The gut-liver axis and gut microbiota in health and liver disease

Comparative genomic and metabolomic analysis reveals the potential of a newly isolated Enterococcus faecium B6 involved in lipogenic effects

Evidence has indicated that Enterococcus plays a vital role in non-alcoholic fatty liver disease (NAFLD) development. However, the microbial genetic basis and metabolic potential in the disease are yet unknown. We previously isolated a bacteria Enterococcus faecium B6 (E. faecium B6) from children with NAFLD for the first time. Here, we aim to systematically investigate the potential of strain B6 in lipogenic effects. The lipogenic effects of strain B6 were explored in vitro and in vivo. The genomic and functional characterizations were investigated by whole-genome sequencing and comparative genomic analysis. Moreover, the metabolite profiles were unraveled by an untargeted metabolomic analysis. We demonstrated that strain B6 could effectively induce lipogenic effects in the liver of mice. Strain B6 contained a circular chromosome and two circular plasmids and posed various functions. Compared to the other two probiotic strains of E. faecium, strain B6 exhibited unique functions in pathways of ABC transporters, phosphotransferase system, and amino sugar and nucleotide sugar metabolism. Moreover, strain B6 produced several metabolites, mainly enriched in the protein digestion and absorption pathway. The unique potential of strain B6 in lipogenic effects was probably associated with glycolysis, fatty acid synthesis, and glutamine and choline transport. This study pioneeringly revealed the metabolic characteristics and specific detrimental traits of strain B6. The findings provided new insights into the underlying mechanisms of E. faecium in lipogenic effects, and laid essential foundations for further understanding of E. faecium-related disease.

Gut Microbiota and Liver Regeneration: A Synthesis of Evidence on Structural Changes and Physiological Mechanisms

Liver regeneration (LR) is a unique biological process with the ability to restore up to 70% of the organ. This allows for the preservation of liver resections for various liver tumors and for living donor liver transplantation (LDLT). However, in some cases, LR is insufficient and interventions that can improve LR are urgently needed. Gut microbiota (GM) is one of the factors influencing LR, as the liver and intestine are intimately connected through the gut-liver axis. Thus, healthy GM facilitates normal LR, whereas dysbiosis leads to impaired LR due to imbalance of bile acids, inflammatory cytokines, microbial metabolites, signaling pathways, etc. Therefore, GM can be considered as a new possible therapeutic target to improve LR. In this review, we critically observe the current knowledge about the influence of gut microbiota (GM) on liver regeneration (LR) and the possibility to improve this process, which may reduce complication and mortality rates after liver surgery. Although much research has been done on this topic, more clinical trials and systemic reviews are urgently needed to move this type of intervention from the experimental phase to the clinical field.

Comprehensive multi-omics investigation of sub-chronic toxicity induced by Cadmium and Triazophos Co-exposure in hook snout carps (Opsariichthys bidens)

The coexistence of heavy metals and pesticides poses a critical challenge in agricultural ecosystems. Traditional toxicity assessments often focus only on the individual impacts of either pesticides or heavy metals. Here, the untargeted metabolomics and 16 S rRNA sequencing were used to assess the individual and combined effects of cadmium (Cd) and triazophos (TRI) on hook snout carps (Opsariichthys bidens). Cd caused much more serious impacts on hepatic metabolism and gut microbiota than those in TRI. Combined Cd and TRI exposure synergistically affected hepatic metabolism, causing mitochondrial dysfunction and even oxidative damage. Simultaneously, 16 S rRNA sequencing highlighted significant variations in the composition and abundance of gut microbiota. A noteworthy connection emerged between these distinct microbiota profiles and disruptions in energy metabolism, ultimately leading to disorders in metabolites. These findings enhanced the understanding of risks posed by heavy metals and pesticides, providing insights for better environmental risk assessments of aquatic organisms.

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.

Dietary dicarbonyl compounds exacerbated immune dysfunction and hepatic oxidative stress under high-fat diets in vivo

High-fat diets (HFDs) predispose to obesity and liver dysfunctions, and α-dicarbonyl compounds (α-DCs) present in highly processed foods are also implicated in relevant pathological processes. However, the synergistic harmful effects of α-DCs co-administered with HFDs remain to be elucidated. In this study, 6-week-old C57BL/6 mice were fed with a HFD co-administered with 0.5% methylglyoxal (MGO)/glyoxal (GO) in water for 8 weeks, and multi-omics approaches were employed to investigate the underlying toxicity mechanisms. The results demonstrated that the MGO intervention with a HFD led to an increased body weight and blood glucose level, accompanied by the biological accumulation of α-DCs and carboxymethyl-lysine, as well as elevated serum levels of inflammatory markers including IL-1β, IL-6, and MIP-1α. Notably, hepatic lesions were observed in the MGO group under HFD conditions, concomitant with elevated levels of malondialdehyde. Transcriptomic analysis revealed enrichment of pathways and differentially expressed genes (DEGs) associated with inflammation and oxidative stress in the liver. Furthermore, α-DC intervention exacerbated gut microbial dysbiosis in the context of a HFD, and through Spearman correlation analysis, the dominant genera such as Fusobacterium and Bacteroides in the MGO group and Colidextribacter and Parabacteroides in the GO group were significantly correlated with a set of DEGs involved in inflammatory and oxidative stress pathways in the liver. This study provides novel insights into the healthy implications of dietary ultra-processed food products in the context of obesity-associated disorders.

Silymarin decreases liver stiffness associated with gut microbiota in patients with metabolic dysfunction-associated steatotic liver disease: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Despite centuries of traditional use of silymarin for hepatoprotection, current randomized controlled trial (RCT) studies on the effectiveness of silymarin in managing metabolic dysfunction-associated steatotic liver disease (MASLD) are limited and inconclusive, particularly when it is administered alone. The low bioavailability of silymarin highlights the possible influence of gut microbiota on the effectiveness of silymarin; however, no human studies have investigated this aspect.

OBJECTIVE

To determine the potential efficacy of silymarin in improving MASLD indicators and to investigate the underlying mechanisms related to gut microbiota.

METHOD

In this 24-week randomized, double-blind, placebo-controlled trial, 83 patients with MASLD were randomized to either placebo (n = 41) or silymarin (103.2 mg/d, n = 42). At 0, 12, and 24 weeks, liver stiffness and hepatic steatosis were assessed using FibroScan, and blood samples were gathered for biochemical detection, while faecal samples were collected at 0 and 24 weeks for 16S rRNA sequencing.

RESULTS

Silymarin supplementation significantly reduced liver stiffness (LSM, -0.21 ± 0.17 vs. 0.41 ± 0.17, P = 0.015) and serum levels of γ-glutamyl transpeptidase (GGT, -8.21 ± 3.01 vs. 1.23 ± 3.16, P = 0.042) and ApoB (-0.02 ± 0.03 vs. 0.07 ± 0.03, P = 0.023) but had no significant effect on the controlled attenuation parameter (CAP), other biochemical indicators (aminotransferases, total bilirubin, glucose and lipid parameters, hsCRP, SOD, and UA), physical measurements (DBP, SBP, BMI, WHR, BF%, and BMR), or APRI and FIB-4 indices. Gut microbiota analysis revealed increased species diversity and enrichment of Oscillospiraceae in the silymarin group.

CONCLUSION

These findings suggest that silymarin supplementation could improve liver stiffness in MASLD patients, possibly by modulating the gut microbiota.

TRIAL REGISTRATION

The trial was registered at the Chinese Clinical Trial Registry (ChiCTR2200059043).

Applications of polysaccharides in enzyme-triggered oral colon-specific drug delivery systems: A review

Enzyme-triggered oral colon-specific drug delivery system (EtOCDDS1) can withstand the harsh stomach and small intestine environments, releasing encapsulated drugs selectively in the colon in response to colonic microflora, exerting local or systematic therapeutic effects. EtOCDDS boasts high colon targetability, enhanced drug bioavailability, and reduced systemic side effects. Polysaccharides are extensively used in enzyme-triggered oral colon-specific drug delivery systems, and its colon targetability has been widely confirmed, as their properties meet the demand of EtOCDDS. Polysaccharides, known for their high safety and excellent biocompatibility, feature modifiable structures. Some remain undigested in the stomach and small intestine, whether in their natural state or after modifications, and are exclusively broken down by colon-resident microbiota. Such characteristics make them ideal materials for EtOCDDS. This article reviews the design principles of EtOCDDS as well as commonly used polysaccharides and their characteristics, modifications, applications and specific mechanism for colon targeting. The article concludes by summarizing the limitations and potential of ETOCDDS to stimulate the development of innovative design approaches.

Gut mycobiome alterations and implications for liver diseases

Chronic liver disease and its complications are a significant global health burden. Changes in fungal communities (mycobiome), an integral component of the gut microbiome, are associated with and contribute to the development of liver disease. Fungal dysbiosis can induce intestinal barrier dysfunction and allow fungal products to translocate to the liver causing progression of disease. This review explores recent progress in understanding the compositional and functional diversity of gut mycobiome signatures across different liver diseases. It delves into causative connections between gut fungi and liver diseases. We emphasize the significance of fungal translocation, with a particular focus on fungal-derived metabolites and immune cells induced by fungi, as key contributors to liver disease. Furthermore, we review the potential impact of the intrahepatic mycobiome on the progression of liver diseases.

Clinical improvement effect of regulating gut microbiota on metabolic dysfunction-associated steatotic liver disease: Systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is constantly rising globally. There are barely any effective medications or supplements for the management of MASLD. We aim to systematically evaluate the most current evidence for gut microbiota-regulating supplements in patients with MASLD.

METHODS

We searched multiple electronic data for randomized controlled trials (RCTs) published from January 1, 2012, to July 15, 2023. The intervention measures included probiotics, prebiotics, synbiotics, antibiotics, and fecal microbiota transplantation (FMT). The control group was treated with a placebo or usual care. The intervention duration was divided into two periods (>12 weeks and ≤12 weeks). Adequate evaluation data for antibiotics and FMT have not been obtained. Therefore, the other three microbiota regulators are the primary evaluation measures in this study.

RESULTS

We found that probiotics alone could not improve clinical indicators in MASLD patients. However, synbiotics exhibited an improvement in reducing liver steatosis, TNF-ɑ levels, and increasing HDL-c levels, and the inflammatory markers of liver cells (ALT and AST) were also improved. For the effective intervention duration, this systematic review suggested that around 12 weeks is an ideal intervention cycle for MASLD patients.

CONCLUSIONS

This meta-analysis supported the modulation of gut microbiota with synbiotics in the management of MASLD.

Folic acid supplementation is associated with a decreased mortality and reduced hospital readmission in patients with decompensated alcohol-related liver cirrhosis

BACKGROUND AND AIMS

Thiamine and folic acid malnutrition is highly frequent in patients with decompensated alcohol-related liver cirrhosis (aLC). Current guidelines therefore recommend vitamin supplementation in these patients. However, implementation and its impact on the clinical outcome remains unknown. Therefore, we aimed to analyze the use of thiamine and folic acid and their effects on mortality and morbidity in patients with decompensated aLC.

METHODS

A number of 289 consecutive patients with decompensated aLC who received a paracentesis at Hannover Medical School between 2011 and 2023 were retrospectively investigated. The use of folic acid and thiamine-containing supplements was assessed in the discharge medication. Patients were followed for up to one year regarding liver transplant (LTx)-free survival and the incidence of hepatic encephalopathy, infections and hepatic decompensation requiring rehospitalization.

RESULTS

Median baseline MELD was 15, median age 56.6 years. 73.0% (n = 211) were male patients. At hospital discharge, thiamine-containing supplements and folic acid were prescribed to 48.1% (n = 139) and 18.0% (n = 52) patients, respectively. Neither thiamine nor folic acid prescription were linked to improved clinical outcomes within 90 days. However, folic acid intake was associated with a higher one-year LTx-free survival (HR = 0.48; p = 0.04) in the multivariable analysis. Furthermore, folic acid substitution was linked to a decreased risk of rehospitalization within one year (HR = 0.55; p = 0.01) in the multivariable competing risk model. In contrast, thiamine prescription did neither affect LTx-free survival nor the here investigated liver-related complications.

CONCLUSION

Folic acid, but not thiamine substitution was linked to an improved outcome in patients with decompensated aLC.

Haematococcus pluvialis polysaccharides improve microbiota-driven gut epithelial and vascular barrier and prevent alcoholic steatohepatitis development

Algal polysaccharides possess many biological activities and health benefits, such as antioxidant, anti-tumor, anti-coagulant, and immunomodulatory potential. Gut microbiota has emerged as one of the major contributor in mediating the health benefits of algal polysaccharides. In this study we showed that Haematococcus pluvialis polysaccharides (HPP) decreased serum transaminase levels and hepatic triglyceride content, alleviated inflammation and oxidative stress in the liver of chronic and binge ethanol diet-fed mice. Furthermore, HPP reduced endotoxemia, improved gut microbiota dysbiosis, inhibited epithelial barrier disruption and gut vascular barrier (GVB) damage in ethanol diet-fed mice. Co-housing vehicle-fed mice with HPP-fed mice alleviated ethanol-induced liver damage and endotoxemia. Moreover, fecal microbiota transplantation from HPP-fed mice into antibiotic-induced microbiota-depleted recipients also alleviated ethanol-induced liver injury and improved gut epithelial and vascular barrier. Our study demonstrated that HPP ameliorated ethanol-induced gut epithelial and vascular barrier dysfunction through alteration of gut microbiota, therefore preventing alcoholic liver damage.

Serum aryl hydrocarbon receptor activity is associated with survival in patients with alcohol-associated hepatitis

BACKGROUND AND AIMS

Patients with alcohol-associated hepatitis (AH) have an altered fecal metabolome, including reduced microbiota-derived tryptophan metabolites, which function as ligands for aryl hydrocarbon receptor (AhR). The aim of this study was to assess serum AhR ligand activity in patients with AH.

APPROACH AND RESULTS

The study included 74 controls without AUD, 97 patients with AUD, and 330 patients with AH from 2 different multicenter cohorts (InTeam: 134, AlcHepNet: 196). Serum AhR activity was evaluated using an AhR reporter assay with HepG2-Lucia cells incubated with serum for 24 hours. Serum AhR activity was significantly higher in patients with AH compared with both controls (1.59 vs. 0.96-fold change, p < 0.001) and patients with AUD (1.59 vs. 0.93, p < 0.001). In both AH cohorts, patients with AhR activity ≥ 2.09 had significantly lower cumulative survival rates at 30, 60, 90, and 180 days compared to those with AhR activity < 2.09. When serum AhR activity was used to further stratify patients with severe AH, the cumulative 30, 60, 90, and 180-day survival rates for patients with severe AH and the AhR activity ≥ 2.09 group were all significantly lower than those with an AhR activity < 2.09 group.

CONCLUSIONS

Serum AhR activity was significantly higher in patients with AH compared with controls and individuals with AUD, and this increased activity was associated with higher mortality. Consequently, serum AhR activity holds potential as a prognostic marker.

Endogenous ethanol production in health and disease

The gut microbiome exerts metabolic actions on distal tissues and organs outside the intestine, partly through microbial metabolites that diffuse into the circulation. The disruption of gut homeostasis results in changes to microbial metabolites, and more than half of the variance in the plasma metabolome can be explained by the gut microbiome. Ethanol is a major microbial metabolite that is produced in the intestine of nearly all individuals; however, elevated ethanol production is associated with pathological conditions such as metabolic dysfunction-associated steatotic liver disease and auto-brewery syndrome, in which the liver's capacity to metabolize ethanol is surpassed. In this Review, we describe the mechanisms underlying excessive ethanol production in the gut and the role of ethanol catabolism in mediating pathogenic effects of ethanol on the liver and host metabolism. We conclude by discussing approaches to target excessive ethanol production by gut bacteria.

Exploring the impact of gut microbiota on liver health in mice and patients with Wilson disease

BACKGROUND AND AIMS

Distinctive gut microbial profiles have been observed between patients with Wilson disease (WD) and healthy individuals. Despite this, the exact relationship and influence of gut microbiota on the advancement of WD-related liver damage remain ambiguous. This research seeks to clarify the gut microbiota characteristics in both human patients and mouse models of WD, as well as their impact on liver injury.

METHODS

Gut microbial features in healthy individuals, patients with WD, healthy mice and mice with early- and late-stage WD were analysed using 16S rRNA gene sequencing. Additionally, WD-afflicted mice underwent treatment with either an antibiotic cocktail (with normal saline as a control) or healthy microbiota (using disease microbiota as a control). The study assessed gut microbiota composition, hepatic transcriptome profiles, liver copper concentrations and hepatic pathological injuries.

RESULTS

Patients with hepatic WD and mice with WD-related liver injury displayed altered gut microbiota composition, notably with a significant reduction in Lactobacillus abundance. Additionally, the abundances of several gut genera, including Lactobacillus, Veillonella and Eubacterium coprostanoligenes, showed significant correlations with the severity of liver injury in patients with WD. In WD mice, antibiotic treatment or transplantation of healthy microbiota altered the gut microbial structure, increased Lactobacillus abundance and modified the hepatic transcriptional profile. These interventions resulted in reduced hepatic copper concentration and alleviation of WD-related liver injury.

CONCLUSIONS

Individuals and mice with pronounced WD-related liver injury exhibited shifts in gut microbial composition. Regulating gut microbiota through healthy microbiota transplantation emerges as a promising therapeutic approach for treating WD-related liver injury.

Christensenella minuta Alleviates Acetaminophen-Induced Hepatotoxicity by Regulating Phenylalanine Metabolism

Acetaminophen (APAP)-induced liver injury (AILI), even liver failure, is a significant challenge due to the limited availability of therapeutic medicine. Christensenella minuta (C. minuta), as a probiotic therapy, has shown promising prospects in metabolism and inflammatory diseases. Our research aimed to examine the influence of C. minuta on AILI and explore the molecular pathways underlying it. We found that administration of C. minuta remarkably alleviated AILI in a mouse model, as evidenced by decreased levels of alanine transaminase (ALT) and aspartate aminotransferase (AST) and improvements in the histopathological features of liver sections. Additionally, there was a notable decrease in malondialdehyde (MDA), accompanied by restoration of the reduced glutathione/oxidized glutathione (GSH/GSSG) balance, and superoxide dismutase (SOD) activity. Furthermore, there was a significant reduction in inflammatory markers (IL6, IL1β, TNF-α). C. minuta regulated phenylalanine metabolism. No significant difference in intestinal permeability was observed in either the model group or the treatment group. High levels of phenylalanine aggravated liver damage, which may be linked to phenylalanine-induced dysbiosis and dysregulation in cytochrome P450 metabolism, sphingolipid metabolism, the PI3K-AKT pathway, and the Integrin pathway. Furthermore, C. minuta restored the diversity of the microbiota, modulated metabolic pathways and MAPK pathway. Overall, this research demonstrates that supplementing with C. minuta offers both preventive and remedial benefits against AILI by modulating the gut microbiota, phenylalanine metabolism, oxidative stress, and the MAPK pathway, with high phenylalanine supplementation being identified as a risk factor exacerbating liver injury.

Liver Fibrosis: From Basic Science towards Clinical Progress, Focusing on the Central Role of Hepatic Stellate Cells

The burden of chronic liver disease is globally increasing at an alarming rate. Chronic liver injury leads to liver inflammation and fibrosis (LF) as critical determinants of long-term outcomes such as cirrhosis, liver cancer, and mortality. LF is a wound-healing process characterized by excessive deposition of extracellular matrix (ECM) proteins due to the activation of hepatic stellate cells (HSCs). In the healthy liver, quiescent HSCs metabolize and store retinoids. Upon fibrogenic activation, quiescent HSCs transdifferentiate into myofibroblasts; lose their vitamin A; upregulate α-smooth muscle actin; and produce proinflammatory soluble mediators, collagens, and inhibitors of ECM degradation. Activated HSCs are the main effector cells during hepatic fibrogenesis. In addition, the accumulation and activation of profibrogenic macrophages in response to hepatocyte death play a critical role in the initiation of HSC activation and survival. The main source of myofibroblasts is resident HSCs. Activated HSCs migrate to the site of active fibrogenesis to initiate the formation of a fibrous scar. Single-cell technologies revealed that quiescent HSCs are highly homogenous, while activated HSCs/myofibroblasts are much more heterogeneous. The complex process of inflammation results from the response of various hepatic cells to hepatocellular death and inflammatory signals related to intrahepatic injury pathways or extrahepatic mediators. Inflammatory processes modulate fibrogenesis by activating HSCs and, in turn, drive immune mechanisms via cytokines and chemokines. Increasing evidence also suggests that cellular stress responses contribute to fibrogenesis. Recent data demonstrated that LF can revert even at advanced stages of cirrhosis if the underlying cause is eliminated, which inhibits the inflammatory and profibrogenic cells. However, despite numerous clinical studies on plausible drug candidates, an approved antifibrotic therapy still remains elusive. This state-of-the-art review presents cellular and molecular mechanisms involved in hepatic fibrogenesis and its resolution, as well as comprehensively discusses the drivers linking liver injury to chronic liver inflammation and LF.

Hepatoprotective potential of four fruit extracts rich in different structural flavonoids against alcohol-induced liver injury via gut microbiota-liver axis

Alcoholic liver injury (ALI) accounts for a major share of the global burden of non-viral liver disease. In the absence of specialized medications, research on using fruit flavonoids as a treatment is gaining momentum. This study investigated the hepatoprotective effects of four fruits rich in structurally diverse flavonoids: ougan (Citrus reticulata cv. Suavissima, OG), mulberry (Morus alba L., MB), apple (Malus × domestica Borkh., AP), and turnjujube (Hovenia dulcis Thunnb., TJ). A total of one flavanone glycoside, three polymethoxyflavones, two anthocyanins, one flavonol glycoside, and one dihydroflavonol were identified through UPLC analysis. In an acute ethanol-induced ALI mouse model, C57BL/6J mice were supplemented with 200 mg/kg·BW/day of different fruit extracts for three weeks. Our results showed that the four extracts exhibited promising benefits in improving lipid metabolism disorders, iron overload, and oxidative stress. RT-PCR and Western blot tests suggested that the potential mechanism may partially be attributed to the activation of the NRF2-mediated antioxidant response and the inhibition of ferroptosis pathways. Furthermore, fruit extracts administration demonstrated a specific regulatory role in intestinal microecology, with increases in beneficial bacteria such as Dubosiella, Lactobacillus, and Bifidobacterium. Spearman correlation analysis revealed strong links between intestinal flora, lipid metabolism, and iron homeostasis, implying that the fruit extracts mitigated ALI via the gut microbiota-liver axis. In vitro experiments reaffirmed the activity against ethanol-induced oxidative damage and highlighted the positive effects of flavonoid components. These findings endorse the prospective application of OG, MB, AP, and TJ as dietary supplements or novel treatments for ALI.

Dynamic changes of gut microbiota in mouse models of metabolic dysfunction-associated steatohepatitis and its transition to hepatocellular carcinoma

Dysbiosis of gut microbiota may account for pathobiology in simple fatty liver (SFL), metabolic dysfunction-associated steatohepatitis (MASH), fibrotic progression, and transformation to MASH-associated hepatocellular carcinoma (MASH-HCC). The aim of the present study is to investigate gut dysbiosis in this progression. Fecal microbial rRNA-16S sequencing, absolute quantification, histopathologic, and biochemical tests were performed in mice fed high fat/calorie diet plus high fructose and glucose in drinking water (HFCD-HF/G) or control diet (CD) for 2, 16 weeks, or 14 months. Histopathologic examination verified an early stage of SFL, MASH, fibrotic, or MASH-HCC progression with disturbance of lipid metabolism, liver injury, and impaired gut mucosal barrier as indicated by loss of occludin in ileum mucosa. Gut dysbiosis occurred as early as 2 weeks with reduced α diversity, expansion of Kineothrix, Lactococcus, Akkermansia; and shrinkage in Bifidobacterium, Lactobacillus, etc., at a genus level. Dysbiosis was found as early as MAHS initiation, and was much more profound through the MASH-fibrotic and oncogenic progression. Moreover, the expansion of specific species, such as Lactobacillus johnsonii and Kineothrix alysoides, was confirmed by an optimized method for absolute quantification. Dynamic alterations of gut microbiota were characterized in three stages of early SFL, MASH, and its HCC transformation. The findings suggest that the extent of dysbiosis was accompanied with MASH progression and its transformation to HCC, and the shrinking or emerging of specific microbial species may account at least in part for pathologic, metabolic, and immunologic alterations in fibrogenic progression and malignant transition in the liver.

Isolation of Bacillus licheniformis and its protective effect on liver oxidative stress and apoptosis induced by aflatoxin B1

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins. The use of probiotics is an effective approach to reduce aflatoxins content in foods. To find efficient bacterial species that can eliminate or detoxify AFB1, a bacterial strain S51 capable of degrading AFB1 was isolated from chicken intestine and soil samples by using a culture medium containing coumarin as the sole carbon source. Based on the results of 16S rRNA gene sequence analysis, this isolate (strain S51) was identified as Bacillus licheniformis strain QT338. Further characterization of strain S51 showed that it could degrade AFB1 by 61.3% after incubation at 30°C for 72 h. Additional studies demonstrated that S51 promoted good growth performance of the treated chickens, showed no hemolytic activity, carried few drug resistance genes, and exhibited a certain level of tolerance to acid and bile salts. Furthermore, to verify whether strain S51 exerts a protective effect on AFB1-induced liver injury in chickens and to elucidate the underlying mechanism, a chicken toxicity model was induced with AFB1 (100 μg/kg BW) and treated with S51(1×109CFU/mL) for 12 d. The results showed that S51 decreased the level of alanine transaminase, aspartate transaminase, and total bilirubin (P < 0.05); increased glutathione activity and total antioxidant capacityin the liver induced by AFB1, and decreased malondialdehyde production (P < 0.05). S51 also up-regulated the mRNA expression level of the antioxidant proteins HO-1 and Nrf2 and down-regulated the expression of the oxidation-related factor Keap1 in the Nrf2/Keap1 signaling pathway (P <0.05). S51 inhibited hepatocyte apoptosis induced by AFB1 and decreased the mRNA expression levels of the apoptosis-related genes Bax, caspase-3, caspase-9, and Cyt-C (P < 0.05). These results indicate that S51 regulates apoptosis and alleviates AFB1-induced oxidative stress in chicken liver by controlling the Nrf2/Keap1 signaling pathway.

Understanding gut dysbiosis for hepatocellular carcinoma diagnosis and treatment

The gut microbiome can play a crucial role in hepatocellular carcinoma (HCC) progression through the enterohepatic circulation, primarily acting via metabolic reprogramming and alterations in the hepatic immune microenvironment triggered by microbe-associated molecular patterns (MAMPs), metabolites, and fungi. In addition, the gut microbiome shows potential as a biomarker for early HCC diagnosis and for assessing the efficacy of immunotherapy in unresectable HCC. This review examines how gut microbiota dysbiosis, with varied functional profiles, contributes to HCCs of different etiologies. We discuss therapeutic strategies to modulate the gut microbiome including diets, antibiotics, probiotics, fecal microbiota transplantation, and nano-delivery systems, and underscore their potential as an adjunctive treatment modality for HCC.

Postbiotics Prepared Using Lactobacillus reuteri Ameliorates Ethanol-Induced Liver Injury by Regulating the FXR/SHP/SREBP-1c Axis

SCOPE

While probiotics-based therapies have exhibited potential in alleviating alcohol-associated liver disease (ALD), the specific role of postbiotics derived from Lactobacillus reuteri (L. reuteri) in ALD remains elusive. This study aims to investigate the impact of postbiotics on ameliorating alcohol-induced hepatic steatosis and the underlying mechanisms.

METHODS AND RESULTS

Using network pharmacology, the study elucidates the targets and pathways impacted by postbiotics from L. reuteri, identifying the farnesoid X receptor (FXR) as a promising target for postbiotics against ALD, and lipid metabolism and alcoholism act as crucial pathways associated with postbiotics-targeting ALD. Furthermore, the study conducts histological and biochemical analyses coupled with LC/MS to evaluate the protective effects and mechanisms of postbiotics against ALD. Postbiotics may modulate bile acid metabolism in vivo by regulating FXR signaling, activating the FXR/FGF15 pathway, and influencing the enterohepatic circulation of bile acids (BAs). Subsequently, postbiotics regulate hepatic FXR activated by BAs and modulate the expression of FXR-mediated protein, including short regulatory partner (SHP) and sterol regulatory element binding protein-1c (SREBP-1c), thereby ameliorating hepatic steatosis in mice with ALD.

CONCLUSION

Postbiotics effectively alleviate ethanol-induced hepatic steatosis by regulating the FXR/SHP/SREBP-1c axis, as rigorously validated in both in vivo and in vitro.

NAFLD/MASLD and the Gut-Liver Axis: From Pathogenesis to Treatment Options

Nonalcoholic fatty liver disease (NAFLD) poses an emerging threat topublic health. Nonalcoholic steatohepatitis (NASH) is reported to be the most rapidly rising cause of hepatocellular carcinoma in the western world. Recently, a new term has been proposed: metabolic dysfunction-associated steatotic liver disease (MASLD). The introduction of this new terminology has sparked a debate about the interchangeability of these terms. The pathogenesis of NAFLD/MASLD is thought to be multifactorial, involving both genetic and environmental factors. Among these factors, alterations in gut microbiota and gut dysbiosis have recently garnered significant attention. In this context, this review will further discuss the gut-liver axis, which refers to the bidirectional interaction between the human gut microbiota and the liver. Additionally, the therapeutic potential of probiotics, particularly next-generation probiotics and genetically engineered bacteria, will be explored. Moreover, the role of prebiotics, synbiotics, postbiotics, and phages as well as fecal microbiota transplantation will be analyzed. Particularly for lean patients with NAFLD/MASLD, who have limited treatment options, approaches that modify the diversity and composition of the gut microbiota may hold promise. However, due to ongoing safety concerns with approaches that modulate gut microbiota, further large-scale studies are necessary to better assess their efficacy and safety in treating NAFLD/MASLD.

Role of liver sinusoidal endothelial cell in metabolic dysfunction-associated fatty liver disease

Liver sinusoidal endothelial cells (LSECs) are highly specialized endothelial cells that represent the interface between blood cells on one side and hepatocytes on the other side. LSECs not only form a barrier within the hepatic sinus, but also play important physiological functions such as regulating hepatic vascular pressure, anti-inflammatory and anti-fibrotic. Pathologically, pathogenic factors can induce LSECs capillarization, that is, loss of fenestra and dysfunction, which are conducive to early steatosis, lay the foundation for the progression of metabolic dysfunction-associated fatty liver disease (MAFLD), and accelerate metabolic dysfunction-associated steatohepatitis (MASH) and liver fibrosis. The unique localization, phenotype, and function of LSECs make them potential candidates for reducing liver injury, inflammation, and preventing or reversing fibrosis in the future.

Importance of the gut microbiota in the gut-liver axis in normal and liver disease

The gut microbiota is of growing interest to clinicians and researchers. This is because there is a growing understanding that the gut microbiota performs many different functions, including involvement in metabolic and immune processes that are systemic in nature. The liver, with its important role in detoxifying and metabolizing products from the gut, is at the forefront of interactions with the gut microbiota. Many details of these interactions are not yet known to clinicians and researchers, but there is growing evidence that normal gut microbiota function is important for liver health. At the same time, factors affecting the gut microbiota, including nutrition or medications, may also have an effect through the gut-liver axis.

The Role of Microbiota-Related Co-Metabolites in MASLD Progression: A Narrative Review

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a growing health concern due to its increasing prevalence worldwide. Metabolic homeostasis encompasses the stable internal conditions vital for efficient metabolism. This equilibrium extends to the intestinal microbiota, whose metabolic activities profoundly influence overall metabolic balance and organ health. The metabolites derived from the gut microbiota metabolism can be defined as microbiota-related co-metabolites. They serve as mediators between the gut microbiota and the host, influencing various physiological processes. The recent redefinition of the term MASLD has highlighted the metabolic dysfunction that characterize the disease. Metabolic dysfunction encompasses a spectrum of abnormalities, including impaired glucose regulation, dyslipidemia, mitochondrial dysfunction, inflammation, and accumulation of toxic byproducts. In addition, MASLD progression has been linked to dysregulation in the gut microbiota and associated co-metabolites. Short-chain fatty acids (SCFAs), hippurate, indole derivatives, branched-chain amino acids (BCAAs), and bile acids (BAs) are among the key co-metabolites implicated in MASLD progression. In this review, we will unravel the relationship between the microbiota-related metabolites which have been associated with MASLD and that could play an important role for developing effective therapeutic interventions for MASLD and related metabolic disorders.

Effects of BBIBP-CorV vaccine on gut microbiota and short-chain fatty acids in mice exposed to bis (2-ethylhexyl) phthalate and dioctyl terephthalate

As the COVID-19 pandemic has progressed, increasing evidences suggest that the gut microbiota may play a crucial role in the effectiveness of SARS-CoV-2 vaccine. Thus, this study was aimed at investigating the influence of SARS-CoV-2 vaccine on the gut microbiota and short-chain fatty acids (SCFAs) of organisms exposed to environmental contaminants, i.e., plasticizers: phthalate esters. We found that in mice, exposure to dioctyl terephthalate (DOTP) and bis -2-ethylhexyl phthalate (DEHP) decreased the blood glucose level and white fat weight, induced inflammatory responses, caused damage to liver and intestinal tissues, and disrupted the gut microbiota composition and SCFAs metabolism. Specifically, the Bacteroidetes phylum was positively correlated with BBIBP-CorV vaccine, while acetic acid was negatively associated with the vaccine. Interestingly, the BBIBP-CorV vaccine somewhat alleviated tissue inflammation and reduced the contents of acetic acid and propionic acid in mice exposed to DEHP and DOTP. These findings were confirmed by a fecal microbiota transplantation assay. Overall, this study revealed that exposure to DEHP and DOTP adversely affects the gut microbiota and SCFAs, while the BBIBP-CorV vaccine can protect mice against these effects. This work highlighted the relationship between BBIBP-CorV vaccination, gut microbiome composition, and responses to plasticizers, which may facilitate the development and risk assessment of SARS-CoV-2 vaccines and environmental contaminants on microbiota health.

Potential of Chlorogenic Acid in the Management of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): Animal Studies and Clinical Trials-A Narrative Review

Chlorogenic acid (CGA) is a natural polyphenol found in coffee, tea, vegetables, and fruits. It exhibits strong antioxidant activity and possesses several other biological properties, including anti-inflammatory effects, antimicrobial activity, and insulin-sensitizing properties. Moreover, it may improve lipid and glucose metabolism. This review summarizes the available information on the therapeutic effect of CGA in metabolic dysfunction-associated steatotic liver disease (MASLD). As the literature search engine, the browsers in the PubMed, Scopus, Web of Science databases, and ClinicalTrials.gov register were used. Animal trials and clinical studies suggest that CGA has promising therapeutic potential in treating MASLD and hepatic steatosis. Its mechanisms of action include antioxidant, anti-inflammatory, and anti-apoptotic effects via the activation of the Nrf2 signaling pathway and the inhibition of the TLR4/NF-κB signaling cascade. Furthermore, the alleviation of liver disease by CGA also involves other important molecules such as AMPK and important physiological processes such as the intestinal barrier and gut microbiota. Nevertheless, the specific target cell and key molecule to which CGA is directed remain unidentified and require further study.

Mechanisms of epigallocatechin gallate (EGCG) in ameliorating hyperuricemia: insights into gut microbiota and intestinal function in a mouse model

Epigallocatechin gallate (EGCG), a prominent bioactive compound found in tea, offers numerous health benefits. Previous studies have highlighted its potential in mitigating hyperuricemia. In this study, hyperuricemic mice induced by potassium oxonate (PO) were treated with EGCG or the anti-hyperuricemia medication allopurinol (AP) to investigate the mechanisms underlying their anti-hyperuricemic effects. The results demonstrated that both EGCG and AP significantly reduced serum uric acid (UA) levels. Further analysis revealed that EGCG promoted the expression of UA secretion transporter genes (Oat1 and Oct1) while inhibiting the expression of UA reabsorption transporter genes (Urat1 and Glut9) in the kidney. By 16S rDNA sequencing, EGCG, but not AP, was found to alter the composition of the gut microbiota. Notably, EGCG induced significant changes in the relative abundance of specific bacteria such as Lactobacillus, Faecalibaculum, and Bifidobacterium, which displayed high correlations with serum UA levels and UA-related gene expression. Metabolomic analysis suggested that EGCG-induced modifications in bacterial metabolites might contribute to the alleviation of hyperuricemia. Transcriptomic analysis of the intestinal epithelium identifies 191 differentially expressed genes (DEGs) in EGCG-treated mice, including 8 purine-related genes. This study elucidates the anti-hyperuricemic mechanisms of EGCG, particularly its influence on the gut microbiota and gene expression in the intestinal epithelium.

Tree peony seed oil alleviates hyperlipidemia and hyperglycemia by modulating gut microbiota and metabolites in high-fat diet mice

With the changes of people's lifestyle, hyperlipidemia and hyperglycemia which were induced from a diet high in both fat and sugar have become serious health concerns. Tree peony seed oil (PSO) is a novel kind of edible oil that shows great potential in the food industry because of its high constituent of unsaturated fatty acids. Based 16S rRNA and gut untargeted metabolomics, this study elucidated that the mechanism of PSO regulating blood glucose (Glu) and lipids. The impact of PSO on gut microbiota balance and gut metabolites of mice with a high-fat diet (HFD) was evaluated. The findings indicated that PSO decreased HFD mice's body weight and fat accumulation, ameliorating the levels of blood lipid, reduced liver fat vacuole levels. What's more PSO modulated the proportion of gut microbiota in HFD mice and enhanced the abundance of probiotics. Furthermore, untargeted metabolomic analysis revealed that PSO not only impacted the generation of short-chain fatty acids (SCFAs) by gut microorganism and altered metabolic pathway but exerted influence on secondary bile acids (BA), amino acid metabolism, and various other metabolites. These results suggested that PSO has the potential function for mitigating HFD-induced hyperlipidemia and hyperglycemia by regulating gut microbiota and host metabolism.

Pleurotus eryngii polysaccharides alleviate aflatoxin B1-induced liver inflammation in ducks involving in remodeling gut microbiota and regulating SCFAs transport via the gut-liver axis

Aflatoxin B1 (AFB1) is one of the most widespread contaminants in agricultural commodities. Pleurotus eryngii (PE) is widely used as a feed additive for its anti-inflammatory properties, and its major active substance is believed to be polysaccharides. This study aims to explore the underlying mechanism of dietary PE polysaccharides alleviating AFB1-induced toxicity in ducks. The major monosaccharide components of PE polysaccharides were identified as glucose, mannose, galactose, glucuronic acid, and fucose. The results showed that dietary PE polysaccharides could alleviate liver inflammation, alleviate intestinal barrier dysfunction, and change the imbalanced gut microbiota induced by AFB1 in ducks. However, PE polysaccharides failed to exert protective roles on the liver and intestine injury induced by AFB1 in antibiotic-treated ducks. The PE + AFB1-originated microbiota showed a positive effect on intestinal barrier and inflammation, the SCFAs transport via the gut-liver axis, and liver inflammation compared with the AFB1-originated microbiota in ducks. These findings provided a possible mechanism that PE polysaccharides alleviated AFB1-induced liver inflammation in ducks by remodeling gut microbiota, regulating microbiota-derived SCFAs transport via the gut-liver axis, and inhibiting inflammatory gene expressions in the liver, which may provide new insight for therapeutic methods against AFB1 exposure in animals.

Fermented dietary fiber from soy sauce residue exerts antidiabetic effects through regulating the PI3K/AKT signaling pathway and gut microbiota-SCFAs-GPRs axis in type 2 diabetic mellitus mice

The gut plays a crucial role in the development and progression of metabolic disorders, particularly in relation to type 2 diabetes mellitus (T2DM). While a high intake of dietary fiber is inversely associated with the risk of T2DM, the specific effects of various dietary fibers on T2DM are not fully understood. This study investigated the anti-diabetic properties of fermented dietary fiber (FDF) derived from soy sauce residue in T2DM mice, demonstrating its ability to lower blood glucose levels and ameliorate insulin resistance. Our findings revealed that FDF could enhance hepatic glucose metabolism via the IRS-1/PI3K/AKT/mTOR pathway. Additionally, the anti-diabetic effect of FDF was correlated with alterations in gut microbiota composition in T2DM mice, promoting a healthier gut environment. Specifically, FDF increased the abundance of beneficial flora such as Dubosiella, Butyricimonas, Lachnospiraceae_NK4A136_group, Lactobacillus and Osillibacter, while reducing harmful bacteria including Bilophila, Parabacteroides and Enterorhabdus. Further analysis of microbial metabolites, including short-chain fatty acids (SCFAs) and bile acids (BAs), provided evidence of FDF's regulatory effects on cecal contents in T2DM mice. Importantly, FDF treatment significantly restored the G-protein-coupled receptors (GPRs) expression in the colon of T2DM mice. In conclusion, our study suggests that the anti-diabetic effects of FDF are associated with the regulation of both the liver-gut axis and the gut microbiota-SCFAs-GPRs axis.

Impact of Transgenerational Nutrition on Nonalcoholic Fatty Liver Disease Development: Interplay between Gut Microbiota, Epigenetics and Immunity

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most prevalent pediatric liver disorder, primarily attributed to dietary shifts in recent years. NAFLD is characterized by the accumulation of lipid species in hepatocytes, leading to liver inflammation that can progress to steatohepatitis, fibrosis, and cirrhosis. Risk factors contributing to NAFLD encompass genetic variations and metabolic disorders such as obesity, diabetes, and insulin resistance. Moreover, transgenerational influences, resulting in an imbalance of gut microbial composition, epigenetic modifications, and dysregulated hepatic immune responses in offspring, play a pivotal role in pediatric NAFLD development. Maternal nutrition shapes the profile of microbiota-derived metabolites in offspring, exerting significant influence on immune system regulation and the development of metabolic syndrome in offspring. In this review, we summarize recent evidence elucidating the intricate interplay between gut microbiota, epigenetics, and immunity in fetuses exposed to maternal nutrition, and its impact on the onset of NAFLD in offspring. Furthermore, potential therapeutic strategies targeting this network are also discussed.

The Potential Mechanism of the Anti-Liver Fibrotic Effect of Curcumin in the Gut-Liver Axis

This study aimed to explore the curative effect of curcumin on liver fibrosis and its correlation with the gut-liver axis in animal models. Histological staining was utilized to conduct histological analysis of the liver and intestine. An automatic biochemical analyzer or enzyme-linked immunosorbent assay system was utilized for analyzing the biochemical indexes in mice. Western blotting was employed to examine the level of relevant proteins. Furthermore, 16S rRNA high-throughput sequencing was performed to explore the impact of curcumin on intestinal microorganisms in rats with liver fibrosis. Ultrahigh-performance liquid chromatography with quadrupole-orbitrap mass spectrometry was utilized to analyze the effect of curcumin on rat feces metabolites. Our results showed that curcumin reduced the formation of collagen fibers caused by carbon tetrachloride in a dose-dependent manner. In addition, curcumin was able to restore intestinal permeability in rats with liver fibrosis. By adopting α diversity analysis (Chao 1 index, Shannon index, and Simpson index), we observed that both the diversity and the abundance of intestinal flora in rats with liver fibrosis were increased. The principal component analysis diagram demonstrated that curcumin could enhance the abundance and diversity of intestinal flora, and also restore the composition of model rat flora, which was similar to that in normal rats, thereby correcting the imbalance of flora in rats with liver fibrosis. In addition, curcumin regulated feces metabolites and their signaling pathways, including glycerophospholipid metabolism, pantothenate and CoA biosynthesis. Our findings suggest that curcumin exhibits antiliver fibrosis effects, and its antiliver fibrosis effects might correlate with gut-liver axis.

Ileitis promotes MASLD progression via bile acid modulation and enhanced TGR5 signaling in ileal CD8+ T cells

BACKGROUND & AIMS

Clinical evidence substantiates a link between inflammatory bowel disease, particularly Crohn's disease (CD), and metabolic dysfunction-associated steatotic liver disease (MASLD). This study aims to explore the underlying molecular mechanisms responsible for this association.

METHODS

MASLD was induced by administering high-fat and western diets, while inflammatory bowel disease was induced using DSS (dextran sulfate sodium) and the Il10 knockout (KO) mouse model. The investigation into the role of secondary bile acids (SBAs) in ileitis involved employing metagenomic sequencing, conducting metabolomics detection, performing fecal microbiota transplantation, and constructing CD8+ T cell-specific gene knockout mice.

RESULTS

In MASLD+DSS and Il10 KO MASLD mice, we observed ileitis characterized by T-cell infiltration and activation in the terminal ileum. This condition resulted in decreased bile acid levels in the portal vein and liver, inhibited hepatic farnesoid X receptor (FXR) activation, and exacerbated MASLD. Metagenomic and metabolomic analysis of ileal contents revealed increased Clostridium proliferation and elevated SBA levels in MASLD-associated ileitis. Experiments using germ-free mice and fecal microbiota transplantation suggested an association between SBA and MASLD-related ileitis. In vitro, SBAs promoted CD8+ T-cell activation via the TGR5, mTOR, and oxidative phosphorylation pathways. In vivo, TGR5 KO in CD8+ T cells effectively alleviated ileitis and reversed the MASLD phenotype. Clinical data further supported these findings, demonstrating a positive correlation between ileitis and MASLD.

CONCLUSION

MASLD-induced changes in intestinal flora result in elevated levels of SBAs in the ileum. In the presence of a compromised intestinal barrier, this leads to severe CD8+ T cell-mediated ileitis through the TGR5/mTOR/oxidative phosphorylation signaling pathway. Ileitis-induced tissue damage impairs enterohepatic circulation, inhibits hepatic FXR activation, and exacerbates the MASLD phenotype.

IMPACT AND IMPLICATIONS

Our study provides a comprehensive investigation of the interplay and underlying mechanisms connecting ileitis and metabolic dysfunction-associated steatotic liver disease (MASLD). Secondary bile acids produced by intestinal bacteria act as the critical link between MASLD and ileitis. Secondary bile acids exert their influence by disrupting liver lipid metabolism through the promotion of CD8+ T cell-mediated ileitis. In future endeavors to prevent and treat MASLD, it is essential to thoroughly account for the impact of the intestinal tract, especially the ileum, on liver function via the enterohepatic circulation.

The role of the microbiome in liver disease

PURPOSE OF REVIEW

The intestinal microbiome and the gut-liver axis play a major role in health and disease. The human gut harbors trillions of microbes and a disruption of the gut homeostasis can contribute to liver disease. In this review, the progress in the field within the last 3 years is summarized, focusing on metabolic dysfunction-associated steatotic liver disease (MASLD), alcohol-associated liver disease (ALD), autoimmune liver disease (AILD), and hepatocellular carcinoma (HCC).

RECENT FINDINGS

Changes in the fecal virome and fungal mycobiome have been described in patients with various liver diseases. Several microbial derived metabolites including endogenous ethanol produced by bacteria, have been mechanistically linked to liver disease such as MASLD. Virulence factors encoded by gut bacteria contribute to ALD, AILD and HCC. Novel therapeutic approaches focused on the microbiome including phages, pre- and postbiotics have been successfully used in preclinical models. Fecal microbiota transplantation has been effective in attenuating liver disease. Probiotics are safe in patients with alcohol-associated hepatitis and improve liver disease and alcohol addiction.

SUMMARY

The gut-liver axis plays a key role in the pathophysiology of liver diseases. Understanding the microbiota in liver disease can help to develop precise microbiota centered therapies.

Overcoming Resistance to Immune Checkpoint Blockade in Liver Cancer with Combination Therapy: Stronger Together?

Primary liver cancer, represented mainly by hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (CCA), is one of the most common and deadliest tumors worldwide. While surgical resection or liver transplantation are the best option in early disease stages, these tumors often present in advanced stages and systemic treatment is required to improve survival time. The emergence of immune checkpoint inhibitor (ICI) therapy has had a positive impact especially on the treatment of advanced cancers, thereby establishing immunotherapy as part of first-line treatment in HCC and CCA. Nevertheless, low response rates reflect on the usually cold or immunosuppressed tumor microenvironment of primary liver cancer. In this review, we aim to summarize mechanisms of resistance leading to tumor immune escape with a special focus on the composition of tumor microenvironment in both HCC and CCA, also reflecting on recent important developments in ICI combination therapy. Furthermore, we discuss how combination of ICIs with established primary liver cancer treatments (e.g. multikinase inhibitors and chemotherapy) as well as more complex combinations with state-of-the-art therapeutic concepts may reshape the tumor microenvironment, leading to higher response rates and long-lasting antitumor immunity for primary liver cancer patients.

Bile acid metabolism and signaling in health and disease: molecular mechanisms and therapeutic targets

Bile acids, once considered mere dietary surfactants, now emerge as critical modulators of macronutrient (lipid, carbohydrate, protein) metabolism and the systemic pro-inflammatory/anti-inflammatory balance. Bile acid metabolism and signaling pathways play a crucial role in protecting against, or if aberrant, inducing cardiometabolic, inflammatory, and neoplastic conditions, strongly influencing health and disease. No curative treatment exists for any bile acid influenced disease, while the most promising and well-developed bile acid therapeutic was recently rejected by the FDA. Here, we provide a bottom-up approach on bile acids, mechanistically explaining their biochemistry, physiology, and pharmacology at canonical and non-canonical receptors. Using this mechanistic model of bile acids, we explain how abnormal bile acid physiology drives disease pathogenesis, emphasizing how ceramide synthesis may serve as a unifying pathogenic feature for cardiometabolic diseases. We provide an in-depth summary on pre-existing bile acid receptor modulators, explain their shortcomings, and propose solutions for how they may be remedied. Lastly, we rationalize novel targets for further translational drug discovery and provide future perspectives. Rather than dismissing bile acid therapeutics due to recent setbacks, we believe that there is immense clinical potential and a high likelihood for the future success of bile acid therapeutics.

Exploring Advanced Therapies for Primary Biliary Cholangitis: Insights from the Gut Microbiota-Bile Acid-Immunity Network

Primary biliary cholangitis (PBC) is a cholestatic liver disease characterized by immune-mediated injury to small bile ducts. Although PBC is an autoimmune disease, the effectiveness of conventional immunosuppressive therapy is disappointing. Nearly 40% of PBC patients do not respond to the first-line drug UDCA. Without appropriate intervention, PBC patients eventually progress to liver cirrhosis and even death. There is an urgent need to develop new therapies. The gut-liver axis emphasizes the interconnection between the gut and the liver, and evidence is increasing that gut microbiota and bile acids play an important role in the pathogenesis of cholestatic diseases. Dysbiosis of gut microbiota, imbalance of bile acids, and immune-mediated bile duct injury constitute the triad of pathophysiology in PBC. Autoimmune cholangitis has the potential to be improved through immune system modulation. Considering the failure of conventional immunotherapies and the involvement of gut microbiota and bile acids in the pathogenesis, targeting immune factors associated with them, such as bile acid receptors, microbial-derived molecules, and related specific immune cells, may offer breakthroughs. Understanding the gut microbiota-bile acid network and related immune dysfunctions in PBC provides a new perspective on therapeutic strategies. Therefore, we summarize the latest advances in research of gut microbiota and bile acids in PBC and, for the first time, explore the possibility of related immune factors as novel immunotherapy targets. This article discusses potential therapeutic approaches focusing on regulating gut microbiota, maintaining bile acid homeostasis, their interactions, and related immune factors.

Isolation of mucosa-associated microbiota dysbiosis in the ascending colon in hepatitis C virus post-sustained virologic response cirrhotic patients

Background

Achieving sustained virologic response (SVR) in patients infected with hepatitis C virus (HCV) reduces all-cause mortality. However, the mechanisms and risk factors for liver fibrosis and portal hypertension post-SVR remain incompletely understood. In the gut-liver axis, mucosa-associated microbiota (MAM) substantially influence immune and metabolic functions, displaying spatial heterogeneity at the anatomical intestinal site. We analyzed MAM composition and function to isolate the locoregional MAM involved in chronic liver disease progression in HCV post-SVR patients.

Methods

We collected MAM samples from three intestinal sites (terminal ileum, ascending colon, and sigmoid colon) via brushing during colonoscopy in 23 HCV post-SVR patients and 25 individuals without liver disease (controls). The 16S rRNA of bacterial DNA in specimens collected with a brush and in feces was sequenced. The molecular expression of intestinal tissues and hepatic tissues were evaluated by quantitative real-time PCR.

Results

In the post-SVR group, the microbial β-diversity of MAM, especially in the ascending colon, differed from the control group and was associated with liver fibrosis progression. In PICRUSt analysis, MAM in the ascending colon in the liver cirrhosis (LC) group showed compromised functions associated with the intestinal barrier and bile acid production, and FGF19 expression was markedly decreased in the terminal ileum biopsy tissue in the LC group. At the genus level, six short-chain fatty acid (SCFA)-producing bacterial genera, Blautia, Alistipes, Roseburia, Agathobaculum, Dorea, and Pseudoflavonifractor were reduced in the ascending colon of post-SVR LC patients.

Conclusion

In patients of HCV post-SVR, we identified the association between the degree of liver fibrosis and dysbiosis of mucosa-associated SCFA-producing bacterial genera that may be related to intestinal barrier and bile acid production in the ascending colon.

The Past and Future of Inflammation as a Target to Cancer Prevention

Inflammation is an essential defense mechanism in which innate immune cells are coordinately activated on encounter of harmful stimuli, including pathogens, tissue injury, and toxic compounds and metabolites to neutralize and eliminate the instigator and initiate healing and regeneration. Properly terminated inflammation is vital to health, but uncontrolled runaway inflammation that becomes chronic begets a variety of inflammatory and metabolic diseases and increases cancer risk. Making damaged tissues behave as "wounds that do not heal" and sustaining the production of growth factors whose physiologic function is tissue healing, chronic inflammation accelerates cancer emergence from premalignant lesions. In 1863, Rudolf Virchow, a leading German pathologist, suggested a possible association between inflammation and tumor formation, but it took another 140 years to fully elucidate and appreciate the tumorigenic role of inflammation. Key findings outlined molecular events in the inflammatory cascade that promote cancer onset and progression and enabled a better appreciation of when and where inflammation should be inhibited. These efforts triggered ongoing research work to discover and develop inflammation-reducing chemopreventive strategies for decreasing cancer risk and incidence.

Microplastic-mediated new mechanism of liver damage: From the perspective of the gut-liver axis

Microplastics (MPs) are environmental contaminants that are present in all environments and can enter the human body, accumulate in various organs, and cause harm through the ingestion of food, inhalation, and dermal contact. The connection between bowel and liver disease and the interplay between gut, liver, and flora has been conceptualized as the "gut-liver axis". Microplastics can alter the structure of microbial communities in the gut and the liver can also be a target for microplastic invasion. Numerous studies have found that when MPs impair human health, they not only promote dysbiosis of the gut microbiota and disruption of the gut barrier but also cause liver damage. For this reason, the gut-liver axis provides a new perspective in understanding this toxic response. The cross-talk between MPs and the gut-liver axis has attracted the attention of the scientific community, but knowledge about whether MPs cause gut-liver interactions through the gut-liver axis is still very limited, and the effect of MPs on liver injury is not well understood. MPs can directly induce microbiota disorders and gut barrier dysfunction. As a result, harmful bacteria and metabolites in the gut enter the blood through the weak intestinal barrier (portal vein channel along the gut-liver axis) and reach the liver, causing liver damage (inflammatory damage, metabolic disorders, oxidative stress, etc.). This review provides an integrated perspective of the gut-liver axis to help conceptualize the mechanisms by which MP exposure induces gut microbiota dysbiosis and hepatic injury and highlights the connection between MPs and the gut-liver axis. Therefore, from the perspective of the gut-liver axis, targeting intestinal flora is an important way to eliminate microplastic liver damage.

From NAFLD to MASLD: implications of the new nomenclature for preclinical and clinical research

Non-alcoholic liver disease (NAFLD) is now metabolic dysfunction-associated steatotic liver disease (MASLD), emphasizing the key metabolic factors of obesity, insulin resistance, vascular dysfunction, and dyslipidemia. Here, we discuss impacts on the existing body of clinical and preclinical liver disease research and research moving forward.

Tangshen formula targets the gut microbiota to treat non-alcoholic fatty liver disease in HFD mice: A 16S rRNA and non-targeted metabolomics analyses

BACKGROUND

Tangshen formula (TSF) has an ameliorative effect on hepatic lipid metabolism in non-alcoholic fatty liver disease (NAFLD), but the role played by the gut microbiota in this process is unknown.

METHOD

We conducted three batches of experiments to explore the role played by the gut microbiota: TSF administration, antibiotic treatment, and fecal microbial transplantation. NAFLD mice were induced with a high-fat diet to investigate the ameliorative effects of TSF on NAFLD features and intestinal barrier function. 16S rRNA sequencing and serum untargeted metabolomics were performed to further investigate the modulatory effects of TSF on the gut microbiota and metabolic dysregulation in the body.

RESULTS

TSF ameliorated insulin resistance, hypercholesterolemia, lipid metabolism disorders, inflammation, and impairment of intestinal barrier function. 16S rRNA sequencing analysis revealed that TSF regulated the composition of the gut microbiota and increased the abundance of beneficial bacteria. Antibiotic treatment and fecal microbiota transplantation confirmed the importance of the gut microbiota in the treatment of NAFLD with TSF. Subsequently, untargeted metabolomics identified 172 differential metabolites due to the treatment of TSF. Functional predictions suggest that metabolisms of choline, glycerophospholipid, linoleic acid, alpha-linolenic acid, and arachidonic acid are the key metabolic pathways by which TSF ameliorates NAFLD and this may be influenced by the gut microbiota.

CONCLUSION

TSF treats the NAFLD phenotype by remodeling the gut microbiota and improving metabolic profile, suggesting that TSF is a functional gut microbial and metabolic modulator for the treatment of NAFLD.

The pathophysiology of MASLD: an immunometabolic perspective

INTRODUCTION

Metabolic-associated liver diseases have emerged pandemically across the globe and are clinically related to metabolic disorders such as obesity and type 2 diabetes. The new nomenclature and definition (i.e. metabolic dysfunction-associated steatotic liver disease - MASLD; metabolic dysfunction-associated steatohepatitis - MASH) reflect the nature of these complex systemic disorders, which are characterized by inflammation, gut dysbiosis and metabolic dysregulation. In this review, we summarize recent advantages in understanding the pathophysiology of MASLD, which we parallel to emerging therapeutic concepts.

AREAS COVERED

We summarize the pathophysiologic concepts of MASLD and its transition to MASH and subsequent advanced sequelae of diseases. Furthermore, we highlight how dietary constituents, microbes and associated metabolites, metabolic perturbations, and immune dysregulation fuel lipotoxicity, hepatic inflammation, liver injury, insulin resistance, and systemic inflammation. Deciphering the intricate pathophysiologic processes that contribute to the development and progression of MASLD is essential to develop targeted therapeutic approaches to combat this escalating burden for health-care systems.

EXPERT OPINION

The rapidly increasing prevalence of metabolic dysfunction-associated steatotic liver disease challenges health-care systems worldwide. Understanding pathophysiologic traits is crucial to improve the prevention and treatment of this disorder and to slow progression into advanced sequelae such as cirrhosis and hepatocellular carcinoma.

Effect of Transarterial Chemotherapy on the Structure and Function of Gut Microbiota in New Zealand White Rabbits

The gut microbiota (GM) are closely related to hepatocellular carcinoma (HCC) occurrence and development. Furthermore, patients with HCC who have received transcatheter arterial chemoembolization (TACE) treatment often experience adverse gastrointestinal reactions, which may be related to changes in the GM caused by the chemotherapeutic drugs used in TACE. Therefore, we conducted animal experiments to investigate these changes. We analyzed changes in the GM of New Zealand white rabbits treated with hepatic arterial chemotherapy by measuring the levels of serological and colonic tissue markers. Simultaneously, we evaluated the correlation between the GM and these markers to explore the mechanism by which chemotherapy affects the GM. Following transarterial chemotherapy with epirubicin, the Firmicutes abundance decreased, whereas that of Proteobacteria increased. The relative abundance of beneficial bacteria, such as Muribaculaceae, Enterococcus, Ruminococcus, and Clostridia, decreased in the experimental group compared with those in the control group. However, the relative abundance of harmful bacteria, such as Bacteroides and Escherichia (Shigella), was higher in the experimental group than in the control group. Following chemotherapy, the GM of rabbits showed a dynamic change over time, first aggravating and then subsiding. The changes were most notable on the fourth day after surgery and recovered slightly on the seventh day. The changes in the host's GM before and after arterial chemotherapy are evident. Hepatic arterial chemotherapy induces dysbiosis of the intestinal microbiota, disrupts intestinal barrier function, damages the integrity of the intestinal mucosa, increases intestinal permeability, facilitates excessive passage of harmful substances through the gut-liver axis communication between the liver and intestine, and triggers activation of inflammatory pathways such as LPS-TLR-4-pSTAT3, ultimately leading to an inflammatory response. This study provides a theoretical basis for combining TACE with targeted GM intervention to treat HCC and reduce adverse gastrointestinal reactions.

Underlying Mechanisms behind the Brain-Gut-Liver Axis and Metabolic-Associated Fatty Liver Disease (MAFLD): An Update

Metabolic-associated fatty liver disease (MAFLD) includes several metabolic dysfunctions caused by dysregulation in the brain-gut-liver axis and, consequently, increases cardiovascular risks and fatty liver dysfunction. In MAFLD, type 2 diabetes mellitus, obesity, and metabolic syndrome are frequently present; these conditions are related to liver lipogenesis and systemic inflammation. This study aimed to review the connection between the brain-gut-liver axis and MAFLD. The inflammatory process, cellular alterations in hepatocytes and stellate cells, hypercaloric diet, and sedentarism aggravate the prognosis of patients with MAFLD. Thus, to understand the modulation of the physiopathology of MAFLD, it is necessary to include the organokines involved in this process (adipokines, myokines, osteokines, and hepatokines) and their clinical relevance to project future perspectives of this condition and bring to light new possibilities in therapeutic approaches. Adipokines are responsible for the activation of distinct cellular signaling in different tissues, such as insulin and pro-inflammatory cytokines, which is important for balancing substances to avoid MAFLD and its progression. Myokines improve the quantity and quality of adipose tissues, contributing to avoiding the development of MAFLD. Finally, hepatokines are decisive in improving or not improving the progression of this disease through the regulation of pro-inflammatory and anti-inflammatory organokines.

Nutritional deficiencies in alcohol use disorder/alcohol-associated liver disease

PURPOSE OF REVIEW

To delineate common and uncommon dietary and nutritional deficiencies in individuals with chronic heavy alcohol use and alcohol use disorder and to highlight important advances in the nutrition field in patients ranging from those with alcohol use disorder (AUD) and no liver disease to those with decompensated alcohol-associated liver disease (ALD).

RECENT FINDINGS

Patients with AUD may have nutritional deficiencies, especially isolated nutrient deficiencies, such as thiamine or zinc deficiencies. This should not be surprising, as alcohol is a major source of "empty calories." It is devoid of critical macronutrients, such as protein, and micronutrients including important vitamins and minerals. Patients with AUD frequently drink much more than often appreciated (10-20 drinks a day). Patients with AUD and early ALD often begin to develop more apparent nutritional deficiencies. Healthcare providers need to be aware of the presenting features of individual nutrient deficiencies, such as thiamine deficiency, and to provide prompt treatment. In patients with more advanced liver disease, malnutrition correlates with severity of liver disease. It is important to understand the value of nutritional support throughout the spectrum of AUD.

SUMMARY

We review nutritional deficiencies in the spectrum of patients with AUD and ALD and highlight new information and recommendations.

Application of Microbiome-Based Therapies in Chronic Respiratory Diseases

The application of microbiome-based therapies in various areas of human disease has recently increased. In chronic respiratory disease, microbiome-based clinical applications are considered compelling options due to the limitations of current treatments. The lung microbiome is ecologically dynamic and affected by various conditions, and dysbiosis is associated with disease severity, exacerbation, and phenotype as well as with chronic respiratory disease endotype. However, it is not easy to directly modulate the lung microbiome. Additionally, studies have shown that chronic respiratory diseases can be improved by modulating gut microbiome and administrating metabolites. Although the composition, diversity, and abundance of the microbiome between the gut and lung are considerably different, modulation of the gut microbiome could improve lung dysbiosis. The gut microbiome influences that of the lung via bacterial-derived components and metabolic degradation products, including short-chain fatty acids. This phenomenon might be associated with the cross-talk between the gut microbiome and lung, called gut-lung axis. There are multiple alternatives to modulate the gut microbiome, such as prebiotics, probiotics, and postbiotics ingestion and fecal material transplantation. Several studies have shown that high-fiber diets, for example, present beneficial effects through the production of short-chain fatty acids. Additionally, genetically modified probiotics to secrete some beneficial molecules might also be utilized to treat chronic respiratory diseases. Further studies on microbial modulation to regulate immunity and potentiate conventional pharmacotherapy will improve microbiome modulation techniques, which will develop as a new therapeutic area in chronic respiratory diseases.

Bacillus coagulans regulates gut microbiota and ameliorates the alcoholic-associated liver disease in mice

Introduction

Alcoholic-associated liver diseases (ALD) are now widespread issues worldwide. Alcoholic-induced chronic dysbiosis of the gut microbiota is one of the factors in the pathophysiology of ALD.

Methods

In this work, we employed a chronic-binge ethanol feeding mice model, as described in a previous report.

Results

Our findings demonstrate that hepatic inflammatory injury damage and accumulation of fat can be effectively reduced in mice with ALD by altering the gut microbiota utilizing Bacillus coagulans. Treatment with B. coagulans significantly modulates the levels of TNF-α, IL-1β, and IL-22 cytokines while maintaining tight junction proteins and mucin protein expressions to support intestinal barrier function restoration. Treatment with B. coagulans also alters the composition of the gut microbiota and increases the production of short-chain fatty acids (SCFAs).

Discussion

This is mostly due to B. coagulans promotes the growth of bacteria that produce SCFAs, such as Ruminococcus species and Akkermansia, while inhibiting the growth of pathogenic bacteria like Escherichia Shigella. Moreover, treatment with B. coagulans causes levels of 2-Ketobutyric acid, ketoleucine, and indoleacetic acid increase while homovanillic acid and 3'-O-Methylguanosine metabolites decrease significantly. This study facilitates the development of therapeutic and preventive strategies for ALD using lactic acid bacteria.