Long-term effects of Enterococcus faecium SF68 versus lactulose in the treatment of patients with cirrhosis and grade 1-2 hepatic encephalopathy

Probiotics are beneficial for liver cirrhosis: a systematic review and meta-analysis of randomized control trials

Introduction

Gut dysbiosis may play a pivotal role in the pathogenesis of cirrhosis and the severity of complications. Numerous studies have investigated the probiotics as treatments for cirrhosis. However, there is still a lack of definitive evidence confirming the beneficial effects of probiotics on cirrhosis.

Methods

Databases including PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched for randomized controlled trials that compared the effects of probiotic intervention and control treatments, including placebo, no treatment, and active control, on cirrhosis, published from inception to February 2024. Outcomes included hepatic encephalopathy (HE) reversal, safety and tolerability of probiotics, liver function, quality of life, and other cirrhotic-related outcomes. A meta-analysis was conducted to synthesize evidence.

Results

Thirty studies were included. The quantitative synthesis results showed that compared with the control group, probiotics significantly reverse minimal hepatic encephalopathy (MHE) (risk ratio [RR] 1.54, 95% confidence interval [CI] 1.03 to 2.32) and improve HE (RR 1.94, 95% CI 1.24 to 3.06). Additionally, probiotics demonstrated higher safety and tolerability by causing a lower incidence of serious adverse events (RR 0.71, 95% CI 0.58 to 0.87). Probiotics could potentially improve liver function by reducing the Model for End-Stage Liver Disease (MELD) scores (standardized mean difference [SMD] -0.57, 95% CI -0.85 to -0.30), and displayed favorable changes in quality of life (SMD 0.51, 95% CI 0.27 to 0.75) and gut flora (SMD 1.67, 95% CI 1.28 to 2.06).

Conclusion

This systematic review and meta-analysis offers compelling evidence that probiotics are beneficial for cirrhosis by demonstrating reversal of HE, potential for liver function improvements, enhancements in quality of life, and regulation of gut dysbiosis. Furthermore, the apparent safety profile suggests that probiotics are a promising intervention for treating cirrhosis.

Clinical trial registration number

CRD42023478380.

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.

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.

Fatal Idiopathic Hyperammonemia after Induction Chemotherapy for Acute Myeloid Leukemia

Idiopathic hyperammonemia is a rare but potentially fatal complication occurring in patients with acute leukemia or bone marrow transplantation. The role of some specific anticancer drugs may be discussed, but the etiology of hyperammonemia is often multifactorial. We report the case of a 40-year-old woman who developed fatal idiopathic hyperammonemia two weeks after induction chemotherapy with idarubicin-aracytine for acute myeloid leukemia. Despite intensive care management and extrarenal epuration, the patient was declared brain dead two days after hyperammonemia onset.

Blood Ammonia as a Possible Etiological Agent for Alzheimer's Disease

Alzheimer’s disease (AD), characterized by cognitive decline and devastating neurodegeneration, is the most common age-related dementia. Since AD is a typical example of a complex disease that is affected by various genetic and environmental factors, various factors could be involved in preventing and/or treating AD. Extracellular accumulation of beta-amyloid peptide (Aβ) and intracellular accumulation of tau undeniably play essential roles in the etiology of AD. However, interestingly enough, medications targeting Aβ or tau all failed and the only clinically efficient medications for AD are drugs targeting the cholinergic pathway. Also, a very intriguing discovery in AD is that the Mediterranean diet (MeDi), containing an unusually large quantity of Lactobacilli, is very effective in preventing AD. Based on recently emerging findings, it is our opinion that the reduction of blood ammonia levels by Lactobacilli in MeDi is the therapeutic agent of MeDi for AD. The recent evidence of Lactobacilli lowering blood ammonia level not only provides a link between AD and MeDi but also provides a foundation of pharmabiotics for hyperammonemia as well as various neurological diseases.

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.

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.

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.

Microbiota, immunity and the liver

The gut harbors a complex community of over 100 trillion microbial cells known to exist in symbiotic harmony with the host influencing human physiology, metabolism, nutrition and immune function. It is now widely accepted that perturbations of this close partnership results in the pathogenesis of several major diseases with increasing evidence highlighting their role outside of the intestinal tract. The intimate proximity and circulatory loop of the liver and the gut has attracted significant attention regarding the role of the microbiota in the development and progression of liver disease. Here we give an overview of the interaction between the microbiota and the immune system and focus on their convincing role in both the propagation and treatment of liver disease.

Clinical and pathophysiological consequences of alterations in the microbiome in cirrhosis

Cirrhosis is a major cause of mortality worldwide. Exponential rises in prevalence have been observed secondary to increases in obesity and alcohol consumption. Multiple lines of evidence implicate gut-derived bacteria and bacterial ligands as a central driver of pathogenesis. Recent developments in culture-independent techniques have facilitated a more accurate description of microbiome composition in cirrhosis and led to the description of measures of dysbiosis shown to be associated with disease. More importantly, metagenomic studies are adding to an understanding of the functional contribution of the microbiota and may prove to be a more clinically relevant biomarker than phylogenetic studies. Much like other dysbiotic states such as inflammatory bowel disease, the microbiota in cirrhosis is characterized by a low microbial and genetic diversity. Therapeutic strategies to diminish this process are currently limited to selective intestinal decontamination with antibiotics. This review summarizes the available data and develops a framework for the use of current and future treatment strategies to diminish the consequences of dysbiosis in cirrhosis. Interventional strategies to bind bacterial products in the gut lumen and blood, and modulate the magnitude of host sensing mechanisms remain an unmet clinical need. A greater understanding of the host-microbiota interaction in cirrhosis is of key importance to inform future interventional strategies to diminish the currently escalating burden of the disease.

Diets in Encephalopathy

As many as 80% of patients with end-stage liver disease and hepatic encephalopathy have significant protein-calorie malnutrition. Because of the severe hypercatabolic state of cirrhosis, the provision of liberal amounts of carbohydrate (at least 35 to 40 kcal/kg per day), and between 1.2 and 1.6 g/kg of protein is necessary. Protein restriction is not recommended. Branched-chain amino acid supplementation and vegetable protein are associated with improved outcomes. Dietary supplementation with vitamins, minerals (with the notable exception of zinc) and probiotics should be decided on a case-by-case basis.

Gut-liver axis in liver cirrhosis: How to manage leaky gut and endotoxemia

A “leaky gut” may be the cutting edge for the passage of toxins, antigens or bacteria into the body, and may play a pathogenic role in advanced liver cirrhosis and its complications. Plasma endotoxin levels have been admitted as a surrogate marker of bacterial translocation and close relations of endotoxemia to hyperdynamic circulation, portal hypertension, renal, cardiac, pulmonary and coagulation disturbances have been reported. Bacterial overgrowth, increased intestinal permeability, failure to inactivate endotoxin, activated innate immunity are all likely to play a role in the pathological states of bacterial translocation. Therapeutic approach by management of the gut-liver axis by antibiotics, probiotics, synbiotics, prebiotics and their combinations may improve the clinical course of cirrhotic patients. Special concern should be paid on anti-endotoxin treatment. Adequate management of the gut-liver axis may be effective for prevention of liver cirrhosis itself by inhibiting the progression of fibrosis.

The relevance of intestinal dysbiosis in liver transplant candidates

BACKGROUND

The gut microbial ecosystem plays an important role in the pathogenesis of liver diseases. However, the association of microbial community structure with the severity of liver dysfunction is not completely understood.

METHODS

Fecal microflora was assessed in 40 patients with liver cirrhosis listed for primary liver transplantation (LT). Independent associations between fecal microbial counts and serum bilirubin, serum creatinine, international normalized ratio (INR), and the Model for End-stage Liver Disease (MELD) score were established in multiple linear regression models.

RESULTS

Bifidobacterium (standardized regression coefficient [sβ] = -0.549; P < 0.001), Enterococcus (sβ = 0.369; P = 0.004), and yeast (sβ = 0.315; P = 0.018) numbers were independently associated with serum bilirubin, while Escherichia coli counts (sβ = 0.318; P = 0.046) correlated with INR, and Bifidobacterium counts (sβ = 0.410; P = 0.009) with serum creatinine. Only Bifidobacterium (sβ = -0.468; P = 0.003) and Enterococcus (sβ = 0.331; P = 0.029) counts were independent predictors of the MELD score. Bifidobacterium/Enterococcus ratio, proposed as a measure of pre-LT gut dysbiosis, was significantly related to the MELD score following the adjustment for the absolute Bifidobacterium (sβ = -0.333; P = 0.029) and Enterococcus (sβ = -0.966; P = 0.003) numbers. This pre-transplant dysbiosis ratio (PTDR) was significantly correlated with Enterococcus (R = -0.897; P < 0.001) but not with Bifidobacterium (R = 0.098; P = 0.546) counts. Among the other components of gut microflora, only hydrogen peroxide (H2 O2 )-producing Lactobacillus strains significantly influenced Enterococcus counts (sβ = 0.349; P = 0.028) and PTDR (sβ = -0.318; P = 0.046).

CONCLUSION

While the abundance of both Bifidobacterium and Enterococcus is related to liver dysfunction, the size of the Enterococcus population seems to be the most important determinant of pre-LT gut dysbiosis in cirrhotic patients. The H2 O2 -producing Lactobacillus strains potentially ameliorate this dysbiotic state.

Management of overt hepatic encephalopathy

Hepatic encephalopathy (HE) is an important complication of cirrhosis with significant morbidity and mortality. Management of HE primarily involves avoidance of precipitating factors and administration of various ammonia-lowering therapies such as non-absorbable disaccharides, antimicrobial agents like rifaximin and l-ornithine l-aspartate. The non-absorbable disaccharides which include lactulose and lactitol are considered the first-line therapy for the treatment of HE and in primary and secondary prophylaxis of HE. Lactitol is comparable to lactulose in the treatment of HE with fewer side effects. Rifaximin is effective in treatment of HE and recent systemic reviews found it comparable to disaccharides and is effective in secondary prophylaxis of HE. Many agents like l-ornithine l-aspartate, probiotics, zinc, sodium benzoate have been tried either alone or in combination with lactulose for the treatment of HE. Combination therapy of disaccharides either with rifaximin, l-ornithine l-aspartate, probiotics for the treatment of HE needs further validation in large studies.

Gut microbiota and liver diseases

Several studies revealed that gut microbiota are associated with various human diseases, e.g., metabolic diseases, allergies, gastroenterological diseases, and liver diseases. The liver can be greatly affected by changes in gut microbiota due to the entry of gut bacteria or their metabolites into the liver through the portal vein, and the liver-gut axis is important to understand the pathophysiology of several liver diseases, especially non-alcoholic fatty liver disease and hepatic encephalopathy. Moreover, gut microbiota play a significant role in the development of alcoholic liver disease and hepatocarcinogenesis. Based on these previous findings, trials using probiotics have been performed for the prevention or treatment of liver diseases. In this review, we summarize the current understanding of the changes in gut microbiota associated with various liver diseases, and we describe the therapeutic trials of probiotics for those diseases.

Is there a role for probiotics in liver disease?

Intestinal microbiota plays an important role in health and disease. Alteration in its healthy homeostasis may result in the development of numerous liver disorders including complications of liver cirrhosis. On the other hand, restoration and modulation of intestinal flora through the use of probiotics is potentially an emerging therapeutic strategy. There is mounting evidence that probiotics are effective in the treatment of covert and overt hepatic encephalopathy, as well as in the prevention of recurrence of encephalopathy. The beneficial effect of probiotics also extends to liver function in cirrhosis, nonalcoholic fatty liver disease, and alcoholic liver disease. On the other hand, data associating probiotics and portal hypertension is scanty and conflicting. Probiotic therapy has also not been shown to prevent primary or secondary spontaneous bacterial peritonitis. Larger clinical studies are required before probiotics can be recommended as a treatment modality in liver diseases.

Cirrhosis and its complications: Evidence based treatment

Cirrhosis results from progressive fibrosis and is the final outcome of all chronic liver disease. It is among the ten leading causes of death in United States. Cirrhosis can result in portal hypertension and/or hepatic dysfunction. Both of these either alone or in combination can lead to many complications, including ascites, varices, hepatic encephalopathy, hepatocellular carcinoma, hepatopulmonary syndrome, and coagulation disorders. Cirrhosis and its complications not only impair quality of life but also decrease survival. Managing patients with cirrhosis can be a challenge and requires an organized and systematic approach. Increasing physicians’ knowledge about prevention and treatment of these potential complications is important to improve patient outcomes. A literature search of the published data was performed to provide a comprehensive review regarding the management of cirrhosis and its complications.

Disaccharides in the treatment of hepatic encephalopathy

Management of hepatic encephalopathy (HE) primarily involves avoidance of precipitating factors and administration of various ammonia-lowering therapies such as nonabsorbable disaccharides and antimicrobial agents like rifaximin. The nonabsorbable disaccharides which include lactulose and lactitol are considered the first-line therapy for the treatment of HE and minimal hepatic encephalopathy (MHE). Lactulose significantly improves cognitive function and health-related quality of life in patients with MHE. Lactitol is comparable to lactulose in the treatment of HE with fewer side effects. Lactulose has also shown to be effective in primary and secondary prophylaxis of HE. Disaccharides were found to be comparable to rifaximin in recent systemic reviews in the treatment of HE however conclusion was based on inclusion of some poor quality trials. Combination therapy of disaccharides either with rifaximin, L-ornithine L-aspartate,probiotics for the treatment of HE needs further validation in large studies.

Probiotic as a novel treatment strategy against liver disease

CONTEXT

A symbiotic relationship between the liver and intestinal tract enables the healthy status of both organs. Microflora resident in intestinal lumen plays a significant role in hepatocytes function. Alterations to the type and amount of microorganisms that live in the intestinal tract can result in serious and harmful liver dysfunctions such as cirrhosis, nonalcoholic fatty liver disease, alcoholic liver disease, and hepatic encephalopathy. An increased number of pathogens, especially enterobacteriaceae, enterococci, and streptococci species causes the elevation of intestinal permeability and bacterial translocation. The presence of high levels of lipopolysaccharide (LPS) and bacterial substances in the blood result in a portal hypertension and ensuing hepatocytes damage. Several methods including the usage of antibiotics, prebiotics, and probiotics can be used to prevent the overgrowth of pathogens. Compared to prebiotic and antibiotic therapy, probiotics strains are a safer and less expensive therapy. Probiotics are "live microorganisms (according to the FAO/WHO) which when administered in adequate amounts confer a health benefit on the host".

EVIDENCE ACQUISITIONS

Data from numerous preclinical and clinical trials allows for control of the flora bacteria quantity, decreases in compounds derived from bacteria, and lowers proinflammatory production such as TNF-α, IL-6 and IFN-γ via down-regulation of the nuclear factor kappa B (NF-κ B).

RESULTS

On the other hand, probiotic can reduce the urease activity of bacterial microflora. Furthermore, probiotic decreases fecal pH value and reduces ammonia adsorption. In addition, the serum level of liver enzymes and other substances synthesized by the liver are modulated subsequent to probiotic consumption.

CONCLUSIONS

According to our knowledge, Probiotic therapy as a safe, inexpensive and a noninvasive strategy can reduce pathophysiological symptoms and improve different types of liver diseases without side effects.

Combination Therapy for the Treatment and Prevention of Hepatic Encephalopathy

OBJECTIVE:

To evaluate the efficacy and safety of combination therapy for the treatment and prevention of hepatic encephalopathy (HE).

DATA SOURCES:

A PubMed MEDLINE search was conducted (1947-June 2012) using the key terms lactulose, lactitol, nonabsorbable disaccharide, metronidazole, rifaximin, neomycin, probiotics, and hepatic encephalopathy. Searches were limited to include articles published in English.

STUDY SELECTION AND DATA EXTRACTION:

Study selection included published trials, case reports, and case series of humans with HE who were treated with combination therapy of rifaximin, lactulose, lactitol, metronidazole, neomycin, and/or probiotics.

DATA SYNTHESIS:

Only 6 studies that evaluated the benefits of combination drug therapy in the treatment or prevention of HE were available for review. Four studies addressed the treatment of HE, 2 found no significant difference between lactulose/neomycin versus placebo or rifaximin/lactulose, 1 assessed the use of rifaximin/lactulose without a control group, and the fourth found no significant difference between lactulose/probiotics versus either drug alone, although each group showed improvement from baseline. In the 2 prevention trials, both of which stemmed from the same data, the combination of rifaximin/lactulose was superior to lactulose alone, showing significant improvement in mental status, blood ammonia levels, and health-related quality of life and reductions in HE recurrence and hospitalization. Currently, there are no available clinical studies evaluating dual antibiotic therapy, metronidazole with nonabsorbable disaccharides, or antibiotics with probiotics.

CONCLUSIONS:

The evidence evaluating the use of combination therapy for the treatment of HE does not support its widespread use. The combination of rifaximin and lactulose may be considered in the treatment of HE and in patients refractory to monotherapy. The combination of rifaximin and lactulose should be considered for the prevention of HE, especially after the second episode of HE recurrence.

Hepatic encephalopathy: a review of its pathophysiology and treatment

Hepatic encephalopathy (HE) is a broad spectrum of neuropsychiatric manifestations usually affecting individuals with end-stage liver disease. The presence of HE is a poor prognostic sign, with 1-year mortality rates of almost 60%. There is much debate about the underlying mechanisms that result in this syndrome; however, elevated plasma and central nervous system ammonia levels are considered key factors in its pathogenesis. Initial evaluation of the patient presenting with overt HE should include a careful search for predisposing factors, including underlying infection, gastrointestinal (GI) bleeding, electrolyte disturbances, hepatocellular carcinoma, dehydration, hypotension, and excessive use of benzodiazepines, psychoactive drugs, or alcohol. The mainstay of treatment for many years has been nonabsorbable disaccharides, particularly lactulose. Alternative treatments, which usually are second line in patients who do not respond to lactulose, include zinc, antibiotics (neomycin, metronidazole, and rifaximin), ornithine aspartate, sodium benzoate, probiotics, and surgical intervention. Accepted treatments for HE are associated with significant unpleasant side effects, including diarrhea, renal failure, neuropathy, and other GI disturbance. Newer therapies are still in development, and most are awaiting human trials in order to confirm their benefit. These include manganese chelators, L-carnitine, N-methyl-d-aspartate receptor antagonists, blood purification dialysis system, and an intravenous combination of sodium benzoate and phenylacetate.

Systematic review and meta-analysis of randomized trials on probiotics for hepatic encephalopathy

AIM

  The objective of this systematic review and meta-analysis was to assess the efficacy of probiotics and synbiotics in patients with hepatic encephalopathy.

METHODS

  Eligible trials were identified by searching electronic databases including MEDLINE, the Cochrane Library, Science Citation Index and Embase, abstract proceedings, reference lists and ongoing trial registers until 13 October 2010. We included randomized controlled trials comparing probiotics and synbiotics with no intervention, placebo or lactulose in patients with hepatic encephalopathy. The primary outcome measure was improvement in hepatic encephalopathy. RESULTS were expressed as risk rates (RR) with confidence intervals (CI) and intertrial heterogeneity as I(2) .

RESULTS

  Seven trials with a total of 393 patients were analyzed. Compared to placebo or lactulose, treatment with probiotics or synbiotics significantly improved hepatic encephalopathy (RR = 1.40, 95% CI = 1.05-1.86, I(2)  = 5%). Probiotics decreased arterial ammonia (weighted mean difference 15.95; 95% CI = 26.72-3.28; I(2)  = 68%), but not venous ammonia (weighted mean difference 5.23; 95% CI = 21.77-11.30; I(2)  = 89%). Treatment with probiotics or synbiotics did not significantly affect the psychometric tests. Overall adverse events were reported in four trials with no difference between probiotics and placebo groups (RR = 0.32, 95% CI = 0.04-2.57; I(2)  = 59%). Regression analysis showed evidence of small-study effects.

CONCLUSION

  The present meta-analysis suggests that probiotics may be an effective treatment of hepatic encephalopathy, though rigorous evaluation in standardized, randomized, clinical trial with clinically relevant outcomes is still needed.

Microbial translocation in chronic liver diseases

The intestinal microflora is not only involved in the digestion of nutrients, but also in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined as the passage of viable microorganisms or bacterial products (i.e., LPS, lipopeptides) from the intestinal lumen to the mesenteric lymph nodes and other extraintestinal sites. The most recent evidence suggests that microbial translocation (MT) may occur not only in cirrhosis, but also in the early stage of several liver diseases, including alcoholic hepatopathy and nonalcoholic fatty liver disease. Different mechanisms, such as small intestinal bacterial overgrowth, increased permeability of intestinal mucosa, and impaired immunity, may favor MT. Furthermore, MT has been implicated in the pathogenesis of the complications of cirrhosis, which are a significant cause of morbidity and mortality in cirrhotic subjects. Therapeutic strategies aiming at modulating the gut microflora and reducing MT have focused on antibiotic-based options, such as selective intestinal decontamination, and nonantibiotic-based options, such as prokinetics and probiotics. In particular, probiotics may represent an attractive strategy, even though the promising results of experimental models and limited clinical studies need to be confirmed in larger randomized trials.

Secondary prophylaxis of hepatic encephalopathy in cirrhosis: an open-label, randomized controlled trial of lactulose, probiotics, and no therapy

OBJECTIVES

Lactulose is effective in secondary prophylaxis of hepatic encephalopathy (HE). Probiotics improves minimal hepatic encephalopathy (MHE), which predisposes to HE. No study has been conducted on the secondary prophylaxis of HE using probiotics. Our objective was to study the effects of lactulose and probiotics for secondary prophylaxis of HE.

METHODS

Consecutive cirrhotic patients who had recovered from HE were randomized to receive lactulose (Gp-L, 30 ml three times per day), three capsules of probiotics (Gp-P) per day containing 112.5 billion viable lyophilized bacteria per capsule, or no therapy (Gp-N). All patients were assessed by psychometry (number connection test (NCT-A, B), figure connection test if illiterate (FCT-A, B), digit symbol test (DST), and block design test (BDT)), critical flicker frequency (CFF) test, and arterial ammonia at inclusion. The patients were followed up monthly. The primary end point was development of overt HE according to West Haven criteria or a follow-up of 12 months.

RESULTS

Of 360 patients who recovered, 235 (65.2%) met the inclusion criteria (Gp-L, n=80; Gp-P, n=77; and Gp-N, n=78). In all, 38 patients (16.1%) were lost to follow-up and 77 patients developed HE (Gp-L, n=18; Gp-P, n=22; and Gp-N, n=37). There was a significant difference between Gp-L and Gp-N (P=0.001) and between Gp-P and Gp-N (P=0.02) but no difference between the Gp-L and Gp-P groups (P=0.349). The rate of readmission for causes other than HE (Gp-L, Gp-P, and Gp-N, 19:21:28; P=0.134) and deaths (Gp-L:Gp-P:Gp-N=13:11:16; P=0.56) in all three groups were similar. There was a high prevalence of abnormal psychometry test results (NCT-A, 71.5%; NCT-B, 69.2%; DST, 76.9%; and BDT, 85.2%), and FCT-A and -B were abnormal in 35 of 48 patients (72.7%). CFF was <38 Hz in 118 patients (50.2%). Upon multivariate analysis, recurrence of overt HE was significantly associated with two or more abnormal psychometric tests and arterial ammonia after the recovery of an episode of HE.

CONCLUSIONS

Lactulose and probiotics are effective for secondary prophylaxis of HE in patients with cirrhosis.

Bacterial translocation in cirrhosis is not caused by an abnormal small bowel gut microbiota

Sepsis is common in liver cirrhosis, and animal studies have shown the gut to be the principal source of infection, through bacterial overgrowth and translocation in the small bowel. A total of 33 patients were recruited into this study, 10 without cirrhosis and 23 with cirrhotic liver disease. Six distal duodenal biopsies were obtained and snap frozen for RNA and DNA extraction, or frozen for FISH. Peripheral venous bloods were obtained from 30 patients, including 17 chronic liver disease patients. Samples were analysed by real-time PCR, to assess total bacteria, bifidobacteria, bacteroides, enterobacteria, staphylococci, streptococci, lactobacilli, enterococci, Helicobacter pylori and moraxella, as well as TNF-α, IL-8 and IL-18. There was no evidence of bacterial overgrowth with respect to any of the individual bacterial groups, with the exception of enterococci, which were present in higher numbers in cirrhotic patients (P = 0.04). There were no significant differences in any of the cytokines compared to the controls. The small intestinal mucosal microbiota in cirrhotic patients was qualitatively and quantitatively normal, and this shifts the focus of disease aetiology to factors that reduce gut integrity, failure of mechanisms to remove translocating bacteria, or the large bowel as the source of sepsis.

Pathogenesis, diagnosis, and treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a neuropsychiatric disorder seen in patients with advanced liver disease or porto-systemic shunts. Based on etiology and severity of HE, the World Congress of Gastroenterology has divided HE into categories and sub-categories. Many user-friendly computer-based neuropsychiatric tests are being validated for diagnosing covert HE. Currently, emphasis is being given to view HE deficits as a continuous spectrum rather than distinct stages. Ammonia is believed to play crucial role in pathogenesis of HE via astrocyte swelling and cerebral edema. However, evidence has been building up which supports the synergistic role of oxidative stress, inflammation and neurosteroids in pathogenesis of HE. At present, treatment of HE aims at decreasing the production and intestinal absorption of ammonia. But as the role of new pathogenetic mechanisms becomes clear, many potential new treatment strategies may become available for clinician.

Gut microbiota and probiotics in chronic liver diseases

There is a strong relationship between liver and gut: the portal system receives blood from the gut, and intestinal blood content activates liver functions. The liver, in turn, affects intestinal functions through bile secretion into the intestinal lumen. Alterations of intestinal microbiota seem to play an important role in induction and promotion of liver damage progression, in addition to direct injury resulting from different causal agents. Bacterial overgrowth, immune dysfunction, alteration of the luminal factors, and altered intestinal permeability are all involved in the pathogenesis of complications of liver cirrhosis, such as infections, hepatic encephalopathy, spontaneous bacterial peritonitis, and renal failure. Probiotics have been suggested as a useful integrative treatment of different types of chronic liver damage, for their ability to augment intestinal barrier function and prevent bacterial translocation. This review summarizes the main literature findings about the relationships between gut microbiota and chronic liver disease, both in the pathogenesis and in the treatment by probiotics of the liver damage.

Role of nutrition in the management of hepatic encephalopathy in end-stage liver failure

Malnutrition is common in patients with end-stage liver failure and hepatic encephalopathy, and is considered a significant prognostic factor affecting quality of life, outcome, and survival. The liver plays a crucial role in the regulation of nutrition by trafficking the metabolism of nutrients, their distribution and appropriate use by the body. Nutritional consequences with the potential to cause nervous system dysfunction occur in liver failure, and many factors contribute to malnutrition in hepatic failure. Among them are inadequate dietary intake, malabsorption, increased protein losses, hypermetabolism, insulin resistance, gastrointestinal bleeding, ascites, inflammation/infection, and hyponatremia. Patients at risk of malnutrition are relatively difficult to identify since liver disease may interfere with biomarkers of malnutrition. The supplementation of the diet with amino acids, antioxidants, vitamins as well as probiotics in addition to meeting energy and protein requirements may improve nutritional status, liver function, and hepatic encephalopathy in patients with end-stage liver failure.

Current and emerging strategies for treating hepatic encephalopathy

Hepatic encephalopathy (HE) is caused by liver impairment and has a multitude of symptoms in affected patients, including change in level of consciousness, intellectual function, and neuromuscular function. Pharmacologic therapy includes use of nonabsorbable disaccharides (lactulose and lactitol), and antibiotics such as neomycin, paromycin, metronidazole, and rifaximin. Probiotics, acarbose, and drugs such as L-carnitine and flumazenil, may also be helpful in treating HE.

Pharmacotherapy of hepatic encephalopathy in cirrhosis

IMPORTANCE OF THE FIELD

Hepatic encephalopathy (HE) is a major complication encountered in nearly half of the patients with liver cirrhosis.

AREAS COVERED IN THIS REVIEW

A review of the safety and efficacy of current therapies for HE that seek to pre-empt ammonia production and/or to increase its elimination, reducing inflammation, blocking benzodiazepine-like compound production, and supporting systemic hemodynamics.

WHAT THE READER WILL GAIN

Insight into some recent advances in the management of HE that could modify our therapeutic approach to end-stage liver disease. Cirrhotic individuals during an overt HE episode require careful management, focusing on precipitant factors as well as metabolic and hemodynamic derangements.

TAKE HOME MESSAGE

Intestinal ammoniagenesis requires flora modification by antibiotics, prebiotics and probiotics; glutaminase inhibition as well as antibiotics to pre-empt systemic inflammation. Hemodynamic/fluid support is essential. Nutritional support is crucial and hypoproteinemic diets should be avoided. Blocking benzodiazepine-like compounds by the use of flumazenil could be useful in patients with severe, benzodiazepine-induced HE. Long-term rifaximin is well tolerated, does not promote resistance and could decrease overt HE bouts in patients with previous episodes of overt HE. Lactulose is better than no treatment in improving quality of life in patients with minimal HE; it also acts as secondary prophylaxis following overt HE.

Hepatic encephalopathy therapy: An overview

Type-C hepatic encephalopathy (HE) is a severe complication of cirrhosis, which seriously affects quality of life and is strongly related to patient survival. Treatment based on a classical pharmacological approach that is aimed at reducing the production of gut-derived toxins, such as ammonia, is still under debate. Currently, results obtained from clinical trials do not support any specific treatment for HE and our competence in testing old and new treatment modalities by randomized controlled trials with appropriate clinically relevant end-points urgently needs to be improved. On the other hand, patients who are at risk for HE are now identifiable, based on studies on the natural history of the disease. Today, very few studies that are specifically aimed at establishing whether HE may be prevented are available or in progress. Recent studies have looked at non absorbable disaccharides or antibiotics and other treatment modalities, such as the modulation of intestinal flora. In the treatment of severe stage HE, artificial liver supports have been tested with initial positive results but more studies are needed.

Bifidobacterium combined with fructo-oligosaccharide versus lactulose in the treatment of patients with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy (HE) is a reversible neuropsychiatric syndrome in patients with liver disease. It was suggested that Bifidobacterium+fructo-oligosaccharides (FOS) may decrease blood and brain ammonia levels.

AIM

The study was conducted to compare the efficacy of Bifidobacterium+FOS and lactulose in patients with HE.

METHODS

One hundred and twenty-five patients (35 hepatitis B virus infected, 70 hepatitis C virus infected and 20 cryptogenetic cirrhosis) were enrolled in the study. Patients were randomized either to a treatment for 60 days with Bifidobacterium and FOS (group A) or into-group receiving lactulose (group B) in double-blind.

RESULTS

After 30 days of the study period, the Bifidobacterium+FOS-treated patients compared with lactulose-treated patients showed a significant decrease of Trail Making Test B (TMT B) (P<0.005), and a significant increase of Symbol Digit Modalities Test (P<0.001) and Block Design Test (P<0.001).After 60 days of the study period, the Bifidobacterium+FOS-treated patients compared with lactulose-treated patients showed a significant decrease of NH4 fasting HE1 (P<0.001), TMT A (P<0.05), TMT B (P<0.001), and a significant increase of Symbol Digit Modalities Test (P<0.001) and Block Design Test (P<0.001).

CONCLUSION

The treatment with Bifidobacterium+FOS is an alternative to the use of lactulose in patients with cirrhosis, for its usefulness in reducing blood ammonia levels and improvement of psychometric tests.

Emerging drugs for hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy (HE) is a severe complication of cirrhosis, seriously affecting the patients' quality of life. The classical approach aimed at reducing the production of gut-derived toxins, such as ammonia, is under debate as, at the moment, the information obtained from the clinical trials does not support any specific treatment for HE.

OBJECTIVES

i) To discuss present therapeutic strategies and possible future developments; ii) to identify areas of medical needs and iii) to suggest the ideal design and methodology for randomized controlled trials (RCTs) in HE.

METHODS

Current approaches were obtained from already available RCTs or from experimental animal studies. Those approaches developed from studies on HE pathophysiology were considered as working hypotheses for future therapies.

RESULTS/CONCLUSION

Our competence in testing old and new treatment modalities by RCTs with appropriate clinically relevant end points should urgently be improved. The patients at risk of HE are identifiable, and studies specifically aimed at establishing whether HE may be prevented or not are needed. As far as new treatment modalities are concerned, RCTs on the modulators of the intestinal bacterial flora and on the molecular adsorbent recirculating system are already available, but further studies are needed to confirm these promising approaches.

Current trends in the treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common reversible neuropsychiatric syndrome associated with chronic and acute liver dysfunction and significant morbidity and mortality. Although a clear pathogenesis is yet to be determined, elevated ammonia in the serum and central nervous system are the mainstay for pathogenesis and treatment. Management includes early diagnosis and prompt treatment of precipitating factors (infection, gastrointestinal bleeding, electrolyte disturbances, hepatocellular carcinoma, dehydration, hypotension, and use of benzodiazepines, psychoactive drugs, and/or alcohol). Clinical trials have established the efficacy of lactulose and lactitol enemas in the treatment of acute hepatic encephalopathy. Extensive clinical experience has demonstrated the efficacy of oral lactulose and lactitol with the goal of two to three soft bowel movements a day for the treatment of chronic HE. However, lactulose and lactitol have significant gastrointestinal side effects. For patients unable to tolerate lactulose or lactitol or who still have persistent chronic HE with lactulose or lactitol, neomycin, metronidazole and rifaximin are second-line agents. More recent data supports the benefits of rifaximin used solely and as an additional agent with fewer side effects than neomycin or metronidazole. Newer therapies being investigated in humans with clinical promise include nitazoxanide, the molecular adsorbent recirculating system (MARS), L-ornithine phenylacetate, sodium benzoate, and/or sodium phenylacetate and Kremezin^® (AST-120).

Hepatic encephalopathy: pathophysiology and emerging therapies

Hepatic encephalopathy is characterized by neuropsychiatric abnormalities in patients with liver failure. Severe hepatic encephalopathy is an indication for liver transplantation as it portends poor outcome. Treatment of hepatic encephalopathy involves correction of precipitating factors such as sepsis, gastrointestinal bleeding, medications, and electrolyte imbalance. Effective therapies include lactulose and antibiotics such as neomycin, metronidazole, and rifaximin.

Management and treatment of patients with cirrhosis and portal hypertension: recommendations from the Department of Veterans Affairs Hepatitis C Resource Center Program and the National Hepatitis C Program

Cirrhosis represents the end stage of any chronic liver disease. Hepatitis C and alcohol are currently the main causes of cirrhosis in the United States. Although initially cirrhosis is compensated, it eventually becomes decompensated, as defined by the presence of ascites, variceal hemorrhage, encephalopathy, and/or jaundice. These management recommendations are divided according to the status, compensated or decompensated, of the cirrhotic patient, with a separate section for the screening, diagnosis, and management of hepatocellular carcinoma (HCC), as this applies to patients with both compensated and decompensated cirrhosis. In the compensated patient, the main objective is to prevent variceal hemorrhage and any practice that could lead to decompensation. In the decompensated patient, acute variceal hemorrhage and spontaneous bacterial peritonitis are severe complications that require hospitalization. Hepatorenal syndrome is also a severe complication of cirrhosis but one that usually occurs in patients who are already in the hospital and, as it represents an extreme of the hemodynamic alterations that lead to ascites formation, it is placed under treatment of ascites. Recent advances in the pathophysiology of the complications of cirrhosis have allowed for a more rational management of cirrhosis and also for the stratification of patients into different risk groups that require different management. These recommendations are based on evidence in the literature, mainly from randomized clinical trials and meta-analyses of these trials. When few or no data exist from well-designed prospective trials, emphasis is given to results from large series and consensus conferences with involvement of recognized experts. A rational management of cirrhosis will result in improvements in quality of life, treatment adherence, and, ultimately, in outcomes.

The effect of pH, bile and calcium on the adhesion ability of probiotic enterococci of animal origin to the porcine jejunal epithelial cell line IPEC-J2

Examination of adhesion ability using a quantitative assay based on radiolabelled bacteria showed that 10 Enterococcus strains exhibited adhesion ability from 2 to 4%. Enterococcus faecium EF2019 (isolate from rabbit faeces, deponed to Czech Culture of Microorganisms in Brno, CCM 7420) showed the highest adhesion ability (4.0+/-0.4%). With regard to survival, all strains displayed good resistance towards 0.3% oxgall and HCl (pH 3.0). Pretreatment of strains with HCl (pH 3.0) significantly reduced their adhesion. Pretreatment of strains by oxgall significantly reduced the adhesion capacity of E. faecium EF2019, EF1839 and EF319 strains, while the adhesion ability of E. faecium EE3 (isolate from canine feed) slightly increased. Furthermore, addition of calcium (200 mmol/l) significantly increased (P<0.001) the adhesion ability for all strains tested. The adhesion ability of the isolates from rabbits, EF1839 and EF529, as well as the isolate EE3 (strain from canine feed) increased from 2-3% up to 50-55% upon calcium addition. Despite, in general low adhesive properties, strains can survive passage through the gastrointestinal tract.

[Probiotics in gastrointestinal disorders]

Probiotics are preparations containing viable microorganisms that confer potential health benefits for the host. Alteration of bacterial flora both in terms of specific content and concentration may be beneficial in many gastrointestinal disorders. Probiotics are widely used for the management of these conditions in many countries. However, mechanisms of probiotics are incompletely understood. Benefits observed clinically with one species or combinations of species can not be generalized. The optimal dose of treatment has to be determined. Although probiotics are generally regarded safe, caution is needed when using these supplements routinely. It has been proved, that severe adverse events can occur as a complication of probiotic treatment. This review summarizes the recent knowledge concerning the use of probiotics in gastrointestinal disorders.

Control of acute, chronic, and constitutive hyperammonemia by wild-type and genetically engineered Lactobacillus plantarum in rodents

Hyperammonemia is a common complication of acute and chronic liver diseases. Often accompanied with side effects, therapeutic interventions such as antibiotics or lactulose are generally targeted to decrease the intestinal production and absorption of ammonia. In this study, we aimed to modulate hyperammonemia in three rodent models by administration of wild-type Lactobacillus plantarum, a genetically engineered ammonia hyperconsuming strain, and a strain deficient for the ammonia transporter. Wild-type and metabolically engineered L. plantarum strains were administered in ornithine transcarbamoylase-deficient Sparse-fur mice, a model of constitutive hyperammonemia, in a carbon tetrachloride rat model of chronic liver insufficiency and in a thioacetamide-induced acute liver failure mice model. Constitutive hyperammonemia in Sparse-fur mice and hyperammonemia in a rat model of chronic hepatic insufficiency were efficiently decreased by Lactobacillus administration. In a murine thioacetamide-induced model of acute liver failure, administration of probiotics significantly increased survival and decreased blood and fecal ammonia. The ammonia hyperconsuming strain exhibited a beneficial effect at a lower dose than its wild-type counterpart. Improved survival in the acute liver failure mice model was associated with lower blood ammonia levels but also with a decrease of astrocyte swelling in the brain cortex. Modulation of ammonia was abolished after administration of the strain deficient in the ammonium transporter. Intestinal pH was clearly lowered for all strains and no changes in gut flora were observed.

CONCLUSION

Hyperammonemia in constitutive model or after acute or chronic induced liver failure can be controlled by the administration of L. plantarum with a significant effect on survival. The mechanism involved in this ammonia decrease implicates direct ammonia consumption in the gut.

Probiotics and liver disease

Modulation of intestinal flora through the use of probiotics is an emerging therapeutic strategy in the management of chronic liver diseases. This article focuses on the pathophysiologic basis for using probiotics in liver disease and reviews the existing literature on the subject. The role of probiotics is examined in the following areas: a) prevention of infection, b) the hyperdynamic circulatory state of cirrhosis, c) hepatic encephalopathy, d) liver function, and e) nonalcoholic fatty liver disease.

The treatment of hepatic encephalopathy

Current recommendations for the treatment of hepatic encephalopathy are based, to a large extent, on open or uncontrolled trials, undertaken in very small numbers of patients. In consequence, there is ongoing discussion as to whether the classical approach to the treatment of this condition, which aims at reducing ammonia production and absorption using either non-absorbable disaccharides and/or antibiotics, should be revisited, modified or even abandoned. Pros and cons of present therapeutic strategies and possible future developments were discussed at the fourth International Hannover Conference on Hepatic Encephalopathy held in Dresden in June 2006. The content of this discussion is summarized.

The cost-effectiveness and budget impact of competing therapies in hepatic encephalopathy - a decision analysis

BACKGROUND

Treatment options for hepatic encephalopathy have disparate risks and benefits. Non-absorbable disaccharides and neomycin are limited by uncertain efficacy and common dose-limiting side effects. In contrast, rifaximin is safe and effective in hepatic encephalopathy, but is more expensive.

METHODS

We conducted a decision analysis to calculate the cost-effectiveness of six strategies in hepatic encephalopathy: (i) no hepatic encephalopathy treatment, (ii) lactulose monotherapy, (iii) lactitol monotherapy, (iv) neomycin monotherapy, (v) rifaximin monotherapy and (vi) up-front lactulose with crossover to rifaximin if poor response or intolerance of lactulose ('rifaximin salvage'). The primary outcome was cost per quality-adjusted life-year gained.

RESULTS

Under base-case conditions, 'do nothing' was least effective and rifaximin salvage was most effective. Lactulose monotherapy was least expensive, and rifaximin monotherapy was most expensive. When balancing cost and effectiveness, lactulose monotherapy and rifaximin salvage dominated alternative strategies. Compared to lactulose monotherapy, rifaximin salvage cost an incremental US$2315 per quality-adjusted life-year-gained. The cost of rifaximin had to fall below US$1.03/tab in order for rifaximin monotherapy to dominate lactulose monotherapy.

CONCLUSIONS

Rifaximin monotherapy is not cost-effective in the treatment of chronic hepatic encephalopathy at current average wholesale prices. However, a hybrid salvage strategy, reserving rifaximin for lactulose-refractory patients, may be highly cost-effective.

Management of hepatic encephalopathy in patients with cirrhosis

The term hepatic encephalopathy encompasses a spectrum of neuropsychiatric abnormalities seen in patients with liver dysfunction. Distinct syndromes are identified in acute liver failure and cirrhosis. Rapid deterioration in consciousness level and increased intracranial pressure that may result in brain herniation and death are a feature of acute liver failure whereas manifestations of hepatic encephalopathy in cirrhosis include psychomotor dysfunction, impaired memory, increased reaction time, sensory abnormalities, poor concentration and in severe forms, coma. In patients with acute-on-chronic liver failure the pathophysiology remains undefined. Ammonia has been considered central to its pathogenesis. In the brain, the astrocyte is the main site for ammonia detoxification, during the conversion of glutamate to glutamine. An increased ammonia level raises the amount of glutamine within astrocytes, causing an osmotic imbalance resulting in cell swelling and ultimately brain oedema. Recent studies suggest that inflammation and it modulators may play a synergistic role with ammonia in the pathogenesis of hepatic encephalopathy. Therapy of hepatic encephalopathy is directed primarily at reducing ammonia generation and increasing its detoxification. The currently accepted regimens to treat hepatic encephalopathy such as lactulose and protein restricted diets need further clinical trials and therefore placebo controlled clinical trials in hepatic encephalopathy are justified. In liver failure, ammonia metabolism involves multiple organs and therefore ammonia reduction will require simultaneous targeting of these organs. The present review describes the pathophysiological basis of hepatic encephalopathy and evaluates the available therapies.

The pathophysiology of hepatic encephalopathy

Hepatic encephalopathy (HE) is a complicated disorder, the pathophysiology of which remains to be fully understood. This article reviews the current main theories including the potential involvement of ammonia, gamma-aminobutyric acid (GABA)/benzodiazipines and false neurotransmitters. Each theory is critically examined with the evidence for each reviewed carefully, and the potential relationship of ammonia to the remaining two theories explored. Known preciptating factors of HE are also considered as evidence. The conclusions drawn from the evidence provided indicate the large role played by ammonia and suggest that this may be the key to understanding HE as science progresses.