Role of Gut Microbiota in Hepatocarcinogenesis. Microorganisms. 2019;7:pii: E121. [PMID: 31060311 PMCID: PMC6560397 DOI: 10.3390/microorganisms7050121]

Exploring the gut microbiome: A potential biomarker for cancer diagnosis, prognosis, and therapy

The gut microbiome, a complex community of trillions of microorganisms in the intestines, is crucial in maintaining human health. Recent advancements in microbiome research have unveiled a compelling link between the gut microbiome and cancer development and progression. Alterations in the composition and function of the gut microbiome, known as dysbiosis, have been implicated in various types of cancer, including, esophageal, liver, colon, pancreatic, and gastrointestinal. However, the specific gut microbial strains associated with the development or progression of cancers in various tissues remain largely unclear. Here, we summarize current research findings on the gut microbiome of multiple cancers. This review aims to identify key gut microbial targets that closely influence cancer development based on current research findings. To accurately evaluate the effectiveness of the gut microbiome as a clinical tool for cancer, further research is needed to explore its potential as a biomarker and therapeutic strategy.

Novel perspectives on the link between obesity and cancer risk: from mechanisms to clinical implications

Existing epidemiologic and clinical studies have demonstrated that obesity is associated with the risk of a variety of cancers. In recent years, an increasing number of experimental and clinical studies have unraveled the complex relationship between obesity and cancer risk and the underlying mechanisms. Obesity-induced abnormalities in immunity and biochemical metabolism, including chronic inflammation, hormonal disorders, dysregulation of adipokines, and microbial dysbiosis, may be important contributors to cancer development and progression. These contributors play different roles in cancer development and progression at different sites. Lifestyle changes, weight loss medications, and bariatric surgery are key approaches for weight-centered, obesity-related cancer prevention. Treatment of obesity-related inflammation and hormonal or metabolic dysregulation with medications has also shown promise in preventing obesity-related cancers. In this review, we summarize the mechanisms through which obesity affects the risk of cancer at different sites and explore intervention strategies for the prevention of obesity-associated cancers, concluding with unresolved questions and future directions regarding the link between obesity and cancer. The aim is to provide valuable theoretical foundations and insights for the in-depth exploration of the complex relationship between obesity and cancer risk and its clinical applications.

Dysregulation in the microbiota by HBV and HCV infection induces an altered cytokine profile in the pathobiome of infection

Viral hepatitis is a public health problem, about 1 million people die due to complications of this viral disease, the etiological agents responsible for inducing cirrhosis and cellular hepatocarcinoma are HBV and HCV, both hepatotropic viruses that cause asymptomatic infection in most cases. The regulation of the microbiota performs many physiological functions, which can induce normal intestinal function and produce essential nutrients for the human body. Metabolites derived from gut microbiota or direct regulation of host immunity and metabolism have been reported to profoundly affect tumorigenesis in liver disease. If the microbiota is unbalanced, both exogenous and symbiotic microorganisms can affect a pathological process. It is well understood that the microbiota plays a role in viral diseases and infections, specifically the hepatic portal pathway has been linked to the gut-liver axis. In HBV and HCV infections, the altered bacterial representatives undergo a state of dysbiosis, with subsequent establishment of the pathobiome with overexpression of taxons such as Bacteroides, Clostridium, Lactobacillus, Enterobacter, and Enterococcus. This dysregulated microbiome induces a microenvironment conducive to the development of hepatic complications in patients with acute and chronic HBV and HCV infection, with subsequent dysregulation of cytokines IFN-α/β, TNF-α, IL-1β, TGF-β, IL-6 and IL-10, which alter the dysfunction and damage of the hepatic portal system. In view of the above, this review aimed to correlate the pathophysiological mechanisms in HBV and HCV infection, the dysregulation of the microbiome in patients infected with HBV and HCV, the most altered cytokines in the microbiome, and the most altered bacterial representatives in the pathobiome of infection.

Insights of gut-liver axis in hepatic diseases: Mechanisms, clinical implications, and therapeutic potentials

With the rising prevalence of chronic liver diseases worldwide, there exists a need to diversify our artillery to incorporate a plethora of diagnostic and therapeutic methods to combat this disease. Currently, the most common causes of liver disease are non-alcoholic fatty liver disease, hepatitis, and alcoholic liver disease. Some of these chronic diseases have the potential to transform into hepatocellular carcinoma with advancing fibrosis. In this review, we analyse the relationship between the gut and liver and their significance in liver disease. This two-way relationship has interesting effects on each other in liver diseases. The gut microbiota, through its metabolites, influences the metabolism in numerous ways. Careful manipulation of its composition can lead to the discovery of numerous therapeutic potentials that can be applied in the treatment of various liver diseases. Numerous cohort studies with a pan-omics approach are required to understand the association between the gut microbiome and hepatic disease progression through which we can identify effective ways to deal with this issue.

Potential Target Metabolites From Gut Microbiota Against Hepatocellular Carcinoma: A Network Pharmacology and Molecular Docking Study

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide, posing significant challenges and economic burdens on healthcare systems. Gut microbiota metabolites have shown promise in cancer treatment, but the specific active metabolites and their key targets remain unclear. This study employed a network pharmacology-based approach to identify potent metabolites of gut microbiota and their key targets. Active metabolites produced by gut microbiota were retrieved using the database gutMGene, and targets associated with these metabolites were identified using the Swiss Target Prediction tool. HCC-related targets were obtained from the GeneCards database, and overlapping targets were selected through a Venn diagram tool. An integrated metabolites-target-pathway network was analyzed to identify active inhibitors against HCC, including p-cresol glucuronide, secoisolariciresinol, glycocholic acid, enterodiol, and citric acid. Molecular docking tests were performed to validate the findings and assess the binding affinity of the metabolites with their target proteins. The study identified AKT1, EGFR, ALB, and TNF genes as potential therapeutic targets against hepatic cancer. The metabolites, p-cresol glucuronide, secoisolariciresinol, glycocholic acid, enterodiol, and citric acid, exhibited significant binding affinity with their respective target proteins. The study also revealed multiple signaling pathways and biological processes associated with the metabolites, demonstrating their preventive effect against HCC. This research utilizes a network pharmacology-based approach to identify potent metabolites of gut microbiota and their key targets for the treatment of HCC. The findings were validated through molecular docking tests, providing a foundation for future studies on anti-HCC metabolites and their mechanisms of action. Furthermore, this study offers insights into the development of novel anti-HCC drugs utilizing gut microbiota metabolites.

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.

Aflatoxin B1-induced liver pyroptosis is mediated by disturbing the gut microbial metabolites: The roles of pipecolic acid and norepinephrine

The disturbed gut microbiota is a key factor in activating the aflatoxin B1 (AFB1)-induced liver pyroptosis by promoting inflammatory hepatic injury; however, the pathogen associated molecular pattern (PAMP) from disturbed gut microbiota and its mechanism in activating liver pyroptosis remain undefined. By transplanting AFB1-originated fecal microbiota and sterile fecal microbial metabolites filtrate, we determined the association of PAMP in AFB1-induced liver pyroptosis. Notably, AFB1-originated sterile fecal microbial metabolites filtrate were more active in triggering liver pyroptosis in mice, as compared to parental fecal microbiota. This result supported a critical role of the metabolic homeostasis of gut microbiota in AFB1-induced liver pyroptosis, rather than an injurious response to direct exposure of AFB1 in liver. Among the gut-microbial metabolites, pipecolic acid and norepinephrine were proposed to bind TLR4 and NLRP3, the upstream proteins of pyroptosis signaling pathway. Besides, the activations of TLR4 and NLRP3 were linearly correlated with the concentrations of pipecolic acid and norepinephrine in the serum of mice. In silenced expression of TLR4 and NLRP3 in HepG2 cells, pipecolic acid or norepinephrine did not able to activate hepatocyte pyroptosis. These results demonstrated the necessity of gut microbial metabolism in sustaining liver homeostasis, as well as the potential to provide new insights into targeted intervention for AFB1 hepatotoxicity.

New studies with stable gastric pentadecapeptide protecting gastrointestinal tract. significance of counteraction of vascular and multiorgan failure of occlusion/occlusion-like syndrome in cytoprotection/organoprotection

Since the early 1990s, when Robert's and Szabo's cytoprotection concept had already been more than one decade old, but still not implemented in therapy, we suggest the stable gastric pentadecapeptide BPC 157 as the most relevant mediator of the cytoprotection concept. Consequently, it can translate stomach and gastrointestinal mucosal maintenance, epithelium, and endothelium cell protection to the therapy of other tissue healing (organoprotection), easily applicable, as native and stable in human gastric juice for more than 24 h. These overwhelm current clinical evidence (i.e., ulcerative colitis, phase II, no side effects, and no lethal dose (LD1) in toxicology studies), as BPC 157 therapy effectively combined various tissue healing and lesions counteraction. BPC 157 cytoprotection relevance and vascular recovery, activation of collateral pathways, membrane stabilizer, eye therapy, wound healing capability, brain-gut and gut-brain functioning, tumor cachexia counteraction, muscle, tendon, ligament, and bone disturbances counteraction, and the heart disturbances, myocardial infarction, heart failure, pulmonary hypertension, arrhythmias, and thrombosis counteraction appeared in the recent reviews. Here, as concept resolution, we review the counteraction of advanced Virchow triad circumstances by activation of the collateral rescuing pathways, depending on injury, activated azygos vein direct blood flow delivery, to counteract occlusion/occlusion-like syndromes starting with the context of alcohol-stomach lesions. Counteraction of major vessel failure (congested inferior caval vein and superior mesenteric vein, collapsed azygos vein, collapsed abdominal aorta) includes counteraction of the brain (intracerebral and intraventricular hemorrhage), heart (congestion, severe arrhythmias), lung (hemorrhage), and congestion and lesions in the liver, kidney, and gastrointestinal tract, intracranial (superior sagittal sinus), portal and caval hypertension, aortal hypotension, and thrombosis, peripherally and centrally.

Optimal probiotic combinations for treating nonalcoholic fatty liver disease: A systematic review and network meta-analysis

BACKGROUND

Probiotic administration is a promising therapy for improving conditions in NAFLD patients. This network meta-analysis aimed to compare and estimate the relative effects of probiotic interventions and identify the optimal probiotic species for the treatment of NAFLD (Nonalcoholic fatty liver disease) patients.

METHODS

The PubMed, Web of Science, Embase, and Cochrane databases were searched from inception to 29 January 2024 to identify RCTs that were published in English. The GRADE framework was used to assess the quality of evidence contributing to each network estimate.

RESULTS

A total of 35 RCTs involving 2212 NAFLD patients were included in the analysis. For primary outcomes, Lactobacillus + Bifidobacterium + Streptococcus exhibited the highest probability of being the finest probiotic combination in terms of enhancing acceptability as well as reducing AST (SMD: -1.95 95% CI: -2.90, -0.99), ALT (SMD = -1.67, 95% CI: -2.48, -0.85), and GGT levels (SMD = -2.17, 95% CI: -3.27, -1.06). In terms of the secondary outcomes, Lactobacillus + Bifidobacterium + Streptococcus was also the best probiotic combination for reducing BMI (SMD = -0.45, 95% CI: -0.86, -0.04), LDL levels (SMD = -0.45, 95% CI: -0.87, -0.02), TC levels (SMD = -1.09, 95% CI: -1.89, -0.29), and TNF-α levels (SMD = -1.73, 95% CI: -2.72, -0.74).

CONCLUSION

This network meta-analysis revealed that Lactobacillus + Bifidobacterium + Streptococcus may be the most effective probiotic combination for the treatment of liver enzymes, lipid profiles, and inflammation factors. These findings can be used to guide the development of a probiotics-based treatment guideline for NAFLD since there are few direct comparisons between different therapies.

Probiotics-A Promising Novel Therapeutic Approach in the Management of Chronic Liver Diseases

An increased incidence of liver diseases has been observed in recent years and is associated with gut dysbiosis, which causes bacterial infection, intestinal permeability, and further leads to disease-related complications. Probiotics, active microbial strains, are gaining more clinical importance due to their beneficial effect in the management of many diseases, including liver diseases. Clinical scenarios show strong evidence that probiotics have efficacy in treating liver diseases due to their ability to improve epithelial barrier function, prevent bacterial translocation, and boost the immune system. Moreover, probiotics survive both bile and gastric acid to reach the gut and exert their health benefit. Evidence shows that probiotics are a promising approach to prevent several complications in clinical practice. Herein, we discuss the recent evidence, challenges, and appropriate use of probiotics in managing advanced liver diseases, which may have an impact on future therapeutic strategies. Furthermore, the superior effect of strain-specific probiotics and their efficacy and safety in managing liver diseases are discussed.

Aflatoxin B1 exposure causes splenic pyroptosis by disturbing the gut microbiota-immune axis

Aflatoxin B1 (AFB1) causes serious immunotoxicity and has attracted considerable attention owing to its high sensitivity and common chemical-viral interactions in living organisms. However, the sensitivity of different species to AFB1 widely varies, which cannot be explained by the different metabolism in species. The gut microbiota plays a crucial role in the immune system, but the interaction of the microbiota with AFB1-induced immunotoxicity still needs to be determined. Our results indicated that AFB1 exposure disrupted the structure of the gut microbiota and damaged the gut barrier, which caused translocation of microbiota metabolites, lipopolysaccharides, to the spleen. Subsequently, pyroptosis of the spleen was activated. Interestingly, AFB1 exposure had little effect on the splenic pyroptosis of pseudo-germfree mice (antibiotic mixtures eliminated their gut microbiota, ABX). Then, fecal microbiota transplant (FMT) and sterile fecal filtrate (SFF) were employed to validate the function of the gut microbiota and its metabolites in AFB1-induced splenic pyroptosis. The AFB1-disrupted microbiota and its metabolites significantly promoted splenic pyroptosis, which was worse than that in control mice. Overall, AFB1-induced splenic pyroptosis is associated with the gut microbiota and its metabolites, which was further demonstrated by FMT and SFF. The mechanism of AFB1-induced splenic pyroptosis was explored for the first time, which paves a new way for preventing and treating the immunotoxicity from mycotoxins by regulating the gut microbiota.

Efficacy of immunotherapy in hepatocellular carcinoma: Does liver disease etiology have a role?

The systemic treatment of hepatocellular carcinoma (HCC) is changing rapidly. After a decade of tyrosine kinase inhibitors (TKIs), as the only therapeutic option for the treatment of advanced HCC, in the last few years several phase III trials demonstrated the efficacy of immune checkpoint inhibitors (ICIs). The combination of the anti-PD-L1 atezolizumab and the anti-vascular endothelial growth factor (VEGF) bevacizumab demonstrated the superiority over sorafenib and currently represents the standard of care treatment for advanced HCC. In addition, the combination of durvalumab (an anti-PD-L1) and tremelimumab (an anti-CTLA4) proved to be superior to sorafenib, and in the same trial durvalumab monotherapy showed non-inferiority compared to sorafenib. However, early reports suggest an influence of HCC etiology in modulating the response to these drugs. In particular, a lower effectiveness of ICIs has been suggested in patients with non-viral HCC (in particular non-alcoholic fatty liver disease). Nevertheless, randomized controlled trials available to date have not been stratified for etiology and data suggesting a possible impact of etiology in the outcome of patients managed with ICIs derive from subgroup not pre-specified analyses. In this review, we aim to examine the potential impact of HCC etiology on the response to immunotherapy regimens for HCC.

Fructooligosaccharides and galactooligosaccharides improve hepatic steatosis via gut microbiota-brain axis modulation

Studies have shown that gut dysbiosis is associated with the steatotic liver disease associated with metabolic dysfunction (MALSD) and its severity. This study evaluated the effects of two commercially available prebiotics fructooligosaccharides (FOS) and galactooligosaccharides(GOS) on hepatic adipogenesis, inflammation, and gut microbiota in high-fat diet-induced MALSD. The results indicated that FOS and GOS effectively reduced insulin resistance, hyperglycaemia, triglyceridemia, cholesterolaemia, and IL-1β serum levels. Moreover, FOS and GOS modulated the lipogenic (SREBP-1c, ACC, and FAS) and lipolytic (ATGL) signalling pathways, and reduced inflammatory markers such as p-NFκB-65, IL-6, iNOS, COX-2, TNF-α, IL-1β, and nitrotyrosine. FOS and GOS also enhanced the abundance of acetate producers' bacteria Bacteroides acidifaciens and Bacteroides dorei. FOS and GOS also induced positive POMC/GPR43 neurons at the arcuate nucleus, indicating hypothalamic signalling modulation. Our results suggest that FOS and GOS attenuated MALSD by reducing the hepatic lipogenic pathways and intestinal permeability through the gut microbiota-brain axis.

Past, present, and future of chemically induced hepatocarcinogenesis rodent models: Perspectives concerning classic and new cancer hallmarks

Hepatocellular carcinoma (HCC), the main primary liver cancer, accounts for 5 % of all incident cases and 8.4 % of all cancer-related deaths worldwide. HCC displays a spectrum of environmental risk factors (viral chronic infections, aflatoxin exposure, alcoholic- and nonalcoholic fatty liver diseases) that result in molecular complexity and heterogeneity, contributing to a rising epidemiological burden, poor prognosis, and non-satisfactory treatment options. The emergence of HCC (i.e., hepatocarcinogenesis) is a multistep and complex process that addresses many (epi)genetic alterations and phenotypic traits, the so-called cancer hallmarks. "Polymorphic microbiomes", "epigenetic reprogramming", "senescent cells" and "unlocking phenotypic plasticity" are trending hallmarks/enabling features in cancer biology. As the main molecular drivers of HCC are still undruggable, chemically induced in vivo models of hepatocarcinogenesis are useful tools in preclinical research. Thus, this narrative review aimed at recapitulating the basic features of chemically induced rodent models of hepatocarcinogenesis, eliciting their permanent translational value regarding the "classic" and the "new" cancer hallmarks/enabling features. We gathered state-of-art preclinical evidence on non-cirrhotic, inflammation-, alcoholic liver disease- and nonalcoholic fatty liver-associated HCC models, demonstrating that these bioassays indeed express the recently added hallmarks, as well as reflect the interplay between classical and new cancer traits. Our review demonstrated that these protocols remain valuable for translational preclinical application, as they recapitulate trending features of cancer science. Further "omics-based" approaches are warranted while multimodel investigations are encouraged in order to avoid "model-biased" responses.

The Role of Gut Microbiome in Hepatocellular Carcinoma: A Systematic Review

Gut microbiome dysbiosis is common in patients with chronic liver diseases such as hepatocellular carcinoma (HCC) and plays an essential role in developing, diagnosing, and treating HCC. The purpose of this systematic review, which was carried out following the Preferred Reporting Items for Systematic Review and Meta-analyses 2020 guidelines, is to determine the role of the gut microbiome in the pathogenesis, diagnosis, and treatment of HCC. We collected and reviewed articles, including clinical trials, literature reviews, case-control studies, cross-sectional studies, cohort studies, systematic reviews, and meta-analyses, published between May 30, 2013, and May 30, 2023. The databases used to collect these articles included PubMed, Cochrane Library, Google Scholar, and ScienceDirect. After applying appropriate filters, a total of 2,969 studies were identified. They were further screened and subjected to quality assessment tools which finally yielded 17 studies included in this systematic review. This systematic review provides information regarding the gut-liver axis and the relationship between gut microbiome dysbiosis and HCC.

Aflatoxin B1 Induces Inflammatory Liver Injury via Gut Microbiota in Mice

Aflatoxin B₁ (AFB₁), a potent food-borne hepatocarcinogen, is the most toxic aflatoxin that induces liver injury in humans and animals. Species-specific sensitivities of aflatoxins cannot be fully explained by differences in the metabolism of AFB₁ between animal species. The gut microbiota are critical in inflammatory liver injury, but it remains to reveal the role of gut microbiota in AFB₁-induced liver injury. Here, mice were gavaged with AFB₁ for 28 days. Then, the modulation of gut microbiota, colonic barrier, and liver pyroptosis and inflammation were analyzed. To further verify the direct role of gut microbiota in AFB₁-induced liver injury, mice were treated with antibiotic mixtures (ABXs) to deplete the microbiota, and fecal microbiota transplantation (FMT) was conducted. The treatment of AFB₁ in mice altered gut microbiota composition, such as increasing the relative abundance of Bacteroides, Parabacteroides, and Lactobacillus, inducing colonic barrier dysfunction and promoting liver pyroptosis. In ABX-treated mice, AFB₁ had little effect on the colonic barrier and liver pyroptosis. Notably, after FMT, in which the mice were colonized with gut microbiota from AFB₁-treated mice, colonic barrier dysfunction, and liver pyroptosis and inflammation were obliviously identified. We proposed that the gut microbiota directly participated in AFB₁-induced liver pyroptosis and inflammation. These results provide new insights into the mechanisms of AFB₁ hepatotoxicity and pave a window for new targeted interventions to prevent or reduce AFB₁ hepatotoxicity.

Exploring the potential impact of probiotic use on drug metabolism and efficacy

Probiotics are frequently consumed as functional food and widely used as dietary supplements, but are also recommended in treating or preventing various gastrointestinal diseases. Therefore, their co-administration with other drugs is sometimes unavoidable or even compulsory. Recent technological developments in the pharmaceutical industry permitted the development of novel drug-delivery systems for probiotics, allowing their addition to the therapy of severely ill patients. Literature data regarding the changes that probiotics could impose on the efficacy or safety of chronic medication is scarce. In this context, the present paper aims to review probiotics currently recommended by the international medical community, to evaluate the relationship between gut microbiota and various pathologies with high impact worldwide and, most importantly, to assess the literature reports concerning the ability of probiotics to influence the pharmacokinetics/pharmacodynamics of some widely used drugs, especially for those with narrow therapeutic indexes. A better understanding of the potential influence of probiotics on drug metabolism, efficacy and safety could contribute to improving therapy management, facilitating individualized therapy and updating treatment guidelines.

The role of gut microbiota in liver regeneration

The liver has unique regeneration potential, which ensures the continuous dependence of the human body on hepatic functions. As the composition and function of gut microbiota has been gradually elucidated, the vital role of gut microbiota in liver regeneration through gut-liver axis has recently been accepted. In the process of liver regeneration, gut microbiota composition is changed. Moreover, gut microbiota can contribute to the regulation of the liver immune microenvironment, thereby modulating the release of inflammatory factors including IL-6, TNF-α, HGF, IFN-γ and TGF-β, which involve in different phases of liver regeneration. And previous research have demonstrated that through enterohepatic circulation, bile acids (BAs), lipopolysaccharide, short-chain fatty acids and other metabolites of gut microbiota associate with liver and may promote liver regeneration through various pathways. In this perspective, by summarizing gut microbiota-derived signaling pathways that promote liver regeneration, we unveil the role of gut microbiota in liver regeneration and provide feasible strategies to promote liver regeneration by altering gut microbiota composition.

The Role of the Microbiota Gut-Liver Axis during HCV Chronic Infection: A Schematic Overview

Hepatitis C virus (HCV) still represents one of the most important worldwide health care problems. Since 2011, direct-acting antiviral (DAA) drugs have increased the number of people who have achieved a sustained virological response (SVR). Even if the program to eradicate HCV by 2030 is still ongoing, the SARS-CoV-2 pandemic has created a delay due to the reallocation of public health resources. HCV is characterized by high genetic variability and is responsible for hepatic and extra-hepatic diseases. Depending on the HCV genotype/subtype and comorbidities of patients, tailored treatment is necessary. Recently, it has been shown that liver damage impacts gut microbiota, altering the microbial community (dysbiosis) during persistent viral replication. An increasing number of studies are trying to clarify the role of the gut-liver axis during HCV chronic infection. DAA therapy, by restoring the gut microbiota equilibrium, seems to improve liver disease progression in both naïve and treated HCV-positive patients. In this review, we aim to discuss a snapshot of selected peer-reviewed papers concerning the interplay between HCV and the gut-liver axis.

Food and Gut Microbiota-Derived Metabolites in Nonalcoholic Fatty Liver Disease

Diet and lifestyle are crucial factors that influence the susceptibility of humans to nonalcoholic fatty liver disease (NAFLD). Personalized diet patterns chronically affect the composition and activity of microbiota in the human gut; consequently, nutrition-related dysbiosis exacerbates NAFLD via the gut–liver axis. Recent advances in diagnostic technology for gut microbes and microbiota-derived metabolites have led to advances in the diagnosis, treatment, and prognosis of NAFLD. Microbiota-derived metabolites, including tryptophan, short-chain fatty acid, fat, fructose, or bile acid, regulate the pathophysiology of NAFLD. The microbiota metabolize nutrients, and metabolites are closely related to the development of NAFLD. In this review, we discuss the influence of nutrients, gut microbes, their corresponding metabolites, and metabolism in the pathogenesis of NAFLD.

Microbiome-Based Metabolic Therapeutic Approaches in Alcoholic Liver Disease

Alcohol consumption is a global healthcare problem. Chronic alcohol consumption generates a wide spectrum of hepatic lesions, the most characteristic of which are steatosis, hepatitis, fibrosis, and cirrhosis. Alcoholic liver diseases (ALD) refer to liver damage and metabolomic changes caused by excessive alcohol intake. ALD present several clinical stages of severity found in liver metabolisms. With increased alcohol consumption, the gut microbiome promotes a leaky gut, metabolic dysfunction, oxidative stress, liver inflammation, and hepatocellular injury. Much attention has focused on ALD, such as alcoholic fatty liver (AFL), alcoholic steatohepatitis (ASH), alcoholic cirrhosis (AC), hepatocellular carcinoma (HCC), a partnership that reflects the metabolomic significance. Here, we report on the global function of inflammation, inhibition, oxidative stress, and reactive oxygen species (ROS) mechanisms in the liver biology framework. In this tutorial review, we hypothetically revisit therapeutic gut microbiota-derived alcoholic oxidative stress, liver inflammation, inflammatory cytokines, and metabolic regulation. We summarize the perspective of microbial therapy of genes, gut microbes, and metabolic role in ALD. The end stage is liver transplantation or death. This review may inspire a summary of the gut microbial genes, critical inflammatory molecules, oxidative stress, and metabolic routes, which will offer future promising therapeutic compounds in ALD.

Hepatocellular Carcinoma: Understanding the Inflammatory Implications of the Microbiome

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

The Activity of Prebiotics and Probiotics in Hepatogastrointestinal Disorders and Diseases Associated with Metabolic Syndrome

The components of metabolic syndrome (MetS) and hepatogastrointestinal diseases are widespread worldwide, since many factors associated with lifestyle and diet influence their development and correlation. Due to these growing health problems, it is necessary to search for effective alternatives for prevention or adjuvants in treating them. The positive impact of regulated microbiota on health is known; however, states of dysbiosis are closely related to the development of the conditions mentioned above. Therefore, the role of prebiotics, probiotics, or symbiotic complexes has been extensively evaluated; the results are favorable, showing that they play a crucial role in the regulation of the immune system, the metabolism of carbohydrates and lipids, and the biotransformation of bile acids, as well as the modulation of their central receptors FXR and TGR-5, which also have essential immunomodulatory and metabolic activities. It has also been observed that they can benefit the host by displacing pathogenic species, improving the dysbiosis state in MetS. Current studies have reported that paraprobiotics (dead or inactive probiotics) or postbiotics (metabolites generated by active probiotics) also benefit hepatogastrointestinal health.

Viral hepatitis and hepatocellular carcinoma: From molecular pathways to the role of clinical surveillance and antiviral treatment

Hepatocellular carcinoma (HCC) is a global health challenge. Due to the high prevalence in low-income countries, hepatitis B virus (HBV) and hepatitis C virus infections remain the main risk factors for HCC occurrence, despite the increasing frequencies of non-viral etiologies. In addition, hepatitis D virus coinfection increases the oncogenic risk in patients with HBV infection. The molecular processes underlying HCC development are complex and various, either independent from liver disease etiology or etiology-related. The reciprocal interlinkage among non-viral and viral risk factors, the damaged cellular microenvironment, the dysregulation of the immune system and the alteration of gut-liver-axis are known to participate in liver cancer induction and progression. Oncogenic mechanisms and pathways change throughout the natural history of viral hepatitis with the worsening of liver fibrosis. The high risk of cancer incidence in chronic viral hepatitis infected patients compared to other liver disease etiologies makes it necessary to implement a proper surveillance, both through clinical-biochemical scores and periodic ultrasound assessment. This review aims to outline viral and microenvironmental factors contributing to HCC occurrence in patients with chronic viral hepatitis and to point out the importance of surveillance programs recommended by international guidelines to promote early diagnosis of HCC.

The Role of the Microbiome in Gastroentero-Pancreatic Neuroendocrine Neoplasms (GEP-NENs)

Gut microbiome balance plays a key role in human health and maintains gut barrier integrity. Dysbiosis, referring to impaired gut microbiome, is linked to a variety of diseases, including cancers, through modulation of the inflammatory process. Most studies concentrated on adenocarcinoma of different sites with very limited information on gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). In this study, we have analyzed the gut microbiome (both fungal and bacterial communities) in patients with metastatic GEP-NENs. Fecal samples were collected and compared with matched healthy control samples using logistic regression distances utilizing R package MatchIt (version 4.2.0, Daniel E. Ho, Stanford, California). We examined differences in microbiome profiles between GEP-NENs and control samples using small subunit (SSU) rRNA (16S), ITS1, ITS4 genomic regions for their ability to accurately characterize bacterial and fungal communities. We correlated the results with different behavioral and dietary habits, and tumor features including differentiation, grade, primary site, and therapeutic response. All tests are two-sided and p-values ≤ 0.05 were considered statistically significant. Gut samples of 34 patients (12 males, 22 females, median age 64 years) with metastatic GEP-NENs (22 small bowel, 10 pancreatic, 1 gall bladder, and 1 unknown primary) were analyzed. Twenty-nine patients had well differentiated GEP-neuroendocrine tumors (GEP-NETs), (G1 = 14, G2 = 12, G3 = 3) and five patients had poorly differentiated GEP-neuroendocrine carcinomas (GEP-NECs). Patients with GEP-NENs had significantly decreased bacterial species and increased fungi (notably Candida species, Ascomycota, and species belonging to saccharomycetes) compared to controls. Patients with GEP-NECs had significantly enriched populations of specific bacteria and fungi (such as Enterobacter hormaechei, Bacteroides fragilis and Trichosporon asahii) compared to those with GEP-NETs (p = 0.048, 0.0022 and 0.034, respectively). In addition, higher grade GEP-NETs were associated with significantly higher Bacteroides fragilis (p = 0.022), and Eggerthella lenta (p = 0.00018) species compared to lower grade tumors. There were substantial differences associated with dietary habits and therapeutic responses. This is the first study to analyze the role of the microbiome environment in patients with GEP-NENs. There were significant differences between GEP-NETs and GEP-NECs, supporting the role of the gut microbiome in the pathogenesis of these two distinct entities.

Targeting Wnt/β-Catenin Pathways in Primary Liver Tumours: From Microenvironment Signaling to Therapeutic Agents

Primary liver cancers (PLCs) are steadily increasing in incidence and mortality in the world. They have a poor prognosis due to their silent nature, late discovery and resistance to common chemotherapy. At present, there are limited treatment alternatives, and the understanding of PLC molecular aspects is essential to develop more efficient drugs and therapeutic surgical and loco-regional strategies. A clear causal link with liver damage, inflammation, and regeneration has been found in the occurrence of PLC over the last few decades. Physiologically, Wingless/It (Wnt)-β-catenin signaling plays a key role in liver development, metabolic zonation and regeneration. Loss of functional homeostasis of this pathway appears to be a major driver of carcinogenesis in the liver parenchyma. In the hepatic microenvironment, molecular deregulations that exceed the Wnt signaling biological capacity can induce tumor initiation and progression. Indeed, somatic mutations are identified in key components of canonical and non-canonical Wnt signaling and in PLCs and precancerous lesions. In this review, the altered functions of Wnt/β-catenin signaling are considered in human PLCs, with emphasis on hepatocellular carcinomas (HCC), cholangiocarcinomas (CCA) and hepatoblastomas (HB). Based on recent literature, we also focused on liver cancerogenesis through Wnt deregulation. An overview of preclinical and clinical studies on approved and experimental drugs, targeting the Wnt/β-catenin cascade in PLCs, is proposed. In addition, the clinical implication of molecule inhibitors that have been shown to possess activity against the Wnt pathway in association with conventional surgical and loco-regional therapies are reviewed.

Gut Microbiota Targeted Approach in the Management of Chronic Liver Diseases

The liver is directly connected to the intestines through the portal vein, which enables the gut microbiota and gut-derived products to influence liver health. There is accumulating evidence of decreased gut flora diversity and alcohol sensitivity in patients with various chronic liver diseases, including non-alcoholic/alcoholic liver disease, chronic hepatitis virus infection, primary sclerosing cholangitis and liver cirrhosis. Increased intestinal mucosal permeability and decline in barrier function were also found in these patients. Followed by bacteria translocation and endotoxin uptake, these will lead to systemic inflammation. Specific microbiota and microbiota-derived metabolites are altered in various chronic liver diseases studies, but the complex interaction between the gut microbiota and liver is missing. This review article discussed the bidirectional relationship between the gut and the liver, and explained the mechanisms of how the gut microbiota ecosystem alteration affects the pathogenesis of chronic liver diseases. We presented gut-microbiota targeted interventions that could be the new promising method to manage chronic liver diseases.

Roles of Microbiota in Cancer: From Tumor Development to Treatment

Cancer as a second leading cause of death arises from multifactorial pathology. The association of microbiota and their products with various pathologic conditions including cancer is receiving significant attention over the past few years. Mounting evidence showed that human microbiota is an emerging target in tumor onset, progression, prevention, and even diagnosis. Accordingly, modulating this composition might influence the response to tumor therapy and therapeutic resistance as well. Through this review, one could conceive of complex interaction between the microbiome and cancer in either positive or negative manner by which may hold potential for finding novel preventive and therapeutic strategies against cancer.

Interactive relationship between Trp metabolites and gut microbiota: The impact on human pathology of disease

Tryptophan (Trp), an α-amino acid, is the precursor of serotonin (5-hydroxytryptamine, 5-HT), which is involved in a variety of features of metabolic function and human nutrition. Evidence highlights the role of Trp metabolites (exclusively 5-HT) in the gastrointestinal (GI) tract; however, the mechanisms of action involved in the release of 5-HT in the GI tract are still unknown. Considering the fact that variations of 5-HT may facilitate the growth of certain GI disorders, gaining a better understanding of the function and release of 5-HT in the GI tract would be beneficial. Additionally, investigating Trp metabolism may clarify the relationship between Trp and gut microbiota. It is believed that other metabolites of Trp (mostly that of the kynurenine pathway) may play a significant role in controlling gut microbiota function. In this review, we have attempted to summarize the current research investigating the relationship of gut microbiota, Trp, and 5-HT metabolism (with particular attention paid to their metabolite type, as well as a discussion of the research methods used in each study). Taking together, regarding the role that Trp/5-HT plays in a range of physical and mental diseases, the gut bacterial types, as well as the related disorders, have been exclusively considered.

Gut Microbiome in Non-Alcoholic Fatty Liver Disease: From Mechanisms to Therapeutic Role

Non-alcoholic fatty liver disease (NAFLD) is considered to be a significant health threat globally, and has attracted growing concern in the research field of liver diseases. NAFLD comprises multifarious fatty degenerative disorders in the liver, including simple steatosis, steatohepatitis and fibrosis. The fundamental pathophysiology of NAFLD is complex and multifactor-driven. In addition to viruses, metabolic syndrome and alcohol, evidence has recently indicated that the microbiome is related to the development and progression of NAFLD. In this review, we summarize the possible microbiota-based therapeutic approaches and highlight the importance of establishing the diagnosis of NAFLD through the different spectra of the disease via the gut–liver axis.

Molecular Immune Mechanism of Intestinal Microbiota and Their Metabolites in the Occurrence and Development of Liver Cancer

Intestinal microorganisms are closely associated with immunity, metabolism, and inflammation, and play an important role in health and diseases such as inflammatory bowel disease, diabetes, cardiovascular disease, Parkinson’s disease, and cancer. Liver cancer is one of the most fatal cancers in humans. Most of liver cancers are slowly transformed from viral hepatitis, alcoholic liver disease, and non-alcoholic fatty liver disease. However, the relationship between intestinal microbiota and their metabolites, including short-chain fatty acids, bile acids, indoles, and ethanol, and liver cancer remains unclear. Here, we summarize the molecular immune mechanism of intestinal microbiota and their metabolites in the occurrence and development of liver cancer and reveal the important role of the microbiota-gut-liver axis in liver cancer. In addition, we describe how the intestinal flora can be balanced by antibiotics, probiotics, postbiotics, and fecal bacteria transplantation to improve the treatment of liver cancer. This review describes the immunomolecular mechanism of intestinal microbiota and their metabolites in the occurrence and development of hepatic cancer and provides theoretical evidence support for future clinical practice.

COL1A1 Gene Expression in Hepatitis B Virus (HBV) Related Hepatocellular Carcinoma (HCC) Egyptian's Patients

Introduction:

Collagens are the most abundant proteins in the human body, accounting for one-third of total proteins. Over the last few years, accumulated evidence have indicated that some collagens are differentially expressed in cancer. The aim of the study was to assess COL1A1 gene expression as a novel marker for the progression of hepatitis B cirrhosis into hepatocellular carcinoma.

Methods:

This cohort study included 348 subjects and was conducted between May 2018 and June 2019. Subjects were divided into 4 groups: group1 included HBV positive hepatocellular carcinoma patients “HCC” (n= 87), group II included HBV positive patients with liver cirrhosis “LC” (n = 87), group III included chronic hepatitis B patients with neither HCC nor cirrhosis “ C-HBV” (n = 87) and group IV consisted of healthy volunteers as controls (n = 87). Fasting venous blood samples (10 ml) were collected from each participant in this study and were used for assessment of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, albumin and alfa-fetoprotein (AFP). Another portion of blood was collected in 2 vacutainer tubes containing EDTA, one for Complete blood count and the other for gene expression of COL1A1.

Results:

The gene expression of collagen was 6.9 ± 8.8 in group 1 (HBV positive hepatocellular carcinoma patients) and this was a significant increase in comparison with the other groups. In group 2 (HBV positive patients with liver cirrhosis), the gene expression (collagen) was 3.7±1.5 and it was significantly increased when compared with group 4 (healthy volunteers).

Conclusion:

COL1A1 gene expression can be used as an indicator of the progression of hepatitis B cirrhosis into hepatocellular carcinoma.

Critical biomarkers of hepatocellular carcinoma in body fluids and gut microbiota

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer and one of the major causes of cancer-related death. The development of specific non-invasive or diagnostic markers from blood, urine and feces may represent a valuable tool for detecting HCC at an early stage. Biomarkers are considered novel potential targets for therapeutic intervention. It helps in the prediction of prognosis or recurrence of HCC, and also assist in the selection of appropriate treatment modality. We summarize the most relevant existing data about various biomarkers that play a key role in the progression of HCC.

Lactobacillus lactis and Pediococcus pentosaceus-driven reprogramming of gut microbiome and metabolome ameliorates the progression of non-alcoholic fatty liver disease

BACKGROUND

Although microbioa-based therapies have shown putative effects on the treatment of non-alcoholic fatty liver disease (NAFLD), it is not clear how microbiota-derived metabolites contribute to the prevention of NAFLD. We explored the metabolomic signature of Lactobacillus lactis and Pediococcus pentosaceus in NAFLD mice and its association in NAFLD patients.

METHODS

We used Western diet-induced NAFLD mice, and L. lactis and P. pentosaceus were administered to animals in the drinking water at a concentration of 109 CFU/g for 8 weeks. NAFLD severity was determined based on liver/body weight, pathology and biochemistry markers. Caecal samples were collected for the metagenomics by 16S rRNA sequencing. Metabolite profiles were obtained from caecum, liver and serum. Human stool samples (healthy control [n = 22] and NAFLD patients [n = 23]) were collected to investigate clinical reproducibility for microbiota-derived metabolites signature and metabolomics biomarker.

RESULTS

L. lactis and P. pentosaceus supplementation effectively normalized weight ratio, NAFLD activity score, biochemical markers, cytokines and gut-tight junction. While faecal microbiota varied according to the different treatments, key metabolic features including short chain fatty acids (SCFAs), bile acids (BAs) and tryptophan metabolites were analogously restored by both probiotic supplementations. The protective effects of indole compounds were validated with in vitro and in vivo models, including anti-inflammatory effects. The metabolomic signatures were replicated in NAFLD patients, accompanied by the comparable levels of Firmicutes/Bacteroidetes ratio, which was significantly higher (4.3) compared with control (0.6). Besides, the consequent biomarker panel with six stool metabolites (indole, BAs, and SCFAs) showed 0.922 (area under the curve) in the diagnosis of NAFLD.

CONCLUSIONS

NAFLD progression was robustly associated with metabolic dys-regulations in the SCFAs, bile acid and indole compounds, and NAFLD can be accurately diagnosed using the metabolites. L. lactis and P. pentosaceus ameliorate NAFLD progression by modulating gut metagenomic and metabolic environment, particularly tryptophan pathway, of the gut-liver axis.

Hepatocellular Carcinoma in Non-Alcoholic Fatty Liver Disease: From Epidemiology to Diagnostic Approach

Non-alcoholic fatty liver disease (NAFLD) is becoming the leading cause of liver morbidity worldwide and, as such, represents the pathogenic background for the increasing incidence of hepatocellular carcinoma (HCC). The annual incidence of NAFLD-related HCC is expected to increase by 45-130% by 2030. Diabetes mellitus is the most important risk factor for HCC development in NAFLD, with the risk further increased when associated with other metabolic traits, such as obesity, arterial hypertension and dyslipidemia. The highest risk of HCC exists in patients with advanced fibrosis or cirrhosis, although 20-50% of HCC cases arise in NAFLD patients with an absence of cirrhosis. This calls for further investigation of the pathogenic mechanisms that are involved in hepatocarcinogenesis, including genetics, metabolomics, the influence of the gut microbiota and immunological responses. Early identification of patients with or at risk of NAFLD is of utmost importance to improve outcomes. As NAFLD is highly prevalent in the community, the identification of cases should rely upon simple demographic and clinical characteristics. Once identified, these patients should then be evaluated for the presence of advanced fibrosis or cirrhosis and subsequently enter HCC surveillance programs if appropriate. A significant problem is the early recognition of non-cirrhotic NAFLD patients who will develop HCC, where new biomarkers and scores are potential solutions to tackle this issue.

Therapeutic implications of probiotics in microbiota dysbiosis: A special reference to the liver and oral cancers

The microbiota plays an important role in maintaining the body's homeostasis. Imbalance in the microbiota is referred to as microbiota dysbiosis. Microbiota dysbiosis leads to pro-inflammatory immune response and progression of cancer- one of the leading causes of mortality globally. Accumulating evidence suggest the role of microbiota-dysbiosis in the liver and oral carcinogenesis and the therapeutic role of probiotic strains against these diseases. Probiotics are active microbial strains that have recently gained clinical importance due to their beneficial effects on the human body associated with the prevention and treatment of different diseases, including cancer. Multiple researchers have reported the use of probiotic strains in the modulation of microbiota and immune responses for cancer prevention and management. Clinical trials have also highlighted the efficacy of probiotic strains in reducing the side effects of microbiota dysbiosis related to cancer. In this context, the probiotic-mediated modulation to reverse microbiota dysbiosis is now considered one of the possible novel strategies for cancer prevention and management. In this article, we review the association between microbiota dysbiosis and liver/oral cancer. This review highlights the research advances on the anti-cancer activity of probiotic strains and their metabolites in the management of liver and oral cancers.

The Gut-Liver Axis in Chronic Liver Disease: A Macrophage Perspective

Chronic liver disease (CLD) is a growing health concern which accounts for two million deaths per year. Obesity, alcohol overconsumption, and progressive cholestasis are commonly characterized by persistent low-grade inflammation and advancing fibrosis, which form the basis for development of end-stage liver disease complications, including hepatocellular carcinoma. CLD pathophysiology extends to the intestinal tract and is characterized by intestinal dysbiosis, bile acid dysregulation, and gut barrier disruption. In addition, macrophages are key players in CLD progression and intestinal barrier breakdown. Emerging studies are unveiling macrophage heterogeneity and driving factors of their plasticity in health and disease. To date, in-depth investigation of how gut-liver axis disruption impacts the hepatic and intestinal macrophage pool in CLD pathogenesis is scarce. In this review, we give an overview of the role of intestinal and hepatic macrophages in homeostasis and gut-liver axis disruption in progressive stages of CLD.

Prospects and Challenges of the Study of Anti-Glycan Antibodies and Microbiota for the Monitoring of Gastrointestinal Cancer

Over the past decades, a large amount of data has been accumulated in various subfields of glycobiology. However, much clinically relevant data and many tools are still not widely used in medicine. Synthetic glycoconjugates with the known structure of glycans are an accurate tool for the study of glycan-binding proteins. We used polyacrylamide glycoconjugates (PGs) including PGs with tumour-associated glycans (TAGs) in immunoassays to assess the prognostic potential of the serum level of anti-glycan antibodies (AG Abs) in gastrointestinal cancer patients and found an association of AG Abs with survival. The specificity of affinity-isolated AG Abs was investigated using synthetic and natural glycoconjugates. AG Abs showed mainly a low specificity to tumour-associated and tumour-derived mucins; therefore, the protective role of the examined circulating AG Abs against cancer remains a challenge. In this review, our findings are analysed and discussed in the context of the contribution of bacteria to the AG Abs stimulus and cancer progression. Examples of the influence of pathogenic bacteria colonising tumours on cancer progression and patient survival through mechanisms of interaction with tumours and dysregulated immune response are considered. The possibilities and problems of the integrative study of AG Abs and the microbiome using high-performance technologies are discussed.

Intestinal Permeability Is a Mechanical Rheostat in the Pathogenesis of Liver Cirrhosis

Recent studies have suggested that an alteration in the gut microbiota and their products, particularly endotoxins derived from Gram-negative bacteria, may play a major role in the pathogenesis of liver diseases. Gut dysbiosis caused by a high-fat diet and alcohol consumption induces increased intestinal permeability, which means higher translocation of bacteria and their products and components, including endotoxins, the so-called "leaky gut". Clinical studies have found that plasma endotoxin levels are elevated in patients with chronic liver diseases, including alcoholic liver disease and nonalcoholic liver disease. A decrease in commensal nonpathogenic bacteria including Ruminococaceae and Lactobacillus and an overgrowth of pathogenic bacteria such as Bacteroidaceae and Enterobacteriaceae are observed in cirrhotic patients. The decreased diversity of the gut microbiota in cirrhotic patients before liver transplantation is also related to a higher incidence of post-transplant infections and cognitive impairment. The exposure to endotoxins activates macrophages via Toll-like receptor 4 (TLR4), leading to a greater production of proinflammatory cytokines and chemokines including tumor necrosis factor-alpha, interleukin (IL)-6, and IL-8, which play key roles in the progression of liver diseases. TLR4 is a major receptor activated by the binding of endotoxins in macrophages, and its downstream signal induces proinflammatory cytokines. The expression of TLR4 is also observed in nonimmune cells in the liver, such as hepatic stellate cells, which play a crucial role in the progression of liver fibrosis that develops into hepatocarcinogenesis, suggesting the importance of the interaction between endotoxemia and TLR4 signaling as a target for preventing liver disease progression. In this review, we summarize the findings for the role of gut-derived endotoxemia underlying the progression of liver pathogenesis.

Gut Microbiota in Liver Disease: What Do We Know and What Do We Not Know?

The gut and the liver have a bidirectional communication via the biliary system and the portal vein. The intestinal microbiota and microbial products play an important role for modulating liver diseases such as alcohol-associated liver disease, non-alcoholic fatty liver disease and steatohepatitis, and cholestatic liver diseases. Here, we review the role of the gut microbiota and its products for the pathogenesis and therapy of chronic liver diseases.

The intestinal microbiota contributes to the growth and physiological state of muscle tissue in piglets

Although the importance of the intestinal microbiota in host growth and health is well known, the relationship between microbiota colonization and muscle development is unclear. In this study, the direct causal effects of the colonization of gut microorganisms on the muscle tissue of piglets were investigated. The body weight and lean mass of germ-free (GF) piglets were approximately 40% lower than those of normal piglets. The deletion of the intestinal microbiota led to weakened muscle function and a reduction in myogenic regulatory proteins, such as MyoG and MyoD, in GF piglets. In addition, the blinded IGF1/AKT/mTOR pathway in GF piglets caused muscle atrophy and autophagy, which were characterized by the high expression of Murf-1 and KLF15. Gut microbiota introduced to GF piglets via fecal microbiota transplantation not only colonized the gut but also partially restored muscle growth and development. Furthermore, the proportion of slow-twitch muscle fibers was lower in the muscle of GF piglets, which was caused by the reduced short-chain fatty acid content in the circulation and impaired mitochondrial function in muscle. Collectively, these findings suggest that the growth, development and function of skeletal muscle in animals are mediated by the intestinal microbiota.

A novel therapeutic strategy for hepatocellular carcinoma: Immunomodulatory mechanisms of selenium and/or selenoproteins on a shift towards anti-cancer

Selenium (Se) is an essential trace chemical element that is widely distributed worldwide. Se exerts its immunomodulatory and nutritional activities in the human body in the form of selenoproteins. Se has increasingly appeared as a potential trace element associated with many human diseases, including hepatocellular carcinoma (HCC). Recently, increasing evidence has suggested that Se and selenoproteins exert their immunomodulatory effects on HCC by regulating the molecules of oxidative stress, inflammation, immune response, cell proliferation and growth, angiogenesis, signaling pathways, apoptosis, and other processes in vitro cell studies and in vivo animal studies. Se concentrations are generally low in tissues of patients with HCC, such as blood, serum, scalp hair, and toenail. However, Se concentrations were higher in HCC patient tissues after Se supplementation than before supplementation. This review summarizes the significant relationship between Se and HCC, and details the role of Se as a novel immunomodulatory or immunotherapeutic approach against HCC.

Gut Microbiota as Potential Biomarker and/or Therapeutic Target to Improve the Management of Cancer: Focus on Colibactin-Producing Escherichia coli in Colorectal Cancer

Simple Summary

Gut microbiota is emerging as new diagnostic and prognostic marker and/or therapeutic target to improve the management of cancer. This review aims to summarize microbial signatures that have been associated with digestive and other cancers. We report the clinical relevance of these microbial markers to predict the response to cancer therapy. Among these biomarkers, colibactin-producing E. coli are prevalent in the colonic mucosa of patients with colorectal cancer and they promote colorectal carcinogenesis in several pre-clinical models. Here we discuss the promising use of colibactin-producing E. coli as a new predictive factor and a therapeutic target in colon cancer management.

Abstract

The gut microbiota is crucial for physiological development and immunological homeostasis. Alterations of this microbial community called dysbiosis, have been associated with cancers such colorectal cancers (CRC). The pro-carcinogenic potential of this dysbiotic microbiota has been demonstrated in the colon. Recently the role of the microbiota in the efficacy of anti-tumor therapeutic strategies has been described in digestive cancers and in other cancers (e.g., melanoma and sarcoma). Different bacterial species seem to be implicated in these mechanisms: F. nucleatum, B. fragilis, and colibactin-associated E. coli (CoPEC). CoPEC bacteria are prevalent in the colonic mucosa of patients with CRC and they promote colorectal carcinogenesis in susceptible mouse models of CRC. In this review, we report preclinical and clinical data that suggest that CoPEC could be a new factor predictive of poor outcomes that could be used to improve cancer management. Moreover, we describe the possibility of using these bacteria as new therapeutic targets.

Gut Microbiota: Influence on Carcinogenesis and Modulation Strategies by Drug Delivery Systems to Improve Cancer Therapy

Gut microbiota have close interactions with the host. It can affect cancer progression and the outcomes of cancer therapy, including chemotherapy, immunotherapy, and radiotherapy. Therefore, approaches toward the modulation of gut microbiota will enhance cancer prevention and treatment. Modern drug delivery systems (DDS) are emerging as rational and promising tools for microbiota intervention. These delivery systems have compensated for the obstacles associated with traditional treatments. In this review, the essential roles of gut microbiota in carcinogenesis, cancer progression, and various cancer therapies are first introduced. Next, advances in DDS that are aimed at enhancing the efficacy of cancer therapy by modulating or engineering gut microbiota are highlighted. Finally, the challenges and opportunities associated with the application of DDS targeting gut microbiota for cancer prevention and treatment are briefly discussed.

Metabolic Spectrum of Liver Failure in Type 2 Diabetes and Obesity: From NAFLD to NASH to HCC

Liver disease is the spectrum of liver damage ranging from simple steatosis called as nonalcoholic fatty liver disease (NAFLD) to hepatocellular carcinoma (HCC). Clinically, NAFLD and type 2 diabetes coexist. Type 2 diabetes contributes to biological processes driving the severity of NAFLD, the primary cause for development of chronic liver diseases. In the last 20 years, the rate of non-viral NAFLD/NASH-derived HCC has been increasing rapidly. As there are currently no suitable drugs for treatment of NAFLD and NASH, a class of thiazolidinediones (TZDs) drugs for the treatment of type 2 diabetes is sometimes used to improve liver failure despite the risk of side effects. Therefore, diagnosis, prevention, and treatment of the development and progression of NAFLD and NASH are important issues. In this review, we will discuss the pathogenesis of NAFLD/NASH and NAFLD/NASH-derived HCC and the current promising pharmacological therapies of NAFLD/NASH. Further, we will provide insights into "adipose-derived adipokines" and "liver-derived hepatokines" as diagnostic and therapeutic targets from NAFLD to HCC.

Role of microbiota-derived short-chain fatty acids in cancer development and prevention

Following cancer, cells in a particular tissue can no longer respond to the factors involved in controlling cell survival, differentiation, proliferation, and death. In recent years, it has been indicated that alterations in the gut microbiota components, intestinal epithelium, and host immune system are associated with cancer incidence. Also, it has been demonstrated that the short-chain fatty acids (SCFAs) generated by gut microbiota are vitally crucial in cell homeostasis as they contribute to the modulation of histone deacetylases (HDACs), resulting effected cell attachment, immune cell immigration, cytokine production, chemotaxis, and the programmed cell death. Therefore, the manipulation of SCFA levels in the intestinal tract by alterations in the microbiota structure can be potentially taken into consideration for cancer treatment/prevention. In the current study, we will explain the most recent findings on the detrimental or protective roles of SFCA (particularly butyrate, propionate, and acetate) in several cancers, including bladder, colon, breast, stomach, liver, lung, pancreas, and prostate cancers.

Intestinal Microbiota and Liver Diseases: Insights into Therapeutic Use of Traditional Chinese Medicine

Liver disease is a leading cause of global morbidity and mortality, for which inflammation, alcohol use, lipid metabolic disorders, disturbance to bile acid metabolism, and endotoxins are common risk factors. Traditional Chinese Medicine (TCM) with its "holistic approach" is widely used throughout the world as a complementary, alternative therapy, due to its clinical efficacy and reduced side effects compared with conventional medicines. However, due to a lack of reliable scientific evidence, the role of TCM in the prevention and treatment of liver disease remains unclear. Over recent years, with the rapid development of high-throughput sequencing, 16S rRNA detection, and bioinformatics methodology, it has been gradually recognized that the regulation of intestinal microbiota by TCM can play a substantial role in the treatment of liver disease. To better understand how TCM regulates the intestinal microbiota and suppresses liver disease, we have reviewed and analyzed the results of existing studies and summarized the relationship and risk factors between intestinal microbiota and liver disease. The present review summarizes the related mechanisms by which TCM affects the composition and metabolites of the intestinal microbiome.

Mechanisms by Which Probiotic Bacteria Attenuate the Risk of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and the second leading cause of cancer-related deaths worldwide. Chronic infections with hepatitis B virus (HBV) and hepatitis C virus (HCV), alcoholic liver disease (ALD), and non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) are the major extrinsic risk factors of HCC development. Genetic background is pivotal in HCC pathogenesis, and both germline mutations and single nucleotide polymorphism (SNP) are intrinsic risk factors of HCC. These HCC risk factors predispose to hepatic injury and subsequent activation of fibrogenesis that progresses into cirrhosis and HCC. Probiotic bacteria can mitigate HCC risk by modulating host gut microbiota (GM) to promote growth of beneficial microbes and inhibit HCC-associated dysbiosis, thus preventing pathogen-associated molecular patterns (PAMPs)-mediated hepatic inflammation. Probiotics have antiviral activities against HBV and HCV infections, ameliorate obesity and risk of NAFLD/NASH, and their antioxidant, anti-proliferative, anti-angiogenic, and anti-metastatic effects can prevent the HCC pathogenesis. Probiotics also upregulate the expression of tumor suppressor genes and downregulate oncogene expression. Moreover, metabolites generated by probiotics through degradation of dietary phytochemicals may mitigate the risk of HCC development. These multiple anticancer mechanisms illustrate the potential of probiotics as an adjuvant strategy for HCC risk management and treatment.

The role and underlying mechanism of miR-1299 in cancer

A type of evolutionarily conserved, noncoding, small, endogenous, single-stranded RNA, miRNAs are widely distributed in eukaryotes, where they participate in various biological processes as critical regulatory molecules. miR-1299 has mainly been investigated in cancers. miR-1299 is a tumor suppressor that regulates the expression of its target genes, activating or inhibiting the transcription of genes regulating biological activities including cell proliferation, migration, survival and programmed cell death. miR-1299 has become a hotspot in research of disease mechanisms and biomarkers; elucidation of the regulatory roles of miR-1299 in tumorigenesis, proliferation, apoptosis, invasion, migration and angiogenesis may provide a new perspective for understanding its biological functions as a tumor suppressor.

As key regulatory molecules, microRNAs participate in various biological processes and have become a widespread research focus. This article discusses how the microRNA miR-1299 plays a role as a tumor suppressor and participates in the regulation of tumor pathogenesis. We provide an overview of the role of miR-1299 in tumor diseases and discuss the pathogenesis and regulation mechanisms of miR-1299 in different specific cancers.

Serum proteome profiling provides a deep understanding of the 'gut-liver axis' in relation to liver injury and regeneration

The gut-liver axis is one of the major contributors to the transport of products from the intestine or intestinal microbes with the progression of liver regeneration. However, the influence of proteins from the hepatic portal vein (HPV), the bridge of enterohepatic circulation, on liver regeneration is unclear. For first time, we applied a quantitative proteomics approach to characterize the molecular pathology of the HPV sera of mice with antibiotic-induced intestinal flora disorder during acute liver injury. The biological processes of lipid metabolism and wound healing were enriched in the HPV of mice with intestinal flora disorder, whereas energy metabolism, liver regeneration, and cytoskeletal processes were downregulated. Moreover, 95 and 35 proteins potentially promoting or inhibiting liver regeneration, respectively, were identified in HPV serum. Our findings will be beneficial to liver donors during liver transplantation.