Hepatic Encephalopathy: Current and Emerging Treatment Modalities

Efficacy and safety of rifaximin in preventing hepatic encephalopathy: A systematic review and meta-analysis

Rifaximin (RFX) is recommended for the treatment of hepatic encephalopathy (HE). However, evidence on whether RFX application could yield additional benefits for preventing HE in patients with cirrhosis is limited. In this study, we aimed to assess the safety and efficacy of RFX in preventing HE. We conducted a systematic search of randomized controlled trials to evaluate the use of RFX by analyzing HE incidence, hospitalization, all-cause mortality, and adverse events. Compared with the control group, RFX had a beneficial effect on the primary prevention of HE (RR = 0.58, 95% CI: 0.50-0.68), with noncomparable effects to NADs (including lactulose and lactitol, RR = 0.65, 95% CI: 0.38-1.11), but more effective than placebo (RR = 0.57, 95% CI: 0.47-0.69). After more than 1 month of RFX treatment, the risk of HE decreased significantly (RR = 0.55, 95% CI: 0.47-0.65). In secondary prevention of HE, RFX decreased the recurrence risk (RR = 0.49, 95% CI: 0.40-0.61). RFX helped to reduce the incidence of HE after transjugular intrahepatic portosystemic stent shunt (TIPSS) (RR = 0.70, 95% CI: 0.51-0.96). In terms of adverse effects, RFX was associated with a lower risk of diarrhea than NADs (RR = 0.04, 95% CI: 0.00-0.25). So, RFX therapy is effective and well-tolerated in preventing HE, and can be used as the first choice in the prophylaxis of HE after TIPSS.

Targeting Metabolism: Innovative Therapies for MASLD Unveiled

The recent introduction of the term metabolic-dysfunction-associated steatotic liver disease (MASLD) has highlighted the critical role of metabolism in the disease's pathophysiology. This innovative nomenclature signifies a shift from the previous designation of non-alcoholic fatty liver disease (NAFLD), emphasizing the condition's progressive nature. Simultaneously, MASLD has become one of the most prevalent liver diseases worldwide, highlighting the urgent need for research to elucidate its etiology and develop effective treatment strategies. This review examines and delineates the revised definition of MASLD, exploring its epidemiology and the pathological changes occurring at various stages of the disease. Additionally, it identifies metabolically relevant targets within MASLD and provides a summary of the latest metabolically targeted drugs under development, including those in clinical and some preclinical stages. The review finishes with a look ahead to the future of targeted therapy for MASLD, with the goal of summarizing and providing fresh ideas and insights.

[Management of hepatic encephalopathy: A general review]

Hepatic encephalopathy is a severe complication with high mortality in patients with hepatopathy and/or portosystemic shunts, partly due to the presence of hyperammonemia because of defective hepatic detoxification. Diagnosis is essentially clinical, characterized by various neuropsychiatric symptoms, possibly associated with hyperammonemia. Complementary tests, such as electroencephalogram to identify metabolic encephalopathy, or specific abnormalities on cerebral magnetic resonance imagery, may also support the diagnosis. Management is essentially based on treatment of triggering factors such as ionic disorders or sepsis, and symptomatic therapy with non-absorbable disaccharides (notably lactulose) or polyethylene glycol, possibly combined with rifaximin. Progression varies according to the initial severity and management of hepatic encephalopathy, but this condition is potentially reversible with treatment.

Hepatic encephalopathy: risk identification and prophylaxis approaches

Hepatic encephalopathy (HE) is a debilitating neurological condition associated with cirrhosis, characterized by cognitive impairment ranging from minimal to overt symptoms. It significantly impacts patients' quality of life and substantially burdens healthcare systems. This review examines current prophylactic strategies for HE, focusing on established treatments, emerging therapies, and predictive tools to identify high-risk patients. Traditional treatments such as lactulose and rifaximin remain the cornerstone of HE management, effectively reducing ammonia levels and preventing recurrence. However, novel approaches like L-ornithine L-aspartate, albumin infusions, and antioxidants like resveratrol show promise in further improving outcomes by addressing underlying pathophysiological mechanisms, including systemic inflammation and gut dysbiosis. Developing predictive models, such as the AMMON-OHE score and clinical-genetic risk assessments, enhances the ability to tailor preventive interventions to individual patient profiles. These advancements are crucial in mitigating the incidence of overt HE, reducing hospital admissions, and improving patient survival rates. The future of HE management lies in personalized medicine, targeting specific inflammatory and metabolic pathways, with the potential integration of genetic manipulation. Continued research is essential to refine these strategies, ultimately aiming to improve the prognosis and quality of life for cirrhotic patients at risk of HE.

Update on the Complications and Management of Liver Cirrhosis

Liver cirrhosis represents the advanced pathological stage of chronic liver disease, characterized by the progressive destruction and regeneration of the hepatic parenchyma over years, culminating in fibrosis and disruption of the vascular architecture. As a leading global cause of morbidity and mortality, it continues to affect millions worldwide, imposing a substantial burden on healthcare systems. Alcoholic/nonalcoholic fatty liver disease and chronic viral hepatitis infection, hepatitis C (HCV) in particular, remain leading causes of cirrhosis. Despite significant advances in understanding the pathogenesis of cirrhosis, its management is still complex due to the multifaceted complications, including ascites, hepatic encephalopathy, variceal bleeding, and hepatocellular carcinoma, all of which severely compromise the patient outcomes and quality of life. This review aims at filling a critical gap by providing a comprehensive summary of the latest evidence on the complications and management of liver cirrhosis. Evidence-based therapies targeting both the etiologies and complications of cirrhosis are essential for improving outcomes. While liver transplantation is considered a definitive cure, advancements in pharmacological therapies offer promising avenues for halting and potentially reversing disease progression. This review summarizes the latest management strategies for cirrhosis and its associated complications, emphasizing the importance of early intervention and novel therapeutic options for improving outcomes and quality of life in affected individuals.

Liver diseases: epidemiology, causes, trends and predictions

As a highly complex organ with digestive, endocrine, and immune-regulatory functions, the liver is pivotal in maintaining physiological homeostasis through its roles in metabolism, detoxification, and immune response. Various factors including viruses, alcohol, metabolites, toxins, and other pathogenic agents can compromise liver function, leading to acute or chronic injury that may progress to end-stage liver diseases. While sharing common features, liver diseases exhibit distinct pathophysiological, clinical, and therapeutic profiles. Currently, liver diseases contribute to approximately 2 million deaths globally each year, imposing significant economic and social burdens worldwide. However, there is no cure for many kinds of liver diseases, partly due to a lack of thorough understanding of the development of these liver diseases. Therefore, this review provides a comprehensive examination of the epidemiology and characteristics of liver diseases, covering a spectrum from acute and chronic conditions to end-stage manifestations. We also highlight the multifaceted mechanisms underlying the initiation and progression of liver diseases, spanning molecular and cellular levels to organ networks. Additionally, this review offers updates on innovative diagnostic techniques, current treatments, and potential therapeutic targets presently under clinical evaluation. Recent advances in understanding the pathogenesis of liver diseases hold critical implications and translational value for the development of novel therapeutic strategies.

Successful portosystemic shunt embolization resolves hepatic encephalopathy and enhances hepatic function and glycemic control in MASH-related cirrhosis: a case report

We report the case of a 70-year-old woman with advanced hepatic encephalopathy (HE) secondary to metabolic dysfunction-associated steatohepatitis (MASH)-related cirrhosis who exhibited an excellent response to portosystemic shunt embolization. Four years earlier, she was diagnosed as having MASH-related cirrhosis accompanied by multiple mesenteric vein-inferior vena cava shunts. As her condition progressed, she suffered recurrent HE that was unresponsive to oral medication, prompting the decision to proceed with shunt embolization. The procedure was successful, with no ensuing HE recurrence. At the 1-year follow-up, she remained free from refractory ascites, and no new shunts were detected. Remarkably, her liver function and glucose metabolism also showed significant improvement after the embolization. This case demonstrates that shunt embolization may be an effective treatment option for refractory HE associated with cirrhosis not only in terms of encephalopathy, but also for ameliorating hepatic function and glycemic control.

A rare, asymptomatic case of an extrahepatic portocaval shunt between the posterior aspect of the portal vein and the inferior vena cava

PURPOSE

We present the case of a rare extrahepatic portocaval shunt that resulted in communication of the portal vein and the inferior vena cava (IVC) at the level between two right renal veins that was incidentally diagnosed with contrast-enhanced computed tomography (CECT) in an asymptomatic patient.

METHODS

A woman in her sixties with abdominal pain and diarrhea of unclear origin underwent exploratory abdominal CECT.

RESULTS

The CECT incidentally revealed an extrahepatic portocaval shunt, whereby a vessel arising from the portal vein superior to the confluence of the superior mesenteric and splenic veins drained into the posterior aspect of the IVC between two right renal veins.

CONCLUSION

The identified vessel was likely a remnant communication between the supra-subcardinal anastomosis and the primitive portal vein. This type of portocaval shunt is rare; although there are no reports of its asymptomatic presence in an adult, recognition thereof may help to identify the cause of symptoms related to hepatic encephalopathy or liver dysfunction. Such a shunt may also provide a minimally invasive approach to the portal vein in procedures that typically rely on access via the transhepatic route.

Intravenous branched-chain amino acid administration for the acute treatment of hepatic encephalopathy: a systematic review and meta-analysis

BACKGROUND

Hepatic encephalopathy (HE) is a severe complication of acute hepatic failure requiring urgent critical care management. Branched-chain amino acids (BCAAs) such as leucine, isoleucine, and valine have been investigated as potential treatments to improve outcomes in patients with acute HE. However, the effectiveness of BCAA administration during the acute phase remains unclear. This study aimed to evaluate the effect of intravenous BCAA (IV-BCAA) treatment on clinical outcomes in patients with acute HE by systematically reviewing and analyzing randomized controlled trials (RCTs).

METHODS

We conducted a comprehensive literature search of MEDLINE, the Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi (ICHUSHI), a Japanese database for medical literature. We included RCTs involving adult patients with acute HE who received IV-BCAA or placebo during the acute phase after admission (< 7 days). Two reviewers independently screened the citations and extracted data. The primary "critical" outcomes were mortality from any cause and improvement in disturbance of consciousness. The secondary "important" outcome included the incidence of complications such as nausea and diarrhea. Risk ratios (RRs) were calculated using random effects models with inverse variance weighting.

RESULTS

Among the 2073 screened records, four met the criteria for quantitative analysis. The analysis included 219 patients: 109 received IV-BCAA, and 110 received placebo. Improvement in the disturbance of consciousness and mortality were not significantly different between the two groups (RR, 1.26; 95% confidence interval [CI], 0.96-1.66; RR, 0.90; 95% CI 0.70-1.16, respectively). Following IV-BCAA administration, the absolute differences of improvement in the disturbance of consciousness and mortality were 118 more per 1000 (95% CI 18 fewer-300 more) and 55 fewer per 1000 (95% CI 165 fewer-88 more), respectively. No significant differences were observed in the incidence of nausea or diarrhea between the two groups.

CONCLUSIONS

Our meta-analysis demonstrates that all outcomes were not significantly different between IV-BCAA treatment and placebo for acute HE. Further RCTs are required to better understand IV-BCAA treatment potential in patients with HE.

The burden of hepatic encephalopathy and the use of albumin as a potential treatment

As a potential sequela of cirrhosis, hepatic encephalopathy (HE) significantly impacts the lives of patients and caregivers and places a substantial burden on the healthcare system. With an increasing incidence over time and a cumulative effect on cognition, HE adversely effects quality of life, morbidity and mortality in patients with cirrhosis. HE can range from minimal or covert (MHE/CHE) to overt and symptomatic (OHE). HE has profound impacts on the health and wellbeing of patients and their families and caregivers. Effective treatments could improve the quality of life for all those affected. In this article, we discuss the existing treatments for HE and focus on the potential role of albumin in the treatment of HE. Currently approved therapies for HE (lactulose and rifaximin) are focused on decreasing the formation of ammonia in the gastrointestinal tract. Among the many agents with alternative mechanisms being investigated for treatment of HE, albumin has been studied in clinical trials with acute (≤ 3 days), short-term (up to 2 weeks) prolonged (> 2 weeks) and long-term administration (months). Current studies indicate that acute or short-term administration of albumin does not provide significant benefit for patients with OHE. However, there is increasing evidence that prolonged or long-term albumin therapy can help improve cognition in OHE and prevent recurrence. Additional studies are needed to substantiate these positive findings for longer term administration of albumin in HE and to increase our comprehension of the pharmacologic basis of the effects of albumin.

Regulation of autophagy by ST3GAL2-mediated α2-3 sialylated glycosphingolipids in hepatic encephalopathy

In neurological diseases, the regulation of autophagy plays a crucial role in their pathology, particularly the relationship between autophagy and hepatic encephalopathy (HE) which merits detailed investigation. Glycosphingolipids are abundant and broadly functional in the nervous system and are closely associated with autophagy. However, the specific link and mechanisms between glycosphingolipids and autophagy in HE remain unclear. This study aims to explore the impact of glycosphingolipid changes on the autophagy in HE and its potential mechanisms. Utilizing lectin microarrays, we observed elevated expression levels of α2-3 sialylated glycosphingolipid in the brain tissue of HBV transgenic mice and ammonia-induced astrocyte models, suggesting that the increase in α2-3 sialylated glycosphingolipid is related to HE. Further research revealed that the increased expression of α2-3 sialylated glycosphingolipid, mediated by ST3GAL2, affects autophagy by regulating the autophagy initiation complex Vps34-Beclin-1. In summary, our research not only comprehensively reveals the changes in brain glycosphingolipid during HBV-related HE but also elucidates the interactions and regulatory mechanisms between α2-3 sialylated glycosphingolipid and autophagy. This study provides a new perspective on understanding the pathogenesis of HE and offers novel theories and targets for future research and treatment strategies.

Safety and efficacy of interventional embolization in cirrhotic patients with refractory hepatic encephalopathy associated with spontaneous portosystemic shunts

This study aimed to assess the safety and efficacy of interventional embolization in cirrhotic patients with refractory hepatic encephalopathy (HE) associated with large spontaneous portosystemic shunts (SPSS). Inverse probability of treatment weighting (IPTW) was employed to minimize potential bias. A total of 123 patients were included in this study (34 in the embolization group and 89 in the control group). In the unadjusted cohort, the embolization group demonstrated significantly better liver function, a larger total area of SPSS, and a higher percentage of patients with serum ammonia levels > 60 µmol/L and the presence of hepatocellular carcinoma (HCC) (all P < 0.05). In the IPTW cohort, baseline characteristics were comparable between the two groups (all P > 0.05). Patients in the embolization group exhibited significantly longer HE-free survival compared to the control group in both the unadjusted and IPTW cohorts (both P < 0.05). Subsequent subgroup analyses indicated that patients with serum ammonia level > 60 μmol/L, hepatopetal flow within the portal trunk, the presence of solitary SPSS, a baseline HE grade of II, and the absence of HCC at baseline showed statistically significant benefit from embolization treatment (all P < 0.05). No early procedural complications were observed in the embolization group. The incidence of long-term postoperative complications was comparable to that in the control group (all P > 0.05). Hence, interventional embolization appears to be a safe and effective treatment modality for cirrhotic patients with refractory HE associated with large SPSS. However, the benefits of embolization were discernible only in a specific subset of patients.

Efficacy and safety of albumin for the treatment of hepatic encephalopathy: an updated systematic review and meta-analysis of randomized controlled trials

Background

Albumin acts as a scavenger of reactive oxygen species and an inhibitor of inflammatory processes that underlie hepatic encephalopathy (HE). However, the role of albumin in hepatic encephalopathy is not well-established. The authors performed this meta-analysis to evaluate the efficacy and safety of albumin in the management of hepatic encephalopathy.

Methods

The authors carried out an extensive search across multiple databases, including MEDLINE (via PubMed), Embase, CENTRAL, and various trial registries, to identify randomized controlled trials (RCTs) evaluating the impact of albumin administration in HE. The authors used a random-effects model for analyses and presented dichotomous outcomes and continuous outcomes as relative risk and mean difference, along with corresponding 95% CIs, respectively. Heterogeneity was assessed using both the I2 index and χ2 test.

Results

Our meta-analysis included 4 RCTs involving 306 patients. Our primary outcomes, mortality, and persistence of HE were reported by all four studies. Albumin was found to significantly decrease mortality in patients with HE [risk ratio (RR) 0.52, 95% CI 0.32-0.83; I2 =0%]. Persistence of HE was found to be comparable between the two groups (RR 0.83, 95% CI 0.68-1.00; I2 =24%). There was no significant difference between the albumin and control groups regarding length of hospital stay (MD -1.55, 95% CI -3.5 to 0.14; I2 =41%), adverse events (RR 1.00, 95% CI 0.87-1.16; I2 =0%), and severe adverse events (RR 0.89, 95% CI 0.59-1.35).

Conclusion

Albumin administration in patients with hepatic encephalopathy decreases mortality but does not significantly impact the persistence of HE. Further high-quality, large-scale randomized controlled trials are needed to provide conclusive evidence.

Sialyltransferase ST3GAL6 silencing reduces α2,3-sialylated glycans to regulate autophagy by decreasing HSPB8-BAG3 in the brain with hepatic encephalopathy

End-stage liver diseases, such as cirrhosis and liver cancer caused by hepatitis B, are often combined with hepatic encephalopathy (HE); ammonia poisoning is posited as one of its main pathogenesis mechanisms. Ammonia is closely related to autophagy, but the molecular mechanism of ammonia's regulatory effect on autophagy in HE remains unclear. Sialylation is an essential form of glycosylation. In the nervous system, abnormal sialylation affects various physiological processes, such as neural development and synapse formation. ST3 β‍-galactoside α2,‍3-sialyltransferase 6 (ST3GAL6) is one of the significant glycosyltransferases responsible for adding α2,3-linked sialic acid to substrates and generating glycan structures. We found that the expression of ST3GAL6 was upregulated in the brains of mice with HE and in astrocytes after ammonia induction, and the expression levels of α2,3-sialylated glycans and autophagy-related proteins microtubule-associated protein light chain 3 (LC3) and Beclin-1 were upregulated in ammonia-induced astrocytes. These findings suggest that ST3GAL6 is related to autophagy in HE. Therefore, we aimed to determine the regulatory relationship between ST3GAL6 and autophagy. We found that silencing ST3GAL6 and blocking or degrading α2,3-sialylated glycans by way of Maackia amurensis lectin-II (MAL-II) and neuraminidase can inhibit autophagy. In addition, silencing the expression of ST3GAL6 can downregulate the expression of heat shock protein β8 (HSPB8) and Bcl2-associated athanogene 3 (BAG3). Notably, the overexpression of HSPB8 partially restored the reduced autophagy levels caused by silencing ST3GAL6 expression. Our results indicate that ST3GAL6 regulates autophagy through the HSPB8-BAG3 complex.

The Health Care Burden of Hepatic Encephalopathy

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

Age and Sex in the Development of Hepatic Encephalopathy: Role of Alcohol

Hepatic encephalopathy (HE) is a neurological condition linked to liver failure. Acute HE (Type A) occurs with acute liver failure, while chronic HE (Type C) is tied to cirrhosis and portal hypertension. HE treatments lag due to gaps in understanding its development by gender and age. We studied how sex and age impact HE and its severity with combined liver toxins. Our findings indicate that drug-induced (thioacetamide, TAA) brain edema was more severe in aged males than in young males or young/aged female rats. However, adding alcohol (ethanol, EtOH) worsens TAA's brain edema in both young and aged females, with females experiencing a more severe effect than males. These patterns also apply to Type A HE induced by azoxymethane (AZO) in mice. Similarly, TAA-induced behavioral deficits in Type C HE were milder in young and aged females than in males. Conversely, EtOH and TAA in young/aged males led to severe brain edema and fatality without noticeable behavioral changes. TAA metabolism was slower in aged males than in young or middle-aged rats. When TAA-treated aged male rats received EtOH, there was a slow and sustained plasma level of thioacetamide sulfoxide (TASO). This suggests that with EtOH, TAA-induced HE is more severe in aged males. TAA metabolism was similar in young, middle-aged, and aged female rats. However, with EtOH, young and aged females experience more severe drug-induced HE as compared to middle-aged adult rats. These findings strongly suggest that gender and age play a role in the severity of HE development and that the presence of one or more liver toxins may aggravate the severity of the disease progression.

Use of bee venom in preventive medicine: An experimental hepatic encephalopathy study in rats

OBJECTIVES

Bee venom is used for medicinal purposes, including the treatment of neurological and liver diseases, but its use as a primary health care approach for preventive purposes requires further exploration. The aim of this study was to provide the first investigation into the possible protective effects of bee venom against hepatic encephalopathy, a serious neurodegenerative disease.

MATERIALS AND METHODS

An experimental animal study was conducted in which healthy albino Sprague-Dawley rats were randomized into three groups: healthy, control and bee venom groups. All rats were tested for locomotor activity at the beginning and end of the study. No intervention was made in the healthy group, whereas hepatic encephalopathy was induced in the control and bee venom groups by the administration of thioacetamide (TAA) (200 mg/kg/day). The bee venom group also received bee venom (5 mg/kg/day) subcutaneously every day for 14 days prior to the TAA administration.

RESULTS

The results for the final locomotor activity tests were statistically better in the bee venom group than in the control group, supporting a beneficial effect of prophylactic bee venom application. Blood ammonia levels and liver weights, determined as indicators of inflammation, were lower in the bee venom group than in the control group and were close to levels in the healthy group, but not statistically significant.

CONCLUSIONS

Bee venom administration has protective effects against the development of hepatic encephalopathy and offers a promising therapeutic opportunity in preventive medicine.

Gut liver brain axis in diseases: the implications for therapeutic interventions

Gut-liver-brain axis is a three-way highway of information interaction system among the gastrointestinal tract, liver, and nervous systems. In the past few decades, breakthrough progress has been made in the gut liver brain axis, mainly through understanding its formation mechanism and increasing treatment strategies. In this review, we discuss various complex networks including barrier permeability, gut hormones, gut microbial metabolites, vagus nerve, neurotransmitters, immunity, brain toxic metabolites, β-amyloid (Aβ) metabolism, and epigenetic regulation in the gut-liver-brain axis. Some therapies containing antibiotics, probiotics, prebiotics, synbiotics, fecal microbiota transplantation (FMT), polyphenols, low FODMAP diet and nanotechnology application regulate the gut liver brain axis. Besides, some special treatments targeting gut-liver axis include farnesoid X receptor (FXR) agonists, takeda G protein-coupled receptor 5 (TGR5) agonists, glucagon-like peptide-1 (GLP-1) receptor antagonists and fibroblast growth factor 19 (FGF19) analogs. Targeting gut-brain axis embraces cognitive behavioral therapy (CBT), antidepressants and tryptophan metabolism-related therapies. Targeting liver-brain axis contains epigenetic regulation and Aβ metabolism-related therapies. In the future, a better understanding of gut-liver-brain axis interactions will promote the development of novel preventative strategies and the discovery of precise therapeutic targets in multiple diseases.

Prevalence, clinical characteristics, and outcomes of spontaneous portosystemic shunt in patients with hepatitis B-related cirrhosis: A multicenter study from China

BACKGROUND

The impact of spontaneous portosystemic shunt (SPSS) on decompensated events and mortality for patients with hepatitis B-related cirrhosis remains poorly investigated.

AIMS

To evaluate the prevalence, clinical characteristics, and outcomes of SPSS among patients with hepatitis B-related cirrhosis.

METHODS

Patients who were diagnosed with hepatitis B-related cirrhosis were retrospectively recruited. All eligible patients were classified into SPSS and non-SPSS groups and their clinical characteristics and outcomes were compared and analyzed.

RESULTS

Of the 1282 patients included in this study, SPSS was identified in 488 patients (38.1%). SPSS group had more severe liver function impairment, higher prevalence and severity of esophageal and gastric varices (EGV), and a higher prevalence of EGV bleeding (EGVB), portal vein thrombosis (PVT), hepatic encephalopathy (HE), ascites, and hepatocellular carcinoma (HCC, all P<0.05). During the follow-up period, SPSS group experienced a significantly higher incidence of EGVB, PVT, and HE (all P<0.05); however, there was no significant difference in the incidence of ascites, HCC, and mortality between the two groups (all P>0.05).

CONCLUSION

With hepatitis B-related cirrhosis, SPSS was common and characterized by severe liver damage and a high prevalence of decompensated events. Moreover, patients with SPSS had higher risks of EGVB, PVT, and HE.

Active Clinical Trials in Hepatic Encephalopathy: Something Old, Something New and Something Borrowed

Hepatic encephalopathy (HE) is a potentially reversible neurocognitive syndrome that occurs in patients with acute or chronic liver disease. Currently, most of the therapies for HE aim to reduce ammonia production or increase its elimination. To date, only two agents have been approved as treatments for HE: lactulose and rifaximin. Many other drugs have also been used, but data to support their use are limited, preliminary or lacking. The aim of this review is to provide an overview and discussion of the current development of treatments for HE. Data from ongoing clinical trials in HE were obtained from the ClinicalTrials.gov website, and a breakdown analysis of studies that were active on August 19th, 2022, was performed. Seventeen registered and ongoing clinical trials for therapeutics targeting HE were identified. More than 75% of these agents are in phase II (41.2%) or in phase III (34.7%). Among them, there are many old acquaintances in the field, such as lactulose and rifaximin, some new entries such as fecal microbiota transplantation and equine anti-thymocyte globulin, an immunosuppressive agent, but also some therapies borrowed from other conditions, such as rifamycin SV MMX and nitazoxanide, two antimicrobial agents FDA approved for the treatment of some types of diarrheas or VE303 and RBX7455, two microbiome restoration therapies, currently used as treatment of high-risk Clostridioides difficile infections. If working, some of these drugs could soon be used as valid alternatives to current therapies when ineffective or be approved as novel therapeutic approaches to improve the quality of life of HE patients.

Hepatic encephalopathy: investigational drugs in preclinical and early phase development

INTRODUCTION

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome, in patients with liver disease, which affects life quality and span. Current treatments are lactulose or rifaximin, acting on gut microbiota. Treatments aiming ammonia levels reduction have been tested with little success.

AREAS COVERED

Pre-clinical research shows that the process inducing HE involves sequentially: liver failure, altered microbiome, hyperammonemia, peripheral inflammation, changes in immunophenotype and extracellular vesicles and neuroinflammation, which alters neurotransmission impairing cognitive and motor function. HE may be reversed using drugs acting at any step: modulating microbiota with probiotics or fecal transplantation; reducing peripheral inflammation with anti-TNFα, autotaxin inhibitors or silymarin; reducing neuroinflammation with sulforaphane, p38 MAP kinase or phosphodiesteras 5 inhibitors, antagonists of sphingosine-1-phosphate receptor 2, enhancing meningeal lymphatic drainage or with extracellular vesicles from mesenchymal stem cells; reducing GABAergic neurotransmission with indomethacin or golexanolone.

EXPERT OPINION

A factor limiting the progress of HE treatment is the lack of translation of research advances into clinical trials. Only drugs acting on microbiota or ammonia reduction have been tested in patients. It is urgent to change the mentality on how to approach HE treatment to develop clinical trials to assess drugs acting on the immune system/peripheral inflammation, neuroinflammation or neurotransmission to improve HE.

Enriched environment ameliorates learning and memory deficits in hepatic encephalopathy mice by restoration of the structure of dendrites and dendritic spines

Cognitive impairment is one of the most common symptoms of hepatic encephalopathy (HE). However, there is a lack of easily implementable rehabilitation strategies. As an easy-to-implement strategy, numerous studies suggest that enriched environment (EE) can be beneficial for cognitive function. However, the effects of EE on learning and memory, as well as dendritic spines plasticity in HE is still unclear. Accordingly, in the present study, we evaluated the effects of EE on the behavior and dendritic spine morphology in an animal model of HE. Our results showed that HE mice have no movement disorder and anxiety, but they exhibit spatial learning and memory dysfunction. Further analysis revealed that the complexity of the dendrites and the maturity of the dendritic spines are reduced in the hippocampus of HE mice. After 4 weeks of housekeeping in EE, dendritic complexity, and dendritic spine maturity, as well as the spatial learning and memory function of HE mice were restored. In conclusion, exposure to EE can positively influence dendritic spines plasticity in the hippocampus and thereby elicit its beneficial effects on cognitive functions in HE.

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.