Gut-liver axis in liver cirrhosis: How to manage leaky gut and endotoxemia

Efficacy of probiotics on improvement of health outcomes in cirrhotic liver disease patients: A systematic review and meta-analysis of randomised controlled trials

Liver cirrhosis is a chronic condition of the liver and is the 14th most common cause of death around the world; yet it remains an incurable disease. Probiotics have gained significant popularity as a potential treatment option for liver cirrhosis.

METHODS

A systematic review and meta-analysis was conducted to assess the effects of probiotics on liver cirrhosis. PubMed, Scopus, Cochrane Central Register for Controlled Trials (CENTRAL) and ProQuest Dissertation and Thesis were searched from 2000 to January 2024 for studies that evaluated the effects of probiotics on a variety of outcomes of liver disease.

RESULTS

A total of 22 randomised controlled trial studies were included in the meta-analysis. Probiotics significantly decreased Gamma-glutamyl transferase (effect size: 0.307, p = 0.024, 95% CI [-0.572, -0.040]) and Aspartate aminotransferase (p = 0.013, 95% CI [-17.927, -2.128]). Significant reduction in serum ammonia levels (effect size = -1.093, p = 0.000, 95% CI [-1.764, -0.423]) and endotoxin levels (effect size = -0.961, p = 0.000, 95% CI [-1.537, -0.385]) were also found.

SUMMARY

Overall probiotics could be recommended as a potential adjunct therapy for patients with cirrhosis, as they appear to have some benefit in improving liver function, and are well tolerated with minimal adverse effects. More comprehensive research with larger sample sizes is recommended to understand more about the widespread effects of probiotic use.

The dose-dependent mechanism behind the protective effect of lentinan against acute alcoholic liver injury via proliferating intestinal probiotics

Acute alcoholic liver injury (AALI) is a widespread disease that can develop into hepatitis, liver fibrosis, and cirrhosis. In severe cases, it can be life-threatening, while drug treatment presents various side effects. This study characterized the structure of natural lentinan (LNT) from the Qinba Mountain area and investigated the protective mechanism of different LNT doses (100 mg kg-1, 200 mg kg-1, and 400 mg kg-1) on AALI. The results showed that LNT was a glucose-dominated pyran polysaccharide with a triple-helical structure and a molecular weight (Mw) of 7.56 × 106 Da. An AALI mouse model showed that all the LNT doses protected liver function, reduced hepatic steatosis, alleviated oxidative stress and inflammatory response, and stimulated probiotic proliferation. Low-dose LNT increased anti-oxidant-associated beneficial bacteria, medium-dose LNT improved liver swelling and promoted anti-oxidant-associated probiotics, and high-dose LNT increased the probiotics that helped protect liver function and anti-oxidant and anti-inflammatory properties. All the LNT doses inhibited pathogenic growth, including Oscillospiraceae, Weeksellaceae, Streptococcaceae, Akkermansiaceae, Morganellaceae, and Proteus. These results indicated that the protective effect of LNT against AALI was mediated by the proliferation of various intestinal probiotics and was related to the consumption doses. These findings offer new strategies for comprehensively utilizing Lentinula edodes from the Qinba Mountain area and preventing AALI using natural food-based substances.

Akkermansia muciniphila in the small intestine improves liver fibrosis in a murine liver cirrhosis model

Recent evidence indicates that liver cirrhosis (LC) is a reversible condition, but there is no established intervention against liver fibrosis. Although the gut microbiota is considered involved in the pathogenesis of LC, the underlying mechanisms remain unclear. Although the antibiotic, rifaximin (RFX), is effective for hepatic encephalopathy (HE) with LC, the impact of RFX on intestinal bacteria is unknown. We investigated the bacterial compositions along the GI tract under RFX treatment using a murine LC model. RFX improved liver fibrosis and hyperammonemia and altered the bacterial composition in the small intestine. The efficacy of RFX was associated with increases in specific bacterial genera, including Akkermansia. Administration of a commensal strain of Akkermansia muciniphila improved liver fibrosis and hyperammonemia with changing bacterial composition in the small intestine. This study proposed a new concept "small intestine-liver axis" in the pathophysiology of LC and oral A. muciniphila administration is a promising microbial intervention.

Unraveling the mechanisms of hepatogenous diabetes and its therapeutic perspectives

The review focused mainly on the pathogenesis of hepatogenous diabetes (HD) in liver cirrhosis (LC). This review reveals parallels between the mechanisms of metabolic dysfunction observed in LC and type II diabetes (T2DM), suggesting a shared pathway leading to HD. It underscores the role of insulin in HD pathogenesis, highlighting key factors such as insulin signaling, glucose metabolism, insulin resistance (IR), and the influence of adipocytes. Furthermore, the impact of adipose tissue accumulation, fatty acid metabolism, and pro-inflammatory cytokines like Tumor necrosis factor-α (TNF-α) on IR are discussed in the context of HD. Altered signaling pathways, disruptions in the endocrine system, liver inflammation, changes in muscle mass and composition, and modifications to the gut microbiota collectively contribute to the complex interplay linking cirrhosis and HD. This study highlights how important it is to identify and treat this complex condition in cirrhotic patients by thoroughly analyzing the link between cirrhosis, IR, and HD. It also emphasizes the vitality of targeted interventions. Cellular and molecular investigations into IR have revealed potential therapeutic targets for managing and preventing HD.

Gut-related molecules as potential biomarkers in patients with decompensated cirrhosis

INTRODUCTION AND OBJECTIVES

Microbial translocation contributes to cirrhosis progression and complications. This study aims to investigate whether molecules related to intestinal permeability or microbial translocation can serve as prognostic biomarkers in patients with decompensated cirrhosis.

MATERIALS AND METHODS

We prospectively evaluated hospitalized patients with decompensated cirrhosis for liver function, complications during hospitalization, in-hospital mortality, composite outcomes of in-hospital mortality and complications, 12-month mortality, and survival rates. Blood samples were collected upon admission, and 1,3 beta-d-glucan, zonulin, calprotectin, and lipopolysaccharide-binding protein were measured using commercial kits.

RESULTS

Ninety-one patients with decompensated cirrhosis were enrolled. The mean age was 58 ± 12 years; 57% were male. The three main cirrhosis etiologies were hepatitis C (35%), alcohol (25%), and non-alcoholic steatohepatitis (17%). In terms of liver function, 52% were Child C, and 68% had model for end-stage liver disease ≥15. The in-hospital and one-year mortality rates were 31% and 57%, respectively. Child-Pugh, 1,3 beta-glucan, and model for end-stage liver disease were positively correlated; zonulin was associated with complications during hospitalization (acute kidney injury) and composite outcomes, and calprotectin was associated with all outcomes except 12-month mortality.

CONCLUSIONS

Serum calprotectin and zonulin levels emerge as noninvasive prognostic biomarkers for potentially unfavorable outcomes in patients with decompensated cirrhosis.

Intestinal and hepatic benefits of BBR-EVO on DSS-induced experimental colitis in mice

Ulcerative colitis (UC), characterized by disrupted intestinal barrier integrity and chronic inflammation, was modeled in mice via dextran sulfate sodium (DSS) induction. This study explored the therapeutic potential of berberine-evodiamine (BBR-EVO), bioactive components of the traditional Chinese medicine Yulian decoction, in DSS colitis. BBR-EVO intervention ameliorated weight loss, diarrhea, colonic shortening, and histopathological damage in colitic mice. The substance increased antioxidant activity while reducing high levels of pro-inflammatory cytokines in the colon, including as TNF-α, IL-1β, and IL-6. BBR-EVO inhibited the DSS-induced decrease in the tight junction proteins ZO-1 and occludin, according to immunohistochemistry. 16S rRNA sequencing demonstrated BBR-EVO partially attenuated DSS-elicited intestinal dysbiosis, reducing opportunistic pathogens and restoring diminished beneficial taxa. Critically, BBR-EVO alleviated secondary hepatic injury in colitic mice, mitigating immune cell infiltration, oxidative stress, cytokine production, and ultrastructural damage, likely by beneficially modulating gut-liver crosstalk. This study reveals BBR-EVO, derived from a traditional Chinese medicine, confers multi-target protective effects in experimental colitis and associated hepatic pathology, warranting further evaluation as a potential therapy for inflammatory bowel diseases like UC. The mechanisms may involve simultaneous augmentation of intestinal barrier integrity, inhibition of inflammation, microbiota regulation, and gut-liver axis optimization.

Therapeutic potential of rifaximin in liver diseases

Rifaximin, derived from rifamycin, is a broad-spectrum antibiotic by inhibiting bacterial RNA synthesis. Rifaximin has a very low intestinal absorption and exerts its antimicrobial activity primarily in the intestinal tract. It regulates the gut microbiota with limited side effects systemically. Rifaximin has been recommended for the treatment of hepatic encephalopathy but some studies shed light on its medicinal effects in many other diseases. For instance, rifaximin may suppress the progression of liver fibrosis and its related complications, and ameliorate metabolic dysfunction-associated steatotic liver disease and alcohol-associated liver disease, etc. Rifaximin can also mediate anti-inflammation, antiproliferation, and proapoptotic events by activating pregnane X receptor, which is efficious in cancers such as colon cancer. In addition, some investigations have shown rifaximin may play a therapeutic role in various autoimmune and neurological disorders. However, these findings still need more real-world practices and in-depth investigations to obtain more precise indications and fully elucidate the multifaceted potentials of rifaximin.

From Cirrhosis to the Dysbiosis (A Loop of Cure or Complications?)

Gut dysbiosis and liver cirrhosis are two corelated complications that highly disturbs the metabolism of a normal human body. Liver cirrhosis is scarring of the hepatic tissue and gut dysbiosis is the imbalance in the microbiome of the gut. Gut dysbiosis in cirrhosis occurs due to increased permeability of the intestinal membrane which might induce immune responses and damage the normal functioning of the body. Dysbiosis can cause liver damage from cirrhosis and can further lead to liver failure by hepatocellular carcinoma. In this review we discuss if eubiosis can revert the poorly functioning cirrhotic liver to normal functioning state? A normal microbiome converts various liver products into usable forms that regulates the overgrowth of microbiome in the gut. The imbalance caused by dysbiosis retards the normal functioning of liver and increases the complications. To correct this dysbiosis, measures like use of antibiotics with probiotics and prebiotics are used. This correction of the gut microbiome serves as a ray of hope to recover from this chronic illness. In case of alcohol induced liver cirrhosis, intervention of microbes can possibly be helpful in modulating the addiction as well as associated complications like depression as microbes are known to produce and consume neurotransmitters that are involved in alcohol addiction. Hence a correction of gut liver brain axis using microbiome can be a milestone achieved not only for treatment of liver cirrhosis but also for helping alcohol addicts quit and live a healthy or at least a near healthy life.

p16High immune cell - controlled disease tolerance as a broad defense and healthspan extending strategy

The ability of an organism to overcome infectious diseases has traditionally been linked to killing invading pathogens. Accumulating evidence, however, indicates that, apart from restricting pathogen loads, organismal survival is coupled to an additional yet poorly understood mechanism called disease tolerance. Here we report that p16High immune cells play a key role in establishing disease tolerance. We found that the FDA-approved BNT162b2 mRNA COVID-19 vaccine is a potent and rapid inducer of p16High immune subsets both in mice and humans. In turn, p16High immune cells were indispensable for counteracting different lethal conditions, including LPS-induced sepsis, acute SARS-CoV-2 infection and ionizing irradiation. Mechanistically, we propose that activation of TLR7 or a low physiological activity of STING is sufficient to induce p16High immune subset that, in turn, establishes a low adenosine environment and disease tolerance. Furthermore, containing these signals within a beneficial range by deleting MDA5 that appeared sufficient to maintain a low activity of STING, induces p16High immune cells and delays organ deterioration upon aging with improved healthspan. Our data highlight the beneficial role of p16High immune subsets in establishing a low adenosine environment and disease tolerance.

Prebiotics, probiotics, synbiotics and postbiotics to adolescents in metabolic syndrome

The prevalence of childhood and adolescent obesity has globally reached alarming dimensions and many adolescents affected by obesity already present one or more obesity-related comorbidities. In recent years, emerging evidence supporting the role of gut microbiota in the pathophysiology of metabolic diseases has been reported and the use of prebiotics, probiotics, synbiotics and postbiotics as a strategy to manipulate gut microbiota has become popular. The aim of this review is to explore the relationship between gut microbiota and metabolic syndrome in adolescents and to discuss the potential use of prebiotics, probiotics, synbiotics and postbiotics for the prevention and treatment of this clinical picture in adolescence. According to the most recent literature, prebiotics, probiotics and synbiotics have no clear effect on MetS, but a possible modulation of anthropometric parameters has been observed after synbiotic supplementation. Only one study has examined the role of postbiotics in alleviating metabolic complications in children with obesity but not in adolescents. More extensive research is needed to support the conclusions drawn so far and to develop effective microbiome-based interventions that may help improving the quality of life of children and adolescents exposed to the increasing prevalence of MetS.

The gut-liver axis in fatty liver disease: role played by natural products

Fatty liver disease, a condition characterized by fatty degeneration of the liver, mainly classified as non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD), has become a leading cause of cirrhosis, liver cancer and death. The gut-liver axis is the bidirectional relationship between the gut and its microbiota and its liver. The liver can communicate with the gut through the bile ducts, while the portal vein transports the products of the gut flora to the liver. The intestinal flora and its metabolites directly and indirectly regulate hepatic gene expression, leading to an imbalance in the gut-liver axis and thus contributing to the development of liver disease. Utilizing natural products for the prevention and treatment of various metabolic diseases is a prevalent practice, and it is anticipated to represent the forthcoming trend in the development of drugs for combating NAFLD/ALD. This paper discusses the mechanism of the enterohepatic axis in fatty liver, summarizes the important role of plant metabolites in natural products in fatty liver treatment by regulating the enterohepatic axis, and provides a theoretical basis for the subsequent development of new drugs and clinical research.

Effects of Lactobacillus paracasei N1115 on gut microbial imbalance and liver function in patients with hepatitis B-related cirrhosis

BACKGROUND

Hepatitis B cirrhosis (HBC) is a chronic disease characterized by irreversible diffuse liver damage and aggravated by intestinal microbial imbalance and metabolic dysfunction. Although the relationship between certain single probiotics and HBC has been explored, the impact of the complex ready-to-eat Lactobacillus paracasei N1115 (LP N1115) supplement on patients with HBC has not been determined.

AIM

To compare the changes in the microbiota, inflammatory factor levels, and liver function before and after probiotic treatment in HBC patients.

METHODS

This study included 160 HBC patients diagnosed at the General Hospital of Ningxia Medical University between October 2018 and December 2020. Patients were randomly divided into an intervention group that received LP N1115 supplementation and routine treatment and a control group that received routine treatment only. Fecal samples were collected at the onset and conclusion of the 12-wk intervention period. The structure of the intestinal microbiota and the levels of serological indicators, such as liver function and inflammatory factors, were assessed.

RESULTS

Following LP N1115 intervention, the intestinal microbial diversity significantly increased in the intervention group (P < 0.05), and the structure of the intestinal microbiota was characterized by an increase in the proportions of probiotic microbes and a reduction in harmful bacteria. Additionally, the intervention group demonstrated notable improvements in liver function indices and significantly lower levels of inflammatory factors (P < 0.05).

CONCLUSION

LP N1115 is a promising treatment for ameliorating intestinal microbial imbalance in HBC patients by modulating the structure of the intestinal microbiota, improving liver function, and reducing inflammatory factor levels.

Endotoxemia and Platelets: 2 Players of Intrahepatic Microthrombosis in NAFLD

Gut dysbiosis-related intestinal barrier dysfunction with increased translocation of bacterial products such as lipopolysaccharide (LPS) into systemic circulation is emerging as pathogenic factor of nonalcoholic fatty liver disease (NAFLD). Experimental and clinical studies suggested a potential role of LPS as a trigger eliciting in situ liver inflammation upon interaction with its receptor toll-like receptor 4. Also, LPS has been reported to prime platelets to respond to the common agonists indicating that it behaves as a prothrombotic molecule. Of note, recent studies suggested platelet-related intrahepatic thrombosis triggered by LPS as a mechanism implicated in the process of liver inflammation. This review describes: 1) the impact of gut barrier dysfunction and endotoxemia in the process of NAFLD; 2) the relationship between endotoxemia and platelet activation in NAFLD; 3) clinical evidence for the use of antiplatelet drugs in NAFLD/nonalcoholic steatohepatitis patients; and 4) the potential therapeutic approach to modulate endotoxemia and eventually platelet activation.

Lactobacillus plantarum and Bifidobacterium longum Alleviate Liver Injury and Fibrosis in Mice by Regulating NF-κB and AMPK Signaling

In a preliminary study, live biotherapeutic products (LBPs) Lactobacillus plantarum LC27 and Bifidobacterium longum LC67 inhibited the secretion of alanine transaminase (ALT) and aspartate transaminase (AST) in LPS-stimulated HepG2 cells, while Escherichia coli K1 (Ec) increased ALT and ALT secretion. Therefore, we examined the effects of LC27 and LC67 on LPS-induced liver injury and fibrosis in mice and the correlation between their biomarkers in cell and animal experiments. Orally administered LC27 or LC67 significantly decreased blood ALT, AST, γ-glutamyl transferase (γGTP), TNF-α, triglyceride (TG), total cholesterol (TCh), total bile acid, and LPS levels, liver TNF-α, toll-like receptor-4 gene (Tlr4), α-smooth muscle actin (αSMA), and collagen-1 expression and αSMA+GFAP+ and NF-κB+F4/80+ cell populations, and colonic Tlr4, TNF-α, and IL-6 expression and NF-κB-positive cell population in LPS-treated mice. Furthermore, they increased AMPKa phosphorylation in the liver and colon. However, Ec increased the expression of TNF-α and IL-6 in blood, liver, and colon. The suppression of LPS-stimulated ALT and AST secretion in HepG2 cells by LBPs was positively correlated with their ameliorating effects on LPS-induced blood γGTP, ALT, and AST levels and liver αSMA and collagen-1 expression in mice. Based on these findings, LC27 and LC67 may improve liver injury and fibrosis by regulating NF-κB and AMPK signaling pathway and a protocol that can assay the inhibitory activity of LBPs on LPS-induced ALT and AST secretion in HepG2 may be useful for guessing their antihepatitic effects in the in vivo experiments.

Gut dysbiosis-related thrombosis in inflammatory bowel disease: Potential disease mechanisms and emerging therapeutic strategies

Patients with inflammatory bowel disease (IBD) have an increased risk of developing venous thromboembolic events, which have a considerable impact on morbidity and mortality. Chronic inflammation plays a crucial role in the pathogenesis of thrombotic events in patients with IBD. However, many unresolved questions remain, particularly regarding the mechanisms that determine the persistent inflammatory state independent of disease activity. This review explored the role of gut microbiota dysbiosis and intestinal barrier dysfunction, which are considered distinctive features of IBD, in determining pro-thrombotic tendencies. Gut-derived endotoxemia due to the translocation of bacterial lipopolysaccharides (LPS) from the intestine to the bloodstream and the bacterial metabolite trimethylamine-N-oxide (TMAO) are the most important molecules involved in gut dysbiosis-related thrombosis. The pathogenic prothrombotic pathways linked to LPS and TMAO have been discussed. Finally, we present emerging therapeutic approaches that can help reduce LPS-mediated endotoxemia and TMAO, such as restoring intestinal eubiosis, normalizing intestinal barrier function, and counterbalancing the effects of LPS and TMAO.

Comparison of Inflammatory Cytokine Levels in Hepatic and Jugular Veins of Patients with Cirrhosis

Background

Systemic inflammation with elevated inflammatory cytokines is a hallmark in patients with cirrhosis and the main driver of decompensation. There is insufficient data on whether inflammatory cytokine levels differ between hepatic and jugular veins, which may have implications for further immunological studies.

Methods

Blood from the hepatic and jugular veins of 40 patients with cirrhosis was collected during hepatic venous pressure gradient (HVPG) measurements. Serum levels of 13 inflammatory cytokines (IL-1β, Int-α2, Int-γ, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IL-18, IL-23, and IL-33) were quantified by cytometric bead array.

Results

Cytokine levels of IFN-α2, IFN-γ, TNF-α, IL-6, IL-8, IL-10, IL-17A, IL-18, IL-23, and IL-33 were significantly elevated in patients with decompensated cirrhosis compared to patients with compensated cirrhosis. When comparing patients with clinically significant portal hypertension (CSPH, HVPG ≥ 10 mmHg) to patients without CSPH, there were significantly enhanced serum levels of IL-6 and IL-18 in the former group. There was no significant difference between cytokine serum levels between blood obtained from the jugular versus hepatic veins. Even in subgroup analyses stratified for an early cirrhosis stage (Child-Pugh (CP) A) or more decompensated stages (CP B/C), cytokine levels were similar.

Conclusion

Cytokine levels increase with decompensation and increasing portal hypertension in patients with cirrhosis. There is no relevant difference in cytokine levels between hepatic and jugular blood in patients with cirrhosis.

Potential contribution of the gut microbiota to the development of portal vein thrombosis in liver cirrhosis

Background

Portal vein thrombosis (PVT) is a serious complication of liver cirrhosis (LC) and is closely related to gut homeostasis. The study aimed to investigate the composition of gut microbiota and its putative role in PVT development in LC.

Methods

33 patients with LC admitted between January 2022 and December 2022 were enrolled in this study. Based on imaging findings, they were categorized into LC without PVT (n = 21) and LC with PVT (n = 12) groups. Fecal samples were collected from each participant and underwent 16S rDNA sequencing.

Results

D-Dimer and platelet elevations were the main clinical features of LC with PVT. The alpha and beta diversity of the gut microbiota in LC with PVT group was found to be significantly higher compared to the control group. The structure of the gut microbiota was significantly different between the two groups. Based on LEfSe data, the genera Akkermansia, Eubacterium hallii group, Fusicatenibacter, and Anaerostipes were enriched in the LC with PVT, while Enterococcus, Weissella, Bacteroides, and Subdoligranulum were enriched in those of the LC subjects. Changes in microbiota structure result in significant differences in gut microbiota metabolism between the two groups. Altered levels of the microbiota genera were shown to be correlated with coagulation factor parameters. In animal experiments, the addition of Bacteroides reversed the CCl4-induced PVT.

Conclusion

Liver cirrhosis with PVT led to a disorder in the gut microbiota, which was characterized by an increase in pathogenic bacteria and a decrease in beneficial bacteria. Furthermore, modulating the gut microbiota, especially Bacteroides, may be a promising therapeutic approach to reduce the progression of PVT in LC.

Probiotic management and inflammatory factors as a novel treatment in cirrhosis: A systematic review and meta-analysis

The interaction between intestinal microecological dysregulation, altered inflammatory factors, and cirrhosis is unclear. The aim of this systematic review and meta-analysis was to synthesize the results of previous studies to assess the efficacy of probiotics in the treatment of cirrhosis and their effect on inflammatory factors, as well as to explore the relationship between gut microecological dysregulation and liver disease to gain a deeper understanding of this interaction. Up to December 2022, eligible studies were identified by searching the following databases: National Knowledge Infrastructure (CNKI), Wanfang Data, Web of Science, PubMed, Embase, Medline, and the Cochrane Library. Statistical analysis was performed using software RevMan Version 5.4. A total of 33 eligible randomized controlled trials were included in the study, and data on probiotic strains, duration of intervention, measures in the control group, and outcomes were extracted and evaluated. Compared to the control group, the experimental group had significant improvements in overall efficacy. The results of the meta-analysis revealed that probiotic use significantly decreased biochemical parameters for liver function, including aspartate transaminase, alanine aminotransferase, and total bilirubin. Similar result was obtained in interleukin-6, tumor necrosis factor-α, and endotoxin. However, probiotic intervention did not significantly affect interleukin-2 and interleukin-10. The current meta-analysis illustrates that probiotic supplementation reduces inflammatory markers and biochemical parameters for liver function in patients with cirrhosis, suggesting that probiotic management may be a novel treatment for cirrhosis. Furthermore, the interaction of the gut microbiota, associated metabolites, and inflammation factors with cirrhosis may provide a promising therapeutic target for the pharmacological and clinical treatment of cirrhosis.

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

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

Gut-liver axis in the progression of nonalcoholic fatty liver disease: From the microbial derivatives-centered perspective

Nonalcoholic fatty liver disease (NAFLD) is one of the world's most common chronic liver diseases. However, its pathogenesis remains unclear. With the deepening of research, NAFLD is considered a metabolic syndrome associated with the environment, heredity, and metabolic disorders. Recently, the close relationship between the intestinal microbiome and NAFLD has been discovered, and the theory of the "gut-liver axis" has been proposed. In short, the gut bacteria directly reach the liver via the portal vein through the damaged intestinal wall or indirectly participate in the development of NAFLD through signaling pathways mediated by their components and metabolites. This review focuses on the roles of microbiota-derived lipopolysaccharide, DNA, peptidoglycan, bile acids, short-chain fatty acids, endogenous ethanol, choline and its metabolites, indole and its derivatives, and bilirubin and its metabolites in the progression of NAFLD, which may provide significative insights into the pathogenesis, diagnosis, and treatment for this highly prevalent liver disease.

The microbiota and the gut-liver axis in primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) offers unique opportunities to explore the gut-liver axis owing to the close association between liver disease and colonic inflammation. It is well established that the gut microbiota in people with PSC differs from that of healthy individuals, but details of the microbial factors that demarcate PSC from inflammatory bowel disease (IBD) without PSC are poorly understood. In this Review, we aim to provide an overview of the latest literature on the gut microbiome in PSC and PSC with IBD, critically examining hypotheses on how microorganisms could contribute to the pathogenesis of PSC. A particular emphasis will be put on pathogenic features of the gut microbiota that might explain the occurrence of bile duct inflammation and liver disease in the context of IBD, and we postulate the potential existence of a specific yet unknown factor related to the gut-liver axis as causative in PSC. Available data are scrutinized in the perspective of therapeutic approaches related to the gut-liver axis.

Bile duct ligation differently regulates protein expressions of organic cation transporters in intestine, liver and kidney of rats through activation of farnesoid X receptor by cholate and bilirubin

Body is equipped with organic cation transporters (OCTs). These OCTs mediate drug transport and are also involved in some disease process. We aimed to investigate whether liver failure alters intestinal, hepatic and renal Oct expressions using bile duct ligation (BDL) rats. Pharmacokinetic analysis demonstrates that BDL decreases plasma metformin exposure, associated with decreased intestinal absorption and increased urinary excretion. Western blot shows that BDL significantly downregulates intestinal Oct2 and hepatic Oct1 but upregulates renal and hepatic Oct2. In vitro cell experiments show that chenodeoxycholic acid (CDCA), bilirubin and farnesoid X receptor (FXR) agonist GW4064 increase OCT2/Oct2 but decrease OCT1/Oct1, which are remarkably attenuated by glycine-β-muricholic acid and silencing FXR. Significantly lowered intestinal CDCA and increased plasma bilirubin levels contribute to different Octs regulation by BDL, which are confirmed using CDCA-treated and bilirubin-treated rats. A disease-based physiologically based pharmacokinetic model characterizing intestinal, hepatic and renal Octs was successfully developed to predict metformin pharmacokinetics in rats. In conclusion, BDL remarkably downregulates expressions of intestinal Oct2 and hepatic Oct1 protein while upregulates expressions of renal and hepatic Oct2 protein in rats, finally, decreasing plasma exposure and impairing hypoglycemic effects of metformin. BDL differently regulates Oct expressions via Fxr activation by CDCA and bilirubin.

Gut dysbiosis, endotoxemia and clotting activation: A dangerous trio for portal vein thrombosis in cirrhosis

Liver cirrhosis (LC) is associated with portal venous thrombosis (PVT) in roughly 20% of cirrhotic patients but the underlying mechanism is still unclear. Low-grade endotoxemia by lipopolysaccharides (LPS), a component of outer gut microbiota membrane, is detectable in the portal circulation of LC and could predispose to PVT. LPS may translocate into systemic circulation upon microbiota dysbiosis-induced gut barrier dysfunction, that is a prerequisite for enhanced gut permeability and ensuing endotoxemia. Experimental and clinical studies provided evidence that LPS behaves a pro-thrombotic molecule so promoting clotting and platelet activation. Experiments conducted in the portal circulation of cirrhotic patients showed the existence of LPS-related enhanced thrombin generation as well as endothelial dysfunction, venous stasis, and platelet activation. The review will analyze 1) the pro-thrombotic role of endotoxemia in the context of LC 2) the biological plausibility linking endotoxemia with PVT and 3) the potentially interventional tools to lower endotoxemia and eventually hypercoagulation.

Gut-derived low-grade endotoxaemia, atherothrombosis and cardiovascular disease

Systemic inflammation has been suggested to have a pivotal role in atherothrombosis, but the factors that trigger systemic inflammation have not been fully elucidated. Lipopolysaccharide (LPS) is a component of the membrane of Gram-negative bacteria present in the gut that can translocate into the systemic circulation, causing non-septic, low-grade endotoxaemia. Gut dysbiosis is a major determinant of low-grade endotoxaemia via dysfunction of the intestinal barrier scaffold, which is a prerequisite for LPS translocation into the systemic circulation. Experimental studies have demonstrated that LPS is present in atherosclerotic arteries but not in normal arteries. In atherosclerotic plaques, LPS promotes a pro-inflammatory status that can lead to plaque instability and thrombus formation. Low-grade endotoxaemia affects several cell types, including leukocytes, platelets and endothelial cells, leading to inflammation and clot formation. Low-grade endotoxaemia has been described in patients at risk of or with overt cardiovascular disease, in whom low-grade endotoxaemia was associated with atherosclerotic burden and its clinical sequelae. In this Review, we describe the mechanisms favouring the development of low-grade endotoxaemia, focusing on gut dysbiosis and changes in gut permeability; the plausible biological mechanisms linking low-grade endotoxaemia and atherothrombosis; the clinical studies suggesting that low-grade endotoxaemia is a risk factor for cardiovascular events; and the potential therapeutic tools to improve gut permeability and eventually eliminate low-grade endotoxaemia.

The Role of Rumen Microbiota and Its Metabolites in Subacute Ruminal Acidosis (SARA)-Induced Inflammatory Diseases of Ruminants

Subacute ruminal acidosis (SARA) is a common metabolic disease in ruminants. In the early stage of SARA, ruminants do not exhibit obvious clinical symptoms. However, SARA often leads to local inflammatory diseases such as laminitis, mastitis, endometritis and hepatitis. The mechanism by which SARA leads to inflammatory diseases is largely unknown. The gut microbiota is the totality of bacteria, viruses and fungi inhabiting the gastrointestinal tract. Studies have found that the gut microbiota is not only crucial to gastrointestinal health but also involved in a variety of disease processes, including metabolic diseases, autoimmune diseases, tumors and inflammatory diseases. Studies have shown that intestinal bacteria and their metabolites can migrate to extraintestinal distal organs, such as the lung, liver and brain, through endogenous pathways, leading to related diseases. Combined with the literature, we believe that the dysbiosis of the rumen microbiota, the destruction of the rumen barrier and the dysbiosis of liver function in the pathogenesis of SARA lead to the entry of rumen bacteria and/or metabolites into the body through blood or lymphatic circulation and place the body in the "chronic low-grade" inflammatory state. Meanwhile, rumen bacteria and/or their metabolites can also migrate to the mammary gland, uterus and other organs, leading to the occurrence of related inflammatory diseases. The aim of this review is to describe the mechanism by which SARA causes inflammatory diseases to obtain a more comprehensive and profound understanding of SARA and its related inflammatory diseases. Meanwhile, it is also of great significance for the joint prevention and control of diseases.

Circadian Rhythms Coordinated With Gut Microbiota Partially Account for Individual Differences in Hepatitis B-Related Cirrhosis

Cirrhosis is the end stage of chronic liver diseases like chronic hepatitis B. In China, hepatitis B accounts for around 60% of cases of cirrhosis. So far, clinical and laboratory indexes for the early diagnosis of cirrhosis are far from satisfactory. Nevertheless, there haven’t been specific drugs for cirrhosis. Thus, it is quite necessary to uncover more specific factors which play their roles in cirrhosis and figure out the possible therapeutic targets. Among emerging factors taking part in the initiation and progression of cirrhosis, gut microbiota might be a pivot of systemic factors like metabolism and immune and different organs like gut and liver. Discovery of detailed molecular mechanism in gut microbiota and gut liver axis leads to a more promising prospect of developing new drugs intervening in these pathways. Time-based medication regimen has been proofed to be helpful in hormonotherapy, especially in the use of glucocorticoid. Thus, circadian rhythms, though haven’t been strongly linked to hepatitis B and its complications, are still pivotal to various pathophysiological progresses. Gut microbiota as a potential effective factor of circadian rhythms has also received increasing attentions. Here, our work, restricting cirrhosis to the post-hepatitis B one, is aimed to summarize how circadian rhythms and hepatitis B-related cirrhosis can intersect via gut microbiota, and to throw new insights on the development of new and time-based therapies for hepatitis B-related cirrhosis and other cirrhosis.

Circulating microbiome in patients with portal hypertension

Portal hypertension (PH) in liver cirrhosis leads to increased gut permeability and the translocation of bacteria across the gut-liver axis. Microbial DNA has recently been detected in different blood compartments; however, this phenomenon has not been thoroughly analyzed in PH. This study aimed to explore circulating bacterial DNA signatures, inflammatory cytokines, and gut permeability markers in different blood compartments (peripheral and hepatic veins) of patients with cirrhosis and PH. The 16S rRNA blood microbiome profiles were determined in 58 patients with liver cirrhosis and 46 control patients. Taxonomic differences were analyzed in relation to PH, liver function, inflammatory cytokines, and gut permeability markers. Circulating plasma microbiome profiles in patients with cirrhosis were distinct from those of the controls and were characterized by enrichment of Comamonas, Cnuella, Dialister, Escherichia/Shigella, and Prevotella and the depletion of Bradyrhizobium, Curvibacter, Diaphorobacter, Pseudarcicella, and Pseudomonas. Comparison of peripheral and hepatic vein blood compartments of patients with cirrhosis did not reveal differentially abundant taxa. Enrichment of the genera Bacteroides, Escherichia/Shigella, and Prevotella was associated with severe PH (SPH) in both blood compartments; however, circulating microbiome profiles could not predict PH severity. Escherichia/Shigella and Prevotella abundance was correlated with IL-8 levels in the hepatic vein. In conclusion, we demonstrated a distinct circulating blood microbiome profile in patients with cirrhosis, showing that specific bacterial genera in blood are marginally associated with SPH, Model for End-Stage Liver Disease score, and inflammation biomarkers; however, circulating microbial composition failed to predict PH severity.

Resolvin D1 ameliorates hepatic steatosis by remodeling the gut microbiota and restoring the intestinal barrier integrity in DSS-induced chronic colitis

BACKGROUND AND PURPOSE

The maintenance of intestinalmucosalbarrier function plays an important role in hepatic steatosis. Increasing evidence has shown that resolvin D1 (RVD1) exerts a potential effect on hepatic steatosis. The aims of this study were to explore the mechanisms of RVD1 on hepatic steatosis based on the gut-liver axis and intestinal barrier function.

EXPERIMENTAL APPROACH

We established a DSS-induced chronic colitis model to evaluate hepatic steatosis. RVD1 was administered i.p. during the last 4 weeks. The colon and liver samples were stained with hematoxylin and eosin for histopathological analysis. The expression levels of intestinal tight junction genes and inflammatory genes were determined by quantitative PCR. The serum levels of glucose, cholesterol, triglycerides and LPS were measured, and the gut microbiota was analyzed by 16S rRNA gene sequencing.

KEY RESULTS

RVD1 prevented weight loss, histopathological changes, and elevated levels of inflammatory cytokines. Moreover, RVD1 administration attenuated DSS-induced hepatic steatosis and inflammatory responses in mice. In addition, RVD1 improved intestinal barrier function by increasing levels of tight junction molecules and decreasing the plasma LPS levels. The RVD1-treated mice also showed a different gut microbiota composition compared with found in the mice belonging to the DSS group but similar to that in normal chow diet-fed mice.

CONCLUSIONS AND IMPLICATIONS

RVD1 treatment ameliorates DSS-induced hepatic steatosis by ameliorating gut inflammation, improving intestinal barrier function and modulating intestinal dysbiosis.

Small intestinal bacterial overgrowth and orocecal transit time in patients of nonalcoholic fatty liver disease

OBJECTIVE

The aim of the present study is to explore the frequency of small intestinal bacterial overgrowth (SIBO) and orocecal transit time (OCTT) in patients with nonalcoholic fatty liver disease (NAFLD).

PATIENTS AND METHODS

103 patients with NAFLD and 49 healthy controls were enrolled. Clinical indicators such as BMI, liver function, blood lipids, homeostasis model assessment-insulin resistance (HOMA-IR), serum endotoxin of NAFLD patients were collected and examined. FibroTouch was used to detect the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM). SIBO and OCTT were measured by the lactulose hydrogen breath test.

RESULTS

The incidence of SIBO in NAFLD patients (58.3%) was significantly higher than that in healthy controls (26.5%). The level of serum endotoxin in NAFLD patients was higher than that in healthy controls. The levels of CAP, LSM, serum endotoxin, alanine transaminase, asperate aminotransferase and HOMA-IR in SBIO-positive NAFLD patients were higher than those in SIBO-negative patients. There was no significant difference in glutamyl transpeptidase triglyceride, low density lipoprotein and BMI between the two groups. OCTT in NAFLD patients was longer than that in healthy controls. It was also observed that OCTT in SIBO-positive NAFLD patients was significantly delayed compared with SIBO-negative NAFLD patients.

CONCLUSIONS

Patients with NAFLD exhibit the increased incidence rate of SIBO and prolonged OCTT; SIBO in NAFLD patients maybe a contributing factor to the elevated transaminase, hepatic steatosis, progression of liver fibrosis and prolonged OCTT.

Influence of Probiotics Administration Before Liver Resection in Patients with Liver Disease: A Randomized Controlled Trial

BACKGROUND

By inhibiting the growth of pathogenic bacteria and modulating the local intestinal immune system, probiotics may reduce bacterial translocation and systemic endotoxaemia, factors partially responsible for post-operative complications following liver resection for hepatocellular carcinoma in patients with cirrhosis.

METHODS

Patients with resectable hepatocellular carcinoma developed in the setting of chronic liver disease were prospectively divided into two equal-sized groups: one receiving probiotic treatment 14 days prior to surgery and the other receiving placebo. The primary endpoint was the level of circulating endotoxins after hepatectomy. Secondary endpoints were systemic inflammation (inflammatory cytokine levels), post-operative liver function and overall post-operative complication rate.

RESULTS

From May 2013 to December 2018, 64 patients were randomized, and 54 patients were included in the analysis, 27 in each arm. No significant change in endotoxin levels was observed over time in either group (P = 0.299). No difference between the groups in terms of post-operative liver function and overall complication rates was observed. The only differences observed were significant increases in the levels of TNFalpha (P = 0.019) and interleukin 1-b (P = 0.028) in the probiotic group in the post-operative period.

CONCLUSION

Contrary to the modest data reported in the literature, the administration of probiotics before minor liver resection for hepatocellular carcinoma developed in the setting of compensated chronic liver disease does not seem to have an impact on circulating endotoxin levels or post-operative complication rates.

TRIAL REGISTRATION

Trial registration: NCT02021253.

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.

Review of Rifaximin: A Summary of the Current Evidence and Benefits Beyond Licensed Use

Antibiotic resistance in patients with cirrhosis continues to draw significant attention. With a propensity to frequent hospitalisations, patients with cirrhosis are subject to frequent antibiotic prescription. This increases their risk of developing resistance to one or more antimicrobial agents, making management of their condition particularly challenging. Despite advancements being made in the management of liver disease, mortality rates continue to rise: almost 5-fold in those <65 years of age while remaining the leading cause of death in those 35–49 years of age. Alternative therapeutic options to prevent disease progression and cirrhosis-associated complications are urgently required; rifaximin is one such example. The medication use in patients with cirrhosis demonstrates additional benefits beyond current licensed use in the UK, that being for the prevention of hepatic encephalopathy and traveller’s diarrhoea; rifaximin has especially been explored beyond current licensed use in the context of enteric-driven pathologies. Through the therapy’s key central action as a broad-spectrum antimicrobial, rifaximin has the ability to modulate the gut–liver axis via removal of gut microbial products associated with the progression of cirrhosis and its sequalae. The benefits of rifaximin use continues to gather momentum, given its non-absorbable nature and well-tolerated side-effect profile, and these require consideration. With broad-spectrum antimicrobial properties, its use may assist in overcoming the conundrum posed of antibiotic resistance amongst patients with cirrhosis. This literature review discusses the chemical and antimicrobial properties of rifaximin, its licenced indication for use, and its reported benefits beyond this, as well as concerns regarding rifaximin resistance.

Compositional distinction of gut microbiota between Han Chinese and Tibetan populations with liver cirrhosis

BACKGROUND

Liver cirrhosis (LC) is caused by numerous chronic liver diseases and its complications are associated with qualitative and quantitative alterations of the gut microbiota. Previous studies have revealed the characteristics of gut microbiota in Han Chinese patients with LC and different compositions of gut microbiota were reported between the Tibetan and Han Chinese populations. This study was designed to evaluate the unique features of the gut microbiota of Tibetans and compare the differences of gut microbiota between Tibetan and Han Chinese patients with LC.

METHODS

Thirty-six patients with liver cirrhosis and nineteen healthy volunteers, from both Tibetan and Han Chinese populations, were enrolled and fecal samples were collected for 16S rRNA gene sequencing analyses.

RESULTS

Significant differences were found in the gut microbiota of healthy volunteers and between Tibetan and Han Chinese patients with LC. In the Han Chinese patients with cirrhosis (HLC) group the relative abundances of the phylum Bacteroidetes was significantly reduced (P < 0.001), whereas in the Tibetan patients with cirrhosis (TLC) group Firmicutes and Actinobacteria were highly enriched (P = 0.01 and 0.03, respectively). At the genus level, the relative abundances of Anaerostipes (P < 0.001), Bifidobacterium (P = 0.03), and Blautia (P = 0.004) were prevalent, while Alloprevotella, Dorea, Prevotella_2, Prevotella_7 and Prevotella_9 were decreased in the TLC group compared to the HLC group (P < 0.01).

CONCLUSION

Our findings showed how the intestinal bacterial community shifted in Tibetan patients with cirrhosis.

Leaky Gut and Gut-Liver Axis in Liver Cirrhosis: Clinical Studies Update

Portal blood flows into the liver containing the gut microbiome and its products such as endotoxin and bacterial DNA. The cirrhotic liver acts and detoxifies as the initial site of microbial products. In so-called "leaky gut," the increased intestinal permeability for bacteria and their products constitutes an important pathogenetic factor for major complications in patients with liver cirrhosis. Prolonged gastric and small intestinal transit may induce intestinal bacterial overgrowth, a condition in which colonic bacteria translocate into the small gut. Cirrhotic patients further show gut dysbiosis characterized by an overgrowth of potentially pathogenic bacteria and a decrease in autochthonous nonpathogenic bacteria. Pathological bacterial translocation (BT) is a contributing factor in the development of various severe complications. Bile acids (BAs) undergo extensive enterohepatic circulation and play important roles in the gut-liver axis. BT-induced inflammation prevents synthesis of BAs in the liver through inhibition of BA-synthesizing enzyme CYP7A1. A lower abundance of 7α-dehydroxylating gut bacteria leads to decreased conversion of primary to secondary BAs. Decreases in total and secondary BAs may play an important role in the gut dysbiosis characterized by a proinflammatory and toxic gut microbiome inducing BT and endotoxemia, as addressed in my previous reviews. Selective intestinal decontamination by the use of various antimicrobial drugs for management of complications has a long history. Lactobacillus GG decreasing endotoxemia is reported to improve the microbiome with beneficial changes in amino acid, vitamin and secondary BA metabolism. Current approaches for hepatic encephalopathy are the use of nonabsorbable antibiotics and disaccharides. Probiotics may become an additional therapeutic option for advanced liver cirrhosis.

Roles and mechanisms of circulating CEACAM1 in the cirrhosis-related intestinal hyperpermeability: in vitro approach

BACKGROUND

Cirrhosis-related intestinal hyperpermeability and endotoxemia are characterized by intestinal epithelial cell apoptosis, impaired restitution (proliferation and migration), decreased tight junction protein levels, and subsequent barrier dysfunction. In addition to endotoxin and tumor necrosis factor-α (TNFα), carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) plays crucial roles in the regulation of apoptosis, restitution, tight junction protein-maintained barrier function of intestinal epithelial cells.

METHODS

This study aims to explore the roles and underlying mechanisms of CEACAM1 in cirrhosis-related intestinal hyperpermeability through in vitro approach.

RESULTS

In cirrhotic patients, high serum levels of intestinal hyperpermeability (zonulin and endotoxin) markers were accompanied by elevated serum levels of TNFα and soluble CEACAM1. In in vitro experiments, we evaluated the individual and interacted roles of TNFα and human recombinant CEACAM1 (hrCEACAM1) in LC-sera (sera of cirrhotic patients)-induced intestinal hyperpermeability-related pathogenic signals. In the cell Line human from human colon (Caucasian colon adenocarcinoma) (Caco-2) cell culture, LC-sera, TNFα, and hrCEACAM1 increased apoptosis (measured by Terminal deoxynucleotidyl transferase [TdT] dUTP nick end labeling+/annexin-5+propidium iodide+ cells and caspase-3 activity), decreased restitution capacity (proliferation and migration), and disrupted tight junction protein-maintained barrier function in Caco-2 cells. The pathogenic changes mentioned above were accompanied by an increase in intracellular reactive oxygen species (ROS) levels, lactate dehydrogenase release, and endoplasmic reticulum stress-related signals in the LC-sera or TNFα-pretreated Caco-2 cells. Concomitant incubation of Caco-2 cells with anti-CEACAM1 suppressed these LC-sera or TNFα-induced negative effects on restitution, barrier function, and cell viability.

CONCLUSION

This study demonstrated that sera from cirrhotic patients contain soluble CEACAM1, which is involved in the pathogenesis of intestinal hyperpermeability. Accordingly, it is noteworthy to explore the potential use of anti-CEACAM1 treatment for cirrhosis-related intestinal hyperpermeability and endotoxemia.

Therapeutic Applications of Resveratrol in Hepatic Encephalopathy through Its Regulation of the Microbiota, Brain Edema, and Inflammation

Hepatic encephalopathy is a common complication in patients with liver cirrhosis and portosystemic shunting. Patients with hepatic encephalopathy present a variety of clinical features, including neuropsychiatric manifestations, cognitive dysfunction, impaired gut barrier function, hyperammonemia, and chronic neuroinflammation. These pathogeneses have been linked to various factors, including ammonia-induced oxidative stress, neuronal cell death, alterations in the gut microbiome, astrocyte swelling, and blood-brain barrier disruptions. Many researchers have focused on identifying novel therapeutics and prebiotics in the hope of improving the treatment of these conditions. Resveratrol is a natural polyphenic compound and is known to exert several pharmacological effects, including antioxidant, anti-inflammatory, and neuroprotective activities. Recent studies suggest that resveratrol contributes to improving the neuropathogenic effects of liver failure. Here, we review the current evidence describing resveratrol's effects in neuropathogenesis and its impact on the gut-liver axis relating to hepatic encephalopathy. We highlight the hypothesis that resveratrol exerts diverse effects in hepatic encephalopathy and suggest that these effects are likely mediated by changes to the gut microbiota, brain edema, and neuroinflammation.

Liver cirrosis and complication risk management

Liver cirrhosis (LC) takes the main place in the structure of the pathology of the digestive system in terms of the frequency of mortality, as well as in the development of fatal and poorly controlled complications, which requires the search for effective methods for preventing the progression of the disease and the development of complications. The article provides updated information on the role of the intestinal microbiota, as well as endotoxemia and increased intestinal permeability syndromes in the pathophysiology of LC and its complications. The results of recent meta-analyses of the impact of dysbiotic disorders on the prognosis of the LC and the options for their correction are presented. Understanding of the significance of involvement of gut microbiota in the pathogenesis of LC has become one of the levers of management of the risks of complications of LC. In this case, the livergut axis can be considered to be the leading link to the formation of most of the main complications of LC.

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

AIM

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

METHODS

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

FINDINGS

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

SIGNIFICANCE

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

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.

Diet-Regulating Microbiota and Host Immune System in Liver Disease

The gut microbiota has been known to modulate the immune responses in chronic liver diseases. Recent evidence suggests that effects of dietary foods on health care and human diseases are related to both the immune reaction and the microbiome. The gut-microbiome and intestinal immune system play a central role in the control of bacterial translocation-induced liver disease. Dysbiosis, small intestinal bacterial overgrowth, translocation, endotoxemia, and the direct effects of metabolites are the main events in the gut-liver axis, and immune responses act on every pathways of chronic liver disease. Microbiome-derived metabolites or bacteria themselves regulate immune cell functions such as recognition or activation of receptors, the control of gene expression by epigenetic change, activation of immune cells, and the integration of cellular metabolism. Here, we reviewed recent reports about the immunologic role of gut microbiotas in liver disease, highlighting the role of diet in chronic liver disease.

Gut dysbiosis is associated with poorer long-term prognosis in cirrhosis

BACKGROUND

Gut dysbiosis is common in cirrhosis.

AIM

To study the influence of gut dysbiosis on prognosis in cirrhosis.

METHODS

The case-control study included 48 in-patients with cirrhosis and 21 healthy controls. Stool microbiome was assessed using 16S ribosomal ribonucleic acid gene sequencing. We used modified dysbiosis ratio (MDR): [Bacilli (%) + Proteobacteria (%)]/[Clostridia (%) + Bacteroidetes (%)]. Patients with MDR more the median made up the group with severe dysbiosis, others did the group with non-severe dysbiosis. The follow-up period was 4 years.

RESULTS

The mortality rate of patients with severe dysbiosis was significantly higher than that of patients with non-severe dysbiosis (54.2% vs 12.5%; P = 0.001). The presence of severe dysbiosis was independent risk factors for death [hazard ratio = 8.6 × (1.9-38.0); P = 0.005]. The abundance of Enterobacteriaceae (P = 0.002), Proteobacteria (P = 0.002), and Lactobacillaceae (P = 0.025) was increased and the abundance of Firmicutes (P = 0.025) and Clostridia (P = 0.045) was decreased in the deceased patients compared with the survivors. The deceased patients had a higher MDR value than the survivors [0.131 × (0.069-0.234) vs 0.034 × (0.009-0.096); P = 0.004]. If we applied an MDR value of 0.14 as the cutoff point, then it predicted patient death within the next year with a sensitivity of 71.4% and a specificity of 82.9% [area under the curve = 0.767 × (0.559-0.974)]. MDR was higher in patients with cirrhosis than in health controls [0.064 × (0.017-0.131) vs 0.005 × (0.002-0.007); P < 0.001], and in patients with decompensated cirrhosis than in patients with compensated cirrhosis [0.106 × (0.023-0.211) vs 0.033 × (0.012-0.074); P = 0.031]. MDR correlated negatively with prothrombin (r = -0.295; P = 0.042), cholinesterase (r = -0.466; P = 0.014) and serum albumin (r = -0.449; P = 0.001) level and positively with Child–Turcotte–Pugh scale value (r = 0.360; P = 0.012).

CONCLUSION

Gut dysbiosis is associated with a poorer long-term prognosis in cirrhosis.

Non-Selective Beta-Blockers Decrease Infection, Acute Kidney Injury Episodes, and Ameliorate Sarcopenic Changes in Patients with Cirrhosis: A Propensity-Score Matching Tertiary-Center Cohort Study

Background: Cirrhotic complications resulting from portal hypertension can be considerably reduced by non-selective beta-blockers (NSBBs); however, scarce studies have investigated therapeutic agents for other complications. We aimed to investigate the effects of NSBBs on common cirrhotic complications of infection, acute kidney injury (AKI), chronic renal function declination, and sarcopenic changes. Methods: Medical records of hospitalization for cirrhosis with at least a 4-year follow-up were analyzed and selected using propensity-score matching (PSM). Generalized estimating equation (GEE) was applied to assess the association of NSBBs with infection requiring hospitalization and AKI. Chronic renal function declination was evaluated by slope of regression lines derived from reciprocal of the serum creatinine level. The covariates of CT-measured skeletal muscle index (SMI) alterations were analyzed by generalized linear mixed model. Results: Among the 4946 reviewed individuals, 166 (83 NSBB group, 83 non-NSBB group) were eligible. Using GEE, Charlson comorbidity index, Child-Pugh score and non-NSBB were risk factors for infection; non-NSBB group revealed a robust trend toward AKI, showed no significant difference with chronic renal function declination of NSBB group, and was negatively associated with SMI alteration. Conclusion: Chronic NSBB use lowered the episodes of infection requiring hospitalization and AKIs, whereas non-NSBB was associated with sarcopenic changes.

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.

The effect of malnutrition on the infectious outcomes of hospitalized patients with cirrhosis: analysis of the 2011-2017 hospital data

BACKGROUND

In patients with cirrhosis, there is a clinical concern that the development of protein-calorie malnutrition will affect the immune system and predispose these patients to increased infectious outcomes.

AIMS

In this study, we evaluate the effects of malnutrition on the infectious outcomes of patients admitted with cirrhosis.

MATERIALS AND METHODS

This study used the 2011-2017 National Inpatient Sample to identify patients with cirrhosis. These patients were stratified using malnutrition (protein-calorie malnutrition, cachexia, and sarcopenia) and matched using age, gender, and race with 1:1 nearest neighbor matching method. The endpoints included mortality and infectious outcomes.

RESULTS

After matching, there were 96 842 malnutrition-present cohort and equal number of controls. In univariate analysis, the malnutrition cohort had higher hospital mortality [10.40 vs. 5.04% P < 0.01, odds ratio (OR) 2.18, 95% confidence interval (CI) 2.11-2.26]. In multivariate models, malnutrition was associated with increased mortality [P < 0.01, adjusted odds ratio (aOR) 1.32, 95% CI 1.27-1.37] and infectious outcomes, including sepsis (P < 0.01, aOR 1.94, 95% CI 1.89-2.00), pneumonia (P < 0.01, aOR 1.68, 95% CI 1.63-1.73), UTI (P < 0.01, aOR 1.39, 95% CI 1.35-1.43), cellulitis (P < 0.01, aOR 1.09, 95% CI 1.05-1.13), cholangitis (P < 0.01, aOR 1.39, 95% CI 1.26-1.55), and clostridium difficile (P < 0.01, aOR 2.11, 95% CI 1.92-2.31).

CONCLUSION

The results of this study indicate that malnutrition is an independent risk factor of hospital mortality and local/systemic infections in patients admitted with cirrhosis.

Early Administration of Tolvaptan Can Improve Survival in Patients with Cirrhotic Ascites

(1) Backgrounds and aim: Tolvaptan, a selective vasopressin type 2 receptor antagonist, was approved for ascites, and its short-term efficacy and safety have been confirmed. However, it is still unclear whether this novel drug may improve long-term survival rates in cirrhotic patients with ascites. (2) Patients and methods: A total of 206 patients who responded insufficiently to conventional diuretics and were hospitalized for refractory ascites for the first time were retrospectively enrolled in this study. Among them, the first 57 consecutive patients were treated with conventional diuretics (the conventional therapy group); the latter 149 consecutive patients were treated with tolvaptan in addition to the conventional therapy (the tolvaptan group). (3) Results: The exacerbation of renal function was significantly milder in the tolvaptan group than in the conventional therapy group. The prognostic factors for survival in the tolvaptan group were being male, having hyperbilirubinemia, having a high blood urea nitrogen (BUN), and receiving high-dose furosemide at the start of tolvaptan treatment. The one-year and three-year cumulative survival rates were 67.8 and 45.3%, respectively, in patients with low-dose furosemide (<40 mg/day) at the start of tolvaptan treatment. The prognosis was significantly better in the tolvaptan group with low-dose furosemide than in the conventional therapy group (p < 0.001). (4) Conclusion: Tolvaptan can improve survival in patients with cirrhotic ascites, especially when tolvaptan is started before high-dose furosemide administration.

Continuous elevation of procalcitonin in cirrhosis combined with hepatic carcinoma: a case report

BACKGROUND

Serum levels of procalcitonin (PCT) are considered a useful biomarker for the diagnosis of bacterial infection or inflammation. There are few reports of high PCT levels in end-stage liver disease regardless of bacterial infection. Here, we present a case of extremely high PCT levels (> 100 ng/mL) in a patient with severe cirrhosis combined with hepatic carcinoma.

CASE PRESENTATION

A 65-year-old man developed end-stage cirrhosis with hepatic carcinoma. Radiographic imaging showed a massive hepatocellular carcinoma with multiple loci lack of indications of resection. Hence, transcatheter hepatic arterial chemoembolization was performed three times over a period of 4 months. Before and after interventional therapies, the biochemistry laboratory results were only slightly abnormal except for persistently high PCT concentrations (> 100 ng/mL), irrespective of the evidence for bacterial infection or sepsis.

CONCLUSIONS

This case suggests that continuously high levels of PCT (> 100 ng/mL) may be present in advanced liver disease, particularly in complex situations such as decompensated cirrhosis and liver cancer, in the absence of severe infection or sepsis. This knowledge could expand the significance of PCT in liver disease.

Gut microbiome changes in Nonalcoholic fatty liver disease & alcoholic liver disease

Nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are some of the most common liver diseases worldwide. The human gut microbiome is dynamic and shifts in bacterial composition have been implicated in many diseases. Studies have shown that there is a shift in bacterial overgrowth favoring pro-inflammatory mediators in patients with advanced disease progression such as cirrhosis. Further investigation demonstrated that the transplantation of gut microbiota from advanced liver disease patients can reproduce severe liver inflammation and injury in mice. Various techniques in manipulating the gut microbiota have been attempted including fecal transplantation and probiotics. This review focuses on the changes in the gut microbiota as well as emerging lines of microbiome work with respect to NAFLD and ALD.

Polymyxin B engineered polystyrene-divinylbenzene microspheres for the adsorption of bilirubin and endotoxin

Hemoperfusion is an important strategy for liver disease treatment. Polystyrene-divinylbenzene (PS-DVB) microspheres are widely applied as absorbents in hemoperfusion to efficiently remove the important toxin bilirubin. However, as another common toxin, endotoxin will remain during this process and cause endotoxemia. Therefore, simultaneous removal of both bilirubin and endotoxin is highly desirable. In the present study, we engineered PS-DVB microspheres with polymyxin B sulfate (PMB) to meet this goal. After modification, the novel PMB-engineered (P-PMB) microspheres displayed excellent biocompatibility and hemocompatibility. Notably, compared to PS-DVB microspheres, P-PMB microspheres exhibited markedly stronger detoxification of both bilirubin and endotoxin, increasing by 17.03% and 42.57%, respectively. Overall, we believe that the novel P-PMB microspheres have considerable potential for liver disease treatment in clinical practice.

A new adsorbent for hemoperfusion was successfully prepared by grafting polymyxin B (PMB) on the surface of polystyrene divinylbenzene (PS-DVB) microspheres. It showed good biocompatibility and could adsorb both bilirubin and endotoxin.