Imbalanced gut microbiota fuels hepatocellular carcinoma development by shaping the hepatic inflammatory microenvironment

Failure of colonization following gut microbiota transfer exacerbates DSS-induced colitis

To study the impact of differing specific pathogen-free gut microbiomes (GMs) on a murine model of inflammatory bowel disease, selected GMs were transferred using embryo transfer (ET), cross-fostering (CF), and co-housing (CH). Prior work showed that the GM transfer method and the microbial composition of donor and recipient GMs can influence microbial colonization and disease phenotypes in dextran sodium sulfate-induced colitis. When a low richness GM was transferred to a recipient with a high richness GM via CH, the donor GM failed to successfully colonize, and a more severe disease phenotype resulted when compared to ET or CF, where colonization was successful. By comparing CH and gastric gavage for fecal material transfer, we isolated the microbial component of this effect and determined that differences in disease severity and survival were associated with microbial factors rather than the transfer method itself. Mice receiving a low richness GM via CH and gastric gavage exhibited greater disease severity and higher expression of pro-inflammatory immune mediators compared to those receiving a high richness GM. This study provides valuable insights into the role of GM composition and colonization in disease modulation.

Investigation of the mechanisms of liver injury induced by emamectin benzoate exposure at environmental concentrations in zebrafish: A multi-omics approach to explore the role of the gut-liver axis

Emamectin benzoate (EMB) is a lipophilic pesticide that enters aquatic systems and adversely affects non-target organisms. This study investigated the long-term effects of EMB on zebrafish, exposing them to concentrations of 0, 0.1, 1, and 10 μg/L from the 4-hour post-fertilization (hpf) embryo stage to the 120-day post-fertilisation (dpf) adult stage. We found that exposure to 1 μg/L EMB induced liver damage, manifested as impaired liver function (elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT)), histopathological damage (lipid accumulation), as well as inflammatory and oxidative damage, with a dose - dependent effect. Non-targeted metabolomic analysis revealed an increase in lipid molecules in the liver, affecting the pathways related to glycerophospholipid metabolism. In addition, EMB exposure resulted in damage to the intestinal barrier and inflammatory responses in zebrafish. 16S rRNA sequencing demonstrated that EMB exposure resulted in notable alterations in the gut microbiota composition. Notably, the abundance of Plesiomonas and Cetobacterium increased in the EMB exposure group and exhibited a positive correlation with the majority of liver lipid metabolites. In contrast, reductions in Muribaculaceae and Alloprevotella were negatively correlated. The results of this study indicate that long-term exposure to EMB disrupts the gut microbiota, leading to the dysregulation of hepatic phospholipid metabolism. These findings provide new insights into the health risks associated with EMB and highlight its potential threats to higher organisms, including mammals.

The important role of myeloid-derived suppressor cells: From hepatitis to liver cancer

Liver homeostasis is coordinated by crosstalk between resident and infiltrating inflammatory cells. Liver disease creates a dynamic inflammatory microenvironment characterized by aberrant metabolism and continuous hepatic regeneration, making it an important risk factor for hepatocellular carcinoma (HCC) as well as liver failure. Recent studies have revealed a critical heterogeneous population of myeloid-derived suppressor cells (MDSCs), which influence liver disease progression and malignancy by dynamically regulating the immune microenvironment. MDSCs play an important role in preventing excessive immune responses in the liver. However, MDSCs are also associated with the promotion of liver injury and liver cancer progression. The plasticity of MDSCs in liver disease is a unique challenge for therapeutic intervention strategies and requires a deeper understanding of the underlying mechanisms. Here, we review the role of MDSCs in the establishment and progression of liver disease and highlight the evidence for MDSCs as a priority target for current and future therapeutic strategies. We explore the fate of MDSCs from hepatitis to liver cancer, providing recent insights into potential targets for clinical intervention.

Study of immunosenescence in the occurrence and immunotherapy of gastrointestinal malignancies

In human beings heterogenous, pervasive and lethal malignancies of different parts of the gastrointestinal (GI) tract viz., tumours of the oesophagus, stomach, small intestine, colon, and rectum, represent gastrointestinal malignancies. Primary treatment modality for gastric cancer includes chemotherapy, surgical interventions, radiotherapy, monoclonal antibodies and inhibitors of angiogenesis. However, there is a need to improve upon the existing treatment modality due to associated adverse events and the development of resistance towards treatment. Additionally, age has been found to contribute to increasing the incidence of tumours due to immunosenescence-associated immunosuppression. Immunosenescence is the natural process of ageing, wherein immune cells as well as organs begin to deteriorate resulting in a dysfunctional or malfunctioning immune system. Accretion of senescent cells in immunosenescence results in the creation of a persistent inflammatory environment or inflammaging, marked with elevated expression of pro-inflammatory and immunosuppressive cytokines and chemokines. Perturbation in the T-cell pools and persistent stimulation by the antigens facilitate premature senility of the immune cells, and senile immune cells exacerbate inflammaging conditions and the inefficiency of the immune system to identify the tumour antigen. Collectively, these conditions contribute positively towards tumour generation, growth and eventually proliferation. Thus, activating the immune cells to distinguish the tumour cells from normal cells and invade them seems to be a logical strategy for the treatment of cancer. Consequently, various approaches to immunotherapy, viz., programmed death ligand-1 (PD-1) inhibitors, Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors etc are being extensively evaluated for their efficiency in gastric cancer. In fact, PD-1 inhibitors have been sanctioned as late late-line therapy modality for gastric cancer. The present review will focus on deciphering the link between the immune system and gastric cancer, and the alterations in the immune system that incur during the development of gastrointestinal malignancies. Also, the mechanism of evasion by tumour cells and immune checkpoints involved along with different approaches of immunotherapy being evaluated in different clinical trials will be discussed.

Microbial characteristics of gut microbiome dysbiosis in patients with chronic liver disease

BACKGROUND

In this study, we are committed to exploring the characteristics of the gut microbiome in three different stages of chronic liver disease (CLD): Chronic hepatitis B, liver cirrhosis, and hepatocellular carcinoma (HCC).

AIM

To delineate the gut microbiota traits in individuals with chronic liver ailments (chronic hepatitis B, cirrhosis, HCC), scrutinizes microbiome alterations during the progression of these diseases, and assesses microbiome disparities among various Child-Pugh categories in cirrhosis sufferers.

METHODS

A cohort of 60 CLD patients from the Third People’s Hospital of Yunnan Province were recruited from February to August 2023, together with 37 healthy counterparts. Employing 16SrDNA high-throughput sequencing, we evaluated the diversity and composition of the gut microbiota.

RESULTS

Compared to healthy subjects, patients exhibited a reduced presence of Firmicutes and a corresponding decline in butyrate-producing genera. In contrast, an upsurge in Proteobacteria was observed in the diseased cohorts, particularly an increase in Enterobacteriaceae that intensified with the disease's progression. At the genus level, the occurrence of Escherichia_Shigella, Parabacteroides, Streptococcus, Klebsiella, and Enterococcus was higher, with Escherichia_Shigella numbers augmenting as the disease advanced. Furthermore, in cirrhosis patients, an increase in Proteobacteria was noted as liver reserve diminished, alongside a decrease in Ruminococcaceae and Bacteroidaceae.

CONCLUSION

The reduced abundance of short-chain fatty acid-producing bacteria in the intestine, alongside the increased abundance of gram-negative bacteria such as Escherichia_Shigella and Parabacteroides, may promote the progression of CLD.

Multi-omics joint analysis: Pachymic acid ameliorated non-alcoholic fatty liver disease by regulating gut microbiota

Poria cocos a traditional Chinese medicinal material with both culinary and therapeutic applications, contains pachymic acid (Pac) as one of its main active compounds, which has demonstrated anti-lipid accumulation and hypoglycemic effects. However, its impact on the biochemical changes in the enterohepatic axis induced by a high-fat diet remains poorly understood. This study investigated the protective mechanism of Pac using a high-fat diet-induced non-alcoholic fatty liver disease (NAFLD) mouse model. 16S rRNA sequencing of gut microbiota revealed that Pac administration reduced the Firmicutes to Bacteroidetes ratio, restored Akkermansia abundance, decreased Desulfovibrio and Streptococcus population, and ameliorated gut dysbiosis. Concurrently, Pac treatment reduced the expression of hepatic inflammatory factors by mainly adjusted LPS/TLR4/MYD88/NFκB pathway. Liver transcriptome analysis indicated that Pac primarily affects genes involved in lipid metabolism, apoptosis, and inflammatory responses. Specifically, Pac inhibited FASN, SREBP1c, and SCD1 expression while upregulating PPARα and CPT1α, thereby improving high-fat diet-induced hepatic steatosis in mice. Additionally, Pac treatment reduced hepatocellular apoptosis. Non-targeted liver metabolomics analysis following Pac intervention revealed increased levels of acylcarnitine and oleic acid. Collectively, these findings suggest that Pac alleviates high-fat diet-induced hepatic lipid accumulation and damage by modulating gut microbiota, lipid metabolism, inflammation, and apoptosis. This comprehensive study provides valuable insights into the therapeutic potential of Pac and offers a reference for the development and utilization of Poria cocos resources in addressing NAFLD.

Association between sphingomyelin levels and gut microbiota abundance in Alzheimer's disease: a two-sample Mendelian randomization study

BACKGROUND

Several previous observational studies have shown that abnormal sphingomyelin metabolism may be implicated in the pathogenesis of Alzheimer's disease. To determine the causal relationship between sphingolipid abundance and gut microbiota abundance at the genetic level, we conducted a Mendelian randomization (MR) investigation.

METHODS

We first used the TwoSampleMR and MRPRESSO packages for conducting two-sample MR studies. Second, we utilized random effect inverse variance weighting (IVW) as the principal method of analysis and used MR‒Egger, the weighted median, the simple mode and the weighted mode as supplementary methods. Finally, we performed tests for heterogeneity and horizontal pleiotropy. These analyses were also conducted to evaluate the impact of individual SNPs on the outcomes of our analysis. A Bonferroni-corrected threshold of p = 2.4e-4(0.05/211) was considered significant, and p values less than 0·05 were considered to be suggestive of an association.

RESULTS

The results showed that sphingolipid levels were suggestively associated with the abundance of 6 gut microbiota taxa. Specifically, two taxa were positively correlated with sphingolipid levels, including the family Alcaligenaceae (p = 0.006, OR 95% CI = 1.109 [1.030-1.194]) and the species Ruminococcus callidus (p = 0.034, OR 95% CI = 1.217 [1.015-1.460]). In contrast, negative correlations were observed with the abundances of 4 gut microbiota taxa, including the genus Flavonifractor (p = 0.026, OR 95% CI = 0.804 [0.663-0.974]), the genus Streptococcus (p = 0.014, OR 95% CI = 0.909 [0.842-0.981]), the species Bacteroides caccae (p = 0.037, OR 95% CI = 0.870 [0.763-0.992]), and the species Haemophilus parainfluenzae (p = 0.006, beta 95% CI = -0.269 [-0.462, -0.076]). The results presented a normal distribution, with no anomalous values, heterogeneity, or horizontal pleiotropic effects detected.

CONCLUSIONS

This two-sample MR study revealed a potential causal relationship between sphingomyelin levels and gut microbiota abundance.

HEX-1 reduces colitis-driven colorectal cancer via inactivating the prolyl isomerase PIN1 sensitization and remodeling the gut microbiota

Metabolic reprogramming, a pivotal hallmark of cancer, plays a crucial role in both the initiation and progression of colorectal cancer (CRC). Despite the vast unknowns surrounding the identity and biological activities of most natural metabolites in diseases, our study, utilizing native metabolomics results through GC-MS/MS, identified a small molecule, 4,4-Dimethyl-2-cyclohexen-1-one, named HEX-1 in the serum of CRC patients. We have further explored and assessed its biological activities. HEX-1 suppressed the proliferation of cancer cells and tumorigenesis via the inactivation and sensitization of PIN1. Notably, HEX-1 exhibits similar functional effects as all-trans retinoic acid (atRA) but stands out by not inducing the degradation of PIN1 mRNA or protein expression, unlike biological compounds associated with atRA. HEX-1 demonstrated the ability to induce G1/S arrest in vitro and ameliorate the progression of inflammatory CRC in mice by remodeling the gut microbiota. As volatile organic compounds (VOCs), HEX-1 could be detected feasibly. Its unique ability to penetrate whole cell populations positions it as a promising approach for cancer therapy and as an enhancer for chemotherapy and immunotherapy. The findings suggest that HEX-1 holds the potential as a valuable addition to the armamentarium against CRC.

Regulatory role of gut microbiota in immunotherapy of hepatocellular carcinoma

BACKGROUND

The gut microbiota plays a role in triggering innate immunity and regulating the immune microenvironment (IME) of hepatocellular carcinoma (HCC) by acting on various signaling receptors and transcription factors through its metabolites and related molecules. Furthermore, there is an increasing recognition of the gut microbiota as a potential therapeutic target for HCC, given its ability to modulate the efficacy of immune checkpoint inhibitors (ICIs).

OBJECTIVE

This review will discuss the mechanisms of gut microbiota in modulating immunotherapy of HCC, the predictive value of efficacy, and the therapeutic strategies for modulating the gut microbiota in detail.

METHODS

We conducted a systematic literature search in PubMed, Embase, Scopus, Cochrane Library, China National Knowledge Infrastructure, and Wanfang Chinese databases for articles involving the influence of gut microbiota on HCC immunotherapy.

RESULTS

The mechanisms underlying the effect of gut microbiota on HCC immunotherapy include gut-liver axis, tumor immune microenvironment (TIME), and antibodies. Patients who benefit from ICIs exhibit a higher abundance of gut microbiota. Antibiotics, fecal microbiota transplantation (FMT), probiotics, and prebiotics are effective methods to regulate gut microbiota.

CONCLUSION

The strong connection between the liver and gut will provide numerous opportunities for the development of microbiome-based diagnostics, treatments, or prevention strategies for HCC patients.

Gut microbiota-mediated gut-liver axis: a breakthrough point for understanding and treating liver cancer

The trillions of commensal microorganisms living in the gut lumen profoundly influence the physiology and pathophysiology of the liver through a unique gut-liver axis. Disruptions in the gut microbial communities, arising from environmental and genetic factors, can lead to altered microbial metabolism, impaired intestinal barrier and translocation of microbial components to the liver. These alterations collaboratively contribute to the pathogenesis of liver disease, and their continuous impact throughout the disease course plays a critical role in hepatocarcinogenesis. Persistent inflammatory responses, metabolic rearrangements and suppressed immunosurveillance induced by microbial products underlie the pro-carcinogenic mechanisms of gut microbiota. Meanwhile, intrahepatic microbiota derived from the gut also emerges as a novel player in the development and progression of liver cancer. In this review, we first discuss the causes of gut dysbiosis in liver disease, and then specify the pivotal role of gut microbiota in the malignant progression from chronic liver diseases to hepatobiliary cancers. We also delve into the cellular and molecular interactions between microbes and liver cancer microenvironment, aiming to decipher the underlying mechanism for the malignant transition processes. At last, we summarize the current progress in the clinical implications of gut microbiota for liver cancer, shedding light on microbiota-based strategies for liver cancer prevention, diagnosis and therapy.

The Role of the Gut-Biliary-Liver Axis in Primary Hepatobiliary Liver Cancers: From Molecular Insights to Clinical Applications

Background: Hepatobiliary liver cancers (HBLCs) represent the sixth most common neoplasm in the world. Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) constitute the main HBLC types, with alarming epidemiological projections. Methods: In recent decades, alterations in gut microbiota, with mutual implications on the gut-liver axis and gut-biliary axis permeability status, have been massively investigated and proposed as HBLC pathogenetic deus ex machina. Results: In the HCC setting, elevated intestinal levels of Escherichia coli and other Gram-negative bacteria have been demonstrated, resulting in a close association with increased lipopolysaccharide (LPS) serum levels and, consequently, chronic systemic inflammation. In contrast, the intestinal microbiota of HCC individuals feature reduced levels of Lactobacillus spp., Bifidobacterium spp., and Enterococcus spp. In the CC setting, evidence has revealed an increased expression of Lactobacillus spp., with enhanced levels of Actynomices spp. and Alloscardovia spp. Besides impaired strains/species representation, gut-derived metabolites, including bile acids (BAs), short-chain fatty acids (SCFAs), and oxidative-stress-derived products, configure a network severely impacting the progression of HBLC. Conclusions: In the era of Precision Medicine, the clarification of microbiota composition and functioning in HCC and CC settings can contribute to the identification of individual signatures, potentially providing novel diagnostic markers, therapeutic approaches, and prognostic/predictive tools.

Gut microbiota dysbiosis in infantile cholestatic hepatopathy

Background

Cholestatic hepatopathy is common in infants. While many studies link gut microbiota to liver and gallbladder diseases, the relationship between infantile cholestatic hepatopathy (ICH) and gut microbiota remains unclear.

Methods

We collected stool samples from 19 healthy controls and 33 infants with ICH aged ≤3 months, then determined the intestinal microbiota by 16S rDNA sequencing. The differences of microbiota structure and functional between the two groups were analyzed.

Results

Alpha-diversity analysis showed that the Chao1 and ACE indexes were significantly higher in the ICH group than control group (p < 0.05). LEfSe analysis showed that 18 bacteria taxa, including Streptococcus, Streptococcaceae, and Staphylococcales, enriched significantly in the ICH group, and 3 bacteria taxa were enriched in the control group. At the genus level, the relative abundance of Streptococcus, Escherichia-Shigella, and Lactobacillus in ICH group was higher than control group (p < 0.05). The Receiver Operating Characteristic (ROC) analysis demonstrated that Streptococcus was highly valuable in distinguishing ICH from healthy controls. Moreover, functional prediction analysis identified 59 metabolic pathways potentially associated with ICH.

Conclusion

Gut microbiota dysbiosis is associated with infantile cholestatic hepatopathy, and Streptococcus can be used as an essential biomarker to identify ICH.

Silymarin mediates the gut-liver axis pathway to alleviate Carassius auratus hepatic lipid metabolism disorders caused by carbonate exposure

An 8-week feeding trial was conducted to investigate the mechanism of silymarin alleviating the abnormal lipid metabolism of Hefang Crucian Carp (HCC) (13.43 ± 0.059 g) liver caused by carbonate exposure. The fish were randomly divided into three groups: Control group (group B, 0 g/L carbonate, 0 mg/kg silymarin), carbonate stress group (group CA, 3 g/L carbonate, 0 mg/kg silymarin) and silymarin group (group SI, 3 g/L carbonate, 60 mg/kg silymarin). The results showed that the growth performance of group CA was significantly increased compared with group B. Compared with CA group, brush villi in SI group recovered significantly, and the width of submucosa decreased. Compared with group B, the intestinal barrier was damaged and permeability increased in group CA, while the damage was alleviated in group SI. Intestinal microbiota analysis showed that the bacterial community function genes related to lipopolysaccharide biosynthesis protein and lipopolysaccharide biosynthesis in CA group were higher than those in B and SI groups, and it was found that the change of LPS content in fish was echoed by the results of intestinal microflora. Compared with group B, the liver of group CA was damaged and the lipid metabolism process was abnormal, resulting in lipid metabolism disorder. SI group alleviated the liver damage caused by carbonate exposure, promoted the process of liver lipid synthesis, and balanced the body's lipid metabolism. More than 50 % of the metabolites are closely related to lipids and lipid molecules. The most metabolites in metabolism are oxidative phosphorylation and pyruvate metabolism. In summary, this study demonstrated that silymarin alleviating carbonate exposure altered intestinal microbiota homeostasis in HCC, leading to intestinal inflammation and increased mucosal barrier permeability, inhibiting LPS synthesis and absorption, preventing it from entering the liver through the intestinal liver, and increasing oxidative stress in the liver and abnormal lipid metabolism in the liver, thereby leading to liver injury. To provide theoretical basis for the development and utilization of silymarin functional feed additives and the mitigation strategy of carbonate exposure to liver damage in fish.

Emerging insights into the gut microbiota as a key regulator of immunity and response to immunotherapy in hepatocellular carcinoma

The gut microbiota, a complex microbial ecosystem closely connected to the liver via the portal vein, has emerged as a critical regulator of liver health and disease. Numerous studies have underscored its role in the onset and progression of liver disorders, including alcoholic liver disease, metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction-associated steatohepatitis (MASH), liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). This review provides a comprehensive overview of current insights into the influence of the gut microbiota on HCC progression, particularly its effects on immune cells within the HCC tumor microenvironment (TME). Furthermore, we explore the potential of gut microbiota-targeted interventions, such as antibiotics, probiotics, prebiotics, and fecal microbiota transplantation (FMT), to modulate the immune response and improve outcomes of immunotherapy in HCC. By synthesizing insights from recent studies, this review aims to highlight microbiota-based strategies that may enhance immunotherapy outcomes, advancing personalized approaches in HCC treatment.

Dysbiosis and extraintestinal cancers

The gut microbiota plays a crucial role in safeguarding host health and driving the progression of intestinal diseases. Despite recent advances in the remarkable correlation between dysbiosis and extraintestinal cancers, the underlying mechanisms are yet to be fully elucidated. Pathogenic microbiota, along with their metabolites, can undermine the integrity of the gut barrier through inflammatory or metabolic pathways, leading to increased permeability and the translocation of pathogens. The dissemination of pathogens through the circulation may contribute to the establishment of an immune-suppressive environment that promotes carcinogenesis in extraintestinal organs either directly or indirectly. The oncogenic cascade always engages in the disruption of hormonal regulation and inflammatory responses, the induction of genomic instability and mutations, and the dysregulation of adult stem cell proliferation. This review aims to comprehensively summarize the existing evidence that points to the potential role of dysbiosis in the malignant transformation of extraintestinal organs such as the liver, breast, lung, and pancreas. Additionally, we delve into the limitations inherent in current methodologies, particularly the challenges associated with differentiating low loads gut-derived microbiome within tumors from potential sample contamination or symbiotic microorganisms. Although still controversial, an understanding of the contribution of translocated intestinal microbiota and their metabolites to the pathological continuum from chronic inflammation to tumors could offer a novel foundation for the development of targeted therapeutics.

Inflammation and Immunity in Liver Neoplasms: Implications for Future Therapeutic Strategies

Over the past two decades, the "hallmarks of cancer" have revolutionized cancer research and highlighted the crucial roles of inflammation and immunity. Protumorigenic inflammation promotes cancer development along with inhibition of antitumor immunity, shaping the tumor microenvironment (TME) toward a tumor-permissive state and further enhancing the malignant potential of cancer cells. This immunosuppressive TME allows tumors to evade immunosurveillance. Thus, understanding the complex interplay between tumors and the immune system within the TME has become pivotal, especially with the advent of immunotherapy. Although immunotherapy has achieved notable success in many malignancies, primary liver cancer, particularly hepatocellular carcinoma, presents unique challenges. The hepatic immunosuppressive environment poses obstacles to the effectiveness of immunotherapy, along with high mortality rates and limited treatment options for patients with liver cancer. In this review, we discuss current understanding of the complex immune-mediated mechanisms underlying liver neoplasms, focusing on hepatocellular carcinoma and liver metastases. We describe the molecular and cellular heterogeneity within the TME, highlighting how this presents unique challenges and opportunities for immunotherapy in liver cancers. By unraveling the immune landscape of liver neoplasms, this review aims to contribute to the development of more effective therapeutic interventions, ultimately improving clinical outcomes for patients with liver cancer.

Gut-X axis

Recent advances in understanding the modulatory functions of gut and gut microbiota on human diseases facilitated our focused attention on the contribution of the gut to the pathophysiological alterations of many extraintestinal organs, including the liver, heart, brain, lungs, kidneys, bone, skin, reproductive, and endocrine systems. In this review, we applied the "gut-X axis" concept to describe the linkages between the gut and other organs and discussed the latest findings related to the "gut-X axis," including the underlying modulatory mechanisms and potential clinical intervention strategies.

Microbiome interplays in the gut-liver axis: implications for liver cancer pathogenesis and therapeutic insights

Globally, primary liver cancer (PLC) ranks the most fatal malignancy. Most of the patients are in advanced stage of PLC at the very time they are diagnosed with it, accounting much for its poor prognosis. With the advancement of modern medical research and care system, the main etiology of PLC more and more switches from hepatitis viruses such as HAV, HBV, HCV, HEV to other causes like metabolism-associated steatohepatitis (MASH) and metabolic-associated fatty liver disease (MAFLD). As a result, it is of great necessity to find out new ways for treatment and early diagnosis to cope with this problem. Nowadays, as the mechanism of the Gut-Liver Axis in the formation of MAFLD, MASH and PLC has been gradually elucidated. The association between gut microbiome and the formation of PLC is of great significance to take an insight into. In this review, we present the concept of Gut-Liver Axis and its function in the mutual influence between gut microbiota and PLC from several aspects in which we will focus on the structure of gut barrier and the functional influences the gut microbiota have on the immune response and metabolic changes on human liver. Furthermore, we conclude the potential association of gut microbiota constitution with the PLC. Eventually, we hope this review can offer novel instructions for early diagnosis and treatment for liver cancer.

Exploring the association between pro-inflammatory diets and chronic liver diseases: evidence from the UK Biobank

Background

Chronic liver diseases (CLD) continue to pose a significant global burden, potentially exacerbated by pro-inflammatory diets. This study explores the relationship between the Dietary Inflammatory Index (DII), a measure of dietary inflammatory potential, and CLD risk.

Methods

Utilizing data from the UK Biobank cohort, we assessed the dietary information and calculated the DII for each participant. Cox proportional hazards models and Fine-Gray competing risk models were employed to evaluate the association between DII and CLD incidence, adjusting for potential confounders.

Results

Our analysis included 121,329 participants with a median follow-up of 604.43 weeks, during which 4,018 developed CLD. A higher DII, indicating a more inflammatory diet, was associated with a 16% increased risk of CLD [hazard ratio (HR) = 1.162, P = 0.001], with each unit increase in DII elevating the risk by 3.3% (HR: 1.033, P < 0.001). A significant linear association between DII and CLD was observed. Competing risk analyses, which accounted for cirrhosis, liver cancer, and death, supported these findings. Subgroup analyses confirmed the robustness of the DII's association across various demographic and lifestyle factors. Moreover, a higher DII was positively associated with the progression of CLD to cirrhosis. Sensitivity analyses, including energy-adjusted DII and typical dietary DII, reinforced our results. Additionally, adherence to anti-inflammatory dietary patterns, as indicated by higher Healthy Eating Index 2020 and Mediterranean Diet Score values, was inversely associated with CLD risk.

Conclusion

Our study highlights the potential benefits of adopting anti-inflammatory diets as a strategy for the prevention and management of CLD. Comprehensive dietary interventions may play a pivotal role in mitigating the global burden of CLD.

Human papillomavirus, vaginal microbiota and metagenomics: the interplay between development and progression of cervical cancer

Persistent infection with oncogenic human papillomavirus (HPV) types, such as HPV 16 or 18, is a major factor in cervical cancer development. However, only a small percentage of infected women develop cancer, indicating that other factors are involved. Emerging evidence links vaginal microbiota with HPV persistence and cancer progression. Alterations in microbial composition, function, and metabolic pathways may contribute to this process. Despite the potential of metagenomics to explore these interactions, studies on the vaginal microbiota's role in cervical cancer are limited. This review systematically examines the relationship between cervical microbiota, HPV, and cervical cancer by analyzing studies from PubMed, EBSCO, and Scopus. We highlight how microbial diversity influences HPV persistence and cancer progression, noting that healthy women typically have lower microbiota diversity and higher Lactobacillus abundance compared to HPV-infected women, who exhibit increased Gardenella, Prevotella, Sneathia, Megasphaera, Streptococcus, and Fusobacterium spp., associated with dysbiosis. We discuss how microbial diversity is associated with HPV persistence and cancer progression, noting that studies suggest healthy women typically have lower microbiota diversity and higher Lactobacillus abundance, while HPV-infected women exhibit increased Gardnerella, Prevotella, Sneathia, Megasphaera, Streptococcus, and Fusobacterium spp., indicative of dysbiosis. Potential markers such as Gardnerella and Prevotella have been identified as potential microbiome biomarkers associated with HPV infection and cervical cancer progression. The review also discusses microbiome-related gene expression changes in cervical cancer patients. However, further research is needed to validate these findings and explore additional microbiome alterations in cancer progression.

Intestinal Akkermansia muciniphila complements the efficacy of PD1 therapy in MAFLD-related hepatocellular carcinoma

Immune checkpoint inhibitors are not effective for metabolic dysfunction-associated fatty liver disease (MAFLD)-hepatocellular carcinoma (HCC) patients, and identifying the key gut microbiota that contributes to immune resistance in these patients is crucial. Analysis using 16S rRNA sequencing reveals a decrease in Akkermansia muciniphila (Akk) during MAFLD-promoted HCC development. Administration of Akk ameliorates liver steatosis and effectively attenuates the tumor growth in orthotopic MAFLD-HCC mouse models. Akk repairs the intestinal lining, with a decrease in the serum lipopolysaccharide (LPS) and bile acid metabolites, along with decrease in the populations of monocytic myeloid-derived suppressor cells (m-MDSCs) and M2 macrophages. Akk in combination with PD1 treatment exerts maximal growth-suppressive effect in multiple MAFLD-HCC mouse models with increased infiltration and activation of T cells. Clinically, low Akk levels are correlated with PD1 resistance and poor progression-free survival. In conclusion, Akk is involved in the immune resistance of MAFLD-HCC and serves as a predictive biomarker for PD1 response in HCC.

NLRP6 overexpression improves nonalcoholic fatty liver disease by promoting lipid oxidation and decomposition in hepatocytes through the AMPK/CPT1A/PGC1A pathway

OBJECTIVES

To investigate the regulatory role of nucleotide-bound oligomerized domain-like receptor containing pyrin-domain protein 6 (NLRP6) in liver lipid metabolism and non-alcoholic fatty liver disease (NAFLD).

METHODS

Mouse models with high-fat diet (HFD) feeding for 16 weeks (n=6) or with methionine choline-deficient diet (MCD) feeding for 8 weeks (n=6) were examined for the development of NAFLD using HE and oil red O staining, and hepatic expressions of NLRP6 were detected with RT-qPCR, Western blotting, and immunohistochemical staining. Cultured human hepatocytes (LO2 cells) with adenovirus-mediated NLRP6 overexpression or knock-down were treated with palmitic acid (PA) in the presence or absence of compound C (an AMPK inhibitor), and the changes in cellular lipid metabolism were examined by measuring triglyceride, ATP and β-hydroxybutyrate levels and using oil red staining, RT-qPCR, and Western blotting.

RESULTS

HFD and MCD feeding both resulted in the development of NAFLD in mice, which showed significantly decreased NLRP6 expression in the liver. In PA-treated LO2 cells, NLRP6 overexpression significantly decreased cellular TG content and lipid deposition, while NLRP6 knockdown caused the opposite effects. NLRP6 overexpression in PA-treated LO2 cells also increased mRNA and protein expressions of PGC1A and CPT1A, levels of ATP and β-hydroxybutyrate, and the phosphorylation level of AMPK pathway; the oxidative decomposition of lipids induced by Ad-NLRP6 was inhibited by the use of AMPK inhibitors.

CONCLUSIONS

NLRP6 overexpression promotes lipid oxidation and decomposition through AMPK/CPT1A/PGC1A to alleviate lipid deposition in hepatocytes.

Prevention of liver cancer in the era of next-generation antivirals and obesity epidemic

Preventive interventions are expected to substantially improve the prognosis of patients with primary liver cancer, predominantly HCC and cholangiocarcinoma. HCC prevention is challenging in the face of the evolving etiological landscape, particularly the sharp increase in obesity-associated metabolic disorders, including metabolic dysfunction-associated steatotic liver disease. Next-generation anti-HCV and HBV drugs have substantially reduced, but not eliminated, the risk of HCC and have given way to new challenges in identifying at-risk patients. The recent development of new therapeutic agents and modalities has opened unprecedented opportunities to refine primary, secondary, and tertiary HCC prevention strategies. For primary prevention (before exposure to risk factors), public health policies, such as universal HBV vaccination, have had a substantial prognostic impact. Secondary prevention (after or during active exposure to risk factors) includes regular HCC screening and chemoprevention. Emerging biomarkers and imaging modalities for HCC risk stratification and detection may enable individual risk-based personalized and cost-effective HCC screening. Clinical studies have suggested the potential utility of lipid-lowering, antidiabetic/obesity, and anti-inflammatory agents for secondary prevention, and some of them are being evaluated in prospective clinical trials. Computational and experimental studies have identified potential chemopreventive strategies directed at diverse molecular, cellular, and systemic targets for etiology-specific and/or agnostic interventions. Tertiary prevention (in conjunction with curative-intent therapies for HCC) is an area of active research with the development of new immune-based neoadjuvant/adjuvant therapies. Cholangiocarcinoma prevention may advance with recent efforts to elucidate risk factors. These advances will collectively lead to substantial improvements in liver cancer mortality rates.

Gut Microbiome Modulation in Hepatocellular Carcinoma: Preventive Role in NAFLD/NASH Progression and Potential Applications in Immunotherapy-Based Strategies

Hepatocellular carcinoma (HCC) is a heterogeneous tumor associated with several risk factors, with non-alcoholic fatty liver disease (NAFLD) emerging as an important cause of liver tumorigenesis. Due to the obesity epidemics, the occurrence of NAFLD has significantly increased with nearly 30% prevalence worldwide. HCC often arises in the background of chronic liver disease (CLD), such as nonalcoholic steatohepatitis (NASH) and cirrhosis. Gut microbiome (GM) alterations have been linked to NAFLD progression and HCC development, with several investigations reporting a crucial role for the gut-liver axis and microbial metabolites in promoting CLD. Moreover, the GM affects liver homeostasis, energy status, and the immune microenvironment, influencing the response to immunotherapy with interesting therapeutic implications. In this review, we summarize the main changes in the GM and derived metabolites (e.g., short-chain fatty acids and bile acids) occurring in HCC patients and influencing NAFLD progression, emphasizing their potential as early diagnostic biomarkers and prognostic tools. We discuss the weight loss effects of diet-based interventions and healthy lifestyles for the treatment of NAFLD patients, highlighting their impact on the restoration of the intestinal barrier and GM structure. We also describe encouraging preclinical findings on the modulation of GM to improve liver functions in CLD, boost the antitumor immune response (e.g., probiotic supplementations or anti-hypercholesterolemic drug treatment), and ultimately delay NAFLD progression to HCC. The development of safe and effective strategies that target the gut-liver axis holds promise for liver cancer prevention and treatment, especially if personalized options will be considered.

Gut‑liver axis in liver disease: From basic science to clinical treatment (Review)

Incidence of a number of liver diseases has increased. Gut microbiota serves a role in the pathogenesis of hepatitis, cirrhosis and liver cancer. Gut microbiota is considered 'a new virtual metabolic organ'. The interaction between the gut microbiota and liver is termed the gut‑liver axis. The gut‑liver axis provides a novel research direction for mechanism of liver disease development. The present review discusses the role of the gut‑liver axis and how this can be targeted by novel treatments for common liver diseases.

Purslane (Portulaca oleracea L.) polysaccharide attenuates carbon tetrachloride-induced acute liver injury by modulating the gut microbiota in mice

This study investigated the preventive and protective effects of Portulaca oleracea polysaccharides (PP) on Acute liver injury (ALI) in mice and its regulatory effects on intestinal microorganisms, and explored the underlying protective mechanisms. Initially, PP was administered, and then CCl4 was used to induce the mouse ALI model. Serum and liver markers were measured by ELISA. The fecal microbiota was analyzed by 16S rRNA sequencing. The results showed that PP significantly decreased the expression levels of ALT and AST in the serum of mice. The expression levels of MDA, TNF-α, and IL-6 in liver tissue were found to be reduced, while the levels of GSH and SOD increased. At the same time, PP increased the number of Bacteroides, reduced the number of Proteobacteria, activated the GAG degradation pathway, protected the integrity of the intestinal barrier, inhibited oxidative stress and reduced inflammation, thereby assisting the prevention and protection of ALI.

Emodin induced hepatic steatosis in BALb/c mice by modulating the gut microbiota composition and fatty acid metabolism

Introduction

The aim of this study is to examine the physiological effects of emodin on intestinal microorganisms and the liver in the BALb/c mice.

Method and Results

Following an 8-week administration of emodin at doses of 25, 50, and 100 mg/kg/day,pathological analyses revealed that emodin significantly reduced the colon length, induced colonic crypt inflammation,diminished the colonic mucus layer,and decreased the fluorescence intensity of colonic tight junction proteins ZO-1 and Occludin. Concurrently, 16S rDNA gene sequencing corroborated that emodin altered the diversity and composition of the intestinal microbiota by increasing the Firmicutes to Bacteroides ratio. Simultaneously, the non-targeted metabolomics analyses exhibited significant alternations in both short chain fatty acids and free fatty acids between the emodin-treated and the normal groups, indicating emodin-induced disturbance in intestinal metabolic disorder. Furthermore, emodin exhibited a significant elevation in LPS levels in colon, serum and liver as well an marked increase in the levels of TC, TG, AST, and ALT in serum. Additionally, histological examination employing by HE and oil-red O staining furtherly verified that the administration of varying doses emodin induced hepatic inflammation and lipid accumulation. Whereas qRT-PCR and Western blot analyses demonstrated that the administering of varying doses of emodin upregulated the mRNA levels of TNF-α, IL-1β, IL-6, and IL-18 as well as the expression of TLR4, Myd88, and P-65. Following the combined administration of probiotics, the high-dose emodin did not significantly influence ALT and AST levels in mice. However, the faeces of the high-dose emodin transplanted in mice and induced a significant increase in AST levels and in the relative abundance of Firmicutes and Proteobacteria.

Discussion

These findings further corroborate that emodin induces liver injury via the intestinal dysfunction. These findings suggested that emodin may disrupt intestinal microbiota and resulted in significant alternations in endogenous metabolites in mice, thereby facilitating the entry of LPS and FFAs into the liver, potentially leading to hepatic injury.

Alcohol-associated liver cancer

Heavy alcohol intake induces a wide spectrum of liver diseases ranging from steatosis, steatohepatitis, cirrhosis, and HCC. Although alcohol consumption is a well-known risk factor for the development, morbidity, and mortality of HCC globally, alcohol-associated hepatocellular carcinoma (A-HCC) is poorly characterized compared to viral hepatitis-associated HCC. Most A-HCCs develop after alcohol-associated cirrhosis (AC), but the direct carcinogenesis from ethanol and its metabolites to A-HCC remains obscure. The differences between A-HCC and HCCs caused by other etiologies have not been well investigated in terms of clinical prognosis, genetic or epigenetic landscape, molecular mechanisms, and heterogeneity. Moreover, there is a huge gap between basic research and clinical practice due to the lack of preclinical models of A-HCC. In the current review, we discuss the pathogenesis, heterogeneity, preclinical approaches, epigenetic, and genetic profiles of A-HCC, and discuss the current insights into and the prospects for future research on A-HCC. The potential effect of alcohol on cholangiocarcinoma and liver metastasis is also discussed.

Modulation of gut microbiota by probiotics to improve the efficacy of immunotherapy in hepatocellular carcinoma

Hepatocellular carcinoma, a common malignancy of the digestive system, typically progresses through a sequence of hepatitis, liver fibrosis, cirrhosis and ultimately, tumor. The interaction between gut microbiota, the portal venous system and the biliary tract, referred to as the gut-liver axis, is crucial in understanding the mechanisms that contribute to the progression of hepatocellular carcinoma. Mechanisms implicated include gut dysbiosis, alterations in microbial metabolites and increased intestinal barrier permeability. Imbalances in gut microbiota, or dysbiosis, contributes to hepatocellular carcinoma by producing carcinogenic substances, disrupting the balance of the immune system, altering metabolic processes, and increasing intestinal barrier permeability. Concurrently, accumulating evidence suggests that gut microbiota has the ability to modulate antitumor immune responses and affect the efficacy of cancer immunotherapies. As a new and effective strategy, immunotherapy offers significant potential for managing advanced stages of hepatocellular carcinoma, with immune checkpoint inhibitors achieving significant advancements in improving patients' survival. Probiotics play a vital role in promoting health and preventing diseases by modulating metabolic processes, inflammation and immune responses. Research indicates that they are instrumental in boosting antitumor immune responses through the modulation of gut microbiota. This review is to explore the relationship between gut microbiota and the emergence of hepatocellular carcinoma, assess the contributions of probiotics to immunotherapy and outline the latest research findings, providing a safer and more cost-effective potential strategy for the prevention and management of hepatocellular carcinoma.

Constructing and validating pan-apoptosis-related features for predicting prognosis and immunotherapy response in hepatocellular carcinoma

The study aimed to develop a prognostic model for Hepatocellular Carcinoma (HCC) based on pan-apoptosis-related genes, a novel inflammatory programmed cell death form intricately linked to HCC progression. Utilizing transcriptome sequencing and clinical data from the TCGA database, we identified six crucial pan-apoptosis-related genes through statistical analyses. These genes were then employed to construct a prognostic model that accurately predicts overall survival rates in HCC patients. Our findings revealed a strong correlation between the model's risk scores and tumor microenvironment (TME) status, immune cell infiltration, and immune checkpoint expression. Furthermore, we screened for drugs with potential therapeutic efficacy in high- and low-risk HCC groups. Notably, PPP2R5B gene knockdown was found to inhibit HCC cell proliferation and clonogenic capacity, suggesting its role in HCC progression. In conclusion, this study presents a novel pan-apoptosis gene-based prognostic risk model for HCC, providing valuable insights into patient TME status and guiding the selection of targeted therapies and immunotherapies.

Early-life antibiotic exposure aggravate the metabolic dysfunction-associated steatotic liver disease associated hepatocellular carcinoma

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) asscociated hepatocellular carcinoma (HCC) is becoming a growing concern in global healthcare. The early-life gut microbiota plays a crucial role in maintaining healthy. However, the impact of early-life gut microbiota dysbiosis on the advancement of MASLD-HCC remains inadequately understood.

METHODS

In the present study, we investigated the role of early-life gut microbiota in the development of MASLD-HCC in streptozotocin and high-fat diet (STZ-HFD) induced mouse model. We recorded the body weight and lifespan, and dynamically monitored the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (T-CHO) and blood glucose in the serum monthly. In addition, we examined various immune cells present in the liver, such as T cells, B cells, NK cells, NKT cells, αβT cells, γδT cells, macrophage and MDSC cells by flow cytometry and conducted liquid chromatography mass spectrometry (LC-MS) based analysis on liver tissue from control and early-life antibiotic exposure mice (early-Abx) MASLD-HCC mice.

RESULTS

We found that early-Abx mice suffered from more severe tumor burden and further confirmed that hepatocytes and immune cells were all disturbed. Importantly, early-life antibiotic exposure alters the liver metabolic profiling especially glycerophospholipids and lipid accumulation. Furthermore, mice exposed to antibiotics in early-life showed disturbances in glucose metabolism and developed insulin resistance.

CONCLUSIONS

Collectively, our findings revealed that early-life antibiotic exposure accelerated the progression of MASLD-HCC by impairing the hepatocytes, immune homeostasis and metabolites persistently, highlighting the importance of the early-life microbiota in the development of MASLD-HCC.

Trojan-Horse Strategy Targeting the Gut-Liver Axis Modulates Gut Microbiome and Reshapes Microenvironment for Orthotopic Hepatocellular Carcinoma Therapy

Reversing the hepatic inflammatory and immunosuppressive microenvironment caused by gut microbiota-derived lipopolysaccharides (LPS), accumulating to the liver through the gut-liver axis, is crucial for suppressing hepatocellular carcinoma (HCC) and metastasis. However, synergistically manipulating LPS-induced inflammation and gut microbiota remains a daunting task. Herein, a Trojan-horse strategy is proposed using an oral dextran-carbenoxolone (DEX-CBX) conjugate, which combines prebiotic and glycyrrhetinic acid (GA) homologs, to targeted delivery GA to HCC through the gut-liver axis for simultaneous modulation of hepatic inflammation and gut microbiota. In the orthotopic HCC model, a 95-45% reduction in the relative abundances of LPS-associated microbiota is observed, especially Helicobacter, caused by DEX-CBX treatment over phosphate-buffered saline (PBS) treatment. Notably, a dramatic increase (37-fold over PBS) in the abundance of Akkermansia, which is known to strengthen systemic immune response, is detected. Furthermore, DEX-CBX significantly increased natural killer T cells (5.7-fold) and CD8+ T cells (3.9-fold) as well as decreased M2 macrophages (59% reduction) over PBS treatment, resulting in a tumor suppression rate of 85.4%. DEX-CBX is anticipated to offer a novel strategy to precisely modulate hepatic inflammation and the gut microbiota to address both the symptoms and root causes of LPS-induced immunosuppression in HCC.

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.

The impact of traditional Chinese medicine and dietary compounds on modulating gut microbiota in hepatic fibrosis: A review

Traditional Chinese medicine (TCM) and dietary compounds have a profound influence on the regulation of gut microbiota (GM) in hepatic fibrosis (HF). Certain substances found in both food and herbs that are edible and medicinal, such as dietary fiber, polyphenols, and polysaccharides, can generate beneficial metabolites like short-chain fatty acids (SCFAs), bile acids (BAs), and tryptophan (Trp). These compounds contribute to regulate the GM, reduce levels of endotoxins in the liver, and alleviate fibrosis and inflammation in the liver. Furthermore, they enhance the composition and functionality of GM, promoting the growth of beneficial bacteria while inhibiting the proliferation of harmful bacteria. These mechanisms mitigate the inflammatory response in the intestines and maintain the integrity of the intestinal barrier. The purpose of this review is to analyze how the GM regulates the pathogenesis of HF, evaluate the regulatory effect of TCM and dietary compounds on the intestinal microflora, with a particular emphasis on modulating flora structure, enhancing gut barrier function, and addressing associated pathogenic factors, thereby provide new insights for the treatment of HF.

Novel Biomarkers for Early Detection of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality globally. Most patients present with late diagnosis, leading to poor prognosis. This narrative review explores novel biomarkers for early HCC detection. We conducted a comprehensive literature review analyzing protein, circulating nucleic acid, metabolite, and quantitative proteomics-based biomarkers, evaluating the advantages and limitations of each approach. While established markers like alpha-fetoprotein (AFP), des-gamma-carboxy prothrombin, and AFP-L3 remain relevant, promising candidates include circulating tumor DNA, microRNAs, long noncoding RNAs, extracellular vesicle, and metabolomic biomarkers. Multi-biomarker panels like the GALAD score, Oncoguard, and Helio liver test show promise for improved diagnostic accuracy. Non-invasive approaches like urine and gut microbiome analysis are also emerging possibilities. Integrating these novel biomarkers with current screening protocols holds significant potential for earlier HCC detection and improved patient outcomes. Future research should explore multi-biomarker panels, omics technologies, and artificial intelligence to further enhance early HCC diagnosis and management.

Impact of gut microbiota on metabolic dysfunction-associated steatohepatitis and hepatocellular carcinoma: pathways, diagnostic opportunities and therapeutic advances

Metabolic dysfunction-associated steatohepatitis (MASH) and progression to hepatocellular carcinoma (HCC) exhibits distinct molecular and immune characteristics. These traits are influenced by multiple factors, including the gut microbiome, which interacts with the liver through the "gut-liver axis". This bidirectional relationship between the gut and its microbiota and the liver plays a key role in driving various liver diseases, with microbial metabolites and immune responses being central to these processes. Our review consolidates the latest research on how gut microbiota contributes to MASH development and its progression to HCC, emphasizing new diagnostic and therapeutic possibilities. We performed a comprehensive literature review across PubMed/MedLine, Scopus, and Web of Science from January 2000 to August 2024, focusing on both preclinical and clinical studies that investigate the gut microbiota's roles in MASH and HCC. This includes research on pathogenesis, as well as diagnostic and therapeutic advancements related to the gut microbiota. This evidence emphasizes the critical role of the gut microbiome in the pathogenesis of MASH and HCC, highlighting the need for further clinical studies and trials. This is to refine diagnostic techniques and develop targeted therapies that exploit the microbiome's capabilities, aiming to enhance patient care in liver diseases.

Role of microbiome in autoimmune liver diseases

The microbiome plays a crucial role in integrating environmental influences into host physiology, potentially linking it to autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. All autoimmune liver diseases are associated with reduced diversity of the gut microbiome and altered abundance of certain bacteria. However, the relationship between the microbiome and liver diseases is bidirectional and varies over the course of the disease. This makes it challenging to dissect whether such changes in the microbiome are initiating or driving factors in autoimmune liver diseases, secondary consequences of disease and/or pharmacological intervention, or alterations that modify the clinical course that patients experience. Potential mechanisms include the presence of pathobionts, disease-modifying microbial metabolites, and more nonspecific reduced gut barrier function, and it is highly likely that the effect of these change during the progression of the disease. Recurrent disease after liver transplantation is a major clinical challenge and a common denominator in these conditions, which could also represent a window to disease mechanisms of the gut-liver axis. Herein, we propose future research priorities, which should involve clinical trials, extensive molecular phenotyping at high resolution, and experimental studies in model systems. Overall, autoimmune liver diseases are characterized by an altered microbiome, and interventions targeting these changes hold promise for improving clinical care based on the emerging field of microbiota medicine.

Failure of colonization following gut microbiota transfer exacerbates DSS-induced colitis

To study the impact of differing specific pathogen-free gut microbiomes (GMs) on a murine model of inflammatory bowel disease, selected GMs were transferred using embryo transfer (ET), cross-fostering (CF), and co-housing (CH). Prior work showed that the GM transfer method and the microbial composition of donor and recipient GMs can influence microbial colonization and disease phenotypes in dextran sodium sulfate-induced colitis. When a low richness GM was transferred to a recipient with a high richness GM via CH, the donor GM failed to successfully colonize, and a more severe disease phenotype resulted when compared to ET or CF, where colonization was successful. By comparing CH and gastric gavage for fecal material transfer, we isolated the microbial component of this effect and determined that differences in disease severity and survival were associated with microbial factors rather than the transfer method itself. Mice receiving a low richness GM via CH and gastric gavage exhibited greater disease severity and higher expression of pro-inflammatory immune mediators compared to those receiving a high richness GM. This study provides valuable insights into the role of GM composition and colonization in disease modulation.

The biofunction of Akkermansia muciniphila in intestinal-related diseases

Intestinal homeostasis is essential for maintaining human health, and its dysfunction is related to the onset and progression of various diseases, including immune and metabolic disorders, and even tumorigenesis. Intestinal microbiota plays a critical role in intestinal homeostasis, with Akkermansia muciniphila (A. muciniphila) emerging as a key commensal bacterium utilizing mucin as its sole carbon and nitrogen source. A. muciniphila has been recognized in both experimental and clinical studies for its beneficial role in managing intestinal inflammation, tumors, functional gastrointestinal disorders, and secondary conditions such as liver and metabolic diseases. This review provides a comprehensive overview of the research history and current understanding of A. muciniphila, its association with various intestinal-related diseases, and the potential mechanisms behind its effects. This paper also explores the possibilities of leveraging the probiotic enzyme such as the active ingredients of A. muciniphila for the innovative clinical treatment of intestinal-related diseases.

Gut Microbiota-Derived Butyrate Induces Epigenetic and Metabolic Reprogramming in Myeloid-Derived Suppressor Cells to Alleviate Primary Biliary Cholangitis

BACKGROUND & AIMS

Gut dysbiosis and myeloid-derived suppressor cells (MDSCs) are implicated in primary biliary cholangitis (PBC) pathogenesis. However, it remains unknown whether gut microbiota or their metabolites can modulate MDSCs homeostasis to rectify immune dysregulation in PBC.

METHODS

We measured fecal short-chain fatty acids levels using targeted gas chromatography-mass spectrometry and analyzed circulating MDSCs using flow cytometry in 2 independent PBC cohorts. Human and murine MDSCs were differentiated in vitro in the presence of butyrate, followed by transcriptomic, epigenetic (CUT&Tag-seq and chromatin immunoprecipitation-quantitative polymerase chain reaction), and metabolic (untargeted liquid chromatography-mass spectrometry, mitochondrial stress test, and isotope tracing) analyses. The in vivo role of butyrate-MDSCs was evaluated in a 2-octynoic acid-bovine serum albumin-induced cholangitis murine model.

RESULTS

Decreased butyrate levels and defective MDSC function were found in patients with incomplete response to ursodeoxycholic acid, compared with those with adequate response. Butyrate induced expansion and suppressive activity of MDSCs in a manner dependent on PPARD-driven fatty acid β-oxidation (FAO). Pharmaceutical inhibition or genetic knockdown of the FAO rate-limiting gene CPT1A abolished the effect of butyrate. Furthermore, butyrate inhibited HDAC3 function, leading to enhanced acetylation of lysine 27 on histone H3 at promoter regions of PPARD and FAO genes in MDSCs. Therapeutically, butyrate administration alleviated immune-mediated cholangitis in mice via MDSCs, and adoptive transfer of butyrate-treated MDSCs also displayed protective efficacy. Importantly, reduced expression of FAO genes and impaired mitochondrial physiology were detected in MDSCs from ursodeoxycholic acid nonresponders, and their impaired suppressive function was restored by butyrate.

CONCLUSIONS

We identify a critical role for butyrate in modulation of MDSC homeostasis by orchestrating epigenetic and metabolic crosstalk, proposing a novel therapeutic strategy for treating PBC.

The potential role of Akkermansia muciniphila in liver health

Akkermansia muciniphila (A. muciniphila) is a 'star strain' that has attracted much attention in recent years. A. muciniphila can effectively regulate host metabolism, significantly affect host immune function, and play an important role in balancing host health and disease. As one of the organs most closely related to the gut (the two can communicate through the hepatic portal vein and bile duct system), liver is widely affected by intestinal microorganisms. A growing body of evidence suggests that A. muciniphila may alleviate liver-related diseases by improving the intestinal barrier, energy metabolism and regulating inflammation through its protein components and metabolites. This paper systematically reviews the key roles of A. muciniphila and its derivatives in maintaining liver health and improving liver disease.

Western diets and chronic diseases

'Westernization', which incorporates industrial, cultural and dietary trends, has paralleled the rise of noncommunicable diseases across the globe. Today, the Western-style diet emerges as a key stimulus for gut microbial vulnerability, chronic inflammation and chronic diseases, affecting mainly the cardiovascular system, systemic metabolism and the gut. Here we review the diet of modern times and evaluate the threat it poses for human health by summarizing recent epidemiological, translational and clinical studies. We discuss the links between diet and disease in the context of obesity and type 2 diabetes, cardiovascular diseases, gut and liver diseases and solid malignancies. We collectively interpret the evidence and its limitations and discuss future challenges and strategies to overcome these. We argue that healthcare professionals and societies must react today to the detrimental effects of the Western diet to bring about sustainable change and improved outcomes in the future.

Let food be your medicine - dietary fiber

Dietary fiber (DF) cannot be digested and absorbed by the digestive tract, nor can it provide the energy needed to be burned for metabolic activities. Therefore, from the 1950s to the 1980s, DF received little attention in nutrition studies. With in-depth research and developments in global nutrition, people have gradually paid attention to the fact that DF occupies an essential position in the structure of nutrition, and it can ensure the healthy development of human beings. As early as 390 B.C., the ancient Greek physician Hippocrates proposed, "Let your food be your medicine, and your medicine be your food". This concept has been more systematically validated in modern scientific research, with numerous epidemiological studies showing that the dietary intake of DF-rich foods such as whole grains, root vegetables, legumes, and fruits has the potential to regulate the balance of the gut microbiota and thereby prevent diseases. However, the crosstalk between different types of DF and the gut microbiota is quite complex, and the effects on the organism vary. In this paper, we discuss research on DF and the gut microbiota and related diseases, aiming to understand the relationship between all three better and provide a reference basis for the risk reduction of related diseases.

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.

Suppression of STK39 weakens the MASLD/MASH process by protecting the intestinal barrier

STK39 is reportedly a critical negative regulator of intestinal barrier. Pharmacological targeting of STK39 is expected to protect the intestinal barrier and thereby weaken metabolic dysfunction-associated steatohepatitis (MASH); Proximal colon biopsy tissues from patients with metabolic dysfunction-associated steatotic liver disease (MASLD) and those without MASLD were analyzed for STK39 expression. Wildtype (WT) mice and systemic STK39 gene knockout (STK39-/-) male mice were fed a normal diet or a high-fat methionine-choline deficient diet (HFMCD) for 8 weeks. The MASH mice were grouped and treated with ZT-1a (a STK39 inhibitor) or vehicle intraperitoneal injection during the procedure of HFMCD induction. Liver and intestinal tissues were collected for further examination; Colon tissues from patients with MASLD exhibited higher levels of STK39 than those from subjects without MASLD. Knockout of STK39 diminished CD68+ Kupffer cells and α-SMA+ hepatic stellate cells infiltration in mouse MASH model. Treatment with ZT-1a also prevented severe steatohepatitis in a mouse MASH model, including milder histological and pathological manifestations (lobular inflammation and fibrosis) in the liver. Interestingly, Inhibition of STK39 had minimal effects on hepatic lipid metabolism. The reduced liver injury observed in mice with STK39 inhibition was linked to significant decreases in mucosal inflammation, tight junction disruption and intestinal epithelial permeability to bacterial endotoxins; Collectively, we have revealed that inhibiting STK39 prevents the progression of MASH by protecting the intestinal epithelial barrier.

Immune landscape of hepatocellular carcinoma: From dysregulation of the immune responses to the potential immunotherapies

Hepatocellular carcinoma (HCC) presents a considerable global health burden due to its late diagnosis and high morbidity. The liver's specific anatomical and physiological features expose it to various antigens, requiring precise immune regulation. To the best of our knowledge, this is the first time that a comprehensive overview of the interactions between the immune system and gut microbiota in the development of HCC, as well as the relevant therapeutic approaches are discussed. Dysregulation of immune compartments within the liver microenvironment drives HCC pathogenesis, characterized by elevated regulatory cells such as regulatory T cells (Tregs), myeloid-derived suppressor cells, and M2 macrophages as well as suppressive molecules, alongside reduced number of effector cells like T cells, natural killer cells, and M1 macrophages. Dysbiosis of gut microbiota also contributes to HCC by disrupting intestinal barrier integrity and triggering overactivated immune responses. Immunotherapy approaches, particularly immune checkpoint inhibitors, have exhibited promise in HCC management, yet adoptive cell therapy and cancer vaccination research are in the early steps with relatively less favorable outcomes. Further understanding of immune dysregulation, gut microbiota involvement, and therapeutic combination strategies are essential for advancing precision immunotherapy in HCC.

Microbial metabolites affect tumor progression, immunity and therapy prediction by reshaping the tumor microenvironment (Review)

Several studies have indicated that the gut microbiome and tumor microbiota may affect tumors. Emerging metabolomics research illustrates the need to examine the variations in microbial metabolite composition between patients with cancer and healthy individuals. Microbial metabolites can impact the progression of tumors and the immune response by influencing a number of mechanisms, including modulation of the immune system, cancer or immune‑related signaling pathways, epigenetic modification of proteins and DNA damage. Microbial metabolites can also alleviate side effects and drug resistance during chemotherapy and immunotherapy, while effectively activating the immune system to exert tumor immunotherapy. Nevertheless, the impact of microbial metabolites on tumor immunity can be both beneficial and harmful, potentially influenced by the concentration of the metabolites or the specific cancer type. The present review summarizes the roles of various microbial metabolites in different solid tumors, alongside their influence on tumor immunity and treatment. Additionally, clinical trials evaluating the therapeutic effects of microbial metabolites or related microbes on patients with cancer have been listed. In summary, studying microbial metabolites, which play a crucial role in the interaction between the microbiota and tumors, could lead to the identification of new supplementary treatments for cancer. This has the potential to improve the effectiveness of cancer treatment and enhance patient prognosis.

Harnessing CD8+ T cell dynamics in hepatitis B virus-associated liver diseases: Insights, therapies and future directions

Hepatitis B virus (HBV) infection playsa significant role in the etiology and progression of liver-relatedpathologies, encompassing chronic hepatitis, fibrosis, cirrhosis, and eventual hepatocellularcarcinoma (HCC). Notably, HBV infection stands as the primary etiologicalfactor driving the development of HCC. Given the significant contribution ofHBV infection to liver diseases, a comprehensive understanding of immunedynamics in the liver microenvironment, spanning chronic HBV infection,fibrosis, cirrhosis, and HCC, is essential. In this review, we focused on thefunctional alterations of CD8+ T cells within the pathogenic livermicroenvironment from HBV infection to HCC. We thoroughly reviewed the roles ofhypoxia, acidic pH, metabolic reprogramming, amino acid deficiency, inhibitory checkpointmolecules, immunosuppressive cytokines, and the gut-liver communication in shapingthe dysfunction of CD8+ T cells in the liver microenvironment. Thesefactors significantly impact the clinical prognosis. Furthermore, we comprehensivelyreviewed CD8+ T cell-based therapy strategies for liver diseases,encompassing HBV infection, fibrosis, cirrhosis, and HCC. Strategies includeimmune checkpoint blockades, metabolic T-cell targeting therapy, therapeuticT-cell vaccination, and adoptive transfer of genetically engineered CD8+ T cells, along with the combined usage of programmed cell death protein-1/programmeddeath ligand-1 (PD-1/PD-L1) inhibitors with mitochondria-targeted antioxidants.Given that targeting CD8+ T cells at various stages of hepatitis Bvirus-induced hepatocellular carcinoma (HBV + HCC) shows promise, we reviewedthe ongoing need for research to elucidate the complex interplay between CD8+ T cells and the liver microenvironment in the progression of HBV infection toHCC. We also discussed personalized treatment regimens, combining therapeuticstrategies and harnessing gut microbiota modulation, which holds potential forenhanced clinical benefits. In conclusion, this review delves into the immunedynamics of CD8+ T cells, microenvironment changes, and therapeuticstrategies within the liver during chronic HBV infection, HCC progression, andrelated liver diseases.

Impact and potential value of immunosenescence on solid gastrointestinal tumors

Solid gastrointestinal tumors often respond poorly to immunotherapy for the complex tumor microenvironment (TME), which is exacerbated by immune system alterations. Immunosenescence is the process of increased diversification of immune genes due to aging and other factors, leading to a decrease in the recognition function of the immune system. This process involves immune organs, immune cells, and the senescence-associated secretory phenotype (SASP). The most fundamental change is DNA damage, resulting in TME remodeling. The main manifestations are worsening inflammation, increased immunosuppressive SASP production, decreased immune cell antitumor activity, and the accumulation of tumor-associated fibroblasts and myeloid-derived suppressor cells, making antitumor therapy less effective. Senotherapy strategies to remove senescent cells and block key senescence processes can have synergistic effects with other treatments. This review focuses on immunoenescence and its impact on the solid TME. We characterize the immunosenescent TME and discuss future directions for antitumor therapies targeting senescence.