Nutritional support in hepatic encephalopathy

Nutrition Assessment and Management in Patients with Cirrhosis and Cognitive Impairment: A Comprehensive Review of Literature

Hepatic encephalopathy (HE) represents a common complication of liver cirrhosis. Protein-calorie malnutrition is frequently encountered in the cirrhotic patient and its most obvious clinical manifestation is sarcopenia. This condition represents a risk factor for HE occurrence because skeletal muscle acts as an alternative site for ammonium detoxification. Preventive intervention through an adequate assessment of nutritional status should be carried out at early stages of the disease and in a multidisciplinary team using both non-instrumental methods (food diary, anthropometric measurements, blood chemistry tests) and instrumental methods (bioimpedance testing, DEXA, CT, indirect calorimetry, dynamometry). Dietary recommendations for patients with HE do not differ from those for cirrhotic patient without HE. Daily caloric intake in the non-obese patient should be 30–40 Kcal/Kg/day with a protein intake of 1–1.5 g/Kg/day, especially of vegetable origin, through 4–6 meals daily. In patients with HE, it is also essential to monitor electrolyte balance, supplementing any micronutrient deficiencies such as sodium and zinc, as well as vitamin deficiencies because they can cause neurological symptoms similar to those of HE. In light of the critical role of nutritional status, this aspect should not be underestimated and should be included in the diagnostic–therapeutic algorithm of patients with HE.

A Look into Liver Mitochondrial Dysfunction as a Hallmark in Progression of Brain Energy Crisis and Development of Neurologic Symptoms in Hepatic Encephalopathy

BACKGROUND

The relationship between liver disease and neuropathology in hepatic encephalopathy is well known, but the genesis of encephalopathy in liver failure is yet to be elucidated. Conceptually, the main cause of hepatic encephalopathy is the accumulation of brain ammonia due to impaired liver detoxification function or occurrence of portosystemic shunt. Yet, as well as taking up toxic ammonia, the liver also produces vital metabolites that ensure normal cerebral function. Given this, for insight into how perturbations in the metabolic capacity of the liver may be related to brain pathology, it is crucial to understand the extent of ammonia-related changes in the hepatic metabolism that provides respiratory fuel for the brain, a deficiency of which can give rise to encephalopathy.

METHODS

Hepatic encephalopathy was induced in starved rats by injection of ammonium acetate. Ammonia-induced toxicity was evaluated by plasma and freeze-clamped liver and brain energy metabolites, and mitochondrial, cytoplasmic, and microsomal gluconeogenic enzymes, including mitochondrial ketogenic enzymes. Parameters of oxidative phosphorylation were recorded polarographically with a Clark-type electrode, while other measures were determined with standard fluorometric enzymatic methods.

RESULTS

Progressive impairment of liver mitochondrial respiration in the initial stage of ammonia-induced hepatotoxicity and the subsequent energy crisis due to decreased ATP synthesis lead to cessation of gluconeogenesis and ketogenesis. Reduction in glucose and ketone body supply to the brain is a terminal event in liver toxicity, preceding the development of coma.

CONCLUSIONS

Our study provides a framework to further explore the relationship between hepatic dysfunction and progression of brain energy crisis in hepatic encephalopathy.

Safety of an Immune-Enhancing Nutrition Supplement in Cirrhotic Patients With History of Encephalopathy

Malnutrition in advanced cirrhosis may worsen liver function and increase susceptibility to infections. Immune-enhancing nutrition supplements (IENS) may be of value, but their safety in patients with decompensated cirrhosis and history of encephalopathy is unknown. We assessed the safety of Impact Recover (Novartis, St. Louis Park, MN), an orally palatable IENS, in 12 men with hepatic cirrhosis of Child-Turcotte-Pugh (CTP) class B or C, ages 40-60. On day 0, patients were evaluated serially for 6 hours after ingestion of 2 packets of Impact Recover. Despite a transient doubling of the blood ammonia, no cognitive abnormalities were noted on clinical assessment or psychometric testing. Subsequently, patients were instructed to ingest 3 packets per day of Impact Recover for 56 days, after which supplements were stopped. Patients were evaluated in a fasting state on days 0 (baseline), 56 (end of treatment), and 112 (follow-up). One patient was transplanted on day 21, and another died after an urgent cholecystectomy on day 30. The remaining 10 patients completed the study. Mean value of CTP score was 9 (range, 7-11) and mean value of model for end-stage liver disease (MELD) score was 14 (7-21), and there was no change after 8 weeks of IENS. Only 1 experienced transient worsening of encephalopathy after omitting lactulose. Performances on psychometric tests did not change. Transferrin levels increased rapidly with IENS, then returned toward baseline after IENS was stopped. Fasting insulin and peptide YY (PYY) levels also increased, but fasting glucose and hemoglobin A1C did not change. Trends in other nutrition and immune parameters did not reach significance. We conclude that acute and chronic administration of Impact Recover was well tolerated in cirrhotic patients with controlled encephalopathy. Further studies are justified to assess potential efficacy of long-term IENS in preventing infection and slowing progression in advanced cirrhosis.

Association between chronic hepatitis C virus infection and low muscle mass in US adults

Given that low muscle mass can lead to worse health outcomes in patients with chronic infections, we assessed whether chronic hepatitis C virus (HCV) infection was associated with low muscle mass among US adults. We performed a cross-sectional study of the National Health Examination and Nutrition Study (1999-2010). Chronic HCV-infected patients had detectable HCV RNA. Low muscle mass was defined as <10th percentile for mid-upper arm circumference (MUAC). Multivariable logistic regression was used to determine adjusted odds ratios (aORs) with 95% confidence intervals (CIs) of low muscle mass associated with chronic HCV. Among 18 513 adults, chronic HCV-infected patients (n = 303) had a higher prevalence of low muscle mass than uninfected persons (13.8% vs 6.7%; aOR, 2.22; 95% CI, 1.39-3.56), and this association remained when analyses were repeated among persons without significant liver fibrosis (aOR, 2.12; 95% CI, 1.30-3.47). This study demonstrates that chronic HCV infection is associated with low muscle mass, as assessed by MUAC measurements, even in the absence of advanced liver disease.

Hepatorenal syndrome: beyond liver failure

Critical care nurses occasionally confront patient conditions that are not common. One such condition is hepatorenal syndrome (HRS). Three primary processes contribute to regional alterations in circulation in the renal and splanchnic beds. These processes include effective hypovolemia from the massive release of vasoactive mediators, thereby underfilling circulation, systemic and splanchnic vasodilation along with renal vasoconstriction, and hyperdynamic circulation. A "second-hit" hypothesis, whereby a triggering event causes intravascular volume depletion, likely initiates the development of HRS. The idea of a second hit focuses the attention of the health care team on surveillance strategies to prevent or limit HRS in patients with advanced cirrhosis and ascites. The treatment goal is to restore systemic and splanchnic vasoconstriction, while promoting renal vasodilation, balance sodium, and achieve euvolemia. The critical care nurse must maintain ongoing education to care for the patient with this complex syndrome in order to prevent complications and death.

Hepatic encephalopathy as a complication of liver cirrhosis: an Asian perspective

Hepatic encephalopathy is one of the most important clinical manifestations in decompensated liver cirrhosis. Accepted concepts regarding the pathophysiology of hepatic encephalopathy are that the endogenous neurotoxic substances, including ammonia: (i) escape from catabolism by the liver due both to the impaired function of the cirrhotic liver and also to the presence of portal systemic shunting; (ii) circulate at elevated concentrations in the systemic blood flow; (iii) reach the brain through the blood-brain barrier; and (iv) impair cerebral function leading to disturbances of consciousness. The majority of these toxic substances are produced in the intestine by the bacterial flora, and are absorbed into the portal venous flow. The epidemiology of liver cirrhosis depends particularly on its etiology, and shows a marked geographic difference worldwide between Western, and Asian countries. Hepatic encephalopathy developed at an annual rate of 8% in cirrhotics in Far Eastern studies. In Eastern and Far East countries, therapeutic options are similar to those in the western hemisphere, but pronounced application of dietary restriction, antimicrobial agents, disaccharides, shunt obliteration and branched chain amino acids is noted. In spite of improved therapeutic options for encephalopathy, the long-term survival is still low. Thus, hepatic encephalopathy remains a serious complication of liver cirrhosis. Establishment of truly effective prevention modalities and broader application of liver transplantation will help rescue patients suffering from this complication of liver cirrhosis in the near future.

Dietary and nutritional indications in hepatic encephalopathy

The restriction of dietary protein has long been considered a main stay in the therapy of hepatic encephalopathy. More recently it has been recognized that protein energy malnutrition is frequent in advanced liver disease and may adversely affect the patients'outcome. Moreover studies on inter-organ ammonia exchange in liver cirrhosis have shown that the muscle may have a crucial role in ammonia detoxification. In light of these evidences nutritional guidelines have proposed that protein restriction should be avoided in patients with hepatic encephalopathy as protein requirement is even increased in cirrhotic patients. Survey about the current clinical practice show that protein restriction is still considered advisable in patients with hepatic encephalopathy, however a recent trial evidenced that a low protein diet in patients hospitalized for acute hepatic encephalopathy exacerbates protein breakdown without inducing any specific clinical benefit when compared to a normal protein regimen. The relevance of an adequate protein intake and possible strategies to implement protein tolerance are also discussed.

Metabolic profiling analysis of a D-galactosamine/lipopolysaccharide-induced mouse model of fulminant hepatic failure

The purpose of this study was to characterize the changes in metabolic intermediates and to investigate the metabolic profile of a mouse model of fulminant hepatic failure (FHF), induced by D-galactosamine/lipopolysaccharide (GalN/LPS). Plasma metabolite levels were detected using gas chromatography/time-of-flight mass spectrometry, and the acquired data were transferred into Simca-P and processed using principal components analysis (PCA). In total, 45 metabolites were identified from the 267 distinct compounds found in the study. Whereas significant differences were noted in the plasma levels of the control and FHF groups, no differences in gluconeogenesis or glycolysis were noted following GalN/LPS treatment. Our data also suggest that the production of ketone bodies, and the tricarboxylic acid and urea cycles, was inhibited. PCA data suggest that 5-hydroxyindoleacetic acid, glucose, beta-hydroxybutyrate, and phosphate parameters had the highest weights on each of the principal components, and that they were the most important metabolites contributing to the separation of groups. In conclusion, this metabonomic approach can be used as a powerful tool to characterize changes in metabolic intermediates and to search for metabolic markers under certain pathophysiological conditions, such as FHF. Our data also demonstrate that a combination of 5-hydroxyindoleacetic acid, glucose, beta-hydroxybutyrate, and phosphate concentrations in the plasma is a potential marker for FHF, as well as for the early prognosis of FHF.

Interaction of RNA-binding proteins HuR and AUF1 with the human ATF3 mRNA 3'-untranslated region regulates its amino acid limitation-induced stabilization

ATF3 expression is induced in cells exposed to a variety of stress conditions, including nutrient limitation. Here we demonstrated that the mechanism by which the ATF3 mRNA content is increased following amino acid limitation of human HepG2 hepatoma cells is mRNA stabilization. Analysis of ATF3 mRNA turnover revealed that the half-life was increased from about 1 h in control cells to greater than 8 h in the histidine-deprived state, demonstrating mRNA stabilization in response to nutrient deprivation. Treatment of HepG2 cells with thapsigargin, which causes endoplasmic reticulum stress, also increased the half-life of ATF3 mRNA. HuR is an RNA-binding protein that regulates both the stability and cytoplasmic/nuclear localization of mRNA species containing AU-rich elements. Another RNA-binding protein, AUF1, regulates target mRNA molecules by enhancing their decay. Amino acid limitation caused a slightly elevated mRNA level for HuR and AUF1 mRNA. The nuclear HuR protein content was unchanged, and AUF1 protein increased slightly after amino acid limitation, whereas the cytoplasmic levels of both HuR and AUF1 protein increased. Immunoprecipitation of HuR-RNA complexes followed by reverse transcriptase-PCR analysis showed that HuR interacted with ATF3 mRNA in vivo and that this interaction increased following amino acid limitation. In contrast, the interaction of AUF1 with the ATF3 mRNA is decreased in histidine-deprived cells relative to control cells. Suppression of HuR expression by RNA interference partially blocked the accumulation of ATF3 mRNA following amino acid deprivation. The results demonstrated that coordinated regulation of mRNA stability by HuR and AUF1 proteins contributes to the observed increase in ATF3 expression following amino acid limitation.

Evolution of intrahepatic carbon, nitrogen, and energy metabolism in a D-galactosamine-induced rat liver failure model

A clearer picture of the hepatic metabolic pathways affected by fulminant hepatic failure (FHF) would help develop nutritional support and nonsurgical therapies for FHF. We characterized the evolution of hepatic metabolism in a rat model of FHF using an isolated perfused liver system together with a mass-balance model of intermediary metabolism. Principal component analysis (PCA) was used to identify potential new sensitive markers for FHF. To induce FHF, rats were given two D-galactosamine injections under fasting conditions. Controls were fasted only. Livers were harvested 1, 4, 8, and 12 h later and perfused with Eagle minimal essential medium supplemented with amino acids and bovine serum albumin, and equilibrated with 95% O2/5% CO2. At the 1 h time point, lactate release increased concomitant with a decrease in gluconeogenesis, TCA cycle and mitochondrial electron transport fluxes. At 4 h, amino acid metabolism and urea cycle fluxes were significantly depressed. By 8 h, gluconeogenesis had switched to glycolysis. By 12 h, amino acid metabolism was broadly inhibited, and there was a net release of many amino acids. Mass-balance analysis shows that the main source of ATP production in the FHF liver gradually changed from mitochondrial oxidative phosphorylation to glycolysis. PCA suggests that a linear combination of glucose, lactate, and glutamine concentrations in arterial plasma is a sensitive marker for FHF. We conclude that D-galactosamine causes early mitochondrial dysfunction while glycolytic ATP synthesis remains functional. Markers that are indirectly linked to these pathways may be used to evaluate the progression of FHF.

CCAAT/enhancer-binding protein-beta is a mediator of the nutrient-sensing response pathway that activates the human asparagine synthetase gene

Transcription from the human asparagine synthetase (AS) gene is increased in response to either amino acid (amino acid response) or glucose (unfolded protein response) deprivation. These two independent pathways converge on the same set of genomic cis-elements within the AS promoter, which are referred to as nutrient-sensing response element (NSRE)-1 and -2, both of which are absolutely necessary for gene activation. The NSRE-1 sequence was used to identify the corresponding transcription factor by yeast one-hybrid screening. Based on those results, electrophoretic mobility shift assays for individual CCAAT/enhancer-binding protein-beta (C/EBP) family members were performed to test for supershifting of complexes by specific antibodies. The results indicated that of all the family members, C/EBPbeta bound to the NSRE-1 sequence to the greatest extent and that the absolute amount of this complex was increased when extracts from amino acid- or glucose-deprived cells were tested. Using electrophoretic mobility shift assays, mutation of the NSRE-1 sequence completely prevented formation of the C/EBPbeta-containing complexes. In contrast, mutation of the NSRE-2 sequence did not block C/EBPbeta binding. Overexpression in HepG2 hepatoma cells of the activating isoform of C/EBPbeta increased AS promoter-driven transcription, whereas the inhibitory dominant-negative isoform of C/EBPbeta blocked enhanced transcription following amino acid or glucose deprivation. Collectively, the results provide both in vitro and in vivo evidence for a role of C/EBPbeta in the transcriptional activation of the AS gene in response to nutrient deprivation.

Nutritional assessment in various stages of liver cirrhosis

OBJECTIVES

The aims of this study were to determine the prevalence of protein-calorie malnutrition, characteristics, and clinical importance of nutrition disorders in patients with liver cirrhosis according to severity of disease.

METHODS

Nutrition assessments such as subjective global assessment, anthropometric and biochemical measurements, immunocompentency, thiamin and riboflavin status in 60 patients with cirrhosis (33 male and 27 female) were recorded between June 1999 and December 1999 at an outpatient clinic at Ramathibodi Hospital, Bangkok, Thailand. The origin of liver disease was alcohol related in 50% of patients. Child-Pugh criteria were used to establish the severity of liver disease.

RESULTS

In terms of energy malnutrition, 13.3% of patients had ideal body weights below 90% and 11.7% had body mass indexes below 18.5 kg/m(2). Protein malnutrition (low albumin) and immunoincompetence (abnormal response to skin tests) were found much more frequently (45% and 22%) than energy malnutrition. Patients with alcoholic cirrhosis had ascites (P < 0.05) and hepatic encephalopathy (P < 0.001) more frequently and less triceps skinfold thickness than those with non-alcoholic cirrhosis. Subjective global assessment and serum proteins correlated with the degree of liver-function impairment, but immunologic tests correlated inversely in cirrhosis patients. Mean values for creatinine-height index, hemoglobin, cholesterol, and complement C4 showed significant decreases in severe liver failure (Child-Pugh class C) only in patients with alcoholic cirrhosis (P < 0.05). Malnutrition was correlated with the clinical severity of liver disease.

CONCLUSIONS

The study showed that protein-energy malnutrition is a common complication of liver cirrhosis. Nutritional disorders appeared to be related to the degree of liver injury and the etiology of nutritional disorders. Nutritional disorders were more severe with alcoholic cirrhosis than with non-alcoholic cirrhosis.

Vegetarian diets in hepatic encephalopathy: facts or fantasies?

Diet treatment characterized by a reduction in or a selection of food proteins is currently suggested in hepatic encephalopathy. This article is a review of the present knowledge about the characteristics and the rationale of vegetarian diets in cirrhotic patients with overt or latent encephalopathy. In addition, evidence relating diet and encephalopathy and the nutritional features and needs of cirrhotic patients is reported. Finally, the rationale of a diet based on vegetable and milk-derived proteins that may overcome the limits and the possible adverse effects of a strict vegetarian diet is presented.

Liver cirrhosis: rationale and modalities for nutritional support--the European Society of Parenteral and Enteral Nutrition consensus and beyond

Evaluation of nutritional status is a major problem in patients with liver cirrhosis this is due to water retention and the effect of liver function on protein synthesis. Despite problems evaluating the patient, malnutrition has been found to be a common complication in liver cirrhosis and is associated with poorer outcome. Nutritional restrictions, like protein restriction, are no longer recommended in most patients with liver cirrhosis but are considered harmful. An intake of 1 to 1.5 g/kg protein and 25 to 40 kcal/kg body weight a day is recommended (depending on the situation of the patient). If adequate intake cannot be achieved by oral nutrition, stepwise nutritional support with the introduction of an additional late evening meal, sip feeding or tube feeding is recommended. Parenteral nutrition should be used as a second line treatment for acutely ill patients. Data indicate that improvement of nutritional status prior to liver transplantation might reduce complications.