Bifidobacterium longum with fructo-oligosaccharide (FOS) treatment in minimal hepatic encephalopathy: a randomized, double-blind, placebo-controlled study

The future of clinical trials of gut microbiome therapeutics in cirrhosis

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

Meta-analysis of probiotics efficacy in the treatment of minimum hepatic encephalopathy

OBJECTIVE

This study aims to systematically evaluate the efficacy of probiotics in treating minimum hepatic encephalopathy (MHE).

METHODS

A systematic search was conducted across three major databases: PubMed, China National Knowledge Infrastructure and Wanfang. The search period spanned from the inception of each database to 9 March 2023. The objective was to identify all randomised controlled trials (RCTs) examining the efficacy of probiotic preparations in treating MHE. The search terms included 'probiotics' along with other clinically relevant terms to comprehensively capture all pertinent studies.

RESULTS

A total of 18 RCTs were included. The meta-analysis showed that probiotic treatment outperformed control groups in reducing blood ammonia levels (standard mean difference [MD] = -2.68, 95% confidence interval [CI]: -3.90 to -1.46, p < .0001), improving the remission rate of MHE (risk ratio [RR] = 2.79, 95% CI: 1.23-6.35, p = .01) and lowering alanine aminotransferase levels (MD = -11.10, 95% CI: -16.17 to -6.03, p < .0001). It also significantly reduced the Model for End-Stage Liver Disease scores (MD = -2.55, 95% CI: -3.56 to -1.54, p < .00001) and the incidence of MHE (RR = .18, 95% CI: .09-.34, p < .00001).

CONCLUSION

Our study demonstrates that probiotics effectively improve blood ammonia levels, liver function and cognitive function in patients with MHE. They significantly enhance the remission rate of MHE and effectively reduce its incidence, providing solid new evidence for treating MHE with probiotics.

Fructooligosaccharides reverses hepatic vascular dysfunction and dysbiosis in rats with liver cirrhosis and portal hypertension

BACKGROUND

Portal hypertension leads to lethal complications in liver cirrhosis. Oxidative stress induced hepatic vascular dysfunction, which exaggerated vasoconstriction and increases hepatic vascular resistance (HVR). Gut dysbiosis further exacerbates portal hypertension. Fructooligosaccharides are prebiotics with potent antioxidant effect. This study aimed to evaluate the roles of fructooligosaccharides in portal hypertension-related vascular dysregulation and gut microbiome.

METHODS

Sprague-Dawley rats received bile duct ligation to induce cirrhosis or sham operation as controls. The rats then randomly received fructooligosaccharides or vehicle for 4 weeks. Experiments were performed on the 29th day after operations.

RESULTS

Fructooligosaccharides did not affect portal pressure. Interestingly, fructooligosaccharides significantly attenuated HVR (p = .03). Malondialdehyde, an oxidative stress marker, reduced significantly in the liver in fructooligosaccharides-treated group. In addition, superoxide dismutase and trolox equivalent antioxidant capacity increased in the treatment group. On the other hand, vasodilatation-related protein expressions, GTPCH and phospho-eNOS, enhanced significantly. Fructooligosaccharides had no adverse vasodilatation effects on splanchnic vascular system or porto-systemic collateral systems. Locomotor function was not affected by fructooligosaccharides. Faecal microbiota analysis showed that Negativicutes, Selenomonadales and Lactobacillus salivarius reduced in the fructooligosaccharides-treated group.

CONCLUSION

In conclusion, fructooligosaccharides attenuate hepatic vascular dysfunction in cirrhotic rats via at least partly, ameliorate of dysbiosis and oxidative stress.

Meta-analysis of randomized controlled trials of the effects of synbiotics, probiotics, or prebiotics in controlling glucose homeostasis in non-alcoholic fatty liver disease patients

Background: Probiotics, prebiotics, and synbiotics have been suggested as a possible therapy for non-alcoholic fatty liver disease (NAFLD). However, their efficacy in improving blood glucose levels in NAFLD patients remains uncertain. Objective: The aim of this study was to assess the effects of supplementation with probiotics, prebiotics, or synbiotics on fasting blood glucose (FBG) levels in NAFLD patients. Methods: We searched PubMed, Web of Science, and Google Scholar for relevant trials published up to March 2024. Out of 3369 identified studies, 24 randomized controlled trials (RCTs) were included. Results: Probiotic, prebiotic, or synbiotic supplementation substantially reduced FBG (n = 23; standard mean difference (SMD) = -0.17; 95% confidence interval (CI): -0.30, -0.03; P = 0.02), fasting insulin levels (n = 12; SMD = -0.28; 95% CI: -0.49, -0.07; P = 0.01), and homeostatic model assessment for insulin resistance (HOMA-IR; n = 14; SMD = -0.28; 95% CI: -0.47, -0.09; P = 0.004). However, glycosylated hemoglobin (HbA1c; n = 3; SMD = -0.17; 95% CI: -0.48, 0.13; P = 0.27) was not significantly affected. The FBG-decreasing effect diminished as the body mass index (BMI) of volunteers increased in the baseline. Additionally, the number of probiotic strains and geographic region were shown to significantly affect FBG levels. Conclusion: This meta-analysis indicates that supplementation with probiotics, prebiotics, or synbiotics may aid in controlling glucose homeostasis in patients with NAFLD.

Endogenous ethanol production in health and disease

The gut microbiome exerts metabolic actions on distal tissues and organs outside the intestine, partly through microbial metabolites that diffuse into the circulation. The disruption of gut homeostasis results in changes to microbial metabolites, and more than half of the variance in the plasma metabolome can be explained by the gut microbiome. Ethanol is a major microbial metabolite that is produced in the intestine of nearly all individuals; however, elevated ethanol production is associated with pathological conditions such as metabolic dysfunction-associated steatotic liver disease and auto-brewery syndrome, in which the liver's capacity to metabolize ethanol is surpassed. In this Review, we describe the mechanisms underlying excessive ethanol production in the gut and the role of ethanol catabolism in mediating pathogenic effects of ethanol on the liver and host metabolism. We conclude by discussing approaches to target excessive ethanol production by gut bacteria.

Microbiota and Gut-Liver Axis: An Unbreakable Bond?

The gut microbiota, amounting to approximately 100 trillion (1014) microbes represents a genetic repertoire that is bigger than the human genome itself. Evidence on bidirectional interplay between human and microbial genes is mounting. Microbiota probably play vital roles in diverse aspects of normal human metabolism, such as digestion, immune modulation, and gut endocrine function, as well as in the genesis and progression of many human diseases. Indeed, the gut microbiota has been most closely linked to various chronic ailments affecting the liver, although concrete scientific data are sparse. In this narrative review, we initially discuss the basic epidemiology of gut microbiota and the factors influencing their initial formation in the gut. Subsequently, we delve into the gut-liver axis and the evidence regarding the link between gut microbiota and the genesis or progression of various liver diseases. Finally, we summarise the recent research on plausible ways to modulate the gut microbiota to alter the natural history of liver disease.

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.

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.

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.

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.

Nutritional therapy for persistent cognitive impairment after resolution of overt hepatic encephalopathy in patients with cirrhosis: A double-blind randomized controlled trial

BACKGROUND AND AIM

Minimal hepatic encephalopathy (MHE) reflects cognitive impairment in patients with liver cirrhosis and is associated with poor prognosis. We assessed the effects of nutritional therapy on cognitive functions, health-related quality of life (HRQOL), anthropometry, endotoxins, and inflammatory markers in cirrhotic patients with MHE.

METHODS

In a double-blind randomized controlled trial, cirrhotic patients with MHE were randomized to nutritional therapy (group I: 30-35 kcal/kg/day and 1.0-1.5 g of protein/kg/day) and no nutritional therapy (group II: diet as patients were taking before) for 6 months. MHE was diagnosed based on psychometric hepatic encephalopathy score (PHES). Anthropometry, ammonia, endotoxins, inflammatory markers, myostatin, and HRQOL were assessed at baseline and after 6 months. Primary endpoints were improvement or worsening in MHE and HRQOL.

RESULTS

A total of 150 patients were randomized to group I (n = 75, age 46.3 ± 12.5 years, 58 men) and group II (n = 75, age 45.2 ± 9.3 years, 56 men). Baseline PHES (-8.16 ± 1.42 vs -8.24 ± 1.43; P = 0.54) was comparable in both groups. Reversal of MHE was higher in group I (73.2% vs 21.4%; P = 0.001) than group II. Improvement in PHES (Δ PHES 4.0 ± 0.60 vs -4.18 ± 0.40; P = 0.001), HRQOL (Δ Sickness Impact Profile 3.24 ± 3.63 vs 0.54 ± 3.58; P = 0.001), anthropometry, ammonia, endotoxins, cytokines, and myostatin levels was also significantly higher in group I than group II. Overt hepatic encephalopathy developed in 6 patients in group I and 13 in group II (P = 0.04).

CONCLUSIONS

Nutritional therapy is effective in treatment of MHE and associated with improvement in nutritional status, HRQOL, ammonia, endotoxins, inflammatory markers, and myostatin levels.

The Influence of Probiotic Supplementation on the Obesity Indexes, Neuroinflammatory and Oxidative Stress Markers, Gut Microbial Diversity, and Working Memory in Obese Thai Children

Obesity is a worldwide health problem with a complex interaction between gut microbiota and cognition. Several studies have demonstrated that probiotic treatments improve characteristics linked to obesity. The present study aimed to evaluate the effects of probiotic supplementation on the obesity indexes, inflammatory and oxidative stress markers, gut microbiota, and working memory in obese children. Ten obese children were assigned to receive the probiotics (8 × 109 CFU of Lactobacillus paracasei HII01 and Bifidobacterium animalis subsp. lactis) for 12 weeks. Demographic data were recorded. Urine and fecal samples were collected to evaluate biomarkers related to obesity and cognition. Behavioral working memory was assessed using the visual n-back test. Electroencephalography was employed to measure electrical activity during the visual n-back test. All parameters were evaluated at the baseline and after 12 weeks. The results revealed that probiotic supplementation significantly altered some gut microbial metabolites, gut microbiota, total antioxidant capacity, and neuroinflammatory markers. However, no significant changes were observed in the visual n-back test or electroencephalographic recordings after 12 weeks. In conclusion, the use of probiotics might be an alternative treatment that could improve the gut microbial ecosystem and microbial metabolites, as well as host antioxidant and neuroinflammation levels. The preliminary results indicated that further detailed prolonged studies are needed in order to determine the beneficial effects of the studied probiotics.

From-Toilet-to-Freezer: A Review on Requirements for an Automatic Protocol to Collect and Store Human Fecal Samples for Research Purposes

The composition, viability and metabolic functionality of intestinal microbiota play an important role in human health and disease. Studies on intestinal microbiota are often based on fecal samples, because these can be sampled in a non-invasive way, although procedures for sampling, processing and storage vary. This review presents factors to consider when developing an automated protocol for sampling, processing and storing fecal samples: donor inclusion criteria, urine-feces separation in smart toilets, homogenization, aliquoting, usage or type of buffer to dissolve and store fecal material, temperature and time for processing and storage and quality control. The lack of standardization and low-throughput of state-of-the-art fecal collection procedures promote a more automated protocol. Based on this review, an automated protocol is proposed. Fecal samples should be collected and immediately processed under anaerobic conditions at either room temperature (RT) for a maximum of 4 h or at 4 °C for no more than 24 h. Upon homogenization, preferably in the absence of added solvent to allow addition of a buffer of choice at a later stage, aliquots obtained should be stored at either -20 °C for up to a few months or -80 °C for a longer period-up to 2 years. Protocols for quality control should characterize microbial composition and viability as well as metabolic functionality.

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.

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.

Alterations of gut microbiome and effects of probiotic therapy in patients with liver cirrhosis: A systematic review and meta-analysis

BACKGROUND

Alterations in the gut microbiome usually occur in liver cirrhosis. Gut microbiome dysregulation damages the liver and accelerates the development of liver fibrosis. Probiotic treatment has gradually become a major method for improving the prognosis of liver cirrhosis and reducing its complications. However, alterations in the gut microbiome have revealed different results, and the therapeutic effects of various probiotics are inconsistent.

METHODS

We searched the PubMed, Medline, EMBASE, ScienceDirect, and Cochrane databases up to August 2022 and conducted a systematic review and meta-analysis of 17 relevant studies.

RESULTS

The counts of Enterobacter (standardized mean difference [SMD] -1.79, 95% confidence interval [CI]: -3.08 to -0.49) and Enterococcus (SMD -1.41, 95% CI: -2.26 to -0.55) increased significantly in patients with cirrhosis, while the counts of Lactobacillus (SMD 0.63, 95% CI: 0.12-1.15) and Bifidobacterium (SMD 0.44, 95% CI: 0.12-0.77) decreased significantly. Blood ammonia (weighted mean difference [WMD] 14.61, 95% CI: 7.84-21.37) and the incidence of hepatic encephalopathy (WMD 0.40, 95% CI: 0.27-0.61) were significantly decreased in the probiotic group. As for mortality (MD 0.75, 95% CI: 0.48-1.16) and the incidence of spontaneous bacterial peritonitis (WMD -0.02, 95% CI: -0.07 to 0.03), no significant differences were found between the probiotic and placebo groups.

CONCLUSION

In summary, the gut microbiome in cirrhosis manifests as decreased counts of Lactobacillus and Bifidobacterium and increased counts of Enterobacter and Enterococcus. Targeted supplementation of probiotics in cirrhosis, including Lactobacillus combined with Bifidobacterium or Bifidobacterium alone, can reduce blood ammonia and the incidence of hepatic encephalopathy. The effect is similar to that of lactulose, but it has no obvious effect on mortality and spontaneous bacterial peritonitis.

Minimal Hepatic Encephalopathy Affects Daily Life of Cirrhotic Patients: A Viewpoint on Clinical Consequences and Therapeutic Opportunities

Minimal hepatic encephalopathy (MHE) is a frequent complication of hepatic encephalopathy (HE) and can affect up to 80% of patients with liver cirrhosis. It is characterized by the lack of obvious clinical signs and the presence of alterations detectable using psychometric or electrophysiological testing focused on attention, working memory, psychomotor speed and visuospatial ability. Ideally, each patient should be tested for this condition because, despite the absence of symptoms, it has severe repercussions on daily life activities. It may be responsible for an inability to drive, sleep disturbances, risk of falls and inability to work. Some studies have highlighted its prognostically unfavorable role on mortality and risk of "overt" HE (OHE). Finally, MHE severely affects the lives of patients and caregivers, altering their quality of life and their socioeconomic status. Several treatments have been proposed for MHE treatment, including non-absorbable disaccharides, poorly absorbable antibiotics, such as rifaximin, probiotics and branched-chain amino acids, with promising results. For this reason, early diagnosis and intervention with appropriate measures is essential, with the aim of improving both performance on psychometric tests, as well as clinical aspects related to this condition.

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 promising role of probiotics/prebiotics/synbiotics in energy metabolism biomarkers in patients with NAFLD: A systematic review and meta-analysis

Background

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease with a high prevalence worldwide, seriously harming human health, and its pathogenesis remains unclear. In recent years, increasing evidence has indicated that intestinal microbiota plays an important role in the occurrence and development of NAFLD. The regulation method of probiotics/prebiotics/synbiotics can alter the intestinal microbiota and has been suggested as an option in the treatment of NAFLD.

Methods

Five databases of PubMed, Embase, the Cochrane Library, clinicaltrails.gov, and China National Knowledge Infrastructure were searched initially, and then the eligible studies were screened. Finally, the data of included studieswere extracted, combined and analyzed

Results

A total of 29 randomized controlled trials involving 2,110 patients were included in this study. The results showed that using probiotics/prebiotics/synbiotics in the intervention group could reduce the levels of glucose (SMD = −0.23, 95% CI [−0.45, −0.01], P = 0.04), HOMA-IR (SMD = −0.47, 95% CI [−0.63, −0.31], P < 0.00001) and insulin (SMD = −0.46, 95% CI [−0.76, −0.16], P = 0.002) in sugar metabolism; in terms of lipid metabolism, the levels of TC (SMD = −0.62, 95%CI [−0.87, −0.36], P < 0.00001), and LDL-C (SMD = −0.57, 95%CI [−0.85, −0.28], P < 0.00001) were decreased; and the level of ALB was decreased in protein metabolism (SMD = −0.34, 95%CI [−0.61, −0.06], P = 0.02).

Conclusions

Based on the current evidence, probiotics/prebiotics/synbiotics may improve energy metabolism biomarkers in the NAFLD population, but these effects still need to be confirmed by further research.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/#aboutpage.

The Role of Gut-Derived Lipopolysaccharides and the Intestinal Barrier in Fatty Liver Diseases

BACKGROUND

Hepatosteatosis is the earliest stage in the pathogenesis of nonalcoholic fatty (NAFLD) and alcoholic liver disease (ALD). As NAFLD is affecting 10-24% of the general population and approximately 70% of obese patients, it carries a large economic burden and is becoming a major reason for liver transplantation worldwide. ALD is a major cause of morbidity and mortality causing 50% of liver cirrhosis and 10% of liver cancer related death. Increasing evidence has accumulated that gut-derived factors play a crucial role in the development and progression of chronic liver diseases.

METHODS

A selective literature search was conducted in Medline and PubMed, using the terms "nonalcoholic fatty liver disease," "alcoholic liver disease," "lipopolysaccharide," "gut barrier," and "microbiome."

RESULTS

Gut dysbiosis and gut barrier dysfunction both contribute to chronic liver disease by abnormal regulation of the gut-liver axis. Thereby, gut-derived lipopolysaccharides (LPS) are a key factor in inducing the inflammatory response of liver tissue. The review further underlines that endotoxemia is observed in both NAFLD and ALD patients. LPS plays an important role in conducting liver damage through the LPS-TLR4 signaling pathway. Treatments targeting the gut microbiome and the gut barrier such as fecal microbiota transplantation (FMT), probiotics, prebiotics, synbiotics, and intestinal alkaline phosphatase (IAP) represent potential treatment modalities for NAFLD and ALD.

CONCLUSIONS

The gut-liver axis plays an important role in the development of liver disease. Treatments targeting the gut microbiome and the gut barrier have shown beneficial effects in attenuating liver inflammation and need to be further investigated.

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.

Current approach to treatment of minimal hepatic encephalopathy in patients with liver cirrhosis

Minimal hepatic encephalopathy (MHE) corresponds to the earliest stage of hepatic encephalopathy (HE). MHE does not present clinically detectable neurological-psychiatric abnormalities but is characterized by imperceptible neurocognitive alterations detected during routine clinical examination via neuropsychological or psychometrical tests. MHE may affect daily activities and reduce job performance and quality of life. MHE can increase the risk of accidents and may develop into overt encephalopathy, worsening the prognosis of patients with liver cirrhosis. Despite a lack of consensus on the therapeutic indication, interest in finding novel strategies for prevention or reversion has led to numerous clinical trials; their results are the main objective of this review. Many studies address the treatment of MHE, which is mainly based on the strategies and previous management of overt HE. Current alternatives for the management of MHE include measures to maintain nutritional status while avoiding sarcopenia, and manipulation of intestinal microbiota with non-absorbable disaccharides such as lactulose, antibiotics such as rifaximin, and administration of different probiotics. This review analyzes the results of clinical studies that evaluated the effects of different treatments for MHE.

Medical Application of Substances Derived from Non-Pathogenic Fungi Aspergillus oryzae and A. luchuensis-Containing Koji

Although most fungi cause pathogenicity toward human beings, dynasties of the East Asian region have domesticated and utilized specific fungi for medical applications. The Japanese dynasty and nation have domesticated and utilized koji fermented with non-pathogenic fungus Aspergillus oryzae for more than 1300 years. Recent research has elucidated that koji contains medicinal substances such as Taka-diastase, acid protease, koji glycosylceramide, kojic acid, oligosaccharides, ethyl-α-d-glucoside, ferulic acid, ergothioneine, pyroglutamyl leucine, pyranonigrin A, resistant proteins, deferriferrichrysin, polyamines, Bifidobacterium-stimulating peptides, angiotensin I-converting enzyme inhibitor peptides, 14-dehydroergosterol, beta-glucan, biotin, and citric acid. This review introduces potential medical applications of such medicinal substances to hyperlipidemia, diabetes, hypertension, cardiovascular and cognitive diseases, chronic inflammation, epidermal permeability barrier disruption, coronavirus disease 2019 (COVID-19), and anti-cancer therapy.

Bifidobacterium longum W11: Uniqueness and individual or combined clinical use in association with rifaximin

BACKGROUNDS & AIMS

Strains belonging to bifidobacteria have been documented as being helpful in adults with intestinal dysbiosis conditions, like those related to irritable bowel syndrome (IBS). This review aims to present the most relevant evidence regarding the efficacy of Bifidobacterium longum W11, a Bifidobacterium used in clinical settings for conditions such as IBS and inflammatory bowel disease.

METHODS

The following electronic databases were systematically searched up to August 2020: MEDLINE (via PubMed), EMBASE, Cochrane Central Database of Controlled Trials (via CENTRAL), Google Scholar, and Clinicaltrials.gov.

RESULTS

Data arising from pooled analysis, 7 in vitro/pharmacological studies, 7 clinical trials including 1 randomized, double-blind and placebo-controlled, showed that the probiotic strain B. longum W11 has been extensively studied for its efficacy in subjects with IBS with constipation, leading to a significant reduction in symptoms. In particular, its role in alleviating constipation was also confirmed in subjects for whom a low-calorie weight-loss diet led to the slowing down of gut motility. The probiotic characteristics of B. longum W11 were further demonstrated in the treatment of minimal hepatic encephalopathy and hepatic disease. The most remarkable trait of B. longum W11 is its non-transmissible antibiotic resistance, due to a nucleotide polymorphism mutation in the rpoB gene, making it resistant to antibiotics of the rifampicin group, including rifaximin. The co-administration of B. longum W11 and rifaximin in patients with symptomatic uncomplicated diverticular disease brought about a further significant improvement in the clinical condition compared to patients treated with rifaximin alone. B. longum W11 is a probiotic which could synergize with rifaximin as an adjuvant to antibiotic treatment.

CONCLUSIONS

Taken altogether these findings demonstrate the clinical role of the strain W11 both in some functional and in some inflammatory bowel diseases.

Manipulation of microbiota with probiotics as an alternative for treatment of hepatic encephalopathy

Hepatic encephalopathy is a cerebral alteration mainly caused by hepatic insufficiency or portosystemic shunt. It ranges from minimal neurologic manifestations to coma in its overt stage. The multifactorial pathophysiology of hepatic encephalopathy has rendered numerous treatment alternatives, among which the modification of dysbiosis and hyperammonemia are currently considered to be effective, not only clinically, but also regarding cost. Recent work has developed knowledge of probiotics in different clinical settings including the relationship of the gut microenvironment to liver cirrhosis. The aim of this review was to analyze the results of clinical trials on the effect of different probiotics on hepatic encephalopathy.

The role of the gut microbiome in chronic liver disease: the clinical evidence revised

Recent research has suggested a role for the intestinal microbiota in the pathogenesis and potential treatment of a wide range of liver diseases. The intestinal microbiota and bacterial products may contribute to the development of liver diseases through multiple mechanisms including increased intestinal permeability, chronic systemic inflammation, production of short-chain fatty acids and changes in metabolism. This suggests a potential role for pre-, pro- and synbiotic products in the prevention or treatment of some liver diseases. In addition, there is emerging evidence on the effects of faecal microbial transplant. Herein, we discuss the relationship between the intestinal microbiota and liver diseases, as well as reviewing intestinal microbiota-based treatment options that are currently being investigated.

Dietary approach and gut microbiota modulation for chronic hepatic encephalopathy in cirrhosis

Hepatic encephalopathy (HE) is a common and serious neuropsychiatric complication of cirrhosis, acute liver failure, and porto-systemic shunting. HE largely contributes to the morbidity of patients with liver disease, severely affecting the quality of life of both patients and their relatives and being associated with poor prognosis. Its presentation is largely variable, manifesting with a broad spectrum of cognitive abnormalities ranging from subtle cognitive impairment to coma. The pathogenesis of HE is complex and has historically been linked with hyperammonemia. However, in the last years, it has become evident that the interplay of multiple actors, such as intestinal dysbiosis, gut hyperpermeability, and neuroinflammation, is of crucial importance in its genesis. Therefore, HE can be considered a result of a 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 non-absorbable disaccharides, non-absorbable antibiotics, probiotics, prebiotics, and fecal microbiota transplantation. In this context dietary modifications, by modulating the intestinal milieu, can also provide significant benefit to cirrhotic patients with HE. This review will provide a comprehensive insight into the mechanisms responsible for gut-liver-brain axis dysregulation leading to HE in cirrhosis. Furthermore, it will explore the currently available therapies and the most promising future treatments for the management of patients with HE, with a special focus on the dietary approach.

The gut microbiota influences anticancer immunosurveillance and general health

Discoveries made in the past 5 years indicate that the composition of the intestinal microbiota has a major influence on the effectiveness of anticancer immunosurveillance and thereby contributes to the therapeutic activity of immune-checkpoint inhibitors that target cytotoxic T lymphocyte protein 4 (CTLA-4) or the programmed cell death protein 1 (PD-1)-programmed cell death 1 ligand 1 (PD-L1) axis, as well as the activity of immunogenic chemotherapies. Herein, we highlight some of the bacteria, such as Akkermansia muciniphila, Bacteroides fragilis, Bifidobacterium spp. and Faecalibacterium spp., that have been associated with favourable anticancer immune responses in both preclinical tumour models and patients with cancer. Importantly, these bacteria also seem to have a positive influence on general health, thus reducing the incidence of metabolic disorders and a wide range of chronic inflammatory pathologies. We surmise that a diverse and propitious microbial ecosystem favours organismal homeostasis, particularly at the level of the cancer-immune dialogue.

The role of gut microbiota in liver disease development and treatment

Liver cancer is the sixth most common cancer worldwide, and the third most common cause of cancer-related death. Hepatocellular carcinoma (HCC), which accounts for more than 90% of primary liver cancers, is an important public health problem. In addition to cirrhosis caused by hepatitis B viral (HBV) or hepatitis C viral (HCV) infection, non-alcoholic fatty liver disease (NAFLD) is becoming a major risk factor for liver cancer because of the prevalence of obesity. Non-alcoholic steatohepatitis (NASH) will likely become the leading indication for liver transplantation in the future. It is well recognized that gut microbiota is a key environmental factor in the pathogenesis of liver disease and cancer. The interplay between gut microbiota and liver disease has been investigated in animal and clinical studies. In this article, we summarize the roles of gut microbiota in the development of liver disease as well as gut microbiota-targeted therapies.

How to Design a Multicenter Clinical Trial in Hepatic Encephalopathy

The design of clinical trials on Hepatic Encephalopathy (HE) is not an easy task, in fact there are several issues related to the performance of clinical trials in HE that have impeded progress in the field, mainly because most of the studies on HE therapy were performed before the era of rigorous Randomized Controlled Trials (RCTs). In this review we discuss the major problems affecting previously published trials on HE treatments aiming to provide evidences, suggestions and indications to prepare well designed RCTs in three different settings: (1) management of hospitalized patients with episodic HE; (2) secondary prophylaxis in patients following an episode of HE; and (3) management of minimal/covert HE.

Quality of life in patients with minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) represents the mildest type of hepatic encephalopathy (HE). This condition alters the performance of psychometric tests by impairing attention, working memory, psychomotor speed, and visuospatial ability, as well as electrophysiological and other functional brain measures. MHE is a frequent complication of liver disease, affecting up to 80% of tested patients, depending of the diagnostic tools used for the diagnosis. MHE is related to falls, to an impairment in fitness to drive and the development of overt HE, MHE severely affects the lives of patients and caregivers by altering their quality of life (QoL) and their socioeconomic status. MHE is detected in clinically asymptomatic patients through appropriate psychometric tests and neurophysiological methods which highlight neuropsychological alterations such as video-spatial orientation deficits, attention disorders, memory, reaction times, electroencephalogram slowing, prolongation of latency evoked cognitive potentials and reduction in the critical flicker frequency. Several treatments have been proposed for MHE treatment such as non-absorbable disaccharides, poorly absorbable antibiotics such rifaximin, probiotics and branched chain amino acids. However, because of the multiple diagnosis methods, the various endpoints of treatment trials and the variety of agents used in trials, to date the treatment of MHE is not routinely recommended apart from on a case-by-case basis. Aim of this review is analyze the burden of MHE on QoL of patients and provide a brief summary of therapeutic approaches.

Role of probiotics in the treatment of minimal hepatic encephalopathy in patients with HBV-induced liver cirrhosis

Objective This study was performed to investigate the role of probiotics ( Clostridium butyricum combined with Bifidobacterium infantis) in the treatment of minimal hepatic encephalopathy (MHE) in patients with hepatitis B virus (HBV)-induced liver cirrhosis. Methods Sixty-seven consecutive patients with HBV-induced cirrhosis without overt hepatic encephalopathy were screened using the number connection test and digit symbol test. The patients were randomized to receive probiotics (n = 30) or no probiotics (n = 37) for 3 months. At the end of the trial, changes in cognition, intestinal microbiota, venous ammonia, and intestinal mucosal barriers were analyzed using recommended systems biology techniques. Results The patients' cognition was significantly improved after probiotic treatment. The predominant bacteria ( Clostridium cluster I and Bifidobacterium) were significantly enriched in the probiotics-treated group, while Enterococcus and Enterobacteriaceae were significantly decreased. Probiotic treatment was also associated with an obvious reduction in venous ammonia. Additionally, the parameters of the intestinal mucosal barrier were obviously improved after probiotic treatment, which might have contributed to the improved cognition and the decreased ammonia levels. Conclusion Treatment with probiotics containing C. butyricum and B. infantis represents a new adjuvant therapy for the management of MHE in patients with HBV-induced cirrhosis.

Does Severity of Alzheimer's Disease Contribute to Its Responsiveness to Modifying Gut Microbiota? A Double Blind Clinical Trial

Alzheimer's disease (AD) is associated with cognitive dysfunction. Evidence indicates that gut microbiota is altered in the AD and, hence, modifying the gut flora may affect the disease. In the previous clinical research we evaluated the effect of a probiotic combination on the cognitive abilities of AD patients. Since, in addition to pathological disorders, the AD is associated with changes in oxidant/antioxidant and inflammatory/anti-inflammatory biomarkers, the present work was designed to evaluate responsiveness of the inflammatory and oxidative biomarkers to the probiotic treatment. The control (CON) and probiotic (PRO) AD patients were treated for 12 weeks by the placebo and probiotic supplementation, respectively. The patients were cognitively assessed by Test Your Memory (TYM = 50 scores). Also serum concentrations of nitric oxide (NO), glutathione (GSH), total antioxidant capacity (TAC), malondialdehyde (MDA), 8-hydroxy-2′ -deoxyguanosine (8-OHdG) and cytokines (TNF-a, IL-6, and IL-10) were measured. The cognitive test and the serum biomarkers were assessed pre- and post-treatment. According to TYM test 83.5% of the patients showed severe AD. The CON (12.86% ± 8.33) and PRO (−9.35% ± 16.83) groups not differently scored the cognitive test. Not pronounced change percent was found in the serum level of TNF-α (1.67% ± 1.33 vs. −0.15% ± 0.27), IL-6 (0.35% ± 0.17 vs. 2.18% ± 0.15), IL-10 (0.05% ± 0.10 vs. −0.70% ± 0.73), TAC (0.07% ± 0.07 and −0.06% ± 0.03), GSH (0.08% ± 0.05 and 0.04% ± 0.03) NO (0.11% ± 0.06 and 0.05% ± 0.09), MDA (−0.11% ± 0.03 and −0.17% ± 0.03), 8-OHdG (43.25% ± 3.01 and 42.70% ± 3.27) in the CON and PRO groups, respectively. We concluded that the cognitive and biochemical indications in the patients with severe AD are insensitive to the probiotic supplementation. Therefore, in addition to formulation and dosage of probiotic bacteria, severity of disease and time of administration deeply affects results of treatment.

Probiotics in Gastroenterology: How Pro Is the Evidence in Adults?

Probiotic usage has become popular with both medical practitioners and the community in general; patients commonly seek advice regarding what, if any, such preparation would be useful for their own diseases. Since such advice should be evidence-based, identified randomized clinical trials (RCTs) for a number of gastrointestinal conditions were reviewed; the data were organized by individual probiotic genera/species. Only trials in adults were considered. Most of the identified RCTs were small and low-quality, so any conclusions to be drawn will be limited at least by methodologic problems. Using the GRADE system to consider the reliability of the evidence generated from these RCTs, it did appear that the use of fecal microbial transplantation to treat recurrent Clostridium difficile infection is well justified. Given the methodologic issues, there was moderately good evidence for preventing antibiotic-associated diarrhea with Lactobacillus, Bifidobacterium, Streptococcus, or Saccharomyces boulardii and for using Lactobacillus, Bifidobacterium, or Saccharomyces as adjunct therapy in the treatment of Helicobacter pylori. There were other conditions for which some supportive evidence was available. These conditions include VSL#3 for maintaining remissions in patients with pouchitis or treating active ulcerative colitis (UC), fecal microbial transplantation for treating active UC, Bifidobacterium for treating patients with UC in remission, Lactobacillus in patients with painful diverticulosis, a variety of probiotics (Lactobacillus, Bifidobacterium, Streptococcus, or VSL#3) in patients with minimal hepatic encephalopathy, and providing synbiotics to patients postoperatively after liver transplantation. Unfortunately, other limitations in the evidence made it very likely that future research will have an effect on the estimated benefit; these interventions cannot yet be recommended for routine use.

Combining amplicon sequencing and metabolomics in cirrhotic patients highlights distinctive microbiota features involved in bacterial translocation, systemic inflammation and hepatic encephalopathy

In liver cirrhosis (LC), impaired intestinal functions lead to dysbiosis and possible bacterial translocation (BT). Bacteria or their byproducts within the bloodstream can thus play a role in systemic inflammation and hepatic encephalopathy (HE). We combined 16S sequencing, NMR metabolomics and network analysis to describe the interrelationships of members of the microbiota in LC biopsies, faeces, peripheral/portal blood and faecal metabolites with clinical parameters. LC faeces and biopsies showed marked dysbiosis with a heightened proportion of Enterobacteriaceae. Our approach showed impaired faecal bacterial metabolism of short-chain fatty acids (SCFAs) and carbon/methane sources in LC, along with an enhanced stress-related response. Sixteen species, mainly belonging to the Proteobacteria phylum, were shared between LC peripheral and portal blood and were functionally linked to iron metabolism. Faecal Enterobacteriaceae and trimethylamine were positively correlated with blood proinflammatory cytokines, while Ruminococcaceae and SCFAs played a protective role. Within the peripheral blood and faeces, certain species (Stenotrophomonas pavanii, Methylobacterium extorquens) and metabolites (methanol, threonine) were positively related to HE. Cirrhotic patients thus harbour a 'functional dysbiosis' in the faeces and peripheral/portal blood, with specific keystone species and metabolites related to clinical markers of systemic inflammation and HE.

Hepatic encephalopathy: current challenges and future prospects

Hepatic encephalopathy (HE) is a common complication of liver dysfunction, including acute liver failure and liver cirrhosis. HE presents as a spectrum of neuropsychiatric symptoms ranging from subtle fluctuating cognitive impairment to coma. It is a significant contributor of morbidity in patients with liver disease. HE is observed in acute liver failure, liver bypass procedures, for example, shunt surgry and transjugular intrahepatic portosystemic shunt, and cirrhosis. These are classified as Type A, B and C HE, respectively. HE can also be classified according to whether its presence is overt or covert. The pathogenesis is linked with ammonia and glutamine production, and treatment is based on mechanisms to reduce the formation and/or removal of these compounds. There is no specific diagnostic test for HE, and diagnosis is based on clinical suspicion, excluding other causes and use of clinical tests that may support its diagnosis. Many tests are used in trials and experimentally, but have not yet gained universal acceptance. This review focuses on the definitions, pathogenesis and treatment of HE. Consideration will be given to existing treatment, including avoidance of precipitating factors and novel therapies such as prebiotics, probiotics, antibiotics, laxatives, branched-chain amino acids, shunt embolization and the importance of considering liver transplant in appropriate cases.

The burden of minimal hepatic encephalopathy: from diagnosis to therapeutic strategies

Minimal hepatic encephalopathy (MHE) is the mildest form of hepatic encephalopathy (HE). It affects the performance of psychometric tests focused on attention, working memory, psychomotor speed, and visuospatial ability, as well as electrophysiological and other functional brain measures. MHE is a frequent complication of liver disease, affecting up to 80% of tested patients. By being related to falls, an impairment in fitness to drive and the development of overt HE, MHE severely affects the lives of patients and caregivers by altering their quality of life and their socioeconomic status. MHE is detected in clinically asymptomatic patients using appropriate psychometric tests and neurophysiological methods that highlight neuropsychological alterations, such as video-spatial orientation deficits, attention disorders, memory, reaction times, electroencephalogram slowing, prolongation of latency-evoked cognitive potentials, and reduction in the critical flicker frequency. Several treatments have been proposed for MHE treatment, including non-absorbable disaccharides, poorly absorbable antibiotics such as rifaximin, probiotics and branched-chain amino acids. However, because of the multiple diagnosis methods, the various endpoints of treatment trials and the variety of agents used in trials, the treatment of MHE is not currently recommended as routine, but only on a case-by-case basis.

Effect of probiotic treatment on cirrhotic patients with minimal hepatic encephalopathy: A meta-analysis

BACKGROUND

Minimal hepatic encephalopathy (MHE) is an early and reversible form of hepatic encephalopathy. The documentations on the treatment with probiotics are inconsistent. The present meta-analysis was to verify the role of probiotics in the treatment of cirrhotic patients with MHE.

DATA SOURCES

Seven electronic databases were searched for relevant randomized controlled trials (RCTs) published until July 2015. The effects of probiotics on serum ammonia, endotoxin, and MHE were evaluated.

RESULTS

A total of 14 RCTs (combined n = 1132) were included in the meta-analysis. When probiotics were compared to placebo or no treatment, probiotics were more likely to reduce values in the number connection test (NCT; week 4: MD = -30.25, 95% CI: -49.85 to -10.66), improve MHE (week 4: OR = 0.18, 95% CI: 0.07 to 0.47; week 12: OR = 0.15, 95% CI: 0.07 to 0.32), and prevent overt HE progression (week 4: OR = 0.22, 95% CI: 0.07 to 0.67) in patients with liver cirrhosis. When probiotics was compared to lactulose, probiotics tended to reduce serum ammonia levels (week 4: MD = -0.33 µmol/L, 95% CI: -5.39 to 4.74; week 8: MD = 6.22 µmol/L, 95% CI: -24.04 to 36.48), decrease NCT (week 8: MD = 3.93, 95% CI: -0.72 to 8.58), improve MHE (week 4: OR = 0.93, 95% CI: 0.45 to 1.91; week 12: OR = 0.73, 95% CI: 0.35 to 1.51) and prevent the development of overt HE (week 4: OR = 0.96, 95% CI: 0.17 to 5.44; week 12: OR = 2.7, 95% CI: 0.50 to 14.64) in patients with liver cirrhosis. However, lactulose appears to be more effective in reducing NCT values as compared to probiotics (week 4: MD = 6.7, 95% CI: 0.58 to 12.82).

CONCLUSION

Probiotics can decrease serum ammonia and endotoxin levels, improve MHE, and prevent overt HE development in patients with liver cirrhosis.

Synbiotics for Improved Human Health: Recent Developments, Challenges, and Opportunities

Research on combining pro- and prebiotics as synbiotics to enhance human and animal health has accelerated in the past 10 years, including many clinical trials that have assessed a diverse range of synbiotic formulations. In this review, we summarize these studies as well as the commercial applications of synbiotics that are available. In particular, we critically assess the claimed health benefits of synbiotic applications and the ecological and therapeutic factors to consider when designing synbiotics and discuss the implications of these concepts for future research in this field.

Probiotic, Prebiotic, and Brain Development

Recently, a number of studies have demonstrated the existence of a link between the emotional and cognitive centres of the brain and peripheral functions through the bi-directional interaction between the central nervous system and the enteric nervous system. Therefore, the use of bacteria as therapeutics has attracted much interest. Recent research has found that there are a variety of mechanisms by which bacteria can signal to the brain and influence several processes in relation to neurotransmission, neurogenesis, and behaviour. Data derived from both in vitro experiments and in vivo clinical trials have supported some of these new health implications. While recent molecular advancement has provided strong indications to support and justify the role of the gut microbiota on the gut-brain axis, it is still not clear whether manipulations through probiotics and prebiotics administration could be beneficial in the treatment of neurological problems. The understanding of the gut microbiota and its activities is essential for the generation of future personalized healthcare strategies. Here, we explore and summarize the potential beneficial effects of probiotics and prebiotics in the neurodevelopmental process and in the prevention and treatment of certain neurological human diseases, highlighting current and future perspectives in this topic.

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.

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.

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.

Lactulose reduces bacterial DNA translocation, which worsens neurocognitive shape in cirrhotic patients with minimal hepatic encephalopathy

BACKGROUND & AIMS

Minimal hepatic encephalopathy is associated with poor prognosis and mortality in patients with cirrhosis. We aimed at investigating whether bacterial-DNA translocation affects hyperammonaemia and neurocognitive scores in patients with mHE according to the use of lactulose.

METHODS

Observational study including 72 mHE cirrhotic patients, as defined by a psychometric hepatic encephalopathy score (PHES)<-4 and/or a critical flicker frequency (CFF)<39 Hz. Bacterial-DNA, serum ammonia, pro-inflammatory cytokines and nitric oxide levels were evaluated. A second cohort of 40 lactulose-untreated patients were evaluated before and 6-month after lactulose administration (30-60 mL/d).

RESULTS

In the first cohort, bacterial-DNA rate was significantly higher in patients without lactulose (39% vs 23%, P=.03). Serum ammonia and inflammatory markers were significantly increased in patients with bacterial-DNA, regardless the use of lactulose, and correlated with the amount of amplified bacterial-DNA. Neurocognitive scores were significantly worse in bacterial-DNA positive vs negative patients (PHES -7.6±1.1 vs -5.5±1.0; CFF 32.5±2.6 vs 36.2±2.8, P=.01). Lactulose was associated with improved neurocognitive scores in patients without bacterial-DNA. Serum ammonia levels inversely correlated with neurocognitive scores in patients with bacterial-DNA (PHES r=-.84; CFF r=-.72, P=.001). In the second cohort, lactulose reduced bacterial-DNA translocation (36%-16%, P=.02). Neurocognitive scores were significantly improved in bacterial-DNA positive patients who cleared bacterial-DNA during the period on lactulose. Serum ammonia levels correlated with both neurocognitive scores in patients with bacterial-DNA, either before or after lactulose.

CONCLUSION

Bacterial-DNA translocation worsens neurocognitive scores in mHE patients and it is reduced by lactulose, enhancing the relevance of controlling bacterial antigen translocation in these patients.

Minimal hepatic encephalopathy in cirrhosis- how long to treat?

INTRODUCTION

Minimal hepatic encephalopathy (MHE) can reverse after short-term treatment. However, relapse rate of MHE after stopping treatment has not been studied so far. We aimed to evaluate long-term (9 months) efficacy of a short-term (3 months) treatment of MHE with lactulose/rifaximin, for maintenance of remission from MHE.

MATERIAL AND METHODS

In this prospective study, consecutive patients with cirrhosis and MHE were treated with lactulose/rifaximin for 3 months. After treatment, they were followed up for 6 months. Psychometric testing for diagnosis of MHE was performed at baseline, 3 months and 9 months.

RESULTS

Of the 527 patients screened, 351 were found eligible and tested for MHE. Out of these, 112 (31.9%) patients had MHE (mean age 55.3 years; 75% males). They were randomized to receive Rifaximin (n = 57; 1,200 mg/day) or Lactulose (n = 55; 30-120 mL/day) for three months. At 3 months, 73.7% (42/57) patients in Rifaximin group experienced MHE reversal compared to 69.1% (38/55) in Lactulose group (p = 0.677). Six months after stopping treatment, 47.6% (20/42) in rifaximin group and 42.1% (16/38) patients in lactulose group experienced MHE relapse (p = 0.274). The overt hepatic encephalopathy development rate (7.1% vs. 7.9%) and mortality rate (0.23% vs. 0%) were similar in both groups. The Child-Turcotte-Pugh score and model for end stage liver disease (MELD) scores of patients who had MHE relapse were higher compared to those who didn't. On multivariate regression analysis, MELD score was an independent predictor of MHE relapse.

CONCLUSION

Of the patients who became MHE negative after short-term (3 months) treatment with rifaximin/lactulose, almost 50% had a relapse of MHE at 6 months follow-up.

Recent developments in the diagnosis and treatment of covert/minimal hepatic encephalopathy

The terms minimal hepatic encephalopathy and covert hepatic encephalopathy are defined. Clinical assessment is unreliable and both require the use of diagnostic tools. Of these, psychometric tests are the most widely used. They require proper standardization and may be biased by patient cooperation or lack thereof. The measure of the critical flicker frequency and of the electroencephalogram, possibly quantified, are also useful. The alteration of any of them is not strictly parallel in size and may vary from patient to patient. When possible, the use of multiple measures might increase diagnostic reliability. These functional measures should be interpreted within the clinical/biochemical profile of the patient to exclude other disorders. A flow chart for treatment is proposed on the basis of current knowledge.

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.