Reversal of diuretic-induced hepatic encephalopathy with infusion of albumin but not colloid

Albumin: a comprehensive review and practical guideline for clinical use

PURPOSE

Nowadays, it is largely accepted that albumin should not be used in hypoalbuminemia or for nutritional purpose. The most discussed indication of albumin at present is the resuscitation in shock states, especially distributive shocks such as septic shock. The main evidence-based indication is also liver disease. In this review, we provided updated evidence-based instruction for definite and potential indications of albumin administration in clinical practice, with appropriate dosing and duration.

METHODS

Data collection was carried out until November 2023 by search of electronic databases including PubMed, Google Scholar, Scopus, and Web of Science. GRADE system has been used to determine the quality of evidence and strength of recommendations for each albumin indication.

RESULTS

A total of 165 relevant studies were included in this review. Fluid replacement in plasmapheresis and liver diseases, including hepatorenal syndrome, spontaneous bacterial peritonitis, and large-volume paracentesis, have a moderate to high quality of evidence and a strong recommendation for administering albumin. Moreover, albumin is used as a second-line and adjunctive to crystalloids for fluid resuscitation in hypovolemic shock, sepsis and septic shock, severe burns, toxic epidermal necrolysis, intradialytic hypotension, ovarian hyperstimulation syndrome, major surgery, non-traumatic brain injury, extracorporeal membrane oxygenation, acute respiratory distress syndrome, and severe and refractory edema with hypoalbuminemia has a low to moderate quality of evidence and weak recommendation to use. Also, in modest volume paracentesis, severe hyponatremia in cirrhosis has a low to moderate quality of evidence and a weak recommendation.

CONCLUSION

Albumin administration is most indicated in management of cirrhosis complications. Fluid resuscitation or treatment of severe and refractory edema, especially in patients with hypoalbuminemia and not responding to other treatments, is another rational use for albumin. Implementation of evidence-based guidelines in hospitals can be an effective measure to reduce inappropriate uses of albumin.

Role of albumin infusion in cirrhosis-associated complications

Cirrhosis is an advanced-stage liver disease that occurs due to persistent physiological insults such as excessive alcohol consumption, infections, or toxicity. It is characterised by scar tissue formation, portal hypertension, and ascites (accumulation of fluid in the abdominal cavity) in decompensated cirrhosis. This review evaluates how albumin infusion ameliorates cirrhosis-associated complications. Since albumin is an oncotic plasma protein, albumin infusion allows movement of water into the intravascular space, aids with fluid resuscitation, and thereby contributes to resolving cirrhosis-induced hypovolemia (loss of extracellular fluid) seen in ascites. Thus, albumin infusion helps prevent paracentesis-induced circulatory dysfunction, a complication that occurs when treating ascites. When cirrhosis advances, other complications such as spontaneous bacterial peritonitis and hepatorenal syndrome can manifest. Infused albumin helps mitigate these by exhibiting plasma expansion, antioxidant, and anti-inflammatory functions. In hepatic encephalopathy, albumin infusion is thought to improve cognitive function by reducing ammonia concentration in blood and thereby tackle cirrhosis-induced hepatocyte malfunction in ammonia clearance. Infused albumin can also exhibit protective effects by binding to the cirrhosis-induced proinflammatory cytokines TNFα and IL6. While albumin administration has shown to prolong overall survival of cirrhotic patients with ascites in the ANSWER trial, the ATTIRE and MACHT trials have shown either no effect or limitations such as development of pulmonary oedema and multiorgan failure.  Thus, albumin infusion is not a generic treatment option for all cirrhosis patients. Interestingly, cirrhosis-induced structural alterations in native albumin (which lead to formation of different albumin isoforms) can be used as prognostic biomarkers because specific albumin isoforms indicate certain complications of decompensated cirrhosis.

Controversies regarding albumin therapy in cirrhosis

Albumin is the most abundant protein in the human body and is synthetized exclusively by the liver. Therefore, serum albumin levels are reduced in acute and/or chronic liver disease. In cirrhosis, low levels of albumin predict the outcome. In advanced cirrhosis, the quality of albumin is decreased due to high oxidative stress and a proinflammatory state. Therefore, the administration of i.v. albumin would seem to be of pathophysiological relevance and benefit. Yet, the questions that remain are who, when, how much, and how often. While albumin infusion is recommended after large-volume paracentesis, at diagnosis of spontaneous bacterial peritonitis, in acute kidney injury, and in hepatorenal syndrome, the amount and schedule of albumin to be administered require refinement, particularly given complications related to volume overload that have become increasingly apparent. Other indications for albumin such as infections other than spontaneous bacterial peritonitis, hyponatremia, HE, prevention of poor outcomes in hospitalized, and in outpatients with cirrhosis are still debated. The results of studies in these settings are either negative, controversial, or inconclusive. This sheds some doubts regarding the use of albumin as a "one size fits all" strategy. The indication and patient selection are crucial and not always intuitive. The amount and frequency also seem to play a role in the success or failure of albumin. This review will critically discuss the evidence and underline areas where there are indications for albumin use and others where evidence is still insufficient and will have to await the development/results of randomized controlled trials.

Intensive care management of acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a clinical syndrome defined by an acute deterioration of the liver function associated with extrahepatic organ failures requiring intensive care support and associated with a high short-term mortality. ACLF has emerged as a major cause of mortality in patients with cirrhosis and chronic liver disease. ACLF has a unique pathophysiology in which systemic inflammation plays a key role; this provides the basis of novel therapies, several of which are now in clinical trials. Intensive care unit (ICU) therapy parallels that applied in the general ICU population in some organ failures but has peculiar differential characteristics in others. Critical care management strategies and the option of liver transplantation (LT) should be balanced with futility considerations in those with a poor prognosis. Nowadays, LT is the only life-saving treatment that can radically improve the long-term prognosis of patients with ACLF. This narrative review will provide insights on the current understanding of ACLF with emphasis on intensive care management.

Albumin administration in patients with cirrhosis: Current role and novel perspectives

Mortality in cirrhosis is mostly associated with the development of clinical decompensation, characterized by ascites, hepatic encephalopathy, variceal bleeding, or jaundice. Therefore, it is important to prevent and manage such complications. Traditionally, the pathophysiology of decompensated cirrhosis was explained by the peripheral arterial vasodilation hypothesis, but it is currently understood that decompensation might also be driven by a systemic inflammatory state (the systemic inflammation hypothesis). Considering its oncotic and nononcotic properties, albumin has been thoroughly evaluated in the prevention and management of several of these decompensating events. There are formal evidence-based recommendations from international medical societies proposing that albumin be administered in individuals with cirrhosis undergoing large-volume paracentesis, patients with spontaneous bacterial peritonitis, those with acute kidney injury (even before the etiological diagnosis), and those with hepatorenal syndrome. Moreover, there are a few randomized controlled trials and meta-analyses suggesting a possible role for albumin infusion in patients with cirrhosis and ascites (long-term albumin administration), individuals with hepatic encephalopathy, and those with acute-on-chronic liver failure undergoing modest-volume paracentesis. Further studies are necessary to elucidate whether albumin administration also benefits patients with cirrhosis and other complications, such as individuals with extraperitoneal infections, those hospitalized with decompensated cirrhosis and hypoalbuminemia, and patients with hyponatremia.

Albumin therapy for hepatic encephalopathy: current evidence and controversies

Hepatic encephalopathy (HE) is a common complication that occurs in 16-21% of end-stage cirrhosis patients. Emerging evidence suggests that systemic inflammation and oxidative stress may play a role in the development of HE. Recent understanding on the anti-inflammatory properties of human albumin has led to growing interest of using human albumin for the treatment and prevention of HE among decompensated patients. In this review, we aim to discuss the current evidence and controversies of using human albumin for the treatment and prevention of HE in advanced cirrhosis patients.

Albumin in the management of hepatic encephalopathy: A systematic review and meta-analysis

Introduction and objectives It has been suggested that albumin administration could alter the natural history of cirrhosis, and also, that long-term treatment with albumin might be associated with improvement in survival, control of ascites, reduction in the incidence bacterial infections, renal dysfunction, hepatic encephalopathy (HE) and hyponatremia, as well as reduction in length of hospitalization in patients with cirrhosis and ascites. The objective of the present study is to evaluate the role of albumin in the management of HE. Materiales and methods:: This is a systematic review of randomized controlled trials that evaluated the use of albumin in adult patients with cirrhosis and HE. The search for eligible studies was performed in MEDLINE, EMBASE, and Cochrane CENTRAL databases until June 2020. The outcomes of interest were the complete reversal of HE and mortality. Meta-analysis was performed using the random effects model, through the Mantel-Haenszel method. Results: This systematic review was registered at the PROSPERO platform (CRD42020194181). The search strategy retrieved 1,118 articles. After reviewing titles and abstracts, 24 studies were considered potentially eligible, but 22 were excluded after full-text analysis. Finally, 2 studies were included. In the meta-analysis, albumin was associated to significant lower risks of persistent HE (risk ratio - RR = 0.60; 95% confidence interval - CI = 0.38-0.95, p = 0.03) and mortality (RR = 0.54; 95% CI = 0.33-0.90, p = 0.02). Conclusion: Albumin administration improves HE and reduces mortality in patients with cirrhosis and HE.

Efficacy and safety of albumin infusion for overt hepatic encephalopathy: A systematic review and meta-analysis

BACKGROUND AND AIMS

The efficacy and safety of albumin infusion for treatment and prevention of overt hepatic encephalopathy (OHE) among cirrhosis patients remained controversial. We performed a systematic review and meta-analysis to evaluate the benefit of albumin infusion for the treatment and prevention of OHE.

METHODS

We performed a systematic search of 4 electronic databases up to 31st January 2021. The primary outcome was the resolution of OHE. Secondary outcomes were inpatient mortality and albumin-associated adverse events. We assessed the pooled odds' risk, pooled mean differences, 95% confidence interval and heterogeneity using Review Manager Version 5.3.

RESULTS

A total of 12 studies (2,087 subjects) were identified. Among cirrhosis patients with OHE, albumin infusion was associated with a lower pooled risk of OHE (OR=0.43, 95%CI: 0.27, 0.68; I²=0%). Among patients without baseline OHE, albumin infusion was associated with a lower pooled risk of developing OHE (OR=0.53, 95%CI: 0.32, 0.86; I²=62%). Albumin infusion was associated with a lower pooled risk of inpatient mortality (OR=0.36, 95%CI: 0.21, 0.60; I²=0%).

CONCLUSION

Well-powered randomized trials are required to confirm the benefits of albumin infusion for the prevention and treatment of overt hepatic encephalopathy among decompensated cirrhosis patients.

Long-term albumin infusion in decompensated cirrhosis: A review of current literature

Decompensated cirrhosis is characterized by chronic inflammation and severe portal hypertension leading to systemic circulatory dysfunction. Albumin infusion has been widely used in decompensated cirrhosis in patients with spontaneous bacterial peritonitis, large-volume paracentesis and hepatorenal syndrome. Emerging data suggest long-term albumin infusion has both oncotic and non-oncotic properties which may improve the clinical outcomes in decompensated cirrhosis patients. We review the current literature on both the established and potential role of albumin, and specifically address the controversies of long-term albumin infusion in decompensated cirrhosis patients.

Albumin administration in patients with decompensated liver cirrhosis: a meta-analytic update

End-stage liver disease and its related complications exert a huge disease burden and reduce the survival rates of many patients. Albumin administration for patients with decompensated liver cirrhosis has been a controversial topic of discussion. The aim of this study is to investigate whether albumin reduces the mortality and complications of liver cirrhosis compared to standard medical therapy (SMT) alone. Clinical trials in which albumin administration was compared to SMT in patients with liver cirrhosis were included in this meta-analysis. The primary outcome of this study was to evaluate the effect on reducing all-cause mortality. Ascites control, renal failure and hepatic encephalopathy were evaluated as secondary outcomes. Nine clinical trials with 1231 patients were recruited and analyzed using the quality effect model. Mortality rate was significantly reduced in the albumin group [relative risk (RR) 0.73, 95% confidence interval (CI) 0.56-0.96]. Heterogeneity was mild across all studies (I2 23.3%). Studies reporting long-term albumin (LTA) administration were found to have a significant decrease in mortality (RR 0.57, 95% CI 0.44-0.73). However, studies reporting short-term albumin administration were found to have no effect on mortality (RR 0.90, 95% CI 0.56-1.45). Furthermore, there was a significant decrease in the incidence of all secondary outcomes. This meta-analysis provides evidence that LTA administration is significantly effective in reducing the mortality of liver cirrhosis compared to SMT. Albumin administration was also shown to reduce the occurrence of ascites, renal failure and hepatic encephalopathy as complications of liver cirrhosis.

Association between serum albumin and cognitive dysfunction in hepatic encephalopathy: An exploratory data analysis

Background and Aim

Because covert hepatic encephalopathy (CHE) has been shown to affect the prognosis of cirrhotic patients, early diagnosis of hepatic encephalopathy (HE) is a prerequisite for the preservation of patients' quality of life and for prophylaxis of overt HE. The aim of this study was to identify a clinical parameter to predict impairment of cognitive function in cirrhotic patients with early‐stage HE.

Methods

We investigated the data from 172 patients with cirrhotic or idiopathic portosystemic shunt (PSS) in phase II/III trials of rifaximin in Japan. Classification and regression trees (CARTs) were constructed to identify clinical profiles related to cognitive dysfunction as indicated by the prolongation of time required for the Number Connection Test (NCT‐B).

Results

CART analysis detected age 65 years as the variable for the initial split, and serum albumin level was selected as the variable for the second split among patients aged ≤65 years. In 27 cirrhotic patients aged ≤65 years without PSS, receiver operating characteristic curve analysis revealed that the optimal albumin level cutoff point was 3.05 g/dL, and the area under the curve was 0.80 for the prolongation of NCT‐B time, which was higher than that of the branched‐chain amino acids‐to‐tyrosine ratio (0.46), the prothrombin time–international normalized ratio (PT‐INR) (0.68), serum ammonia (0.61), and total bilirubin (0.69).

Conclusions

Lower serum albumin level as a clinical biomarker associated with impaired cognitive function may be available as a screening examination for early‐stage HE in cirrhotic patients aged ≤65 years without PSS before undergoing neuropsychological tests.

Optimal Management of Cirrhotic Ascites: A Review for Internal Medicine Physicians

Clinical history of liver cirrhosis is characterised by two phases: the asymptomatic phase, also termed 'compensated cirrhosis', and the phase of complications due to the development of portal hypertension and liver dysfunction, also termed 'decompensated cirrhosis', in which patients may develop ascites, the most frequent and clinically relevant complication of liver cirrhosis. Ascites can be classified into uncomplicated and complicated according to the development of refractoriness, spontaneous bacterial peritonitis (SBP) or the association with hepatorenal syndrome (HRS). In this narrative review, we will extensively discuss the optimal pharmacological and non-pharmacological management of cirrhotic ascites with the aim to offer an updated practical guide to Internal Medicine physicians. According to the amount of fluid in the abdominal cavity, uncomplicated ascites is graded from 1 to 3, and the cornerstone of its management consists of restriction of salt intake, diuretics and large-volume paracentesis (LVP); in recent years, long-term administration of human albumin has acquired a new interesting role. Refractory ascites is primarily managed with LVP and transjugular intrahepatic portosystemic shunt (TIPS) placement in selected patients. The occurrence of renal impairment, especially HRS, worsens the prognosis of patients with cirrhotic ascites and deserves a specific treatment. Also, the management of SBP faces the rising and alarming spread of antibiotic resistance. Hepatic hydrothorax may even complicate the course of the disease and its management is a challenge. Last but not least, liver transplantation (LT) is the ultimate and more effective measure to offer to patients with cirrhotic ascites, particularly when complications occur.

Novel Therapies in Hepatic Encephalopathy

Despite widespread use of lactulose and rifaximin for the treatment of hepatic encephalopathy, this complication of advanced liver disease remains a major burden on the health care system in the United States and continues to predispose to high morbidity and mortality. Several agents have surfaced over recent years with promise to treat hepatic encephalopathy and mitigate the cognitive impairment associated with this disease process. The purpose of this article is to highlight the leading emerging therapies in hepatic encephalopathy as well as their therapeutic targets.

Recent advances in understanding and managing hepatic encephalopathy in chronic liver disease

Hepatic encephalopathy (HE) is a common, severe complication of advanced chronic liver disease (CLD) and has a devastating impact on the patient’s quality of life and prognosis. The neurotoxin ammonia and the presence of systemic and neurological inflammation are considered the key drivers of this neuropsychiatric syndrome. Treatment options available in routine clinical practice are limited, and the development of novel therapies is hampered owing to the complexity and heterogeneity of HE. This review article aims to outline the current understanding of the pathomechanisms of HE and the recent advances in the identification and development of novel therapeutic targets.

Albumin: Indications in chronic liver disease

Albumin is currently employed as a plasma expander to prevent and treat specific complications of cirrhosis with ascites, such as the prevention of paracentesis-induced circulatory dysfunction and renal dysfunction induced by spontaneous bacterial peritonitis, as well as the diagnosis and treatment of acute kidney injury and hepatorenal syndrome. Recently, evidence has shown that long-term albumin administration in patients with decompensated cirrhosis reduces mortality and incidence of complications, eases the management of ascites, is cost effective, and has a good safety profile.

Impaired albumin function: a novel potential indicator for liver function damage?

Albumin is the most abundant plasma protein and albumin infusion is commonly used. Conventionally, the biologic and therapeutic effects of albumin have been thought to be due to its oncotic properties. However, albumin has a variety of biologic functions, including molecular transport, anti-oxidation, anti-inflammation, endothelial stabilisation, anti-thrombotic effects, and the adjustment of capillary permeability. Despite this, the functions of albumin have not been thoroughly investigated. Recent studies have shown non-alcoholic fatty liver disease (NAFLD), viral hepatitis, cirrhosis, and liver failure to be associated with impairments in albumin function, which are associated with impairments in liver function and disease prognosis. Post-translational modifications of albumin cause structural modifications that affect protein function. Recently, the concentration of albumin associated with normal function, the 'efficient albumin concentration', has been attracting more interest. In addition, although many biologic markers, including albumin concentration, are widely used for the assessment of early liver dysfunction in patients with liver diseases, the predictive values are unsatisfactory. However, clinical evidence has suggested that albumin function may represent a novel biomarker of early impairment in liver function. In this review, we summarise the factors affecting albumin function and discuss the clinical significance of impairments in albumin function in various liver diseases.Key messagesThe importance of albumin depends not only on its concentration, but also on its various physiological functions.Impaired albumin function has been reported in a variety of liver diseases, and is associated with disease severity and prognosis, thereby proposing the concept of 'effective albumin concentration'.Albumin dysfunction occurs earlier than other conventional indicators, and albumin dysfunction may be a new biomarker of early impairment in liver function.Many exogenous and endogenous factors lead to post-translational modifications of albumin, which alters the three-dimensional structure of albumin, resulting in a decrease in its biological activity.

Albumin infusion may decrease the incidence and severity of overt hepatic encephalopathy in liver cirrhosis

BACKGROUND

The role of human albumin infusion for the prevention and treatment of overt hepatic encephalopathy (HE) in liver cirrhosis remains unclear.

RESULTS

Among the 708 patients without pre-existing overt HE, albumin infusion significantly decreased the incidence of overt HE (4.20% versus 12.70%, P<0.001) and in-hospital mortality (1.70% versus 5.40%, P=0.008). Among the 182 patients with overt HE at admission or during hospitalization, albumin infusion significantly improved overt HE (84.60% versus 68.10%, P=0.009) and decreased in-hospital mortality (7.70% versus 19.80%, P=0.018). Meta-analysis of 6 studies found that albumin infusion might decrease the risk of overt HE (OR=1.63, P=0.07), but the difference was not statistically significant. Meta-analysis of 3 studies found that albumin infusion significantly improved overt HE (OR=2.40, P=0.04).

CONCLUSIONS

Based on the results of our retrospective study and meta-analysis, albumin infusion might prevent from the occurrence of overt HE and improve the severity of overt HE in cirrhosis. Our retrospective study also suggested that albumin infusion improved the outcomes of cirrhotic patients regardless of overt HE.

METHODS

Cirrhotic patients consecutively admitted between January 2010 and June 2014 were considered in a retrospective study. A 1:1 propensity score matching analysis was performed. Additionally, publications regarding albumin infusion for the management of overt HE were systematically searched. Meta-analyses were performed by random-effect model. Odds ratio (OR) was calculated.

Randomized controlled trial comparing lactulose plus albumin versus lactulose alone for treatment of hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy (HE) is associated with poor prognosis and treatment of HE is primarily directed at the reduction of the blood ammonia levels. The study evaluated the efficacy and safety of albumin plus lactulose versus lactulose alone for treatment of overt HE.

METHODS

In prospective randomized controlled trial, 120 patients with overt HE were randomized in two groups: group A lactulose plus albumin (n = 60) and group B lactulose alone (n = 60). Primary end point was complete reversal of HE, and secondary end points were mortality and hospital stay.

RESULTS

A total of 120 patients (mean age 40.4 ± 9.3 years) were included in this study. Thirty-six (30%) patients were in Child-Turcotte-Pugh (CTP) class B, and 84 (70%) were in CTP Class C. Mean CTP score was 9.8 ± 2.1, and model for end-stage liver disease score was 26.1 ± 5.3. Twenty seven (22.5%) had grade 2, 57 (47.5%) had grade 3, and 36 (30%) had grade 4 HE at the time of admission. Forty-five (75%) patients in group A compared with 32 (53.3%) patients in group B had complete reversal of HE (P = 0.03). Mortality was significantly lower in lactulose plus albumin group (11[18.3%]) versus lactulose alone (19 [31.6%], [P < 0.05]). There was significant decrease in levels of arterial ammonia, interleukin-6, interleukin-18, tumor necrosis factor-alpha, and endotoxins after treatment in both groups; however, the delta decrease was significantly higher in group A compared with group B. Hospital stay was shorter in group A.

CONCLUSIONS

Combination of lactulose plus albumin is more effective than lactulose alone in treatment of overt HE.

Role of albumin in cirrhosis: from a hospitalist's perspective

Albumin, a negatively charged globular protein encoded on chromosome 4, is one of the most abundant proteins in the plasma and accounts for approximately 75% of plasma oncotic pressure. The role of albumin in the management of various disease states has shown to be beneficial historically. Low serum albumin is a predictor of mortality and poor outcomes. In cirrhotics undergoing paracentesis, albumin infusion prevents rapid re-accumulation of ascitic fluid while simultaneously decreasing the risk of post-paracentesis related circulatory dysfunction. Additionally, albumin is utilized in patients with hepatorenal syndrome (HRS) and spontaneous bacterial peritonitis (SBP). Overall, albumin appears to be an effective pharmacological agent in the management of cirrhosis and its complications.

Clinical Implications Associated With the Posttranslational Modification-Induced Functional Impairment of Albumin in Oxidative Stress-Related Diseases

Recent research findings indicate that the posttranslational modification of human serum albumin (HSA) such as oxidation, glycation, truncation, dimerization, and carbamylation is related to certain types of diseases. We report herein on a simple and rapid analytical method, using an electrospray ionization time-of-flight mass spectrometry technique, that allows posttranslational modifications of HSA to be quantitatively and qualitatively evaluated with a high degree of sensitivity. In patients with chronic liver disease, chronic renal disease, and diabetes mellitus, an increase in the level of oxidized cysteine-34 (Cys-34) of HSA accompanied by a decrease in the level of reduced Cys-34 was observed. The redox status of Cys-34 was correlated with ligand binding and the antioxidative functions of HSA. Available evidence indicates that monitoring the redox state of Cys-34 not only could be a useful marker for evaluating the progression of disease and its complications but also would permit therapeutic efficacy to be predicted. The redox state of Cys-34 was also used as an index of the quality of HSA preparations. These data suggest that monitoring the posttranslational modifications of HSA can be important, because the function of HSA is related not only to its serum concentration but also to the preservation of its structural integrity under disease conditions.

No effect of albumin infusion on the prevention of hepatic encephalopathy after transjugular intrahepatic portosystemic shunt

Hepatic encephalopathy (HE) is a major problem in patients submitted to TIPS. Previous studies identified low albumin as a factor associated to post-TIPS HE. In cirrhotics with diuretic-induced HE and hypovolemia, albumin infusion reduced plasma ammonia and improved HE. Our aim was to evaluate if the incidence of overt HE (grade II or more according to WH) and the modifications of venous blood ammonia and psychometric tests during the first month after TIPS can be prevented by albumin infusion. Twenty-three patients consecutively submitted to TIPS were enrolled and treated with 1 g/Kg BW of albumin for the first 2 days after TIPS followed by 0,5 g/Kg BW at day 4th and 7th and then once a week for 3 weeks. Forty-five patients included in a previous RCT (Riggio et al. 2010) followed with the same protocol and submitted to no pharmacological treatment for the prevention of HE, were used as historical controls. No differences in the incidence of overt HE were observed between the group of patients treated with albumin and historical controls during the first month (34 vs 31 %) or during the follow-up (39 vs 48 %). Two patients in the albumin group and three in historical controls needed the reduction of the stent diameter for persistent HE. Venous blood ammonia levels and psychometric tests were also similarly modified in the two groups. Survival was also similar. Albumin infusion has not a role in the prevention of post-TIPS HE.

Albumin in chronic liver disease: structure, functions and therapeutic implications

Human serum albumin is a critical plasma protein produced by the liver with a number of accepted clinical indications in chronic liver disease including management of circulatory and renal dysfunction in patients with ascites. Advanced cirrhosis is characterised by reduced albumin concentration as well as impaired albumin function as a result of specific structural changes and oxidative damage. Traditionally, the biologic and therapeutic role of albumin in liver disease was attributed to its oncotic effects but it is now understood that albumin has a wide range of other important physiologic functions such as immunomodulation, endothelial stabilisation, antioxidant effects and binding multiple drugs, toxins and other molecules. This review discusses the multifunctional properties of albumin and, in particular, the biologic and clinical implications of structural and functional changes of albumin that are associated with cirrhosis. Based on these insights, we explore the current and potential future therapeutic uses of albumin in liver disease.

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.

A Model for Predicting Development of Overt Hepatic Encephalopathy in Patients With Cirrhosis

BACKGROUND & AIMS

Overt hepatic encephalopathy (HE) affects patients' quantity and quality of life and places a burden on families. There is evidence that overt HE might be prevented pharmacologically, but prophylaxis would be justified and cost effective only for patients at risk. We aimed to identify patients with cirrhosis at risk for overt HE.

METHODS

We collected data from October 2009 through December 2012 for 216 consecutive patients with cirrhosis (based on liver biopsy, 96 patients with minimal HE), admitted to the Gastroenterology Unit at the University of Rome. Patients were followed up and evaluated for an average of 14.7 ± 11.6 months; development of overt HE was recorded. We analyzed end-stage liver disease scores, shunt placement, previous overt or minimal HE, psychometric hepatic encephalopathy score (PHES), and levels of albumin, bilirubin, creatinine, and sodium to develop a prediction model. We validated the model in 112 patients with cirrhosis seen at the University of Padua and followed up for 12 ± 9.5 months.

RESULTS

During the follow-up period, 68 patients (32%) developed at least 1 episode of overt HE. Based on multivariate analysis, the development of overt HE was associated with previous HE, minimal HE (based on PHES), and level of albumin less than 3.5 g/dL (area under curve [AUC], 0.74). A model that excluded minimal HE but included albumin level and previous HE also identified patients who would develop overt HE (AUC, 0.71); this difference in AUC values was not statistically significant (P = .104). Both models were validated in the independent group of patients (3 variables: AUC, 0.74; 95% confidence interval, 0.66-0.83; and 2 variables: AUC, 0.71; 95% confidence interval, 0.63-0.78).

CONCLUSIONS

We developed and validated a model to identify patients with cirrhosis at risk for overt HE based on previous HE, albumin levels, and PHES. If PHES was not available, previous HE and albumin levels still can identify patients at risk. Psychometric evaluation is essential for patients with no history of HE. These findings should aid in planning studies of pharmacologic prevention of overt HE.

Endothelial dysfunction in cirrhosis: Role of inflammation and oxidative stress

This review describes the recent developments in the pathobiology of endothelial dysfunction (ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. ED characterised by an impaired bioactivity of nitric oxide (NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase (eNOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of eNOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.

Pathogenesis of hepatic encephalopathy: role of ammonia and systemic inflammation

The syndrome we refer to as Hepatic Encephalopathy (HE) was first characterized by a team of Nobel Prize winning physiologists led by Pavlov and Nencki at the Imperial Institute of Experimental Medicine in Russia in the 1890's. This focused upon the key observation that performing a portocaval shunt, which bypassed nitrogen-rich blood away from the liver, induced elevated blood and brain ammonia concentrations in association with profound neurobehavioral changes. There exists however a spectrum of metabolic encephalopathies attributable to a variety (or even absence) of liver hepatocellular dysfunctions and it is this spectrum rather than a single disease entity that has come to be defined as HE. Differences in the underlying pathophysiology, treatment responses and outcomes can therefore be highly variable between acute and chronic HE. The term also fails to articulate quite how systemic the syndrome of HE can be and how it can be influenced by the gastrointestinal, renal, nervous, or immune systems without any change in background liver function. The pathogenesis of HE therefore encapsulates a complex network of interdependent organ systems which as yet remain poorly characterized. There is nonetheless a growing recognition that there is a complex but influential synergistic relationship between ammonia, inflammation (sterile and non-sterile) and oxidative stress in the pathogenesis HE which develops in an environment of functional immunoparesis in patients with liver dysfunction. Therapeutic strategies are thus moving further away from the traditional specialty of hepatology and more towards novel immune and inflammatory targets which will be discussed in this review.

Cerebral haemodynamics in cirrhotic patients with hepatic encephalopathy

BACKGROUND & AIMS

Factors other than elevated levels of ammonia may be implicated in hepatic encephalopathy (HE) pathophysiology, including abnormal cerebral haemodynamics. Transcranial Doppler ultrasonography (TCD) evaluates cerebrovascular structural integrity and reactivity, through pulsatility index (PI) and breath-holding index (BHI) respectively. The aim of this study was to evaluate cerebral haemodynamics by TCD in patients with compensated and decompensated cirrhosis, and patients with and without HE.

METHODS

We studied 90 subjects by TCD measuring PI and BHI in the middle cerebral artery: 30 with cirrhosis and no HE, 30 with cirrhosis and low-grade HE and 30 healthy subjects. Critical flicker frequency, psychometric hepatic encephalopathy score and West-Haven criteria were performed to assess MHE and HE respectively.

RESULTS

Pulsatility index increased in decompensated cirrhotics (Child ≥ 7) when compared with compensated cirrhotics and healthy subjects [median (IQR) 1.07 (0.95-1.21) vs 0.90 (0.83-1.05) vs 0.87 (0.78-0.96); P < 0.001]. A reverse relationship was observed for BHI among the three groups [0.82 (0.45-1.11) vs 1.20 (0.82-1.52) vs 1.28 (1.06-1.68); P < 0.001]. Similar findings were observed in decompensation [model for end-stage liver disease (MELD) score ≥14]. Patients with HE showed higher PI and lower BHI [1.05 (1.00-1.16) and 0.89 (0.59-1.15)], when compared with patients without HE [0.96 (0.83-1.13) and 1.00 (0.60-1.53)] or controls [0.87 (0.78-0.96) and 1.28 (1.06-1.68)] (P < 0.001 for PI, and P = 0.007 for BHI). In multivariate regression models, only PI predicted HE, but it was outperformed by MELD-sodium and tumour necrosis factor-alpha.

CONCLUSIONS

These results indicate that cerebral haemodynamics are altered in patients with cirrhosis, in relation to severity of disease and HE. Findings on impaired PI and BHI suggest that structural vascular damage and loss of vascular autoregulation are implicated in the pathophysiology of HE.

Hepatic encephalopathy in patients with acute decompensation of cirrhosis and acute-on-chronic liver failure

Hepatic encephalopathy in a hospitalized cirrhotic patient is associated with a high mortality rate and its presence adds further to the mortality of patients with acute-on-chronic liver failure (ACLF). The exact pathophysiological mechanisms of HE in this group of patients are unclear but hyperammonemia, systemic inflammation (including sepsis, bacterial translocation, and insulin resistance) and oxidative stress, modulated by glutaminase gene alteration, remain as key factors. Moreover, alcohol misuse, hyponatremia, renal insufficiency, and microbiota are actively explored. HE diagnosis requires exclusion of other causes of neurological, metabolic and psychiatric dysfunction. Hospitalization in the ICU should be considered in every patient with overt HE, but particularly if this is associated with ACLF. Precipitating factors should be identified and treated as required. Evidence-based specific management options are limited to bowel cleansing and non-absorbable antibiotics. Ammonia lowering drugs, such as glycerol phenylbutyrate and ornithine phenylacetate show promise but are still in clinical trials. Albumin dialysis may be useful in refractory cases. Antibiotics, prebiotics, and treatment of diabetes reduce systemic inflammation. Where possible and not contraindicated, large portal-systemic shunts may be embolized but liver transplantation is the most definitive step in the management of HE in this setting. HE in patients with ACLF appears to be clinically and pathophysiologically distinct from that of acute decompensation and requires further studies and characterization.

Albumin infusion improves renal blood flow autoregulation in patients with acute decompensation of cirrhosis and acute kidney injury

BACKGROUND & AIMS

In cirrhotic patients with renal failure, renal blood flow autoregulation curve is shifted to the right, which is consequent upon sympathetic nervous system activation and endothelial dysfunction. Albumin infusion improves renal function in cirrhosis by mechanisms that are incompletely understood. We aimed to determine the effect of albumin infusion on systemic haemodynamics, renal blood flow, renal function and endothelial function in patients with acute decompensation of cirrhosis and acute kidney injury.

METHODS

Twelve patients with refractory ascites and 10 patients with acute decompensation of cirrhosis and acute kidney injury were studied. Both groups were treated with intravenous albumin infusion, 40-60 g/days over 3-4 days. Cardiac and renal haemodynamics were measured. Endothelial activation/dysfunction was assessed using von Willebrand factor and serum nitrite levels. F2α Isoprostanes, resting neutrophil burst and noradrenaline levels were quantified as markers of oxidative stress, endotoxemia and sympathetic activation respectively.

RESULTS

Albumin infusion leads to a shift in the renal blood flow autoregulation curve towards normalization, which resulted in a significant increase in renal blood flow. Accordingly, improvement of renal function was observed. In parallel, a significant decrease in sympathetic activation, inflammation/oxidative stress and endothelial activation/dysfunction was documented. Improvement of renal blood flow correlated with improvement in endothelial activation (r = 0.741, P < 0.001).

CONCLUSIONS

The data suggest that albumin infusion improves renal function in acutely decompensated cirrhotic patients with acute kidney injury by impacting on renal blood flow autoregulation. This is possibly achieved through endothelial stabilization and a reduction in the sympathetic tone, endotoxemia and oxidative stress.

Role of human albumin in the management of complications of liver cirrhosis

Albumin is a negatively charged, relatively small protein synthesized by liver cells. Is the most abundant protein in extracellular fluid and accounts for about 70% of the plasma colloid osmotic pressure. Therefore it plays a crucial role in regulating fluid distribution in the body. In addition, albumin possesses functional domains with important non-oncotic properties, such as potent anti-oxydant and scavenging activities, binding of highly toxic reactive metal species and a great amount of endogenous and exogenous substances. We have recently learned that albumin in cirrhosis undergoes a number of post-transcriptional changes that greatly impair its non-oncotic properties. The overall assessment of these changes clearly shows that the relative abundance of the native form of albumin is significantly reduced in hospitalized patients with cirrhosis and that these abnormalities worsen in parallel with the increasing severity of the disease. Thus, it is time to abandon the concept of serum albumin concentration and refer to the effective albumin concentration, that is the native intact albumin. Given the pathophysiological context in which we use human albumin in patients with cirrhosis, who are characterized by peripheral vasodilation and a low-grade but sustained inflammatory state, the use of albumin in patients with cirrhosis should aim at enhancing effective hypovolemia and exploiting its antioxidant and scavenging activities. The indications for the use of albumin in cirrhosis that clearly emerge from evidence-based medicine are represented by conditions characterized by an acute aggravation of effective hypovolemia and inflammation, such as such post-paracentesis circulatory dysfunction, spontaneous bacterial peritonitis, and hepatorenal syndrome. Other indications to the use of albumin that still require further studies are represented by bacterial infections other than spontaneous bacterial peritonitis, hepatic encephalopathy and long-term treatment of ascites, which has been debated for the last half-century.

Randomized pilot study: effects of an exercise programme and leucine supplementation in patients with cirrhosis

BACKGROUND

Physical exercise could improve functional limitations, muscle mass, and health-related quality of life (HRQoL) in patients with cirrhosis.

AIM

The purpose of this study was to evaluate the efficacy and safety of an exercise programme and leucine supplementation to increase exercise capacity, muscle mass, and HRQoL in patients with cirrhosis.

PATIENTS AND METHODS

Seventeen outpatients with cirrhosis were randomized to an exercise group (n = 8) or a control group (n = 9) in a pilot study. The programme of moderate exercise was performed for 12 weeks under supervision of a physiotherapist. All patients received oral leucine (10 g/day) during the study. At baseline and at the end of the study, we determined exercise capacity (6-min walk and 2-min step tests), anthropometric measurements, and HRQoL by Short Form-36 (SF-36) questionnaire. We also analyzed safety regarding complications of cirrhosis, liver and renal function, inflammatory response and oxidative stress.

RESULTS

In the exercise group, exercise capacity improved, as shown by the increase in the 6-min walk test from 365 (160-420) to 445 m (250-500) (p = 0.01), and in the 2-min step test (p = 0.02). Lower thigh circumference also increased, from 41 (34-53) to 46 cm (36-56) (p = 0.02), and the domains of SF-36 general health (p = 0.03), vitality (p = 0.01) and social function (p = 0.04) improved significantly. In the control group, no statistically significant changes were observed in any of the parameters. We did not observe complications of cirrhosis in either group during the study.

CONCLUSIONS

A programme of moderate physical exercise together with leucine supplements in patients with cirrhosis is safe and improves exercise capacity, leg muscle mass and HRQoL.

Hepatic Encephalopathy: From the Pathogenesis to the New Treatments

Hepatic encephalopathy is a frequent and serious complication of liver cirrhosis; the pathophysiology of this complication is not fully understood although great efforts have been made during the last years. There are few prospective studies on the epidemiology of this complication; however, it is known that it confers with high short-term mortality. Hepatic encephalopathy has been classified into different groups depending on the degree of hepatic dysfunction, the presence of portal-systemic shunts, and the number of episodes. Due to the large clinical spectra of overt EH and the complexity of cirrhotic patients, it is very difficult to perform quality clinical trials for assessing the efficacy of the treatments proposed. The physiopathology, clinical manifestation, and the treatment of HE is a challenge because of the multiple factors that converge and coexist in an episode of overt HE.

Ammonia clearance with haemofiltration in adults with liver disease

BACKGROUND & AIMS

Ammonia is recognized as a toxin central to complications of liver failure. Hyperammonaemia has important clinical consequences, but optimal means to reduce circulating levels are uncertain. In patients with liver disease, continuous renal replacement therapy (CRRT) with haemofiltration (HF) is often required to treat concurrent kidney injury, but its effects upon ammonia levels are poorly characterized. To evaluate the effect of HF at different treatment intensities on ammonia clearance (AC) and arterial ammonia concentration.

METHODS

Prospective study of adult patients with liver failure and arterial ammonia >100 μmol/L requiring CRRT using veno-venous HF. Arterial ammonia concentration and AC measured at 1 and 24 h after initiation of low (35 ml/kg/h) or high (90 ml/kg/h) filtration volume.

RESULTS

Twenty-four patients (10 acute liver failure, 10 chronic liver disease and 4 following liver resection) were studied. Clearance of urea and ammonia solutes correlated closely (r = 0.819, P = 0.007). Ammonia clearance correlated closely with ultrafiltration rate (r = 0.86, P < 0.001). At 1 h, AC was 39 (34-54) ml/min (low volume) vs 85 (62-105) ml/min (high volume) CRRT, (P < 0.001) and at 24 h 44 (34-63) vs 105 (82-109) ml/min, (P = 0.01). Overall, a 22% reduction in median arterial ammonia concentration was observed over 24 h of HF from 156 (137-176) to 122 (85-133) μmol/L, (P ≤ 0.0001).

CONCLUSION

Clinically significant ammonia clearance can be achieved in adult patients with hyperammonaemia utilizing continuous VVHF. Ammonia clearance is closely correlated with ultrafiltration rate. HF was associated with a fall in arterial ammonia concentration.

Recent insights into the pathogenesis of hepatic encephalopathy and treatments

Hepatic encephalopathy (HE) encompasses a spectrum of neuropsychiatric disorders related to liver failure. The development of HE can have a profound impact on mortality as well as quality of life for patients and carers. Ammonia is central in the disease process contributing to alteration in neurotransmission, oxidative stress, and cerebral edema and astrocyte swelling in acute liver failure. Inflammation in the presence of ammonia coactively worsens HE. Inflammation can result from hyperammonemic responses, endotoxemia, innate immune dysfunction or concurrent infection. This review summarizes the current processes implicated in the pathogenesis of HE, as well as current and potential treatments. Treatments currently focus on reducing inflammation and/or blood ammonia levels and provide varying degrees of success. Optimization of current treatments and initial testing of novel therapies will provide the basis of improvement of care in the near future.

Effects of intravenous albumin in patients with cirrhosis and episodic hepatic encephalopathy: a randomized double-blind study

BACKGROUND & AIMS

Episodic hepatic encephalopathy is frequently precipitated by factors that induce circulatory dysfunction, cause oxidative stress-mediated damage or enhance astrocyte swelling. The administration of albumin could modify these factors and improve the outcome of hepatic encephalopathy. The aim of this study is to assess the efficacy of albumin in a multicenter, prospective, double-blind, controlled trial (ClinicalTrials.gov number, NCT00886925).

METHODS

Cirrhotic patients with an acute episode of hepatic encephalopathy (grade II-IV) were randomized to receive albumin (1.5g/kg on day 1 and 1.0g/kg on day 3) or isotonic saline, in addition to the usual treatment (laxatives, rifaximin 1200mg per day). The primary end point was the proportion of patients in which encephalopathy was resolved on day 4. The secondary end points included survival, length of hospital stay, and biochemical parameters.

RESULTS

Fifty-six patients were randomly assigned to albumin (n=26) or saline (n=30) stratified by the severity of HE. Both groups were comparable regarding to demographic data, liver function, and precipitating factors. The percentage of patients without hepatic encephalopathy at day 4 did not differ between both groups (albumin: 57.7% vs. saline: 53.3%; p>0.05). However, significant differences in survival were found at day 90 (albumin: 69.2% vs. saline: 40.0%; p=0.02).

CONCLUSIONS

Albumin does not improve the resolution of hepatic encephalopathy during hospitalization. However, differences in survival after hospitalization suggest that the development of encephalopathy may identify a subgroup of patients with advanced cirrhosis that may benefit from the administration of albumin.

Albumin: pathophysiologic basis of its role in the treatment of cirrhosis and its complications

Since the introduction of human serum albumin as a plasma expander in the 1940s, considerable research has allowed a better understanding of its biochemical properties and potential clinical benefits. Albumin has a complex structure, which is responsible for a variety of biological functions. In disease, the albumin molecule is susceptible to modifications that may alter its biological activity. During the last decades, different methods to measure albumin function have been developed. Recent studies have shown that not only albumin concentration but also albumin function is reduced in liver failure. This observation led to the concept of effective albumin concentration, which represents the fact that plasma albumin concentration does not reflect its function. Indeed, in liver disease albumin function is several times less than its concentration. In patients with cirrhosis, albumin infusion reduces mortality in patients with spontaneous bacterial peritonitis and improves outcome following large volume paracentesis. In combination with vasoconstrictors, albumin is useful in the management of patients with hepatorenal syndrome. Its role is being investigated in a large number of indications, which rely on its volume and nonvolume expansion functions such as stroke, severe sepsis, Alzheimer's disease, malaria, burns, and ovarian hyperstimulation syndrome. This review explores the above concepts, reviews the available evidence for the use of albumin in liver diseases, defines therapeutic limitations, and explores the challenges that should be addressed in future research.

Inflammation and hepatic encephalopathy

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome associated with both acute and chronic liver dysfunction, spanning a spectrum that ranges from mild neuropsychological disturbances to coma. The central role of ammonia in the pathogenesis of HE remains incontrovertible however, there is a robust evidence base indicating the important role of inflammation in exacerbating the neurological effects of HE. Inflammation can arise directly within the brain itself as a result of deranged nitrogen and energy homeostasis, with resultant neuronal, astrocyte and microglial dysfunction. Inflammation may also originate in the peripheral circulation and exert effects on the brain indirectly, via the release of pro-inflammatory mediators which directly signal to the brain via the vagus nerve. This review summarises the data that demonstrate the synergistic relationship of inflammation and ammonia that culminates in the manifestation of HE. Sterile inflammation arising from the inflamed or necrotic liver, circulating endotoxin arising from the gut (bacterial translocation) inducing immune dysfunction, and superimposed sepsis will be comprehensively discussed. Finally, this review will provide an overview of the existing and novel treatments on the horizon which can target the inflammatory response, and how they might translate into clinical practise as therapies in the prophylaxis and treatment of HE.

Systemic inflammation and ammonia in hepatic encephalopathy

Infection and inflammation have been associated with the development of delirium for many centuries and there is a rapidly growing evidence base supporting the role of inflammation in exacerbating the neurological manifestations of both acute and chronic liver failure. Inflammation in the context of hepatic encephalopathy (HE) can arise directly within the brain itself resulting in astrocytic, microglial and neuronal dysfunction, impacting on the development of 'brain failure'. Inflammation may also develop systemically and indirectly influence brain function. Systemic inflammation develops following liver injury, resulting in hyperammonemia and a 'cytotoxic soup' of pro-inflammatory mediators which are released into the circulation and modulate the impact of ammonia on the brain. The aim of this review is to summarise the current evidence base supporting the synergistic role of systemic inflammation and hyperammonemia in the pathogenesis of hepatic encephalopathy. Systemic inflammation and ammonia induce neutrophil degranulation and release reactive oxygen species into the peripheral circulation that may ultimately cross the blood brain barrier. Circulating endotoxin arising from the gut (bacterial translocation), superimposed sepsis, and hyperammonemia upregulate the expression of microbial pattern recognition receptors such as Toll-like receptors. The early recognition and management of systemic inflammation may not only facilitate improved outcomes in HE but supports the development of novel therapeutic strategies that reduce circulating endotoxemia and immune cell dysfunction.

Reduction in hyperammonaemia by ornithine phenylacetate prevents lipopolysaccharide-induced brain edema and coma in cirrhotic rats

OBJECTIVE

In liver failure, inflammation synergistically exacerbates the deleterious cerebral effects of ammonia. The aims were to test whether treatment with the ammonia-lowering agent ornithine phenylacetate (OP) and/or anti-TNF-α (infliximab) prevent the deleterious brain consequences of lipopolysaccharide (LPS) in cirrhotic rats.

DESIGN

Rats 4 weeks following bile duct-ligation (BDL), sham-operation (sham) and/or 7 days hyperammonemic feed (HD), were randomized to receive LPS (1 mg/kg) or saline, and treatment with either 3 days intraperitoneal injections of OP (0.6 g/kg) and/or infliximab, 10 mg/kg. Animals were sacrificed at coma stages or at 3 h.

RESULTS

In sham rats, both HD and LPS increased brain water, with an increase in ammonia in the former and brain cytokines in the latter but with no effect on consciousness. BDL + HD rats caused significantly higher plasma ammonia, TNF-α and IL-6 levels compared to sham. LPS significantly worsened coma stage, increased brain water and plasma and brain TNF-α. OP significantly delayed LPS-induced progression to coma stages (P < 0.009), reduced arterial ammonia and brain water (P < 0.001 and P < 0.01 respectively), which was associated with a significant reduction in cytokines. Infliximab significantly reduced plasma and brain cytokines, but not brain water. OP + infliximab attenuated increase in brain water and delayed occurrence of coma, which was not different to OP alone. In BDL rats, OP reduced the expression of brain iNOS and NFκB.

CONCLUSION

Reduction in ammonia with OP in cirrhotic rats prevents LPS-induced brain edema and delays coma, suggesting that ammonia may prime the brain to the deleterious effect of LPS, possibly through effects on iNOS and NFκB related mechanisms.

Albumin for end-stage liver disease

Albumin has been widely used in patients with cirrhosis in an attempt to improve circulatory and renal functions. The benefits of albumin infusions in preventing the deterioration in renal function associated with large-volume paracentesis, spontaneous bacterial peritonitis, and established hepatorenal syndrome in conjunction with a vasoconstrictor are well established. While some of these indications are supported by the results of randomized studies, others are based only on clinical experience and have not been proved in prospective studies. The paucity of well-designed trials, the high cost of albumin, the lack of a clear-cut survival benefit, and fear of transmitting unknown infections make the use of albumin controversial. The recent development of the molecular adsorbent recirculating system, an albumin dialysis, is an example of the capacity of albumin to act by mechanisms other than its oncotic effect. Efforts should be made to define the indications for albumin use, the dose required, and predictors of response, so that patients gain the maximum benefit from its administration.

Extent of reversibility of hepatic encephalopathy following liver transplantation

Although hepatic encephalopathy (HE) is prevalent in the cirrhotic population, it has also been considered a potentially reversible condition. Liver transplantation represents the ultimate reversal of the decompensated cirrhotic state and should provide the best option for the reversibility of HE. However, the neurologic compromise associated with HE in the cirrhotic patient may not be completely reversible. Theories regarding fixed structural and reversible metabolic deficits as well as persistence of the hyperdynamic state with continued portosystemic shunting have been proposed to explain this lack of complete reversibility. Whether this remnant neurologic deficit is clinically significant remains unclear.

The neurological manifestations of acute liver failure

Acute liver failure is a disorder which impacts on multiple organ systems and results from hepatocellular necrosis in a patient with no previous history of chronic liver disease. It typically culminates in the development of liver dysfunction, coagulopathy and encephalopathy, and is associated with high mortality in poor prognostic groups. In acute liver failure, some patients may develop cerebral edema and increased intracranial pressure although recent data suggest that intracranial hypertension is less frequent than previously described, complicating 29% of acute cases who have proceeded to grade 3/4 coma. Neurological manifestations are primarily underpinned by the development of brain edema. The onset of encephalopathy can be rapid and dramatic with the development of asterixis, delirium, hyperreflexia, clonus, seizures, extensor posturing and coma. Ammonia plays a definitive role in the development of cytotoxic brain edema. Patients with acute liver failure have a marked propensity to develop renal insufficiency and hence impaired ammonia excretion. The incidence of both bacterial and fungal infection occurs in approximately one third of patients. The relationship between inflammation, as opposed to infection, and progression of encephalopathy is similar to that observed in chronic liver disease. Intracranial pressure monitoring is valuable in identifying surges in intracranial hypertension requiring intervention. Insertion of an intracranial bolt should be considered only in the subgroup of patients who have progressed to grade 4 coma. Risk factors for developing intracranial hypertension are those with hyperacute and acute etiologies, progression to grade 3/4 hepatic encephalopathy, those who develop pupillary abnormalities (dilated pupils, sluggishly responsive to light) or seizures, have systemic inflammation, an arterial ammonia >150 μmol/L, hyponatremia, and those in receipt of vasopressor support. Strategies employed in patients with established encephalopathy (grade 3/4) aim to maintain freedom from infection/inflammatory milieu, provide adequate sedation, and correct hypo-osmolality.

Management of hepatic encephalopathy

Hepatic encephalopathy (HE), the neuropsychiatric presentation of liver disease, is associated with high morbidity and mortality. Reduction of plasma ammonia remains the central therapeutic strategy, but there is a need for newer novel therapies. We discuss current evidence supporting the use of interventions for both the general management of chronic HE and that necessary for more acute and advanced disease.

Interorgan ammonia metabolism in liver failure: the basis of current and future therapies

Hepatic encephalopathy complicates the course of both acute and chronic liver disease and its treatment remains an unmet clinical need. Ammonia is thought to be central in its pathogenesis and remains an important target of current and future therapeutic approaches. In liver failure, the main detoxification pathway of ammonia metabolism is compromised leading to hyperammonaemia. In this situation, the other ammonia-regulating pathways in multiple organs assume important significance. The present review focuses upon interorgan ammonia metabolism in health and disease describing the role of the key enzymes, glutamine synthase and glutaminase. Better understanding of these alternative pathways are leading to the development of new therapeutic approaches.

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.

Changing face of hepatic encephalopathy: Role of inflammation and oxidative stress

The face of hepatic encephalopathy (HE) is changing. This review explores how this neurocognitive disorder, which is associated with both acute and chronic liver injury, has grown to become a dynamic syndrome that spans a spectrum of neuropsychological impairment, from normal performance to coma. The central role of ammonia in the pathogenesis of HE remains incontrovertible. However, over the past 10 years, the HE community has begun to characterise the key roles of inflammation, infection, and oxidative/nitrosative stress in modulating the pathophysiological effects of ammonia on the astrocyte. This review explores the current thoughts and evidence base in this area and discusses the potential role of existing and novel therapies that might abrogate the oxidative and nitrosative stresses inflicted on the brain in patients with, or at risk of developing, HE.