Decompensated liver cirrhosis (dLC) is associated with intestinal dysbiosis, however, underlying reasons and clinical consequences remain largely unexplored. We investigated bacterial and fungal microbiota, their relation with gut barrier integrity, inflammation, and cirrhosis-specific complications in dLC-patients. Competing-risk analyses were performed to investigate clinical outcomes within 90 days. Samples were prospectively collected from 95 dLC-patients between 2017 and 2022. Quantitative metagenomic analyses clustered patients into three groups (G1-G3) showing distinct microbial patterns. G1 (n = 39) displayed lowest diversity and highest Enterococcus abundance, G2 (n = 24) was dominated by Bifidobacteria, G3 (n = 29) was most diverse and clustered most closely with healthy controls (HC). Of note, bacterial concentrations were significantly lower in cirrhosis compared with HC, especially for G1 that also showed the lowest capacity to produce short chain fatty acids and secondary bile acids. Consequently, fungal overgrowth, dominated by Candida spp. (51.63%), was observed in G1. Moreover, G1-patients most frequently received antibiotics (n = 33; 86.8%), had highest plasma-levels of Zonulin (p = 0.044) and a proinflammatory cytokine profile along with numerically higher incidences of subsequent infections (p = 0.09). In conclusion, distinct bacterial clusters were observed at qualitative and quantitative levels and correlated with fungal abundances. Antibiotic treatment significantly contributed to dysbiosis, which translated into intestinal barrier impairment and systemic inflammation.

Hepatopulmonary syndrome (HPS) is a pulmonary vascular complication of liver disease and/or portal hypertension. HPS manifests as impaired gas exchange and hypoxemia due to intrapulmonary vascular dilatations and shunts. In response to primary liver disease, the abnormal adaptation of respiratory epithelial cells, pulmonary endothelial cells and immune cells leads to pulmonary microenvironment disequilibrium and HPS. In this review, we explore the pathophysiologic mechanisms of HPS, including vascular dilation, angiogenesis and alveolar dysfunction. The liver is the primary contributor to HPS, and liver transplantation is the only treatment that generally reverses HPS. We then discuss how disruption of hepatic sinusoidal homeostasis may impact the progression of HPS, mainly focusing on hepatocytes, cholangiocytes, LSECs and macrophages. As HPS occurs more commonly in advanced liver cirrhosis, we also discuss that normalisation of liver dysfunction and portal hypertension is crucial for the resolution of HPS. In conclusion, liver-targeted therapies may be effective in treating HPS.

This article provides an overview of the advancements in the application of fecal microbiota transplantation (FMT) in treating diseases related to intestinal dysbiosis. FMT involves the transfer of healthy donor fecal microbiota into the patient's body, aiming to restore the balance of intestinal microbiota and thereby treat a variety of intestinal diseases such as recurrent Clostridioides difficile infection (rCDI), inflammatory bowel disease (IBD), constipation, short bowel syndrome (SBS), and irritable bowel syndrome (IBS). While FMT has shown high efficacy in the treatment of rCDI, further research is needed for its application in other chronic conditions. This article elaborates on the application of FMT in intestinal diseases and the mechanisms of intestinal dysbiosis, as well as discusses key factors influencing the effectiveness of FMT, including donor selection, recipient characteristics, treatment protocols, and methods for assessing microbiota. Additionally, it emphasizes the key to successful FMT. Future research should focus on optimizing the FMT process to ensure long-term safety and explore the potential application of FMT in a broader range of medical conditions.

Cirrhosis complications are often triggered by bacterial infections with multidrug-resistant organisms. Alterations in the gut and oral microbiome in decompensated cirrhosis (DC) influence clinical outcomes. We interrogated: (i) gut and oral microbiome community structures, (ii) virulence factors (VFs) and antimicrobial resistance genes (ARGs) and (iii) oral-gut microbial overlap in patients with differing cirrhosis severity.

Fifteen healthy controls (HCs), as well as 26 patients with stable cirrhosis (SC), 46 with DC, 14 with acute-on-chronic liver failure (ACLF) and 14 with severe infection without cirrhosis participated. Metagenomic sequencing was undertaken on paired saliva and faecal samples. 'Salivatypes' and 'enterotypes' based on genera clustering were assessed against cirrhosis severity and clinical parameters. VFs and ARGs were evaluated in oral and gut niches, and distinct resistotypes identified.

Salivatypes and enterotypes revealed a greater proportion of pathobionts with concomitant reduction in autochthonous genera with increasing cirrhosis severity and hyperammonaemia. Increasing overlap between oral and gut microbiome communities was observed in DC and ACLF vs. SC and HCs, independent of antimicrobial, beta-blocker and gastric acid-suppressing therapies. Two distinct gut microbiome clusters harboured genes encoding for the PTS (phosphoenolpyruvate:sugar phosphotransferase system) and other VFs in DC and ACLF. Substantial ARGs (oral: 1,218 and gut: 672) were detected (575 common to both sites). The cirrhosis resistome was distinct, with three oral and four gut resistotypes identified, respectively.

The degree of oral-gut microbial community overlap, frequency of VFs and ARGs all increase significantly with cirrhosis severity, with progressive dominance of pathobionts and loss of commensals. Despite similar antimicrobial exposure, patients with DC and ACLF have reduced microbial richness compared to patients with severe infection without cirrhosis, supporting the additive pathobiological effect of cirrhosis.

This research underscores the crucial role of microbiome alterations in the progression of cirrhosis in an era of escalating multidrug resistant infections, highlighting the association and potential impact of increased oral-gut microbial overlap, virulence factors, and antimicrobial resistance genes on clinical outcomes. These findings are particularly significant for patients with decompensated cirrhosis and acute-on-chronic liver failure, as they reveal the intricate relationship between microbiome alterations and cirrhosis complications. This is relevant in the context of multidrug-resistant organisms and reduced oral-gut microbial diversity that exacerbate cirrhosis severity, drive hepatic decompensation and complicate treatment. For practical applications, these insights could guide the development of targeted microbiome-based therapeutics and personalised antimicrobial regimens for patients with cirrhosis to mitigate infectious complications and improve clinical outcomes.

This review highlights the causes, types and clinical staging of hepatic encephalopathy (HE). Current concepts on the probable pathogenetic mechanisms and currently practiced therapeutic options are discussed.

HE may be covert and overt. Also known as minimal HE. Covert HE, where there are behavioral abnormalities and impairment in activities of daily living with intact sensorium. The pathophysiology of HE remains poorly understood. There is disturbance of the urea cycle due to liver disease leading to increased production of ammonia. The ammonium ion enters the astrocytes along with glutamate (converted to glutamine by ammonia) and myo-inositol, thereby increasing the osmolality of the astrocytic cytoplasm. This osmotic gradient results in accumulation of water inside the astrocytes resulting in cerebral edema and increase in brain volume. Additionally, current research has noted the role of cerebral oxidative/nitrosative stress and the synergistic effects of increased cerebral ammonia and alteration in neurotransmitters, neurometabolites, and cortical excitability due to systemic inflammation. In advanced liver disease with systemic infection or inflammation, neuroinflammatory processes play significant role in the development of HE. Inflammatory cytokines like TNF-α, IL-6, IL-17 in presence of hyperammonemia have been found to induce neurotoxicity of ammonia by passing through the blood brain barrier and causing enlarged/swollen pale astrocytes, resulting in HE. Disrupted enterohepatic circulation in end stage liver disease also causes elevation of bile acids which induces neuroinflammation. Manganese and zinc play as co-factors of enzymatic reaction. These metal deposition causes multiple psychomotor symptoms observed in HE. The gut environment has a major impact on brain function in patients with HE. Toxins such as ammonia and inflammatory cytokines produced by this impaired intestinal flora access the circulation through porto-systemic anastomoses and exacerbate or precipitate HE. Finally, as a result of recurrent cerebral edema from astrocytic dysfunction and neuroinflammation, permanent neurodegeneration occurs with cognitive decline and motor disturbances, especially parkinsonian features and gait disturbances. This is the stage of chronic hepatic encephalopathy. Currently L-ornithine L-aspartate (LOLA) is being used to lower the ammonia level by stimulating the urea cycle. HE comprises a broad spectrum of neurological and/or psychiatric abnormalities caused by hepatic insufficiency and/or portal-systemic shunting in the absence of any other causes of brain dysfunction. HE may be caused or precipitated by several factors like infections, intoxications and drugs. The encephalopathic features may be covert or overt. The pathogenetic mechanisms for HE may be different. In the presence of liver disease, HE primarily results from disturbed urea cycle with hyperammonemia causing astrocytic swelling and cerebral edema. Porto-systemic anastomoses with intact liver function can cause HE by allowing ammonia and other toxins produced by the gut microbial flora and allowing these to bypass detoxification by the liver and exposing the brain to their harmful effects. Principles of therapy are twofold. First protecting the liver and the brain from gut generated ammonia and other toxins by ensuring smooth bowel function and avoiding stagnation with the use of osmotic laxatives like lactulose or lactitol and also reducing the gut microbial load with use of anti-bacterials/bacteriophages like neomycin and rifaximin along with metronidazole. Second, reducing the already generated cerebral edema by use of mannitol and appropriate ventilatory support. Currently L-ornithine L-aspartate (LOLA) is being used to reduce the ammonia load to the liver. LOLA is a stable compound formed from two amino acids. L-ornithine plays a crucial role in stimulating the urea cycle, leading to a reduction in ammonia levels. Both L-ornithine and L-aspartate serve as substrates for the enzyme glutamate transaminase, and their administration results in elevated glutamate concentrations. Ammonia is subsequently utilized in the conversion of glutamate to glutamine through the action of glutamine synthetase. Finally in resistant cases the use of liver transplant needs to be considered. Alternatively extracorporeal liver assist devices may be used like Molecular Adsorbent Recirculating System (MARS) or Single-Pass Albumin Dialysis (SPAD).

Alcohol misuse is associated with disruption of the microbial homeostasis (dysbiosis) and microbial overgrowth in the gut, gut barrier disruption, and translocation of microbes into the systemic circulation. It also induces changes in regulatory mechanisms of the gut, which is the largest peripheral immune organ. The gut-liver axis is important for health and disease, and alterations in the intestinal immune system contribute to alcohol-associated liver disease (ALD). Understanding these changes might help discover new targets for drugs and therapeutic approaches.

A systematic literature search was conducted in PubMed, Medline, and Embase of manuscripts published between January 2000 and November 2023 using the terms ("alcohol" or "ethanol") AND ("immune" or "immunol") AND ("intestine," "colon," or "gut"). Eligible manuscripts included studies and reviews that discussed the effects of ethanol on immune cells in the intestine.

A total of 506 publications were found in the databases on November 20, 2023. After excluding duplicates and research not covering ALD (415 articles), 91 studies were reviewed. Also included were manuscripts covering specific immune cells in the context of ALD.

Balancing immune tolerance vs. initiating an immune response challenges the intestinal immune system. Alcohol induces disruption of the intestinal barrier, which is accompanied by a thicker mucus layer and reduced anti-microbial peptides. This leads to longer attachment of bacteria to epithelial cells and consequently greater translocation into the circulation. Bacterial translocation activates the immune system, reducing the activity of regulatory T cells and inducing T helper 17 response via a variety of pathways. The role of innate immune cells, especially Type 3 innate lymphoid cells, and of specific B- and T-cell subsets in ALD remains elusive. Gut dysbiosis, translocation of viable bacteria and bacterial products into the circulation, and changes in the intestinal barrier have been linked to immune deficiency and infections in patients with cirrhosis. Modifying the intestinal immune system could reduce intestinal inflammation and alcohol-induced liver injury. Understanding the underlying pathophysiology can help to detect new targets for drugs and design therapeutic strategies.

There are no useful treatments to prevent the development of severe complications of liver cirrhosis. Simvastatin and rifaximin have shown beneficial effects in liver cirrhosis.

To assess whether simvastatin combined with rifaximin improves outcomes in patients with decompensated cirrhosis.

Double-blind, placebo-controlled, phase 3 trial conducted among patients with decompensated cirrhosis in 14 European hospitals between January 2019 and December 2022. The last date of follow-up was December 2022.

Patients were randomly assigned to receive simvastatin, 20 mg/d, plus rifaximin, 1200 mg/d (n = 117), or identical-appearing placebo (n = 120) for 12 months in addition to standard therapy, stratified according to Child-Pugh class B or C.

The primary end point was incidence of severe complications of liver cirrhosis associated with organ failure meeting criteria for acute-on-chronic liver failure. Secondary outcomes included transplant or death and a composite end point of complications of cirrhosis (ascites, hepatic encephalopathy, variceal bleeding, acute kidney injury, and infection).

Among the 237 participants randomized (Child-Pugh class B: n = 194; Child-Pugh class C: n = 43), 72% were male and the mean age was 57 years. There were no differences between the 2 groups in terms of development of acute-on-chronic liver failure (21 [17.9%] vs 17 [14.2%] patients in the treatment and placebo groups, respectively; hazard ratio, 1.23; 95% CI, 0.65-2.34; P = .52); transplant or death (22 [18.8%] vs 29 [24.2%] patients in the treatment and placebo groups, respectively; hazard ratio, 0.75; 95% CI, 0.43-1.32; P = .32); or development of complications of cirrhosis (50 [42.7%] vs 55 [45.8%] patients in the treatment and placebo groups, respectively; hazard ratio, 0.93; 95% CI, 0.63-1.36; P = .70). Incidence of adverse events was similar in both groups (426 vs 419; P = .59), but 3 patients in the treatment group (2.6%) developed rhabdomyolysis.

The addition of simvastatin plus rifaximin to standard therapy does not improve outcomes in patients with decompensated liver cirrhosis.

ClinicalTrials.gov Identifier: NCT03780673.

Hepatic encephalopathy (HE) is a debilitating neurological condition associated with cirrhosis, characterized by cognitive impairment ranging from minimal to overt symptoms. It significantly impacts patients' quality of life and substantially burdens healthcare systems. This review examines current prophylactic strategies for HE, focusing on established treatments, emerging therapies, and predictive tools to identify high-risk patients. Traditional treatments such as lactulose and rifaximin remain the cornerstone of HE management, effectively reducing ammonia levels and preventing recurrence. However, novel approaches like L-ornithine L-aspartate, albumin infusions, and antioxidants like resveratrol show promise in further improving outcomes by addressing underlying pathophysiological mechanisms, including systemic inflammation and gut dysbiosis. Developing predictive models, such as the AMMON-OHE score and clinical-genetic risk assessments, enhances the ability to tailor preventive interventions to individual patient profiles. These advancements are crucial in mitigating the incidence of overt HE, reducing hospital admissions, and improving patient survival rates. The future of HE management lies in personalized medicine, targeting specific inflammatory and metabolic pathways, with the potential integration of genetic manipulation. Continued research is essential to refine these strategies, ultimately aiming to improve the prognosis and quality of life for cirrhotic patients at risk of HE.

Acute-on-chronic liver failure (ACLF) is a severe condition in patients with decompensated liver cirrhosis, marked by high short-term mortality. Recent experimental and clinical evidence has linked intestinal dysfunction to both the initiation of ACLF as well as disease outcome. This review discusses the significant role of the gut-liver axis in ACLF pathogenesis, highlighting recent advances. Gut mucosal barrier disruption, gut dysbiosis, and bacterial translocation emerge as key factors contributing to systemic inflammation in ACLF. Different approaches of therapeutically targeting the gut-liver axis via farnesoid X receptor agonists, nonselective beta receptor blockers, antibiotics, and probiotics are discussed as potential strategies mitigating ACLF progression. The importance of understanding the distinct pathophysiology of ACLF compared with other stages of liver cirrhosis is highlighted. In conclusion, research findings suggest that disruption of intestinal integrity may be an integral component of ACLF pathogenesis, paving the way for novel diagnostic and therapeutic approaches to manage this syndrome more effectively.

Introduction. The study of gut microbiota is now an essential dimension in many clinical studies. For instance, microbiota diversity investigation can help us to better manage cirrhotic patients by the identification of markers of severity and the identification of possible sources of pathogens.Hypothesis/Gap Statement. Conducting clinical research on gut microbiota for fragile patients in intensive care units, such as cirrhotic patients, poses significant challenges.Aim. In this study, we developed a comprehensive toolkit for investigating gut microbiota in fragile patients using rectal swabbing combined with straightforward lifestyle and clinical questionnaires.Methodology . We applied this prospective approach to 49 well-phenotyped cirrhotic patients as a function of their compensation status (compensated patients with outpatients' recruitment vs decompensated patients in intensive care units).Results . Our results, consistent with the literature, showed that liver function impairment is associated with lower microbiota diversity. Additionally, we monitored aerobic microbiota in decompensated cirrhotic patients, observing the invasion of extended spectrum beta-lactamase (ESBL)-producing Escherichia coli in the gut's aerobic microbiota prior to severe infection caused by these pathogens.Conclusion. We propose this pragmatic methodology for larger cohort studies, aiming to enhance the monitoring of immunocompromised patients by using microbiota analysis as a predictive tool for the severity of associated pathologies and the identification of agents responsible for severe infections.

Acute-on-chronic liver failure (ACLF) is a critical syndrome that develops in patients with chronic liver disease and is characterized by acute decompensation, single- or multiple-organ failure and high short-term mortality. Over the past few decades, ACLF has been progressively recognized as an independent clinical entity, and several criteria and prognostic scores have been proposed and validated by different scientific societies. However, controversies still exist in some aspects across regions, which mainly involve whether the definition of underlying liver diseases should include cirrhosis and non-cirrhosis. The pathophysiology of ACLF is complicated and remains unclear, although accumulating evidence based on different aetiologies of ACLF shows that it is closely associated with intense systemic inflammation and immune-metabolism disorder, which result in mitochondrial dysfunction and microenvironment imbalance, leading to disease development and organ failure. In-depth insight into the biological pathways involved in the mechanisms of ACLF and potential mechanistic targets that improve patient survival still needs to be investigated. Omics-based analytical techniques, including genomics, transcriptomics, proteomics, metabolomics and microbiomes, have developed rapidly and can offer novel insights into the essential pathophysiologic process of ACLF. In this paper, we briefly reviewed and summarized the current knowledge and recent advances in the definitions, criteria and prognostic assessments of ACLF; we also described the omics techniques and how omics-based analyses have been applied to investigate and characterize the biological mechanisms of ACLF and identify potential predictive biomarkers and therapeutic targets for ACLF. We also outline the challenges, future directions and limitations presented by omics-based analyses in clinical ACLF research.

Necroptosis is critical for regulating intestinal epithelial cells (IECs). Butyric acid (BA), produced during intestinal microbial metabolism, protects the intestinal epithelial barrier. However, whether necroptosis occurs in IECs during liver cirrhosis and whether sodium butyrate (NaB) can regulate necroptosis have not yet been reported. In this study, we aimed to investigate whether IECs undergo necroptosis in cirrhosis and whether NaB can regulate necroptosis and the related regulatory mechanisms.

Serum levels of RIPK3, MLKL, and Zonulin, as well as fecal BA levels, were measured and correlated in 48 patients with liver cirrhosis and 20 healthy controls. A rat model of liver cirrhosis was established, and NaB was administered. The expressions of MLKL, p-MLKL, and tight junction proteins were measured. We conducted an in vitro investigation of the effect of NaB on necroptosis in the HT29 cell line.

Serum levels of RIPK3, MLKL, and Zonulin in the liver cirrhosis group were higher, while fecal BA levels were lower than those in the control group. Zonulin levels were positively correlated with RIPK3 and MLKL levels, while fecal BA levels were negatively correlated with serum MLKL levels, but not with RIPK3 levels. NaB reduced the mRNA and protein expression of MLKL but had no effect on RIPK1 and RIPK3 in vitro. Rescue experiments demonstrated that NaB inhibited necroptosis through E2F1-mediated regulation of MLKL.

NaB alleviates intestinal mucosal injury and reduces necroptosis in IECs in liver cirrhosis. It also inhibits the necroptosis of IECs and protects the intestinal barrier by reducing E2F1 expression and downregulating MLKL expression levels. These results can be employed to develop a novel strategy for treating complications arising from liver cirrhosis.

The human gut microbiota, consisting of trillions of microorganisms, plays a crucial role in gastrointestinal (GI) health and disease. Dysbiosis, an imbalance in microbial composition, has been linked to a range of GI disorders, including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), celiac disease, and colorectal cancer. These conditions are influenced by the interactions between the gut microbiota, the host immune system, and the gut-brain axis. Recent research has highlighted the potential for microbiome-based therapeutic strategies, such as probiotics, prebiotics, fecal microbiota transplantation (FMT), and dietary modifications, to restore microbial balance and alleviate disease symptoms. This review examines the role of gut microbiota in the pathogenesis of common gastrointestinal diseases and explores emerging therapeutic approaches aimed at modulating the microbiome. We discuss the scientific foundations of these interventions, their clinical effectiveness, and the challenges in their implementation. The review underscores the therapeutic potential of microbiome-targeted treatments as a novel approach to managing GI disorders, offering personalized and alternative options to conventional therapies. As research in this field continues to evolve, microbiome-based interventions hold promise for improving the treatment and prevention of gastrointestinal diseases.

Tuberculosis (TB) is a major global health issue. Early diagnosis of TB is still a challenge. Studies are seeking non-sputum biomarker-based TB test. Emerging evidence indicates potential significance of blood microbiome signatures for diseases. However, blood microbiome RNA profiles are unknown in TB. We aimed to characterize the blood microbiome of TB patients and identify Mycobacterium tuberculosis (Mtb) genome-derived small RNA molecules to serve as diagnostic biomarkers for TB.

RNA sequencing data of the blood from TB patients and healthy controls were retrieved from the NCBI-SRA database for analyzing the blood microbiome and identifying rRNA-derived small RNA (rsRNA) of Mtb. Small RNA-seq was performed on plasma exosomes from TB patients and healthy controls. The levels of the candidate Mtb rsRNAs were determined by real-time quantitative reverse transcription PCR (RT-qPCR) on plasma from a separate cohort of 73 TB patients and 62 healthy controls.

The blood microbiome of TB patients consisted of RNA signals from bacteria, fungi, archaea, and viruses, with bacteria accounting for more than 97% of the total. Reduced blood microbial diversity and abundance of 6 Mycobacterium-associated bacterial genera, including Mycobacterium, Priestia, Nocardioides, Agrobacterium, Bradyrhizobium, and Escherichia, were significantly altered in the blood of TB patients. A diagnostic model for TB based on the 6 genera achieved an area under the curve (AUC) of 0.8945. rsRNAs mapped to the Mtb genome were identified from blood and plasma exosomes of TB patients. RT-qPCR results showed that 2 Mtb-derived rsRNAs, 16 S-L1 and 16 S-L2, could be used as diagnostic biomarkers to differentiate TB patients from healthy controls, with a high co-diagnostic efficacy (AUC = 0.7197).

A panel of blood microbiome signatures and Mtb-derived rsRNAs can serve as blood biomarkers for TB diagnosis.

Liver repair and regeneration are crucial physiological responses to hepatic injury and are orchestrated through intricate cellular and molecular networks. This review systematically delineates advancements in the field, emphasizing the essential roles played by diverse liver cell types. Their coordinated actions, supported by complex crosstalk within the liver microenvironment, are pivotal to enhancing regenerative outcomes. Recent molecular investigations have elucidated key signaling pathways involved in liver injury and regeneration. Viewed through the lens of metabolic reprogramming, these pathways highlight how shifts in glucose, lipid, and amino acid metabolism support the cellular functions essential for liver repair and regeneration. An analysis of regenerative variability across pathological states reveals how disease conditions influence these dynamics, guiding the development of novel therapeutic strategies and advanced techniques to enhance liver repair and regeneration. Bridging laboratory findings with practical applications, recent clinical trials highlight the potential of optimizing liver regeneration strategies. These trials offer valuable insights into the effectiveness of novel therapies and underscore significant progress in translational research. In conclusion, this review intricately links molecular insights to therapeutic frontiers, systematically charting the trajectory from fundamental physiological mechanisms to innovative clinical applications in liver repair and regeneration.

Alcohol abuse-triggered alcohol-related liver disease (ALD) has become as a global public health concern that substantially affects the well-being and clinical status of patients. Although modern medicine provides various treatments for ALD, their effectiveness is limited and can lead to adverse side effects. Probiotics have been employed to prevent, alleviate, and even treat ALD, with promising results. However, few comprehensive reviews are available on how they mitigate ALD by targeting the gut-liver axis. This review systematically clarifies the specific mediators of the gut-liver axis in healthy states. It also describes the alterations observed in ALD. Furthermore, this review thoroughly summarizes the underlying mechanisms through which probiotics act on the gut-liver axis to relieve ALD. It also discusses the current status and challenges faced in clinical research applications. Finally, we discuss the challenges and future prospects of using probiotics to treat ALD. This review improves our understanding of ALD and supports the development and application of probiotics that target the gut-liver axis for therapeutic use.

Alcohol consumption is a leading cause of preventable morbidity and mortality worldwide and the primary cause of advanced liver disease. Alcohol use disorder is a chronic, frequently relapsing condition characterized by persistent alcohol consumption despite its negative consequences. Alcohol-associated liver disease (ALD) encompasses a series of stages, from fatty liver (steatosis) to inflammation (steatohepatitis), fibrosis, and, ultimately, liver cirrhosis and its complications. The development of ALD is complex, involving both genetic and environmental factors, yet the exact mechanisms at play remain unclear. Alcohol-associated hepatitis (AH), a severe form of ALD, presents with sudden jaundice and liver failure. Currently, there are no approved targeted therapies able to interfere in the pathogenesis of ALD to stop the progression of the disease, making alcohol abstinence the most effective way to improve prognosis across all stages of ALD. For patients with advanced ALD who do not respond to medical therapy, liver transplantation is the only option that can improve prognosis. Recently, AH has become an early indication for liver transplantation in non-responders to medical treatment, showing promising results in carefully selected patients. This review provides an update on the epidemiology, natural history, pathogenesis, and current treatments for ALD. A deeper insight into novel targeted therapies investigated for AH focusing on new pathophysiologically-based agents is also discussed, including anti-inflammatory and antioxidative stress drugs, gut-liver axis modulators, and hepatocyte regenerative molecules.

Small Intestinal Bacterial Overgrowth (SIBO) has been implicated in the pathophysiology of chronic liver disease (CLD). We conducted a systematic review and meta-analysis to assess and compare the prevalence of SIBO among CLD patients (with and without with complications of end stage liver disease) and healthy controls.

Electronic databases were searched from inception up to July-2024 for case-control studies reporting SIBO in CLD. Prevalence rates, odds ratios (ORs), and 95% confidence intervals (CIs) of SIBO in patients with CLD and controls were calculated utilizing a random-effects model. The protocol was prospectively registered with PROSPERO (CRD42022379578).

The final dataset included 34 case-control studies with 2130 CLD patients and 1222 controls. Overall, the odds for SIBO prevalence in CLD patients compared to controls was 6.7 (95% CI 4.6-9.7, p < 0.001). Although the prevalence of SIBO among patients with CLD with cirrhosis was higher at 42.9% (95% CI: 35.9-50.2) compared to 36.9% (95% CI: 27.4-47.6) in those without cirrhosis, this difference failed statistical significance. However, CLD patients with decompensated cirrhosis had a significantly higher prevalence of SIBO compared to those with compensated cirrhosis, with an OR of 2.6 (95% CI: 1.5-4.5, p < 0.001). Additionally, the prevalence of SIBO was significantly higher in CLD patients with portal hypertension (PHT) than in those without PHT, with an OR of 2.1 (95% CI: 1.4-3.1, p < 0.001). The highest prevalence of SIBO was observed in patients with spontaneous bacterial peritonitis (SBP) (57.7%, 95% CI 38.8-74.5), followed by patients with hepatic encephalopathy (41.0%, 95% CI 16.0-72.3) and patients with variceal bleed (39.5%, 95% CI 12.1-75.6).

Overall, there is a significantly increased prevalence of SIBO in CLD patients compared to controls. The prevalence is even higher in CLD patients with PHT, especially those with SBP. This meta-analysis suggests that SIBO is associated with complications of CLD and potentially linked to the progression of CLD.

National Health and Medical Research Council, Centre for Research Excellence (APP170993).

Summaries of the relationships between the microbiota and liver cirrhosis and their conclusions are not consistent. This study describes microbial differences in patients with liver cirrhosis by performing a meta-analysis.

We searched PubMed, Embase, Web of Science, and the Cochrane Library and collected related articles published before March 10, 2024. Ratio of autochthonous to non-autochthonous taxa was calculated as the cirrhosis dysbiosis ratio (CDR). Using a random-effects model, the standard mean deviation (SMD) and 95% confidence interval (CI) were calculated. We subsequently performed subgroup, sensitivity, and publication bias analyses. cirrhosis dysbiosis ratio.

A total of 53 eligible papers including 5076 participants were included. The pooled estimates revealed a moderately significant reduction in gut microbiome richness in patients with liver cirrhosis compared with controls, including the Shannon, Chao1, observed species, ACE, and PD indices, but no significant difference was observed for the Simpson index. Over 80% of the studies reported significant differences in β diversity. Families Enterobacteriaceae and Pasteurellaceae, belonging to the phylum Proteobacteria, along with the family Streptococcaceae and the genera Haemophilus, Streptococcus, and Veillonella, were significantly associated with liver cirrhosis compared to the control group. In contrast, the healthy group exhibited a higher abundance of the class Clostridia, particularly the families Lachnospiraceae and Ruminococcaceae, which are known for their diversity and role as common gut commensals. Furthermore, the class Bacilli, predominantly represented by the genus Streptococcus, was markedly enriched in the cirrhosis group.

The microbiota richness of liver cirrhosis patients was lower than that of healthy controls. Alterations in gut microbiota linked to liver cirrhosis were characterized by a decrease in Lachnospiraceae, Ruminococcaceae, and Clostridia and an enrichment of Enterobacteriaceae, Pasteurellaceae, Streptococcaceae, Bacilli, and Streptococcus.

The interplay between multiple organs, known as inter-organ crosstalk, represents a complex and essential research domain in understanding the mechanisms and therapies for kidney diseases. The kidneys not only interact pathologically with many other organs but also communicate with other systems through various signaling pathways. It is of paramount importance to comprehend these mechanisms for the development of more efficient therapeutic strategies. Despite extensive research in IgA nephropathy (IgAN), the most common kidney disease, the elaboration mechanism of IgAN remains challenging. Numerous studies suggest that alterations in the intestinal microbiome and its metabolites are pivotal in the progression of IgAN, opening new avenues for understanding its mechanisms. Interestingly, certain presumed probiotics, such as Akkermansia muciniphila, have been implicated in the onset of IgAN, making the exploration of gut microbiota in the context of IgAN pathogenesis even more intriguing. In this review, we summarize the status of gut microbiology studies of IgAN and explore the possible mechanisms and intervention prospects. Future research and treatment directions may increasingly emphasize systemic, multi-organ combined interventions to decelerate the advancement of kidney disease and enhance the overall prognosis of patients.

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

The last two decades have witnessed an explosion of microbiome research, including in hepatology, with studies demonstrating altered microbial composition in liver disease. More recently, efforts have been made to understand the association of microbiome features with clinical outcomes and to develop therapeutics targeting the microbiome. While microbiome therapeutics hold much promise, their unique features pose certain challenges for the design and conduct of clinical trials. Herein, we will briefly review indications for microbiome therapeutics in cirrhosis, currently available microbiome therapeutics, and the biological pathways targeted by these therapies. We will then focus on the best practices and important considerations for clinical trials of gut microbiome therapeutics in cirrhosis.

The short-term mortality of severe alcoholic-associated hepatitis (SAH) is high, but there are no effective treatments to improve short-term mortality other than corticosteroids. This study investigated the effects of adding rifaximin to standard treatment in patients with SAH.

In this randomized controlled open-label trial, patients with SAH (Maddrey's discriminant function≥32) were randomized to the rifaximin or control group. Patients were simultaneously treated with corticosteroid or pentoxifylline as standard treatment for 4 weeks. Randomization was stratified by SAH treatment.

A total of 50 patients were enrolled in this study (29 in the control group and 21 in the rifaximin group). The mean Model for End-stage Liver Disease (MELD) scores were 24.4 and 27.5 in the control and rifaximin groups, respectively (P = 0.106). There were no significant differences in 6-month Liver Transplantation (LT)-free survival rate between the two groups (P = 0.502). When stratified by SAH treatment, there was no significant difference in 6-month LT-free survival rate between the control and rifaximin treatment groups (P = 0.186 in the corticosteroid group and P = 0.548 in the pentoxifylline group). There were no significant differences in the occurrence of liver-related complications between the two groups (all Ps>0.05). The MELD score was the only independent factor for 6-month LT-free survival (hazard ratio 1.188, 95 % confidence interval 1.094-1.289, P<0.001), and rifaximin was not.

In patients with SAH, adding rifaximin to corticosteroid or pentoxifylline had no survival benefit and no preventive effect on the development of liver-related complications. The MELD score was the only significant factor for short-term mortality.

The study was registered on ClinicalTrials.gov (number: NCT02485106).

Antibiotics are commonly used to treat infectious diseases; however, persistence is often expressed by the pathogenic bacteria and their long-term relative effect on the host have been neglected. The present study investigated the impact of antibiotics in gut microbiota (GM) and metabolism of host. The effect of ampicillin antibiotics on GM of Drosophila melanogaster was analyzed through deep sequencing of 16S rRNA amplicon gene. The dominant phyla consisted of Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Planctomycetes, Chloroflexi, Euryarchaeota, Acedobacteria, Verrucomicrobia, and Cyanobacteria. It was found that the composition of GM was significantly altered on administration of antibiotics. On antibiotic treatments, there were decline in relative abundance of Proteobacteria and Firmicutes, while there were increase in relative abundance of Chlorophyta and Bacteroidota. High abundance of 14 genera, viz., Wolbachia, Lactobacillus, Bacillus, Pseudomonas, Thiolamprovum, Pseudoalteromonas, Vibrio, Romboutsia, Staphylococcus, Alteromonas, Clostridium, Lysinibacillus, Litoricola, and Cellulophaga were significant (p ≤ 0.05) upon antibiotic treatment. Particularly, the abundance of Acetobacter was significantly (p ≤ 0.05) declined but increased for Wolbachia. Further, a significant (p ≤ 0.05) increase in Wolbachia endosymbiont of D. melanogaster, Wolbachia endosymbiont of Curculio okumai, and Wolbachia pipientis and a decrease in the Acinetobacter sp. were observed. We observed an increase in functional capacity for biosynthesis of certain nucleotides and the enzyme activities. Further, the decrease in antimicrobial peptide production in the treated group and potential effects on the host's defense mechanisms were observed. This study helps shed light on an often-overlooked dimension, namely the persistence of antibiotics' effects on the host.

It has been reported that the gut-liver axis and intestinal microbiome contribute crucially to different liver diseases. So, targeting this hepato-intestinal connection may provide a novel treatment modality for hepatic disorders such as drug-induced liver injury (DILI). The present study thought to investigate the protective effect of turmeric (TUR) on metronidazole (MNZ)-induced liver damage and the possible association of the gut-liver axis and gut microbiota as a suggested underlying mechanism. In the first experiment, a MNZ-induced liver injury rat model was reproduced after 130 mg/kg oral MNZ administration for 30 days. Meanwhile, the treatment group was orally treated with 100 mg/kg turmeric daily. In the second experiment, fecal microbiome transplantation (FMT) was conducted, in which the fecal microbiome of each group in the first experiment was transplanted to a healthy corresponding group in the second experiment. The liver enzymes (aminotransferase (ALT) and aspartate aminotransferase (AST)) and histopathological examination were estimated to assess liver function. Inflammatory cytokines and oxidative markers were evaluated in the liver tissues. Histological analysis, intestinal barrier markers, and expression of tight junction proteins were measured for assessment of the intestinal injury. Changes in the gut microbial community and possible hepatic bacterial transmission were analyzed using 16S rRNA sequencing. MNZ induced intestinal and liver injuries which were significantly improved by turmeric. Increased firmicutes/bacteroidetes ratio and bacterial transmission due to gut barrier disruption were suggested. Moreover, TUR has maintained the gut microbial community by rebalancing and restoring bacterial proportions and abundance, thereby repairing the gut mucosal barrier and suppressing bacterial translocation. TUR protected against MNZ-induced gut barrier disruption. Reshaping of the intestinal bacterial composition and prohibition of the hepatic microbial translocation were suggested turmeric effects, potentially mitigating MNZ-related liver toxicity.

Over the last few decades, there have been tremendous advances in our understanding of the role of the gut microbiome in cirrhosis and the clinical sequelae that follow. Progressive dysbiosis and immune dysregulation occur in patients with cirrhosis. In fact, alterations in the gut microbiome occur long before a diagnosis of cirrhosis is made. Understandably, our attention has recently been diverted toward potential modulators of the gut microbiome and the gut-liver axis as targets for treatment. The goal of this review is to highlight the utility of manipulating the gut microbiome with a focus on fecal microbiome transplantation (FMT) in patients with cirrhosis. In addition, we will provide an overview of disease-specific microbial alterations and the resultant impact this has on cirrhosis-related complications.

Hepatic encephalopathy (HE) is a common condition in patients with cirrhosis, representing the second most frequent cause of decompensation. Approximately 30-40% of patients with cirrhosis will experience overt HE during the clinical course of their illness. In most cases, it is possible to identify a precipitating or risk factor for HE. These are distinct concepts that play different roles in the development of this condition. While precipitating factors act acutely, risk factors are generally present over an extended period and contribute to the overall likelihood of developing HE. The two types of factors require different approaches, with risk factors being more susceptible to prevention. The aim of this review is to describe the most important risk factors (such as severity of liver disease, previous episode of HE, minimal/covert HE, spontaneous and iatrogenic shunt, malnutrition, chronic therapies, metabolic diseases) for the development of HE and how to prevent it.

The prevalence and mortality related to end-stage liver disease (ESLD) continue to rise globally. Liver transplant (LT) recipients continue to be older and have inherently more comorbidities. Among these, cardiac disease is one of the three main causes of morbidity and mortality after LT. Several reasons exist including the high prevalence of associated risk factors, which can also be attributed to the rise in the proportion of patients undergoing LT for metabolic dysfunction-associated steatohepatitis (MASH). Additionally, as people age, the prevalence of now treatable cardiac conditions, including coronary artery disease (CAD), cardiomyopathies, significant valvular heart disease, pulmonary hypertension, and arrhythmias rises, making the need to treat these conditions critical to optimize outcomes. There is an emerging body of literature regarding CAD screening in patients with ESLD, however, there is a paucity of strong evidence to support the guidance regarding the management of cardiac conditions in the pre-LT and perioperative settings. This has resulted in significant variations in assessment strategies and clinical management of cardiac disease in LT candidates between transplant centres, which impacts LT candidacy based on a transplant centre's risk tolerance and comfort level for caring for patients with concomitant cardiac disease. Performing a comprehensive assessment and understanding the potential approaches to the management of ESLD patients with cardiac conditions may increase the acceptance of patients, who appear too complex, but rather require extra evaluation and may be reasonable candidates for LT. The unique physiology of ESLD can profoundly influence preoperative assessment, perioperative management, and outcomes associated with underlying cardiac pathology, and requires a thoughtful multidisciplinary approach. The strategies proposed in this manuscript attempt to review the latest expert experience and opinions and provide guidance to practicing clinicians who assess and treat patients being considered for LT. These topics also highlight the gaps that exist in the comprehensive care of LT patients and the need for future investigations in this field.

Frailty in cirrhosis or advanced chronic liver disease (ACLD) is a relevant prognostic factor. In the present study, we aimed to analyze potential biomarkers associated with frailty and its improvement in patients with ACLD. We analyzed the serum of outpatients with ACLD who participated in a previous study (Román, Hepatol Commun 2024) in which frailty was assessed using the liver frailty index (LFI), and patients who were frail or prefrail were randomized to a multifactorial intervention (home exercise, branched-chain amino acids, and probiotics) or control for 12 months. We determined a biomarker battery of inflammation, bacterial translocation, and liver damage in blood and urine and blood metabolomics by 1H-NMR. Thirty-seven patients were included. According to the LFI, 32 patients were frail or prefrail, and 5 were robust. At baseline, LFI correlated with LBP, sCD163, mtDNA, FGF-21, urinary NGAL, urinary claudin-3, and the metabolites mannose, ethanol, and isoleucine. During the study, patients in the intervention group showed an improvement in LFI and a decrease in CRP, LBP, sCD163, and ccK18 compared to the control group. Metabolomics showed a decrease in dimethyl sulfone and creatinine and an increase in malonate, ornithine, isoleucine, and valine in the intervention group. We conclude that frailty in patients with ACLD is associated with biomarkers of systemic inflammation, bacterial translocation, and liver damage, and alterations of amino acid and short-chain fatty acid metabolism.

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.

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

Primary biliary cholangitis (PBC) is associated closely with the gut microbiota. This study aimed to explore the characteristics of the gut microbiota after the progress of PBC to cirrhosis.

This study focuses on utilizing the 16S rRNA gene sequencing method to screen for differences in gut microbiota in PBC patients who progress to cirrhosis. Then, we divided the data into training and verification sets and used seven different machine learning (ML) models to validate them respectively, calculating and comparing the accuracy, F1 score, precision, and recall, and screening the dominant intestinal flora affecting PBC cirrhosis.

PBC cirrhosis patients showed decreased diversity and richness of gut microbiota. Additionally, there are alterations in the composition of gut microbiota in PBC cirrhosis patients. The abundance of Faecalibacterium and Gemmiger bacteria significantly decreases, while the abundance of Veillonella and Streptococcus significantly increases. Furthermore, machine learning methods identify Streptococcus and Gemmiger as the predominant gut microbiota in PBC patients with cirrhosis, serving as non-invasive biomarkers (AUC = 0.902).

Our study revealed that PBC cirrhosis patients gut microbiota composition and function have significantly changed. Streptococcus and Gemmiger may become a non-invasive biomarker for predicting the progression of PBC progress to cirrhosis.