Effects of probiotic therapy on hepatic encephalopathy in patients with liver cirrhosis: an updated meta-analysis of six randomized controlled trials

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.

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

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

Clostridium butyricum Bacteremia Associated with Probiotic Use, Japan

Clostridium butyricum, a probiotic commonly prescribed in Asia, most notably as MIYA-BM (Miyarisan Pharmaceutical Co., Ltd.; https://www.miyarisan.com), occasionally leads to bacteremia. The prevalence and characteristics of C. butyricum bacteremia and its bacteriologic and genetic underpinnings remain unknown. We retrospectively investigated patients admitted to Osaka University Hospital during September 2011-February 2023. Whole-genome sequencing revealed 5 (0.08%) cases of C. butyricum bacteremia among 6,576 case-patients who had blood cultures positive for any bacteria. Four patients consumed MIYA-BM, and 1 patient consumed a different C. butyricum-containing probiotic. Most patients had compromised immune systems, and common symptoms included fever and abdominal distress. One patient died of nonocclusive mesenteric ischemia. Sequencing results confirmed that all identified C. butyricum bacteremia strains were probiotic derivatives. Our findings underscore the risk for bacteremia resulting from probiotic use, especially in hospitalized patients, necessitating judicious prescription practices.

Effect of probiotics on nutritional status, biochemical parameters, and disease severity in cirrhotic patients referred for liver transplantation-A randomised double blind, placebo-controlled trial

INTRODUCTION

Probiotics have been shown to be effective in many diseases. However, their effects on the nutritional status in patients with cirrhosis is uncertain.

AIM

We aimed to study the effect of probiotics on nutritional status, biochemical parameters, and liver disease severity in patients with cirrhosis referred for liver transplantation.

METHODS

A randomised, double-blind, placebo-controlled study was conducted from July 2021-October 2022. A total of 215 patients with cirrhosis referred for liver transplantation were enrolled and randomised to two groups to receive either probiotics (VSL#3, Sun Pharma, India, 112.5 billion colony-forming units (cfu) containing eight strains of bacteria) or placebo (corn starch filled capsules), two capsules/day for six weeks. Nutritional assessment was done, and biochemical parameters were measured before and after the intervention.

RESULTS

Nutritional assessment parameters like body mass index (p = 0.001), triceps skin fold thickness (p = 0.011), muscle strength (p = 0.007) and subjective global assessment scores (p < 0.000) showed a positive trend in the probiotic group. Probiotic intake also significantly downregulated direct bilirubin levels (p = 0.043) and increased albumin levels compared to baseline, but other biochemical parameters remained unchanged. Child Turcotte Pugh score also decreased significantly compared to pre therapy (p = 0.0001). These changes were not observed in the placebo group. Moreover, probiotic VSL#3 supplementation was safe and well-tolerable without any adverse events in patients with cirrhosis.

CONCLUSION

Probiotic VSL#3 supplementation improved the nutritional status, reduced the severity of liver disease and was safe and tolerable in patients with cirrhosis.

TRIAL REGISTRATION

www.ctri.nic.in (CTRI/2021/07/034917).

Role of Probiotics in Patients with Allergic Rhinitis: A Systematic Review of Systematic Reviews

Introduction Allergic rhinitis (AR) is estimated to affect up to 30% of the world population. With the rise in cases, newer treatment modalities have been explored. Probiotics have shown to reduce symptoms of AR and improve quality of life. A few systematic reviews have been published aiming to assess the role of probiotics in AR.

Objectives To consolidate the recent evidence with an overview of systematic reviews by extracting data regarding subjective outcomes (from quality of life questionnaires, the Total Nasal Symptom Score, the Total Ocular Symptom Score, the Daily Total Symptom Score, the incidence of AR, and the Rhinitis Total Symptom Score) and objective outcomes (levels of antigen-specific immunoglobulin E [IgE], total IgE, interleukin 10 [IL-10], interferon gamma [IFNG], eosinophil, and the T helper 1/T helper 2 [Th1/Th2] ratio).

Data Synthesis We conducted a literature search on the PubMed, EBSCO CINAHL, EBSCO Dentistry & Oral Sciences Source, and Cochrane Library up to April 14, 2020. The qualitative assessment was performed using the Assessing the Methodological Quality of Systematic Reviews (AMSTAR-2) tool. A total of 419 titles were screened, and 3 systematic reviews met our eligibility criteria. Probiotics in the treatment of AR have been shown to improve quality of life, the total nasal and ocular symptom scores, the daily total symptom scores and Th1/Th2 ratio. No difference was ascertained for rhinitis total symptom score, and the rates of antigen-specific IgE, total IgE, IL-10, INFG and eosinophil.

Conclusion The present review showed that there is considerable evidence that probiotics are useful in the treatment of AR. Further randomized trials targeting the limitations of the currently-available evidence can help ascertain the usefulness of probiotics in cases of AR.

Probiotics in the treatment of gastrointestinal diseases

The human microbiota has a tremendous effect on our health. In the last decades, our knowledge about interactions between bacteria and humans have grown greatly. Not only is it necessary for humans to synthesize vitamins, to have tight intestinal barriers or protect from pathogens, it also has an impact on our immune system and thus plays an important role in autoimmune diseases and prevention of excessive inflammatory response. The idea of probiotics is to restore the balance in humans digestive microbiota. There is a growing number of scientific papers that proves a positive impact of using probiotics in various diseases. However, there are still questions that need to be answered before probiotics play a bigger role in the treatment. This paper presents the information about the use of probiotics in most common diseases of gastrointestinal tract.

Nutraceuticals & microbiota: review

Nutraceuticals are defined as products isolated or purified from foods that are generally sold in medicinal or dosage forms not usually associated with food which is demonstrated to have a physiological benefit or provide protection against chronic disease. In this context, the products offered should be rigorously evaluated by international regulatory agencies. More recently, nutraceuticals have been proposed as a potential preventive and therapeutic option in the assessment of chronic diseases, mainly by altering the microbiome composition. However, the current lack of conclusive evidence supporting the "healthy" or "normal" microbiome, along with the dysbiosis concept paradigm, could be both contributing to the lack of homogeneous results. These issues may be solved in the next years with the use of emergent technologies in the individual's microbiome assessment and its fluctuations in time or related to many factors, such as nutraceuticals. Additionally, future research assessing the independent association between the dysbiosis modification and any "potential" nutraceutical product (including bioactive ingredient or chemical compound in food) is going to enlarge the currently reduced "established nutraceuticals" group. In this work we have assessed the nutraceutical's potential role as a microbiome-targeted manipulation therapy, and the gut-liver axis involved in the digestive diseases' pathogenesis and progression, including the chronic liver diseases. Moreover, microbiome targeted nutraceuticals that show consistent results might be further included in clinical research and trials in the therapeutic assessment of chronic diseases. Finally, the indication of these quality microbiome-targeted nutraceuticals will undoubtedly carry health benefits for individuals.

From intestinal dysbiosis to alcohol-associated liver disease

Alcohol-associated intestinal dysbiosis and bacterial overgrowth can lead to a dysregulation of tryptophan metabolism and lower production of indoles. Several of these indole derivatives are aryl hydrocarbon receptor ligands that, in turn, are involved in antimicrobial defense via induction of interleukin-22 (IL-22). IL-22 increases the expression of intestinal regenerating islet-derived 3 (Reg3) lectins, which maintain low bacterial colonization of the inner mucus layer and reduce bacterial translocation to the liver. Chronic alcohol consumption is associated with reduced intestinal expression of Reg3β and Reg3γ, increased numbers of mucosa-associated bacteria and bacterial translocation. Translocated microbial products and viable bacteria reach the liver and activate the innate immune system. Release of inflammatory molecules promotes inflammation, contributes to hepatocyte death and results in a fibrotic response. This review summarizes the mechanisms by which chronic alcohol intake changes the gut microbiota and contributes to alcohol-associated liver disease by changing microbial-derived metabolites.

Nonpharmacologic Management of Hepatic Encephalopathy: An Update

Research increasingly shows that the gut-liver-brain axis is a crucial component in the pathophysiology of hepatic encephalopathy (HE). Due to the limitations of current standard-of-care medications, non-pharmacological treatments that target gut dysbiosis, including probiotics, nutritional management, and fecal microbiota transplants, are being considered as alternative and adjunct therapies. Meta-analyses note that probiotics could offer benefits in HE treatment, but have not shown superiority over lactulose. Emerging literature suggests that fecal microbiota transplants could offer a novel strategy to treat gut dysbiosis and favorably impact HE. Finally, liver support devices and liver transplantation could offer a last-resort treatment option for persistent HE.

Antimicrobial resistance in chronic liver disease

High levels of antimicrobial drug resistance deleteriously affecting the outcome of treatment with antibacterial agents are causing increasing concern worldwide. This is particularly worrying in patients with cirrhosis with a depressed immune system and heightened susceptibility to infection. Antibiotics have to be started early before results of microbiological culture are available. Current guidelines for the empirical choice of antibiotics in this situation are not very helpful, and embracing antimicrobial stewardship including rapid de-escalation of therapy are not sufficiently emphasised. Multi-drug resistant organism rates to quinolone drugs of up to 40% are recorded in patients with spontaneous bacterial peritonitis on prophylactic antibiotics, leading to a break-through recurrence of intra-peritoneal infection. Also considered in this review is the value of rifaximin-α, non-selective beta-blockers, and concerns around proton pump inhibitor drug use. Fecal microbial transplantation and other gut-targeting therapies in lessening gut bacterial translocation are a promising approach, and new molecular techniques for determining bacterial sensitivity will allow more specific targeted therapy.

Bifidobacterium spp: the promising Trojan Horse in the era of precision oncology

Selective delivery of therapeutic agents into solid tumors has been a major challenge impeding the achievement of long-term disease remission and cure. The need to develop alternative drug delivery routes to achieve higher drug concentration in tumor tissue, reduce unwanted off-target side effects and thus achieve greater therapeutic efficacy, has resulted in an explosive body of research. Bifidobacterium spp. are anaerobic, nonpathogenic, Gram-positive bacteria, commensal to the human gut that are a possible anticancer drug-delivery vehicle. In this review, we describe Bifidobacterium's microbiology, current clinical applications, overview of the preclinical work investigating Bifidobacterium's potential to deliver anticancer therapy, and review the different strategies used up to date. Finally, we discuss both current challenges and future prospects.

Diagnosis and management of hepatic encephalopathy

Overt and covert hepatic encephalopathy (HE) are debilitating complications of cirrhosis. HE results in a poor quality of life for patients and their caregivers and, unless there is access to liver transplantation, the prognosis is poor. The development of overt HE is often unpredictable, and its management, particularly in the ward, remains challenging. There is an urgent need for novel approaches to treat HE. Until recently, therapies for this complication were disappointing, with frequently intolerable side effects such as diarrhoea and faecal incontinence. However, a non-absorbable antibiotic, rifaximin, * has been approved for the prevention of recurrent overt HE. It aims to reduce hospitalisation and resource use, as well as improve patients' quality of life. This article describes the practical aspects of diagnosing, classifying and managing HE. It reviews the pharmacological options for the treatment and prophylaxis of overt HE, and explores the evidence base demonstrating that rifaximin reduces the recurrence of overt HE.

Gut Microbiome-based Therapeutics in Liver Cirrhosis: Basic Consideration for the Next Step

Infections account for significant morbidity and mortality in liver cirrhosis and most are related to the gut microbiome. Fecal dysbiosis, characterized by an overgrowth of potentially pathogenic bacteria and a decrease in autochthonous non-pathogenic bacteria, becomes prominent with the progression of liver cirrhosis. In cirrhotic patients, disruption of the intestinal barrier causes intestinal hyperpermeability (i.e. leaky gut), which is closely related to gut dysmotility, dysbiosis and small intestinal bacterial overgrowth and may induce pathological bacterial translocation. Although the involved microbial taxa are somewhat different between the cirrhotic patients from the East and the West, the common manifestation of a shortage of bacteria that contribute to the production of short-chain fatty acids and secondary bile acids may facilitate intestinal inflammation, leaky gut and gut dysbiosis. Translocated endotoxin and bacterial DNA are capable of provoking potent inflammation and affecting the metabolic and hemodynamic systems, which may ultimately enhance the progression of liver cirrhosis and its various complications, such as hepatic encephalopathy (HE), variceal bleeding, infection and renal disturbances. Among studies on the microbiome-based therapeutics, findings of probiotic effects on HE have been contradictory in spite of several supportive results. However, the effects of synbiotics and prebiotics are substantially documented. The background of their effectiveness should be evaluated again in relation to the cirrhosis-related changes in gut microbiome and their metabolic effects. Strict indications for the antibiotic rifaximin remain unestablished, although its effect is promising, improving HE and other complications with little influence on microbial populations. The final goal of microbiome-based therapeutics is to adjust the gut-liver axis to the maximal benefit of cirrhotic patients, with the aid of evolving metagenomic and metabolomic analyses.

Using probiotics in clinical practice: Where are we now? A review of existing meta-analyses

The scientific literature has demonstrated that probiotics have a broad spectrum of activity, although often the results are contradictory. This study provides a critical overview of the current meta-analyses that have evaluated the efficacy of probiotics in physiologic and pathological conditions, such as metabolic disease, antibiotic-associated and Clostridium difficile-associated diarrhea, IBS, constipation, IBD, chemotherapy-associated diarrhea, respiratory tract infection, ventilator-associated pneumonia, NAFLD, liver encephalopathy, periodontitis, depression, vaginosis, urinary tract infections, pancreatitis, incidence of ventilator-associated pneumonia, hospital infection and stay in ICU, mortality of post-trauma patients, necrotising enterocolitis in premature infants. Only for antibiotic- and Clostridium difficile-associated diarrhea, and respiratory tract infections the effects of probiotics are considered "evidence-based." Concerning other fields, meta-analyses lacks to define type and biologic effect of probiotic strains, as well as the outcome in a disease state. Therefore, the results presented should be a stimulus for further studies which will provide clinical recommendations.

Novel Indications for Fecal Microbial Transplantation: Update and Review of the Literature

BACKGROUND AND AIMS

Fecal microbial transplantation (FMT) is an established successful treatment modality for recurrent Clostridium difficile infection (CDI). The safety profile and potential therapeutic advantages of FMT for diseases associated with dysbiosis and immune dysfunction have led to many publications, mainly case series, and while many studies and reviews have been published on the use of FMT for inflammatory bowel disease (IBD), its potential use for other disease conditions has not been thoroughly reviewed. The aim of this review was to investigate the evidence surrounding the use of FMT in conditions other than IBD and CDI.

METHODS

A PubMed search was performed using the terms "Fecal microbiota transplantation" OR "FMT" OR "Bacteriotherapy."

RESULTS

A total of 26 articles describing the use of FMT in a variety of both intra-and extraintestinal disease conditions including gastrointestinal, hematologic, neurologic, metabolic, infectious, and autoimmune disorders have been included in this review and have demonstrated some positive results. The studies included were case reports, case series, controlled trials, and cohort studies.

CONCLUSIONS

The findings of these studies demonstrate that FMT, particularly in conditions associated with gastrointestinal dysbiosis, shows promise to provide another effective tool in the therapeutic armament of the practicing physician. FMT was found to be possibly effective in various diseases, mostly associated with enteric dysbiosis or with immune dysfunction. Randomized clinical studies on large populations should be performed to explore the effectiveness of this therapy, and basic research studies should be designed to gain understanding of the mechanisms through which impact these disorders.

The Effects of Probiotics and Symbiotics on Risk Factors for Hepatic Encephalopathy: A Systematic Review

Alterations in the levels of intestinal microbiota, endotoxemia, and inflammation are novel areas of interest in the pathogenesis of hepatic encephalopathy (HE). Probiotics and symbiotics are a promising treatment option for HE due to possible beneficial effects in modulating gut microflora and might be better tolerated and more cost-effective than the traditional treatment with lactulose, rifaximin or L-ornithine-L-aspartate. A systematic search of the electronic databases PubMed, ISI Web of Science, EMBASE, and Cochrane Library was conducted for randomized controlled clinical trials in adult patients with cirrhosis, evaluating the effect of probiotics and symbiotics in changes on intestinal microflora, reduction of endotoxemia, inflammation, and ammonia, reversal of minimal hepatic encephalopathy (MHE), prevention of overt hepatic encephalopathy (OHE), and improvement of quality of life. Nineteen trials met the inclusion criteria. Probiotics and symbiotics increased beneficial microflora and decreased pathogenic bacteria and endotoxemia compared with placebo/no treatment, but no effect was observed on inflammation. Probiotics significantly reversed MHE [risk ratio, 1.53; 95% confidence interval (CI): 1.14, 2.05; P=0.005] and reduced OHE development (risk ratio, 0.62; 95% CI: 0.48, 0.80; P=0.0002) compared with placebo/no treatment. Symbiotics significantly decreased ammonia levels compared with placebo (15.24; 95% CI: -26.01, -4.47; P=0.006). Probiotics did not show any additional benefit on reversal of MHE and prevention of OHE development when compared with lactulose, rifaximin, and L-ornithine-L-aspartate. Only 5 trials considered tolerance with minimal side effects reported. Although further research is warranted, probiotics and symbiotics should be considered as an alternative therapy for the treatment and management of HE given the results reported in this systematic review.

Hepatic encephalopathy: what the multidisciplinary team can do

Hepatic encephalopathy (HE) is a complex disease requiring a multidisciplinary approach among specialists, primary care team, family, and caregivers. HE is currently a diagnosis of exclusion, requiring an extensive workup to exclude other possible etiologies, including mental status changes, metabolic, infectious, traumatic, and iatrogenic causes. The categorization of HE encompasses a continuum, varying from the clinically silent minimal HE (MHE), which is only detectable using psychometric tests, to overt HE, which is further divided into four grades of severity. While there has been an increased effort to create fast and reliable methods for the detection of MHE, screening is still underperformed due to the lack of standardization and efficient methods of diagnosis. The management of HE requires consultation from various disciplines, including hepatology, primary care physicians, neurology, psychiatry, dietician/nutritionist, social workers, and other medical and surgical subspecialties based on clinical presentation and clear communication among these disciplines to best manage patients with HE throughout their course. The first-line therapy for HE is lactulose with or without rifaximin. Following the initial episode of overt HE, secondary prophylaxis with lactulose and/or rifaximin is indicated with the goal to prevent recurrent episodes and improve quality of life. Recent studies have demonstrated the negative impact of MHE on quality of life and clinical outcomes. In light of all this, we emphasize the importance of screening and treating MHE in patients with liver cirrhosis, particularly through a multidisciplinary team approach.

Probiotics for people with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a disorder of brain function as a result of liver failure or portosystemic shunt or both. Both hepatic encephalopathy (clinically overt) and minimal hepatic encephalopathy (not clinically overt) significantly impair patient's quality of life and daily functioning, and represent a significant burden on healthcare resources. Probiotics are live micro-organisms, which when administered in adequate amounts, may confer a health benefit on the host.

OBJECTIVES

To determine the beneficial and harmful effects of probiotics in any dosage, compared with placebo or no intervention, or with any other treatment for people with any grade of acute or chronic hepatic encephalopathy. This review did not consider the primary prophylaxis of hepatic encephalopathy.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, conference proceedings, reference lists of included trials, and the World Health Organization International Clinical Trials Registry Platform until June 2016.

SELECTION CRITERIA

We included randomised clinical trials that compared probiotics in any dosage with placebo or no intervention, or with any other treatment in people with hepatic encephalopathy.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. We conducted random-effects model meta-analysis due to obvious heterogeneity of participants and interventions. We defined a P value of 0.05 or less as significant. We expressed dichotomous outcomes as risk ratio (RR) and continuous outcomes as mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 21 trials with 1420 participants, of these, 14 were new trials. Fourteen trials compared a probiotic with placebo or no treatment, and seven trials compared a probiotic with lactulose. The trials used a variety of probiotics; the most commonly used group of probiotic was VSL#3, a proprietary name for a group of eight probiotics. Duration of administration ranged from 10 days to 180 days. Eight trials declared their funding source, of which six were independently funded and two were industry funded. The remaining 13 trials did not disclose their funding source. We classified 19 of the 21 trials at high risk of bias.We found no effect on all-cause mortality when probiotics were compared with placebo or no treatment (7 trials; 404 participants; RR 0.58, 95% CI 0.23 to 1.44; low-quality evidence). No-recovery (as measured by incomplete resolution of symptoms) was lower for participants treated with probiotic (10 trials; 574 participants; RR 0.67, 95% CI 0.56 to 0.79; moderate-quality evidence). Adverse events were lower for participants treated with probiotic than with no intervention when considering the development of overt hepatic encephalopathy (10 trials; 585 participants; RR 0.29, 95% CI 0.16 to 0.51; low-quality evidence), but effects on hospitalisation and change of/or withdrawal from treatment were uncertain (hospitalisation: 3 trials, 163 participants; RR 0.67, 95% CI 0.11 to 4.00; very low-quality evidence; change of/or withdrawal from treatment: 9 trials, 551 participants; RR 0.70, 95% CI 0.46 to 1.07; very low-quality evidence). Probiotics may slightly improve quality of life compared with no intervention (3 trials; 115 participants; results not meta-analysed; low-quality evidence). Plasma ammonia concentration was lower for participants treated with probiotic (10 trials; 705 participants; MD -8.29 μmol/L, 95% CI -13.17 to -3.41; low-quality evidence). There were no reports of septicaemia attributable to probiotic in any trial.When probiotics were compared with lactulose, the effects on all-cause mortality were uncertain (2 trials; 200 participants; RR 5.00, 95% CI 0.25 to 102.00; very low-quality evidence); lack of recovery (7 trials; 430 participants; RR 1.01, 95% CI 0.85 to 1.21; very low-quality evidence); adverse events considering the development of overt hepatic encephalopathy (6 trials; 420 participants; RR 1.17, 95% CI 0.63 to 2.17; very low-quality evidence); hospitalisation (1 trial; 80 participants; RR 0.33, 95% CI 0.04 to 3.07; very low-quality evidence); intolerance leading to discontinuation (3 trials; 220 participants; RR 0.35, 95% CI 0.08 to 1.43; very low-quality evidence); change of/or withdrawal from treatment (7 trials; 490 participants; RR 1.27, 95% CI 0.88 to 1.82; very low-quality evidence); quality of life (results not meta-analysed; 1 trial; 69 participants); and plasma ammonia concentration overall (6 trials; 325 participants; MD -2.93 μmol/L, 95% CI -9.36 to 3.50; very low-quality evidence). There were no reports of septicaemia attributable to probiotic in any trial.

AUTHORS' CONCLUSIONS

The majority of included trials suffered from a high risk of systematic error ('bias') and a high risk of random error ('play of chance'). Accordingly, we consider the evidence to be of low quality. Compared with placebo or no intervention, probiotics probably improve recovery and may lead to improvements in the development of overt hepatic encephalopathy, quality of life, and plasma ammonia concentrations, but probiotics may lead to little or no difference in mortality. Whether probiotics are better than lactulose for hepatic encephalopathy is uncertain because the quality of the available evidence is very low. High-quality randomised clinical trials with standardised outcome collection and data reporting are needed to further clarify the true efficacy of probiotics.

Clinical science workshop: targeting the gut-liver-brain axis

A clinical science workshop was held at the ISHEN meeting in London on Friday 11th September 2014 with the aim of thrashing out how we might translate what we know about the central role of the gut-liver-brain axis into targets which we can use in the treatment of hepatic encephalopathy (HE). This review summarises the integral role that inter-organ ammonia metabolism plays in the pathogenesis of HE with specific discussion of the roles that the small and large intestine, liver, brain, kidney and muscle assume in ammonia and glutamine metabolism. Most recently, the salivary and gut microbiome have been shown to underpin the pathophysiological changes which culminate in HE and patients with advanced cirrhosis present with enteric dysbiosis with small bowel bacterial overgrowth and translocation of bacteria and their products across a leaky gut epithelial barrier. Resident macrophages within the liver are able to sense bacterial degradation products initiating a pro-inflammatory response within the hepatic parenchyma and release of cytokines such as tumour necrosis factor alpha (TNF-α) and interleukin-8 into the systemic circulation. The endotoxemia and systemic inflammatory response that are generated predispose both to the development of infection as well as the manifestation of covert and overt HE. Co-morbidities such as diabetes and insulin resistance, which commonly accompany cirrhosis, may promote slow gut transit, promote bacterial overgrowth and increase glutaminase activity and may need to be acknowledged in HE risk stratification assessments and therapeutic regimens. Therapies are discussed which target ammonia production, utilisation or excretion at an individual organ level, or which reduce systemic inflammation and endotoxemia which are known to exacerbate the cerebral effects of ammonia in HE. The ideal therapeutic strategy would be to use an agent that can reduce hyperammonemia and reduce systemic inflammation or perhaps to adopt a combination of therapies that can address both.

Probiotics in management of hepatic encephalopathy

Gut microflora leads to production of ammonia and endotoxins which play important role in the pathogenesis of hepatic encephalopathy (HE). There is relationship between HE and absorption of nitrogenous substances from the intestines. Probiotics play a role in treatment of HE by causing alterations in gut flora by decreasing the counts of pathogen bacteria, intestinal mucosal acidification, decrease in production and absorption of ammonia, alterations in permeability of gut, decreased endotoxin levels and changes in production of short chain fatty acids. Role of gut microbiota using prebiotics, probiotics and synbiotics have been evaluated in the management of minimal hepatic encephalopathy (MHE), overt HE and prevention of HE. Many studies have shown efficacy of probiotics in reduction of blood ammonia levels, treatment of MHE and prevention of HE. However these trials have problems like inclusion of small number of patients, short treatment durations, variability in HE/MHE related outcomes utilized and high bias risk, errors of systematic and random types. Systematic reviews also have shown different results with one systematic review showing clinical benefits whereas another concluded that probiotics do not have any role in treatment of MHE or HE. Also practical questions on optimal dose, ideal combination of organisms, and duration of treatment and persistence of benefits on long term follow-up are still to be clarified. At present, there are no recommendations for use of probiotics in patients with HE.

Gut Microbiota and the Liver: A Tale of 2 Cities: A Narrative View in 2 Acts

Microbes are mostly important for the digestion of food, the absorption of some micronutrients, and the production of vitamins. The microbiota stimulates lymphoid structures in the gastrointestinal mucosa and decrease pathogens by competing for nutrients and space. Bacterial translocation is defined as the escape of gut bacteria and their products through the intestinal mucosa to the outside of the intestine as portovenous or systemic circulation. This is induced by a leaky gut barrier. There is evidence for a role of intestinal permeability in the pathogenesis of nonalcoholic fatty liver disease. In the liver, bacterial products can bind to their specific pathogen recognition receptors on parenchymal and nonparenchymal cells, producing an inflammatory response and enhancing disease progression. When binding, bacterial products bind to their receptors, initiating intracellular signalling and inducing an inflammatory cascade, thus accelerating liver cell damage and fibrosis. However, the liver can also increase gut permeability, producing proinflammatory cytokines, and reversing them into the blood stream. Modification of the gut microbiota could lead to benefit in patients with liver disease. Nonabsorbable antibiotics (rifaximin) prevent and relieve overt encephalopathy. Probiotics alone are not capable of turning back overt encephalopathy, but could prevent its development. There is some evidence that probiotics could relent the progression of nonalcoholic liver disease, and possibly reverse steatosis. Antibiotics, such as fluoroquinolones, reduce the risk of development of the first episode of spontaneous bacterial peritonitis and mortality in cirrhotic patients.

Probiotics are helpful in hepatic encephalopathy: a meta-analysis of randomized trials

BACKGROUND

Hepatic encephalopathy (HE) is a major complication of cirrhosis and is associated with decreased survival and increased health care utilization.

AIM

The aim of this study was to evaluate the efficacy of probiotics in the management minimal hepatic encephalopathy HE (MHE) and overt HE (OHE) in comparison to no treatment/placebo and lactulose.

METHODS

The main outcomes measured were mortality, improvement in MHE, progression to OHE in patients with MHE and hospitalization. We calculated odds ratios (OR) with 95% confidence intervals (CI). Study heterogeneity was assessed using the I(2) statistic.

RESULTS

Fourteen studies totalling 1152 patients were included in the analysis. The use of probiotics had no impact on the overall mortality when compared to either lactulose (OR: 1.07, 95% CI: 0.47-2.44, P = 0.88) or no treatment/placebo (OR: 0.69, 95% CI: 0.42-1.14, P = 0.15). When probiotics was compared to no treatment/placebo, it was associated with a significant improvement in MHE (OR: 3.91, 95% CI: 2.25-6.80, P < 0.00001), decreased hospitalization rates (OR: 0.53, 95% CI: 0.33-0.86, P = 0.01) and decreased progression to overt hepatic encephalopathy (OR: 0.40, 95% CI: 0.26-0.60, P < 0.0001). However when compared to lactulose, probiotics did not show a significant difference in improvement of MHE (OR: 0.81, 95% CI: 0.52-1.27, P = 0.35), hospitalization rates (OR: 1.02, 95% CI: 0.52-1.99, P = 0.96) or progression to overt hepatic encephalopathy (OR: 1.24, 95% CI 0.73-2.10, P = 0.42).

CONCLUSIONS

Overall the use of probiotics was more effective in decreasing hospitalization rates, improving MHE and preventing progression to OHE in patients with underlying MHE than placebo, but similar to that seen with lactulose. The use of probiotics did not affect mortality rates.

A systematic review and meta-analysis of probiotics for the treatment of allergic rhinitis

BACKGROUND

Probiotics have proven beneficial in a number of immune-mediated and allergic diseases. Several human studies have evaluated the efficacy of probiotics in allergic rhinitis; however, evidence for their use has yet to be firmly established. The current systematic review seeks to synthesize the results of available randomized trials.

METHODS

In a systematic review and meta-analysis, the Medline, EMBASE, and Cochrane Library databases were reviewed and randomized controlled trials (RCTs) were extracted based on defined inclusion criteria. The effect of probiotics on Rhinitis Quality of Life (RQLQ) scores, Rhinitis Total Symptom Scores (RTSS), as well as total and antigen-specific serum immunoglobulin E (IgE) levels were evaluated by meta-analysis.

RESULTS

A total of 23 studies with 1919 patients were identified, including 21 double-blind RCTs and 2 randomized crossover studies. Multiple probiotic strains, study populations, and outcome measures were used in individual trials. Seventeen studies showed a significant clinical benefit from the use of probiotics in at least 1 outcome measure when compared to placebo, whereas 6 trials showed no benefit. Among the trials eligible for meta-analysis, the use of probiotics resulted in a significant improvement in RQLQ scores compared to placebo (standard mean difference [SMD] -2.23; p = 0.02). Probiotics had no effect on RTSS (SMD -0.36; p = 0.13) or total IgE levels (SMD 0.01; p = 0.94), although there was a trend toward a reduction in antigen-specific IgE (SMD 0.20; p = 0.06) in the placebo group compared to probiotic.

CONCLUSION

Probiotics may be beneficial in improving symptoms and quality of life in patients with allergic rhinitis; however, current evidence remains limited due to study heterogeneity and variable outcome measures. Additional high-quality studies are needed to establish appropriate recommendations.