disease (higher serum bilirubin and INR and lower albumin levels) than N-IgA patients ( ps < .05). E-IgA patients also had significantly higher median MELD and FIB-4 scores ( ps < .01). A higher percentage of E-IgA patients had FIB-4 values in keeping with advanced fibrosis or cirrhosis (55% versus 28%, p = .02). After mean follow-up periods of approximately 4 years, liver biochemistry and MELD and FIB-4 scores changed to similar extents in the two cohorts. Conclusions: Serum IgA levels were increased in approximately 70% of ALD patients. Although these patients had biochemical and non-invasive indicators of more advanced disease, elevations in serum IgA levels do not predict disease progression; therefore, IgA is unlikely to be of importance in the pathogenesis of ALD.

Combined alcoholic and non-alcoholic steatohepatitis

While metabolic syndrome and alcohol consumption are the two main causes of chronic liver disease, one of the two conditions is often predominant, with the other acting as a cofactor of morbimortality. It has been shown that obesity and alcohol act synergistically to increase the risk of fibrosis progression, hepatic carcinogenesis and mortality, while genetic polymorphisms can strongly influence disease progression. Based on common pathogenic pathways, there are several potential targets that could be used to treat both diseases; based on the prevalence and incidence of these diseases, new therapies and clinical trials are needed urgently.

Allicin Modifies the Composition and Function of the Gut Microbiota in Alcoholic Hepatic Steatosis Mice

The intestinal microbiome plays an important role in the pathogenesis of liver diseases. Alcohol intake induces gut microbiota dysbiosis and alters its function. This study investigated the antibiotic effect of allicin in mice with hepatic steatosis. Male C57BL/6 mice were administered an ethanol diet supplemented with allicin (5 and 20 mg/(kg bw day)) for 4 weeks. Allicin modified the gut microbiota composition. Cecal microbiota exhibited a positive correlation with alcohol and hepatic triacylglycerol, but were suppressed with allicin. Ethanol diet with 5 mg of allicin induced a lower intestinal permeability compared to the ethanol diet alone. Allicin mediated the lipopolysaccharide (LPS)-CD14-toll-like receptor 4 (TLR4)-induced hepatic inflammation pathway by reducing LPS, CD14, TLR4, and pro-inflammatory cytokines-tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. However, hepatic inflammation primarily resulted from alcohol toxicity rather than LPS production in the gut. The prediction of functional profiles from metagenomic 16S ribosomal RNA (rRNA) data revealed different functional profiles in each group. The predicted aldehyde dehydrogenase tended to increase in alcoholic mice administered allicin. The predicted LPS-related pathway and LPS biosynthesis protein results exhibited a similar trend as plasma LPS levels. Thus, alcohol and allicin intake shapes the gut microbiota and its functional profile and improves the CD14-TLR4 pathway to alleviate inflammation in the liver.

Role of gut microbiota in liver disease

The gut microbiome is the natural intestinal inhabitant that has been recognized recently as a major player in the maintenance of human health and the pathophysiology of many diseases. Those commensals produce metabolites that have various effects on host biological functions. Therefore, alterations in the normal composition or diversity of microbiome have been implicated in various diseases, including liver cirrhosis and nonalcoholic fatty liver disease. Moreover, accumulating evidence suggests that progression of dysbiosis can be associated with worsening of liver disease. Here, we review the possible roles for gut microbiota in the development, progression, and complication of liver disease.

Lactobacillus rhamnosus Granules Dose-Dependently Balance Intestinal Microbiome Disorders and Ameliorate Chronic Alcohol-Induced Liver Injury

As the functions of Lactobacilli become better understood, there are increasing numbers of applications for Lactobacillus products. Previously, we have demonstrated that Lactobacillus rhamnosus GG (LGG) can prevent alcoholic liver injury. LGG granules were produced by fluid bed granulation with a media composed of starch, skimmed milk powder, whey powder, microcrystalline cellulose and maltose, and LGG fermented liquid that comprised 30-50% of the total weight. We found LGG granules dose-dependently protected against chronic alcoholic liver disease. When alcohol was consumed for 8 weeks with LGG treatment during the last 2 weeks, we demonstrated that the dose dependence of LGG granules can improve alcohol-induced liver injury through decreasing the levels of lipopolysaccharide and tumor necrosis factor-α in serum and prevent liver steatosis by suppressing triglyceride, free fatty acid, and malondialdehyde production in liver. Alcohol feeding caused a decline in the number of both Lactobacillus and Bifidobacterium, with a proportional increase in the number of Clostridium perfringens in ileum, and expansion of the Gram-negative bacteria Proteobacteria, Campylobacterales, and Helicobacter in cecum. However, LGG granule treatment restored the content of these microorganisms. In conclusion, LGG granule supplementation can improve the intestinal microbiota, reduce the number of gram-negative bacteria, and ameliorate alcoholic liver injury.

Natural compounds in the chemoprevention of alcoholic liver disease

Alcoholic liver disease (ALD), caused by excessive consumption of alcohol, is a major cause of chronic liver disease worldwide. Much effort has been expended to explore the pathogenesis of ALD. Hepatic cell injury, oxidative stress, inflammation, regeneration, and bacterial translocation are all involved in the pathogenesis of ALD. Immediate abstinence is the most important therapeutic treatment for affected individuals. However, the medical treatment for ALD had not advanced in a long period. Intriguingly, an increasing body of research indicates the potential of natural compounds in the targeted therapy of ALD. A plethora of dietary natural products such as flavonoids, resveratrol, saponins, and β-carotene are found to exert protective effects on ALD. This occurs through various mechanisms composed of antioxidative, anti-inflammatory, iron chelation, pro-apoptosis, and/or antiproliferation of hepatic stellate cells and hepatocellular carcinoma cells. In this review, we will summarize current knowledge about the pathogenesis and treatments of ALD and focus on the potential of natural compounds in ALD therapies and underlying mechanisms.

Value of gadoxetic acid-enhanced MRI and diffusion-weighted imaging in the differentiation of hypervascular hyperplastic nodule from small (<3 cm) hypervascular hepatocellular carcinoma in patients with alcoholic liver cirrhosis: A retrospective case-control study

BACKGROUND

Hypervascular hyperplastic nodules (HHNs) occasionally develop in patients with alcoholic liver cirrhosis (ALC) and show arterial enhancement, thus mimicking hepatocellular carcinoma (HCC). Importantly, HHN as a benign lesion should be distinguished from HCC.

PURPOSE

To evaluate the value of gadoxetic acid-enhanced MRI (Gd-EOB-MRI) and diffusion-weighted imaging (DWI) in distinguishing HHN from small (<3 cm) hypervascular HCC (hHCC) in patients with ALC.

STUDY TYPE

Retrospective case-control study.

FIELD STRENGTH/SEQUENCE

3.0T/in- and out-of-phase, T₁ -weighted, T₂ -weighted, diffusion-weighted, apparent diffusion coefficient, and dynamic gadoxetic acid-enhanced images.

POPULATION

Among 560 patients with ALC who underwent Gd-EOB-MRI and DWI, 12 patients with 28 HHNs and 22 patients with 29 hHCCs smaller than 3 cm were included.

ASSESSMENT

The following MRI features were evaluated by three independent radiologists: signal intensity (SI) on T₁ -weighted, T₂ -weighted, diffusion-weighted, and hepatobiliary phase (HBP) images; shape, homogeneity, and margin on HBP; diffusion restriction; intralesional fat; necrosis; hemorrhage; washout on portal venous phase (PVP) and/or transitional phase (TP); and capsular enhancement. Quantitative analysis was also conducted.

STATISTICAL TESTS

Univariate and multivariate analyses were performed to determine the significant MRI findings, and their diagnostic performance for the prediction of HHN was analyzed.

RESULTS

Lesion size of ≤16 mm (odds ratio [OR], 24.41; P = 0.007), low-to-iso SI on DWI (OR, 26.92; P = 0.007), and absence of washout on PVP and/or TP (OR, 31.84; P = 0.009) were significant independent factors for predicting HHN. When all three criteria were satisfied, the specificity was 100%. Compared with hHCCs, HHNs showed significantly smaller size (mean, 13.8 mm vs. 19.9 mm; P < 0.001) and higher mean SI value (994.0 vs. 669.5) and lesion-to-liver SI ratio (1.045 vs. 0.806) on HBP (P < 0.001, respectively).

DATA CONCLUSION

Gd-EOB-MRI and DWI may be helpful in differentiating HHN from small hHCC in patients with ALC.

LEVEL OF EVIDENCE

3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:70-80.

Alcohol and hepatocellular carcinoma

BACKGROUND

Alcohol is classified as a Group 1 carcinogen by the International Agency for Research on Cancer because it induces hepatocellular carcinoma (among other cancers) in humans. An excessive alcohol intake may result in fatty liver, acute/chronic hepatitis, and cirrhosis and eventually lead to hepatocellular carcinoma. It has been reported that alcohol abuse increases the relative risk of hepatocellular carcinoma by 3- to 10-fold.

AIM AND METHODS

To clarify the known mechanisms of alcohol-related carcinogenesis, we searched Pubmed using the terms alcohol and immune mechanism, alcohol and cancer, and immune mechanism and cancer and summarized the articles as a qualitative review.

RESULTS

From a clinical perspective, it is well known that alcohol interacts with other factors, such as smoking, viral hepatitis, and diabetes, leading to an increased risk of hepatocellular carcinoma. There are several possible mechanisms through which alcohol may induce liver carcinogenicity, including the mutagenic effects of acetaldehyde and the production of ROS due to the excessive hepatic deposition of iron. Furthermore, it has been reported that alcohol accelerates hepatitis C virus-induced liver tumorigenesis through TLR4 signaling. Despite intense investigations to elucidate the mechanisms, they remain poorly understood.

CONCLUSION

This review summarizes the recent findings of clinical and pathological studies that have investigated the carcinogenic effects of alcohol in the liver.

Circulating levels of 3-hydroxymyristate, a direct quantification of endotoxaemia in noninfected cirrhotic patients

BACKGROUND & AIMS

The quantification of lipopolysaccharide (LPS) in biological fluids is challenging. We aimed to measure plasma LPS concentration using a new method of direct quantification of 3-hydroxymyristate (3-HM), a lipid component of LPS, and to evaluate correlations between 3-HM and markers of liver function, endothelial activation, portal hypertension and enterocyte damage.

METHODS

Plasma from 90 noninfected cirrhotic patients (30 Child-Pugh [CP]-A, 30 CP-B, 30 CP-C) was prospectively collected. The concentration of 3-HM was determined by high-performance liquid chromatography coupled with mass spectrometry.

RESULTS

3-HM levels were higher in CP-C patients (CP-A/CP-B/CP-C: 68/70/103 ng/mL, P = 0.005). Patients with severe acute alcoholic hepatitis (n = 16; 113 vs 74 ng/mL, P = 0.012), diabetic patients (n = 22; 99 vs 70 ng/mL, P = 0.028) and those not receiving beta blockers (n = 44; 98 vs 72 ng/mL, P = 0.034) had higher levels of 3-HM. We observed a trend towards higher baseline levels of 3-HM in patients with hepatic encephalopathy (n = 7; 144 vs 76 ng/mL, P = 0.45) or SIRS (n = 10; 106 vs 75 ng/mL, P = 0.114). In multivariate analysis, high levels of 3-HM were associated with CP (OR = 4.39; 95%CI = 1.79-10.76) or MELD (OR = 8.24; 95%CI = 3.19-21.32) scores. Patients dying from liver insufficiency (n = 6) during a 12-month follow-up had higher baseline levels of 3-HM (106 vs 75 ng/mL, P = 0.089).

CONCLUSIONS

In noninfected cirrhotic patients, 3-HM arises more frequently with impairment of liver function, heavy alcohol consumption, diabetic status, nonuse of beta blockers and a trend towards poorer outcome is also observed. The direct mass measurement of LPS using 3-HM appears reliable to detect transient endotoxaemia and promising to manage the follow-up of cirrhotic patients.

Deletion of TLR-4 attenuates fetal alcohol exposure-induced gene expression and social interaction deficits

Fetal alcohol spectrum disorders (FASD) are associated with social interaction behavior and gastrointestinal (GI) abnormalities. These abnormal behaviors and GI abnormalities overlap with autism spectrum disorder (ASD). We investigated the effect of fetal alcohol exposure (FAE) on social interaction deficits (hallmark of autism) in mice. Evidence indicates that exogenous lipopolysaccharide (LPS) administration during gestation induces autism-like behavior in the offspring. LPS regulates the expression of genes underlying differentiation, immune function, myelination, and synaptogenesis in fetal brain by the LPS receptor, TLR-4-dependent mechanism. In this study, we evaluated the role of TLR-4 in FAE-induced social behavior deficit. WT and TLR4^-/- pregnant mice were fed Lieber-DeCarli liquid diet with or without ethanol. The control group was pair-fed with an isocaloric diet. Social behavior was tested in the adult offspring at postnatal day 60. Frontal cortex mRNA expression of autistic candidate genes (Ube3a, Gabrb3, Mecp2) and inflammatory cytokine genes (IL-1β, IL-6, TNF-α) were measured by RT-qPCR. Adult male offspring of ethanol-fed WT dams showed low birth weight compared to offspring of pair-fed WT dams. However, their body weights at adulthood were greater compared to the body weights of offspring of pair-fed WT dams. There were no body weight differences in offspring of TLR4^-/- dams. Social interaction deficit was observed only in male offspring of ethanol-fed WT dams, but it was not observed in both male and female offspring of ethanol-fed TLR4^-/- dams. Expressions of autism candidate genes, Gabrb3 and Ube3a, were elevated, while that of the Mecp2 gene was suppressed in the frontal cortex of male, but not female, offspring of ethanol-fed WT mice. The expressions of inflammatory cytokine genes, IL-1β, IL-6, and TNF-α, were also significantly increased in the frontal cortex of male, but not female, offspring of ethanol-fed dams. The changes in the expression of autistic and cytokine genes were unaffected in the offspring of ethanol-fed TLR4^-/- dams. These data also indicate that TLR4 mediates FAE-induced changes in social interactions and gene expression in brain, suggesting that ethanol-induced LPS absorption from the maternal gut may be involved in gene expression changes in the fetal brain.

Alcoholic liver disease: A current molecular and clinical perspective

Heavy alcohol use is the cause of alcoholic liver disease (ALD). The ALD spectrum ranges from alcoholic steatosis to steatohepatitis, fibrosis, and cirrhosis. In Western countries, approximately 50% of cirrhosis-related deaths are due to alcohol use. While alcoholic cirrhosis is no longer considered a completely irreversible condition, no effective anti-fibrotic therapies are currently available. Another significant clinical aspect of ALD is alcoholic hepatitis (AH). AH is an acute inflammatory condition that is often comorbid with cirrhosis, and severe AH has a high mortality rate. Therapeutic options for ALD are limited. The established treatment for AH is corticosteroids, which improve short-term survival but do not affect long-term survival. Liver transplantation is a curative treatment option for alcoholic cirrhosis and AH, but patients must abstain from alcohol use for 6 months to qualify. Additional effective therapies are needed. The molecular mechanisms underlying ALD are complex and have not been fully elucidated. Various molecules, signaling pathways, and crosstalk between multiple hepatic and extrahepatic cells contribute to ALD progression. This review highlights established and emerging concepts in ALD clinicopathology, their underlying molecular mechanisms, and current and future ALD treatment options.

Bile acid homeostasis and intestinal dysbiosis in alcoholic hepatitis

BACKGROUND

Intestinal microbiota plays an important role in bile acid homeostasis.

AIM

To study the structure of the intestinal microbiota and its function in bile acid homeostasis in alcoholic patients based on the severity of alcoholic liver disease.

METHODS

In this prospective study, we included four groups of active alcoholic patients (N = 108): two noncirrhotic, with (noCir_AH, n = 13) or without alcoholic hepatitis (noCir_noAH, n = 61), and two cirrhotic, with (Cir_sAH, n = 17) or without severe alcoholic hepatitis (Cir_noAH, n = 17). Plasma and faecal bile acid profiles and intestinal microbiota composition were assessed.

RESULTS

Plasma levels of total bile acids (84.6 vs 6.8 μmol/L, P < 0.001) and total ursodeoxycholic acid (1.3 vs 0.3 μmol/L, P = 0.03) were higher in cirrhosis with severe alcoholic hepatitis (Cir_sAH) than Cir_noAH, whereas total faecal (2.4 vs 11.3, P = 0.01) and secondary bile acids (0.7 vs 10.7, P < 0.01) levels were lower. Cir_sAH patients had a different microbiota than Cir_noAH patients: at the phyla level, the abundance of Actinobacteria (9 vs 1%, P = 0.01) was higher and that of Bacteroidetes was lower (25 vs 40%, P = 0.04). Moreover, the microbiota of Cir_sAH patients showed changes in the abundance of genes involved in 15 metabolic pathways, including upregulation of glutathione metabolism, and downregulation of biotin metabolism.

CONCLUSIONS

Patients with Cir_sAH show specific changes of the bile acid pool with a shift towards more hydrophobic and toxic species that may be responsible for the specific microbiota changes. Conversely, the microbiota may also alter the bile acid pool by transforming primary to secondary bile acids, leading to a vicious cycle.

Hépatite alcoolique aiguë sévère

Tout patient consommateur chronique et excessif d’alcool avec un ictère récent doit être évalué par le score de Maddrey à la recherche d’une hépatite alcoolique aiguë sévère. Les corticostéroïdes représentent le traitement de première ligne, associés à un soutien nutritionnel adapté et à une abstinence alcoolique. La combinaison corticostéroïdes plus N-acétylcystéine (perfusée pendant les cinq premiers jours) améliore la survie à court terme par rapport aux corticostéroïdes seuls, constituant une option thérapeutique de première ligne. La réponse au traitement est évaluée au septième jour par le modèle de Lille inférieur ou égal à 0,45. Le pronostic des patients non répondeurs aux corticostéroïdes avec un modèle de Lille supérieur à 0,45 est sombre avec une survie de 23 % à six mois. Pour des patients non répondeurs aux corticostéroïdes et sélectionnés, la transplantation hépatique précoce améliore significativement la survie à six mois et à long terme.

Gut inflammation exacerbates hepatic injury in the high-fat diet induced NAFLD mouse: Attention to the gut-vascular barrier dysfunction

AIMS

Gut inflammation has been put forward to be associated with hepatic injury in the clinical practice. The dismantled intestinal barrier was highly concerned, however, largely unknown about the role of gut-vascular barrier (GVB) in this process. This study aimed to investigate if inflamed gut directly contributes to the progression of non-alcoholic steatohepatitis (NASH), especially attention to the GVB dysfunction.

MAIN METHODS

Male C57bl/6 mice were fed with a high-fat diet (HFD) and 1% DSS for 12 weeks. The colonic inflammatory injury as well as hepatic injury were evaluated. The GVB function was assessed via measuring the permeability to fluorescently-labeled dextran (70 kDa) and the expression of plasmalemma vesicle-associated protein-1 (PV1). Furthermore, the plasma endotoxin level and hepatic TLR4/TLR9 mRNA expression were detected.

KEY FINDINGS

There were evident colitis in DSS-exposed mice, which trend to be more apparent in HFD ones. The HFD + DSS mice exhibited more serious hepatic steatosis, inflammation and fibrosis than HFD groups. The downregulated tight junction protein in HFD + DSS mice indicated loss of epithelial barrier. The GVB disruption were also confirmed with increased permeability to macromolecules and high expression of endothelial PV1 in HFD + DSS mice. Accordingly, potentially elevated plasma endotoxin levels and markedly increased TLR4/TLR9 mRNA expression were demonstrated in HFD + DSS mice rather than HFD groups.

SIGNIFICANCE

Gut inflammation exacerbates liver injury and fibrosis in HFD mice, which may contribute to the development of NASH. Beyond the damaged intestinal epithelial barrier, GVB disruption with bacterial translocation into may play a key role in the pathogenesis of NASH.

Shanxi Aged Vinegar Protects against Alcohol-Induced Liver Injury via Activating Nrf2-Mediated Antioxidant and Inhibiting TLR4-Induced Inflammatory Response

Shanxi aged vinegar (SAV) is a typical fermented and antioxidant food, which has various health-promoting effects. This work aimed to explore the effects of SAV on alcohol-induced liver injury. A mice model of alcoholic liver injury was established to illuminate its potential mechanisms. All mice pretreated with SAV and then received an ethanol solution (50% w/v, 4.8 g/kg b.w.). The results showed that SAV ameliorated alcohol-induced histological changes and elevation of liver enzymes. SAV attenuated alcohol-induced oxidative stress by declining levels of hepatic oxidants, and restoring depletion of antioxidant enzyme activities in mice livers. Moreover, SAV alleviated alcohol-induced oxidative damage by activating nuclear factor erythroid-2-related factor 2 (Nrf2)-mediated signal pathway. In addition, SAV prevented alcohol-induced inflammation by suppressing lipopolysaccharide (LPS) level and activities of pro-inflammatory enzymes, and regulating inflammatory cytokines. SAV inhibited alcohol-induced inflammation through down-regulating the expression of Toll-like receptor 4 (TLR4)-mediated inflammatory response. The findings provide crucial evidence for elucidating the hepatoprotective mechanisms of SAV and encourage the future application of SAV as a functional food for liver protection.

Microbiota, a key player in alcoholic liver disease

Alcoholic liver disease (ALD) is a major cause of morbidity and mortality worldwide. Only 20% of heavy alcohol consumers develop alcoholic liver cirrhosis. The intestinal microbiota (IM) has been recently identified as a key player in the severity of liver injury in ALD. Common features of ALD include a decrease of gut epithelial tight junction protein expression, mucin production, and antimicrobial peptide levels. This disruption of the gut barrier, which is a prerequisite for ALD, leads to the passage of bacterial products into the blood stream (endotoxemia). Moreover, metabolites produced by bacteria, such as short chain fatty acids, volatile organic compounds (VOS), and bile acids (BA), are involved in ALD pathology. Probiotic treatment, IM transplantation, or the consumption of dietary fiber, such as pectin, which all alter the ratio of bacterial species, have been shown to improve liver injury in animal models of ALD and to be associated with an improvement in gut barrier function. Although the connections between the microbiota and the host in ALD are well established, the underlying mechanisms are still an active area of research. Targeting the microbiome through the use of prebiotic, probiotic, and postbiotic modalities could be an attractive new approach to manage ALD.

"Immune Gate" of Psychopathology-The Role of Gut Derived Immune Activation in Major Psychiatric Disorders

Interaction between the gastrointestinal tract (GI) and brain functions has recently become a topic of growing interest in psychiatric research. These multidirectional interactions take place in the so-called gut-brain axis or more precisely, the microbiota-gut-brain axis. The GI tract is the largest immune organ in the human body and is also the largest surface of contact with the external environment. Its functions and permeability are highly influenced by psychological stress, which are often a precipitating factor in the first episode, reoccurrence and/or deterioration of symptoms of psychiatric disorders. In recent literature there is growing evidence that increased intestinal permeability with subsequent immune activation has a major role in the pathophysiology of various psychiatric disorders. Numerous parameters measured in this context seem to be aftermaths of those mechanisms, yet at the same time they may be contributing factors for immune mediated psychopathology. For example, immune activation related to gut-derived bacterial lipopolysaccharides (LPS) or various food antigens and exorphins were reported in major depression, schizophrenia, bipolar disorder, alcoholism and autism. In this review the authors will summarize the evidence and roles of such parameters and their assessment in major psychiatric disorders.