Long-term Outcomes of Fecal Microbiota Transplantation in Patients With Cirrhosis

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.

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.

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.

Gut microbiota in MAFLD: therapeutic and diagnostic implications

Metabolic dysfunction-associated fatty liver disease (MAFLD), formerly known as nonalcoholic fatty liver disease, is becoming a significant contributor to chronic liver disease globally, surpassing other etiologies, such as viral hepatitis. Prevention and early treatment strategies to curb its growing prevalence are urgently required. Recent evidence suggests that targeting the gut microbiota may help treat and alleviate disease progression in patients with MAFLD. This review aims to explore the complex relationship between MAFLD and the gut microbiota in relation to disease pathogenesis. Additionally, it delves into the therapeutic strategies targeting the gut microbiota, such as diet, exercise, antibiotics, probiotics, synbiotics, glucagon-like peptide-1 receptor agonists, and fecal microbiota transplantation, and discusses novel biomarkers, such as microbiota-derived testing and liquid biopsy, for their diagnostic and staging potential. Overall, the review emphasizes the urgent need for preventive and therapeutic strategies to address the devastating consequences of MAFLD at both individual and societal levels and recognizes that further exploration of the gut microbiota may open avenues for managing MAFLD effectively in the future.

Fecal microbiota transplantation for treatment of non-alcoholic fatty liver disease: Mechanism, clinical evidence, and prospect

The population of non-alcoholic fatty liver disease (NAFLD) patients along with relevant advanced liver disease is projected to continue growing, because currently no medications are approved for treatment. Fecal microbiota transplantation (FMT) is believed a novel and promising therapeutic approach based on the concept of the gut-liver axis in liver disease. There has been an increase in the number of pre-clinical and clinical studies evaluating FMT in NAFLD treatment, however, existing findings diverge on its effects. Herein, we briefly summarized the mechanism of FMT for NAFLD treatment, reviewed randomized controlled trials for evaluating its efficacy in NAFLD, and proposed the prospect of future trials on FMT.

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.

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.

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.

Getting off tract: contributions of intraorgan microbiota to cancer in extraintestinal organs

The gastrointestinal ecosystem has received the most attention when examining the contributions of the human microbiome to health and disease. This concentration of effort is logical due to the overwhelming abundance of microbes in the gut coupled with the relative ease of sampling compared with other organs. However, the intestines are intimately connected to multiple extraintestinal organs, providing an opportunity for homeostatic microbial colonisation and pathogenesis in organs traditionally thought to be sterile or only transiently harbouring microbiota. These habitats are challenging to sample, and their low microbial biomass among large amounts of host tissue can make study challenging. Nevertheless, recent findings have shown that many extraintestinal organs that are intimately linked to the gut harbour stable microbiomes, which are colonised from the gut in selective manners and have highlighted not just the influence of the bacteriome but that of the mycobiome and virome on oncogenesis and health.

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.

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.

Impact of liver fibrosis on the relative abundance of a urease-positive Streptococcus salivarius group from saliva in patients with chronic liver disease

AIM

We performed genomic analysis to study the relative abundance of a urease-positive Streptococcus salivarius group isolated from the saliva of patients with chronic liver disease.

METHODS

Male and female patients with chronic liver disease aged over 20 years were included. First, we assessed the frequency and type of the S. salivarius group isolated from oral saliva using molecular biology techniques based on 16S rRNA and dephospho-coenzyme A kinase gene sequencing. Next, we assessed the correlation between the urease positivity rate in the S. salivarius group isolated from oral saliva and liver fibrosis based on chronic liver disease. Urease-positive strains were identified by the urease test using urea broth (Difco, Franklin Lakes, NJ, USA). Liver fibrosis was evaluated by the liver stiffness measurement value based on magnetic resonance elastography.

RESULTS

A total of 45 patients identified using the multiplex polymerase chain reaction for the 16S rRNA gene were tested using the multiplex polymerase chain reaction for the dephospho-coenzyme A kinase gene. Confirming the strains detected in each of the 45 patients, urease-positive S. salivarius was detected in 28 patients (62%), urease-negative S. salivarius in 25 patients (56%), and urease-positive Streptococcus vestibularis in 12 patients (27%). There was no patient with urease-negative S. vestibularis. The urease-positive rate of the S. salivarius group in the cirrhosis and non-cirrhosis groups were 82.2% and 39.2%, respectively. The liver cirrhosis group had a higher urease positivity rate than the non-cirrhotic group (p < 0.001).

CONCLUSIONS

Liver fibrosis influences the frequency of a urease-positive S. salivarius group isolated from oral saliva.

A meta-analysis of microbiome therapies for hepatic encephalopathy

Microbiome therapies may be reported to be effective in hepatic encephalopathy (HE). We thus did a meta-analysis of randomized controlled trials to assess the effect of microbiome therapies for HE. We systematically searched PubMed, Web of Science, EMBASE, and Cochrane Library for randomized controlled trials that compared the different treatments for HE including probiotics, symbiotics, and fecal microbiota transplant (FMT). Meta-analysis was performed to calculate pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs). Twenty-one studies met our inclusion criteria (N = 1746 participants). Probiotics, synbiotics and FMT significantly reversed minimal HE (MHE) (OR: 0.41, 95% CI: 0.19-0.90, P = 0.03), reduced overt HE (OHE) development (OR, 0.41; 95% CI: 0.28-0.61 P < 0.00001)and the frequency of serious adverse events(SAEs) (OR:0.14, 95% CI: 0.04-0.47, P = 0.001), meanwhile decreased ammonia levels (WMD: -9.26, 95% CI: -16.92 to -1.61; P = 0.02), NCT level (MD = -4.41, 95% CI: -0.87 to -0.22, P = 0.04) and hospitalization rates (OR, 0.38; 95% CI: 0.19-0.79, P = 0.009) compared with placebo/no treatment. Finally, we conclude that microbiome therapies were more effective in improving MHE and preventing progression to OHE, reducing the frequency of SAEs, and decreasing ammonia levels, NCT level, and hospitalization rates when compared to placebo/no treatment.

Therapeutic possibilities of gut microbiota modulation in acute decompensation of liver cirrhosis

The formation of liver cirrhosis (LC) is an unfavorable event in the natural history of chronic liver diseases and with the development of portal hypertension and/or impaired liver function can cause a fatal outcome. Decompensation of LC is considered the most important stratification variable for the risk of death. It is currently postulated that decompensation of LC occurs through an acute (including acute-on-chronic liver failure) and non-acute pathway. Acute decompensation of LC is accompanied by the development of life-threatening complications, characterized by an unfavorable prognosis and high mortality. Progress in understanding the underlying molecular mechanisms has led to the search for new interventions, drugs, and biological substances that can affect key links in the pathogenesis of acute decompensation in LC, for example the impaired gut-liver axis and associated systemic inflammation. Given that particular alterations in the composition and function of gut microbiota play a crucial role here, the study of the therapeutic possibilities of its modulation has emerged as one of the top concerns in modern hepatology. This review summarized the investigations that describe the theoretical foundations and therapeutic potential of gut microbiota modulation in acute decompensation of LC. Despite the encouraging preliminary data, the majority of the suggested strategies have only been tested in animal models or in preliminary clinical trials; additional multicenter randomized controlled trials must demonstrate their efficacy in larger patient populations.

Current vision on diagnosis and comprehensive care in hepatic encephalopathy

The first clinical guidelines on hepatic encephalopathy were published in 2009. Almost 14 years since that first publication, numerous advances in the field of diagnosis, treatment, and special condition care have been made. Therefore, as an initiative of the Asociación Mexicana de Gastroenterología A.C., we present a current view of those aspects. The manuscript described herein was formulated by 24 experts that participated in six working groups, analyzing, discussing, and summarizing the following topics: Definition of hepatic encephalopathy; recommended classifications; epidemiologic panorama, worldwide and in Mexico; diagnostic tools; conditions that merit a differential diagnosis; treatment; and primary and secondary prophylaxis. Likewise, these guidelines emphasize the management of certain special conditions, such as hepatic encephalopathy in acute liver failure and acute-on-chronic liver failure, as well as specific care in patients with hepatic encephalopathy, such as the use of medications and types of sedation, describing those that are permitted or recommended, and those that are not.

Faecal Microbiota Transplantation, Paving the Way to Treat Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is currently the most prevalent cause of chronic liver disease (CLD). Currently, the only therapeutic recommendation available is a lifestyle change. However, adherence to this approach is often difficult to guarantee. Alteration of the microbiota and an increase in intestinal permeability seem to be key in the development and progression of NAFLD. Therefore, the manipulation of microbiota seems to provide a promising therapeutic strategy. One way to do so is through faecal microbiota transplantation (FMT). Here, we summarize the key aspects of FMT, detail its current indications and highlight the most recent advances in NAFLD.

Gut microbiome-brain-cirrhosis axis

Cirrhosis is characterized by inflammation, degeneration, and fibrosis of liver tissue. Along with being the most common cause of liver failure and liver transplant, cirrhosis is a significant risk factor for several neuropsychiatric conditions. The most common of these is HE, which is characterized by cognitive and ataxic symptoms, resulting from the buildup of metabolic toxins with liver failure. However, cirrhosis patients also show a significantly increased risk for neurodegenerative diseases such as Alzheimer and Parkinson diseases, and for mood disorders such as anxiety and depression. In recent years, more attention has been played to communication between the ways the gut and liver communicate with each other and with the central nervous system, and the way these organs influence each other's function. This bidirectional communication has come to be known as the gut-liver-brain axis. The gut microbiome has emerged as a key mechanism affecting gut-liver, gut-brain, and brain-liver communication. Clinical studies and animal models have demonstrated the significant patterns of gut dysbiosis when cirrhosis is present, both with or without concomitant alcohol use disorder, and have provided compelling evidence that this dysbiosis also influences the cognitive and mood-related behaviors. In this review, we have summarized the pathophysiological and cognitive effects associated with cirrhosis, links to cirrhosis-associated disruption of the gut microbiome, and the current evidence from clinical and preclinical studies for the modulation of the gut microbiome as a treatment for cirrhosis and associated neuropsychiatric conditions.

Hepatic encephalopathy - recent advances in treatment and diagnosis

INTRODUCTION

Hepatic encephalopathy (HE) is a peculiar kind of brain dysfunction typical of liver cirrhosis characterized by nonspecific neurological and psychiatric manifestations. HE ranges from minimal hepatic encephalopathy (MHE) to the most severe form characterized by alteration of consciousness or coma (overt HE, OHE). Once the diagnosis of OHE is made, every effort to identify and correct the precipitating cause is essential for the resolution of symptoms. Clinical studies that assessed the prevalence and incidence of any type of HE (MHE and OHE) in patients affected by cirrhosis were included in this review. No language, publication date, or publication status restrictions were imposed. The studies were identified by searching electronic databases (PubMed and SCOPUS).

AREAS COVERED

The most widely empirical pharmacological approach consists of non-absorbable antibiotics (rifaximin) and non-absorbable disaccharides (lactulose, lactitol per os and per enemas). Other agents (including branched-chain amino acids, probiotics, other antibiotics, or intravenous L-ornithine L-aspartate) are available, but the evidence supporting their efficacy remains under debate.

EXPERT OPINION

Gray areas and future needs remain the therapeutic approach to MHE and issues in the design of therapeutic studies for HE which have been extensively discussed in this review.

Fecal microbiota transplantation compared with prednisolone in severe alcoholic hepatitis patients: a randomized trial

BACKGROUND

Severe alcoholic hepatitis (SAH) has high 90-day mortality. Prednisolone therapy has shown modest survival benefits over placebo at 28 but not 90 days. Fecal microbial transplantation (FMT) has shown promise in these patients. We compared the efficacy and safety of the two therapies in SAH patients.

METHODS

Steroid eligible SAH patients were randomized in an open-label study to prednisolone (n = 60) 40 mg/day for 28 days (assessed at day-7 for continuation) or healthy donor FMT (n = 60) through naso-duodenal tube, daily for seven days. Primary outcome of study was day-90 survival.

RESULTS

Patients in prednisolone and FMT arms were comparable at baseline (discriminant function score 65 ± 16.2 and 68 ± 14, MELD score 17.1 and 16.5, respectively). Of 120 patients, 112 [prednisolone-57; FMT-55] completed trial. As per intention-to-treat analysis, 90-day survival was achieved by 56.6% (34/60) patients in prednisolone and 75% (45/60) in FMT group (p = 0.044, FMT HR = 0.528, 95%CI 0.279-0.998). Secondary outcome of 28-day survival [78.33% (47/60) and 88.33% (53/60) (p = 0.243, FMT HR = 0.535, 95%CI 0.213-1.34)] with comparable severity scores over time between both arms. Infections accounted for 11 (19.3%) and 2 (3.6%) deaths in prednisolone and FMT groups, respectively (p = 0.01). Path-tracing showed a slow establishment of microbiota and alpha diversity (Shannon index) improvement by day-28 (p = 0.029). FMT resulted in 23 new taxa by day-28, reduction from baseline in pathogenic taxa [Campylobacter (19-fold, p = 0.035), anaerobes (Parcubacteria, Weisella and Leuconostocaceae)], and increase of Alphaproteobacteria [~ sevenfold, p = 0.047] and Thaumarcheota (known ammonia oxidizer, p = 0.06). Lachnospiraceae (p = 0.008), Prevotella and Viellonella communities in gut favored survival (p < 0.05).

CONCLUSION

In severe alcoholic hepatitis, FMT is safe and improves 90-day survival and reduces infections by favorably modulating microbial communities. It can be a useful alternative to prednisolone therapy.

Role of gut microbiota in the pathogenesis and therapeutics of minimal hepatic encephalopathy via the gut-liver-brain axis

Minimal hepatic encephalopathy (MHE) is a frequent neurological and psychiatric complication of liver cirrhosis. The precise pathogenesis of MHE is complicated and has yet to be fully elucidated. Studies in cirrhotic patients and experimental animals with MHE have indicated that gut microbiota dysbiosis induces systemic inflammation, hyperammonemia, and endotoxemia, subsequently leading to neuroinflammation in the brain via the gut-liver-brain axis. Related mechanisms initiated by gut microbiota dysbiosis have significant roles in MHE pathogenesis. The currently available therapeutic strategies for MHE in clinical practice, including lactulose, rifaximin, probiotics, synbiotics, and fecal microbiota transplantation, exert their effects mainly by modulating gut microbiota dysbiosis. Microbiome therapies for MHE have shown promised efficacy and safety; however, several controversies and challenges regarding their clinical use deserve to be intensively discussed. We have summarized the latest research findings concerning the roles of gut microbiota dysbiosis in the pathogenesis of MHE via the gut-liver-brain axis as well as the potential mechanisms by which microbiome therapies regulate gut microbiota dysbiosis in MHE patients.

Current approaches to hepatic encephalopathy

Hepatic encephalopathy (HE) is a brain dysfunction caused by liver insufficiency and/or portosystemic shunts. Between 30%-40% of patients with cirrhosis will present overt HE during their lifetime. While the pathophysiology of HE is not entirely understood, three critical factors have been identified: hyperammonaemia, systemic inflammation and oxidative stress by glutaminase gene alterations. Minimal HE is defined by the presence of signs of cognitive abnormalities in a patient without asterixis or disorientation; it can only be diagnosed with neuropsychological or psychometric tests. The diagnosis of overt HE is based on clinical examination with clinical scales. Currently, only overt HE should be routinely treated. The aims of treatment in an acute episode should be to improve the mental status, identify and treat the precipitating factor, reduce duration and limit consequences. Treatment strategies are targeted at reducing ammonia production and/or increasing its elimination. Even though minimal HE has negative effects on the patient's quality of life and effects on prognosis, indications for treatment are still controversial. There are still many unanswered questions regarding the pathophysiology and management of HE. We should also endeavor to develop more accurate and objective diagnostic methods for overt HE that would permit early detection and help improve outcomes on quality of life and economic burden.

Comprehensive bibliometric and visualized analysis of research on fecal microbial transplantation published from 2000 to 2021

Background

Fecal microbial transplantation has emerged in recent years as a method of treating disease by rebuilding the intestinal flora. However, few bibliometric analyses have systematically studied this area of research. We aimed to use bibliometric analysis to visualize trends and topical research in fecal microbial transplantation to help provide insight into future trends in clinical and basic research.

Materials and methods

Articles and reviews related to fecal microbial transplantation were collected from the Web of Science Core Collection. Significant information associated with this field was visually analyzed by using Biblioshiny and CtieSpace software.

Results

A total of 3144 articles and overviews were included. The number of publications related to fecal microbial transplantation significantly increased yearly. These publications mainly came from 100 countries, led by the US and China, and 521 institutions. The most prolific and influential author is KHORUTS A. The main disciplines and application fields of fecal microbial transplantation included molecular /biology/immunology and medicine/clinical medicine, and the research foundation of fecal microbial transplantation was molecular /biology/genetics and health/nursing/medicine. An alluvial flow visualization showed several landmark articles. New developments were identified in terms of reference and keyword citation bursts. Data analysis showed that different FMT preparation and delivery methods gradually appeared as research hotspots. The main research keywords in the last 3 years were chain fatty acids, Akkermansia muciniphila, and insulin sensitivity, other keywords were current and developing research fields.

Conclusion

Research on fecal microbial transplantation is flourishing and many new applications of fecal microbial transplantation are emerging. Microbial metabolites such as short-chain fatty acids and the microbiota–gut–brain axis have become the focus of current research and are future research trends.

EASL Clinical Practice Guidelines on the management of hepatic encephalopathy

The EASL Clinical Practice Guidelines (CPGs) on the management of hepatic encephalopathy (HE) present evidence-based answers to a set of relevant questions (where possible, formulated in PICO [patient/population, intervention, comparison and outcomes] format) on the definition, diagnosis, differential diagnosis and treatment of HE. The document does not cover the pathophysiology of HE and does not cover all available treatment options. The methods through which it was developed and any information relevant to its interpretation are also provided.

The gut-liver axis in immune remodeling of hepatic cirrhosis

In healthy settings, the gut-liver axis allows host-microbiota communications and mediates immune homeostasis through bidirectional regulation. Meanwhile, in diseases, gut dysbiosis, combined with an impaired intestinal barrier, introduces pathogens and their toxic metabolites into the system, causing massive immune alternations in the liver and other extrahepatic organs. Accumulating evidence suggests that these immune changes are associated with the progression of many liver diseases, especially hepatic cirrhosis. Pathogen-associated molecular patterns that originated from gut microbes directly stimulate hepatocytes and liver immune cells through different pattern recognition receptors, a process further facilitated by damage-associated molecular patterns released from injured hepatocytes. Hepatic stellate cells, along with other immune cells, contribute to this proinflammatory and profibrogenic transformation. Moreover, cirrhosis-associated immune dysfunction, an imbalanced immune status characterized by systemic inflammation and immune deficiency, is linked to gut dysbiosis. Though the systemic inflammation hypothesis starts to link gut dysbiosis to decompensated cirrhosis from a clinical perspective, a clearer demonstration is still needed for the role of the gut-liver-immune axis in cirrhosis progression. This review discusses the different immune states of the gut-liver axis in both healthy and cirrhotic settings and, more importantly, summarizes the current evidence about how microbiota-derived immune remodeling contributes to the progression of hepatic cirrhosis via the gut-liver axis.

Hepatic Encephalopathy: Current and Emerging Treatment Modalities

Hepatic encephalopathy (HE) is a potentially reversible neurocognitive complication of cirrhosis. It has been reported in at least 30% of patients with cirrhosis and imposes a significant economic burden on caregivers and the healthcare system. Ammonia has been recognized as the culprit in HE development, and all the currently approved treatments mostly act on this toxin to help with HE resolution. After a brief overview of HE characteristics and pathophysiology, this review explores the current accepted treatments for this debilitating complication of cirrhosis. This is followed by an overview of the novel available therapies and a brief focus on future treatment modalities for HE.

Medikamentöse Therapie bei Patienten mit Leberzirrhose

Die Leberzirrhose ist das Endstadium chronischer Lebererkrankungen und insbesondere im fortgeschrittenen Stadium mit einer hohen Morbidität und Mortalität verbunden. Patienten mit Leberfunktionseinschränkung sind permanent von einer Vielzahl schwerwiegender Komplikationen bedroht. Ein optimales pharmakologisches Management bei Patienten mit Leberinsuffizienz kann die Progression der Grunderkrankung verlangsamen, Hospitalisationen verhindern sowie Lebensqualität und Überleben verbessern. Dieser Artikel gibt einen Überblick über den aktuellen Stand und neue Entwicklungen der Pharmakotherapie bei Patienten mit Leberzirrhose.

Distinct responsiveness to rifaximin in patients with hepatic encephalopathy depends on functional gut microbial species

Hepatic encephalopathy (HE) is the neuropsychiatric complication of liver cirrhosis (LC). The influence of gut microbiota on HE pathogenesis has been suggested but not precisely elucidated. Here, we investigate how the gut microbial profile changed in patients with HE to clarify the functional gut microbial species associated with HE. We focused on their responses to rifaximin (RFX), a nonabsorbable antibiotic used in HE therapy. Feces samples were collected from patients with decompensated LC (all HE), patients with compensated LC, and healthy controls, and fecal gut microbial profiles were compared using 16S ribosomal RNA gene amplicon and metagenomic sequencing. The linear discriminant analysis effect size was used to identify specific species. Urease-positive Streptococcus salivarius, which can produce ammonia, was identified as the most significantly abundant gut microbiota in the HE group, and its ability to elevate the levels of blood ammonia as well as brain glutamine was experimentally verified in mice. Urease-negative Ruminococcus gnavus was also identified as a significantly abundant species in patients with RFX-nonresponsive HE after RFX administration. Interestingly, R. gnavus enhanced urease activity of recombinant urease itself, implying that R. gnavus could amplify ammonia production of surrounding urease-positive microbiota. Furthermore, the sensitivity of S. salivarius and R. gnavus to RFX depended on conjugated secondary bile acid levels, suggesting a therapeutic potential of the combined use of secondary bile acid levels with RFX for enhancing the efficacy of RFX. This study identified specific gut bacterial species abundant in patients with HE and verified their functions linked to HE pathophysiology. Targeting these bacteria could be a potentially effective strategy to treat HE.

Fecal Microbiota Transplantation as New Therapeutic Avenue for Human Diseases

The human body is home to a variety of micro-organisms. Most of these microbial communities reside in the gut and are referred to as gut microbiota. Over the last decades, compelling evidence showed that a number of human pathologies are associated with microbiota dysbiosis, thereby suggesting that the reinstatement of physiological microflora balance and composition might ameliorate the clinical symptoms. Among possible microbiota-targeted interventions, pre/pro-biotics supplementations were shown to provide effective results, but the main limitation remains in the limited microbial species available as probiotics. Differently, fecal microbiota transplantation involves the transplantation of a solution of fecal matter from a donor into the intestinal tract of a recipient in order to directly change the recipient's gut microbial composition aiming to confer a health benefit. Firstly used in the 4th century in traditional Chinese medicine, nowadays, it has been exploited so far to treat recurrent Clostridioides difficile infections, but accumulating data coming from a number of clinical trials clearly indicate that fecal microbiota transplantation may also carry the therapeutic potential for a number of other conditions ranging from gastrointestinal to liver diseases, from cancer to inflammatory, infectious, autoimmune diseases and brain disorders, obesity, and metabolic syndrome. In this review, we will summarize the commonly used preparation and delivery methods, comprehensively review the evidence obtained in clinical trials in different human conditions and discuss the variability in the results and the pivotal importance of donor selection. The final aim is to stimulate discussion and open new therapeutic perspectives among experts in the use of fecal microbiota transplantation not only in Clostridioides difficile infection but as one of the first strategies to be used to ameliorate a number of human conditions.

Potential Gut Microbiota Features for Non-Invasive Detection of Schistosomiasis

The gut microbiota has been identified as a predictive biomarker for various diseases. However, few studies focused on the diagnostic accuracy of gut microbiota derived-signature for predicting hepatic injuries in schistosomiasis. Here, we characterized the gut microbiomes from 94 human and mouse stool samples using 16S rRNA gene sequencing. The diversity and composition of gut microbiomes in Schistosoma japonicum infection-induced disease changed significantly. Gut microbes, such as Bacteroides, Blautia, Enterococcus, Alloprevotella, Parabacteroides and Mucispirillum, showed a significant correlation with the level of hepatic granuloma, fibrosis, hydroxyproline, ALT or AST in S. japonicum infection-induced disease. We identified a range of gut bacterial features to distinguish schistosomiasis from hepatic injuries using the random forest classifier model, LEfSe and STAMP analysis. Significant features Bacteroides, Blautia, and Enterococcus and their combinations have a robust predictive accuracy (AUC: from 0.8182 to 0.9639) for detecting liver injuries induced by S. japonicum infection in humans and mice. Our study revealed associations between gut microbiota features and physiopathology and serological shifts of schistosomiasis and provided preliminary evidence for novel gut microbiota-derived features for the non-invasive detection of schistosomiasis.

Clostridioides difficile Infection in Liver Cirrhosis: A Concise Review

Clostridium difficile is a Gram-positive bacillus with fecal-oral transmission and is currently one of the most common nosocomial infections worldwide, which was renamed Clostridioides difficile in 2016. Clostridioides difficile infection (CDI) is a prevalent infection in cirrhosis and negatively affects prognosis. This study aimed to provide a concise review with clinical practice implications. The prevalence of CDI in cirrhotic patients increases, while the associated mortality decreases. Multiple groups of risk factors increase the likelihood of CDI in patients with cirrhosis, such as antibiotic use, the severity of cirrhosis, some comorbidities, and demographic aspects. Treatment in the general population is currently described in the latest guidelines. In patients with cirrhosis, rifaximin and lactulose have been shown to reduce CDI risk due to their modulatory effects on the intestinal flora, although conflicting results exist. Fecal microbiota transplantation (FMT) as a treatment for the second or subsequent CDI recurrences has demonstrated a good safety and efficacy in cirrhosis and CDI. Future validation in more prospective studies is needed. Screening of asymptomatic patients appears to be discouraged for the prevention currently, with strict hand hygiene and cleaning of the ward and medical equipment surfaces being the cornerstone of minimizing transmission.

Safety and efficacy of fecal microbiota transplantation for treatment of systemic lupus erythematosus: An EXPLORER trial

Gut microbiota dysbiosis is involved in the development of systemic lupus erythematosus (SLE). The safety and efficacy of fecal microbiota transplantation (FMT) for the treatment of SLE patients has not been explored. In this 12-week, single-arm pilot clinical trial of oral encapsulated fecal microbiome from healthy donors to patients with active SLE, we aimed to evaluate the safety and efficacy of FMT in patients with SLE (ChiCTR2000036352). 20 SLE patients with SLEDAI ≥6 were recruited. FMT was administered once a week for three consecutive weeks along with standard treatment and the patients were followed for 12 weeks. Safety was evaluated throughout the trial. The primary endpoint was the SLE Responder Index-4 (SRI-4) at week 12. Microbiome composition, levels of short chain fatty acids (SCFAs) in the gut and of cytokines in the sera were measured along with lymphocyte phenotyping. No serious adverse events were observed after FMT. At week 12, the SRI-4 response rate was 42.12%, and significant reductions in the SLEDAI-2K scores and the level of serum anti-dsDNA antibody were observed compared to baseline. Significant enrichment of SCFAs-producing bacterial taxa and reduction of inflammation-related bacterial taxa were observed, along with increased production of SCFAs in the gut and reduced levels of IL-6 and CD4⁺ memory/naïve ratio in the peripheral blood. Furthermore, SRI-4 responding patients displayed specific microbiota signatures both before and after FMT. The first clinical trial of FMT in active SLE patients provide supportive evidence that FMT might be a feasible, safe, and potentially effective therapy in SLE patients by modifying the gut microbiome and its metabolic profile.

Promises of microbiome-based therapies

Humans harbour large quantities of microbes, including bacteria, fungi, viruses and archaea, in the gut. Patients with liver disease exhibit changes in the intestinal microbiota and gut barrier dysfunction. Preclinical models demonstrate the importance of the gut microbiota in the pathogenesis of various liver diseases. In this review, we discuss how manipulation of the gut microbiota can be used as a novel treatment approach for liver disease. We summarise current data on untargeted approaches, including probiotics and faecal microbiota transplantation, and precision microbiome-centered therapies, including engineered bacteria, postbiotics and phages, for the treatment of liver diseases.

Albumin therapy for hepatic encephalopathy: current evidence and controversies

Hepatic encephalopathy (HE) is a common complication that occurs in 16-21% of end-stage cirrhosis patients. Emerging evidence suggests that systemic inflammation and oxidative stress may play a role in the development of HE. Recent understanding on the anti-inflammatory properties of human albumin has led to growing interest of using human albumin for the treatment and prevention of HE among decompensated patients. In this review, we aim to discuss the current evidence and controversies of using human albumin for the treatment and prevention of HE in advanced cirrhosis patients.

A Systematic Review of the Efficacy and Safety of Fecal Microbiota Transplantation in the Treatment of Hepatic Encephalopathy and Clostridioides difficile Infection in Patients With Cirrhosis

The microbiome of the human gut and liver coexists by influencing the health and disease state of each system. Fecal microbiota transplantation (FMT) has recently emerged as a potential treatment for conditions associated with cirrhosis, such as hepatic encephalopathy and recurrent/refractory Clostridioides difficile infection (rCDI). We have conducted a systematic review of the safety and efficacy of FMT in treating hepatic encephalopathy and rCDI. A literature search was performed using variations of the keywords "fecal microbiota transplant" and "cirrhosis" on PubMed/MEDLINE from inception to October 3, 2021. The resulting 116 articles were independently reviewed by two authors. Eight qualifying studies were included in the systematic review. A total of 127 cirrhotic patients received FMT. Hepatic encephalopathy was evaluated by cognitive tests, such as the Psychometric Hepatic Encephalopathy Score (PHES) and EncephalApp Stroop test. Not only was there an improvement in the cognitive performance in the FMT cohort, but the improvement was also maintained throughout long-term follow-up. In the treatment of rCDI, the FMT success rate is similar between cirrhotic patients and the general population, although more than one dose may be needed in the former. The rate of serious adverse events and adverse events in the cirrhotic cohort was slightly higher than that in the general population but was low overall. We found evidence that supports the therapeutic potential and safety profile of FMT to treat hepatic encephalopathy and rCDI in cirrhotic patients. Further research will be beneficial to better understand the role of FMT in cirrhosis.

Hepatocellular Carcinoma: How the Gut Microbiota Contributes to Pathogenesis, Diagnosis, and Therapy

The gut microbiota is gaining increasing attention, and the concept of the "gut-liver axis" is gradually being recognized. Leaky gut resulting from injury and/or inflammation can cause the translocation of flora to the liver. Microbiota-associated metabolites and components mediate the activation of a series of signalling pathways, thereby playing an important role in the development of hepatocellular carcinoma (HCC). For this reason, targeting the gut microbiota in the diagnosis, prevention, and treatment of HCC holds great promise. In this review, we summarize the gut microbiota and the mechanisms by which it mediates HCC development, and the characteristic alterations in the gut microbiota during HCC pathogenesis. Furthermore, we propose several strategies to target the gut microbiota for the prevention and treatment of HCC, including antibiotics, probiotics, faecal microbiota transplantation, and immunotherapy.

Implications and Management of Cirrhosis-Associated Immune Dysfunction Before and After Liver Transplantation

Cirrhosis-associated immune dysfunction (CAID) describes a panacea of innate and adaptive deficits that result from the sequelae of cirrhotic portal hypertension that is similar in its manifestations regardless of etiology of chronic liver injury. CAID is associated with synchronous observations of dysregulated priming of innate immune effector cells that demonstrate a proinflammatory phenotype but are functionally impaired and unable to adequately prevent invading pathogens. CAID is mainly driven by gut-barrier dysfunction and is associated with deficits of microbial compartmentalization and homeostasis that lead to tonic activation, systemic inflammation, and exhaustion of innate-immune cells. CAID leads to a high frequency of bacterial and fungal infections in patients with cirrhosis that are often associated with acute decompensation of chronic liver disease and acute-on-chronic liver failure and carry a high mortality rate. Understanding the deficits of mucosal and systemic immunity in the context of chronic liver disease is essential to improving care for patients with cirrhosis, preventing precipitants of acute decompensation of cirrhosis, and improving morbidity and survival. In this review, we summarize the detailed dynamic immunological perturbations associated with advanced chronic liver disease and highlight the importance of recognizing immune dysregulation as a sequela of cirrhosis. Furthermore, we address the role of screening, prevention, and early treatment of infections in cirrhosis in improving patient outcomes in transplant and nontransplant settings.

Effect of a specific Escherichia coli Nissle 1917 strain on minimal/mild hepatic encephalopathy treatment

BACKGROUND

Hepatic encephalopathy (HE) can be considered a result of dysregulated gut-liver-brain axis function, where cognitive impairment can be reversed or prevented by the beneficial effects induced by "gut-centric" therapies, such as the administration of nonabsorbable disaccharides, nonabsorbable antibiotics, probiotics and prebiotics.

AIM

To assess the short-term efficacy and safety of the probiotic Escherichia coli Nissle (EcN) 1917 strain compared to lactulose and rifaximin in patients with minimal/mild HE.

METHODS

From January 2017 to March 2020, a total of 45 patients with HE were enrolled in this prospective, single-centre, open-label, randomized study. Participants were randomly assigned at a ratio of 1:1:1 to one of the treatment groups: The EcN group (n = 15), lactulose group (n = 15) or rifaximin group (n = 15) for a 1 mo intervention period. The main primary outcomes of the study were changes in serum ammonia and Stroop test score. The secondary outcomes were markers of a chronic systemic inflammatory response (ІL-6, ІL-8, and IFN-γ) and bacteriology of the stool flora evaluated by specialized nonculture techniques after a 1 mo intervention period.

RESULTS

Patients who were given rifaximin or EcN showed a more significant reduction in serum ammonia and normalization of Bifidobacteria and Lactobacilli abundance compared to the lactulose group. However, the most pronounced restoration of the symbiotic microflora was associated with EcN administration and characterized by the absence of E. coli with altered properties and pathogenic enterobacteria in patient faeces. In the primary outcome analysis, improvements in the Stroop test parameters in all intervention groups were observed. Moreover, EcN-treated patients performed 15% faster on the Stroop test than the lactulose group patients (P = 0.017). Both EcN and rifaximin produced similar significant reductions in the proinflammatory cytokines INF-γ, IL-6 and IL-8. EcN was more efficient than lactulose in reducing proinflammatory cytokine levels.

CONCLUSION

The use of the probiotic EcN strain was safe and quite efficient for HE treatment. The probiotic reduced the ammonia content and the level of serum proinflammatory cytokines, normalized the gut microbiota composition and improved the cognitive function of patients with HE. The application of the EcN strain was more effective than lactulose treatment.

Clinical Practice Guidelines for Fecal Microbiota Transplantation in Korea

Fecal microbiota transplantation (FMT) is a highly efficacious and safe modality for the treatment of recurrent or refractory Clostridioides difficile infection (CDI), with overall success rates of 90%. Thus, FMT has been widely used for 10 years. The incidence and clinical characteristics of CDI, the main indication for FMT, differ between countries. To date, several guidelines have been published. However, most of them were published in Western countries and therefore cannot represent the Korean national healthcare systems. One of the barriers to performing FMT is a lack of national guidelines. Accordingly, multidisciplinary experts in this field have developed practical guidelines for FMT. The purpose of these guidelines is to aid physicians performing FMT, which can be adapted to treat CDI and other conditions.

Current Status and Future Therapeutic Options for Fecal Microbiota Transplantation

The intestinal microbiota plays an important role in maintaining human health, and its alteration is now associated with the development of various gastrointestinal (ulcerative colitis, irritable bowel syndrome, constipation, etc.) and extraintestinal diseases, such as cancer, metabolic syndrome, neuropsychiatric diseases. In this context, it is not surprising that gut microbiota modification methods may constitute a therapy whose potential has not yet been fully investigated. In this regard, the most interesting method is thought to be fecal microbiota transplantation, which consists of the simultaneous replacement of the intestinal microbiota of a sick recipient with fecal material from a healthy donor. This review summarizes the most interesting findings on the application of fecal microbiota transplantation in gastrointestinal and extraintestinal pathologies.

Long-term Outcomes of Stool Transplant in Alcohol-associated Hepatitis-Analysis of Clinical Outcomes, Relapse, Gut Microbiota and Comparisons with Standard Care

BACKGROUND

Healthy donor fecal microbiota transplantation (FMT) was preliminarily shown to have clinical benefits in hepatic encephalopathy (HE), severe alcohol-associated hepatitis (SAH), and alcohol use disorder. However, the long-term outcomes of FMT and the gut microbiota (GM) changes in patients with SAH are unknown.

METHODS

Patients with SAH who underwent FMT (N = 35) or standard of care (SoC, N = 26) from May 2017 to June 2018 were included, and their stored stool samples were analyzed prospectively. Clinical outcomes, including infections, hospitalizations, critical illness, alcohol relapse, and survival, were evaluated. Metagenomic analysis was undertaken to identify the relative abundances (Ras) and significant taxa at baseline and post-therapy (up to three years) among survivors between the two groups.

RESULTS

At follow-up, the incidences of ascites, HE, infections, and major hospitalizations were significantly higher in the SoC than in the FMT group (P < 0.05). Alcohol relapse was lower (28.6% versus 53.8%), and the time to relapse was higher in the FMT than in the SoC group (P = 0.04). Three-year survival was higher in the FMT than in the SoC group (65.7% versus 38.5%, P = 0.052). Death due to sepsis was significantly higher in the SoC group (N = 13/16, 81.2%; P = 0.008). GM analysis showed a significant increase in the RA of Bifidobacterium and a reduction in the RA of Acinetobacter in the FMT group. Beyond one to two years, the RA of Porphyromonas was significantly higher and that of Bifidobacterium was lower in the SoC than in the FMT group.

CONCLUSIONS

In terms of treatment for patients with SAH, healthy donor FMT is associated with significantly lesser ascites, infections, encephalopathy, and alcohol relapse (with a trend toward higher survival rates) than SoC, associated with beneficial GM modulation. Larger controlled studies on FMT are an unmet need.

Gut Barrier and Microbiota in Cirrhosis

Gut microbiota and their homeostatic functions are central to the maintenance of the intestinal mucosal barrier. The gut barrier functions as a structural, biological, and immunological barrier, preventing local and systemic invasion and inflammation of pathogenic taxa, resulting in the propagation or causation of organ-specific (liver disease) or systemic diseases (sepsis) in the host. In health, commensal bacteria are involved in regulating pathogenic bacteria, sinister bacterial products, and antigens; and help control and kill pathogenic organisms by secreting antimicrobial metabolites. Gut microbiota also participates in the extraction, synthesis, and absorption of nutrient metabolites, maintains intestinal epithelial integrity and regulates the development, homeostasis, and function of innate and adaptive immune cells. Cirrhosis is associated with local and systemic immune, vascular, and inflammatory changes directly or indirectly linked to perturbations in quality and quantity of intestinal microbiota and intestinal mucosal integrity. Dysbiosis and gut barrier dysfunction are directly involved in the pathogenesis of compensated cirrhosis and the type and severity of complications in decompensated cirrhosis, such as bacterial infections, encephalopathy, extrahepatic organ failure, and progression to acute on chronic liver failure. This paper reviews the normal gut barrier, gut barrier dysfunction, and dysbiosis-associated clinical events in patients with cirrhosis. The role of dietary interventions, antibiotics, prebiotics, probiotics, synbiotics, and healthy donor fecal microbiota transplantation (FMT) to modulate the gut microbiota for improving patient outcomes is further discussed.

Novel drug discovery strategies for the treatment of decompensated cirrhosis

INTRODUCTION

Disease progression in cirrhosis leads to decompensation and acute-on-chronic liver failure (ACLF), which is characterized by organ failure and high mortality. Portal hypertension and cardiovascular dysfunction trigger the development of cirrhosis-related complications whilst tissue injury and cellular metabolic dysfunction lead to organ failure. System inflammation is the overarching mechanism mediating both the transition from compensation to decompensation as well as progression to ACLF. Treatment of precipitating events and intensive organ support is the only established therapeutic strategies. Liver transplantationrepresents the only curative therapy but contraindications and organ scarcity limit its availability to only a minority of patients with end-stage liver disease. Therefore, the discovery and development of novel interventions modifying the disease course and improving patients' outcome are of utmost importance.

AREAS COVERED

This review highlights and discusses therapeutic novelties in the field of end-stage liver disease.

EXPERT OPINION

Despite decades of research, there are still no established therapies to improve the devastating prognosis of patients with end-stage liver disease. The clinical heterogeneity and complex pathogenesis will put high demands on drug discovery. Combinatorial therapies tailored to the patients' individual pattern of pathomechanisms may be the most efficient way to modify disease course.

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

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

Microbiota transplants from feces or gut content attenuated portal hypertension and portosystemic collaterals in cirrhotic rats

Liver cirrhosis and portal hypertension is the end of chronic liver injury with hepatic, splanchnic and portosystemic collateral systems dysregulation. Liver injury is accompanied by gut dysbiosis whereas dysbiosis induces liver fibrosis, splanchnic angiogenesis and dysregulated vascular tones vice versa, making portal hypertension aggravated. It has been proved that intestinal microbiota transplantation alleviates dysbiosis. Nevertheless, the influences of microbiota transplantation on cirrhosis-related portal hypertension are not so clear. Liver cirrhosis with portal hypertension was induced by bile duct ligation (BDL) in rats. Sham rats were surgical controls. Rats randomly received vehicle, fecal or gut (terminal ileum) material transplantation. The results showed that microbiota transplantation from feces or gut material significantly reduced portal pressure in cirrhotic rats (P=0.010, 0.044). Hepatic resistance, vascular contractility, fibrosis and relevant protein expressions were not significantly different among cirrhotic rats. However, microbiota transplantation ameliorated splanchnic hyperdynamic flow and vasodilatation. Mesenteric angiogenesis, defined by whole mesenteric window vascular density, decreased in both transplantation groups and phosphorylated endothelial nitric-oxide synthase (eNOS) was down-regulated. Portosystemic shunts determined by splenorenal shunt (SRS) flow decreased in both transplantation groups (P=0.037, 0.032). Shunting severity assessed by microsphere distribution method showed consistent results. Compared with sham rats, cirrhotic rats lacked Lachnospiraceae. Both microbiota transplants increased Bifidobacterium. In conclusion, microbiota transplantation in cirrhotic rats reduced portal pressure, alleviated splanchnic hyperdynamic circulation and portosystemic shunts. The main beneficial effects may be focused on portosystemic collaterals-related events, such as hepatic encephalopathy and gastroesophageal variceal hemorrhage. Further clinical investigations are mandatory.

Microbiome therapeutics for hepatic encephalopathy

Hepatic encephalopathy (HE) is a complication of cirrhosis characterised by neuropsychiatric and motor dysfunction. Microbiota-host interactions play an important role in HE pathogenesis. Therapies targeting microbial community composition and function have been explored for the treatment of HE. Prebiotics, probiotics and faecal microbiota transplant (FMT) have been used with the aim of increasing the abundance of potentially beneficial taxa, while antibiotics have been used to decrease the abundance of potentially harmful taxa. Other microbiome therapeutics, including postbiotics and absorbents, have been used to target microbial products. Microbiome-targeted therapies for HE have had some success, notably lactulose and rifaximin, with probiotics and FMT also showing promise. However, there remain several challenges to the effective application of microbiome therapeutics in HE, including the resilience of the microbiome to sustainable change and unpredictable clinical outcomes from microbiota alterations. Future work in this space should focus on rigorous trial design, microbiome therapy selection, and a personalised approach to HE.

Adverse events of fecal microbiota transplantation: a meta-analysis of high-quality studies

BACKGROUND

Fecal microbiota transplantation (FMT) has shown excellent efficacy in treating Clostridioides difficile infection, as well as promise in several other diseases. The heightened interest is accompanied by concerns over adverse events (AE) and safety. To further understand that in FMT, we performed a systematic review of the literature and a meta-analysis of high-quality, prospective randomized controlled trials FMT.

METHODS

Studies were selected based on predefined exclusion criteria and were assessed for quality. Only prospective, randomized, controlled studies of high quality were included in the final analysis. Data were extracted on demographics, AE, indication, delivery method and follow-up duration.

RESULTS

Out of 334 articles reviewed, 9 high quality studies with 756 FMTs were selected for final analysis. The pooled rate of AE was 39.3% (95% confidence interval [CI] 0.19-0.642) as they were reported by 112 patients who received FMT. The SAE rate was 5.3% (95%CI 3.1-8.8%). The most common AE reported was abdominal pain, followed by diarrhea. The most common SAE was Clostridium difficile infection. Upper gastrointestinal tract delivery was associated with a higher rate of total AE, but not SAE.

CONCLUSIONS

Based on the selected studies, the AE rate of FMT is 39.3%, with most AE being mild and self-limiting. SAE were uncommon at 5.3%, and many were only possibly related to the FMT. Adherence to standardized reporting of AE as well as longitudinal studies and registries will help further clarify the safety of FMT in the future.

Fecal Microbiota Transplantation as a Tool for Therapeutic Modulation of Non-gastrointestinal Disorders

Fecal microbiota transplantation has been primarily investigated as a therapeutic tool for a number of gut disorders. Optimistic results from clinical studies on Clostridium difficile infection, inflammatory bowel disease and irritable bowel syndrome have stimulated the expansion of possible indications in which FMT might represent a game changing approach. Microbial dysbiosis was shown in a number of non-gastrointestinal disorders. Moreover, FMT was proven to be effective in therapy of numerous animal models of disease. However, only a proportion of these disorders have been addressed in clinical studies using FMT. These include obesity, non-alcoholic fatty liver disease, cardiovascular inflammation and neurological disorders such as autism, depression and Parkinson's disease. Results from preclinical and clinical studies also outlined possible molecular mechanisms that contribute to alleviation of the disease. These range from increasing the circulating levels of microbial metabolites (trimethylamine N-oxide, lipopolysaccharide, short chain fatty acids) to stimulation of the enteric nervous system. Several methodological shortcomings are still to be addressed; however, positive results of the clinical studies indicate that further investigation of FMT as a therapeutic tool for non-gastrointestinal disorders can be expected in upcoming years.