Fecal microbiota transplant from a rational stool donor improves hepatic encephalopathy: A randomized clinical trial

Non-Invasive Biomarkers for Differentiating Alcohol Associated Hepatitis from Acute Decompensation in Patients with ALD

Alcohol-associated hepatitis (AH) is the most severe form of alcohol-related liver disease. The natural course of alcohol-related liver disease is influenced by heavy alcohol consumption and abstinence periods. Differentiating between AH and decompensated cirrhosis (DC) could be extremely challenging in clinical practice due to clinical and bioclinical similarities. The severity of AH is made on bioclinical grounds, the severe form necessitating corticotherapy treatment. Liver biopsy is still the standard of care for establishing the diagnosis in atypical presentations. The pathogenesis of AH is an interplay between gene expression, cytokine dysregulation, the immune system and the gut microbiota. Non-invasive tests are increasingly and widely used for the purpose of early diagnosis and reliable prognostication. The non-invasive tests are emerging in concordance with disease pathogenesis. In this review, we describe the non-invasive tools that can distinguish AH from DC. We outline the available cut-offs and their performance in diagnosis and prognosis, as well as in assessing the treatment response to corticotherapy. Promising circulating biomarkers like keratin 18, microRNAs and sphingolipids will be in the review.

Therapeutic manipulation of the microbiome in liver disease

Myriad associations between the microbiome and various facets of liver physiology and pathology have been described in the literature. Building on descriptive and correlative sequencing studies, metagenomic studies are expanding our collective understanding of the functional and mechanistic role of the microbiome as mediators of the gut-liver axis. Based on these mechanisms, the functional activity of the microbiome represents an attractive, tractable, and precision medicine therapeutic target in several liver diseases. Indeed, several therapeutics have been used in liver disease even before their description as a microbiome-dependent approach. To bring successful microbiome-targeted and microbiome-inspired therapies to the clinic, a comprehensive appreciation of the different approaches to influence, collaborate with, or engineer the gut microbiome to coopt a disease-relevant function of interest in the right patient is key. Herein, we describe the various levels at which the microbiome can be targeted-from prebiotics, probiotics, synbiotics, and antibiotics to microbiome reconstitution and precision microbiome engineering. Assimilating data from preclinical animal models, human studies as well as clinical trials, we describe the potential for and rationale behind studying such therapies across several liver diseases, including metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, cirrhosis, HE as well as liver cancer. Lastly, we discuss lessons learned from previous attempts at developing such therapies, the regulatory framework that needs to be navigated, and the challenges that remain.

Fecal microbiota transplantation: current challenges and future landscapes

SUMMARYGiven the importance of gut microbial homeostasis in maintaining health, there has been considerable interest in developing innovative therapeutic strategies for restoring gut microbiota. One such approach, fecal microbiota transplantation (FMT), is the main "whole gut microbiome replacement" strategy and has been integrated into clinical practice guidelines for treating recurrent Clostridioides difficile infection (rCDI). Furthermore, the potential application of FMT in other indications such as inflammatory bowel disease (IBD), metabolic syndrome, and solid tumor malignancies is an area of intense interest and active research. However, the complex and variable nature of FMT makes it challenging to address its precise functionality and to assess clinical efficacy and safety in different disease contexts. In this review, we outline clinical applications, efficacy, durability, and safety of FMT and provide a comprehensive assessment of its procedural and administration aspects. The clinical applications of FMT in children and cancer immunotherapy are also described. We focus on data from human studies in IBD in contrast with rCDI to delineate the putative mechanisms of this treatment in IBD as a model, including colonization resistance and functional restoration through bacterial engraftment, modulating effects of virome/phageome, gut metabolome and host interactions, and immunoregulatory actions of FMT. Furthermore, we comprehensively review omics technologies, metagenomic approaches, and bioinformatics pipelines to characterize complex microbial communities and discuss their limitations. FMT regulatory challenges, ethical considerations, and pharmacomicrobiomics are also highlighted to shed light on future development of tailored microbiome-based therapeutics.

Evaluation of the Suitability of Selecting a Faecal Microbiota Transplant: Bacterial Composition and Subsequent Long-Term Monitoring of the Viability of Its Frozen and Lyophilised Forms

Objectives: The aim of this study was to confirm the effectiveness of FMT on the basis of optimum composition of the faecal microbiota of the donor for support therapy in patients with ulcerative colitis, and to observe the viability of the microbiota in frozen and lyophilised administration forms of FMT under various storage conditions. Methods: The bacterial microbiota composition of the FMT samples was assessed using amplicon sequencing via next-generation sequencing (NGS) technology, conducted on the Illumina MiSeq platform. The BD FACS Canto flow cytometer was used to analyse the metabolic activity of FMT samples. Results: FMT analysis confirmed the presence of key butyrate-producing organisms, specifically highlighting species such as Bifidobacterium adolescentis, Faecalibacterium prausnitzi, Coprococcus catus, Eubacterium rectale, alongside contributions from genera Roseburia and Blautia. These organisms play a crucial role in maintaining intestinal health in humans. The viable microorganism counts were significantly higher (p < 0.001) in the frozen form of FMT (−70 °C) in comparison to lyophilised forms (−70 °C, 4 °C and 20 °C) throughout the storage period. Conclusion: The conducted NGS analyses allowed us to confirm the suitability of our FMT donor as a potential candidate for the target group of patients diagnosed with ulcerative colitis. From the point of view of optimum utilisation of FMT at its highest metabolic activity for the purpose of transplantation, its storage for a maximum of 2 months under specified conditions was confirmed as the most suitable for the frozen and all lyophilised FMT forms.

Hepatic encephalopathy: a neurologist's perspective

Liver disease is increasingly common, estimated to affect over 25% of the world's population. Failure of the liver to maintain a normal metabolic milieu leads to impaired brain function (hepatic encephalopathy), and conditions that cause liver disease can themselves predispose to neurological disease. As neurologists' involvement with the acute take increases, it is important that we are familiar with the neurological complications of liver disease, their investigation and management, and to know which other neurological diseases occur in this patient population. In this article, we review the causes, presentation and treatment of hepatic encephalopathy, and discuss important differential diagnoses in patients with liver disease who present with neurological disturbance.

Fecal microbiota transplantation in the treatment of hepatic encephalopathy: A perspective

Due to its complex pathogenesis, treatment of hepatic encephalopathy (HE) continues to be a therapeutic challenge. Of late, gut microbiome has garnered much attention for its role in the pathogenesis of various gastrointestinal and liver diseases and its potential therapeutic use. New evidence suggests that gut microbiota plays a significant role in cerebral homeostasis. Alteration in the gut microbiota has been documented in patients with HE in a number of clinical and experimental studies. Research on gut dysbiosis in patients with HE has opened newer therapeutic avenues in the form of probiotics, prebiotics and the latest fecal microbiota transplantation (FMT). Recent studies have shown that FMT is safe and could be effective in improving outcomes in advanced liver disease patients presenting with HE. However, questions over the appropriate dose, duration and route of administration for best treatment outcome remains unsettled.

Recent advances in the prevention and treatment of decompensated cirrhosis and acute-on-chronic liver failure (ACLF) and the role of biomarkers

The progression of cirrhosis with clinically significant portal hypertension towards decompensated cirrhosis remains clinically challenging and the evolution towards acute-on-chronic liver failure (ACLF), with one or more extrahepatic organ failures, is associated with very high mortality. In the last decade, significant progress has been made in the understanding of the mechanisms leading to decompensation and ACLF. As portal hypertension advances, bacterial translocation across an impaired gut barrier culminates in endotoxaemia, systemic inflammation and cirrhosis-associated immune dysfunction (CAID). Gut-derived systemic inflammation and CAID have become the logical targets for innovative therapies that prevent hepatic decompensation episodes and the progression to ACLF.Furthermore, classification of disease and biomarker discovery to personalise care have advanced in the field. This review discusses progress in biomarker discovery and personalisation of treatment in decompensated cirrhosis and ACLF.

The Health Care Burden of Hepatic Encephalopathy

Hepatic encephalopathy-a common and debilitating complication of cirrhosis-results in major health care burden on both patients and caregivers through direct and indirect costs. In addition to risk of falls, inability to work and drive, patients with hepatic encephalopathy often require hospital admission (and often readmission), and many require subacute care following hospitalization. The costs and psychological impact of liver transplantation often ensue. As the prevalence of chronic liver disease increases throughout the United States, the health care burden of hepatic encephalopathy will continue to grow.

Minimal Hepatic Encephalopathy

Minimal hepatic encephalopathy (MHE) is a pervasive frequent complication of cirrhosis of any etiology. The diagnosis of MHE is difficult as the standard neurologic examination is essentially within normal limits. None of the symptoms and signs of overt HE is present in a patient with MHE, such as confusion, disorientation, or asterixis. Progress has been made in diagnostic tools for detection of attention and cognitive deficits at the point of care of MHE. The development of MHE significantly impacts quality of life and activities of daily life in affected patients including driving motor vehicles and machine operation.

Pathophysiology of Hepatic Encephalopathy: A Framework for Clinicians

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that is observed primarily in patients with liver disease. The pathophysiology is complex and involves many factors including ammonia toxicity, dysregulation of central nervous system activity, and excess inflammatory cytokines. Symptoms of HE range from subclinical to debilitating. HE can be difficult to treat and represents a large burden to patients, their caregivers, and the health-care system because of associated resource utilization. This review article provides an overview of the current understanding of the pathophysiology behind HE and where the current research and treatments are pointing toward.

Preventing Readmissions of Hepatic Encephalopathy: Strategies in the Acute Inpatient, Immediate Postdischarge, and Longitudinal Outpatient Setting

Hepatic encephalopathy (HE) is a strong predictor of early hospital readmission in patients with cirrhosis. Early hospital readmission increases health care costs and is associated with worse survival. Herein we provide an overview of strategies to prevent hospital readmissions in patients with HE, divided into 3 contexts: (a) acute inpatient, (b) immediate postdischarge, and (c) longitudinal outpatient setting.

Nontraditional Treatment of Hepatic Encephalopathy

The pathophysiology of hepatic encephalopathy (HE) is complex, with hyperammonemia playing a central role in its development. Traditional therapies for HE have targeted ammonia and include medications such as lactulose and rifaximin. Although these agents are considered standard of care, nontraditional treatments seek to affect other factors in the pathogenesis of HE. Finally, procedural therapies include albumin dialysis, shunt closure, and the ultimate cure for HE, which is liver transplant. The treatments discussed provide alternative options for patients who have failed standard of care. However, more high-quality studies are needed to routinely recommend many of these agents.

Pharmacologic Management of Hepatic Encephalopathy

Hepatic encephalopathy is a common cause of morbidity and mortality among patients with decompensated liver cirrhosis. In this article, we review the history, mechanism, and evidence for first-line pharmacologic therapies for hepatic encephalopathy including nonabsorbable disaccharides, antibiotics, and electrolyte management. We also review newer, second-line therapies including polyethylene glycol, albumin, branched-chain amino acids, probiotics and fecal microbiota transplant, zinc, and l-ornithine-l-aspartate.

Safety profile and effects on the peripheral immune response of fecal microbiota transplantation in clinically healthy dogs

BACKGROUND

Fecal microbiota transplantation (FMT) is increasingly used for gastrointestinal and extra-gastrointestinal diseases in veterinary medicine. However, its effects on immune responses and possible adverse events have not been systematically investigated.

HYPOTHESIS/OBJECTIVES

Determine the short-term safety profile and changes in the peripheral immune system after a single FMT administration in healthy dogs.

ANIMALS

Ten client-owned, clinically healthy dogs as FMT recipients, and 2 client-owned clinically healthy dogs as FMT donors.

METHODS

Prospective non-randomized clinical trial. A single rectal enema of 5 g/kg was given to clinically healthy canine recipients. During the 28 days after FMT administration, owners self-reported adverse events and fecal scores. On Days 0 (baseline), 1, 4, 10, and 28 after FMT, fecal and blood samples were collected. The canine fecal dysbiosis index (DI) was calculated using qPCR.

RESULTS

No significant changes were found in the following variables: CBC, serum biochemistry, C-reactive protein, serum cytokines (interleukins [IL]-2, -6, -8, tumor necrosis factor [TNF]-α), peripheral leukocytes (B cells, T cells, cluster of differentiation [CD]4+ T cells, CD8+ T cells, T regulatory cells), and the canine DI. Mild vomiting (n = 3), diarrhea (n = 4), decreased activity (n = 2), and inappetence (n = 1) were reported, and resolved without intervention.

CONCLUSIONS AND CLINICAL IMPORTANCE

Fecal microbiota transplantation did not significantly alter the evaluated variables and recipients experienced minimal adverse events associated with FMT administration. Fecal microbiota transplantation was not associated with serious adverse events, changes in peripheral immunologic variables, or the canine DI in the short-term.

Future Therapies of Hepatic Encephalopathy

Hepatic encephalopathy, either covert or overt, affects more than half of patients with cirrhosis and has lasting effects even after portal hypertension is corrected. Unfortunately, the current therapeutic options still result in high rates of relapse and progression, in part owing to cost barriers and side effects, leading to poor adherence. This review summarizes emerging treatment options, which could take advantage of alternative disease pathways to improve future care of those with hepatic encephalopathy.

Research reviews and prospects of gut microbiota in liver cirrhosis: a bibliometric analysis (2001-2023)

INTRODUCTION

The gut-liver axis has emerged as a focal point in chronic liver disorders, prompting more research into the role of the gut microbiota in liver cirrhosis. In individuals with liver cirrhosis, changes in the structure and function of the gut microbiota are closely tied to clinical prognosis. However, there is a scarcity of bibliometric evaluations conducted in this particular field.

METHODS

This study is aiming to conduct a complete analysis of the knowledge structure and centers pertaining to gut microbiota in liver cirrhosis using bibliometric methods. Publications on gut microbiota and liver cirrhosis from 2001 to 2023 are sourced from the Web of Science Core Collection. For the bibliometric analysis, we employ VOSviewer, CiteSpace, and the R package "bibliometrix".

RESULTS

Our study encompasses a comprehensive collection of 3109 articles originating from 96 countries, with notable contributions from leading nations such as the United States and China. The quantity of publications concerning the gut microbiota of liver cirrhosis rises annually. The University of California San Diego, Virginia Commonwealth University, Zhejiang University are the primary research institutions. World Journal of Gastroenterology publishes the most papers in this field, while hepatology is the most frequently co-cited journal. These publications come from a total of 15,965 authors, and the most prolific authors are Bajaj Jasmohan S., Schnabl Bernd and Gillevet Patrick M., while the most co-cited authors are Bajaj Jasmohan S., Younossi Zobair M., and Reiner Wiest. In addition, "dysbiosis", "gut microbiota", "intestinal barrier", "fecal microbiota transplantation", and "complement-system" are the primary keywords of research trends in recent years.

DISCUSSION

This study offering a comprehensive insight into the research dynamics surrounding gut microbiota in patients with liver cirrhosis. It delineates the current research frontiers and hotspots, serving as a valuable guide for scholars.

The assessment and management of cirrhotic patients with encephalopathy

Hepatic encephalopathy (HE) is a debilitating complication associated with both acute and chronic liver injury. It is associated with a greater risk of death than any other significant hepatic decompensation event. It manifests as a wide spectrum of neuropsychological abnormalities ranging from subtle impairments in higher cognitive function, to confusion and coma. The pathophysiological role of ammonia in the development of HE is well known, but there is increasing recognition that the gut microbiome, gut-derived systemic inflammation and development of infection can serve as drivers of HE in patients with cirrhosis. The development of HE portents to the severity of cirrhosis and the prognosis is poor without liver transplantation. A referral for liver transplantation should therefore be considered early in those who are eligible. This review covers the pragmatic assessment of HE in patients with cirrhosis, as well as the current evidence base for the best practice management of HE in such patients.

Role of the portal system in liver regeneration: From molecular mechanisms to clinical management

The liver has a strong regenerative capacity that ensures patient recovery after hepatectomy and liver transplantation. The portal system plays a crucial role in the dual blood supply to the liver, making it a significant factor in hepatic function. Several surgical strategies, such as portal vein ligation, associating liver partition and portal vein ligation for staged hepatectomy, and dual vein embolization, have highlighted the portal system's importance in liver regeneration. Following hepatectomy or liver transplantation, the hemodynamic properties of the portal system change dramatically, triggering regeneration via shear stress and the induction of hypoxia. However, excessive portal hyperperfusion can harm the liver and negatively affect patient outcomes. Furthermore, as the importance of the gut-liver axis has gradually been revealed, the effect of metabolites and cytokines from gut microbes carried by portal blood on liver regeneration has been acknowledged. From these perspectives, this review outlines the molecular mechanisms of the portal system's role in liver regeneration and summarizes therapeutic strategies based on the portal system intervention to promote liver regeneration.

Hepatic encephalopathy: From novel pathogenesis mechanism to emerging treatments

Hepatic encephalopathy (HE) is one of the major complications of liver disease and significantly affects the quality of life (QOL) of patients. HE is common and frequently relapses in cirrhotic patients. The management of HE is supportive, and precipitating conditions should be eliminated. Most drugs used to treat HE are conventional and include nonabsorbable disaccharides such as lactulose, and antibiotics such as rifaximin. However, their therapeutic efficacy is still suboptimal, and novel therapeutic agents are urgently needed. In addition, the optimal management and diagnosis of minimal HE/covert HE are under debate. In this review, we focus on novel pathogenetic mechanisms such as central nervous system clearance, and emerging therapeutic targets of HE, such as fecal material transplantation. We also discuss different classifications and etiologies of HE.

Faecal hsa-miR-7704 inhibits the growth and adhesion of Bifidobacterium longum by suppressing ProB and aggravates hepatic encephalopathy

Both gut microbiome and microRNAs (miRNAs) play a role in the development of hepatic encephalopathy (HE). However, the functional link between the microbiome and host-derived miRNAs in faeces remains poorly understood. In the present study, patients with HE had an altered gut microbiome and faecal miRNAs compared with patients with chronic hepatitis B. Transferring faeces and faecal miRNAs from patients with HE to the recipient mice aggravated thioacetamide-induced HE. Oral gavage of hsa-miR-7704, a host-derived miRNA highly enriched in faeces from patients with HE, aggravated HE in mice in a microbiome-dependent manner. Mechanistically, hsa-miR-7704 inhibited the growth and adhesion of Bifidobacterium longum by suppressing proB. B. longum and its metabolite acetate alleviated HE by inhibiting microglial activation and ammonia production. Our findings reveal the role of miRNA-microbiome axis in HE and suggest that faecal hsa-miR-7704 are potential regulators of HE progression.

BDNF/CREB signaling pathway contribution in depression pathogenesis: A survey on the non-pharmacological therapeutic opportunities for gut microbiota dysbiosis

Emerging evidence supports the gut microbiota and the brain communication in general health. This axis may affect behavior through modulating neurotransmission, and thereby involve in the pathogenesis and/or progression of different neuropsychiatric disorders such as depression. Brain-derived neurotrophic factor and cAMP response element-binding protein known as CREB/BDNF pathway plays have critical functions in the pathogenesis of depression as the same of mechanisms related to antidepressants. However, the putative causal significance of the CREB/BDNF signaling cascade in the gut-brain axis in depression remains unknown. Also interventions such as probiotics supplementation and exercise can influence microbiome also improve bidirectional communication of gut and brain. In this review we aim to explain the BDNF/CREB signaling pathway and gut microbiota dysfunction and then evaluate the potential role of probiotics, prebiotics, and exercise as a therapeutic target in the gut microbiota dysfunction induced depression. The current narrative review will specifically focus on the impact of exercise and diet on the intestinal microbiota component, as well as the effect that these therapies may have on the microbiota to alleviate depressive symptoms. Finally, we look at how BDNF/CREB signaling pathway may exert distinct effects on depression and gut microbiota dysfunction.

Alcohol-associated liver disease

Alcohol-associated liver disease (ALD) is a major cause of chronic liver disease worldwide, and comprises a spectrum of several different disorders, including simple steatosis, steatohepatitis, cirrhosis, and superimposed hepatocellular carcinoma. Although tremendous progress has been made in the field of ALD over the last 20 years, the pathogenesis of ALD remains obscure, and there are currently no FDA-approved drugs for the treatment of ALD. In this Review, we discuss new insights into the pathogenesis and therapeutic targets of ALD, utilizing the study of multiomics and other cutting-edge approaches. The potential translation of these studies into clinical practice and therapy is deliberated. We also discuss preclinical models of ALD, interplay of ALD and metabolic dysfunction, alcohol-associated liver cancer, the heterogeneity of ALD, and some potential translational research prospects for ALD.

Gut-Liver-Brain Axis and Alcohol Use Disorder: Treatment Potential of Fecal Microbiota Transplantation

PURPOSE

Chronic alcohol use is a major cause of liver damage and death. In the United States, multiple factors have led to low utilization of pharmacotherapy for alcohol use disorder (AUD), including lack of provider knowledge and comfort in prescribing medications for AUD. Alcohol consumption has direct effects on the gut microbiota, altering the diversity of bacteria and leading to bacterial overgrowth. Growing evidence suggests that alcohol's effects on the gut microbiome may contribute to increased alcohol consumption and progression of alcohol-associated liver disease (ALD). This article reviews human and preclinical studies investigating the role of fecal microbiota transplantation (FMT) in ameliorating alcohol-associated alterations to the liver, gut, and brain resulting in altered behavior; it also discusses the therapeutic potential of FMT.

SEARCH METHODS

For this narrative review, a literature search was conducted in September 2022 of PubMed, Web of Science Core Collection, and Google Scholar to identify studies published between January 2012 and September 2022. Search terms used included "fecal microbiota transplantation" and "alcohol."

SEARCH RESULTS

Most results of the literature search were review articles or articles on nonalcoholic fatty liver disease; these were excluded. Of the remaining empirical manuscripts, very few described clinical or preclinical studies that were directly investigating the effects of FMT on alcohol drinking or related behaviors. Ultimately, 16 studies were included in the review.

DISCUSSION AND CONCLUSIONS

The literature search identified only a few studies that were directly investigating the effect of FMT on ALD or alcohol drinking and related behaviors. Largely proof-of-concept studies, these findings demonstrate that alcohol can alter the gut microbiome and that the microbiome can be transferred between humans and rodents to alter affective behaviors frequently associated with increased alcohol use. Other studies have shown promise of FMT or other probiotic supplementation in alleviating some of the symptoms associated with ALD and drinking. These results show that the implementation of FMT as a therapeutic approach is still in the investigatory stages.

Role of fecal microbiota transplant in management of hepatic encephalopathy: Current trends and future directions

Fecal microbiota transplantation (FMT) offers a potential treatment avenue for hepatic encephalopathy (HE) by leveraging beneficial bacterial displacement to restore a balanced gut microbiome. The prevalence of HE varies with liver disease severity and comorbidities. HE pathogenesis involves ammonia toxicity, gut-brain communication disruption, and inflammation. FMT aims to restore gut microbiota balance, addressing these factors. FMT's efficacy has been explored in various conditions, including HE. Studies suggest that FMT can modulate gut microbiota, reduce ammonia levels, and alleviate inflammation. FMT has shown promise in alcohol-associated, hepatitis B and C-associated, and non-alcoholic fatty liver disease. Benefits include improved liver function, cognitive function, and the slowing of disease progression. However, larger, controlled studies are needed to validate its effectiveness in these contexts. Studies have shown cognitive improvements through FMT, with potential benefits in cirrhotic patients. Notably, trials have demonstrated reduced serious adverse events and cognitive enhancements in FMT arms compared to the standard of care. Although evidence is promising, challenges remain: Limited patient numbers, varied dosages, administration routes, and donor profiles. Further large-scale, controlled trials are essential to establish standardized guidelines and ensure FMT's clinical applications and efficacy. While FMT holds potential for HE management, ongoing research is needed to address these challenges, optimize protocols, and expand its availability as a therapeutic option for diverse hepatic conditions.

Body Composition in Chronic Liver Disease

Body composition has recently been attracting people's attention, not only from a cosmetic standpoint but also from the perspective of health and longevity. The body is classified into three components: fat, bone, and lean soft tissue, and it is common to see an increase in body fat and a decrease in total body muscle mass with aging. Aging-related loss of muscle mass and muscle function is referred to as primary sarcopenia, while sarcopenia caused by disease-specific conditions is referred to as secondary sarcopenia. On the other hand, the liver-muscle axis has been attracting attention in recent years, and it has become clear that the liver and the skeletal muscles interact with each other. In particular, patients with cirrhosis are prone to secondary sarcopenia due to protein-energy malnutrition, which is a characteristic pathophysiology of the disease, suggesting the importance of the organ-organ network. In this review, we would like to outline the latest findings in this field, with a focus on body composition in liver diseases such as liver cirrhosis, fatty liver disease, alcoholic liver disease, and hepatocellular carcinoma.

Viral Liver Disease and Intestinal Gut–Liver Axis

The intestinal microbiota is closely related to liver diseases via the intestinal barrier and bile secretion to the gut. Impairment of the barrier can translocate microbes or their components to the liver where they can contribute to liver damage and fibrosis. The components of the barrier are discussed in this review along with the other elements of the so-called gut–liver axis. This bidirectional relation has been widely studied in alcoholic and non-alcoholic liver disease. However, the involvement of microbiota in the pathogenesis and treatment of viral liver diseases have not been extensively studied, and controversial data have been published. Therefore, we reviewed data regarding the integrity and function of the intestinal barrier and the changes of the intestinal microbioma that contribute to progression of Hepatitis B (HBV) and Hepatitis C (HCV) infection. Their consequences, such as cirrhosis and hepatic encephalopathy, were also discussed in connection with therapeutic interventions such as the effects of antiviral eradication and the use of probiotics that may influence the outcome of liver disease. Profound alterations of the microbioma with significant reduction in microbial diversity and changes in the abundance of both beneficial and pathogenic bacteria were found.

The gut-liver axis in hepatobiliary diseases

Recent advances in the analysis of intestinal bacteria have led to reports of variations in intestinal bacterial levels among hepatobiliary diseases. The mechanisms behind the changes in intestinal bacteria in various hepatobiliary diseases include the abnormal composition of intestinal bacteria, weakening of the intestinal barrier, and bacterial translocation outside the intestinal tract, along with their metabolites, but many aspects remain unresolved. Further research employing clinical studies and animal models is expected to clarify the direct relationship between intestinal bacteria and hepatobiliary diseases and to validate the utility of intestinal bacteria as a diagnostic biomarker and potential therapeutic target. This review summarizes the involvement of the microbiota in the pathogenesis of hepatobiliary diseases via the gut-liver axis.

Faecal (or intestinal) microbiota transplant: a tool for repairing the gut microbiome

Faecal/intestinal microbiota transplant (FMT/IMT) is an efficacious treatment option for recurrent Clostridioides difficile infection, which has prompted substantial interest in FMT's potential role in the management of a much broader range of diseases associated with the gut microbiome. Despite its promise, the success rates of FMT in these other settings have been variable. This review critically evaluates the current evidence on the impact of clinical, biological, and procedural factors upon the therapeutic efficacy of FMT, and identifies areas that remain nebulous. Due to some of these factors, the optimal therapeutic approach remains unclear; for example, the preferred timing of FMT administration in a heavily antibiotic-exposed hematopoietic cell transplant recipient is not standardized, with arguments that can be made in alternate directions. We explore how these factors may impact upon more informed selection of donors, potential matching of donors to recipients, and aspects of clinical care of FMT recipients. This includes consideration of how gut microbiome composition and functionality may strategically inform donor selection criteria. Furthermore, we review how the most productive advances within the FMT space are those where clinical and translational outcomes are assessed together, and where this model has been used productively in recent years to better understand the contribution of the gut microbiome to human disease, and start the process toward development of more targeted microbiome therapeutics.

Gut microbiome therapy: fecal microbiota transplantation vs live biotherapeutic products

The human intestine hosts a complex ecosystem of various microorganisms, collectively known as the gut microbiome, which significantly impacts human health. Disruptions in the gut microbiome are linked to various disorders, including gastrointestinal diseases, such as Clostridioides difficile infection and inflammatory bowel disease, as well as metabolic, neurological, oncologic conditions. Fecal microbiota transplantation (FMT) and live biotherapeutic products (LBPs) have emerged as prospective therapeutic procedures to restore microbial and metabolic balance in the gut. This review assesses the latest advancements, challenges, and therapeutic efficacy of FMT and LBPs, highlighting the need for standardization, safety, and long-term evaluation to optimize their clinical application.

The Interaction of Microbiome and Pancreas in Acute Pancreatitis

Acute pancreatitis (AP) is a common acute abdomen disease characterized by the pathological activation of digestive enzymes and the self-digestion of pancreatic acinar cells. Secondary infection and sepsis are independent prognosticators for AP progression and increased mortality. Accumulating anatomical and epidemiological evidence suggests that the dysbiosis of gut microbiota affects the etiology and severity of AP through intestinal barrier disruption, local or systemic inflammatory response, bacterial translocation, and the regulatory role of microbial metabolites in AP patients and animal models. Recent studies discussing the interactions between gut microbiota and the pancreas have opened new scopes for AP, and new therapeutic interventions that target the bacteria community have received substantial attention. This review concentrates on the alterations of gut microbiota and its roles in modulating gut-pancreas axis in AP. The potential therapies of targeting microbes as well as the major challenges of applying those interventions are explored. We expect to understand the roles of microbes in AP diagnosis and treatment.

A Comprehensive Overview of the Past, Current, and Future Randomized Controlled Trials in Hepatic Encephalopathy

Background: Hepatic encephalopathy (HE) caused by cirrhosis has severe consequences on an individual's lifespan, leading to long-term liver complications and potentially life-threatening outcomes. Despite recent interest in this condition, the effectiveness of secondary prophylaxis involving rixafimin, lactulose, or L-ornithine L-aspartate (LOLA) may be hindered by the unique microbial profiles each patient possesses. Methods: Thus, in this manuscript, we aimed to search, identify, and gather all randomized controlled trials (RCTs) published between 2000-2023 (November) in four major academic databases such as PubMed, ISI Web of Science, Scopus, and ScienceDirect by using a controlled terminology and web strings that reunite six main keywords. We complementarily retrieved data on the ongoing RCTs. Results: Regardless of the relatively high number of results displayed (n = 75), 46.66% (n = 35) were initially deemed eligible after the first evaluation phase after removing duplicates, n = 40 (53.34%). At the second assessment stage, we eliminated 11.42% (n = 4) studies, of which n = 22 finally met the eligibility criteria to be included in the main body of the manuscript. In terms of RCTs, otherwise found in distinct stages of development, n = 3 target FMT and n = 1 probiotics. Conclusions: Although we benefit from the necessary information and technology to design novel strategies for microbiota, only probiotics and synbiotics have been extensively studied in the last decade compared to FMT.

The role of faecal microbiota transplantation in chronic noncommunicable disorders

The gut microbiome plays a key role in influencing several pathways and functions involved in human health, including metabolism, protection against infection, and immune regulation. Perturbation of the gut microbiome is recognised as a pathogenic factor in several gastrointestinal and extraintestinal disorders, and is increasingly considered as a therapeutic target in these conditions. Faecal microbiota transplantation (FMT) is the transfer of the microbiota from healthy screened stool donors into the gut of affected patients, and is a well-established and highly effective treatment for recurrent Clostridioides difficile infection. Despite the mechanisms of efficacy of FMT not being fully understood, it has been investigated in several chronic noncommunicable disorders, with variable results. This review aims to give an overview of mechanisms of efficacy of FMT in chronic noncommunicable disorders, and to paint the current landscape of its investigation in these medical conditions, including inflammatory bowel disease (IBD), chronic liver disorders, and also extraintestinal autoimmune conditions.

Alterations in gut virome are associated with cognitive function and minimal hepatic encephalopathy cross-sectionally and longitudinally in cirrhosis

Cognitive dysfunction due to minimal hepatic encephalopathy (MHE) adversely impacts patients with cirrhosis and more precise therapies are needed. Gut-brain axis changes are therapeutic targets, but prior studies have largely focused on bacterial changes. Our aim was to determine linkages between individual cognitive testing results and bacteria with the virome using a cross-sectional and longitudinal approach. We included cross-sectional (n = 138) and longitudinal analyses (n = 36) of patients with cirrhosis tested using three cognitive modalities, which were psychometric hepatic encephalopathy score (PHES), inhibitory control test (ICT), Stroop, and all three. Stool metagenomics with virome and bacteriome were analyzed studied cross-sectionally and in a subset followed for development/reversal of MHE repeated at 6 months (longitudinally only using PHES). Cross-sectional: We found no significant changes in α/β diversity in viruses or bacteria regardless of cognitive testing. Cognitively impaired patients were more likely to have higher relative abundance of bacteriophages linked with Streptococcus, Faecalibacterium, and Lactobacillus, which were distinct based on modality. These were also linked with cognition on correlation networks. Longitudinally, 27 patients remained stable while 9 changed their MHE status. Similar changes in phages that are linked with Streptococcus, Faecalibacterium, and Lactobacillus were seen. These phages can influence ammonia, lactate, and short-chain fatty acid generation, which are neuro-active. In conclusion, we found linkages between bacteriophages and cognitive function likely due to impact on bacteria that produce neuroactive metabolites cross-sectionally and longitudinally. These findings could help explore bacteriophages as options to influence treatment for MHE in cirrhosis.

Microbiome and Genetic Factors in the Pathogenesis of Liver Diseases

Our genetic background has not changed over the past century, but chronic diseases are on the rise globally. In addition to the genetic component, among the critical factors for many diseases are inhabitants of our intestines (gut microbiota) as a crucial environmental factor. Dysbiosis has been described in liver diseases with different etiologies like non-alcoholic fatty liver disease (NAFLD), alcohol-related liver disease (ALD), viral hepatitis, autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC), cirrhosis, hepatocellular carcinoma (HCC). On the other hand, new technologies have increased our understanding of liver disease genetics and treatment options. Genome-wide association studies (GWAS) identify unknown genetic risk factors, positional cloning of unknown genes associated with different diseases, gene tests for single nucleotide variations (SNVs), and next-generation sequencing (NGS) of selected genes or the complete genome. NGS also allowed studying the microbiome and its role in various liver diseases has begun. These genes have proven their effect on microbiome composition in host genome–microbiome association studies. We focus on altering the intestinal microbiota, and supplementing some bacterial metabolites could be considered a potential therapeutic strategy. The literature data promote probiotics/synbiotics role in reducing proinflammatory cytokines such as TNF-α and the interleukins (IL-1, IL-6, IL-8), therefore improving transaminase levels, hepatic steatosis, and NAFLD activity score. However, even though microbial therapy appears to be risk-free, evaluating side effects related to probiotics or synbiotics is imperative. In addition, safety profiles for long-term usage should be researched. Thus, this review focuses on the human microbiome and liver diseases, recent GWASs on liver disease, the gut-liver axis, and the associations with the microbiome and microbiome during/after liver disease therapy.

Bifidobacteria metabolize lactulose to optimize gut metabolites and prevent systemic infection in patients with liver disease

Progression of chronic liver disease is precipitated by hepatocyte loss, inflammation and fibrosis. This process results in the loss of critical hepatic functions, increasing morbidity and the risk of infection. Medical interventions that treat complications of hepatic failure, including antibiotic administration for systemic infections and lactulose treatment for hepatic encephalopathy, can impact gut microbiome composition and metabolite production. Here, using shotgun metagenomic sequencing and targeted metabolomic analyses on 847 faecal samples from 262 patients with acute or chronic liver disease, we demonstrate that patients hospitalized for liver disease have reduced microbiome diversity and a paucity of bioactive metabolites, including short-chain fatty acids and bile acid derivatives, that impact immune defences and epithelial barrier integrity. We find that patients treated with the orally administered but non-absorbable disaccharide lactulose have increased densities of intestinal bifidobacteria and reduced incidence of systemic infections and mortality. Bifidobacteria metabolize lactulose, produce high concentrations of acetate and acidify the gut lumen in humans and mice, which, in combination, can reduce the growth of antibiotic-resistant bacteria such as vancomycin-resistant Enterococcus faecium in vitro. Our studies suggest that lactulose and bifidobacteria serve as a synbiotic to reduce rates of infection in patients with severe liver disease.

Therapeutic modulation of the liver immune microenvironment

Inflammation is a hallmark of progressive liver diseases such as chronic viral or immune-mediated hepatitis, alcohol-associated liver disease, and NAFLD. Preclinical and clinical studies have provided robust evidence that cytokines and related cellular stress sensors in innate and adaptive immunity orchestrate hepatic disease processes. Unresolved inflammation and liver injury result in hepatic scarring, fibrosis, and cirrhosis, which may culminate in HCC. Liver diseases are accompanied by gut dysbiosis and a bloom of pathobionts, fueling hepatic inflammation. Anti-inflammatory strategies are extensively used to treat human immune-mediated conditions beyond the liver, while evidence for immunomodulatory therapies and cell therapy-based strategies in liver diseases is only emerging. The development and establishment of novel immunomodulatory therapies for chronic liver diseases has been dampened by several clinical challenges, such as invasive monitoring of therapeutic efficacy with liver biopsy in clinical trials and risk of DILI in several studies. Such aspects prevented advancements of novel medical therapies for chronic inflammatory liver diseases. New concepts modulating the liver immune environment are studied and eagerly awaited to improve the management of chronic liver diseases in the future.

Novel Therapeutic Approaches in Treatment of Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF), a clinical syndrome that can develop at any stage in the progression of cirrhotic liver disease, is characterized by an acute decompensation in liver function with associated multiorgan failure and high short-term mortality. Current evidence points to ACLF being reversible, particularly in those at the lower end of the severity spectrum. However, there are no specific treatments for ACLF, and overall outcomes remain poor. Expedited liver transplantation as a treatment option is limited by organ shortage and a lack of priority allocation for this indication. Other options are therefore urgently needed, and our improved understanding of the condition has led to significant efforts to develop novel therapies. In conclusion, this review aims to summarize the current understanding of the pathophysiological processes involved in the onset, progression, and recovery of ACLF and discuss novel therapies under development.

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

The trillions of microorganisms in the human intestine are important regulators of health, and disruptions in the gut microbial communities can cause disease. The gut, liver and immune system have a symbiotic relationship with these microorganisms. Environmental factors, such as high-fat diets and alcohol consumption, can disrupt and alter microbial communities. This dysbiosis can lead to dysfunction of the intestinal barrier, translocation of microbial components to the liver and development or progression of liver disease. Changes in metabolites produced by gut microorganisms can also contribute to liver disease. In this Review, we discuss the importance of the gut microbiota in maintenance of health and the alterations in microbial mediators that contribute to liver disease. We present strategies for modulation of the intestinal microbiota and/or their metabolites as potential treatments for liver disease.

Fecal Microbiota Transplantation in Liver Cirrhosis

The human gastrointestinal tract houses a diverse array of probiotic and pathogenic bacteria and any alterations in this microbial composition can exert a significant influence on an individual's well-being. It is well-established that imbalances in the gut microbiota play a pivotal role in the development of liver diseases. In light of this, a new adjuvant therapy for liver diseases could be regulating the intestinal microbiota. Through fecal microbiota transplantation, patients whose microbiomes are compromised are treated with stool from healthy donors in an attempt to restore a normal microbiome and alleviate their symptoms. A review of cross-sectional studies and case reports suggests that fecal microbiota transplants may offer effective treatment for chronic liver diseases. Adding to the potential of this emerging therapy, recent research has indicated that fecal microbiota transplantation holds promise as a therapeutic approach specifically for liver cirrhosis. By introducing a diverse range of beneficial microorganisms into the gut, this innovative treatment aims to address the microbial imbalances often observed in cirrhotic patients. While further validation is still required, these preliminary findings highlight the potential impact of fecal microbiota transplantation as a novel and targeted method for managing liver cirrhosis. We aimed to summarize the current state of understanding regarding this procedure, as a new therapeutic method for liver cirrhosis, as well as to explain its clinical application and future potential.

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.

Hepatic encephalophathy: management and diagnostic therapeutic assistance path of Ligurian Local Health Company 3 (ASL3)

Hepatic encephalophathy (HE) is a neuropsychiatric syndrome with a prevalence in the cirrhotic population ranging from 20 to 80%. HE is a cause of inappropriate hospitalization, caregiver burdening and increased social costs. There is need to create dedicated care pathways to better manage patients and support family caregivers. The data used for the preparation of this diagnostic therapeutic assistance path (DTAP) are based on a detailed analysis of the scientific literature published before June 30, 2022 (PubMed, Web of Science, Scopus, Google Scholar). Furthermore, in the process of developing this work, we consulted in particular the guidelines/ position papers of International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN), Italian Association for the Study of the Liver (AISF), European Association for the Study of the Liver (EASL), American Association for the Study of Liver Diseases (AASLD), Italian Society on Alcohol (Società Italiana di Alcologia [SIA]) and other relevant papers. DTAP was created based on the most recent recommendations of the international scientific literature. The present DTAP highlight the need for a multidisciplinary activity integrated with territorial medicine in close connection with caregivers. This guarantees improved therapeutic adherence, hospital readmission reduction, improved quality of life for patients and caregivers and a significant reduction in costs.

The Role of Gut Microbiome-Derived Short-Chain Fatty Acid Butyrate in Hepatobiliary Diseases

The short-chain fatty acid butyrate, produced from fermentable carbohydrates by gut microbiota in the colon, has multiple beneficial effects on human health. At the intestinal level, butyrate regulates metabolism, helps in the transepithelial transport of fluids, inhibits inflammation, and induces the epithelial defense barrier. The liver receives a large amount of short-chain fatty acids via the blood flowing from the gut via the portal vein. Butyrate helps prevent nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, inflammation, cancer, and liver injuries. It ameliorates metabolic diseases, including insulin resistance and obesity, and plays a direct role in preventing fatty liver diseases. Butyrate has different mechanisms of action, including strong regulatory effects on the expression of many genes by inhibiting the histone deacetylases and modulating cellular metabolism. The present review highlights the wide range of beneficial therapeutic and unfavorable adverse effects of butyrate, with a high potential for clinically important uses in several liver diseases.

Is there a role for microbiome-based approach in common variable immunodeficiency?

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by low levels of serum immunoglobulins and increased susceptibility to infections, autoimmune disorders and cancer. CVID embraces a plethora of heterogeneous manifestations linked to complex immune dysregulation. While CVID is thought to be due to genetic defects, the exact cause of this immune disorder is unknown in the large majority of cases. Compelling evidences support a linkage between the gut microbiome and the CVID pathogenesis, therefore a potential for microbiome-based treatments to be a therapeutic pathway for this disorder. Here we discuss the potential of treating CVID patients by developing a gut microbiome-based personalized approach, including diet, prebiotics, probiotics, postbiotics and fecal microbiota transplantation. We also highlight the need for a better understanding of microbiota-host interactions in CVID patients to prime the development of improved preventive strategies and specific therapeutic targets.

CE: Current and Emerging Applications of Fecal Microbiota Transplantation

ABSTRACT

Fecal microbiota transplantation (FMT) is a life-changing treatment for people with recurrent Clostridioides difficile infection (rCDI). Frequently acquired in the hospital, CDI can cause serious gastrointestinal symptoms, including persistent watery diarrhea, abdominal pain, and severe dehydration. Antibiotics, the primary treatment, can unfortunately disrupt the gut microbiome and lead to antimicrobial resistance. FMT involves introducing stool from a healthy donor into the affected recipient to strengthen their compromised microbiome. Individuals receiving this treatment have reported remarkable improvement in clinical outcomes and quality of life. In addition to a discussion of rCDI within the context of the gastrointestinal microbiome, this article provides an overview of the FMT procedure, discusses nursing management of individuals undergoing FMT, and highlights emerging applications beyond rCDI. A case scenario is also provided to illustrate a typical trajectory for a patient undergoing FMT.

p-Cresol Sulfate Is a Sensitive Urinary Marker of Fecal Microbiota Transplantation and Antibiotics Treatments in Human Patients and Mouse Models

Fecal microbiota transplantation (FMT) has emerged as a highly effective therapy for recurrent Clostridioides difficile infection (rCDI) and also a potential therapy for other diseases associated with dysbiotic gut microbiota. Monitoring metabolic changes in biofluids and excreta is a noninvasive approach to identify the biomarkers of microbial recolonization and to understand the metabolic influences of FMT on the host. In this study, the pre-FMT and post FMT urine samples from 11 rCDI patients were compared through metabolomic analyses for FMT-induced metabolic changes. The results showed that p-cresol sulfate in urine, a microbial metabolite of tyrosine, was rapidly elevated by FMT and much more responsive than other microbial metabolites of aromatic amino acids (AAAs). Because patients were treated with vancomycin prior to FMT, the influence of vancomycin on the microbial metabolism of AAAs was examined in a mouse feeding trial, in which the decreases in p-cresol sulfate, phenylacetylglycine, and indoxyl sulfate in urine were accompanied with significant increases in their AAA precursors in feces. The inhibitory effects of antibiotics and the recovering effects of FMT on the microbial metabolism of AAAs were further validated in a mouse model of FMT. Overall, urinary p-cresol sulfate may function as a sensitive and convenient therapeutic indicator on the effectiveness of antibiotics and FMT for the desired manipulation of gut microbiota in human patients.