Endotoxemia and gut barrier dysfunction in alcoholic liver disease

Fulminant necrotizing fasciitis by Edwardsiella tarda in a patient with alcoholic liver cirrhosis: A case report

We herein present a unique and extremely rare fulminant case of Edwardsiella tarda infection-related necrotizing fasciitis. The patient had alcoholic cirrhosis and preferred to consume raw fish. He experienced painful swelling of the right forearm one day after he got a minor injury when falling from the ladder, and visited our hospital. His accompanied symptoms were diarrhea and general fatigue. His consciousness got deteriorated after the admission. The lesion of the right forearm had spread and the color had deteriorated with epidermolysis in a few hours. Necrotizing soft-tissue infection was suspected, and emergency debridement of the swollen forearm was performed 4 hours after the admission. However, unfortunately, he died of sepsis approximately 5 hours later. Histological examination of the biopsy specimen revealed features consistent with those of necrotizing fasciitis. The bacterial cultures of blood and the wound identified E. tarda. Since this microorganism is usually isolated from aquatic environments and can cause intestinal infection, sometimes followed by bacteremia especially in immunocompromised hosts, two possible infection routes were suspected. One route was from the skin injury, leading to bacteremia. Another possible route was per oral: orally taken E. tarda invaded deeper tissues from the intestine and reach the bloodstream, leading to extraintestinal infections, although direct evidence remains elusive. Raw fish eaten 1 week prior is considered to be the most possible contaminated food. Overall mortality rate of E. tarda bacteremia is very high and the clinician should pay attention on characteristic clinical findings of E. tarda infection on cirrhotic patients.

Comparative analysis of human gut- and blood-derived mononuclear cells: contrasts in function and phenotype

Introduction

Alterations in the gut immune system have been implicated in various diseases.The challenge of obtaining gut tissues from healthy individuals, commonly performed via surgical explants, has limited the number of studies describing the phenotype and function of gut-derived immune cells in health.

Methods

Here, by means of recto-sigmoid colon biopsies obtained during routine care (colon cancer screening in healthy adults), the phenotype and function of immune cells present in the gut were described and compared to those found in blood.

Results

The proportion of CD4+, CD8+, MAIT, γδ+ T, and NK cells phenotype, expression of integrins, and ability to produce cytokine in response to stimulation with PMA and ionomycin. T cells in the gut were found to predominantly have a memory phenotype as compared to T cells in blood where a naïve phenotype predominates. Recto-sigmoid mononuclear cells also had higher PD-1 and Ki67 expression. Furthermore, integrin expression and cytokine production varied by cell type and location in blood vs. gut.

Discussion

These findings demonstrate the differences in functionality of these cells when compared to their blood counterparts and validate previous studies on phenotype within gut-derived immune cells in humans (where cells have been obtained through surgical means). This study suggests that recto-sigmoid biopsies collected during colonoscopy can be a reliable yet more accessible sampling method for follow up of alterations of gut derived immune cells in clinical settings.

Probiotics as Potential Therapeutic Agents: Safeguarding Skeletal Muscle against Alcohol-Induced Damage through the Gut-Liver-Muscle Axis

Probiotics have shown the potential to counteract the loss of muscle mass, reduce physical fatigue, and mitigate inflammatory response following intense exercise, although the mechanisms by which they work are not very clear. The objective of this review is to describe the main harmful effects of alcohol on skeletal muscle and to provide important strategies based on the use of probiotics. The excessive consumption of alcohol is a worldwide problem and has been shown to be crucial in the progression of alcoholic liver disease (ALD), for which, to date, the only therapy available is lifestyle modification, including cessation of drinking. In ALD, alcohol contributes significantly to the loss of skeletal muscle, and also to changes in the intestinal microbiota, which are the basis for a series of problems related to the onset of sarcopenia. Some of the main effects of alcohol on the skeletal muscle are described in this review, with particular emphasis on the "gut-liver-muscle axis", which seems to be the primary cause of a series of muscle dysfunctions related to the onset of ALD. The modulation of the intestinal microbiota through probiotics utilization has appeared to be crucial in mitigating the muscle damage induced by the high amounts of alcohol consumed.

Gut microbiota-derived indole compounds attenuate metabolic dysfunction-associated steatotic liver disease by improving fat metabolism and inflammation

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease, and its prevalence has increased worldwide in recent years. Additionally, there is a close relationship between MASLD and gut microbiota-derived metabolites. However, the mechanisms of MASLD and its metabolites are still unclear. We demonstrated decreased indole-3-propionic acid (IPA) and indole-3-acetic acid (IAA) in the feces of patients with hepatic steatosis compared to healthy controls. Here, IPA and IAA administration ameliorated hepatic steatosis and inflammation in an animal model of WD-induced MASLD by suppressing the NF-κB signaling pathway through a reduction in endotoxin levels and inactivation of macrophages. Bifidobacterium bifidum metabolizes tryptophan to produce IAA, and B. bifidum effectively prevents hepatic steatosis and inflammation through the production of IAA. Our study demonstrates that IPA and IAA derived from the gut microbiota have novel preventive or therapeutic potential for MASLD treatment.

Frailty in end-stage liver disease: Understanding pathophysiology, tools for assessment, and strategies for management

Frailty and sarcopenia are frequently observed in patients with end-stage liver disease. Frailty is a complex condition that arises from deteriorations across various physiological systems, including the musculoskeletal, cardiovascular, and immune systems, resulting in a reduced ability of the body to withstand stressors. This condition is associated with declined resilience and increased vulnerability to negative outcomes, including disability, hospitalization, and mortality. In cirrhotic patients, frailty is influenced by multiple factors, such as hyperammonemia, hormonal imbalance, malnutrition, ascites, hepatic encephalopathy, and alcohol intake. Assessing frailty is crucial in predicting morbidity and mortality in cirrhotic patients. It can aid in making critical decisions regarding patients' eligibility for critical care and transplantation. This, in turn, can guide the development of an individualized treatment plan for each patient with cirrhosis, with a focus on prioritizing exercise, proper nutrition, and appropriate treatment of hepatic complications as the primary lines of treatment. In this review, we aim to explore the topic of frailty in liver diseases, with a particular emphasis on pathophysiology, clinical assessment, and discuss strategies for preventing frailty through effective treatment of hepatic complications. Furthermore, we explore novel assessment and management strategies that have emerged in recent years, including the use of wearable technology and telemedicine.

Vitamin D deficiency exacerbates alcohol-related liver injury via gut barrier disruption and hepatic overload of endotoxin

Endogenous lipopolysaccharide (LPS) that translocates via the disrupted intestinal barrier plays an essential role in the progression of alcohol-related liver disease (ALD). Vitamin D deficiency is observed in ALD, and it participates in regulating gut barrier function. The current study aimed to examine the association between vitamin D deficiency and endotoxemia in patients with ALD-related cirrhosis. Moreover, the effect of vitamin D deficiency on ethanol (EtOH)- and carbon tetrachloride (CCl4)-induced liver injury relevant to gut barrier disruption in mice was investigated. Patients with ALD-related cirrhosis (Child-Pugh Class A/B/C; n=56/15/7) had lower 25(OH)D levels and higher endotoxin activities than non-drinking healthy controls (n=19). The serum 25(OH)D levels were found to be negatively correlated with endotoxin activity (R=-0.481, P<.0001). The EtOH/CCl4-treated mice developed hepatic inflammation and fibrosis, which were significantly enhanced by vitamin D-deficient diet. Vitamin D deficiency enhanced gut hyperpermeability by inhibiting the intestinal expressions of tight junction proteins including ZO-1, occludin, and claudin-2/5/12/15 in the EtOH/CCl4-treated mice. Consequently, it promoted the accumulation of lipid peroxidases, increased the expression of NADPH oxidases, and induced Kupffer cell infiltration and LPS/toll-like receptor 4 signaling-mediated proinflammatory response. Based on the in vitro assay, vitamin D-mediated vitamin D receptor activation inhibited EtOH-stimulated paracellular permeability and the downregulation of tight junction proteins via the upregulation of caudal-type homeobox 1 in Caco-2 cells. Hence, vitamin D deficiency exacerbates the pathogenesis of ALD via gut barrier disruption and hepatic overload of LPS.

NF-kB Regulation and the Chaperone System Mediate Restorative Effects of the Probiotic Lactobacillus fermentum LF31 in the Small Intestine and Cerebellum of Mice with Ethanol-Induced Damage

Probiotics are live microorganisms that yield health benefits when consumed, generally by improving or restoring the intestinal flora (microbiota) as part of the muco-microbiotic layer of the bowel. In this work, mice were fed with ethanol alone or in combination with the probiotic Lactobacillus fermentum (L. fermentum) for 12 weeks. The modulation of the NF-κB signaling pathway with the induction of Hsp60, Hsp90, and IkB-α by the probiotic occurred in the jejunum. L. fermentum inhibited IL-6 expression and downregulated TNF-α transcription. NF-κB inactivation concurred with the restoration of the intestinal barrier, which had been damaged by ethanol, via the production of tight junction proteins, ameliorating the ethanol-induced intestinal permeability. The beneficial effect of the probiotic on the intestine was repeated for the cerebellum, in which downregulation of glial inflammation-related markers was observed in the probiotic-fed mice. The data show that L. fermentum exerted anti-inflammatory and cytoprotective effects in both the small intestine and the cerebellum, by suppressing ethanol-induced increased intestinal permeability and curbing neuroinflammation. The results also suggest that L. fermentum could be advantageous, along with the other available means, for treating intestinal diseases caused by stressors associated with inflammation and dysbiosis.

Do gut microbiome-targeted therapies improve liver function in cirrhotic patients? A systematic review and meta-analysis

BACKGROUND AND AIM

Microbiome-targeted therapies (MTTs) are considered as promising interventions for cirrhosis, but the impact of gut microbiome modulation on liver function and disease severity has not been fully assessed. We comprehensively evaluated the efficacy of MTTs in patients with liver cirrhosis.

METHODS

Data from randomized controlled trials were collected through MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and ClinicalTrial.gov from inception to February 20, 2023. Clinical outcomes were pooled and expressed in terms of risk ratios or mean differences (MD). Additional subgroup and sensitivity analyses were performed to validate the robustness of findings. A trial sequential analysis was applied to calculate the required information size and evaluate the credibility of the meta-analysis results.

RESULTS

Twenty-one studies with a total of 1699 cirrhotic patients were included for meta-analysis. MTTs were associated with a significant reduction in aspartate aminotransferase (MD, -3.62; 95% CI, -6.59 to -0.65), the risk of hepatic encephalopathy (risk ratio = 0.56, 95% CI: 0.46 to 0.68), model for end-stage liver disease score (MD, -0.90; 95% CI, -1.17 to -0.11), ammonia (MD, -11.86; 95% CI, -16.39 to -7.33), and endotoxin (MD, -0.14; 95% CI, -0.23 to -0.04). The trial sequential analysis yielded reliable results of these outcomes. No effects were observed on the changes of other hepatic function indicators.

CONCLUSION

MTTs appeared to be associated with a slowed deterioration in liver cirrhosis, which could provide reference for clinicians in treatment of cirrhotic patients based on their conditions.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

The Intestinal Microbiota in the Development of Chronic Liver Disease: Current Status

Chronic liver disease (CLD) is a significant global health burden, leading to millions of deaths annually. The gut-liver axis plays a pivotal role in this context, allowing the transport of gut-derived products directly to the liver, as well as biological compounds from the liver to the intestine. The gut microbiota plays a significant role in maintaining the health of the digestive system. A change in gut microbiome composition as seen in dysbiosis is associated with immune dysregulation, altered energy and gut hormone regulation, and increased intestinal permeability, contributing to inflammatory mechanisms and damage to the liver, irrespective of the underlying etiology of CLD. The aim of this review is to present the current knowledge about the composition of the intestinal microbiome in healthy individuals and those with CLD, including the factors that affect this composition, the impact of the altered microbiome on the liver, and the mechanisms by which it occurs. Furthermore, this review analyzes the effects of gut microbiome modulation on the course of CLD, by using pharmacotherapy, nutrition, fecal microbiota transplantation, supplements, and probiotics. This review opens avenues for the translation of knowledge about gut-liver interplay into clinical practice as an additional tool to fight CLD and its complications.

New Insights into the Pathogenesis of Metabolic-Associated Fatty Liver Disease (MAFLD): Gut-Liver-Heart Crosstalk

Metabolism-associated fatty liver disease (MAFLD) is a multifaceted disease that involves complex interactions between various organs, including the gut and heart. It is defined by hepatic lipid accumulation and is related to metabolic dysfunction, obesity, and diabetes. Understanding the intricate interplay of the gut-liver-heart crosstalk is crucial for unraveling the complexities of MAFLD and developing effective treatment and prevention strategies. The gut-liver crosstalk participates in the regulation of the metabolic and inflammatory processes through host-microbiome interactions. Gut microbiota have been associated with the development and progression of MAFLD, and its dysbiosis contributes to insulin resistance, inflammation, and oxidative stress. Metabolites derived from the gut microbiota enter the systemic circulation and influence both the liver and heart, resulting in the gut-liver-heart axis playing an important role in MAFLD. Furthermore, growing evidence suggests that insulin resistance, endothelial dysfunction, and systemic inflammation in MAFLD may contribute to an increased risk of cardiovascular disease (CVD). Additionally, the dysregulation of lipid metabolism in MAFLD may also lead to cardiac dysfunction and heart failure. Overall, the crosstalk between the liver and heart involves a complex interplay of molecular pathways that contribute to the development of CVD in patients with MAFLD. This review emphasizes the current understanding of the gut-liver-heart crosstalk as a foundation for optimizing patient outcomes with MAFLD.

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.

Mean platelet volume and mortality in patients with alcohol use disorder

Several recent studies have pointed out the relationship of platelet size with increased mortality or adverse clinical course. Most studies show that increased mean platelet volume (MPV) may be associated with a deleterious outcome in different settings such as sepsis or neoplasia, whereas other researchers have found the opposite. In inflammatory conditions there is an altered secretion of several cytokines, some of them exerting a marked influence on platelet biogenesis and/or on platelet activation and aggregation. Alcohol use disorder is a chronic situation characterized by a protracted low-grade inflammation. In this study we analyze the relationship between proinflammatory cytokines and MPV and their relationships with mortality in patients with alcohol abuse. We determined serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-8 and routine laboratory variables among 184 patients with alcohol use disorder admitted to our hospital and followed-up for a median of 42 months. We found that MPV was inversely related to TNF-α (ρ=-0.34), and directly to IL-8 (ρ=0.32, p<0.001 in both cases) and to IL-6 (ρ=0.15; p = 0.046). Reduced MPV was related both with short-term (<6 months) and long-term mortality. Conclusion: These results suggest that inflammatory cytokines are strongly related to MPV. A low MPV is associated with a poor prognosis among patients with alcohol use disorder.

Enhanced lupus progression in alcohol-administered Fc gamma receptor-IIb-deficiency lupus mice, partly through leaky gut-induced inflammation

Alcohol can induce a leaky gut, with translocation of microbial molecules from the gut into the blood circulation. Although the contribution of inflammation to organ-mediated damage in lupus has been previously demonstrated, the mechanistic roles of alcohol consumption in lupus activation are not known. Herein, we tested the effects of 10-week lasting alcohol administration on organ damages and immune responses in 8-week-old lupus-prone Fc gamma receptor IIb-deficient (FcγRIIb-/- ) mice. Our study endpoints were evaluation of systemic inflammation and assessment of fecal dysbiosis along with endotoxemia. In comparison with alcohol-administered wild-type mice, FcγRIIb-/- mice demonstrated more prominent liver damage (enzyme, histological score, apoptosis, malondialdehyde oxidant) and serum interleukin(IL)-6 levels, despite a similarity in leaky gut (fluorescein isothiocyanate-dextran assay, endotoxemia and gut occludin-1 immunofluorescence), fecal dysbiosis (microbiome analysis) and endotoxemia. All alcohol-administered FcγRIIb-/- mice developed lupus-like characteristics (serum anti-dsDNA, proteinuria, serum creatinine and kidney injury score) with spleen apoptosis, whereas control FcγRIIb-/- mice showed only a subtle anti-dsDNA. Both alcohol and lipopolysaccharide (LPS) similarly impaired enterocyte integrity (transepithelial electrical resistance), and only LPS, but not alcohol, upregulated the IL-8 gene in Caco-2 cells. In macrophages, alcohol mildly activated supernatant cytokines (tumor necrosis factor-α and IL-6), but not M1 polarization-associated genes (IL-1β and iNOS), whereas LPS prominently induced both parameters (more prominent in FcγRIIb-/- macrophages than wild type). There was no synergy in LPS plus alcohol compared with LPS alone in both enterocytes and macrophages. In conclusion, alcohol might exacerbate lupus-like activity partly through a profound inflammation from the leaky gut in FcγRIIb-/- mice.

The outcome of boosting mitochondrial activity in alcohol-associated liver disease is organ-dependent

BACKGROUND AND AIMS

Alcohol-associated liver disease (ALD) accounts for 70% of liver-related deaths in Europe, with no effective approved therapies. Although mitochondrial dysfunction is one of the earliest manifestations of alcohol-induced injury, restoring mitochondrial activity remains a problematic strategy due to oxidative stress. Here, we identify methylation-controlled J protein (MCJ) as a mediator for ALD progression and hypothesize that targeting MCJ may help in recovering mitochondrial fitness without collateral oxidative damage.

APPROACH AND RESULTS

C57BL/6 mice [wild-type (Wt)] Mcj knockout and Mcj liver-specific silencing (MCJ-LSS) underwent the NIAAA dietary protocol (Lieber-DeCarli diet containing 5% (vol/vol) ethanol for 10 days, plus a single binge ethanol feeding at day 11). To evaluate the impact of a restored mitochondrial activity in ALD, the liver, gut, and pancreas were characterized, focusing on lipid metabolism, glucose homeostasis, intestinal permeability, and microbiota composition. MCJ, a protein acting as an endogenous negative regulator of mitochondrial respiration, is downregulated in the early stages of ALD and increases with the severity of the disease. Whole-body deficiency of MCJ is detrimental during ALD because it exacerbates the systemic effects of alcohol abuse through altered intestinal permeability, increased endotoxemia, and dysregulation of pancreatic function, which overall worsens liver injury. On the other hand, liver-specific Mcj silencing prevents main ALD hallmarks, that is, mitochondrial dysfunction, steatosis, inflammation, and oxidative stress, as it restores the NAD + /NADH ratio and SIRT1 function, hence preventing de novo lipogenesis and improving lipid oxidation.

CONCLUSIONS

Improving mitochondrial respiration by liver-specific Mcj silencing might become a novel therapeutic approach for treating ALD.

Ginsenoside Rk2, a dehydroprotopanaxadiol saponin, alleviates alcoholic liver disease via regulating NLRP3 and NLRP6 inflammasome signaling pathways in mice

Heavy alcohol consumption results in alcoholic liver disease (ALD) with inadequate therapeutic options. Here, we first report the potential beneficial effects of ginsenoside Rk2 (Rk2), a rare dehydroprotopanaxadiol saponin isolated from streamed ginseng, against alcoholic liver injury in mice. Chronic-plus-single-binge ethanol feeding caused severe liver injury, as manifested by significantly elevated serum aminotransferase levels, hepatic histological changes, increased lipid accumulation, oxidative stress, and inflammation in the liver. These deleterious effects were alleviated by the treatment with Rk2 (5 and 30 mg/kg). Acting as an nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inhibitor, Rk2 ameliorates alcohol-induced liver inflammation by inhibiting NLRP3 inflammasome signaling in the liver. Meanwhile, the treatment with Rk2 alleviated the alcohol-induced intestinal barrier dysfunction via enhancing NLRP6 inflammasome in the intestine. Our findings indicate that Rk2 is a promising agent for the prevention and treatment of ALD and other NLPR3-driven diseases.

Acetobacter pasteurianus BP2201 alleviates alcohol-induced hepatic and neuro-toxicity and modulate gut microbiota in mice

The excessive consumption of alcohol results in a dysbiosis of the gut microbiota, which subsequently impairs the gut microbiota-brain/liver axes and induces cognitive dysfunction and hepatic injury. This study aimed to investigate the potential effect of Acetobacter pasteurianus BP2201 in reducing the negative effects of alcohol consumption on cognitive function and liver health by modulating the gut microbiota-brain/liver axes. Treatment with A. pasteurianus BP2201 improved alcohol-induced hippocampal damage, suppressed neuroinflammation, promoted neuroprotein expression in the hippocampus and enhanced cognitive function. At the same time, A. pasteurianus BP2201 can also reduce serum lipid levels, relieve oxidative stress, inhibit TLR4/MyD88/NF-κB pathway, reduce the secretion of TNF-α and IL-1β, so as to improve alcoholic liver injury. Concomitantly, the treatment with A. pasteurianus BP2201 leads to a shift in the intestinal microbiota structure towards that of healthy individuals, inhibiting the proliferation of harmful bacteria and promoting the recovery of beneficial bacteria. In addition, it also improves brain cognitive dysfunction and liver health by affecting the gut microbiota-brain/liver axes by promoting the synthesis of relevant amino acids and the metabolism of nucleotide base components. These findings demonstrate the potential of regulating the gut microbiome and gut microbiota-brain/liver axes to mitigate alcohol-induced disease.

Alcohol consumption promotes arsenic absorption but reduces tissue arsenic accumulation in mice

Alcohol consumption alters gut microflora and damages intestinal tight junction barriers, which may affect arsenic (As) oral bioavailability. In this study, mice were exposed to arsenate in the diet (6 μg/g) over a 3-week period and gavaged daily with Chinese liquor (0.05 or 0.10 mL per mouse per day). Following ingestion, 78.0% and 72.9% of the total As intake was absorbed and excreted via urine when co-exposed with liquor at daily doses of 0.05 or 0.10 mL, significantly greater than when As was supplied alone (44.7%). Alcohol co-exposure significantly altered gut microbiota but did not significantly alter As biotransformation in the intestinal tract or tissue. Significantly lower relative mRNA expression was observed for genes encoding for tight junctions in the ileum of liquor co-exposed mice, contributing to greater As bioavailability attributable to enhanced As absorption via the intestinal paracellular pathway. However, As concentration in the liver, kidney, and intestinal tissue of liquor-treated mice was decreased by 24.4%-42.6%, 27.5%-38.1%, and 28.1%-48.9% compared to control mice. This was likely due to greater renal glomerular filtration rate induced by alcohol, as suggested by significantly lower expression of genes encoding for renal tight junctions. In addition, in mice gavaged daily with 0.05 mL liquor, the serum antidiuretic hormone level was significantly lower than control mice (2.83 ± 0.59 vs. 5.40 ± 1.10 pg/mL), suggesting the diuretic function of alcohol consumption, which may facilitate As elimination via urine. These results highlight that alcohol consumption has a significant impact on the bioavailability and accumulation of As.

Dihydromyricetin supplementation improves ethanol-induced lipid accumulation and inflammation

Introduction

Excessive alcohol consumption leads to a myriad of detrimental health effects, including alcohol-associated liver disease (ALD). Unfortunately, no available treatments exist to combat the progression of ALD beyond corticosteroid administration and/or liver transplants. Dihydromyricetin (DHM) is a bioactive polyphenol and flavonoid that has traditionally been used in Chinese herbal medicine for its robust antioxidant and anti-inflammatory properties. It is derived from many plants, including Hovenia dulcis and is found as the active ingredient in a variety of popular hangover remedies. Investigations utilizing DHM have demonstrated its ability to alleviate ethanol-induced disruptions in mitochondrial and lipid metabolism, while demonstrating hepatoprotective activity.

Methods

Female c57BL/6J mice (n = 12/group) were treated using the Lieber DeCarli forced-drinking and ethanol (EtOH) containing liquid diet, for 5 weeks. Mice were randomly divided into three groups: (1) No-EtOH, (2) EtOH [5% (v/v)], and (3) EtOH [5% (v/v)] + DHM (6 mg/mL). Mice were exposed to ethanol for 2 weeks to ensure the development of ALD pathology prior to receiving dihydromyricetin supplementation. Statistical analysis included one-way ANOVA along with Bonferroni multiple comparison tests, where p ≤ 0.05 was considered statistically significant.

Results

Dihydromyricetin administration significantly improved aminotransferase levels (AST/ALT) and reduced levels of circulating lipids including LDL/VLDL, total cholesterol (free cholesterol), and triglycerides. DHM demonstrated enhanced lipid clearance by way of increased lipophagy activity, shown as the increased interaction and colocalization of p62/SQSTM-1, LC3B, and PLIN-1 proteins. DHM-fed mice had increased hepatocyte-to-hepatocyte lipid droplet (LD) heterogeneity, suggesting increased neutralization and sequestration of free lipids into LDs. DHM administration significantly reduced prominent pro-inflammatory cytokines commonly associated with ALD pathology such as TNF-α, IL-6, and IL-17.

Discussion

Dihydromyricetin is commercially available as a dietary supplement. The results of this proof-of-concept study demonstrate its potential utility and functionality as a cost-effective and safe candidate to combat inflammation and the progression of ALD pathology.

Alcohol and its associated liver carcinogenesis

Alcohol consumption is a major cause of cirrhosis and hepatocellular carcinoma (HCC). The prevalence of alcohol-associated hepatocellular carcinoma (aHCC) varies worldwide but is highest in Eastern Europe. Alcohol is the second fastest-growing cause of age-standardized liver cancer mortality with tumors more often diagnosed outside surveillance protocols and at a more advanced stage. Risk factors for aHCC include greater amounts of alcohol consumption, sex, and certain genetic polymorphisms. Smoking, concomitant liver disease, obesity, and diabetes act synergistically in increasing the risk of HCC in alcohol-associated liver disease. Alcohol-related hepatocarcinogenesis results from the complex interactions of several mechanistic pathways. Although not completely understood, underlying mechanisms include acetaldehyde-related hepatotoxicity, oxidative stress, activation of the innate immune system, and alterations of the host microbiome.

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.

Biomarkers of gut barrier dysfunction and risk of hepatocellular carcinoma in the REVEAL-HBV and REVEAL-HCV cohort studies

Gut barrier dysfunction can result in the liver being exposed to an elevated level of gut-derived bacterial products via portal circulation. Growing evidence suggests that systemic exposure to these bacterial products promotes liver diseases including hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). However, prospective studies have not examined the association between biomarkers of gut barrier dysfunction and HCC risk in a population of hepatitis B or C viral (HBV/HCV) carriers. We investigated whether prediagnostic, circulating biomarkers of gut barrier dysfunction were associated with HCC risk, using the Risk Evaluation of Viral Load Elevation and Associated Liver Disease/Cancer (REVEAL)-HBV and REVEAL-HCV cohorts from Taiwan. REVEAL-HBV included 185 cases and 161 matched controls, and REVEAL-HCV 96 cases and 96 matched controls. The biomarkers quantitated were immunoglobulin A (IgA), IgG, and IgM against lipopolysaccharide (LPS) and flagellin, soluble CD14 (an LPS coreceptor), and LPS-binding protein (LBP). Odds ratios (ORs) and 95% confidence intervals (CIs) for associations between biomarker levels and HCC were calculated using multivariable-adjusted logistic regression. A doubling of the circulating levels of antiflagellin IgA or LBP was associated with a 76% to 93% increased risk of HBV-related HCC (OR per one unit change in log2 antiflagellin IgA = 1.76, 95% CI: 1.06-2.93; OR for LBP = 1.93, 95% CI: 1.10-3.38). None of the other markers were associated with an increased risk of HBV-related or HCV-related HCC. Results were similar when cases diagnosed in the first 5 years of follow-up were excluded. Our findings contribute to understanding the interplay of gut barrier dysfunction and primary liver cancer etiology.

Potential Benefits of Epidermal Growth Factor for Inhibiting Muscle Degrative Markers in Rats with Alcoholic Liver Damage

This study investigated the beneficial effects of epidermal growth factor (EGF) on muscle loss in rats with chronic ethanol feeding. Six-week-old male Wistar rats were fed either a control liquid diet without EGF (C group, n = 12) or EGF (EGF-C group, n = 18) for two weeks. From the 3rd to 8th week, the C group was divided into two groups. One was continually fed with a control liquid diet (C group), and the other one was fed with an ethanol-containing liquid diet (E group); moreover, the EGF-C group was divided into three groups, such as the AEGF-C (continually fed with the same diet), PEGF-E (fed with the ethanol-containing liquid diet without EGF), and AEGF-E (fed with the ethanol-containing liquid diet with EGF). As a result, the E group had significantly higher plasma ALT and AST, endotoxin, ammonia, and interleukin 1b (IL-1b) levels, along with liver injuries, such as hepatic fatty changes and inflammatory cell infiltration. However, plasma endotoxin and IL-1b levels were significantly decreased in the PEGF-E and AEGF-E groups. In addition, the protein level of muscular myostatin and the mRNA levels of forkhead box transcription factors (FOXO), muscle RING-finger protein-1 (MURF-1) and atorgin-1 was increased considerably in the E group but inhibited in the PEGF-E and AEGF-E groups. According to the principal coordinate analysis findings, the gut microbiota composition differed between the control and ethanol liquid diet groups. In conclusion, although there was no noticeable improvement in muscle loss, EGF supplementation inhibited muscular protein degradation in rats fed with an ethanol-containing liquid diet for six weeks. The mechanisms might be related to endotoxin translocation inhibition, microbiota composition alteration as well as the amelioration of liver injury. However, the reproducibility of the results must be confirmed in future studies.

Fpr2-/- Mice Developed Exacerbated Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) is the most common chronic liver disease and carries a significant healthcare burden. ALD has no long-term treatment options aside from abstinence, and the mechanisms that contribute to its pathogenesis are not fully understood. This study aimed to investigate the role of formyl peptide receptor 2 (FPR2), a receptor for immunomodulatory signals, in the pathogenesis of ALD. WT and Fpr2-/- mice were exposed to chronic-binge ethanol administration and subsequently assessed for liver injury, inflammation, and markers of regeneration. The differentiation capacity of liver macrophages and the oxidative burst activity of neutrophils were also examined. Compared to WT, Fpr2-/- mice developed more severe liver injury and inflammation and had compromised liver regeneration in response to ethanol administration. Fpr2-/- mice had fewer hepatic monocyte-derived restorative macrophages, and neutrophils isolated from Fpr2-/- mice had diminished oxidative burst capacity. Fpr2-/- MoMF differentiation was restored when co-cultured with WT neutrophils. Loss of FPR2 led to exacerbated liver damage via multiple mechanisms, including abnormal immune responses, indicating the crucial role of FPR2 in ALD pathogenesis.

Compound Probiotic Ameliorates Acute Alcoholic Liver Disease in Mice by Modulating Gut Microbiota and Maintaining Intestinal Barrier

Alcoholic liver disease (ALD) is a worldwide health threaten lack of effective treatment. Gut dysbiosis and concomitant augmented intestinal permeability are strongly implicated in the pathogenesis and progression of ALD. Research on the protective effect of probiotics on ALD is limited, and more effective intestinal microecological regulators and the related mechanisms still need to be further explored. In the present study, the protective effects and mechanisms of a compound probiotic against acute alcohol-induced liver injury in vivo were explod. It was showed that the compound probiotic ameliorated liver injury in acute ALD mice and stabilized the levels of ALT, AST, and TG in serum. The compound probiotic reversed acute alcohol-induced gut dysbiosis and maintained the intestinal barrier integrity by upregulating the production of mucus and the expression of tight junction (TJ) proteins and thus reduced LPS level in liver. Meanwhile, the compound probiotic reduced inflammation level by inhibiting TLR4/NF-κB signaling pathway and suppressed oxidative stress level in liver. Furthermore, the compound probiotic alleviated liver lipid accumulation by regulating fatty acid metabolism-associated genes and AMPK-PPARα signaling pathway. Noteworthy, fecal microbiota transplantation (FMT) realized comparable protective effect with that of compound probiotic. In conclusion, present study demonstrates the beneficial effects and underlying mechanism of the compound probiotic against acute alcohol-induced liver injury. It provides clues for development of novel strategy for treatment of ALD.

TRPV6 deficiency attenuates stress and corticosterone-mediated exacerbation of alcohol-induced gut barrier dysfunction and systemic inflammation

Introduction

Chronic stress is co-morbid with alcohol use disorder that feedback on one another, thus impeding recovery from both disorders. Stress and the stress hormone corticosterone aggravate alcohol-induced intestinal permeability and liver damage. However, the mechanisms involved in compounding tissue injury by stress/corticosterone and alcohol are poorly defined. Here we explored the involvement of the TRPV6 channel in stress (or corticosterone) 3and alcohol-induced intestinal epithelial permeability, microbiota dysbiosis, and systemic inflammation.

Methods

Chronic alcohol feeding was performed on adult wild-type and Trpv6-/- mice with or without corticosterone treatment or chronic restraint stress (CRS). The barrier function was determined by evaluating inulin permeability in vivo and assessing tight junction (TJ) and adherens junction (AJ) integrity by immunofluorescence microscopy. The gut microbiota composition was evaluated by 16S rRNA sequencing and metagenomic analyses. Systemic responses were assessed by evaluating endotoxemia, systemic inflammation, and liver damage.

Results

Corticosterone and CRS disrupted TJ and AJ, increased intestinal mucosal permeability, and caused endotoxemia, systemic inflammation, and liver damage in wild-type but not Trpv6-/- mice. Corticosterone and CRS synergistically potentiated the alcohol-induced breakdown of intestinal epithelial junctions, mucosal barrier impairment, endotoxemia, systemic inflammation, and liver damage in wild-type but not Trpv6-/- mice. TRPV6 deficiency also blocked the effects of CRS and CRS-mediated potentiation of alcohol-induced dysbiosis of gut microbiota.

Conclusions

These findings indicate an essential role of TRPV6 in stress, corticosterone, and alcohol-induced intestinal permeability, microbiota dysbiosis, endotoxemia, systemic inflammation, and liver injury. This study identifies TRPV6 as a potential therapeutic target for developing treatment strategies for stress and alcohol-associated comorbidity.

Recent Advances in Understanding of Pathogenesis of Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) is one of the major diseases arising from chronic alcohol consumption and is one of the most common causes of liver-related morbidity and mortality. ALD includes asymptomatic liver steatosis, fibrosis, cirrhosis, and alcohol-associated hepatitis and its complications. The progression of ALD involves complex cell-cell and organ-organ interactions. We focus on the impact of alcohol on dysregulation of homeostatic mechanisms and regulation of injury and repair in the liver. In particular, we discuss recent advances in understanding the disruption of balance between programmed cell death and prosurvival pathways, such as autophagy and membrane trafficking, in the pathogenesis of ALD. We also summarize current understanding of innate immune responses, liver sinusoidal endothelial cell dysfunction and hepatic stellate cell activation, and gut-liver and adipose-liver cross talk in response to ethanol. In addition,we describe the current potential therapeutic targets and clinical trials aimed at alleviating hepatocyte injury, reducing inflammatory responses, and targeting gut microbiota, for the treatment of ALD.

Endotoxemia and Gastrointestinal Cancers: Insight into the Mechanisms Underlying a Dangerous Relationship

Lipopolysaccharide (LPS), also known as endotoxin, is a component of the membrane of gram-negative bacteria and a well-recognized marker of sepsis. In case of disruption of the intestinal barrier, as occurs with unhealthy diets, alcohol consumption, or during chronic diseases, the microbiota residing in the gastrointestinal tract becomes a crucial factor in amplifying the systemic inflammatory response. Indeed, the translocation of LPS into the bloodstream and its interaction with toll-like receptors (TLRs) triggers molecular pathways involved in cytokine release and immune dysregulation. This is a critical step in the exacerbation of many diseases, including metabolic disorders and cancer. Indeed, the role of LPS in cancer development is widely recognized, and examples include gastric tumor related to Helicobacter pylori infection and hepatocellular carcinoma, both of which are preceded by a prolonged inflammatory injury; in addition, the risk of recurrence and development of metastasis appears to be associated with endotoxemia. Here, we review the mechanisms that link the promotion and progression of tumorigenesis with endotoxemia, and the possible therapeutic interventions that can be deployed to counteract these events.

The Gut-Vascular Barrier as a New Protagonist in Intestinal and Extraintestinal Diseases

The intestinal barrier, with its multiple layers, is the first line of defense between the outside world and the intestine. Its disruption, resulting in increased intestinal permeability, is a recognized pathogenic factor of intestinal and extra-intestinal diseases. The identification of a gut-vascular barrier (GVB), consisting of a structured endothelium below the epithelial layer, has led to new evidence on the etiology and management of diseases of the gut-liver axis and the gut-brain axis, with recent implications in oncology as well. The gut-brain axis is involved in several neuroinflammatory processes. In particular, the recent description of a choroid plexus vascular barrier regulating brain permeability under conditions of gut inflammation identifies the endothelium as a key regulator in maintaining tissue homeostasis and health.

Emerging Biomarkers in Alcohol-associated Hepatitis

Alcohol-associated hepatitis (AH) is a clinical syndrome of jaundice, abdominal pain, and anorexia due to prolonged heavy alcohol intake. AH is associated with changes in gene expression, cytokines, immune response, and the gut microbiome. There are limited biomarkers to diagnose and prognosticate in AH, but several non-invasive biomarkers are emerging. In this review, clinical risk-stratifying algorithms, promising AH biomarkers like cytokeratin-18 fragments, genetic polymorphisms, and microRNAs will be reviewed.

The Interplay Between Gut Microbiota and Central Nervous System

This review highlights the relationships between gastrointestinal microorganisms and the brain. The gut microbiota communicates with the central nervous system through nervous, endocrine, and immune signalling mechanisms. Our brain can modulate the gut microbiota structure and function through the autonomic nervous system, and possibly through neurotransmitters which directly act on bacterial gene expression. In this context, oxidative stress is one the main factors involved in the dysregulation of the gut-brain axis and consequently in neurodegenerative disorders. Several factors influence the susceptibility to oxidative stress by altering the antioxidant status or free oxygen radical generation. Amongst these, of interest is alcohol, a commonly used substance which can negatively influence the central nervous system and gut microbiota, with a key role in the development of neurodegenerative disorder. The role of "psychobiotics" as a novel contrast strategy for preventing and treating disorders caused due to alcohol use and abuse has been investigated.

The interplay between nonalcoholic fatty liver disease and atherosclerotic cardiovascular disease

Therapeutic approaches that lower circulating low-density lipoprotein (LDL)-cholesterol significantly reduced the burden of cardiovascular disease over the last decades. However, the persistent rise in the obesity epidemic is beginning to reverse this decline. Alongside obesity, the incidence of nonalcoholic fatty liver disease (NAFLD) has substantially increased in the last three decades. Currently, approximately one third of world population is affected by NAFLD. Notably, the presence of NAFLD and particularly its more severe form, nonalcoholic steatohepatitis (NASH), serves as an independent risk factor for atherosclerotic cardiovascular disease (ASCVD), thus, raising interest in the relationship between these two diseases. Importantly, ASCVD is the major cause of death in patients with NASH independent of traditional risk factors. Nevertheless, the pathophysiology linking NAFLD/NASH with ASCVD remains poorly understood. While dyslipidemia is a common risk factor underlying both diseases, therapies that lower circulating LDL-cholesterol are largely ineffective against NASH. While there are no approved pharmacological therapies for NASH, some of the most advanced drug candidates exacerbate atherogenic dyslipidemia, raising concerns regarding their adverse cardiovascular consequences. In this review, we address current gaps in our understanding of the mechanisms linking NAFLD/NASH and ASCVD, explore strategies to simultaneously model these diseases, evaluate emerging biomarkers that may be useful to diagnose the presence of both diseases, and discuss investigational approaches and ongoing clinical trials that potentially target both diseases.

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.

Lactobacillus plantarum J26 Alleviating Alcohol-Induced Liver Inflammation by Maintaining the Intestinal Barrier and Regulating MAPK Signaling Pathways

Alcoholic liver disease (ALD), as a global health problem, is mainly caused by liver inflammation. Meanwhile, probiotics have been considered as a potential and promising strategy to prevent and alleviate ALD. This study aimed to investigate the ameliorative effect of pre-intaking with Lactobacillus plantarum J26 (L. plantarum J26) on alcohol-induced liver inflammation, with emphasis on the underlying mechanism for alleviating ALD. The results indicated that L. plantarum J26 could reduce the abundance of Gram-negative pathogenic bacteria by regulating the gut microbiota in mice with alcoholic liver injury, thereby reducing the lipopolysaccharide (LPS) content in the intestine. In addition, L. plantarum J26 could also maintain the intestinal barrier, prevent LPS from crossing the intestinal barrier to correct disorders of the gut-liver axis and then inhibit the activation of Toll-like receptor 4 (TLR4)-mediated MAPK signaling pathway, reducing liver inflammation and restoring liver functions. In conclusion, pre-intake of L. plantarum J26 could alleviate alcohol-induced liver inflammation, which may be closely related to the role of intestinal microbiota in regulating and maintaining the intestinal barrier and then regulating the MAPK signaling pathway.

ALDH2 deficiency increases susceptibility to binge alcohol-induced gut leakiness, endotoxemia, and acute liver injury in mice through the gut-liver axis

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is the major enzyme responsible for metabolizing toxic acetaldehyde to acetate and acts as a protective or defensive protein against various disease states associated with alcohol use disorder (AUD), including alcohol-related liver disease (ARLD). We hypothesized that Aldh2-knockout (KO) mice are more susceptible to binge alcohol-mediated liver injury than wild-type (WT) mice through increased oxidative stress, gut leakiness and endotoxemia. Therefore, this study aimed to investigate the protective role of ALDH2 in binge alcohol-induced gut permeability, endotoxemia, and acute inflammatory liver injury by exposing Aldh2-KO or WT mice to a single oral dose of binge alcohol 3.5, 4.0, or 5.0 g/kg. Our findings showed for the first time that ALDH2 deficiency in Aldh2-KO mice increases their sensitivity to binge alcohol-induced oxidative and nitrative stress, enterocyte apoptosis, and nitration of gut tight junction (TJ) and adherent junction (AJ) proteins, leading to their degradation. These resulted in gut leakiness and endotoxemia in Aldh2-KO mice after exposure to a single dose of ethanol even at 3.5 g/kg, while no changes were observed in the corresponding WT mice. The elevated serum endotoxin (lipopolysaccharide, LPS) and bacterial translocation contributed to systemic inflammation, hepatocyte apoptosis, and subsequently acute liver injury through the gut-liver axis. Treatment with Daidzin, an ALDH2 inhibitor, exacerbated ethanol-induced cell permeability and reduced TJ/AJ proteins in T84 human colon cells. These changes were reversed by Alda-1, an ALDH2 activator. Furthermore, CRISPR/Cas9-mediated knockout of ALDH2 in T84 cells increased alcohol-mediated cell damage and paracellular permeability. All these findings demonstrate the critical role of ALDH2 in alcohol-induced epithelial barrier dysfunction and suggest that ALDH2 deficiency or gene mutation in humans is a risk factor for alcohol-mediated gut and liver injury, and that ALDH2 could be an important therapeutic target against alcohol-associated tissue or organ damage.

Morinda citrifolia Extract Prevents Alcoholic Fatty Liver Disease by Improving Gut Health

Alcoholic liver disease (ALD) is a major chronic liver disease. Chronic alcohol consumption induces dysbiosis, disruption of gut barrier function, oxidative stress, inflammation, and changes in lipid metabolism, thereby leading to ALD. In this study, we investigated whether the commercial Morinda citrifolia extract Nonitri can ameliorate ALD symptoms through the gut-liver axis. We used mice chronically administered EtOH and found a marked increase in serum endotoxin levels and biomarkers of liver pathology. Moreover, the EtOH-treated group showed significantly altered gut microbial composition particularly that of Alistipes, Bacteroides, and Muribaculum and disrupted gut barrier function. However, Nonitri improved serum parameters, restored the microbial proportions, and regulated levels of zonula occludens1, occludin, and claudin1. Furthermore, Nonitri suppressed inflammation by inhibiting endotoxin-triggered toll-like receptor 4-signaling pathway and fat deposition by reducing lipogenesis through activating AMP-activated protein kinase in the liver. Furthermore, Pearson's correlation analysis showed that gut microbiota and ALD-related markers were correlated, and Nonitri regulated these bacteria. Taken together, our results indicate that the hepatoprotective effect of Nonitri reduces endotoxin levels by improving gut health, and inhibits fat deposition by regulating lipid metabolism.

Resident macrophages of the lung and liver: The guardians of our tissues

Resident macrophages play a unique role in the maintenance of tissue function. As phagocytes, they are an essential first line defenders against pathogens and much of the initial characterization of these cells was focused on their interaction with viral and bacterial pathogens. However, these cells are increasingly recognized as contributing to more than just host defense. Through cytokine production, receptor engagement and gap junction communication resident macrophages tune tissue inflammatory tone, influence adaptive immune cell phenotype and regulate tissue structure and function. This review highlights resident macrophages in the liver and lung as they hold unique roles in the maintenance of the interface between the circulatory system and the external environment. As such, we detail the developmental origin of these cells, their contribution to host defense and the array of tools these cells use to regulate tissue homeostasis.

Causes and outcomes of hepatic fibrosis in persons living with HIV

PURPOSE OF REVIEW

The epidemiology of liver disease in people living with HIV has evolved since the arrival of effective hepatitis C virus (HCV) treatment. Nonalcoholic fatty liver disease (NAFLD) in HIV patients is highly prevalent while hepatitis D, hepatitis E, and occult hepatitis B remain underappreciated. We discuss mechanisms of fibrosis in HIV and review clinical outcomes of HIV-associated liver diseases.

RECENT FINDINGS

HIV-HCV co-infection is receding as a cause of progressive liver disease, but fibrosis biomarkers after HCV treatment remain elevated. Antiretroviral therapy (ART) with anti-hepatitis B virus (HBV) activity promotes stable liver disease, but oversimplifying ART regimens in unrecognized suppressed HBV may lead to activation of HBV. A high prevalence of fibrosis and rapid progression of fibrosis are seen in HIV-associated NAFLD, with visceral fat as a major risk factor. Newer ART such as integrase strand inhibitors may have limited intrinsic hepatoxicity but do increase weight, which may secondarily lead to hepatic steatosis. Promising therapies for HIV-associated NAFLD include tesamorelin and CCR5 blockade agents.

SUMMARY

Our understanding of the natural history and pathogenesis of liver diseases in HIV has advanced and adapted to the changing landscape of liver disease in this population. Future research should evaluate long-term clinical and histological outcomes, prevention strategies, and treatment options to improve morbidity and mortality in HIV-related liver diseases.

Folic acid ameliorates alcohol-induced liver injury via gut–liver axis homeostasis

The gut–liver axis (GLA) plays an important role in the development of alcohol-induced liver injury. Alcohol consumption is typically associated with folic acid deficiency. However, no clear evidence has confirmed the effect of folic acid supplementation on alcohol-induced liver injury via GLA homeostasis. In this study, male C57BL/6J mice were given 56% (v/v) ethanol and 5.0 mg/kg folic acid daily by gavage for 10 weeks to investigate potential protective mechanisms of folic acid in alcohol-induced liver injury via GLA homeostasis. Histopathological and biochemical analyses showed that folic acid improved lipid deposition and inflammation in the liver caused by alcohol consumption and decreased the level of ALT, AST, TG, and LPS in serum. Folic acid inhibited the expression of the TLR4 signaling pathway and its downstream inflammatory mediators in the liver and upregulated the expression of ZO-1, claudin 1, and occludin in the intestine. But compared with the CON group, folic acid did not completely eliminate alcohol-induced intestine and liver injury. Furthermore, folic acid regulated alcohol-induced alterations in gut microbiota. In alcohol-exposed mice, the relative abundance of Bacteroidota was significantly increased, and the relative abundance of unclassified_Lachnospiraceae was significantly decreased. Folic acid supplementation significantly increased the relative abundance of Verrucomicrobia, Lachnospiraceae_NK4A136_group and Akkermansia, and decreased the relative abundance of Proteobacteria. The results of Spearman’s correlation analysis showed that serum parameters and hepatic inflammatory cytokines were significantly correlated with several bacteria, mainly including Bacteroidota, Firmicutes, and unclassified_Lachnospiraceae. In conclusion, folic acid could ameliorate alcohol-induced liver injury in mice via GLA homeostasis to some extent, providing a new idea and method for prevention of alcohol-induced liver injury.

IL-1 receptor antagonist plus pentoxifylline and zinc for severe alcohol-associated hepatitis

BACKGROUND AND AIMS

Patients with severe alcohol-associated hepatitis (AH) have high mortality. Corticosteroids improve survival only for 30 days. We targeted inflammation, cellular injury, and gut leakiness in a randomized clinical trial comparing combination therapy to corticosteroids on 180-day survival.

APPROACH AND RESULTS

Subjects with a clinical diagnosis of severe AH (Model for End-Stage Liver Disease [MELD] >20, Maddrey discriminant function [MDF] >32) were randomized to receive methylprednisolone (PRED; 28 days) or a combination of anakinra (14 days) plus pentoxifylline (28 days) plus zinc (COMB; 180 days). The primary endpoint was survival at 180 days. The study was designed in 2013, initiated in October 2014, and completed in March 2018. Five hundred patients were screened to randomize 104 subjects with a clinical diagnosis of AH with a MELD score >20. Fifty-three patients were randomized into the COMB and 50 to the PRED treatment; 1 dropped out of the study before randomization. Mean age was 45.3 ± 10.4 years; 60.6% were males, 92.3% White, and mean MELD 25.7 ± 3.9. Kaplan-Meier survival estimate at 180 days was 67.9% in COMB and 56% in PRED (HR = 0.69; p = 0.3001). Survival curves separated by 90 days (COMB, 69.8%; PRED, 58.0%; HR = 0.69; p = 0.28). Survival at 28 days was similar between the COMB (83.4%) and PRED groups (81.2%; HR = 0.91; p = 0.85). There were no unexpected serious adverse events, and incidence of infection was comparable between groups. MELD 20-25 and MELD >26 strata showed nonsignificant treatment effects in favor of COMB.

CONCLUSIONS

A combination of anakinra, pentoxifylline plus zinc provides similar survival benefits compared to corticosteroid therapy in severe AH.

Hepatocellular Carcinoma: Understanding the Inflammatory Implications of the Microbiome

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. It is well known that repeated inflammatory insults in the liver can cause hepatic cellular injury that lead to cirrhosis and, ultimately, hepatocellular carcinoma. Furthermore, the microbiome has been implicated in multiple inflammatory conditions which predispose patients to malignancy. With this in mind, we explore the inflammatory implications of the microbiome on pathways that lead to HCC. We also focus on how an understanding of these underlying inflammatory principles lead to a more wholistic understanding of this deadly disease, as well as potential therapeutic implications.

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.

Plasticity of monocytes and macrophages in cirrhosis of the liver

Cirrhosis of the liver is a systemic condition with raising prevalence worldwide. Patients with cirrhosis are highly susceptible to develop bacterial infections leading to acute decompensation and acute-on-chronic liver failure both associated with a high morbidity and mortality and sparse therapeutic options other than transplantation. Mononuclear phagocytes play a central role in innate immune responses and represent a first line of defence against pathogens. Their function includes phagocytosis, killing of bacteria, antigen presentation, cytokine production as well as recruitment and activation of immune effector cells. Liver injury and development of cirrhosis induces activation of liver resident Kupffer cells and recruitment of monocytes to the liver. Damage- and pathogen-associated molecular patterns promote systemic inflammation which involves multiple compartments besides the liver, such as the circulation, gut, peritoneal cavity and others. The function of circulating monocytes and tissue macrophages is severely impaired and worsens along with cirrhosis progression. The underlying mechanisms are complex and incompletely understood. Recent 'omics' technologies help to transform our understanding of cellular diversity and function in health and disease. In this review we point out the current state of knowledge on phenotypical and functional changes of monocytes and macrophages during cirrhosis evolution in different compartments and their role in disease progression. We also discuss the value of potential prognostic markers for cirrhosis-associated immuneparesis, and future immunotherapeutic strategies that may reduce the need for transplantation and death.

The Hepatoprotective Effect of Leonurine Hydrochloride Against Alcoholic Liver Disease Based on Transcriptomic and Metabolomic Analysis

Excessive alcohol consumption can eventually progress to alcoholic liver disease (ALD). The underlying mechanism of ALD toxicity is primarily associated with oxidative damage. Many alkaloids have been reported to possess potential antioxidative efficacy, while the mechanism of their hepatoprotective activity against ALD is still not clear. In this study, eight alkaloids were selected from a monomer library of Traditional Chinese Medicine and evaluated for their antioxidant activity against ALD by the evaluation of Glutathione (GSH) and Malondialdehyde (MDA). The result suggested that Leonurine hydrochloride (LH) was a potent antioxidant that could reduce alcoholic liver damage. To further investigate the underlying mechanism of LH against ALD, the molecular pathway induced by LH was identified by RNA-seq analyses. Transcriptome data revealed the principal mechanism for the protective effect of LH against ALD might be attributed to the differentially expressed genes (DEGs) of PI3K-AKT, AMPK, and HIF-1 signaling pathways involved in the lipid metabolism. Given the hepatoprotective mechanism of LH is involved in lipid metabolism, the lipid metabolism induced by LH was further analyzed by UHPLC-MS/MS. Metabolome analysis indicated that LH significantly regulated glycerophospholipid metabolism including phosphatidylcholine, 1-acyl-sn-glycero-3-phosphocholine, phosphatidylethanolamine and 1-acyl-sn-glycero-3-phosphoethanolamine in the liver. Overall, this study revealed that the hepatoprotective mechanism of LH against alcoholic liver damage might be associated with the genes involved in glycerophospholipid metabolism.

TRPV6 channel mediates alcohol-induced gut barrier dysfunction and systemic response

Intestinal epithelial tight junction disruption is a primary contributing factor in alcohol-associated endotoxemia, systemic inflammation, and multiple organ damage. Ethanol and acetaldehyde disrupt tight junctions by elevating intracellular Ca²⁺. Here we identify TRPV6, a Ca²⁺-permeable channel, as responsible for alcohol-induced elevation of intracellular Ca²⁺, intestinal barrier dysfunction, and systemic inflammation. Ethanol and acetaldehyde elicit TRPV6 ionic currents in Caco-2 cells. Studies in Caco-2 cell monolayers and mouse intestinal organoids show that TRPV6 deficiency or inhibition attenuates ethanol- and acetaldehyde-induced Ca²⁺ influx, tight junction disruption, and barrier dysfunction. Moreover, Trpv6^−/− mice are resistant to alcohol-induced intestinal barrier dysfunction. Photoaffinity labeling of 3-azibutanol identifies a histidine as a potential alcohol-binding site in TRPV6. The substitution of this histidine, and a nearby arginine, reduces ethanol-activated currents. Our findings reveal that TRPV6 is required for alcohol-induced gut barrier dysfunction and inflammation. Molecules that decrease TRPV6 function have the potential to attenuate alcohol-associated tissue injury.

Meena et al. show that the mechanism of alcohol-induced gut permeability, endotoxemia, and systemic inflammation requires the TRPV6 channel. They show that ethanol activates TRPV6, induces calcium influx, and disrupts intestinal epithelial tight junctions. Furthermore, specific histidine and arginine residues at the N terminus fine-tune the alcohol-induced activation of TRPV6.

Non-Alcoholic Components in Huangjiu as Potential Factors Regulating the Intestinal Barrier and Gut Microbiota in Mouse Model of Alcoholic Liver Injury

Different alcoholic beverages and drinking patterns might exert divergent impacts on alcoholic liver disease (ALD) progression. Whether the abundant non-alcoholic components (NAC) in fermented wine could alleviate ethanol (EtOH)-induced adverse influences on the liver remains unknown. Hence, the chronic ALD mouse model was established to compare the effects of Huangjiu (a typical fermented wine) and EtOH feeding on the liver, intestinal barrier, gut microbiota, and intestinal short-chain fatty acids (SCFAs) content. Although Huangjiu intake led to slight hepatic steatosis, it mitigated oxidative stress, inflammation, and intestinal damage relative to EtOH intake. In comparison with EtOH feeding, Huangjiu significantly improved the intestinal barrier integrity and reduced hepatic lipopolysaccharide levels by up-regulating the expression of intestinal tight junction proteins (ZO-1 and occludin) and antimicrobial activity peptides (Reg3β and Reg3γ). The administration of Huangjiu NAC partially restored alcohol-induced gut microbiota dysbiosis via recovering the abundance of Lactobacillus, Faecalibaculum, and Akkermansia. Moreover, mice receiving Huangjiu showed higher SCFAs levels (such as acetic acid and butyric acid) than those receiving EtOH. Huangjiu consumption resulted in lower hepatotoxicity than pure EtOH, at the same alcohol dose. The NAC in Huangjiu might attenuate the progression of ALD by regulating intestinal barrier function and microbiota-meditated gut ecology.