Randomized, double-blind, controlled study of glycerol phenylbutyrate in hepatic encephalopathy

Pathophysiology of hepatic encephalopathy and future treatment options

Understanding of the pathophysiology of hepatic encephalopathy has conditioned new treatment options. Ammonia detoxification in hepatic encephalopathy is regulated by two enzymes: glutaminase or glutamine synthetase. The first produces ammonia and the second detoxifies the ammonia, which is why treatments are aimed at glutaminase inhibition or glutamine synthetase activation. At present, we know that both enzymes are found not only in the liver, but also in the muscle, intestine, kidney, and brain. Therefore, current treatments can be directed at each enzyme at different sites. Awareness of those potential treatment sites makes different options of approach possible in the patient with hepatic encephalopathy, and each approach should be personalized.

A Randomized Controlled Trial Comparing Nitazoxanide Plus Lactulose With Lactulose Alone in Treatment of Overt Hepatic Encephalopathy

BACKGROUND AND AIMS

Hepatic encephalopathy (HE) is a reversible spectrum of neuropsychiatric abnormalities associated with liver dysfunction. Lactulose is a nonabsorbable disaccharide presently used to treat HE. Nitazoxanide (NTZ) has a broad-spectrum activity against urease-producing bacteria, so it decreases ammonia production and is therefore expected to reverse the symptoms of HE. A previous pilot study on HE patients given NTZ and lactulose had encouraging results with regard to amelioration of the clinical picture. Patients showed improvement in mental status and the drug was well-tolerated. Results such as these are encouraging larger studies. The aim of this study was to compare the safety and adequacy of NTZ plus lactulose versus lactulose and placebo in management of overt HE.

METHODS

In total, 120 cirrhotic patients suffering from overt HE were randomly designated to take either NTZ plus lactulose (n=60) or lactulose and placebo (n=60). The Clinical Hepatic Encephalopathy Staging Scale (CHESS) score was assessed for all patients on inclusion to the study and 1 week from the start of treatment.

RESULTS

Both groups evinced an improvement in CHESS score at 1 week, yet the improvement was significantly better in the NTZ group as the score decreased from 4.15±2.09 to 0.00±0.00 compared with 4.96±2.29 to 1.28±0.91 in patients receiving lactulose and placebo (P-value <0.001).

CONCLUSIONS

NTZ significantly decreases the CHESS score and improves mental status in the form of patient alertness, orientation, response to stimulation, and ability to talk. NTZ is safe and well-tolerated apart from infrequent epigastric pain.

Hepatic encephalopathy: Lessons from preclinical studies

Hepatic encephalopathy (HE) is a major complication that is closely related to the progression of end-stage liver disease. Metabolic changes in advanced liver failure can promote cognition impairment, attention deficits and motor dysfunction that may result in coma and death. HE can be subdivided according to the type of hepatic injury, namely, type A, which results from acute liver failure, type B, which is associated with a portosystemic shunting without intrinsic liver disease, and type C, which is due to chronic liver disease. Several studies have investigated the pathogenesis of the disease, and most of the mechanisms have been explored using animal models. This article aimed to review the use of preclinical models to investigate HE. The most used animal species are rats and mice. Experimental models of type A HE include surgical procedures and the administration of hepatotoxic medications, whereas models of types B and C HE are generally surgically induced lesions in liver tissue, which evolve to hepatic cirrhosis. Preclinical models have allowed the comprehension of the pathways related to HE.

Hepatic encephalopathy 2018: A clinical practice guideline by the Italian Association for the Study of the Liver (AISF)

Hepatic encephalopathy (HE) is a common, worrisome and sometimes difficult to manage complication of end-stage liver disease. HE is often recurrent, requiring multiple hospital admissions. It can have serious implications in terms of a patient's ability to perform complex tasks (for example driving), their earning capacity, their social and family roles. This guideline reviews current knowledge on HE definition, pathophysiology, diagnosis and treatment, both by general principles and by way of a summary of available drugs and treatment strategies. The quality of the published, pertinent evidence is graded, and practical recommendations are made. Where possible, these are placed within the Italian health service context, with reference to local diagnosis and management experience.

[Metabolic encephalopathies]

Metabolic encephalopathies (ME) are a common cause of admission to emergency rooms, to hospitalization wards or to intensive care units. They could account for 10 to 20% of causes of comatose states in ICU and could be associated to a poor outcome especially in older patients. Nevertheless, they are often reversible and are associated with a favorable outcome when diagnosed and rapidly treated. They correspond to an altered brain functioning secondary to the deficiency of a substance that is mandatory for the normal brain functioning or to the accumulation of a substance that can be either endogenous or exogenous. It preferably occurs in co-morbid patients, complicating its diagnosis and its management. Altered brain functioning, going from mild neuropsychological impairment to coma, movement disorders especially myoclonus and the absence of any obvious differential diagnosis are highly suggestive of the diagnosis. Whereas some biological samplings and brain MRI are essential to rule out differential diagnosis, some others, such as electroencephalogram, may be able to propose important clues in favor of the diagnosis. Once simple symptomatic measures are introduced, the treatment consists mainly in the correction of the cause. Specific treatment options are only seldom available for ME; this is the case for hepatic encephalopathy and some drug-induced encephalopathies. We will successively describe in this review the main pathophysiological mechanisms, the main causes, favoring circumstances of ME, the differential diagnosis to rule out and the etiological work-up for the diagnosis. Finally, a diagnostic and therapeutic strategy for the care of patients with ME will be proposed.

How to Design a Multicenter Clinical Trial in Hepatic Encephalopathy

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

Mechanistic insight, diagnosis, and treatment of ammonia-induced hepatic encephalopathy

Hepatic encephalopathy is a neuropsychological syndrome due to biochemical disturbance of brain function in advanced liver disease patients. Diagnosis and treatment of the condition is very demanding and has negative toll on finances with increased healthcare utilization. The pathophysiology is not completely understood; however, there is evidence that ammonia plays an important role in the etiology. Conventional methods of solely relying on blood ammonia level to diagnose hepatic encephalopathy did not help much; likewise, the use of lactulose alone in treating hepatic encephalopathy has also been discouraged. This paper analyzed the current knowledge regarding the mechanism of how ammonia disrupts the normal brain function as well as the use of latest diagnosing tools including those under development to evaluate the neuropsychiatric state of patients and their quality of life. The efficacies of lactulose and rifaximin combination for short-term and long-term treatment in addition to nutritional interventions and other drugs undergoing clinical trials were also reviewed.

Antibiotic-Associated Disruption of Microbiota Composition and Function in Cirrhosis Is Restored by Fecal Transplant

Patients with cirrhosis are often exposed to antibiotics that can lead to resistance and fungal overgrowth. The role of fecal microbial transplant (FMT) in restoring gut microbial function is unclear in cirrhosis. In a Food and Drug Administration-monitored phase 1 clinical safety trial, patients with decompensated cirrhosis on standard therapies (lactulose and rifaximin) were randomized to standard-of-care (SOC, no antibiotics/FMT) or 5 days of broad-spectrum antibiotics followed by FMT from a donor enriched in Lachnospiraceae and Ruminococcaceae. Microbial composition (diversity, family-level relative abundances), function (fecal bile acid [BA] deconjugation, 7α-dehydroxylation, short-chain fatty acids [SCFAs]), and correlations between Lachnospiraceae, Ruminococcaceae, and clinical variables were analyzed at baseline, postantibiotics, and 15 days post-FMT. FMT was well tolerated. Postantibiotics, there was a reduced microbial diversity and autochthonous taxa relative abundance. This was associated with an altered fecal SCFA and BA profile. Correlation linkage changes from beneficial at baseline to negative after antibiotics. All of these parameters became statistically similar post-FMT to baseline levels. No changes were seen in the SOC group.

CONCLUSION

In patients with advanced cirrhosis on lactulose and rifaximin, FMT restored antibiotic-associated disruption in microbial diversity and function. (Hepatology 2018; 00:000-000).

Hepatic encephalopathy: Diagnosis and management

Hepatic encephalopathy (HE) is a peculiar kind of brain dysfunction caused by liver insufficiency and/or portal-systemic shunting. It is related to gut-derived substances. It is a relevant cause of morbidity and hospitalisation for patients with cirrhosis. The prognosis of HE is important in terms of survival and re-hospitalisation. It is related to impaired quality of life, falls and poor driving; presents a relevant burden for caregivers and health services; and may negatively impact on patient's job and income. Proper diagnosis and classification are expected to improve HE management. Once diagnosed, the management and therapeutic options for HE are generally clear. The improvement of knowledge in recent years has also clarified which are the further aims of research in this field of medicine. Prophylaxis of overt HE should always be performed, and this is generally secondary prophylaxis. Primary prophylaxis should be done immediately after upper gastrointestinal bleeding. Great advances in the detection and treatment of mild forms of HE are expected to lead to further improvement in patient management.

Update on the Therapeutic Management of Hepatic Encephalopathy

PURPOSE OF REVIEW

Hepatic encephalopathy (HE) is a common and devastating complication to chronic liver disease. In this paper, we summarize the latest research and evidence of both conventional and up-coming treatments.

RECENT FINDINGS

Meta-analyses report beneficial effects of lactulose, branched-chain amino acids, rifaximin, and to some degree L-ornithine L-aspartate on the manifestations of HE in patients with cirrhosis, and generally the numbers needed to treat are low. Recent studies on newer HE treatments including ornithine phenylacetate, spherical carbon, and fecal microbiota transplant also report potentially beneficial effects on HE manifestations. The conventional treatments benefit patients with HE. Newer treatments are under study and more research is needed for their validation.

Hepatic encephalopathy: current challenges and future prospects

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

Hypothesis: role for ammonia neutralization in the prevention and reversal of heart failure

Ammonia plays a central role in the life and death of all living organisms and has been studied for over 100 yr. Ammonia is necessary for growth and development, but it is toxic in excess, and, as a result, differing methods of ammonia neutralization have evolved. After physiological and pathological stress to the heart, tissue ammonia levels rise. Local ammonia neutralization may be inadequate, and excess ammonia may exert its toxic effects. Phenylbutyrate (PBA), which is Federal Drug Administration approved for the treatment of elevated blood ammonia in urea cycle disorders, provides an accessory pathway for ammonia excretion. Recently, PBA has also been found to prevent specific cardiomyopathies. The central theme presents the hypothesis that stress to the myocardium from a variety of environmental sources causes injury, cell death, necrosis, and ammonia production. Ammonia, if not neutralized, exerts downstream toxic effects. Here, data are presented showing that neutralization with PBA alone and PBA combined with angiotensin-converting enzyme inhibition prevent and reverse pathophysiology associated with specific cardiomyopathies. NEW & NOTEWORTHY Ammonia produced after myocardial injury is hypothesized to be an upstream stress contributing to the pathophysiology of heart failure, effects that may be attenuated by a documented ammonia-reducing treatment. Reversal of heart failure can be achieved using an angiotensin-converting enzyme inhibitor combined with an ammonia-reducing treatment.

The Pharmabiotic Approach to Treat Hyperammonemia

Ammonia is constantly produced as a metabolic waste from amino acid catabolism in mammals. Ammonia, the toxic waste metabolite, is resolved in the liver where the urea cycle converts free ammonia to urea. Liver malfunctions cause hyperammonemia that leads to central nervous system (CNS) dysfunctions, such as brain edema, convulsions, and coma. The current treatments for hyperammonemia, such as antibiotics or lactulose, are designed to decrease the intestinal production of ammonia and/or its absorption into the body and are not effective, besides being often accompanied by side effects. In recent years, increasing evidence has shown that modifications of the gut microbiota could be used to treat hyperammonemia. Considering the role of the gut microbiota and the physiological characteristics of the intestine, the removal of ammonia from the intestine by modulating the gut microbiota would be an ideal approach to treat hyperammonemia. In this review, we discuss the significance of hyperammonemia and its related diseases and the efficacy of the current management methods for hyperammonemia to understand the mechanism of ammonia transport in the human body. The possibility to use the gut microbiota as pharmabiotics to treat hyperammonemia and its related diseases is also explored.

Hepatic encephalopathy: a critical current review

Hepatic encephalopathy (HE) is a serious neuropsychiatric complication of cirrhosis and/or porto-systemic shunting. The clinical symptoms are widely variable, extending from subtle impairment in mental state to coma. The utility of categorizing the severity of HE accurately and efficiently serves not only to provide practical functional information about the current clinical status of the patient but also gives valuable prognostic information. In the past 20–30 years, there has been rapid progress in understanding the pathophysiological basis of HE; however, the lack of direct correlation between pathogenic factors and the severity of HE make it difficult to select appropriate therapy for HE patients. In this review, we will discuss the classification system and its limitations, the neuropsychometric assessments and their challenges, as well as the present knowledge on the pathophysiological mechanisms. Despite the many prevalent hypotheses around the pathogenesis of the disease, most treatments focus on targeting and lowering the accumulation of ammonia as well as inflammation. However, treatment of minimal HE remains a huge unmet need and a big concerted effort is needed to better define this condition to allow the development of new therapies. We review the currently available therapies and future approaches to treat HE as well as the scientific and clinical data that support their effectiveness.

Evaluation and Management of Hepatic Encephalopathy: Current Status and Future Directions

Hepatic encephalopathy is a spectrum of neurocognitive manifestations often seen in patients with liver injury or rarely in patients with portosystemic shunting without liver injury. It can be divided into minimal (covert) hepatic encephalopathy and overt hepatic encephalopathy, depending on the severity. Patients with hepatic encephalopathy have compromised clinical outcomes, decreased quality of life, and increased healthcare utilization, often resulting in a heavy financial and personal burden on caregivers. The diagnosis remains largely clinical, with the exclusion of possible other causes for the altered mental status. Current treatment strategies include nonabsorbable disaccharides and antibiotics. This review will focus on the diagnosis, management and clinical impact of hepatic encephalopathy.

Hepatic Encephalopathy: An Update on the Pathophysiology and Therapeutic Options

Hepatic encephalopathy is a spectrum of reversible neuropsychiatric abnormalities, seen in patients with liver dysfunction and/or portosystemic shunting. One of the most debilitating complications of cirrhosis, encephalopathy affects 30-45% of cirrhotics. In addition to significantly affecting the lives of patients and their caregivers, it is also associated with increased morbidity and mortality as well as significant utilization of health care resources. In this paper, we provide an overview on the pathophysiology, diagnosis, management and newer therapies of hepatic encephalopathy.

Hepatic encephalopathy

Hepatic encephalopathy (HE) is a reversible syndrome of impaired brain function occurring in patients with advanced liver diseases. The precise pathophysiology of HE is still under discussion; the leading hypothesis focus on the role of neurotoxins, impaired neurotransmission due to metabolic changes in liver failure, changes in brain energy metabolism, systemic inflammatory response and alterations of the blood brain barrier. HE produces a wide spectrum of nonspecific neurological and psychiatric manifestations. Minimal HE is diagnosed by abnormal psychometric tests. Clinically overt HE includes personality changes, alterations in consciousness progressive disorientation in time and space, somnolence, stupor and, finally, coma. Except for clinical studies, no specific tests are required for diagnosis. HE is classified according to the underlying disease, the severity of manifestations, its time course and the existence of precipitating factors. Treatment of overt HE includes supportive therapies, treatment of precipitating factors, lactulose and/or rifaximin. Routine treatment for minimal HE is only recommended for selected patients.

An update on the use of benzoate, phenylacetate and phenylbutyrate ammonia scavengers for interrogating and modifying liver nitrogen metabolism and its implications in urea cycle disorders and liver disease

INTRODUCTION

Ammonia-scavenging drugs, benzoate and phenylacetate (PA)/phenylbutyrate (PB), modulate hepatic nitrogen metabolism mainly by providing alternative pathways for nitrogen disposal. Areas covered: We review the major findings and potential novel applications of ammonia-scavenging drugs, focusing on urea cycle disorders and liver disease. Expert opinion: For over 40 years, ammonia-scavenging drugs have been used in the treatment of urea cycle disorders. Recently, the use of these compounds has been advocated in acute liver failure and cirrhosis for reducing hyperammonemic-induced hepatic encephalopathy. The efficacy and mechanisms underlying the antitumor effects of these ammonia-scavenging drugs in liver cancer are more controversial and are discussed in the review. Overall, as ammonia-scavenging drugs are usually safe and well tolerated among cancer patients, further studies should be instigated to explore the role of these drugs in liver cancer. Considering the relevance of glutamine metabolism to the progression and resolution of liver disease, we propose that ammonia-scavenging drugs might also be used to non-invasively probe liver glutamine metabolism in vivo. Finally, novel derivatives of classical ammonia-scavenging drugs with fewer and less severe adverse effects are currently being developed and used in clinical trials for the treatment of acute liver failure and cirrhosis.

Hepatic Encephalopathy

This article reviews hepatic encephalopathy (HE) in companion animals. Clinical signs and categories of hepatic disease likely to cause HE are discussed. Ammonia has a key role in pathogenesis and current concepts in body ammonia metabolism are reviewed. Inflammation and manganese accumulation are also thought to be important in pathogenesis. Treatment of HE in acute and chronic cases is discussed along with the rationale for current treatment recommendations. Potential avenues for new treatments and human treatments, which may be transferable to companion animals, are reviewed.

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

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

Glycine and hyperammonemia: potential target for the treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a neuropsychiatric disorder caused by hepatic dysfunction. Numerous studies dictate that ammonia plays an important role in the pathogenesis of HE, and hyperammonemia can lead to alterations in amino acid homeostasis. Glutamine and glycine are both ammoniagenic amino acids that are increased in liver failure. Modulating the levels of glutamine and glycine has shown to reduce ammonia concentration in hyperammonemia. Ornithine Phenylacetate (OP) has consistently been shown to reduce arterial ammonia levels in liver failure by modulating glutamine levels. In addition to this, OP has also been found to modulate glycine concentration providing an additional ammonia removing effect. Data support that glycine also serves an important role in N-methyl D-aspartate (NMDA) receptor mediated neurotransmission in HE. This potential important role for glycine in the pathogenesis of HE merits further investigations.

Where are we going? Translational research in hepatic encephalopathy

Translational medicine, rather than being a unidirectional clinical utilization of basic research discoveries, should be a bidirectional process of cross-fertilization between basic science, medical knowledge and clinical utilization. While steps and processes differ across these branches of research, clear language and proper definitions are prerequisites for effective interaction of researchers to facilitate knowledge development. With respect to Hepatic Encephalopathy, at first glance the areas which require development are around prevention, both to reduce the risk of relapse following an episode of overt HE and to reduce the risk of the first episode of HE. In addition, shortening the duration of episodes of overt HE may also be relevant. Comparisons of treatments and combinations of treatments, acting by different but potentially synergistic mechanisms, are reasonable targets for both basic and applied research.

Impact of ornithine phenylacetate (OCR-002) in lowering plasma ammonia after upper gastrointestinal bleeding in cirrhotic patients

BACKGROUND

Ornithine phenylacetate (OP) has been proven effective in lowering ammonia plasma levels in animals, and to be well tolerated in cirrhotic patients. A trial to assess OP efficacy in lowering plasma ammonia levels versus placebo in cirrhotic patients after an upper gastrointestinal bleeding was performed. The primary outcome was a decrease in venous plasma ammonia at 24 hours.

METHODS

A total of 38 consecutive cirrhotic patients were enrolled within 24 hours of an upper gastrointestinal bleed. Patients were randomized (1:1) to receive OP (10 g/day) or glucosaline for 5 days.

RESULTS

The primary outcome was not achieved. A progressive decrease in ammonia was observed in both groups, being slightly greater in the OP group, with significant differences only at 120 hours. The subanalysis according to Child-Pugh score showed a statistically significant ammonia decrease in Child-Pugh C-treated patients at 36 hours, as well as in the time-normalized area under the curve (TN-AUC) 0-120 hours in the OP group [40.16 μmol/l (37.7-42.6); median (interquartile range) (IQR)] versus placebo group [65.5 μmol/l (54-126);p = 0.036]. A decrease in plasma glutamine levels was observed in the treated group compared with the placebo group, and was associated with the appearance of phenylacetylglutamine in urine. Adverse-event frequency was similar in both groups. No differences in hepatic encephalopathy incidence were observed.

CONCLUSIONS

OP failed to significantly decrease plasma ammonia at the given doses (10 g/day). Higher doses of OP might be required in Child-Pugh A and B patients. OP appeared well tolerated.

Overt hepatic encephalopathy: development of a novel clinician reported outcome tool and electronic caregiver diary

Clinical management and clinical trials of patients with overt hepatic encephalopathy (OHE) are compromised by lack of standardized and reproducible tools for its clinical diagnosis or for caregiver (CG) identification of OHE manifestations which merit medical evaluation. Using an iterative Delphi method, Steering Committee and international hepatologist panel, the West Haven (WH) scale was modified to develop and operationalize a clinician tool for OHE identification and grading (HE Grading Instrument, HEGI™). Major diagnostic criteria included disorientation to time, place, and person, asterixis, lethargy, and coma. Minimum HEGI requirements for OHE diagnosis included: (1) disorientation, or (2) presence of both lethargy and asterixis, or (3) coma. Inter- and intra-rater HEGI reproducibility were 97 % and 98 %, respectively. When applied to a phase II clinical trial population of 178 patients with 388 OHE episodes, HEGI demonstrated excellent concordance with investigator judgement. Additionally, a multi-stage study was conducted to develop a daily CG e-diary, based on OHE manifestations recognizable by CG including speech difficulties, unusual behavior, forgetfulness, confusion, disorientation and level of consciousness. The e-diary was designed for use on smart phone, laptop or desktop, utilized branching logic and skip patterns, incorporated automatic daily completion reminders and real time alerts to clinical sites to facilitate daily standardized CG input and was found to be user friendly and understandable. The HEGI and e-diary, which were developed using methodology accepted by regulatory authorities, are designed to facilitate the design and interpretation of clinical trials for OHE and improve outcomes for OHE patients in clinical practice.

Phenylbutyrate exerts adverse effects on liver regeneration and amino acid concentrations in partially hepatectomized rats

Phenylbutyrate is recommended in urea cycle disorders and liver injury to enhance nitrogen disposal by the urine. However, hypothetically there may be adverse responses to the use of phenylbutyrate in the treatment of liver disease because of its role as a histone deacetylase inhibitor and its stimulatory effect on branched-chain alpha-keto acid dehydrogenase, the rate-limiting enzyme in the catabolism of branched-chain amino acids (BCAA; valine, leucine and isoleucine). We report the effects of phenylbutyrate on liver regeneration and amino acid levels in plasma of partially hepatectomized (PH) rats. Phenylbutyrate or saline was administered at 12-h intervals to PH or laparotomized rats. Phenylbutyrate delayed the onset of liver regeneration compared to the saline-treated controls, as indicated by lower hepatic DNA specific activities 18 and 24( ) h post-PH, decreased hepatic fractional protein synthesis rates 24 h post-PH and lowered the increases in liver weights and hepatic protein and DNA contents 48 h after PH. Hepatic DNA fragmentation (a hallmark of apoptosis) was higher in the phenylbutyrate-treated animals than in controls. Phenylbutyrate decreased the glutamine and BCAA concentrations and the ratio of the BCAA to aromatic amino acids (phenylalanine and tyrosine) in the blood plasma in both hepatectomized and laparotomized animals. In conclusion, the delayed onset of liver regeneration and the decrease in BCAA/AAA ratio in blood suggest that phenylbutyrate administration may be disastrous in subjects with acute hepatic injury and BCAA supplementation is needed when phenylbutyrate is used therapeutically.

Cost-effectiveness analysis of rifaximin-α administration for the reduction of episodes of overt hepatic encephalopathy in recurrence compared with standard treatment in France

BACKGROUND

Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome that occurs most often in a context of acute or chronic liver disease. Despite the seriousness of the pathology, only a few treatments have been developed for improving its management. Rifaximin-α is the first treatment that has been clinically developed for overt HE (OHE) episodes. Recent results of clinical studies demonstrated its significant improvement in the health-related quality of life. The objective of the current study was to estimate the long-term cost-effectiveness of rifaximin-α used in combination with lactulose compared with lactulose monotherapy in cirrhotic patients, who have experienced at least two prior OHE events.

METHODS

A Markov model was used to estimate rifaximin-α cost-effectiveness, evaluating it from the perspective of all contributors as recommended by French health technology assessment guidelines. Costs were based on current French treatment practices. The transition between health states was based on the reanalysis of the rifaximin-α pivotal clinical trials RFHE3001 and RFHE3002. The main outcome of the model was cost per quality adjusted life year (QALY).

RESULTS

The results indicate that rifaximin-α is a cost-effective treatment option with an incremental cost per QALY gained of €19,187 and €18,517 over two different time horizons (2 and 5 years). The robustness of the model was studied using probabilistic sensitivity analysis.

CONCLUSION

For the societal willingness to pay threshold of €27,000 per QALY gained, rifaximin-α in combination with lactulose is a cost-effective and affordable treatment for patients who have experienced at least two prior overt HE episodes.

Management of Neurologic Manifestations in Patients with Liver Disease

OPINION STATEMENT

Liver disease, both in its acute and chronic forms, can be associated with a wide spectrum of neurologic manifestations, both central and peripheral, ranging in severity from subclinical changes to neurocritical conditions. Neurologists are frequently consulted to participate in their management. In this review, we present an overview of management strategies for patients with hepatic disease whose clinical course is complicated by neurologic manifestations. Type A hepatic encephalopathy (HE), which occurs in acute liver failure, is a neurologic emergency, and multiple measures should be taken to prevent and treat cerebral edema. In Type C HE, which occurs in chronic liver disease, management should be aimed at correcting precipitant factors and hyperammonemia. There is an increasing spectrum of drug treatments available to minimize ammonia toxicity. Acquired hepatocerebral degeneration is a rare complication of the chronic form of HE, with typical clinical and brain MRI findings, whose most effective treatment is liver transplantation. Epilepsy is frequent and of multifactorial cause in patients with hepatic disease, and careful considerations should be made regarding choice of the appropriate anti-epileptic drugs. Several mechanisms increase the risk of stroke in hepatic disease, but many of the drugs used to treat and prevent stroke are contraindicated in severe hepatic failure. Hepatitis C infection increases the risk of ischemic stroke. Hemorrhagic stroke is more frequent in patients with liver disease of alcoholic etiology. Viral hepatitis is associated with a wide range of immune-mediated complications, mostly in the peripheral nervous system, which respond to different types of immunomodulatory treatment. Several drugs used to treat hepatic disease, such as the classical and the new direct-acting antivirals, may have neurologic complications which in some cases preclude its continued use.

Fasting Blood Ammonia Predicts Risk and Frequency of Hepatic Encephalopathy Episodes in Patients With Cirrhosis

BACKGROUND & AIMS

There is controversy over the use of measuring blood levels of ammonia (NH3) in the management of patients with overt hepatic encephalopathy (HE).

METHODS

We performed a retrospective analysis of data from a randomized, double-blind study of 178 patients with cirrhosis given glycerol phenylbutyrate (an NH3-lowering agent) or placebo for 16 weeks. Blood samples were collected at baseline and on study days 7 and 14 and NH3 levels were measured. The probabilities of having an HE episode, based on ammonia values, were modeled using binary logistic regression. A Cox proportional model was used to determine the risk of HE episodes in patients with baseline fasting NH3 levels ≤1.5-fold the upper limit of normal (ULN) versus patients with fasting NH3 levels >1.5-fold the ULN.

RESULTS

The risk and frequency of HE episodes and HE-related hospitalizations correlated with baseline (mean, 51 ± 6 μmol/L; ULN, 35 μmol/L) and on-study fasting levels of NH3, and increased sharply at levels >1.5-fold the ULN. Regardless of baseline level, NH3 exposure and the relative risk of HE episodes were decreased by glycerol phenylbutyrate.

CONCLUSIONS

In analysis of data from a phase 2 study of the effects of glycerol phenylbutyrate in patients with cirrhosis, we found that fasting levels of NH3 in blood can identify patients at risk for HE-related morbidity. Patients with HE might benefit from NH3-lowering therapy. ClinicalTrials.gov no: NCT 00999167.

Prospective Multicenter Observational Study of Overt Hepatic Encephalopathy

BACKGROUND

Overt hepatic encephalopathy (OHE) is a frequent complication of decompensated cirrhosis.

AIMS

A multicenter prospective observational study was performed to assess the most commonly recorded presenting manifestations of OHE and its associated health-care burden.

METHODS

Qualifying patients must have experienced ≥1 OHE episode within 30 days of enrollment (qualifying OHE) and were followed for recurrence (on-study OHE).

RESULTS

Two hundred and sixty-five patients were enrolled at 30 sites and followed for up to 9 months (mean 72 days). Seventy-two patients experienced 122 on-study episodes; with 72, 23, and 13 having ≥1, ≥2, or ≥3 on-study episodes with median days to occurrence of the 1st, 2nd, and 3rd episode of 34, 19, and 11, respectively. The most frequently recorded OHE manifestations included confusion (78 %), change in mental status (57 %), disorientation (48 %), lethargy (46 %), and asterixis (45 %). West Haven grade was used inconsistently and recorded for only 28 % of episodes. Most qualifying and on-study episodes occurred on rifaximin (60 and 82 %, respectively) and were associated with hospitalization (68 and 85 %, respectively). Twenty-three patients experienced ≥2 on-study episodes within 2 months of enrollment on average (median 45 days) and accounted for 60 % of on-study episodes.

CONCLUSIONS

In this prospective study, OHE's most commonly recorded presenting manifestations included confusion, altered mental status, disorientation, lethargy, and asterixis. As reflected by frequent recurrence and hospitalizations, OHE, particularly the approximately 10 % of "high-resource-utilizing" patients with frequent recurrence, continues to pose a major unmet medical need and health-care burden despite the use of rifaximin.

Serum Ammonia is Associated With Transplant-free Survival in Hospitalized Patients With Acutely Decompensated Cirrhosis [corrected]

BACKGROUND

As ammonia metabolism is a complex multiorgan process, we sought to determine whether serum ammonia concentrations were associated with transplant-free survival in patients with acutely decompensated cirrhosis and acute-on-chronic liver failure (ACLF).

METHODS

We studied 494 consecutive patients hospitalized with cirrhosis between April 2007 and September 2012 with venous ammonia measured on hospital admission. The primary outcome was transplant-free survival.

RESULTS

Overall, rates of death or transplant within 30 and 90 days were 23.1% (n=114) and 37.7% (n=186), respectively. Forty-six patients (9.2%) underwent liver transplantation within 90 days. In a multivariate Cox proportional hazards model, ammonia concentration was independently associated with death or transplantation within 30 and 90 days after adjusting for model for end-stage liver disease, sodium, white blood cells, and number of ACLF organ failures; every doubling of ammonia was associated with respective hazard ratios of 1.22 (95% confidence interval, 1.03-1.38) and 1.21 (95% confidence interval, 1.04-1.44) for 90- and 30-day transplant or mortality. Notably, after adjusting for ammonia, organ failures were not predictive of outcomes. In a Kaplan-Meier analysis, patients with admission ammonia concentrations >60 μmol/L had significantly lower 90-day transplant-free survival (P=0.0004). Patients with admission ammonia concentrations >60 μmol/L had higher 90- and 30-day risk of death or transplantation (45.2% vs. 31.2%, P=0.001; and 31.6% vs. 15.7%, P<0.0001, respectively).

CONCLUSION

For patients with acutely decompensated cirrhosis, an elevated serum ammonia concentration on admission is associated with reduced 90-day transplant-free survival after adjusting for established predictors.

Possible Phenylacetate Hepatotoxicity During 4-Phenylbutyrate Therapy of Byler Disease

In vitro studies have suggested that 4-phenylbutyrate (PBA) may rescue missense mutated proteins that underlie some forms of progressive familial intrahepatic cholestasis. Encouraging preliminary responses to 4-PBA have been reported in liver disease secondary to mutations in ABCB11 and ATP8B1. A 4-year-old boy with Byler disease was treated with 4-PBA in the forms of sodium PBA (5 months) and then glycerol PBA (7 months) as part of expanded access single patient protocols. During this therapy serum total bilirubin fell and his general well-being was reported to be improved, although total serum bile acids were not reduced. Discontinuation of rifampin therapy, which had been used to treat pruritus, resulted in reversible severe acute liver injury that was potentially the result of phenylacetate toxicity. Interactions between 4-PBA and cytochrome P450 enzymes should be considered in the use of this agent with special attention to potential phenylacetate toxicity.

Contemporary Understanding and Management of Overt and Covert Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a major complication of liver disease that leads to significant morbidity and mortality. Caring for hospitalized patients with HE is becoming more complex, and the economic burden of HE continues to rise. Defining and diagnosing HE, particularly covert HE (CHE), remain challenging. In this article, we review new tools and those currently under development for the diagnosis of CHE and the latest advances in the acute and long-term management of overt HE (OHE) and CHE. In particular, we review the latest data on the use of lactulose and rifaximin for treatment of OHE and summarize the data on adjunctive agents such as sodium benzoate and probiotics.

Post-Transjugular Intrahepatic Portosystemic Shunt Follow-Up and Management in the VIATORR Era

The transjugular intrahepatic portosystemic shunt (TIPS) is a non-selective portosystemic shunt created using endovascular techniques. The first TIPS was performed in Germany in 1988. The VIATORR self-expandable PTFE covered stent-graft (WL Gore, Flagstaff AZ) was approved by the FDA for a TIPS application in December of 2004. This stent-graft offers excellent shunt patency rates and it is possible that it has a beneficial effect on patient survival. Patient surveillance and post-procedural management have changed after the introduction of this stent-graft. This article presents the current management strategies that are followed at our Institution for patients who have undergone a TIPS procedure with a VIATORR stent graft including imaging follow-up, management of encephalopathy, medical management and nutritional aspects.

Acute kidney injury: preclinical innovations, challenges, and opportunities for translation

BACKGROUND

Acute kidney injury (AKI) is a clinically important condition that has attracted a great deal of interest from the biomedical research community. However, acute kidney injury AKI research findings have yet to be translated into significant changes in clinical practice.

OBJECTIVE

This article reviews many of the preclinical innovations in acute kidney injury AKI treatment, and explores challenges and opportunities to translate these finding into clinical practice.

SOURCES OF INFORMATION

MEDLINE, ISI Web of Science.

FINDINGS

This paper details areas in biomedical research where translation of pre-clinical findings into clinical trials is ongoing, or nearing a point where trial design is warranted. Further, the paper examines ways that best practice in the management of AKI can reach a broader proportion of the patient population experiencing this condition.

LIMITATIONS

This review highlights pertinent literature from the perspective of the research interests of the authors for new translational work in AKI. As such, it does not represent a systematic review of all of the AKI literature.

IMPLICATIONS

Translation of findings from biomedical research into AKI therapy presents several challenges. These may be partly overcome by targeting populations for interventional trials where the likelihood of AKI is very high, and readily predictable. Further, specific clinics to follow-up with patients after AKI events hold promise to provide best practice in care, and to translate therapies into treatment for the broadest possible patient populations.

Treatment of Overt Hepatic Encephalopathy

Hepatic encephalopathy (HE) is defined by an altered mental status in the setting of portosystemic shunting, with or without cirrhosis. The basis of HE is probably multi-factorial, but increased ammonia delivery to the brain is thought to play a pivotal role. Medical therapies have typically focused on reducing blood ammonia concentrations. These measures are moderately effective, but further improvements will require identification of new therapeutic targets. Two medications, lactulose and rifaximin, are currently approved for the treatment of HE in the USA - new compounds are available off-label, and are in clinical trials. The presence of HE is associated with a higher risk of death in cirrhotic patients. Liver transplantation typically cures HE, but HE does not increase the MELD score, and therefore does not contribute to the likelihood of liver transplantation.

The Role of Sarcopenia and Frailty in Hepatic Encephalopathy Management

Normal regulation of total body and circulating ammonia requires a delicate interplay in ammonia formation and breakdown between several organ systems. In the setting of cirrhosis and portal hypertension, the decreased hepatic clearance of ammonia leads to significant dependence on skeletal muscle for ammonia detoxification; however, cirrhosis is also associated with muscle depletion and decreased functional muscle mass. Thus, patients with diminished muscle mass and sarcopenia may have a decreased ability to compensate for hepatic insufficiency and a higher likelihood of developing physiologically significant hyperammonemia and hepatic encephalopathy.

Recent advances in the treatment of hyperammonemia

Ammonia is a neurotoxic agent that is primarily generated in the intestine and detoxified in the liver. Toxic increases in systemic ammonia levels predominantly result from an inherited or acquired impairment in hepatic detoxification and lead to potentially life-threatening neuropsychiatric symptoms. Inborn deficiencies in ammonia detoxification mainly affect the urea cycle, an endogenous metabolic removal system in the liver. Hepatic encephalopathy, on the other hand, is a hyperammonemia-related complication secondary to acquired liver function impairment. A range of therapeutic options is available to target either ammonia generation and absorption or ammonia removal. Therapies for hepatic encephalopathy decrease intestinal ammonia production and uptake. Treatments for urea cycle disorders eliminate ammoniagenic amino acids through metabolic transformation, preventing ammonia generation. Therapeutic approaches removing ammonia activate the urea cycle or the second essential endogenous ammonia detoxification system, glutamine synthesis. Recent advances in treating hyperammonemia include using synergistic combination treatments, broadening the indication of orphan drugs, and developing novel approaches to regenerate functional liver tissue. This manuscript reviews the various pharmacological treatments of hyperammonemia and focuses on biopharmaceutical and drug delivery issues.

Novel Ammonia-Lowering Agents for Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a common complication of cirrhosis, leading to frequent hospitalizations. Because ammonia is thought to play an important role in the pathogenesis of HE, therapies specifically aimed at reducing ammonia levels have been developed for conditions causing hyperammonemia, including HE. Ammonia scavengers have been used in HE patients, leading to improvements in symptoms. Bowel cleansing with polyethylene glycol has also been studied recently, resulting in more rapid improvement in acute HE compared with lactulose. Extracorporeal devices have been used in cases of refractory HE but currently are used primarily in research settings and not approved for clinical management for HE.

Diagnosis and Treatment of Low-Grade Hepatic Encephalopathy

Minimal hepatic encephalopathy (mHE) is common among patients with cirrhotic liver disease and causes significant morbidity and mortality. It may present as cognitive impairment, behavioural changes and, less frequently, with neurological symptoms which make diagnosis of the disease challenging. A history of falls and accidents may also be suggestive of mHE. Diagnosis primarily relies on at least two positive psychometric tests of which the psychometric hepatic encephalopathy score (PHES) is essential. Alternatively, PHES and an electroencephalogram may be used to establish a diagnosis. Biochemical markers of encephalopathy currently have no role in the diagnosis of mHE. Treatment is not always advocated for a diagnosis of mHE but is dependent on the degree of impairment caused by the symptoms. After treatment of other metabolic abnormalities and co-morbidities associated with cirrhosis, more specific treatment for mHE largely relies on therapies used to lower ammonia levels. Laxatives and rifaximin are commonly used in treatment and work through decreasing ammonia absorption from the gut. Other therapies, such as BCAA, LOLA, L-carnitine and phenylbutyrate, modify responses to ammonia as well as enhancing metabolism and excretion. mHE resulting from spontaneous portosystemic shunts or transhepatic intraportal systemic shunts may require ablation or reduction of the shunt. Early detection and appropriate treatment of mHE is important to prevent significant cognitive impairments and progression to overt HE.